United States EPA-AA-RSPD-IM-96-2 

Environmental Protection Agency July 1996 

Air 

Acceleration Simulation Mode Test 

Procedures, Emission Standards, Quality 

Control Requirements, and Equipment 

Specifications 

Technical Guidance
 
Table of Contents 

Page 

§85.1 Test Standards and Calculations 1
 

(a) Emissions Standards 1
 

(b) Test Score Calculation 7
 

§85.2 Test Procedures 9
 

(a) General Requirements. 9
 

(b) Vehicle Pre-inspection and Preparation. 9
 

(c) Equipment Preparation and Settings. 10
 

(d) Test Procedure. 12
 

(e) Second Chance Tests. 15
 

§85.3 Test Equipment Specifications 16
 

(a) Dynamometer Specifications. 16
 

(b) Emission Sampling System. 19
 

(c) Analytical Instruments. 21
 

(d) Automated Test Process Software and Displays. 24
 

§85.4 Quality Control Requirements 26
 

(a) General Requirements 26
 

(b) Dynamometer 26
 

(c) Emission Sampling System. 30
 

(d) Analytic Instruments. 31
 

§85.5 Test Record Information 38
 

(a) General Information. 38
 

(b) Ambient Test Conditions. 38
 

(c) ASM Mode or Modes. 38
 

(d) Diagnostic/Quality Assurance Information. 38
 
§85.1	 §85.1 

§85.1 Test Standards and Calculations 

(a)	 Emissions Standards 

(1)	 Start-up ASM Standards. Start-up standards should be used during the first cycle of 

the program. The exhaust emissions standards for the following model years and 

vehicle types are cross-referenced by the number in the column in §85.1(a)(3), as 

noted in the column headings: 

(i)	 Light Duty Vehicles. 

Model Years Hydrocarbons Carbon Monoxide Oxides of Nitrogen 

Table §85.1 (a)(3)(i) Table §85.1 (a)(3)(ii) Table §85.1 (a)(3)(iii) 

1994+ Tier 1 1 21 41 

1991-1995 2 22 42 

1983-1990 4 23 43 

1981-1982 4 26 43 

1980 4 26 48 

1977-1979 11 30 48 

1975-1976 11 30 50 

1973-1974 13 34 50 

1968-1972 13 34 51 

(ii)	 High-Altitude Light Duty Vehicles. 

Model Years Hydrocarbons Carbon Monoxide Oxides of Nitrogen 

Table §85.1 (a)(3)(i) Table §85.1 (a)(3)(ii) Table §85.1 (a)(3)(iii) 

1983-1984 4 26 43 

1982 4 29 43 

(iii)	 Light Duty Trucks 1 (less than 6000 pounds GVWR). 

Model Years Hydrocarbons Carbon Monoxide Oxides of Nitrogen 

Table §85.1 (a)(3)(i) Table §85.1 (a)(3)(ii) Table §85.1 (a)(3)(iii) 

1994+ Tier 1 <3750 LVW 1 21 41 

1994+ Tier 1 >3750 LVW 2 22 42 

1991-1995 5 26 43 

1988-1990 7 29 44 

1984-1987 7 29 49 

1979-1983 11 31 49 

1975-1978 12 32 50 

1973-1974 13 34 50 

1968-1972 13 34 51 

(iv)	 High-Altitude Light Duty Trucks 1 (less than 6000 pounds GVWR). 

Model Years Hydrocarbons Carbon Monoxide Oxides of Nitrogen 

Table §85.1 (a)(3)(i) Table §85.1 (a)(3)(ii) Table §85.1 (a)(3)(iii) 

Page 1	 7/2/96 Test Standards and Calculations 
§85.1	 §85.1 

1991+ 6 28 43
 

1988-1990 9 30 44
 

1984-1987 9 30 49
 

1982-1983 12 33 49
 

(v)	 Light Duty Trucks 2 (greater than 6000 pounds GVWR). 

Model Years Hydrocarbons Carbon Monoxide Oxides of Nitrogen 

Table §85.1 (a)(3)(i) Table §85.1 (a)(3)(ii) Table §85.1 (a)(3)(iii) 

1994+ Tier 1 <5750 LVW 2 22 42
 

1994+ Tier 1 >5750 LVW 5 26 45
 

1991-1995 5 26 46
 

1988-1990 7 29 47
 

1984-1987 7 29 49
 

1979-1983 11 31 49
 

1975-1978 12 32 50
 

1973-1974 13 34 50
 

1968-1972 13 34 51
 

(vi)	 High-Altitude Light Duty Trucks 2 (greater than 6000 pounds GVWR). 

Model Years Hydrocarbons Carbon Monoxide Oxides of Nitrogen 

Table §85.1 (a)(3)(i) Table §85.1 (a)(3)(ii) Table §85.1 (a)(3)(iii) 

1991+ 6 28 46
 

1988-1990 9 30 47
 

1984-1987 9 30 49
 

1982-1983 12 33 49
 

(2)	 Final ASM Standards. The following exhaust emissions standards are designed to 

achieve the emission reduction credits issued by EPA. They should only be used 

after at least one cycle of operation using the start-up standards in §85.1(a)(1). The 

exhaust emissions standards for the following model years and vehicle types are 

cross-referenced by the number in the column in §85.1(a)(3), as noted in the column 

headings: 

(i)	 Light Duty Vehicles. 

Model Years Hydrocarbons Carbon Monoxide Oxides of Nitrogen 

Table §85.1 (a)(3)(i) Table §85.1 (a)(3)(ii) Table §85.1 (a)(3)(iii) 

1994+ Tier 1 1 21 41
 

1983-1995 1 21 41
 

1981-1982 1 23 41
 

1980 1 23 45
 

1977-1979 6 27 45
 

1975-1976 6 27 48
 

1973-1974 10 32 48
 

1968-1972 10 32 49
 

Page 2	 7/2/96 Test Standards and Calculations 
§85.1 §85.1 

(ii) High-Altitude Light Duty Vehicles. 

Model Years Hydrocarbons Carbon Monoxide Oxides of Nitrogen 

Table §85.1 (a)(3)(i) Table §85.1 (a)(3)(ii) Table §85.1 (a)(3)(iii) 

1983-1984 2 23 41 

1982 2 23 41 

(iii) Light Duty Trucks 1 (less than 6000 pounds GVWR). 

Model Years Hydrocarbons Carbon Monoxide Oxides of Nitrogen 

Table §85.1 (a)(3)(i) Table §85.1 (a)(3)(ii) Table §85.1 (a)(3)(iii) 

1994+ Tier 1 1 21 41 

1988-1995 3 24 42 

1984-1987 3 24 46 

1979-1983 8 28 46 

1975-1978 9 29 48 

1973-1974 10 32 48 

1968-1972 10 32 49 

(iv) High-Altitude Light Duty Trucks 1 (less than 6000 pounds GVWR). 

Model Years Hydrocarbons Carbon Monoxide Oxides of Nitrogen 

Table §85.1 (a)(3)(i) Table §85.1 (a)(3)(ii) Table §85.1 (a)(3)(iii) 

1988+ 4 26 42 

1984-1987 4 26 46 

1982-1983 9 30 46 

(v) Light Duty Trucks 2 (greater than 6000 pounds GVWR). 

Model Years Hydrocarbons Carbon Monoxide Oxides of Nitrogen 

Table §85.1 (a)(3)(i) Table §85.1 (a)(3)(ii) Table §85.1 (a)(3)(iii) 

1994+ Tier 1 1 21 41 

1988-1995 3 24 44 

1984-1987 3 24 46 

1979-1983 8 28 46 

1975-1978 9 29 48 

1973-1974 10 32 48 

1968-1972 10 32 49 

(vi) High-Altitude Light Duty Trucks 2 (greater than 6000 pounds GVWR). 

Model Years Hydrocarbons Carbon Monoxide Oxides of Nitrogen 

Table §85.1 (a)(3)(i) Table §85.1 (a)(3)(ii) Table §85.1 (a)(3)(iii) 

1988+ 4 26 44 

1984-1987 4 26 46 

1982-1983 9 30 46 

Page 3 7/2/96 Test Standards and Calculations 
§85.1 §85.1 

(3) ASM 2525 and 5015 Concentration Tables 

Column # 

ETW 

1750 

1875 

2000 

2125 

2250 

2375 

2500 

2625 

2750 

2875 

3000 

3125 

3250 

3375 

3500 

3625 

3750 

3875 

4000 

4125 

4250 

4375 

4500 

4625 

4750 

4875 

5000 

5125 

5250 

5375 

5500 

5625 

5750 

5875 

6000 

6125 

6250 

6375 

6500 

6625 

6750 

6875 

7000 

7125 

7250 

7375 

7500 

1 1 

5015 2525 

142 136 

134 129 

127 123 

121 116 

115 111 

109 106 

105 101 

100 97 

96 93 

92 89 

89 86 

86 83 

83 80 

81 78 

78 76 

76 74 

74 72 

72 70 

71 68 

69 67 

67 65 

66 64 

65 63 

63 61 

62 60 

61 59 

60 58 

58 57 

57 56 

56 55 

55 54 

54 53 

53 52 

52 51 

51 50 

50 49 

50 48 

49 48 

48 47 

48 46 

47 46 

47 46 

47 46 

47 46 

47 46 

47 46 

47 46 

(i) ASM2525 and ASM5015 Hydrocarbon (ppm C6) Table 

2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10 

5015 2525 5015 2525 5015 2525 5015 2525 5015 2525 5015 2525 5015 2525 5015 2525 5015 2525 

224 216 257 249 291 282 324 315 374 364 390 381 407 397 457 447 706 694 

212 205 243 236 275 266 306 297 353 344 368 359 384 375 431 421 665 653 

201 194 230 223 260 252 289 281 333 325 348 339 363 354 407 398 627 616 

191 184 219 212 246 239 274 267 316 308 329 321 343 335 385 376 592 582 

182 175 208 201 234 227 260 253 299 292 312 305 325 318 365 357 560 551 

173 167 198 192 223 216 247 241 284 277 297 290 309 302 346 339 531 522 

166 160 189 183 212 206 236 230 271 264 283 276 294 288 329 322 505 496 

159 153 181 175 203 197 225 219 259 252 270 263 281 274 314 307 481 472 

152 147 173 168 194 189 216 210 247 241 258 252 269 262 300 294 459 451 

146 141 167 161 187 181 207 201 237 231 247 241 257 251 287 281 439 431 

141 136 160 155 180 174 199 194 228 222 237 232 247 241 276 270 420 413 

136 132 155 150 173 168 191 186 219 214 228 223 238 232 265 260 404 397 

132 127 149 145 167 162 185 180 211 206 220 215 229 224 256 250 388 382 

128 123 145 140 162 157 179 174 204 199 213 208 221 216 247 241 374 368 

124 120 140 136 157 152 173 169 198 193 206 201 214 209 239 234 362 355 

120 117 136 132 152 148 168 164 192 187 200 195 207 203 231 226 350 344 

117 114 133 129 148 144 163 159 186 182 194 189 201 197 224 220 339 333 

114 111 129 125 144 140 159 155 181 177 188 184 196 191 218 213 329 323 

112 108 126 122 140 137 155 151 176 172 183 179 191 186 212 208 320 314 

109 106 123 119 137 133 151 147 172 168 179 175 186 181 206 202 311 305 

107 103 120 117 134 130 147 143 167 164 174 170 181 177 201 197 303 297 

104 101 118 114 131 127 144 140 164 160 170 166 177 173 196 192 295 290 

102 99 115 112 128 124 141 137 160 156 166 162 172 169 192 188 287 282 

100 97 113 109 125 122 137 134 156 152 162 159 169 165 187 183 280 275 

98 95 110 107 122 119 134 131 153 149 159 155 165 161 183 179 273 269 

96 93 108 105 120 117 132 128 149 146 155 152 161 157 179 175 267 262 

94 92 106 103 117 114 129 126 146 143 152 148 157 154 175 171 260 256 

93 90 104 101 115 112 126 123 143 139 148 145 154 150 171 167 254 250 

91 88 102 99 112 110 123 120 140 136 145 142 150 147 167 163 248 244 

89 86 100 97 110 107 121 118 137 133 142 139 147 144 163 159 242 238 

87 85 98 95 108 105 118 115 134 130 139 136 144 141 159 156 236 232 

86 83 96 93 106 103 116 113 131 128 136 133 141 138 156 152 231 226 

84 82 94 91 104 101 113 111 128 125 133 130 138 135 152 149 225 221 

83 80 92 90 102 99 111 108 125 122 130 127 135 132 149 146 220 216 

81 79 90 88 100 97 109 106 123 120 127 124 132 129 146 143 215 211 

80 78 89 86 98 95 107 104 120 118 125 122 129 126 143 140 210 206 

79 76 87 85 96 94 105 102 118 115 123 120 127 124 140 137 206 202 

77 75 86 84 95 92 103 101 116 113 120 118 125 122 138 135 202 198 

76 74 85 83 93 91 102 99 114 112 119 116 123 120 136 133 199 195 

76 74 84 82 92 90 101 98 113 110 117 114 121 119 134 131 196 192 

75 73 83 81 91 89 100 97 112 109 116 113 120 117 132 129 194 190 

75 73 83 81 91 89 99 97 111 109 115 113 119 117 132 129 193 189 

74 72 83 80 91 88 99 96 111 108 115 112 119 116 131 128 192 188 

74 72 82 80 90 88 98 96 111 108 115 112 119 116 131 128 192 188 

74 72 82 80 90 88 98 96 111 108 115 112 119 116 131 128 192 188 

74 72 82 80 90 88 98 96 111 108 115 112 119 116 131 128 192 188 

74 72 82 80 90 88 98 96 111 108 115 112 119 116 131 128 192 188 

11 

5015 

774 

729 

688 

650 

615 

583 

554 

528 

503 

481 

461 

443 

426 

411 

397 

384 

372 

361 

351 

341 

332 

323 

315 

308 

300 

293 

286 

279 

272 

266 

259 

253 

247 

241 

236 

231 

226 

222 

218 

215 

213 

211 

211 

211 

211 

211 

211 

11 

2525 

761 

717 

676 

638 

604 

573 

544 

518 

495 

473 

453 

435 

419 

404 

390 

377 

365 

355 

345 

335 

326 

318 

310 

302 

295 

288 

281 

274 

267 

261 

255 

248 

243 

237 

232 

227 

222 

218 

214 

211 

209 

207 

207 

206 

206 

206 

206 

12 

5015 

843 

794 

749 

707 

669 

635 

603 

574 

548 

524 

502 

482 

464 

447 

432 

418 

405 

393 

382 

371 

361 

352 

343 

335 

327 

319 

311 

304 

296 

289 

282 

276 

269 

263 

257 

251 

246 

242 

238 

234 

232 

230 

229 

229 

229 

229 

229 

12 

2525 

828 

780 

736 

695 

658 

624 

593 

564 

539 

515 

493 

474 

456 

440 

424 

411 

398 

386 

375 

365 

355 

346 

337 

329 

321 

313 

305 

298 

291 

284 

277 

271 

264 

258 

252 

247 

242 

237 

233 

230 

227 

225 

225 

225 

225 

225 

225 

13 

5015 

1118 

1052 

992 

938 

887 

841 

800 

761 

726 

695 

666 

639 

615 

593 

573 

554 

537 

521 

506 

492 

479 

467 

455 

444 

433 

423 

412 

402 

393 

383 

374 

365 

357 

348 

341 

333 

326 

320 

315 

310 

307 

305 

304 

304 

304 

304 

304 

13 

2525 

1098 

1034 

975 

921 

872 

827 

786 

748 

714 

683 

654 

628 

604 

583 

563 

544 

527 

512 

497 

484 

471 

459 

447 

436 

425 

415 

405 

395 

386 

376 

367 

359 

350 

342 

334 

327 

320 

314 

309 

304 

301 

299 

298 

298 

298 

298 

298 

Page 4 7/2/96 Test Standards and Calculations 
§85.1 §85.1 

(ii) ASM2525 and ASM5015 Carbon Monoxide (%CO) Table 

Column # 21 21 22 22 23 23 24 24 25 25 26 26 27 27 28 28 29 29 30 30 31 31 32 32 33 33 34 34 

