Engine Benchmark 

Cummins ISB 6.7 and Navistar N13

Southwest Research Institute

11-December-2014
Outline

• Medium Duty

– HIL to Engine Conversion

– Powertrain & Engine Correlation

– Engine Fuel Mapping

 Ramped Modal vs. Steady State

– Engine Benchmarking

• Heavy Duty

– Engine Fuel Mapping

– Engine Benchmarking

– Engine to HIL Conversion

11-Dec-2014 2
Medium Duty HIL to Engine 

Conversion & Correlation

11-Dec-2014 3
MD Engine Test Setup

• Cummins ISB10 6.7 I6

– Tested 300 hp and 240 hp 

ratings

• Taken out of an F650 flat 

bed tow truck

• HP common rail 

• Single VGT turbo 

• Cooled EGR

• DOC/DPF/SCR

• 2010 Emission Compliant

11-Dec-2014 4
HIL to Conventional Engine Testing Setup

• Conversion to engine dynamometer configuration

– Removed transmission

– Disabled “Max Engine Speed without VSS” via Cummins Insite Software

– Connected transmission electrical connectors to disable “Powertrain Protection Status”

 Needed a vehicle speed sensor

11-Dec-2014 5
ISB Torque and Power Map

ISB 6.7 CM2250 rating:

Peak Power: 224 kW @ 2600 rpm

Peak Torque: 895 N-m @ 1600 rpm

SwRI Measured:

6

0

20

40

60

80

100

120

140

160

180

200

220

240

0

100

200

300

400

500

600

700

800

900

1000

750 1000 1250 1500 1750 2000 2250 2500 2750

Power [kW]

Torque [N-m]

Engine Speed [rpm]

F650 Cummins ISB 224 kW Rating

Torque N-m

Power kW

11-Dec-2014
Correlation With Powertrain Setup

• Select points from previous powertrain SET were used to 

correlate engine performance under steady-state conditions.

– Engine speed and pedal position values matched

– Both setups resulted in comparable engine and emission performances

 Engine setup does not appear to be limited by other software limitations i.e. de-rate, fuel economy modes, etc.

– Engine curb idle torque was also determined by matching fuel consumption 

7

1 2 3 4 5 6 7

Fuel Flow [kg/hr]

Modes

CITT Fuel 

Matching: 80 N-m 

1 2 3 4 5 6 7

EO NOx Sensor [ppm] 

Modes

1 2 3 4 5 6 7

Output Torque [N-m] 

Modes

Engine Powertrain Engine_Est

Transmission 

Losses 

11-Dec-2014
Medium Duty Engine Fuel 

Mapping & Benchmarking

11-Dec-2014 8
ISB Engine Fuel Mapping

• Speed [rpm]: 750, 900, 1050, 1200, 1350, 1500, 1650, 1800, 

 1950, 2100, 2250, 2400, 2550, and 2650

• Load [%]: 100, 90, 75, 60, 50, 35, 25, 10, 5, and 0

9

0

200

400

600

800

750 950 1150 1350 1550 1750 1950 2150 2350 2550 2750

Engine Torque [N-m]

Engine Speed [RPM]

ISB 300 hp Fuel Mapping Points

11-Dec-2014
ISB Engine Fuel Mapping

• Modern engines have layers of sophisticated controls which 

change engine fueling subject to different operating conditions

– Fuel economy optimization

– Volumetric efficiency compensation

– Combustion phasing

– Thermal management

– Soot control

– Rail pressure dynamic

– DPF regeneration

– Altitude

– And many more optimization strategies

11-Dec-2014 10
ISB Engine Fuel Mapping

• Two methods were explored while mapping fuel rates

– Traditional steady state fuel mapping (~5 min or longer at each mode)

– Ramp modal fuel mapping (20 sec ramps and 60 sec at each mode before sampling)

11

Ramp Modal Fuel Mapping Example:

11-Dec-2014
Fuel Flow (Avg) kg/hr Torque (N-m)

Speed (RPM)

Fuel Flow (Avg) kg/hr Torque (N-m)

Speed (RPM)

ISB Engine Fuel Mapping

• Ramp Modal

12

• Steady-State

Fueling Differences at light loads 

11-Dec-2014
ISB Fuel Mapping

13

• Ramp modal – Steady-State Fueling:

