# Technology Assessment for the Next Phase Heavy

- Duty Greenhouse Gas Emission and Fuel Efficiency Standards

Houshun Zhang, Matt Spears, and Angela Cullen Environmental Protection Agency 

# October 9, 2014SAE INTERNATIONAL 

# Acknowledgement

2 

# • EPA Team

• Byungho Lee, James Sanchez, Prashanth Gururaja, Kevin Newman, Paul Dekraker

• SwRI Team

• Joe Anthony, Jayant Sarlashkar, Anthony Phan, Brian Moczygemba, Charlie RobertsSAE INTERNATIONAL 

# Outline

• GHG Phase II Update

• Technology Assessment in Phase II

• Vehicle Model (GEM) Validations

• Chassis Dyno Test Variability

3SAE INTERNATIONAL 

# Phase 1

- Highlights

 First ever Medium

- & Heavy

- Duty Standards  Will reduce fuel 

# consumption, CO2 emissions, and operating costs for thousands of 

# businesses  Allows manufacturers to produce a single fleet of vehicles to meet requirement  530 million barrels less oil  270 MMT lower GHGs


#  $50 billion in fuel savings
 $49 billion in net benefits

4SAE INTERNATIONAL 

# Phase 1

- Overview

HD Engines Vocational vehicle, regulated via the chassis 5SAE INTERNATIONAL 

# Phase I GEM

Inertial/Braking 0

- 2% Aerodynamic Loss 15

- 22%

Drivetrain 2

- 4% Rolling Resistance 13

- 16% Vehicle Auxiliary Loads

1

- 4% Total Engine Loss 57

- 59%



### EPA pre

- specified
Allowed user inputs • The Greenhouse Gas Emission Model (GEM) is a vehicle simulation tool being used by all vehicle OEMs for demonstrating compliance for the U.S. Greenhouse Gas Emission 

### and Fuel Efficiency Standards

• GEM is run over three EPA drive cycles: 55mph, 65mph, and transient cycles

• Only up to 6 inputs are supplied by OEM, depending on regulatory subcategory

http://www.epa.gov/otaq/climate/gem.htm 6SAE INTERNATIONAL Inertial/Braking Aerodynamic Loss

Rolling Resistance Vehicle Auxiliary Loads Heat Rejection Exhaust Gas Friction Parasitic Loss Pumping Loss

Transmission Axles and Shaft



## • Phase II will consider all possible technologies that can be evaluated in a chassis dyno cell in order to improve engine and vehicle efficiency

• A significantly upgraded version of GEM is being developed and validated to account for all possible technologies mentioned above

• GEM is intended for demonstrating compliance with the standards rather than for research and development or any other purpose Total Engine Loss

7 

# Phase II GEMSAE INTERNATIONAL 

# Potential Assessment OptionsSAE INTERNATIONAL 

# Engine Technology

• Phase II GEM is being developed to account for all engine technologies that are tested in an engine dyno



### • Engine fuel map options

– Option A: a very well defined engine fuel could be developed from engine dyno testing and used in GEM

– Option B: alternative method of evaluating the engine other than a traditional engine fuel map

Inertial / Braking Aerodynamic Loss

Rolling Resistance Vehicle Auxiliary Loads Heat Rejection Exhaust

Gas Friction Parasitic Loss Pumping

Loss

Transmission Axles and

Shaft Total Engine Loss

9SAE INTERNATIONAL 

# Vehicle Technology

• OEM supplied aero drag and rolling resistance coefficients could be used to model the associated losses and

– Promote advanced aerodynamic technologies

– Encourage low rolling resistance tires

Inertial / Braking Aerodynamic Loss

Rolling Resistance Vehicle Auxiliary Loads Heat Rejection Exhaust

Gas Friction Parasitic Loss Pumping

Loss

Transmission Axles and

Shaft Total Engine Loss

10SAE INTERNATIONAL 

# Transmission Technology

• Transmissions, such as manual (MT), automated manual (AMT) and 

## automatic (AT), can be modeled within GEM

– Phase I GEM only model MT



## • GEM will allow OEM to enter transmission information, such as gear ratio vs. gear number

• GEM includes a shift strategy for each type of transmission

Inertial / Braking Aerodynamic Loss

Rolling Resistance Vehicle Auxiliary Loads Heat Rejection Exhaust

Gas Friction Parasitic Loss Pumping

Loss

Transmission Axles and

Shaft Total Engine Loss

11SAE INTERNATIONAL 

# Driveline Technology

• Axle modeling parameters, such as axle ratio, could be input by OEM

• A pull

- down menu could be specifically designed to recognize other axle technologies, such as 6x2 axle configurations

