ISC, ISCe, QSC8.3, ISL, ISLe3, ISLe4 and QSL9 Engines – 014-002   Engine Testing (Chassis Dynamometer)

Table of Contents

Setup
Test

Setup

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The performance of an engine installed in on-highway vehicles can be tested on a chassis dynamometer.

NOTE: Because of driveline efficiency and engine-driven accessories, the engine horsepower when measured at the rear wheels will be reduced by approximately:

  • 20 percent for single-axle vehicles
  • 25 percent for tandem-axle vehicles
  • 35 percent for recreational vehicles.

NOTE: These percentages are used for engine run-in only and are not to be used as absolute figures.

 
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 WARNING 

Follow all of the vehicle manufacturer’s safety precautions before installing or operating a vehicle on a chassis dynamometer. Failure to do so can cause damage to the vehicle and/or harm personnel.

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 CAUTION 

Low-profile tires are more sensitive to heat than bias ply tires. Excessive operating time at full load can damage the tires due to overheating. Check the tire manufacturer’s recommendations for the maximum allowable chassis dynamometer operating time.

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While operating the chassis dynamometer, follow the general safety precautions listed below:

  • Use tires that have more than 160 km [100 mi] of use. Do not use new tires.
  • Do not use recapped tires or tires of different sizes or designs.

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  • Make sure the tires are inflated to the manufacturer’s specifications.
  • Remove all rocks or other materials from the treads of the tires that will be rotating on the dynamometer rollers.

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  • Make sure there is correct overhead clearance for exhaust stacks, air deflectors, or other attachments above the cab.

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 CAUTION 

To prevent damage to the chassis dynamometer, make sure there is enough slack in the tie-down chains.

Carefully position the vehicle on the rollers.

Attach the tie-down chains to the rear of the vehicle.

Place wheel chocks in front of the front tires.

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 WARNING 

Some exhaust gas constituents may be toxic and/or carcinogenic. Make sure the ventilation hose does not leak.

Adjust the vehicle and dynamometer room exhaust system to make sure all the exhaust gases are removed from the room.

Read the chassis dynamometer and vehicle manufacturer’s recommendations and specifications for testing procedures.

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Test

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 WARNING 

Check the coolant level only when the engine is stopped. Wait until the coolant temperature is below 50°C [120°F] before removing the pressure cap. Failure to do so can cause personal injury from heated coolant spray.

The following procedure assumes that the lubricating oil and fuel systems were correctly primed, the dipstick calibrated, and the engine filled to the correct levels with lubricating oil and coolant during installation of the engine into the chassis. If these systems were not serviced during installation of the engine.

Use the following procedures for instructions on priming the lubricating oil and the fuel system and calibrating the dipstick.

Reference the Operation and Maintenance Manual for instructions on filling the lubricating oil and the cooling systems.

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The number of instruments and gauges required to perform a chassis dynamometer test will vary according to type and the capability of the test equipment used.

See the service tools listed at the beginning of this section.

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To correctly monitor an engine’s performance, record the following parameters:

 
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Last Modified:  08-Jul-2009