Engine roughness, block vibration and external noise of diesel engine running on Jojoba biodiesel and diesel blends

An experimental investigation has been carried out to examine the engine roughness including combustion generated noise, overall external noise and block vibration of a direct-injection diesel engine running on biofuel derived from Jojoba oil and blends with diesel fuel. The physiochemical properties of the biofuel are presented including density, viscosity and distillation data. The engine used is Lister Petter single cylinder DI diesel engine equipped for performance parameters, external noise, and block vibration. The Jojoba biofuel / diesel blend ratio was varied from 0 %, 25 %, 50 %, 75 % and 100 %. The data were collected at different engine operating conditions of load, and engine speed at fixed injection timing and compression ratio. The vibration and noise data have been related to the pressure data to represent the engine roughness for both cases of diesel and biodiesel. Ensemble averaged data of vibration cycle, along with rms and maximum vibration and noise are presented at different engine speeds and fuel conditions. Jojoba biodiesel case exhibited slightly higher maximum combustion pressure rise rate and maximum combustion pressure or higher combustion noise compared to the diesel case. This is also evidenced by the higher maximum and rms vibration for pure Jojoba biofuel compared to pure diesel. Average cycle noise and maximum cycle noise was also higher for Jojoba biofuel compared to pure diesel or Jojoba biofuel/diesel blends.