### 1 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

NATIONAL VEHICLE AND FUEL EMISSIONS LABORATORY

2565 PLYMOUTH ROAD

ANN ARBOR, MICHIGAN 48105

- 2498



### MEMORANDUM

SUBJECT: Draft Baseline GEM Inputs for Tractors, Trailers, and Vocational Vehicles

FROM: Charles Moulis, Senior Environmental Engineer

Assessment and Standards Division

TO: Docket Number EPA

- HQ

- OAR

- 20 14

- 0827

DATE: March 24, 2016

On Marc h 2, 2016 , the agencies issued a Notice of Data Availability (NODA) and placed into the

public docket a revised version of the Greenhouse Gas Emission Model (GEM) that reflects

input received during the public comment period and continued analytical work

. Some

stakeholders have requested additional information to assist in the determination of the baseline

vehicle performance. This memorandum summarizes the draft input values for this revised

version of GEM that reflect the agencies ’ current projection of average values for the model year

2018 baseline heavy

- duty fleet. In other words, running the revised version of GEM using these

inputs will show the average levels of performance the agencies would expect to see from

tractors and vocational vehicles tha t are fully compliant with the 2018 Phase 1 standards. The

input values presented here reflect our projections based on currently available information.

However, we continue to look for new information that would improve our projections. Thus, it

is pos sible that the baseline values that will be used for the final rules will differ from the values

presented here.

Baseline inputs are presented separately here for tractors, trailers and vocational vehicles. The

simpler input values such as tire rolling r esistance and axle ratios are shown in the tables below.

Note that the tables may contain information for more than one regulatory subcategory. More

complex inputs such as axle efficiency maps are attached as data files or were included with the

GEM release

.

The tractor inputs are shown in Table 1

. The tractor table do es not include the aerodynamic

inputs for high roof tractors because the agencies are modifying the aerodynamic test procedures

for high roof tractors in response to the comments received from the Phase 2 Notice of Proposed

Ru lemaking and have not yet completed the analysis of these changes on the inputs. The test

procedure changes are being made to better isolate aerodynamic drag from other road load

components and to reduce variability in test results . Although we cannot pr ovide numerical

values at this time, we can note that isolating the aerodynamic drag would make the new CdA

values lower than the proposed values (see 80 FR 40220). Thus, we expect the baseline

aerodynamic value for high roof sleeper cabs to be less than the proposed 6.22 m 2 

### value. The

2017 MY engine configuration files (including the fuel maps) and a 10 speed manual OFFICE OF

AIR AND RADIATION

### 2

transmission configuration file were included in the release of GEM included in the NODA

. The agencies are posting an updated baseline axl e configuration file for tractors and heavy

heavy

- duty vocational vehicles with this memo.

Table 1 Tractor Inputs

Class 7 Class 8

Day Cab Day Cab Sleeper Cab

Low

Roof Mid

Roof High

Roof Low Roof Mid

Roof High

Roof Low Roof Mid Roof High

Roof

Engine

2017 MY

11L

Engine

350 HP 2017 MY

11L

Engine

350 HP 2017 MY

11L

Engine

350 HP 2017 MY

15L

Engine

455 HP 2017 MY

15L

Engine

455 HP 2017 MY

15L

Engine

455 HP 2017 MY

15L

Engine

455 HP 2017 MY

15L

Engine 455

HP 2017

MY

15L

Engine

455 HP

Aerodynamics (CdA in m 2 )

5.00 6.40 30% Bin

II

60% Bin

III

10% Bin

IV 5.00 6.40 30% Bin

II

60% Bin

III

10% Bin

IV 4.95 6.35 Bin III

Steer Tires (CRR in kg/metric ton)

6.99 6.99 6.87 6.99 6.99 6.87 6.87 6.87 6.54

Drive Tires (CRR in kg/metric ton)