ETW 5015 2525 5015 2525 5015 2525 5015 2525 5015 2525 5015 2525 5015 2525 5015 2525 5015 2525 5015 2525 5015 2525 5015 2525 5015 2525 5015 2525 

1750 0.80 0.77 1.26 1.22 1.64 1.83 2.02 2.43 2.21 2.73 2.78 3.64 2.97 3.94 3.16 4.24 3.54 4.85 3.92 5.45 4.31 6.06 5.07 7.26 5.26 7.44 8.02 9.90 

1875 0.75 0.73 1.19 1.16 1.55 1.72 1.91 2.29 2.09 2.58 2.63 3.43 2.81 3.71 2.98 4.00 3.34 4.57 3.70 5.14 4.06 5.70 4.78 6.84 4.96 7.05 7.56 9.90 

2000 0.71 0.69 1.13 1.09 1.47 1.63 1.81 2.17 1.97 2.43 2.48 3.24 2.65 3.51 2.82 3.77 3.16 4.31 3.49 4.85 3.83 5.38 4.51 6.45 4.68 6.68 7.14 9.90 

2125 0.68 0.66 1.07 1.04 1.39 1.54 1.71 2.05 1.87 2.30 2.35 3.06 2.51 3.32 2.67 3.57 2.99 4.08 3.31 4.58 3.63 5.09 4.26 6.10 4.43 6.34 6.75 9.66 

2250 0.64 0.62 1.02 0.99 1.32 1.47 1.62 1.94 1.77 2.18 2.23 2.90 2.38 3.14 2.53 3.38 2.83 3.86 3.13 4.34 3.44 4.82 4.04 5.78 4.20 6.00 6.40 9.14 

2375 0.61 0.59 0.97 0.94 1.26 1.39 1.54 1.85 1.69 2.07 2.12 2.76 2.26 2.98 2.40 3.21 2.69 3.66 2.98 4.12 3.26 4.57 3.83 5.48 3.98 5.69 6.07 8.67 

2500 0.59 0.57 0.93 0.90 1.20 1.33 1.47 1.76 1.61 1.97 2.02 2.62 2.15 2.84 2.29 3.05 2.56 3.48 2.83 3.91 3.10 4.35 3.65 5.21 3.79 5.41 5.78 8.25 

2625 0.56 0.54 0.89 0.86 1.15 1.27 1.41 1.68 1.53 1.88 1.92 2.50 2.05 2.70 2.18 2.91 2.44 3.32 2.70 3.73 2.96 4.14 3.48 4.96 3.61 5.15 5.51 7.85 

2750 0.54 0.52 0.85 0.82 1.10 1.21 1.34 1.60 1.47 1.80 1.84 2.39 1.96 2.58 2.09 2.78 2.33 3.17 2.58 3.56 2.83 3.95 3.32 4.73 3.45 4.92 5.26 7.50 

2875 0.52 0.50 0.82 0.79 1.05 1.16 1.29 1.54 1.41 1.72 1.76 2.29 1.88 2.47 2.00 2.66 2.23 3.03 2.47 3.41 2.71 3.78 3.18 4.53 3.30 4.70 5.03 7.17 

3000 0.50 0.48 0.79 0.76 1.01 1.12 1.24 1.48 1.35 1.66 1.69 2.19 1.80 2.37 1.92 2.55 2.14 2.91 2.37 3.27 2.60 3.62 3.05 4.34 3.17 4.51 4.83 6.87 

3125 0.48 0.46 0.76 0.73 0.98 1.08 1.19 1.42 1.30 1.59 1.63 2.11 1.74 2.28 1.84 2.45 2.06 2.79 2.28 3.14 2.50 3.48 2.93 4.17 3.04 4.33 4.64 6.60 

3250 0.46 0.45 0.73 0.71 0.94 1.04 1.15 1.37 1.26 1.53 1.57 2.03 1.67 2.20 1.78 2.36 1.99 2.69 2.20 3.02 2.40 3.35 2.82 4.01 2.93 4.17 4.47 6.35 

3375 0.45 0.43 0.71 0.69 0.91 1.00 1.11 1.32 1.21 1.48 1.52 1.96 1.62 2.12 1.72 2.28 1.92 2.60 2.12 2.91 2.32 3.23 2.72 3.87 2.83 4.02 4.31 6.13 

3500 0.44 0.42 0.69 0.67 0.88 0.97 1.08 1.28 1.17 1.43 1.47 1.89 1.56 2.05 1.66 2.20 1.86 2.51 2.05 2.82 2.24 3.12 2.63 3.74 2.73 3.88 4.17 5.92 

3625 0.42 0.41 0.67 0.65 0.86 0.94 1.05 1.24 1.14 1.39 1.42 1.84 1.52 1.98 1.61 2.13 1.80 2.43 1.99 2.73 2.17 3.02 2.55 3.62 2.65 3.76 4.04 5.73 

3750 0.41 0.40 0.65 0.63 0.83 0.92 1.02 1.20 1.11 1.35 1.38 1.78 1.47 1.92 1.56 2.07 1.74 2.36 1.93 2.64 2.11 2.93 2.47 3.51 2.57 3.64 3.91 5.55 

3875 0.40 0.39 0.63 0.61 0.81 0.89 0.99 1.17 1.08 1.31 1.34 1.73 1.43 1.87 1.52 2.01 1.69 2.29 1.87 2.57 2.05 2.85 2.40 3.40 2.49 3.54 3.80 5.39 

4000 0.39 0.38 0.62 0.60 0.79 0.87 0.96 1.14 1.05 1.28 1.31 1.68 1.39 1.82 1.48 1.95 1.65 2.22 1.82 2.49 1.99 2.77 2.33 3.31 2.43 3.44 3.70 5.24 

4125 0.38 0.37 0.60 0.58 0.77 0.85 0.94 1.11 1.02 1.24 1.27 1.64 1.36 1.77 1.44 1.90 1.61 2.16 1.77 2.43 1.94 2.69 2.27 3.22 2.36 3.34 3.60 5.09 

4250 0.37 0.36 0.59 0.57 0.75 0.83 0.92 1.08 1.00 1.21 1.24 1.60 1.32 1.72 1.40 1.85 1.56 2.11 1.73 2.36 1.89 2.62 2.21 3.13 2.30 3.25 3.51 4.96 

4375 0.36 0.35 0.58 0.56 0.74 0.81 0.89 1.06 0.97 1.18 1.21 1.56 1.29 1.68 1.37 1.81 1.53 2.06 1.68 2.31 1.84 2.55 2.16 3.05 2.24 3.17 3.42 4.83 

4500 0.36 0.35 0.57 0.55 0.72 0.79 0.87 1.03 0.95 1.16 1.18 1.52 1.26 1.64 1.34 1.76 1.49 2.01 1.64 2.25 1.80 2.49 2.11 2.98 2.19 3.09 3.34 4.71 

4625 0.35 0.34 0.55 0.54 0.70 0.77 0.85 1.01 0.93 1.13 1.15 1.48 1.23 1.60 1.30 1.72 1.46 1.96 1.61 2.19 1.76 2.43 2.06 2.90 2.14 3.02 3.26 4.60 

4750 0.34 0.33 0.54 0.53 0.69 0.76 0.84 0.99 0.91 1.10 1.13 1.45 1.20 1.57 1.28 1.68 1.42 1.91 1.57 2.14 1.72 2.37 2.01 2.83 2.09 2.95 3.18 4.49 

4875 0.34 0.33 0.53 0.52 0.67 0.74 0.82 0.97 0.89 1.08 1.10 1.42 1.17 1.53 1.25 1.64 1.39 1.87 1.53 2.09 1.68 2.32 1.96 2.77 2.04 2.87 3.11 4.38 

5000 0.33 0.32 0.52 0.51 0.66 0.73 0.80 0.95 0.87 1.05 1.08 1.38 1.15 1.49 1.22 1.60 1.36 1.82 1.50 2.04 1.64 2.26 1.92 2.70 1.99 2.81 3.03 4.28 

5125 0.32 0.31 0.51 0.50 0.65 0.71 0.78 0.92 0.85 1.03 1.05 1.35 1.12 1.46 1.19 1.57 1.33 1.78 1.46 2.00 1.60 2.21 1.87 2.64 1.95 2.74 2.97 4.18 

5250 0.32 0.31 0.50 0.49 0.63 0.70 0.77 0.90 0.83 1.01 1.03 1.32 1.10 1.43 1.16 1.53 1.30 1.74 1.43 1.95 1.56 2.16 1.83 2.58 1.90 2.68 2.90 4.08 

5375 0.31 0.30 0.49 0.48 0.62 0.68 0.75 0.89 0.81 0.99 1.01 1.29 1.07 1.39 1.14 1.50 1.27 1.70 1.40 1.90 1.53 2.11 1.79 2.51 1.86 2.61 2.83 3.98 

5500 0.30 0.30 0.48 0.47 0.61 0.67 0.73 0.87 0.80 0.97 0.99 1.26 1.05 1.36 1.11 1.46 1.24 1.66 1.37 1.86 1.49 2.06 1.75 2.46 1.82 2.55 2.77 3.89 

5625 0.30 0.29 0.47 0.46 0.59 0.65 0.72 0.85 0.78 0.94 0.97 1.24 1.03 1.33 1.09 1.43 1.21 1.62 1.34 1.82 1.46 2.01 1.71 2.40 1.77 2.49 2.70 3.80 

5750 0.29 0.29 0.46 0.45 0.58 0.64 0.70 0.83 0.76 0.92 0.94 1.21 1.01 1.30 1.07 1.40 1.19 1.59 1.31 1.78 1.43 1.96 1.67 2.34 1.74 2.43 2.64 3.71 

5875 0.29 0.28 0.45 0.44 0.57 0.63 0.69 0.81 0.75 0.91 0.92 1.18 0.98 1.27 1.04 1.37 1.16 1.55 1.28 1.74 1.40 1.92 1.63 2.29 1.70 2.38 2.59 3.62 

6000 0.28 0.28 0.44 0.44 0.56 0.62 0.67 0.80 0.73 0.89 0.91 1.16 0.96 1.25 1.02 1.34 1.14 1.52 1.25 1.70 1.37 1.88 1.60 2.24 1.66 2.33 2.53 3.54 

6125 0.28 0.27 0.44 0.43 0.55 0.61 0.66 0.78 0.72 0.87 0.89 1.13 0.94 1.22 1.00 1.31 1.11 1.49 1.23 1.66 1.34 1.84 1.57 2.19 1.63 2.28 2.48 3.47 

6250 0.27 0.27 0.43 0.42 0.54 0.60 0.65 0.77 0.71 0.85 0.87 1.11 0.93 1.20 0.98 1.28 1.09 1.46 1.20 1.63 1.31 1.80 1.54 2.15 1.60 2.23 2.43 3.40 

6375 0.27 0.26 0.42 0.42 0.53 0.59 0.64 0.76 0.69 0.84 0.86 1.09 0.91 1.18 0.96 1.26 1.07 1.43 1.18 1.60 1.29 1.77 1.51 2.11 1.57 2.19 2.39 3.34 

6500 0.26 0.26 0.42 0.41 0.52 0.58 0.63 0.74 0.68 0.83 0.84 1.08 0.90 1.16 0.95 1.24 1.06 1.41 1.16 1.57 1.27 1.74 1.48 2.07 1.54 2.15 2.35 3.28 

6625 0.26 0.26 0.41 0.41 0.52 0.57 0.62 0.73 0.67 0.82 0.83 1.06 0.88 1.14 0.94 1.23 1.04 1.39 1.15 1.55 1.25 1.72 1.46 2.04 1.52 2.12 2.32 3.23 

6750 0.26 0.26 0.41 0.41 0.51 0.57 0.61 0.73 0.67 0.81 0.82 1.05 0.88 1.13 0.93 1.21 1.03 1.37 1.14 1.54 1.24 1.70 1.45 2.02 1.50 2.10 2.29 3.20 

6875 0.26 0.25 0.40 0.40 0.51 0.56 0.61 0.72 0.66 0.80 0.82 1.04 0.87 1.12 0.92 1.20 1.02 1.36 1.13 1.52 1.23 1.68 1.44 2.00 1.49 2.08 2.28 3.17 

7000 0.25 0.25 0.40 0.40 0.51 0.56 0.61 0.72 0.66 0.80 0.82 1.04 0.87 1.12 0.92 1.20 1.02 1.36 1.12 1.52 1.23 1.68 1.43 2.00 1.49 2.08 2.27 3.17 

7125 0.25 0.25 0.40 0.40 0.51 0.56 0.61 0.72 0.66 0.80 0.81 1.04 0.87 1.12 0.92 1.20 1.02 1.36 1.12 1.52 1.22 1.68 1.43 2.00 1.49 2.08 2.27 3.17 

7250 0.25 0.25 0.40 0.40 0.50 0.56 0.61 0.72 0.66 0.80 0.81 1.04 0.86 1.12 0.92 1.20 1.02 1.36 1.12 1.52 1.22 1.68 1.43 2.00 1.49 2.08 2.27 3.17 

7375 0.25 0.25 0.40 0.40 0.50 0.56 0.61 0.72 0.66 0.80 0.81 1.04 0.86 1.12 0.92 1.20 1.02 1.36 1.12 1.52 1.22 1.68 1.43 2.00 1.49 2.08 2.27 3.17 

7500 0.25 0.25 0.40 0.40 0.50 0.56 0.61 0.72 0.66 0.80 0.81 1.04 0.86 1.12 0.92 1.20 1.02 1.36 1.12 1.52 1.22 1.68 1.43 2.00 1.49 2.08 2.27 3.17 

Page 5 7/2/96 Test Standards and Calculations 
§85.1 §85.1 

(iii) ASM2525 and ASM5015 Nitric Oxide (% NO) Table 

Column # 41 41 42 42 43 43 44 44 45 45 46 46 47 47 48 48 49 49 50 50 51 51 

ETW 

5015 2525 5015 2525 5015 2525 5015 2525 5015 2525 5015 2525 5015 2525 5015 2525 5015 2525 5015 2525 5015 2525 

1750 1212 1095 1819 1642 2272 2114 2725 2587 3178 3060 3631 3532 4084 4005 4990 4950 4990 4960 4990 4980 4990 4990 

