Innovative Approach of Reducing Vibration Stress in High Pressure Fuel Injection Pipe and Fuel Injector Using Vibration Dampers in Two Cylinder Diesel Engine

Design and development of high-pressure pipe involves number of design validation plans for robust design in diesel engine. The fundamental behavior of two-cylinder diesel engine with parallel stroke involves high vibration which generates stress on components mounted on crankcase resulting into earlier fatigue failure. In this paper, the innovative approach of using optimized design of vibration damper for resolving high vibration stress concerns in fuel system is discussed. The vibration dampers were designed meeting both performance and durability aspects in two-cylinder diesel engine applicable for both passenger and commercial vehicle. This paper highlights the design approach involving experimental stress measurements and design optimization based on part development feasibility. We measured the vibration stress of the complete fuel system on engine test bench as well as in vehicle chassis dyno at different loads and engine speed to confirm the existence of resonance phenomenon in both conditions of with and without vibration dampers added in high pressure fuel injection pipe. Without vibration dampers, maximum vibration stress value measured was 154 MPa in fuel injection pipe exceeding design limit of 100 MPa. With the help of improved design having evaluated weight configuration of vibration dampers, the stress was reduced drastically to 52 MPa resolving the high risk of fuel system breakage. This paper also deals with validation approach to evaluate fuel system with vibration dampers in both test bed and vehicle level at different duty cycles to confirm on design validation before implementation.