Novel Test Method for Accelerated Fatigue Testing of Engine Camshaft

In some IC engines, fuel injection pump is driven by camshaft; thus, these camshafts are designed for bending and torsional loads. Conventionally, camshafts are built-to-specification. Typically, durability assessment of camshafts happens at engine level, this calls for proto or calibration engine to be made and available for testing. As there are limited number of engine level proto testing, the overall scatter in camshafts due to manufacturing/process variations is not possible to be covered. This poses a risk of camshaft failures in the final stages of product development. To mitigate this risk, a component level standard test method is needed for quickly validating design and manufacturing process of camshafts for second source suppliers. The current paper discusses the process followed for arriving at a standard test setup and the challenges in terms of capturing the appropriate physics. Camshaft rear end experiences bending load due to FIP operation, and this bending load is applied through rigid actuator in test. To ensure repeatability in test, ensuring load and bending moment is one of the primary requirements. This developed test setup was used for validating improvements done on manufacturing process and design quickly with confidence for design implementation approval for a test concern. Strain measurement was performed on camshaft with the proposed test setup and found to have more than 98% correlation with CAE results. Newly developed test methodology is added as a DVP requirement for all upcoming projects. This benefited time savings around 120 days per project for camshaft testing.