1875 1142 1031 1713 1547 2181 1991 2649 2435 3117 2879 3586 3323 4054 3767 4990 4655 4990 4738 4990 4906 4990 4990 

2000 1077 973 1616 1460 2058 1877 2499 2295 2941 2713 3383 3131 3824 3548 4707 4384 4778 4535 4919 4838 4990 4990 

2125 1018 920 1527 1380 1944 1774 2360 2167 2776 2561 3192 2955 3609 3348 4441 4136 4578 4349 4853 4776 4990 4990 

2250 964 871 1446 1307 1839 1678 2232 2050 2625 2422 3018 2794 3411 3165 4197 3909 4395 4179 4792 4720 4990 4990 

2375 915 827 1372 1240 1744 1592 2115 1943 2487 2295 2859 2646 3231 2998 3974 3701 4228 4024 4736 4668 4990 4990 

2500 869 786 1304 1179 1657 1512 2009 1845 2361 2179 2714 2512 3066 2845 3771 3512 4076 3881 4685 4620 4990 4990 

2625 828 749 1242 1123 1577 1440 1912 1756 2246 2073 2581 2389 2916 2706 3585 3339 3936 3752 4639 4577 4990 4990 

2750 791 715 1186 1072 1504 1374 1823 1675 2142 1976 2460 2277 2779 2579 3416 3181 3809 3579 4596 4374 4990 4772 

2875 756 684 1134 1026 1438 1313 1742 1601 2046 1888 2350 2175 2654 2463 3261 3037 3669 3417 4484 4176 4892 4556 

3000 725 656 1088 984 1378 1258 1668 1533 1959 1808 2249 2082 2539 2357 3120 2906 3510 3270 4290 3996 4680 4359 

3125 696 630 1045 945 1323 1208 1601 1471 1879 1734 2157 1997 2435 2260 2992 2787 3366 3135 4114 3832 4488 4180 

3250 670 607 1006 910 1273 1163 1539 1415 1806 1667 2073 1920 2340 2172 2874 2677 3234 3012 3952 3681 4311 4016 

3375 647 585 970 878 1227 1121 1483 1363 1740 1606 1997 1849 2253 2092 2767 2577 3113 2899 3804 3544 4150 3866 

3500 625 566 937 848 1184 1082 1432 1316 1679 1550 1926 1784 2174 2018 2668 2486 3002 2796 3669 3418 4002 3728 

3625 605 547 907 821 1146 1047 1384 1273 1623 1498 1862 1724 2100 1950 2578 2401 2900 2701 3544 3302 3867 3602 

3750 586 531 879 796 1110 1014 1340 1233 1571 1451 1802 1669 2033 1887 2494 2323 2806 2614 3429 3195 3741 3485 

3875 569 515 853 773 1077 984 1300 1195 1523 1407 1747 1618 1970 1829 2417 2251 2719 2533 3323 3096 3625 3377 

4000 553 501 829 751 1046 956 1262 1161 1479 1365 1695 1570 1912 1775 2345 2184 2638 2457 3224 3003 3517 3276 

4125 538 487 807 731 1017 930 1227 1128 1437 1327 1647 1526 1857 1724 2277 2122 2562 2387 3131 2917 3416 3182 

4250 524 475 786 712 990 905 1194 1098 1398 1291 1602 1484 1806 1677 2214 2063 2490 2320 3044 2836 3321 3094 

4375 510 463 766 694 964 882 1162 1069 1360 1257 1559 1444 1757 1632 2154 2007 2423 2258 2961 2759 3230 3010 

4500 498 451 747 677 939 859 1132 1042 1325 1224 1518 1406 1711 1589 2096 1953 2359 2198 2883 2686 3145 2930 

4625 486 440 728 661 916 838 1104 1015 1291 1193 1479 1370 1666 1548 2042 1903 2297 2140 2807 2616 3063 2854 

4750 474 430 711 645 893 818 1076 990 1259 1163 1441 1336 1624 1508 1989 1854 2238 2085 2735 2549 2983 2780 

4875 463 420 694 630 872 798 1049 966 1227 1134 1405 1302 1583 1470 1938 1806 2180 2032 2665 2483 2907 2709 

5000 452 410 677 615 850 778 1023 942 1196 1106 1369 1269 1542 1433 1889 1760 2125 1980 2597 2420 2833 2640 

5125 441 400 661 600 830 760 998 919 1167 1078 1335 1237 1503 1397 1840 1715 2070 1930 2530 2359 2760 2573 

5250 431 391 646 586 810 741 974 896 1138 1051 1301 1206 1465 1362 1793 1672 2017 1881 2466 2298 2690 2507 

5375 420 382 631 573 790 723 950 874 1109 1025 1269 1176 1428 1327 1747 1629 1966 1833 2403 2240 2621 2443 

5500 410 373 616 559 771 706 926 853 1082 1000 1237 1147 1392 1294 1703 1587 1916 1786 2341 2183 2554 2381 

5625 401 364 601 546 752 689 904 832 1055 975 1206 1118 1357 1261 1659 1547 1867 1740 2282 2127 2489 2321 

5750 391 356 587 534 734 673 882 812 1029 951 1176 1090 1323 1230 1617 1508 1820 1697 2224 2074 2426 2262 

5875 383 348 574 522 717 657 860 793 1004 928 1147 1064 1290 1199 1577 1471 1774 1654 2168 2022 2366 2206 

6000 374 340 561 510 701 642 840 774 980 906 1120 1039 1259 1171 1539 1435 1731 1614 2116 1973 2308 2152 

6125 366 333 549 499 685 628 822 757 958 886 1094 1015 1230 1144 1503 1401 1690 1577 2066 1927 2254 2102 

6250 359 326 538 489 671 615 804 741 937 867 1070 993 1203 1119 1469 1371 1653 1542 2020 1884 2204 2056 

6375 352 320 528 480 658 604 788 727 919 850 1049 973 1179 1096 1439 1343 1619 1510 1979 1846 2159 2014 

6500 346 315 519 473 647 593 775 714 902 835 1030 956 1158 1077 1413 1318 1590 1483 1943 1813 2119 1977 

6625 341 311 512 466 638 585 763 704 889 823 1014 941 1140 1060 1391 1298 1565 1460 1913 1785 2087 1947 

6750 338 307 507 461 631 578 755 696 879 813 1003 931 1127 1048 1374 1283 1546 1443 1890 1764 2062 1924 

6875 335 305 503 458 626 574 749 691 872 807 995 924 1118 1040 1364 1273 1534 1432 1875 1750 2046 1909 

7000 335 305 502 457 624 573 747 689 870 805 992 921 1115 1037 1360 1269 1530 1428 1870 1745 2040 1904 

7125 335 305 502 457 625 573 747 689 870 805 992 921 1115 1037 1360 1269 1531 1428 1874 1745 2045 1904 

7250 335 305 502 457 625 573 747 689 870 805 992 921 1115 1037 1360 1269 1531 1428 1874 1745 2045 1904 

7375 335 305 502 457 625 573 747 689 870 805 992 921 1115 1037 1360 1269 1531 1428 1874 1745 2045 1904 

7500 335 305 502 457 625 573 747 689 870 805 992 921 1115 1037 1360 1269 1531 1428 1874 1745 2045 1904 

Page 6 7/2/96 Test Standards and Calculations 
� 

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§85.1	 §85.1 

(b) Test Score Calculation 

(1)	 Exhaust Gas Measurement Calculation. 

(i)	 Measurement Start. The analysis and recording of exhaust gas concentrations 

shall begin 15 seconds after the applicable test mode begins, or sooner if the 

system response time (to 100%) is less than 15 seconds. The analysis and 

recording of exhaust gas concentrations shall not begin sooner than the time 

period equivalent to the response time of the slowest transducer. 

(ii)	 Sample Rate. Exhaust gas concentrations shall be analyzed at a minimum 

rate of once per second. 

(iii)	 Emission Measurement Calculations. Partial stream (concentration) 

emissions shall be calculated based on a running 10 second average. The 

values used for HC(j), CO(j), and NO(j) are the raw (uncorrected) tailpipe 

concentrations. 

j

 HC(j) * DCF(j) 

j-10 (A) AvgHC = 10 

j

 CO(j) * DCF(j) 

j-10 (B) AvgCO = 10 

j

 NO(j) * DCF(j) 

j-10 (C) AvgNO = 10 

(iv)	 Dilution Correction Factor. The analyzer software shall multiply the raw 

emissions values by the Dilution Correction Factor (DCF) during any valid 

ASM emissions test. The DCF accounts for exhaust sample dilution (either 

intentional or unintentional) during an emissions test. The analyzer software 

shall calculate the DCF using the following procedure, and shall select the 

appropriate vehicle fuel formula. If the calculated DCF exceeds 3.0 then a 

default value of 3.0 shall be used. 

[CO2]measured (A)	 X = [CO2]measured + [CO]measured 

Where [CO2]measured and [CO]measured are the instantaneous 

ASM emissions test readings. 

(B)	 Calculate [CO2]adjusted using the following formulas. 

(1)	 For Gasoline: 

Ø	 X ø [CO2]adjusted = Œ œ o 4.644+1.88X ß

*100 

Page 7	 7/2/96 Test Standards and Calculations 
§85.1	 §85.1 

(2) For Methanol or Ethanol: 

Ø X ø [CO2]adjusted = Œ œ o 4.73+1.88Xß *100 

(3) For Compressed Natural Gas (CNG): 

Ø X ø [CO2]adjusted = Œ œ o 6.64+1.88Xß *100 

(4) For Liquid Propane Gas (LPG): 

Ø X ø [CO2]adjusted = Œ œ o 5.39+1.88Xß *100 

(C) Calculate the DCF using the following formula: 

[CO2]adjusted DCF = [CO2]measured 

(v)	 NO Humidity Correction Factor. The NO measurement shall be adjusted 

based on relative humidity using a correction factor Kh, calculated as follows: 

1

(A)	 Kh = 1 - 0.0047(H-75) 

(B)	 H = Absolute humidity in grains of water per pound of dry air. 

(43.478)Ra*Pd

= PB-(Pd*Ra/100) 

(C)	 Ra = Relative humidity of the ambient air, percent. 

(D)	 Pd = Saturated vapor pressure, mm Hg at the ambient dry bulb 

temperature. If the temperature is above 86_F, then it 

shall be used in lieu of the higher temperature, until EPA 

supplies final correction factors. 

(E)	 PB = Barometric pressure, mm Hg. 

(2)	 Pass/Fail Determination. A pass or fail determination shall be made for each 

applicable test mode based on a comparison of the applicable test standards and the 

measured value for HC, CO, and NO as described in §85.1(b)(1)(iii). A vehicle shall 

pass the test mode if the emission values for HC, CO, and NO are simultaneously 

below or equal to the applicable short test standards for all three pollutants. A 

vehicle shall fail the test mode if the values for HC, CO, or NO, or any combination 

of the three, are above the applicable standards at the expiration of the test time. 

Page 8	 7/2/96 Test Standards and Calculations 
§85.2	 §85.2 

§85.2 Test Procedures 

(a)	 General Requirements. 

(1)	 Vehicle Characterization. The following information shall be determined for the 

vehicle being tested and used to automatically select the dynamometer power 

absorption settings: 

(i)	 Vehicle type: LDGV, LDGT1, LDGT2, HDGT, and others as needed 

(ii)	 Chassis model year 

(iii)	 Make 

(iv)	 Model 

(v)	 Number of cylinders 

(vi)	 Cubic inch or liters displacement of the engine 

(vii)	 Transmission type 

(viii)	 Equivalent Test Weight. 

(2)	 Ambient Conditions. The ambient temperature, absolute humidity, and barometric 

pressure shall be recorded continuously during the test cycle or as a single set of 

readings up to 4 minutes before the start of the driving cycle. 

(3)	 Restart. If shut off, the vehicle shall be restarted as soon as possible before the test 

and shall be running for at least 30 seconds prior to the start of the ASM driving 

cycle. 

(4)	 Void Test Conditions. The test shall immediately end and any exhaust gas 

measurements shall be voided if the instantaneous measured concentration of CO 

plus CO2 falls below six percent or the vehicle's engine stalls at any time during the 

test sequence. 

(5)	 Vehicle Brakes. The vehicle's brakes shall not be applied during the test modes. If 

the vehicles brakes are applied during testing the mode timer shall be reset to zero (tt 

= 0). 

(6)	 Test Termination. The test shall be aborted or terminated upon reaching the overall 

maximum test time. 

(b)	 Vehicle Pre-inspection and Preparation. 

(1)	 Accessories. All accessories (air conditioning, heat, defogger, radio, automatic 

traction control if switchable, etc.) shall be turned off (if necessary, by the inspector). 

(2)	 Exhaust Leaks. The vehicle shall be inspected for exhaust leaks. Audio assessment 

while blocking exhaust flow, or gas measurement of carbon dioxide or other gases 

shall be acceptable. Vehicles with leaking exhaust systems shall be rejected from 

testing. 

Page 9	 7/2/96 Test Procedures 
§85.2	 §85.2 

(3)	 Fluid Leaks. The vehicle shall be inspected for fluid leaks. Vehicles with leaking 

engine oil, transmission fluid, or coolant shall be rejected from testing. 

(4)	 Mechanical Condition. Vehicles with obvious mechanical problems (engine, 

transmission, brakes, or exhaust) that either create a safety hazard or could bias test 

results shall be rejected from testing. 

(5)	 Operating Temperature. The vehicle shall be at normal operating temperature prior 

to the start of the test. The vehicle temperature gauge, if equipped and operating, 

shall be checked to assess temperature. Vehicles in overheated condition shall be 

rejected from testing. 

(6)	 Tire Condition. Vehicles shall be rejected from testing if tread indicators, tire cords, 

bubbles, cuts, or other damage are visible. Vehicles shall be rejected from testing if 

they have space-saver spare tires or if they do not have reasonably sized tires on the 

drive axle or axles. Vehicles may be rejected if they have different sized tires on the 

drive axle or axles. In test-and-repair facilities, drive wheel tires shall be checked 

with a gauge for adequate tire pressure. In test-only facilities, drive wheel tires shall 

be visually checked for adequate pressure level. Drive wheel tires that appear low 

shall be inflated to approximately 30 psi, or to tire side wall pressure, or vehicle 

manufacturer's recommendation. Alternatively, vehicles with apparent low tire 

pressure may be rejected from testing. 

(7)	 Gear Selection. The vehicle shall be operated during each mode of the test with the 

gear selector in drive for automatic transmissions and in second (or third if more 

appropriate) for manual transmissions for the loaded modes. 

(8)	 Roll Rotation. The vehicle shall be maneuvered onto the dynamometer with the 

drive wheels positioned on the dynamometer rolls. Prior to test initiation, the rolls 

shall be rotated until the vehicle laterally stabilizes on the dynamometer. Vehicles 

that cannot be stabilized on the dynamometer shall be rejected from testing. Drive 

wheel tires shall be dried if necessary to prevent slippage.

 (9)	 Vehicle Restraint. Testing shall not begin until the vehicle is restrained. Any 

restraint system shall meet the requirements of §85.3(a)(5)(ii). In addition, the 

parking brake shall be set for front wheel drive vehicles prior to the start of the test, 

unless parking brake functions on front axle or if is automatically disengaged when 

in gear. 