7.38 7.38 7.26 7.38 7.38 7.26 7.26 7.26 6.92

Extended Idle Reduction

– Adjustable AESS with no Idle Red Tech Adoption Rate @ 1% Effectiveness

N/A N/A N/A N/A N/A N/A 87 % 87 % 87 %

Extended Idle Reduction

– Adjustable AESS with Diesel APU Adoption Rate @ 3% Effectiveness

N/A N/A N/A N/A N/A N/A 9 % 9 % 9 %

Transmission = 10 Speed Manual Transmission

Gear Ratios = 12.8, 9.25, 6.76, 4.90, 3.58, 2.61, 1.89, 1.38, 1.00, 0.73

Drive Axle Configuration

= 4x2

Use GEM Default Drive Axle Configuration = 6x4

Use 6x 4 Axle Configuration File Provided with this Memo

Tire Revs/Mile = 512

Drive Axle Ratio = 3.42

### 3

The current default t railer parameters are shown in Table 2. The se values are EPA

- specified

values that remain constant in the GEM simulations. The def ault CdA values are shown as a

range. In response to several commenters , the agencies are considering the use of wind

- averaged

drag results, which will impact the absolute CdA value used in the GEM. Similar to the

proposal, each trailer subcategory has a distinct default CdA value to reflect the aerodynamic

performance of the specific tractor

- trailer combination.

Table 3 shows the GEM inputs used to represent the baseline trailers. We proposed full

- , partial

and non

- aero subcategories for our van trailers and we have created separate baselines for each

of these subcategories. The aerodynamic inputs for the full

- aero long box trailers are based on a

slightly higher adoption of aero devices that perform simi lar ly to skirts, while short box trailers

and those with work

- performing devices that would qualify as partial

- or non

- aero vans are assumed to have no adoption of aerodynamic devices. The baseline t ire rolling resistance

includes higher adoption of S martWay

- verified tires ba sed on information we received in

comments. The baseline weight reduction and tire pressure system adoption are unchanged from

the proposal.

Note that non

- box trailers are not shown in Table 2 or Table 3

, because we proposed to apply

non

- GEM standards to those trailers.

Table 2 Default Trailer Parameters in GEM

Regulatory Subcategory Long Box Van Short B ox Van

Dry Refrigerated Dry Refrigerated

Representative Trailer Length 53

- foot 28

- foot

Standard Tracto r Class 8 high

- roof sleeper cab Class 8 high

- roof day cab

Steady

- State Engine Map 15 L, 455 HP

Total vehicle weight (kg) 31978 33778 15191 16991

De fault CdA Values

- TBD (m2) 5.8

- 6.2

Number of Axles 5 4

Payload (tons) 19 10

CARB HHDDT Drive Cycle Weighting 0.05 0.19

GEM 55 mph Drive Cycle Weighting 0.09 0.17

GEM 65 mph Drive Cycle Weighting 0.86 0.64



### Table 3 Baseline Trailer Inputs

Full

- Aero, Long Box Full

- Aero, Short Box All Partial

- and

Non

- Aero Vans Dry Refrigerated Dry Refrigerated

Delta CdA (m2) 0.2 0.2 0 0 0

CRR (kg/ton) 5.2 5.2 5.2 5.2 6.0

Weight Reduction (lb) 0 0 0 0 0

Tire Pressure System Credit (%) 0.5 0.5 0.3 0.3 0

### 4

Vocational vehicle draft baseline vehicle inputs are shown in Table 4 through Table 11

. The

values not shown in the tables are GEM

- default values unchanged from the proposa l, such as

payload, drag area, and vehicle weight. The agencies are currently considering public comments

received regarding the default drag area for light heavy

- duty vocational vehicles, and although

we expect the final default drag area to be less than the proposed value of 5.4 m 2 

### , we have not

yet completed the analysis necessary to establish a new C d A value for these vehicles.

