scope:

Introduction

Note: Nothing in this standard supercedes applicable laws and regulations.

Note: In the event of conflict between the English and domestic language, the English language shall take precedence.

Purpose. This procedure evaluates the structural durability of passenger car, sport utility vehicle, and truck (light and medium duty) exhaust systems when subjected to real-time load and displacement profiles simulating proving ground road test modules. This procedure describes the test development and durability test execution.

Applicability.

This procedure is applicable to all passenger cars, sport utility vehicles, and trucks (light and medium duty) equipped with an exhaust system.

This procedure is used to develop or validate the structural durability of a vehicle exhaust system. Exhaust system components that are not sensitive to fatigue damage from road inputs may not experience the same level of correlation.

This procedure does not provide a total exhaust system structural durability test. Degradation or failure modes related to environmental factors such as corrosion, humidity and dust are not simulated. Powertrain inputs such as engine firing pulses, engine vibration, exhaust gas backpressure, and exhaust gas thermal duty cycles associated with a running engine are not simulated on tests using a natural gas furnace/burner.

Exhaust hanger insulators are known to wear prematurely during durability test execution due to excess internal heat generation, which is not dissipated as in normal vehicle operation. Therefore, such components are usually monitored and replaced as necessary during the durability test. If external cooling is determined to be necessary by the test requester and test engineer, a compressed air cooling system or electric fans can be used to provide airflow over the exhaust hanger insulator during durability test execution.