(10)	 Vehicle Conditioning. 

(i)	 Queuing Time. When a vehicle waits in a queue more than 20 minutes or 

when a vehicle is shut-off for more than 5 minutes prior to the test, vehicle 

conditioning shall be performed for 60 seconds, as specified in 

§85.2(b)(10)(ii)(C). Emissions may be monitiored during this cycle and if 

passing readings are obtained, as specified for the ASM cycle in §85.2(d), 

then the cycle may be terminated and the respective ASM mode skipped. 

Page 10	 7/2/96 Test Procedures 
§85.2	 §85.2 

(ii)	 Discretionary Preconditioning. At the program's discretion, any vehicle may 

be preconditioned using any of the following methods: 

(A)	 Non-loaded Preconditioning. Increase engine speed to approximately 

2500 rpm, for up to 4 minutes, with or without a tachometer. 

(B)	 Loaded Preconditioning. Drive the vehicle on the dynamometer at 30 

miles per hour for up to 240 seconds at road-load. 

(C)	 ASM Preconditioning. Drive the vehicle on the dynamometer using 

either mode of the ASM test as specified in §85.2(d). 

(D)	 Transient Preconditioning. After maneuvering the vehicle onto the 

dynamometer, drive a transient cycle consisting of speed, time, 

acceleration, and load relationships such as the IM240. 

(c)	 Equipment Preparation and Settings. 

(1)	 Analyzer Warm-Up. Emission testing shall be locked out until the analyzer is 

warmed-up and stable. The analyzer shall reach stability within 30 minutes from 

startup. If an analyzer does not achieve stability within the allotted time frame, it 

shall remain locked out from testing. The instrument shall be considered "warmedup" when the zero and span readings for HC, CO, NO, and CO2 have stabilized 

within the accuracy values specified in §85.3(c)(3) for five minutes without 

adjustment (this does not require span gas verification of warm-up, but provides the 

quality assurance method for checking). 

(2)	 Emission Sample System Purge. While a lane is in operation, the sample system 

shall be continuously purged after each test for at least 15 minutes if not taking 

measurements. 

(3)	 Probe Insertion. The sample probe shall be inserted into the vehicle's tailpipe to a 

minimum depth of 10 inches. If the vehicle's exhaust system prevents insertion to 

this depth, a tailpipe extension shall be used. 

(4)	 Multiple exhaust pipes. Exhaust gas concentrations from vehicle engines equipped 

with functionally independent multiple exhaust pipes shall be sampled 

simultaneously. 

(5)	 Analyzer Preparation. The analyzer shall perform an automatic zero, an ambient air 

reading, and an HC hang-up check prior to each test. This process shall occur within 

two minutes of the start of the test. 

(i)	 Automatic Gas Zero. The analyzer shall conduct automatic zero adjustments 

using the zero gas specified in §85.4(d)(2)(iii). The zero adjustment shall 

include the HC, CO, CO2, and NO channels. Bottled or generated zero air 

may be used. 

Page 11	 7/2/96 Test Procedures 
§85.2	 §85.2 

(ii)	 Ambient Air Reading. Filtered ambient air shall be introduced to the 

analyzer before the sample pump, but after the sample probe, hose, and 

filter/water trap. The analyzer shall record the concentrations of the four 

measured gases, but shall make no adjustments. 

(iii)	 HC Hang-up Determination. The analyzer shall sample ambient air through 

the probe to determine background pollution levels and HC hang-up. The 

analyzer shall be locked out from testing until (1) the sample through probe 

has less than 15 ppm HC, 0.02% CO, and 25 ppm NO; and, (2) the residual 

HC in the sampling system (probe sample - ambient air reading) is less than 7 

ppm. 

(6)	 Cooling System. When ambient temperatures exceed 72°F, testing shall not begin 

until the cooling system blower is positioned and activated. The cooling system 

blower shall be positioned to direct air to the vehicle cooling system, but shall not be 

directed at the catalytic converter. 

(7)	 Dynamometer Warm-Up. The dynamometer shall be automatically warmed-up prior 

to official testing and shall be locked out until it is warmed-up. Dynamometers 

resting (not operated for at least 30 seconds and at least 15 mph) for more than 30 

minutes shall pass the coast-down check specified in §85.4(b)(1) prior to use in 

testing. As specified in §85.4(a)(2), control charts may be used to demonstrate 

allowing a longer duration of inactivity before a required warm-up. 

(8)	 Load Setting. Prior to each mode, the system shall automatically select the load 

setting of the dynamometer from a look-up table supplied by EPA or the state. 

(9)	 Engine Speed. Engine speed measurement equipment shall be attached on all 1996 

and newer light duty vehicles and trucks, and in test-and-repair programs, engine 

speed shall also be monitored on all pre-1996 vehicles. Starting in 1998, the SAEstandardized OBD plug shall be used on 1996 and newer vehicles. Engine speed 

measurement equipment shall meet the requirements of §85.3(c)(5). 

(d)	 Test Procedures. 

The test sequence shall consist of either a single ASM mode or both ASM modes described 

in §85.2(d)(1) and (2), and may be performed in either order (with appropriate chnage in 

transition requirements in §85.2(d)(1)(iv)). Vehicles that fail the first-chance test described 

in §85.2(d) shall receive a second-chance test if the conditions in §85.2(e) apply. The test 

timer shall start (tt=0) when the conditions specified in §85.2(c)(2) and §85.2(c)(3) are met 

and the mode timer initiates as specified in §85.2(d)(1) or §85.2(d)(2). The test sequence 

shall have an overall maximum test time of 290 seconds (tt=290). The test shall be 

immediately terminated or aborted upon reaching the overall maximum test time. 

(1)	 ASM5015 Mode. 

(i)	 The mode timer shall start (mt=0) when the dynamometer speed (and 

corresponding power) is maintained within 15±1.0 miles per hour for 5 

continuous seconds. If the inertia simulation error exceeds the tolerance 

specified in §85.3(a)(4)(ii)(A) (or §85.3(a)(4)(ii)(B) if used) for more than 3 

consecutive seconds after the mode timer is started, the test mode timer shall 

Page 12	 7/2/96 Test Procedures 
§85.2	 §85.2 

be set to mt=0. Should this happen a second time, the test shall be aborted. 

The dynamometer shall apply the correct torque for 15.0 mph for the torque 

at any testing speed within the tolerance of 15±1.0 miles per hour (i.e., 

constant torque load over speed range). The torque tolerance shall be ± 5% 

of the correct torque at 15 mph. 

(ii)	 The dynamometer power shall be automatically selected from an EPAsupplied or EPA-approved look-up table, based upon the vehicle 

identification information described in §85.2(a)(1). Vehicles not listed in the 

look-up table and for which ETW is not available shall be tested using the 

following default settings: 

Default ASM5015 Actual Horsepower Settings 

For 8.6" Dynamometers HP50158 

fl Vehicle Type 

Number of Cylindersfi 3 4 5 & 6 8 > 8 

Sedans 

Station Wagons 

Mini-vans 

Pickup Trucks 

Sport/Utility 

Full Vans 

7.9 

8.1 

10.2 

9.6 

10.1 

10.3 

11.4 

11.7 

14.1 

13.1 

13.4 

13.9 

13.8 

13.8 

15.8 

16.4 

15.5 

17.7 

16.4 

16.1 

17.9 

19.2 

19.4 

19.6 

16.0 

16.1 

18.2 

21.1 

21.1 

20.5 

Default ASM5015 Actual Horsepower Settings
 

For 20" Dynamometers HP501520
 

fl Vehicle Type 

Number of Cylindersfi 3 4 5 & 6 8 > 8 

Sedans 

Station Wagons 

Mini-vans 

Pickup Trucks 

Sport/Utility 

Full Vans 

8.1 

8.3 

10.4 

9.8 

10.5 

10.8 

11.8 

12.1 

14.5 

13.4 

13.8 

14.4 

14.3 

14.2 

16.3 

16.8 

15.9 

18.2 

16.9 

16.6 

18.5 

19.8 

19.9 

20.2 

16.6 

16.6 

18.7 

21.7 

21.7 

21.1 

If the dynamometer speed or torque falls outside the speed or torque tolerance 

for more than 2 consecutive seconds, or for more than 5 seconds total, the 

mode timer shall reset to zero and resume timing. The minimum mode length 

shall be determined as described in §85.2(d)(iii). The maximum mode length 

shall be 90 seconds elapsed time (mt=90). 

During the 10 second period used for the pass decision, the dynamometer 

speed shall not fall more than 0.5 mph (absolute drop, not cumulative). If the 

speed at the end of the 10 second period is more than 0.5 mph less than the 

speed at the start of the 10 second period, testing shall continue until the 

speed stabilizes enough to meet this criterion. 

Page 13	 7/2/96 Test Procedures 
§85.2	 §85.2 

The ten second emissions window shall be matched to the corresponding 

vehicle speed trace time window. This shall be performed by subtracting the 

nominal response time for the analyzers from the mode time to determine the 

time for the corresponding vehicle speed. 

(iii)	 The pass/fail analysis shall begin after an elapsed time of 25 seconds 

(mt=25). A pass or fail determination shall be made for the vehicle and the 

mode shall be terminated as follows: 

(A)	 The vehicle shall pass the ASM5015 mode and the mode shall be 

immediately terminated if, at any point between an elapsed time of 25 

seconds (mt=25) and 90 seconds (mt=90), the 10 second running 

average measured values for each pollutant are simultaneously less than 

or equal to the applicable test standards described in §85.1(a). 

(B)	 The vehicle shall fail the ASM5015 mode and the mode shall be 

terminated if the requirements of §85.2(d)(1)(iii)(A) are not satisfied by 

an elapsed time of 90 seconds (mt=90). 

(iv)	 Upon termination of the ASM5015 mode, the vehicle shall immediately 

begin accelerating to the speed required for the ASM2525 mode. The 

dynamometer torque shall smoothly transition during the acceleration period 

and shall automatically reset to the load required for the ASM2525 mode as 

specified in §85.2(d)(2)(i) once the roll speed specified in §85.2(d)(2)(i) is 

achieved. 

(2)	 ASM2525 Mode. 

(i)	 The mode timer shall start (mt=0) when the dynamometer speed (and 

corresponding power) are maintained within 25±1.0 miles per hour for 5 

continuous seconds. If the inertia simulation error exceeds the tolerance 

specified in §85.3(a)(4)(ii)(A) (or §85.3(a)(4)(ii)(B) if used) for more than 3 

consecutive seconds after the mode timer is started, the test mode timer shall 

be set to mt=0. Should this happen a second time, the test shall be aborted. 

The dynamometer shall apply the correct torque for 25.0 mph for the torque 

at any testing speed within the tolerance of 25±1.0 miles per hour (i.e., 

constant torque load over speed range). The torque tolerance shall be ± 5% 

of the correct torque at 25 mph. 

(ii)	 The dynamometer power shall be automatically selected from an EPAsupplied or EPA-approved look-up table, based upon the vehicle 

identification information described in §85.2(a)(1). Vehicles not listed in the 

look-up table and for which ETW is not available shall be tested using the 

following default settings: 

Page 14	 7/2/96 Test Procedures 
§85.2	 §85.2 

Default ASM2525 Actual Horsepower Settings 

For 8.6" Dynamometers HP25258 

fl Vehicle Type 

Number of Cylindersfi 3 4 5 & 6 8 > 8 

Sedans 

Station Wagons 

Mini-vans 

Pickup Trucks 

Sport/Utility 

Full Vans 

6.7 

6.8 

8.8 

8.0 

8.8 

9.0 

9.5 

9.7 

11.7 

10.9 

11.2 

11.6 

11.5 

11.5 

13.2 

13.6 

12.9 

14.7 

13.7 

13.4 

14.9 

16.0 

16.1 

16.3 

13.3 

13.3 

15.3 

17.8 

17.8 

17.2 

Default ASM2525 Actual Horsepower Settings
 

For 20" Dynamometers HP252520
 

fl Vehicle Type 

Number of Cylindersfi 3 4 5 & 6 8 > 8 

Sedans 

Station Wagons 

Mini-vans 

Pickup Trucks 

Sport/Utility 

Full Vans 

6.9 

7.0 

8.9 

8.1 

8.9 

9.1 

10.1 

10.4 

12.5 

11.4 

11.8 

12.5 

12.3 

12.2 

14.0 

14.4 

13.6 

15.5 

14.5 

14.2 

15.9 

16.9 

17.1 

17.3 

14.3 

14.4 

16.3 

18.8 

18.8 

18.3 

If the dynamometer speed or torque falls outside the speed or torque tolerance 

for more than two consecutive seconds, or for more than 5 seconds total, the 

mode timer shall reset to zero and resume timing. The minimum mode length 

shall be determined as described in §85.2(d)(2)(iii). The maximum mode 

length shall be 90 seconds elapsed time (mt=90). 

During the 10 second period used for the pass decision, the dynamometer 

speed shall not fall more than 0.5 mph (absolute drop, not cumulative). If the 

speed at the end of the 10 second period is more than 0.5 mph less than the 

speed at the start of the 10 second period, testing shall continue until the 

speed stabilizes enough to meet this criterion. 

(iii)	 The pass/fail analysis shall begin after an elapsed time of 25 seconds 

(mt=25). A pass or fail determination shall be made for the vehicle and the 

mode shall be terminated as follows: 

(A)	 The vehicle shall pass the ASM2525 mode if, at any point between an 

elapsed time of 25 seconds (mt=25) and 90 seconds (mt=90), the 10­

second running average measured values for each pollutant are 

simultaneously less than or equal to the applicable test standards 

described in §85.1(a). If the vehicle passed the ASM5015 mode, as 

described in §85.2(d)(1)(iii), the ASM2525 mode shall be terminated 

upon obtaining passing scores for all three pollutants. If the vehicle 

Page 15	 7/2/96 Test Procedures 
§85.2	 §85.2 

failed the ASM5015 mode, the ASM2525 mode shall continue for an 

elapsed time of 90 seconds (mt=90). 

(B)	 The vehicle shall fail the ASM2525 mode and the mode shall be 

terminated if the requirements of §85.2(d)(2)(iii)(A) are not satisfied by 

an elapsed time of 90 seconds (mt=90). 

(e)	 Second Chance Tests. 

(1)	 If the vehicle fails the first-chance test, the test timer shall reset to zero (tt=0) and a 

second-chance test shall be performed, except as noted below. The second-chance 

test shall have an overall maximum test time of 145 seconds (tt=145) if one mode is 

repeated, an overall maximum time of 290 seconds (tt=290) if two modes are 

repeated. 

(2)	 Repetition or extension of failed modes for two mode ASM tests. Except in the case 

of vehicles subject to preconditioning specified in §85.2(b)(10(i), if at least 90 

seconds of loaded preconditioning is performed, as specified in §85.2(b)(10)(ii), then 

the second-chance test may be omitted. 

(i)	 If the vehicle failed only the first mode (ASM5015) of the first chance test, 

then that mode shall be repeated upon completion of the second mode 

(ASM2525). The repeated mode shall be performed as described in 

§85.2(d)(1) except that the provisions of §85.2(d)(1)(iv) shall be omitted. 

The test will terminate when the mode ends or when the vehicle passes, 

whichever occurs first. 