Table 4 Vocational LH D iesel Inputs

GEM Parameter Regional Multi

- Purpose Urban

CI Engine 2018 MY 7L, 2 00 hp Engine

Transmission Type 6

- speed AT 6

- speed AT 5

- speed AT

Transmission Gears 3.102, 1.8107, 1.4063, 1.0,

0.7117, 0.61 3.102, 1.8107,

1.4063, 1.0,

0.7117

Transmission efficiency

improvement Use GEM Default

Torque converter lockup gear 3 3 3

Axle efficiency improvement Use GEM Default

Drive Axle Gear Ratio 4.1 4.56 4.56

Axle Configuration 4x2 4x2 4x2

Idle Reduction No

Tire Revs/mile 622 622 622

Steer Tires (CRR kg/metric ton) 7.7 7.7 7.7

Drive Tires (CRR kg/metric ton) 7.7 7.7 7.7

Aerodynam ic Improvement 0 0 0

Electrified Accessories 0 0 0

Tire Pressure System 0 0 0

PTO Improvement 0 0 0

Weight Reduction (lb) 0 0 0

### 5 Table 5 Vocational LH Gasoline Inputs

GEM Parameter Regional Multi

- Purpose Urban

S I Engine 2018 MY 6.8 L, 300 hp engine

Transmission Type 6

- speed AT 6

- speed AT 5

- speed AT

Transmission Gears 3.102, 1.8107, 1.4063, 1.0,

0.7117, 0.61 3.102, 1.8107,

1.4063, 1.0,

0.7117

Transmission efficiency

improvement Use GEM Def ault

Torque converter lockup gear 3 3 3

Axle efficiency improvement Use GEM Default

Drive Axle Gear Ratio 4.33 4. 88 4.88

Axle Configuration 4x2 4x2 4x2

Idle Reduction No

Tire Revs/mile 557 557 557

Steer Tires (CRR kg/metric ton) 7.7 7.7 7.7

Drive Tires (CRR kg/metric ton) 7.7 7.7 7.7

Aerodynamic Improvement 0 0 0

Electrified Accessories 0 0 0

Tire Pressure System 0 0 0

PTO Improvement 0 0 0

Weight Reduction (lb) 0 0 0

### 6 Table 6 Vocati onal MH Diesel Inputs

GEM Parameter Regional Multi

- Purpose Urban

CI Engine 2018 MY 7L, 270 hp Engine

Transmission Type 6

- speed AT 6

- speed AT 5

- speed AT

Transmission Gears 3.102, 1.8107, 1.4063, 1.0,

0.7117, 0.61 3.102, 1.8107,

1.4063, 1.0,

0.7117

Trans mission efficiency

improvement Use GEM Default

Torque converter lockup gear 3 3 3

Axle efficiency improvement Use GEM Default

Drive Axle Gear Ratio 4.33 4.88 4.88

Axle Configuration 4x2 4x2 4x2

Idle Reduction No

Tire Revs/mile 517 517 557

Steer Tir es (CRR kg/metric ton) 7.7 7.7 7.7

Drive Tires (CRR kg/metric ton) 7.7 7.7 7.7

Aerodynamic Improvement 0 0 0

Electrified Accessories 0 0 0

Tire Pressure System 0 0 0

PTO Improvement 0 0 0

Weight Reduction (lb) 0 0 0

### 7 Table 7 Vocational MH Gasoline Inputs

GEM Parameter Regional Multi

- Purpose Urban

S I Engine 2018 MY 6.8 L, 300 hp engine

Transmission Type 6

- speed AT 6

- speed AT 5

- speed AT

Transmission Gears 3.102, 1.8107, 1.4063, 1.0,

0.7117 , 0.61 3.102, 1.8107,

1.4063, 1.0,

0.7117

Transmission efficiency

improvement Use GEM Default

Torque converter lockup gear 3 3 3

Axle efficiency improvement Use GEM Default

Drive Axle Gear Ratio 4.33 4. 88 4.88

Axle Configuration 4x2 4x2 4x2

Idle Red uction No

Tire Revs/mile 517 517 517

Steer Tires (CRR kg/metric ton) 7.7 7.7 7.7

Drive Tires (CRR kg/metric ton) 7.7 7.7 7.7

Aerodynamic Improvement 0 0 0

Electrified Accessories 0 0 0

Tire Pressure System 0 0 0

PTO Improvement 0 0 0

Weight Reducti on (lb) 0 0 0

### 8 Table 8 Vocational HH Diesel Inputs

GEM Parameter Regional Multi

- Purpose Urban

CI Engine 2018 MY 15L

455hp Engine 2018 MY 11L, 345 hp Engine

Transmission Type 10

- speed MT 5

- spee d AT

Transmission Gears 12.8, 9.25,

6.76, 4.9,

3.58, 2.61,

1.89, 1.38,

1.0, 0.73 4.6957, 2.213, 1.5291, 1.0,

