# Evaluation of Road Grade Profiles for Cruise Cycles with ISX/TC10 Powertrain James Sanchez 8/31/2015

EPA Draft Analysis

# Overview

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1 3 0 5000 10000 15000 20000Road Grade, % 

### Test Cycle Distance, m 

## • In the HD Phase 2 Proposal EPA and NHTSA proposed that the two cruise cycles would also include grade. • While the agencies worked on a nationally representative road grade profile, the agencies used the road grade profile for an actual road in Texas for all the analysis that informed the proposal. • Now that the work has been completed to create nationally representative road grade profiles, the agencies are evaluating the profiles and are seeking feed back from industry on them.

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0 20 40 0 5000 10000 15000 20000Elevation, m 

### Test Cycle Distance, m EPA Draft Analysis

# Development of Nationally Representative, Activity Weighted Road Grade Profiles • N ationally representative, activity weighted road grade profiles for US restricted access highways were developed by the EPA s using the following datasets: • Half hill* and road grade data generated by NREL using a TomTom database (* Continuous stretch of roadway where grade does not change sign ) • Truck activity (VMT) data based on annual reports by individual states and obtained from the 2011 EPA National Emissions Inventory 

### • The following profiles were created to account for truck speed limit effects: • 12 mile (19.3 km) profile representing truck speed limit range of 55 - 75 mph and driven in both directions • 12 mile (19.3 km) profile representing truck speed limit range of 55 - 60 mph a nd driven in both directions • 12 mile (19.3 km) profile representing truck speed limit range of 65 - 75 mph a nd driven in both directions • 2x6 mile (19.3 km) profile representing truck speed limit range of 55 - 75 mph 

### • Each road grade profile consists of half hills representing unique segments of the national half hill population and vehicle activity associated with those segments. The length of each half hill is directly proportional to the VMT it represents. The distribution of road grade within each half hill of a profile is a symmetric representation of the actual, activity weighted distribution of road grade within the corresponding segment of the national half hill population • 2% of the steepest road grades in each half hill road grade distribution were trimmed to the next highest level in order to a voi d the extremes 

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4 9

7,348 9,348 11,348Road Grade, % 

### Test Cycle Distance, m -50 0 50 7,348 9,348 11,348Elevation, m 

### Test Cycle Distance, m EPA Draft Analysis

# New Road Grade Profiles - %Grade

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# New Road Grade Profiles - Elevation
-40 -20 0 20 40 0 5,000 10,000 15,000 20,000Elevation, m 

### Test Cycle Distance, m Profile A (Speed limits 55 - 75 mph) -40 -20 0 20 40 0 5,000 10,000 15,000 20,000Elevation, m 

### Test Cycle Distance, m Profile B (Speed limits 55 - 60 mph)

-20 -10 0 10 20 30 0 5,000 10,000 15,000 20,000Elevation, m 

### Test Cycle Distance, m Profile D (Speed limits 55 - 75 mph) -40 -20 0 20 40 0 5,000 10,000 15,000 20,000Elevation, m 

### Test Cycle Distance, m Profile C (Speed limits 65 - 75 mph) EPA Draft Analysis

# Powertrain Test Configurations

• 2012 Cummins ISX 450 HP • Allison TC10, economy mode • Simulate vehicles • Static Mass: 31,978 kg • Rotating Mass: 1,134 kg • C d

# A : 5.4 • C rr 

# : 6.9 g/kg • Tire Radius: 0.5 m • Axle Eff.: 95.5% • Axle Ratios: 2.4, 2.64, and 3.36 Picture of test setup with Eaton AMT EPA Draft Analysis

# 55 mph Cycles

360 380 400 420 440 460 480

Axle Ratio: 2.4 Axle Ratio: 2.64 Axle Ratio: 3.36Fuel Consumed (g/mile) Proposed A - Fwd A - Rvrs B - Fwd B - Rvrs D 195.000 200.000 205.000 210.000 215.000 220.000 225.000

Axle Ratio: 2.4 Axle Ratio: 2.64 Axle Ratio: 3.36bsfc (g/kw-hr) Proposed A - Fwd A - Rvrs B - Fwd B - Rvrs D 

### • These results plus those on the next slide show that any of these road grades would have noticeable impacts on the numerical values of the standards if one of them is chosen for the final rule, but relative values in % may not be so sensitive. Also, since the baseline (reference case) would also use the new profile, the impact on stringency would be minimized. EPA Draft Analysis