(ii)	 If the vehicle is failing only the second mode (ASM2525) of the first chance 

test, then the second mode shall not end at 90 seconds but shall continue for 

up to 180 seconds. Mode and test timers shall not reset but rather continue 

up to 180 seconds. The provisions of §85.2(d)(2) shall continue to apply 

throughout the 180 second test period. 

(iii)	 If the vehicle failed both modes (ASM5015 and ASM2525) of the first 

chance test, then the vehicle shall receive a second-chance test for the 

ASM5015. If the vehicle fails the second-chance ASM5015, then the vehicle 

shall fail the test. Otherwise, the vehicle shall also receive a second-chance 

ASM2525. 

(3)	 Repetition of failed modes for single mode ASM tests. 

(ii)	 If the vehicle is failing at the end of the mode then the test mode shall not end 

at 90 seconds but shall continue for up to 180 seconds. Mode and test timers 

shall not reset but rather continue up to 180 seconds. The provisions of 

§85.2(d)(1) or §85.2(d)(2) shall continue to apply throughout the 180 second 

test period. 

Page 16	 7/2/96 Test Procedures 
§85.3	 §85.3 

§85.3 Test Equipment Specifications 

(a)	 Dynamometer Specifications. 

(1)	 General Requirements 

(i)	 Only one diameter of dynamometer shall be used in a program. 

(ii)	 The dynamometer structure (e.g., bearings, rollers, pit plates, etc.) shall 

accommodate all light-duty vehicles and light-duty trucks up to 8500 pounds 

GVWR. 

(iii)	 Dynamometer ASM load horsepower (HP5015 or HP2525) shall be 

automatically selected based on the vehicle parameters in the test record. 

(iv)	 All dynamometers shall have an identification plate permanently affixed 

showing at a minimum, the dynamometer manufacturers name, the system 

provider's name, production date, model number, serial number, 

dynamometer type, maximum axle weight, maximum HP absorbed, roll 

diameter, roll width, base inertia weight, and electrical requirements. 

(v)	 Alternative dynamometer specifications or designs may be allowed if 

proposed by a state and upon a determination by the Administrator that, for 

the purpose of properly conducting an approved short test, the evidence 

supporting such deviations show that proper vehicle loading will be applied. 

(2)	 Power Absorption. 

(i)	 Vehicle Loading. The vehicle loading used during the ASM driving cycles 

shall follow the equation in §85.3(a)(2)(ii) at 15 and 25 mph. Unless 

otherwise noted, any horsepower displayed during testing shall be expressed 

as HP. 

(ii)	 IHP = THP - PLHP - GTRL 

HP = IHP + PLHP 

Where: 

HP = The actual Horsepower value contained in the look-up table for a 

vehicle being tested (using the ASM5015 or 2525) on a 

dynamometer with the specified diameter rollers. The actual 

horsepower is the sum of the indicated horsepower and the 

parasitic losses (PLHP) 

IHP = Indicated Horsepower value set on the dynamometer. 

THP = Total Horsepower for an ASM test includes indicated, tire losses, 

and parasitics. This value is independent of roll size. 

GTRL = Generic Tire/Roll Interface Losses at the specified speed (15 or 

25 mph) on a dynamometer with the specified diameter rollers. 

Page 17	 7/2/96 Test Equipment Specifications 
§85.3 §85.3 

PLHP = Parasitic Losses Horsepower due to internal dynamometer 

friction. A value is specific to each individual dynamometer and 

speed. 

(iii) Range of Power Absorber. The range of the power absorber shall be 

sufficient to simulate the load required to perform an ASM5015 and an 

ASM2525 on all light-duty vehicles and light-duty trucks up to 8500 pounds 

GVWR. The power absorber shall absorb, at 14 mph and above, a minimum 

of 25 horsepower continuously for a steady-state test of at least 5 minutes, 

with 3 minutes between each test. 

(iv) Parasitic Losses. The parasitic losses (PLHP) in each dynamometer system 

(including but not limited to windage, bearing friction, and system drive 

friction) shall be characterized at 15 and 25 mph upon initial acceptance, and 

during each dynamometer calibration. The parasitic power losses shall be 

determined as indicated in §85.4(b)(2). 

(v) Power Absorber. Only electric power absorbers shall be used unless 

alternatives are proposed by the state and approved by the Administrator. 

The power absorber shall be adjustable in 0.1 hp increments at both 15 MPH 

and 25 MPH. The accuracy of the power absorber (PAU + parasitic losses) 

shall be ±0.25 horsepower or ±2% of required power, whichever is greater, in 

either direction of rotation. For field auditing the accuracy shall be ±0.5 

horsepower. 

(vii) Accuracy Over the Operating Range. The dynamometer's accuracy when 

warm shall not deviate more than ±0.5 horsepower over the full ambient 

operating range of 35°F to 110°F. This may be accomplished by intrinsic 

design or by software correction techniques. At any constant temperature, 

the dynamometer shall have an accuracy of ±0.5 horsepower within 15 

seconds of the start of the test, and shall have an accuracy of ±0.25 

horsepower within 30 seconds of the start of the test. For temperatures 

outside the specified range, the dynamometer shall provide correction or 

proceed with a manufacturer warm-up sequence until full warm condition has 

been reached. 

(3) Rolls. 

(i) Size and Type. The dynamometer shall be equipped with twin rolls. The 

rolls shall be electrically or mechanically coupled side-to-side and front-torear. The dynamometer roll diameter shall be between 8.5 and 21.0 inches. 

The spacing between the roll centers shall comply with the equation in 

§85.3(a)(3)(ii) to within 0.5 inches and -0.25 inches of the calculated value. 

Fixed dynamometer rolls shall have an inside track width of no more than 30 

inches and outside track width of at least 100 inches. Rolls moveable from 

side-to-side may be used if adequate measures are taken to prevent tire 

damage from lateral vehicle movement and the dynamometer sufficiently 

accommodates track widths of the full range of vehicles to be tested on the 

dynamometer. Alternative track widths, roll sizes, and number of rolls may 

Page 18 7/2/96 Test Equipment Specifications 
§85.3 §85.3 

be used if approved by the state and the Administrator and if adequate 

measures are taken to prevent tire damage from lateral vehicle movement and 

the dynamometer sufficiently accommodates track widths of the full range of 

vehicles to be tested on the dynamometer. 

(ii) Roll Spacing = (24.375+D) * Sin 31.5153 

D = dynamometer roll diameter. 

Roll spacing and roll diameter are expressed in inches. 

(iii) Design. The roll size, surface finish, and hardness shall be such that tire 

slippage is minimized under all weather conditions; that water removal is 

maximized; that the specified accuracy of the distance and speed 

measurements are maintained; and that tire wear and noise are minimized. 

(4) Inertia. 

(i) Base Inertia. The dynamometer shall be equipped with mechanical 

flywheel(s) or with full inertia simulation providing a total base inertia weight 

of 2000 pounds ±40 pounds. Any deviation from the 2000 pound base inertia 

shall be quantified and the coast-down time shall be corrected accordingly. 

Any deviation from the stated inertia shall be quantified and the inertia 

simulation shall be corrected accordingly. The actual inertia weight shall be 

marked on the ID plate required in §85.3(a)(1)(iv). 

(ii) Inertia/Inertia Simulation. The dynamometer shall be capable of conducting, 

at a minimum, diagnostic level transient inertia simulations with an 

acceleration rate between 0 and 3.3 miles per hour per second with a 

minimum load (power) of 25 horsepower at 14 mph over the inertia weight 

range of 2000 pounds to 6000 pounds. For the diagnostic level inertia 

simulation, the 25 horsepower criterion is a requirement on acceleration only, 

while for the full inertia simulation option, the requirement is for both 

acceleration and deceleration. Mechanical inertia simulation shall be 

provided in 500 pound increments; electric inertia simulation shall be 

provided in 1 pound increments. Any deviation from the stated inertia shall 

be quantified and the inertia simulation shall be corrected accordingly. 

Mechanical or electrical inertia simulation, or a combination of both, may be 

used, subject to review and approval by the state. 

(A) Diagnostic Level Simulation. 

1. System Response. The torque response to a step change shall be 

at least 90% of the requested change within 300 milliseconds. 

2. Simulation Error. An inertia simulation error (ISE) shall be 

continuously calculated any time the actual dynamometer speed is 

between 10 MPH and 60 MPH. The ISE shall be calculated by the 

Page 19 7/2/96 Test Equipment Specifications 
 

§85.3	 §85.3 

equation in §85.3(a)(4)(ii)(C), and shall not exceed 3% of the 

inertia weight selected (IWs) for the vehicle under test. 

(B)	 Full Inertia Simulation. (Recommended Option) 

1.	 System Response. The torque response to a step change shall be 

at least 90% of the requested change within 100 milliseconds after 

a step change is commanded by the dynamometer control system, 

and shall be within 2% of the commanded torque by 300 

milliseconds after the command is issued. Any overshoot of the 

commanded torque value shall not exceed 25% of the torque 

value. 

2.	 Simulation Error. An inertia simulation error (ISE) shall be 

continuously calculated any time the actual dynamometer speed is 

between 10 MPH and 60 MPH. The ISE shall be calculated by the 

equation in §85.3(a)(4)(ii)(C), and shall not exceed 1% of the 

inertia weight selected (IWs) for the vehicle under test. 

(C)	 Inertia Simulation Error Calculation. 

ISE = [(IWs - It) / (IWs)] * 100 

( 1) It = Im + Jt (Fm - Frl) dt ŁVł ı0 

Where: 

ISE = Inertia Simulation Error 

IWs = Inertia Weight Selected 

It = Total inertia being simulated by the dynamometer 

(kg) 

It (lb force) = It (kg) * 2.2046 

Im = Base (mechanical inertia of the dynamometer (kg) 

V = Measured roll speed (m/s) 

Fm = Force measured by the load cell (translated to the roll 

surface) (N) 

Frl = Road load force (N) required by IHP at the measure 

roll speed (V) 

t = Time (sec) 

(5)	 Other Requirements. 

(i)	 Vehicle Speed. The measurement of roll speed shall be accurate within 0.1 

mph over the full operating range. The dynamometer shall accommodate 

vehicle speeds of up to 60 mph. 

(ii)	 Vehicle Restraint. The vehicle shall be restrained during the driving cycle. 

The restraint system shall be designed to insure that vertical and horizontal 

Page 20	 7/2/96 Test Equipment Specifications 
§85.3	 §85.3 

force on the drive wheels does not significantly affect emission levels. The 

restraint system shall allow unobstructed vehicle ingress and egress and shall 

be capable of safely restraining the vehicle under all reasonable operating 

conditions without damaging the suspension system. 

(iii)	 Vehicle Cooling. The test system shall provide for a method to prevent 

overheating of the vehicle. The test shall be conducted with the hood open 

and the cooling system activated when ambient temperature exceeds 72°F. 

The cooling method used shall direct air to the test vehicle's cooling system. 

The cooling system capacity shall be at least 3000 SCFM within 12 inches of 

the intake to the vehicle's cooling system. The cooling system shall avoid 

improper cooling of the catalytic converter. 

(iv)	 Four-Wheel Drive. If used, four-wheel drive dynamometers shall insure the 

application of correct vehicle loading as defined in §85.3(a)(2), shall not 

damage the four wheel drive system of the vehicle, and shall accomodate 

vehicles equipped with anti-lock brakes and/or traction control. Front and 

rear wheel rolls shall maintain speed synchronization within 0.2 mph. 

(v)	 Installation. Either in-floor or above ground installations of the dynamometer 

are acceptable. In all cases, installation must be performed so that the test 

vehicle is approximately level (±5°) while on the dynamometer during 

testing. 

(vi)	 Augmented Braking. Dynamometers shall apply augmented braking on 

major decelerations during transient drive cycles, if such cycles are used in 

the program. The dynamometer software shall provide a signal output to 

inform the operator when augmented braking is activated. 

(b)	 Emission Sampling System. 

(1)	 The sampling system shall be designed to insure durable, leak free operation and be 

easily maintained. Materials that are in contact with the gases sampled shall not 

contaminate or change the character of the gases to be analyzed, including gases 

from vehicles not fueled by gasoline (except diesels). The system shall be designed 

to be corrosion-resistant and be able to withstand typical vehicle exhaust 

temperatures when the vehicle is driven through the ASM test cycle for 290 seconds. 

(2)	 The sampling system shall draw exhaust gas from the vehicle, shall remove 

particulate matter and aerosols from the sampled gas, shall drain condensed water 

from the sample if necessary, and shall deliver the resultant gas sample to the 

analyzers/sensors for analysis and then deliver the analyzed sample directly outside 

the building. The sampling system shall, at a minimum, consist of a tailpipe probe, 

flexible sample line, water removal system, a particulate trap, sample pump, and 

flow control components. 

Page 21	 7/2/96 Test Equipment Specifications 
§85.3 §85.3 

(3) Sample Probe. 

(i) Insertion. The sample probe shall allow at least a 16 inch insertion depth of 

the sample point into the vehicle's exhaust. In addition, the probe shall be 

inserted at least 10 inches into the vehicle's exhaust. Use of a tailpipe 

extension is permitted as long as the extension does not change the exhaust 

back pressure by more than ±1.0 inch of water pressure. 

(ii) Retention. The probe shall incorporate a positive means of retention to 

prevent it from slipping out of the tailpipe during use. High through-put test 

systems may use alternative means to insure probe retention. 

(iii) Flexibility. The probe shall be designed so that the tip extends 16 inches into 

the tailpipe. The probe tip shall be shielded so that debris is not scooped up 

by the probe when it is inserted into the tailpipe. High through-put test 

systems may use alternative means to insure adequate probe insertion. 

(iv) Probe Tip. 

dilution. 

Probe tips shall be designed and constructed to prevent sample 

(v) Materials. All materials in contact with exhaust gas prior to and throughout 

the measurement portion of the system shall be unaffected by and shall not 

affect the sample (i.e., the materials shall not react with the sample, and they 

shall not taint the sample). Acceptable materials include stainless steel, 

Teflon, silicon rubber, and Tedlar. Dissimilar metals with thermal expansion 

factors of more than 5% shall not be used in either the construction of probes 

or connectors. The sample probe shall be constructed of stainless steel or 

other non-corrosive, non-reactive material which can withstand exhaust gas 

temperatures at the probe tip of up to 1,100_F for 10 minutes. 

(vi) System Hoses and Connections. Hoses and all other sample handling 

components must be constructed of, or plated with a non-reactive, noncorrosive, high temperature material which will not affect, or be affected by, 

the exhaust constituents and tracer gases. 

(vii) Dual Exhaust. The sample system shall provide for the testing of dual 

exhaust equipped vehicles. When testing a vehicle with functional dual 

exhaust pipes, a dual sample probe of a design certified by the analyzer 

manufacturer to provide equal flow in each leg shall be used. The equal flow 

requirement is considered to be met if the flow rate in each leg of the probe 

has been measured under two sample pump flow rates (the normal rate and a 

rate equal to the onset of low flow), and if the flow rates in each of the legs 

are found to be equal to each other (within 15% of the flow rate in the leg 

having lower flow). 

