For high degree of engine performance, it is imperative that all critical parts are designed and optimised through durability assessment. The conventional engine development programme based on actual engine test on test bed is time consuming and expensive, and is being replaced by use of simulation tools and accelerated component testing.
The present work is a systematic fatigue strength evaluation programme for connecting rod of an up-rated Naturally Aspirated, Direct Injection, Inline Diesel Engine
The established staircase method of fatigue test is slightly modified to minimise the effect of scatter in the results and to arrive at a consistent and dependable factor of safety.
Also analytical tools like Finite Element Analysis (FEA) and Statistical Techniques were used; which helped to keep design and tooling iterations to a minimum and facilitated connecting rod development in the given time frame. The fatigue test results correlated well with FEA results in determining the factor of safety.
The most important point observed in the present work is the importance of correct test conditions, dimensional control of test fixture and alignment of the connecting rod with the actuator. These variables have marked influence on the test results causing larger scatter and can cause unnecessary design alterations