# 65 mph Cycles

195.000 200.000 205.000 210.000 215.000 220.000 225.000 230.000 235.000

Axle Ratio: 2.4 Axle Ratio: 2.64 Axle Ratio: 3.36bsfc (g/kW-hr) Proposed A - Fwd A - Rvrs C - Fwd C - Rvrs D 420 440 460 480 500 520 540 560 580

Axle Ratio: 2.4 Axle Ratio: 2.64 Axle Ratio: 3.36Fuel Consumed (g/mile) Proposed A - Fwd A - Rvrs C - Fwd C - Rvrs D EPA Draft Analysis

# Axle Ratio 2.4, Proposed Profile – 55mph

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# Axle Ratio 2.64, Proposed Profile – 55mph

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# Axle Ratio 3.36, Proposed Profile – 55mph

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# Axle Ratio 2.4, Profile B Forward – 55mph

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# Axle Ratio 2.64, Profile B Forward – 55mph

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# Axle Ratio 3.36, Profile B Forward – 55mph

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# Axle Ratio 2.4, Proposed Profile – 65mph

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# Axle Ratio 2.64, Proposed Profile – 65mph

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# Axle Ratio 3.36, Proposed Profile – 65mph

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# Axle Ratio 2.4, Profile C Forward – 65mph

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# Axle Ratio 2.64, Profile C Forward – 65mph

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# Axle Ratio 3.36, Profile C Forward – 65mph

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# Questions for Industry • Are these grade profiles representative of the cycles used by your company to design/evaluate heavy- duty vehicles? • Does industry have concern with evaluating all vehicles on a nationally representative cycle? • Are vehicle designs tailored to the regional road grades that the vehicle will be used in or are they designed to work across the country? • Does industry believe that there could be unintended consequences for evaluating vehicles on grades above 3% even though they are nationally representative? • The results presented here show that vehicle speed can drop as low as 45mph. Would you expect that many vehicles would drop below 45mph on these road grade profiles? • Do you prefer 55 and 65mph cycles with different road grade profiles, such as Profile B for 55 mph and Profile C for 65mph cycles or just use one road grade profile with both cruise cycles? EPA Draft Analysis

# Other Test Plan on Road Grade Evaluations • Cummins ISB engine and Allison transmission at SwRI • Navistar N13 engine with Eaton transmission at SwRI • Cummins ISX engine and Eaton transmission at ORNL EPA Draft Analysis

# Extra Slides

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# Axle Ratio 2.4, Proposed Profile – 65mph

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# 55 mph Cycles - % Difference from Proposed Cycle

6.7% 8.4% 8.5% 11.0% 7.7% 5.9% 6.8% 7.5% 9.6% 6.0% 5.1% 6.7% 6.3% 8.6% 5.7% A - Fwd A - Rvrs B - Fwd B - Rvrs D 

### Fuel (g/mile) Axle Ratio: 2.4 Axle Ratio: 2.64 Axle Ratio: 3.36 1.2% 1.2% 1.5% 1.0% 1.2% 0.1%

-0.5% 0.5%

- 0.5% -0.4% 0.0%

-0.8% -0.1%

-0.7% -0.3% A - Fwd A - Rvrs B - Fwd B - Rvrs D 

### Fuel (g/kW- hr) Axle Ratio: 2.4 Axle Ratio: 2.64 Axle Ratio: 3.36

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# 6 5 mph Cycles - % Difference from Proposed Cycle

5.8% 7.6% 5.5% 6.2% 6.1% 4.0% 5.5% 3.4% 4.5% 4.6% 3.1% 4.0% 2.8% 3.6% 3.3% A - Fwd A - Rvrs C - Fwd C - Rvrs D 

### Fuel (g/mile) Axle Ratio: 2.4 Axle Ratio: 2.64 Axle Ratio: 3.36 1.3% 1.1% 1.1% 0.9% 0.9% 0.1%

-0.2%
-0.4% - 0.1% -0.2%

-0.9% -0.9% -0.4% -0.2%

-0.9% A - Fwd A - Rvrs C - Fwd C - Rvrs D 

### Fuel (g/kW- hr) Axle Ratio: 2.4 Axle Ratio: 2.64 Axle Ratio: 3.36
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