(4) Particulate Filter. The particulate filter shall be capable of trapping 97% of all 

particulate and aerosols 5 microns or larger. The filter element shall not absorb or 

adsorb hydrocarbons. The filter housing shall be transparent or translucent to allow 

the operator to observe the filter element’s condition without removing the housing. 

Page 22 7/2/96 Test Equipment Specifications 
§85.3	 §85.3 

The filter element shall be easily replaceable and shall provide for reliable sealing 

after filter element changes. 

(5)	 Water Trap. The water trap shall be sized to remove exhaust sample water from 

vehicles fueled with gasoline, propane, compressed natural gas, reformulated 

gasoline, alcohol blends or neat, and oxygenated fuels. The filter element, bowl and 

housing shall be inert to these fuels as well as to the exhaust gases from vehicles 

burning these fuels. The condensed water shall be drained from the water trap’s 

bowl either continuously or automatically on a periodic basis such that the following 

performance requirement is maintained. Sufficient water shall be trapped, regardless 

of fuel, to prevent condensation in the sample system or in the optical bench’s 

sample cell. 

(6)	 Low Flow Indication. The analyzer shall lock out official testing when the sample 

flow is below the acceptable level. The sampling system shall be equipped with a 

flow meter (or equivalent) that shall indicate sample flow degradation when 

measurement error exceeds 3% of the gas value used for checking, or causes the 

system response time to exceed 13 seconds to 90 percent of a step change in input 

(excluding NO), whichever is less. 

(7)	 Exhaust Ventilation System. The high quantities of vehicle emissions generated 

during loaded mode testing shall be properly vented to prevent buildup of hazardous 

concentrations of HC, CO, CO2 and NOx. Sufficient ventilation shall be provided in 

the station to maintain HC, CO, CO2 and NO levels below OSHA standards. 

(i)	 The ventilation system shall discharge the vehicle exhaust outside the 

building. 

(ii)	 The flow of the exhaust collection system shall not cause dilution of the 

exhaust at the sample point in the probe. 

(iii)	 The flow of the exhaust collection system shall not cause a change of more 

than ±1.0 inches of water pressure in the vehicle's exhaust system at the 

exhaust system outlet. 

(c)	 Analytical Instruments. 

(1)	 General Requirements. 

(i)	 Measured Gases. The analyzer system shall consist of analyzers for HC, CO, 

NO, and CO2, (O2 optional) and digital displays for exhaust concentrations 

of HC, CO, NO, and CO2, and for vehicle speed. 

(ii)	 Emission Accuracy. The system shall ensure that the analytical system 

provides an accurate accounting of the actual exhaust emissions produced 

during the test, taking into consideration the individual channel accuracies, 

repeatabilities, interference effects, sample transport times, and analyzer 

response times. 

Page 23	 7/2/96 Test Equipment Specifications 
§85.3	 §85.3 

(iii)	 Sample Rate. The analyzer shall be capable of measuring exhaust 

concentrations of the gases specified in §85.3(c)(1)(i) at a minimum rate of 

once per second. 

(iv)	 Alternative Equipment. Alternative analytic equipment specification, 

materials, designs, or detection methods may be allowed if proposed by a 

state and upon a determination by the Administrator, that for the purpose of 

properly conducting a test, the evidence supporting such deviations will not 

significantly affect the proper measurement of emissions. 

(2)	 Performance Requirements. 

(i)	 Temperature Operating Range. The analyzer system and all associated 

hardware shall operate within the performance specifications described in 

§85.3(c)(3) at ambient air temperatures ranging from 35_F to 110_F. 

Analyzers shall be designed so that adequate air flow is provided around 

critical components to prevent overheating (and automatic shutdown) and to 

prevent the condensation of water vapor which could reduce the reliability 

and durability of the analyzer. The analyzer system shall otherwise include 

necessary features to keep the sampling system within the specified range. 

(ii)	 Humidity Operating Range. The analyzer system and all associated hardware 

shall operate within the performance specifications described in §85.3(c)(3) 

at a minimum of 85% relative humidity throughout the required temperature 

range. 

(iii)	 Interference Effects. The interference effects for non-interest gases shall not 

exceed ±4 ppm for hydrocarbons, ±0.02% for carbon monoxide, ±0.20% for 

carbon dioxide, and ±20 ppm for nitric oxide when using the procedure 

specified in §85.4(d)(5)(iv). Corrections for collision-broadening effects of 

combined high CO and CO2 concentrations shall be taken into account in 

developing the factory calibration curves, and are included in the accuracy 

specifications. 

(iv)	 Barometric Pressure Compensation. Barometric pressure compensation shall 

be provided. Compensation shall be made for elevations up to 6000 feet 

(above mean sea level). At any given altitude and ambient conditions 

specified in §85.3(c)(2)(i) and (ii), errors due to barometric pressure changes 

of ±2 inches of mercury shall not exceed the accuracy limits specified in 

§85.3(c)(3). 

(v)	 System Lockout During Warm-up. Functional operation of the gas sampling 

unit shall remain disabled through a system lockout until the instrument 

meets stability and warm-up requirements. The instrument shall be 

considered "warm" when the zero and span readings for HC, CO, NO, and 

CO2 have stabilized, within the accuracy values specified in §85.3(c)(3) for 

five minutes without adjustment. 

Page 24	 7/2/96 Test Equipment Specifications 
§85.3	 §85.3 

(vi)	 Zero Drift Lockout. If zero or span drift cause the optical bench signal levels 

to move beyond the adjustment range of the analyzer, the system shall be 

locked out from testing. 

(vii)	 Electromagnetic Isolation and Interference. Electromagnetic signals found in 

an automotive service environment shall not cause malfunctions or changes 

in the accuracy in the electronics of the analyzer system. The instrument 

design shall ensure that readings do not vary as a result of electromagnetic 

radiation and induction devices normally found in the automotive service 

environment, including high energy vehicle ignition systems, radio frequency 

transmission radiation sources, and building electrical systems. 

(viii)	 Vibration and Shock Protection. System operation shall be unaffected by the 

vibration and shock encountered under the normal operating conditions 

encountered in an automotive service environment. 

(ix)	 Propane Equivalency Factor. The nominal PEF range shall be between 0.490 

and 0.540. For each audit/calibration point, the nominal PEF shall be 

conveniently displayed for the quality assurance inspector and other 

authorized personnel. If an optical bench must be replaced in the field, any 

external labels shall be changed to correspond to the nominal PEF of the new 

bench. The analyzer shall incorporate an algorithm relating PEF to HC 

concentration. Corrections shall be made automatically. The corrected PEF 

value may cover the range of 0.470 to 0.560. 

(x)	 System Response Requirements. The response time from the probe to the 

display for HC, CO, and CO2 analyzers shall not exceed 8 seconds for 90% 

of a step change in input, nor shall it exceed 12 seconds to 95% of a step 

change in input. The response time for a step change in O2 from 20.9% O2 

to 0.1% O2 shall be no longer than 40 seconds. For NO analyzers, the 

response time shall not exceed 12 seconds for 90% of a step change in input. 

The response time for a step change in NO from a stabilized reading to 10% 

of that reading shall be no longer than 12 seconds. 

(3)	 Detection Methods, Instrument Ranges, Accuracy, and Repeatability. 

(i)	 Hydrocarbon Analysis. Hydrocarbon analysis shall be determined by nondispersive infrared (NDIR) analyzer. The analyzer shall cover at least the 

range of 0 ppm HC to 9999 ppm HC, where ppm HC is parts per million of 

hydrocarbon volume as hexane. The accuracy of the instrument from 0-2000 

ppm HC shall be ±3% of point or 4 ppm C6, whichever is greater. The 

accuracy of the instrument between 2001 ppm HC and 5000 ppm HC shall be 

at least ±5% of point. The accuracy of the instrument between 5001 ppm HC 

and 9999 ppm HC shall be at least ±10% of point. The instrument shall 

comply with the quality control specifications in §85.4(d). 

(ii)	 Carbon Monoxide Analysis. Carbon monoxide analysis shall be determined 

by non-dispersive infrared (NDIR) analyzer. The analyzer shall cover at least 

Page 25	 7/2/96 Test Equipment Specifications 
§85.3 §85.3 

(iii) 

(iv) 

(v) 

(vi) 

(vii) 

the range of 0.00 % CO to 14.00% CO, where % CO is % volume CO. The 

accuracy of the instrument between 0.01% and 10.00% CO shall be ±3% of 

point or 0.02% CO, whichever is greater. The accuracy of the instrument 

between 10.01% and 14.00% shall be at least ±5% of point. The instrument 

shall comply with the quality control specifications in §85.4(d). 

Carbon Dioxide Analysis. Carbon dioxide analysis shall be determined by 

non-dispersive infrared (NDIR) analyzer. The analyzer shall cover at least 

the range of 0.0 % CO2 to 18.0% CO2. The accuracy of the instrument 

between 0.01% and 16.00% CO2 shall be ±3% of point or 0.3% CO2, 

whichever is greater. The accuracy of the instrument between 16.01% and 

18.00% shall be at least ±5% of point. The instrument shall comply with the 

quality control specifications in §85.4(d). 

Nitric Oxide Analysis. The analyzer shall cover at least the range of 0 ppm 

NO to 5000 ppm NO, where ppm NO is parts per million nitric oxide. The 

accuracy of the instrument between 0 and 4000 ppm shall be at least ±4% of 

point or 25 ppm NO, whichever is greater. The accuracy of the instrument 

between 4001 and 5000 ppm shall be at least ±8% of point. The instrument 

shall comply with the quality control specifications in §85.4(d). 

Oxygen Analysis. (optional) If an oxygen analyzer is included, the analyzer 

shall cover at least the range of 0.0% O2 to 25.0% O2. The accuracy of the 

instrument over this range shall be at least 5% of point or ±0.1% O2, 

whichever is greater. The instrument shall comply with the quality control 

specifications in §85.4(d). 

Repeatability. The repeatability for the HC analyzer in the range of 0-1400 

ppm HC shall be 2% of point or 3 ppm HC absolute, whichever is greater. In 

the range of 1400-2000 ppm HC, the repeatability shall be 3% of point. The 

repeatability for the CO analyzer in the range of 0-7.00% CO shall be 2% of 

point or 0.02% CO absolute, whichever is greater. In the range of 7.00% to 

10.00% CO, the repeatability shall be 3% of point. The repeatability for the 

CO2 analyzer in the range of 0-10.0% CO2 shall be 2% of point or 0.1% CO2 

absolute, whichever is greater. In the range of 10.0% to 16.0% CO2, the 

repeatability shall be 3% of point. The repeatability of the NO analyzer shall 

be 3% of point or 20 ppm NO, whichever is greater. The repeatability of the 

O2 analyzer shall be 3% of point or 0.1% O2, whichever is greater. 

Rounding Rule. Rounding beyond the decimal places shown in §85.3(c)(3) 

shall follow the standard mathematical practice of going to the next higher 

number for any numerical value of five or more. This shall also hold true for 

pass/fail decisions. For example, if 2.00% CO passes and 2.01% CO fails, 

and the reading is 2.0049%, the value shall be rounded down and the decision 

shall be a pass. If the reading is 2.0050, the value shall be rounded up and 

the decision shall be a fail. The value displayed and printed on the test report 

shall be consistent with the value used for the pass/fail decision. 

Page 26 7/2/96 Test Equipment Specifications 
§85.3	 §85.3 

(4)	 Ambient Conditions. The current relative humidity, dry-bulb temperature, and 

barometric pressure shall be measured and recorded prior to the start of every 

inspection in order to calculate Kh (nitric oxide correction factor §85.1(b)(1)(v)). 

(i)	 Relative Humidity. The relative humidity measurement device shall cover 

the range from 5% to 95% RH, between 35_F - 110_F, with a minimum 

accuracy of ±3% RH. Wet bulb thermometers shall not be used. 

(ii)	 Dry-bulb Temperature. The dry-bulb temperature device shall cover the 

range from 0_F - 140_F with a minimum accuracy of 3_F. 

(iii)	 Barometric Pressure. The barometric pressure measurement device shall 

cover the range from 610 mm Hg - 810 mm Hg absolute (24-32 inches), and 

35_F - 110_F, with a minimum accuracy of ±3% of point or better. 

(5)	 Engine Speed Detection. The analyzer shall utilize a tachometer capable of 

detecting engine speed in revolutions per minute (rpm) with a 0.5 second response 

time and an accuracy of ±3% of the true rpm. Starting in 1998, on vehicles equipped 

with onboard diagnostic (OBD) systems, the engine speed shall be taken by 

connecting to the SAE standardized OBD link on 1996 and newer vehicles. RPM 

readings shall be recorded on a second-by-second basis for the 10 second period 

upon which the pass/fail basis is based. 

(6)	 OBD Fault Code Retrieval. Starting in 1998, the system shall include the hardware 

and software necessary to access the onboard computer systems on 1996 and newer 

vehicles, determine OBD readiness, and recover stored fault codes using the SAE 

standardized link. 

(d)	 Automated Test Process Software and Displays. 

(1)	 Software. The testing process, data collection, and quality control features of the 

analyzer system shall be automated to the greatest degree possible. The software 

shall automatically select the emission standards and set the vehicle load based on an 

EPA-provided or approved look-up table. Vehicle identification information shall be 

derived from a database accessed over a real-time data system to a host computer 

system. Entry of license plate and all or part of the VIN shall be sufficient to access 

the vehicle record. Provision shall be made for manual entry of data for vehicles not 

in the host computer system. 

(2)	 Test and mode timers. The analyzer shall be capable of simultaneously determining 

the amount of time elapsed in a test (overall test time), and in a mode within that test 

(mode time). 

(3)	 Clocks and Timers. The clock used to check the coast-down time shall be accurate 

to within 0.1% of reading between 0.5 and 100 seconds, with a resolution of 0.001 

seconds. The test mode timers used shall be accurate to within 0.1% of reading 

between 10 and 1000 seconds with a resolution of 0.1 seconds. 

Page 27	 7/2/96 Test Equipment Specifications 
§85.3	 §85.3 

(4)	 Driver's Aid. The system shall be equipped with a driver's aid that shall be clearly 

visible to the driver as the test is performed. The aid shall continuously display the 

required speed, the number of seconds into the test mode, the driver's actual 

speed/time performance (a display showing the deviation between set-point and 

actual driving trace), engine RPM, the use of augmented braking, and necessary 

prompts and alerts. The driver's aid shall also be capable of displaying test and 

equipment status and other messages as required. Dynamic information being 

displayed shall be refreshed at a minimum rate of twice per second. Emissions 

values shall not be displayed during official testing. 

(5) Minimum Analyzer Display Resolution. The analyzer electronics shall have 

sufficient resolution to achieve the following: 

HC 1 ppm HC as hexane 

NO 1 ppm NO 

CO 0.01 % CO 

CO2 0.1 % CO2 

O2 0.1 % O2 (optional) 

RPM 10 RPM 

Speed 0.1 mph 

Load 0.1 hp 

Relative Humidity 1 % RH 

Dry Bulb Temperature 1 _F
 

Barometric Pressure 1 mm HG
 

Page 28	 7/2/96 Test Equipment Specifications 
§85.4	 §85.4 

§85.4 Quality Control Requirements 

(a)	 General Requirements 

(1)	 Minimums. The frequency and standards for quality control specified here are 

minimum requirements, unless modified as specified in §85.4(a)(2). Greater 

frequency or tighter standards may be used as needed. 