0.7643

Transmission efficiency

improvement Use GEM Default

Torque converter lockup gear 3 3 3

Axle efficiency improvement Use 6x4 Axle Configur ation File Provided with

this Memo

Drive Axle Gear Ratio 3.76 4.33 5.29

Axle Configuration 6x4 6x4 6x4

Idle Reduction No

Tire Revs/mile 496 496 496

Steer Tires (CRR kg/metric ton) 7.7 7.7 7.7

Drive Tires (CRR kg/metric ton) 7.7 7.7 7.7

Aerodynamic Improvement 0 0 0

Electrified Accessories 0 0 0

Tire Pressure System 0 0 0

PTO Improvement 0 0 0

Weight Reduction (lb) 0 0 0

### 9 Table 9 Vocational HH Gasoline Inputs

GEM Parameter Regional Mu lti

- Purpose Urban

S I Engine 2018 MY 6.8 L, 300 hp engine

Transmission Type 6

- speed AT 6

- speed AT 5

- speed AT

Transmission Gears 4.6957, 2.213, 1.5291, 1.0,

0.7643, 0.6716 4.6957, 2.213,

1.5291, 1.0,

0.7643

Transmission efficiency

improvement Use GEM Defa ult

Torque converter lockup gear 3 3 3

Axle efficiency improvement Use 6x4 Axle Configuration File Provided with

this Memo

Drive Axle Gear Ratio 4.1 4. 33 4.88

Axle Configuration 6x4 6x4 6x4

Idle Reduction No

Tire Revs/mile 496 496 496

Steer Tires ( CRR kg/metric ton) 7.7 7.7 7.7

Drive Tires (CRR kg/metric ton) 7.7 7.7 7.7

Aerodynamic Improvement 0 0 0

Electrified Accessories 0 0 0

Tire Pressure System 0 0 0

PTO Improvement 0 0 0

Weight Reduction (lb) 0 0 0



### Stakeholders interested in simulatin g custom vocational vehicles should enter GEM input s according to the configurations described below in Table 10 and Table 11 . The release of GEM

included in the NODA will give results for the agenci es ’ current estimates of these baseline

vehicles if the simulations are run using the following regulatory subcategory classifications:

Motor homes: MHD_R

School bus: MHD_U

Coach Bus: HHD_R

Transit, Refuse, Mixer, Emergency : HHD_U

### 10 Table 10 Custom Vocational MHD Inputs

GEM Parameter Motor Homes

(Regional) School Bus

(Urban)

CI Engine 2018 MY 7L, 270 hp Engine

Transmission Type 6

- speed AT 5

- speed AT

Transmission Gears 3.102, 1.8 107,

1.4063, 1.0,

0.7117, 0.61 3.102, 1.8107,

1.4063, 1.0, 0.7117

Transmission efficiency

improvement Use GEM Default

Torque converter lockup gear 3 3

Axle efficiency improvement Use GEM Default

Drive Axle Gear Ratio 4.33 4.88

Axle Configuration 4x2 4x2

Idle Reduction No No

Tire Revs/mile 517 517

Steer Tires (CRR kg/metric ton) 7.7 7.7

Drive Tires (CRR kg/metric ton) 7.7 7.7

Aerodynamic Improvement 0 0

Electrified Accessories 0 0

Tire Pressure System 0 0

PTO Improvement 0 0

Weight Reduction ( lb) 0 0

### 11 Table 11 Custom Vocational HHD Inputs

GEM Parameter Coach Bus

(Regional) Transit, Refuse, Mixer,

Emergency (Urban)

CI Engine 2018 MY 11L, 345 hp Engine

Transmission Type 6

- speed AT 5

- speed AT

Transmission Gears 4.6957, 2.213,

1.5291, 1,

0.7643, .6716 4.6957, 2.213, 1.5291,

1, 0.7643

Transmission efficiency

improvement Use GEM Default

Torque converter lockup gear 3 3

Axle efficiency improvement Use 6x4 Axle Configuration File Provi ded

with this Memo

Drive Axle Gear Ratio 4.33 5.29

Axle Configuration 6x4 6x4

Idle Reduction No No

Tire Revs/mile 496 496

Steer Tires (CRR kg/metric ton) 7.7 7.7

Drive Tires (CRR kg/metric ton) 7.7 7.7

Aerodynamic Improvement 0 0

Electrified Acces sories 0 0

Tire Pressure System 0 0

PTO Improvement 0 0

Weight Reduction (lb) 0 0