Meritor ECSA Smar 6x2 Dana’s dual range axle Inertial / Braking Aerodynamic Loss

Rolling Resistance Vehicle Auxiliary Loads Heat Rejection Exhaust Gas Friction Parasitic Loss Pumping

Loss

Transmission Axles and Shaft Total Engine Loss

12SAE INTERNATIONAL 

# Pull

- Down Menu Methodology

• A pull

- down menu approach can be specifically designed to 

## account for those technologies that are deemed inappropriate to model

– Axle technologies, such as Meritor ECSA Smar 6x2 and Dana’s dual range axle

– Transmission technologies, such as dual clutch transmissions or continuously variable transmissions



### – Lightweight material, such as high strength steel, aluminum, thermoplastic

– Predictive cruise control (look ahead/smart coast ...)

– Idle reduction

– Automated tire inflation systems

– Start

- Stop

Inertial / Braking Aerodynamic Loss

Rolling Resistance Vehicle Auxiliary Loads Heat Rejection Exhaust Gas Friction Parasitic Loss Pumping

Loss

Transmission Axles and Shaft Total Engine Loss

13SAE INTERNATIONAL 

# Phase II GEM Features

• Model upgrade examples

– Engine controller

• Engine fuel cut

- off algorithm during braking and deceleration

• More stable engine idle speed controller



## – Transmission model

• Manual Transmission

– upgraded

• Automatic Transmission

– newly developed

• Automated Manual Transmission

– newly developed



## – Driver model

• Distance

- Based Driver is developed and validated



## • Vehicle tests for model validation include over 130 vehicle variants

– Class 6 Vocational Box Truck with AT

– Class 6 Vocational Tow Truck with AT

– Class 8 T700 Tractor with AMT

– Class 8 Cascadia Tractor with MT

– Refuse Truck with AT 14SAE INTERNATIONAL 

# GEM Validation

– Class 8 T700 Tractor

• GEM has been validated against chassis dyno tests covering over 40 vehicle variants. GEM has been correlated to within +/

- 5% of the chassis test results 15SAE INTERNATIONAL 

# GEM Validation

- Class 6 Tow Truck

• GEM is validated against chassis dyno test over 40 vehicle variants. 

## Excellent agreements between GEM and tests have been obtained

.

16SAE INTERNATIONAL 

# GEM Validation

- Class 6 Box Truck

• GEM is validated against chassis dyno test over 40 vehicle variants. 

## Excellent agreements between GEM and tests are obtained

17SAE INTERNATIONAL 

# GEM Validation

– Refuse Truck

• GEM is validated against chassis dyno test over 6 vehicle variants. Good 

## agreements between GEM and tests have been obtained

18SAE INTERNATIONAL 

# GEM Validations against 130 Vehicle Variants

U.S. Environmental Protection Agency 

## • GEM has been validated against chassis dyno tests covering 130 vehicle 

## variants. Excellent agreements between GEM and tests have been obtained

.

19SAE INTERNATIONAL 

## • Driver behavior

— Pedal inputs

— Shift schedule



## • Transmission temperature 

# Chassis Testing Variability (1) Pedal Position % CO2 Mass Rate (kg/hr) Time (sec)

Time (sec) 7.34 7.53

7 7.1 7.2 7.3 7.4 7.5 7.6 7.7

35 55 75 95 Fuel Economy, MPG

Transmission Temperature, degC

CAC Temperature 46C

20SAE INTERNATIONAL 

## • Tire temperature 

# Chassis Testing Variability (2)

~270 N after 30 min. from cold

Average Tire Temperature Change = 9.7 degC Average Tire Pressure Change = 45 kPa

21SAE INTERNATIONAL 

## • Thermal management



## • Aftertreatment temperature

• Accessory load 

# Chassis Testing Variability (3)

Thermal management impact during idle Fueling Rate (L/hr)

Time (s) 22SAE INTERNATIONAL 

# Conclusions

• A full vehicle model

– GEM, has been developed and comprehensively validated against testing data covering 130 vehicle variants, and excellent agreement between GEM and tests has been obtained

• Variability in chassis dyno test results not only impact GEM 

## validations if not modeled correctly, but also impact test procedure considerations

• GEM is able to assess performance of those technologies that are being and will be developed at OEM level, which are intended to be put into production to reduce GHG emissions and improve fuel efficiency of heavy

- duty vehicles

• EPA is conducting Peer Review on Phase II GEM

23