(2)	 Statistical Process Control. Reducing the frequency of the quality control checks, 

modifying the procedure or specification, or eliminating the quality control checks 

altogether may be allowed if the state demonstrates and the Administrator 

determines, for the purpose of properly conducting an approved short test, that 

sufficient Statistical Process Control (SPC) data exist to make a determination, that 

the SPC data support such action, and that taking such action will not significantly 

reduce the quality of the emissions measurements. Should emission measurement 

performance or quality deteriorate as a result of allowing such actions, the approval 

shall be suspended and the frequencies, procedures specifications, or checks 

specified here or otherwise approved shall be reinstated, pending further 

determination by the Administrator. 

(b)	 Dynamometer 

(1)	 Coast Down Check. 

(i)	 The calibration of each dynamometer shall be automatically checked every 

72 hours in low volume stations (less than 4000 tests per year) and daily in 

high volume stations by a dynamometer coast-down procedure equivalent to 

§86.118-78 (for reference see National Vehicle and Fuel Emission 

Laboratory's Testing Services Division test procedure TP-302A and TP-202) 

between the speeds of 30-20 mph if the ASM2525 is used and 20-10 mph if 

the ASM5015 is used. All rotating dynamometer components shall be 

included in the coast-down check. Speed windows smaller than ± 5 mph may 

be used provided that they show the same calibration capabilities. 

(ii)	 The base dynamometer inertia (2000 pounds) shall be checked at two 

random horsepower settings for each speed range. The two random 

horsepower settings shall be between 8.0 and 18.0 horsepower. A shunt 

resistor for a load cell performance check shall not be used. 

(iii)	 The coast-down procedure shall use a vehicle off-dynamometer type method 

or equivalent. Using a vehicle to bring the dynamometer up to speed and 

removing the vehicle before the coast-down shall not be permitted. If either 

the measured 30-20 mph coast-down time or 20-10 mph coast-down time is 

outside the window bounded by the Calculated Coast-Down Time (CCDT) 

(seconds) ±7% then it shall be locked out for official testing purposes until 

recalibration allows a passing value. 

(A)	 Randomly select an IHP2525 value that is between 8.0 hp and 18.0 hp 

and set dynamometer PAU to this value. 

Page 29	 7/2/96 Quality Control Requirements 
 

 

§85.4	 §85.4 

Coast-down dynamometer from 30-20 mph. 

(

Ł
 

0.5 * DIW
 

32.2

)

ł
 

 * (V30

2 - V202)

CCDT @ 25 mph = 550 * (IHP2525 + PLHP25)
 

Where: 

DIW = Dynamometer Inertia Weight. Total "inertia" 

weight of all rotating components in dynamometer. 

V = Velocity in feet/sec at 30 mph. 30
 

V Velocity in feet/sec at 20 mph. 20 = 

IHP2525 = Randomly selected ASM2525 indicated 

horsepower. 

PLHP25 = Parasitic Horsepower for specific dynamometer at 

25 mph. 

(B)	 Randomly select an IHP5015 value that is between 8.0 hp and 18.0 hp 

and set dynamometer PAU to this value. 

Coast-down dynamometer from 20-10 mph. 

(

Ł
 

0.5 * DIW
 

32.2

)

ł
 

 * (V20

2 - V102)

CCDT @ 15 mph = 550 * (IHP5015 + PLHP15)
 

Where: 

DIW =	 Dynamometer Inertia Weight. Total "inertia" 

weight of all rotating components in dynamometer. 

V = Velocity in feet/sec at 20 mph. 20 

V = Velocity in feet/sec at 10 mph. 10 

IHP5015 =	 Randomly selected ASM5015 indicated 

horsepower. 

PLHP15 =	 Parasitic Horsepower for specific dynamometer at 

15 mph. 

(2)	 Parasitic Value Calculations. 

(i)	 Parasitic losses shall be calculated using the following equations at 25 and 15 

mph whenever a coast-down check is performed. The indicated horsepower 

(IHP) shall be set to zero for these tests. This is only necessary if the coastdown values do not verify in §85.4(b)(1)(iii) above. 

Page 30	 7/2/96 Quality Control Requirements 
 

 

§85.4	 §85.4 

(ii)	 Parasitic losses at 25 mph for a dynamometer with specified diameter rollers. 

(

Ł
 

0.5 * DIW
 

32.2

)

ł
 

 * (V30

2 - V202)

PLHP25 =
 550 * (ACDT)
 

Where: 

DIW = Dynamometer Inertia Weight. Total "inertia" 

weight of all rotating components in dynamometer. 

V = Velocity in feet/sec at 30 mph. 30 

V = Velocity in feet/sec at 20 mph. 20 

ACDT =	 Actual coast-down time required for dynamometer to 

coast from 30 to 20 mph. 

(iii)	 Parasitic losses at 15 mph for a dynamometer with specified diameter rollers. 

(

Ł
 

0.5 * DIW
 

32.2

)

ł
 

 * (V20

2 - V102)

PLHP15 =
 550 * (ACDT)
 

Where: 

DIW = Dynamometer Inertia Weight. Total "inertia" 

weight of all rotating components in dynamometer. 

V = Velocity in feet/sec at 20 mph. 20 

V = Velocity in feet/sec at 10 mph. 10 

ACDT =	 Actual coast-down time required for dynamometer to 

coast from 20 to 10 mph. 

(3)	 Roll Speed. Roll speed and roll counts shall be checked at least once per week by an 

independent means (e.g., photo tachometer). Deviations greater than ±0.2 mph or a 

comparable tolerance in roll counts shall require corrective action. Alternatively, a 

redundant roll speed transducer independent of the primary transducer may be used 

in lieu of the weekly comparison. Accuracy of redundant systems shall be checked 

bimonthly. 

(4)	 Load Measuring Device. If the dynamometer fails a coast-down check or requires a 

recalibration for any other reason, the load measuring device shall be checked using 

a dead-weight method or an equivalent procedure proposed by the state and 

approved by the Administrator. The check shall cover at least three points over the 

range of loads used for vehicle testing. Dead weights shall be traceable to the 

National Institute of Standards (NIST) and shall be accurate to within ±0.1%. The 

dynamometer shall provide an automatic load measuring device calibration and 

verification feature. 

(5)	 Acceptance Check. 

Page 31	 7/2/96 Quality Control Requirements 
 

§85.4	 §85.4 

(i)	 Load Cell Verification (if equipped). This test confirms the proper operation 

of the dynamometer load cell and associated systems. Weights in the proper 

range shall be supplied by the system supplier. Weights shall be NIST 

traceable to 0.1% of point. 

(A)	 Calibrate the load cell according to the manufacturer's direction. 

(B)	 Using a dead weight method, load the test cell to 20%, 40%, 60%, and 

80% (in ascending order) of the range used for ASM testing. Record 

the readings for each weight. Remove the weights in the same steps 

(descending order) and record the results. 

(C)	 Perform steps A through B two more times (total of three). Calculate 

the average value for each weight. Multiply each average weight from 

E by the length of the torque arm. 

(D)	 Acceptance Criteria: The difference for each reading from the weight 

shall not exceed 1% of full scale. 

(ii)	 Speedometer Verification. This test confirms the accuracy of the 

dynamometer's speedometer. 

(A)	 Set dynamometer speed to 15 mph. Independently measure and record 

dynamometer speed. Repeat at 25 mph. 

(B)	 Acceptance Criteria: The difference for each reading from set 

dynamometer speed shall not exceed 0.2 mph. 

(iii)	 Parasitics Verification. Parasitic losses shall be calculated using the 

following equations at 25 and 15 mph . The indicated horsepower (IHP) 

shall be set to zero for these tests. Using time versus speed data from the 

system, calculate PLHP for 25 mph and 15 mph. 

(A)	 Parasitic losses at 25 mph for a dynamometer with specified diameter 

rollers. 

(

Ł
 

0.5 * DIW
 

32.2

)

ł
 

 * (V30

2 - V20

2)

PLHP25 =
 550 * (CDT)
 

Where: 

DIW = Dynamometer Inertia Weight. Total "inertia" 

weight of all rotating components in dynamometer. 

V30 = Velocity in feet/sec at 30 mph. 

V20 = Velocity in feet/sec at 20 mph. 

CDT = Coast-down time required for dynamometer to coast 

from 30 to 20 mph. 

Page 32	 7/2/96 Quality Control Requirements 
 

 

§85.4	 §85.4 

(B)	 Parasitic losses at 15 mph for a dynamometer with specified diameter 

rollers. 

(

Ł
 

0.5 * DIW
 

32.2

)

ł
 

 * (V20

2 - V102)

PLHP15 =
 550 * (CDT)
 

Where: 

DIW = Dynamometer Inertia Weight. Total "inertia" 

weight of all rotating components in dynamometer. 

V = Velocity in feet/sec at 20 mph. 20 

V = Velocity in feet/sec at 10 mph. 10 

CDT =	 Coast-down time required for dynamometer to coast 

from 20 to 10 mph. 

(C)	 Acceptance Criteria: The difference between the externally calculated 

value and the machine calculated value shall not exceed 0.25 HP. 

(iv)	 Verify Coast-Down. The coast-down procedure shall use a vehicle offdynamometer type method or equivalent. Using a vehicle to bring the 

dynamometer up to speed and removing the vehicle before the coast-down 

shall not be permitted. 

(A)	 Randomly select an IHP2525 value that is between 8.0 hp and 18.0 hp 

and set dynamometer PAU to this value. 

Coast-down dynamometer from 30-20 mph. 

CCDT@25 mph = 

(

Ł
 

0.5 * DIW
 

32.2

)

ł
 

 * (V30

2 - V20

2)

 550 * (IHP2525yy + PLHP25-yy) 

Where: 

DIW = Dynamometer Inertia Weight. Total "inertia" 

weight of all rotating components in dynamometer. 

V = Velocity in feet/sec at 30 mph. 30
 

V Velocity in feet/sec at 20 mph. 20	 = 

IHP2525 =	 Randomly selected ASM2525 indicated 

horsepower. 

PLHP25 =	 Parasitic Horsepower for specific dynamometer at 

25 mph. 

(B)	 Randomly select an IHP5015 value that is between 8.0 hp and 18.0 hp 

and set dynamometer PAU to this value. 

Page 33	 7/2/96 Quality Control Requirements 
 

§85.4	 §85.4 

Coast-down dynamometer from 20-10 mph. 

(

Ł
 

0.5 * DIW
 

32.2

)

ł
 

 * (V20

2 - V102)

CCDT@15 mph = 550 * (IHP5015yy + PLHP15-yy) 

Where: 

DIW = Dynamometer Inertia Weight. Total "inertia" 

weight of all rotating components in dynamometer. 

V = Velocity in feet/sec at 20 mph. 20 

V = Velocity in feet/sec at 10 mph. 10 

IHP5015 =	 Randomly selected ASM5015 indicated 

horsepower. 

PLHP15 =	 Parasitic Horsepower for specific dynamometer at 

15 mph. 

(C)	 Acceptance Criteria: The measured 30-20 mph coast-down time and 

the 20-10 mph coast-down time must be inside the window bounded by 

CCDT (seconds) ± 7%. 

(c)	 Emission Sampling System. 

(1)	 Leak Check. The entire sample system shall be checked for vacuum leaks on a daily 

basis and proper flow on a continuous basis. This may be accomplished using a 

vacuum decay method, reading a span gas, or other methods proposed by a state and 

approved by the Administrator. The analyzer shall not allow an error of more than 

1% of reading using the high-range span gas described in §85.4(d)(2)(iii)(C). The 

analyzer shall be locked out from testing if the leak check is not performed when due 

or fails to pass the check. 

(2)	 Dilution. The flow rate on the analyzer shall not cause more than 10% dilution 

during sampling of exhaust of a 1.6 liter engine a normal idle. Ten percent dilution 

is defined as a sample of 90% exhaust and 10% ambient air. 

(3)	 Dilution Acceptance Test. 

(i)	 Set vehicle with 1.6 liter maximum engine displacement at factory ­

recommended idle speed, OEM configuration exhaust system, transmission in 

neutral, hood up (a fan to cool the engine may be used if needed). Set idle 

speed not to exceed 920 RPM. (Set for 900 RPM with a tolerance ± 20 

RPM.) 

(ii)	 With a laboratory grade analyzer system, sample the exhaust at 40 

centimeters depth with a flow sample rate below 320 liters per hour. Allow 

sufficient time for this test. Record all HC, CO, NO, CO2, and O2 readings. 

Page 34	 7/2/96 Quality Control Requirements 
§85.4	 §85.4 

A chart recorder or electronically stored data may be used to detect the point 

of stable readings. 

(iii)	 While operating the candidate analyzer system in a mode which has the same 

flow rate as the official test mode, record the levels of HC, CO, NO, CO2, 

and O2. Ensure that the probe is installed correctly. 

(iv)	 Repeat step (ii). 

(v)	 Acceptance Criteria: If the difference of the readings between (ii) and (iv) 

exceed five percent of the average of (ii) and (iv), repeat (ii), (iii), and (iv); 

otherwise average (ii) and (iv) and compare with (iii). If (iii) is within 10 

percent of the average of (ii) and (iv), then the equipment meets the dilution 

specification. 

(d)	 Analytic Instruments. 

(1)	 General Requirements. The analyzer shall, to the extent possible, maintain accuracy 

between gas calibrations taking into account all errors, including noise, repeatability, 

drift, linearity, temperature, and barometric pressure. 

(2)	 Two-Point Gas Calibration and Low-Range Audit . 

(i)	 Analyzers shall automatically require a zero gas calibration and a high-range 

gas calibration for HC, CO, NO, and CO2. The system shall also use a lowrange gas to check the calibration in the range of vehicle emission standards. 

In high volume stations (4000 or more tests per year), analyzers shall be 

calibrated within four hours before each test. In low volume stations (below 

4000 tests per year), analyzers shall be calibrated within 72 hours before each 

test. If the system does not calibrate or is not calibrated, the analyzer shall 

lock out from testing until corrective action is taken. 

(ii)	 Gas Calibration and Check Procedure. Gas calibration shall be accomplished 

by introducing span gases that meet the requirements of 85.4(d)(2)(iii) into 

the calibration port. The pressure in the sample cell shall be the same with 

the calibration gas flowing as with the sample flowing during testing. The 

analyzer channels shall be adjusted to the center of the allowable tolerance 

range as a result of the calibration. The system shall record the gas reading 

data from before the adjustment and other data pertinent to control charting 

analyzer performance. 

(A)	 Zero the analyzer and perform a leak check. 

(B)	 Calibrate the analyzer using the high-range calibration gas specified in 

§85.4(d)(2)(iii). 

(C)	 Introduce the low-range check gas specified in §85.4(d)(2)(iii). If the 

low-range check gas readings differ from the label value by more than 

±2%, the analyzer shall be locked out from testing. 

Page 35	 7/2/96 Quality Control Requirements 
§85.4	 §85.4 

(iii)	 The following gases shall be used for the 2-point calibration and low-range 

audit. 

