Mitigation of Abnormal Injector Ticking Noise by Optimization of Hydraulic Operational Modes of Fuel System 2022-28-0096

With the advent of stricter regulation for tail pipe emission and urge to reduce the carbon foot prints, the engine hardware has undergone through evolutionary changes over the years i.e., boosting, low viscosity engine oil, high pressure fuel injection, cooled EGR, friction reduction, downsizing etc. These technological changes have led to the challenge of increase in radiated noise level from the engine (source) due to increased number of auxiliary drives on engine i.e., Turbo charger, HP fuel pump along with faster combustion & harsher operating conditions. The fuel system is one such system which has become most intricate with operating pressure going above 2000bar in the fuel rail and capability of up to 10 fuel injection per combustion. These changes in hardware could result in abnormal noise generation during specific operating conditions which may result in customer annoyance inside vehicle cabin.

This paper explains some of the abnormal intermittent noise sources in the engine and physical phenomenon which results in a ticking type noises which are usually observed during the low engine load and low rpm condition. The method such as Acoustic holography, beam forming, sound intensity could be used to identify noise source location by measuring the sound pressure field with multiple microphones. The measurement of the In-cylinder pressure, noise and vibration data and the experimentation with ECU parameters related to Fuel injection system could help in understanding the broad classification of noise i.e., engine parts knocking, combustion noise & actuator noise. Further this paper describes an approach to mitigate the ticking noise generated from fuel injection system through optimization of hydraulic operational modes of fuel system by ECU calibration parameter tuning.