Reducing Inertial Noise for Injector Testing

CASE STUDY: Reducing Inertial Noise for Injector Testing

PROBLEM: Distorted Test Results caused by RPM Fluctuation


We needed to mimic the inertia of a diesel engine driveline in a test bench said Brian Nugent - MCM Inc., Engineering Manager. This particular application we chose a 400 lb flywheel. The flywheel was mounted to a shaft that needed to be coupled to a custom camshaft that is actuating a fuel injector. One of the challenges was the stiffness of the coupling. We have found that if the coupling has wind up, even with zero backlash, it will affect how the test is performed by allowing the instantaneous rpm to droop momentarily within part of a revolution.

MCM chose an R&W coupling, custom model for this application - the adapters were custom to fit the different shaft sizes and the shaft locks we used.

It was known when sizing this coupling that the commercially available off the shelf part could not handle as much torque as a previous disc type coupling used, but the stiffness was higher. After installing the initial Bellows BK, an instrument was used to see how much phase change is seen during operation from one side of the coupling to the other. The coupling showed 1/3 of the phase difference, or wind up, compared to the previous couplings used. This resulted in more consistent testing of the fuel injector.

Since 1994, Michigan Custom Machines (MCM) has emerged as a world-class leader in the design and build of advanced custom test machines for automotive and industrial component manufacturers. The MCM team offers customers leading expertise in turnkey component testing equipment for in line and end of line production requirements as well as laboratory and R&D.

Our extensive client list includes major fortune 500 companies and tier 1 component suppliers. Whether you call it a bench, rig, stand, rack or machine, we have designed and built hundreds of them to test many different components including cam phasers, fuel injectors, pumps, turbochargers, charge air coolers, radiators, pressure transducers, solenoid valves, engine control valves, transmission devices and much more.

MCM Sales Contact:

Craig R Antenucci

Vice President Sales & Marketing


O. 248.347.7900 x300

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