(A)	 Zero Gas
 

O2 = 20.7%
 

HC < 1 ppm THC
 

CO < 1 ppm
 

CO2 < 400 ppm
 

NO < 1 ppm 

N2 = Balance 99.99 % pure 

(B)	 Low-Range Audit Gas
 

HC = 200 ppm propane
 

CO = 0.5 %
 

CO2 = 6.0 %
 

NO = 300 ppm 

N2 = Balance 99.99 % pure 

(C)	 High-Range Calibration Gas
 

HC = 3200 ppm propane
 

CO = 8.0 %
 

CO2 = 12.0 %
 

NO = 3000 ppm 

N2 = Balance 99.99 % pure 

(iv)	 Traceability. The audit and span gases used for the gas calibration shall be 

traceable to National Institute of Standards and Technology (NIST) standards 

±1%. Gases shall have a zero blend tolerance. Stations that use large 

capacity gas bottles (size B or larger) and that provide a quality control check 

to insure proper entry of gas values, may use gases with a blend tolerance of 

up to 5%. Gases with a 5% blend tolerance may also be used by any station 

if the analyzer system reads the bar-coded calibration gas bottle specifications 

and adjusts the calibration accordingly. 

(3)	 Five-Point Calibration Audit. 

(i) Analyzers shall automatically require and successfully pass a five point gas 

audit for HC, CO, NO, and CO2. For high volume stations, audits shall be 

checked monthly. In low volume stations, analyzers shall undergo the audit 

procedure every six months. 

(ii)	 Gas Audit Procedure. Calibration auditing shall be accomplished by 

introducing audit gas through the probe. The pressure in the sample cell shall 

be the same with the audit gas flowing as with the sample flowing during 

testing. 

(A)	 Zero the analyzer and perform a leak check. 

Page 36	 7/2/96 Quality Control Requirements 
§85.4	 §85.4 

(B)	 Flow the low range audit gas specified in §85.4(d)(3)(iii) through the 

sample probe, ensuring that the tip is equal to ambient barometric 

pressure ±0.1 inches Hg (a balloon teed into the gas flow line is an 

acceptable pressure indicator; the balloon should stand slightly erect). 

(C)	 When the HC, CO, NO, and CO2 readings have stabilized (no less than 

20 seconds of gas flow) record them as well as the PEF value at each 

audit blend. 

(D)	 Repeat steps B and C for each audit gas specified in §85.4(d)(3)(iii). 

(E)	 Compare the readings with the audit gas values. Divide the HC reading 

by its PEF using the following relationship: 

(Reading - Cylinder Value) Tolerance % = 100 * Cylinder Value 

(F)	 If the tolerance exceeds ±4.0% for CO, CO2, and HC/PEF, or ±5.0% for 

NO, then the analyzer shall fail the gas audit and shall be locked out 

from testing until it passes. 

(iii) The following gases shall be used for the five-point calibration audit. 

(A)	 Zero Audit Gas
 

O2 = 20.7% (if O2 span is desired)
 

HC < 0.1 ppm THC
 

CO < 0.5 ppm
 

CO2 < 1 ppm
 

NO < 0.1 ppm
 

N2 = Balance 99.99 % pure
 

(B)	 Low Range Audit Gas
 

HC = 200 ppm propane
 

CO = 0.5 %
 

CO2 = 6.0 %
 

NO = 300 ppm
 

N2 = Balance 99.99 % pure
 

(C)	 Low-Middle Range Audit Gas
 

HC = 960 ppm propane
 

CO = 2.4 %
 

CO2 = 3.6 %
 

NO = 900 ppm
 

N2 = Balance 99.99 % pure
 

(D)	 High-Middle Range Audit Gas
 

HC = 1920 ppm propane
 

CO = 4.8 %
 

Page 37	 7/2/96 Quality Control Requirements 
 

§85.4	 §85.4 

CO2 = 7.2 % 

NO = 1800 ppm 

N2 = Balance 99.99 % pure 

(E)	 High Range Audit Gas
 

HC = 3200 ppm propane
 

CO = 8.0 %
 

CO2 = 12.0 %
 

NO = 3000 ppm 

N2 = Balance 99.99 % pure 

(iv)	 Traceability. The gases used for the audit shall be traceable to National 

Institute of Standards and Technology (NIST) standards ±1%. Gases shall 

have a zero blend tolerance. 

(4)	 Service, Repair and Modification. 

(i)	 Each time an analyzer's emissions measurement system, sensor, or other 

related electronic components are repaired or replaced, the calibration audit 

required in §85.4(d)(3) shall be performed, at a minimum, prior to returning 

the unit to service. 

(ii)	 Each time the sample line integrity is broken, a leak check shall be performed 

prior to testing. 

(5)	 Acceptance Testing. 

(i)	 Analyzer accuracy. This test confirms the ability of the candidate instruments 

to read various concentrations of gases within the tolerances required by this 

specification. The test compares the response of the candidate instrument 

with that of standard instruments, and also estimates the uncertainty of the 

readings. 

The analyzer shall be zeroed and gas calibrated using the high-range 

calibration gas. The instrument shall be tested using propane, carbon 

monoxide, carbon dioxide, and nitric oxide in nitrogen, with a certified 

accuracy of ±1%, in the following concentrations: 0%, 10%, 20%, 30%, 40%, 

50%, 60%, 70%, 80%, 90% of full scale for the analyzers. Full scale is 

defined in §85.3(c)(3). 

(A)	 Introduce the gases in ascending order of concentrations beginning with 

the zero gas. Record the readings of the standard and candidate 

instruments to each concentration value. 

(B)	 After the highest concentration has been introduced and recorded, 

introduce the same gases to the standard and candidate analyzers in 

descending order, including the zero gas. Record the reading of 

analyzers to each gas, including negatives (if any). 

Page 38	 7/2/96 Quality Control Requirements 
§85.4	 §85.4 

(C)	 Repeat steps A and B for the candidate only, four more times (total of 

five times). 

(D)	 Calculations: 

1.	 Calculate the average value of each concentration for the 

readings of the standard instruments. 

2.	 Calculate the mean and standard deviation of each candidate's 

readings for each concentration. Include both upscale and 

downscale readings for the same gas concentration. (All 

calculations may not be possible for zero concentrations.) 

3.	 For each concentration, calculate the difference between the 

candidate mean and the standard average. 

4.	 For each concentration, compute the following: 

(i)	 Y1 = x + Ksd 

(ii) Y2 = x - Ksd 

Where 

Ksd = std dev * 3.5 for zero and the highest concentration 

value 

Ksd = std dev * 2.5 for all other concentration values 

x = mean (arithmetic average) of the set of candidate readings. 

5.	 Compute the uncertainty (U) of the calibration curve for each 

concentration as follows: 

(i)	 U1 = concentration value - Y1 

(ii)	 U2 = concentration value - Y2 

6.	 Acceptance Criteria: 

(a)	 For each concentration, the differences calculated in Step 3 

shall be no greater than the accuracy tolerances specified in 

§85.3(c)(3) for each instrument. 

(b)	 For each concentration, the uncertainties, (U1 and U2) shall 

be no greater than the accuracy tolerances required in 

§85.3(c)(3). 

(ii)	 Analyzer System Repeatability. This test characterizes the ability of the 

instrument to give consistent readings when repeatedly sampling the same 

gas concentration. 

(A)	 Using an 80% full scale gas, introduce the gas through the calibration 

port. Record the readings. 

Page 39	 7/2/96 Quality Control Requirements 
§85.4 §85.4 

(B) Purge with ambient air for at least 30 seconds but no more than 60 

seconds. 

(C) Repeat steps A and B above four more times. 

(D) Repeat steps A, B, and C, introducing the gas through the sample probe. 

(E) Acceptance Criteria: The differences between the highest and lowest 

readings from both ports shall not exceed the values specified in 

§85.3(c)(3)(vi). 

(iii) Analyzer System Response Time. This test determines the speed of response 

of the candidate instrument when a sample is introduced at the sample probe. 

(A) Gas calibrate the candidate instrument per the manufacturer's 

instructions. 

(B) Using a solenoid valve or equivalent selector system, remotely 

introduce an 80% full scale gas to the probe. The gas pressure at the 

entrance to the probe shall be equal to room ambient. 

(C) Measure the elapsed time required for the instrument display to read 

90% and 95% of the final stabilized reading for HC, CO, CO2 and NO. 

(Optional: Also, measure the time required for the O2 analyzer to read 

0.1% O2). Alternatively the bench outputs may be recorded against a 

time base to determine the response time. Record all times in seconds. 

(D) Switch the solenoid valve to purge with zero air for at least 40 seconds 

but no more than 60 seconds. 

(E) Measure the elapsed time required for the NO instrument display to read 

10% of the stabilized reading in Step C. 

(F) Repeat steps A, B, and C, two more times (total three times). 

(G) Acceptance Criteria: The response (drop time for O2 and NO; rise time 

for HC, CO, CO2 and NO) times shall meet the requirement specified in 

§85.3(c)(2)(x). The response time shall also be within ±1 second of the 

nominal response time supplied by the equipment supplier for use in 

§85.5(b)(5). 

(iv) Analyzer Interference Effects. The following acceptance test procedure shall 

be performed at 45_F, 75_F, and 105_F conditions, except as noted. 

(A) Zero and span the instrument. 

(B) Sample the following gases for at least one minute. Record the 

response of each channel to the presence of these gases. 

Page 40 7/2/96 Quality Control Requirements 
§85.4	 §85.4 

1. 16% Carbon Dioxide in Nitrogen. 

2. 1600 ppm Hexane in Nitrogen. 

3. 10% Carbon Monoxide in Nitrogen. 

4. 3000 ppm Nitric Oxide in Nitrogen. 

5. 75 ppm Sulfur Dioxide (SO2) in Nitrogen. 

6. 75 ppm Hydrogen Sulfide (H2S) in Nitrogen. 

(C)	 Water-Saturated Hot Air. Water-saturated hot air shall be drawn 

through the probe from the top of a sealed vessel partially filled with 

water through which ambient air will be bubbled. The water shall be 

maintained at a temperature of 122_F ± 9_F. This test shall be 

performed at only the 75_F, and 105_F conditions. 

(D)	 Acceptance Criteria: The interference effects shall not exceed the limits 

specified in §85.3(c)(2)(iii). 

(v)	 Electromagnetic Isolation and Interference. This test shall measure the ability 

of the candidate instrument to withstand electromagnetic fields which could 

exist in vehicle testing and repair facilities. For all tests described below, 

sample "Low-Middle Range Audit Gas" specified in §85.4(d)(3)(iii)(C), at 

atmospheric pressure, through the sample probe. Record analyzer reading 

during test periods. 

(A)	 Radio Frequency Interference Test. 

1.	 Use a test vehicle with an engine having a high energy ignition 

system (or equivalent), a solid core coil wire and a 3/8" air gap. 

Leave engine off. 

2.	 Locate the candidate instrument within 5 feet of the ignition coil. 

Gas calibrate the candidate instrument. 

3.	 Sample gas specified above. Wait 20 seconds, and record 

analyzer readings. 

4.	 Start engine. With the hood open and gas flowing to the 

analyzer, cycle the engine from idle through 25 mph on the 

dynamometer at ASM loads and record the analyzer readings. 

5.	 Relocate the instrument to within 6 inches of one side of the 

vehicle near the engine compartment. Follow procedure 

described in step 4 and record analyzer readings. 

6.	 Relocate the instrument to within 6 inches of the other side of the 

vehicle near the engine compartment. Follow procedure 

described in step 4 and record analyzer readings. 

Page 41	 7/2/96 Quality Control Requirements 
§85.4	 §85.4 

7.	 Acceptance Criteria: The analyzer readings shall deviate no 

more than 0.5% full scale. 

(B)	 Induction Field Test. Use a variable speed (commutator type) hand drill 

having a plastic housing and rated at 3 amps or more. While the 

analyzer is sampling the gas, vary the drill speed from zero to maximum 

while moving from the front to the sides of the instrument at various 

heights. 

Acceptance Criteria: The analyzer readings shall deviate no more than 

0.5% full scale. 

(C)	 Line Interference Test. Plug the drill used in part B above into one 

outlet of a #16-3 wire extension cord approximately 20 feet long. 

Connect the instrument into the other outlet of the extension cord. 

Repeat part B above. 

Acceptance Criteria: The analyzer readings shall deviate no more than 

0.5% full scale. 

(D)	 VHF Band Frequency Interference Test. Locate both a citizens ban 

radio (CB), with output equivalent to FCC legal maximum, and a 

highway patrol transmitter (or equivalent) within 50 feet of the 

instrument. While the analyzer is sampling the gas, press and release 

transmit button of the both radios several times. 

Acceptance Criteria: The analyzer readings shall deviate no more than 

0.5% full scale. 

(E)	 Ambient Conditions Instruments. Upon installation and every six 

months thereafter, the performance of the ambient conditions 

instruments shall be cross checked against a master weather station. 

Acceptance Criteria: The individual instruments shall be within the 

tolerance specified in §85.3(c)(4). 

Page 42	 7/2/96 Quality Control Requirements 
§85.5 §85.5 

§85.5 Test Record Information 

The following information shall be collected for each test performed (both passing and 

failing tests), recorded in electronic form, and made available to EPA upon request. 

(a) General Information. 

(1) 

(2) 

(3) 

(4) 

(5) 

(6) 

(7) 

(8) 

(9) 

(10) 

(11) 

(12) 

(13) 

(14) 

Test Record Number 

Inspection station and inspector numbers 

Test system number 

Dynamometer site 

Date of test 

Emission test start time and the time final emission scores are determined. 

Vehicle identification number 

License plate number 

Test certificate number 

Vehicle model year, make, and type 

Number of cylinders or engine displacement 

Transmission type 

Odometer reading 

Type of test performed (i.e., initial test, first retest, or subsequent retest) 

(b) Ambient Test Conditions. 

(1) 

(2) 

(3) 

(4) 

(5) 

Relative humidity (%) 

Dry-bulb temperature (_F). 

Atmospheric pressure (mm Hg) 

NO correction factor 

Nominal response time for each instrument (Transport + T90) 

(c) ASM Mode or Modes. The following information shall be captured separately for each test 

mode (ASM5015 and/or ASM2525) performed. 

(1) 

(2) 

(3) 

(4) 

(5) 

(6) 

Final HC running average (AvgHC) (ppm) 

Final CO running average (AvgCO) (%) 

Final NO running average (AvgNO) (ppm) 

Total horsepower used to set the dynamometer (THP5015) (hp) 

Engine RPM running average corresponding to the final test score 

Dilution correction factor (DCF) 

(d) Diagnostic/Quality Assurance Information. 

(1) 

(2) 

(3) 

(4) 

(5) 

(6) 

(7) 

(8) 

Test time (seconds) 

Mode time (seconds) 

Vehicle speed (mph) for each second of the test 

Engine RPM for each second of the test 

Dynamometer load (pounds) for each second of the test 

HC concentration (ppm) for each second of the test, not corrected for dilution 

CO concentration (%) for each second of the test, not corrected for dilution 

NO concentration (ppm) corrected for humidity for each second of the test, not 

corrected for dilution 

Page 43 7/2/96 Test Record Information 
§85.5 §85.5 

(9) CO2 concentration (%) for each second of the test 

(10) O2 concentration (%) for each second of the test (optional) 

Page 44 7/2/96 Test Record Information