-1.2

1.8

0.0

1.2

-0.60 0.60 0.0

0.0

0.0

0.0

-0.60

-1.2

1.8

0.0

1.2

-0.60 0.60 0.0

0.0

0.0

0.0

-0.60

-1.2

1.8

0.0

1.2

-0.60 0.60 0.0

0.0

0.0

0.0

-0.60

-1.2

1.8

0.0

1.2

-0.60 0.60 0.0

0.0

0.0

0.0

-0.60

-1.2

1.8

0.0

1.2

-0.60 0.60 0.0

0.0

0.0

0.0

-0.60

-1.2

1.8

0.0

1.2

-0.60 0.60 0.0

0.0

0.0

0.0

-0.60

-1.2

1.8

0.0

1.2

-0.60 0.60 0.0

0.0

0.0

0.0

-0.60

-1.2

1.8

0.0

1.2

-0.60 0.60 0.0

0.0

0.0

0.0

-0.60

-1.2

1.8

0.0

1.2

-0.60 0.60 0.0

0.0

0.0

0.0

-0.60

-1.2

1.8

0.0

1.2

-0.60 0.60 0.0

0.0

0.0

0.0

-0.60

-1.2

1.8

0.0

1.2

-0.60 0.60 0.0

0.0

0.0

0.0

-0.60

-1.2

1.8

0.0

1.2

-0.60 0.60 0.0

0.0

0.0

0.0

-0.60

-1.2

1.8

0.0

1.2

-0.60 0.60 0.0

0.0

0.0

0.0

-0.60

-1.2

1.8

0.0

1.2

-0.60 0.60 0.0

0.0

0.0

0.0

-0.60

-1.2

1.8

0.0

1.2

-0.60 0.60 0.0

0.0

0.0

0.0

-0.60

-1.2

1.8

0.0

1.2

-0.60 0.60 0.0

0.0

0.0

0.0

-0.60

800 1000 1200 1400 1600 1800 2000 2200 2400 2600

0

100

200

300

400

500

600

700

800 Fuel Flow Diff Torque (N-m)

Speed (RPM)

-3.0

-2.4

-1.8

-1.2

-0.60

0.0

0.60

1.2

1.8

2.4

3.0

Fueling Differences 

at light loads 

• The two methods yield nearly identical fueling rates, except at 

light loads when exhaust temp falls below 200 degC. 

100

150

200

250

300

350

400

450

500

0

2

4

6

8

10

12

14

5000 5250 5500 5750 6000

Exhaust Temp [degC]

Fuel Flow [kg/hr]

Time [sec]

Fuel Flow kg / hr

Exhaust T degC

Thermal Mgt Starts

Fueling reduces as exhaust 

temp exceeds 250 degC

11-Dec-2014
ISB Motoring Curves

• Engine pre-conditioning greatly impacts motoring results

14

Torque [N

-m]

Engine Speed [RPM]

Torque N-m (SS)

Torque N-m (Ramp1)

Torque N-m (Ramp2)

Torque N-m (Ramp3)

Measured friction is lower 

due to a change in air flow strategy

Intake Air Flow [kg/hr]

Engine Speed [RPM]

Torque N-m (SS)

Torque N-m (Ramp1)

Torque N-m (Ramp2)

Torque N-m (Ramp3)

10 min Rated – 2nd Ramp 

10 min Rated – 1st Ramp 

11-Dec-2014
ISB Benchmark: FTP, SET, WHTC & ARB

• SwRI finished CO2/fuel measurement over the FTP, WHTC, and ARB cycles 

on the 300 hp rating (cold-start and hot starts)

• Cycle results [g/kW-hr] : 

• BSCO2COV ~ 0.5%

11-Dec-2014 15
Navistar N13 Engine Fuel 

Mapping & Benchmarking

11-Dec-2014 16
Navistar N13 Engine Setup

17

• Navistar N13

– Tested 475hp, 450hp, and 

410 hp ratings

• Primarily class 8 

commercial truck

• HP common rail 

• Inter-stage cooled

sequential turbo 

• Cooled EGR

• DOC/DPF/SCR

• 2010 Emission Compliant

11-Dec-2014
Navistar N13 Engine Setup

11-Dec-2014 18
N13 Fuel Mapping

19

• Ramp modal fuel mapping 

only, based on medium 

duty results

11-Dec-2014

Fuel Flow [kg/hr] Torque 1 (Avg) (N-m)

Speed (Avg) (RPM)
N13 Benchmark: FTP, SET, WHTC & ARB

• SwRI conducted transient cycles to be used for 

later studies

– FTP, WHTC, ARB, FTP

11-Dec-2014 20
Navistar N13 HIL Configuration

21

• Installed automated manual transmission

• Collaborative ongoing effort to complete powertrain 

benchmarking

11-Dec-2014
Summary

• SwRI converted & correlated medium duty 

powertrain to engine configuration

– Completed two methods of engine fuel mapping, 

and engine benchmarking on FTP, ARB, WHTC, and 

SET cycles

• SwRI completed engine benchmarking of 

heavy duty Navistar N13

• Continuing with powertrain benchmarking

11-Dec-2014 22
Questions?

11-Dec-2014 23