Ford Global Technolgoies, LLC

James Alanoly

Bruce Howard Whittle

Arthur J Page

David M Fricke

David W Olson

Nabih Wassef Elsenety

A vehicle exhaust system test fixture integrates separate dynamic controls to provide at least twelve degrees of freedom (DOF). In one embodiment, two separate test tables are integrated so that one of the tables supports mounting of an engine/powertrain or apparatus simulating the engine/powertrain when coupled to an exhaust system. The other table supports mounting of the exhaust system to be tested. Each table is linked to a set of actuators/accelerometers to control motion up to 6 DOF. The capability of twelve DOF allows the test fixture to accurately reproduce both the dynamic behavior of a vehicle engine/powertrain during operation, and the dynamic behavior of the vehicle chassis during operation in the area where the exhaust system is attached to the vehicle frame. In addition, generated thermal profiles and high frequency external vibrations can be applied to allow simulation of real-world vibrations, and thermal stresses caused by hot exhaust gases. Another embodiment provides 12 DOF with a single test table rig arrangement. Yet another embodiment provides for greater than 12 DOF.

Dynamic test fixture for a vehicle exhaust system capable of twelve DOF

A method and system are provided for generating engine attachment control boundary conditions and corresponding control signals for an exhaust system laboratory test fixture which accurately reproduce both the dynamic behavior of a vehicle powertrain during operation, and the dynamic behavior of the vehicle frame during operation in the area where the exhaust system is attached to the vehicle frame. Road load data is collected in vertical, lateral, and longitudinal directions on the vehicle frame during vehicle operation at each of the locations where the exhaust system attaches. In addition, temperature and thermal cycling data are also collected during operation of the vehicle. The road load data is used to determine a best fit rigid body model. Accelerometer locations and directions are determined from statistical analysis and ranking to find the measures best fitting the determined rigid body. This information is then used to generate the test boundary conditions and control signals to be input to the test fixture. Thermal profiles are generated based on the collected temperature data to form input control signals to control heating of the exhaust system during testing. The generated thermal profiles allow simulation of real-world thermal stresses caused by hot exhaust gases.

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Farmington Hills, MI, United States of America

James Alanoly