What are the reasons for unstable idle speed in a single-cylinder diesel engine?
1 Answers
Single-cylinder diesel engine idle speed instability reasons are as follows: Excessive cylinder leakage during idle: Increased energy loss within the cylinder results in lower compression temperature and pressure, poor fuel atomization, and significant combustion fluctuations. Small fuel supply during idle: Minor variations in fuel supply to each cylinder can lead to different working conditions among cylinders. This uneven fuel distribution during idle causes diesel engine idle hunting. Nozzle imprecision in fuel delivery: The direct injection trend in diesel engines has led to higher injection pressures, particularly with multi-hole injectors. This makes nozzle precision unstable when delivering small fuel quantities, prone to fluctuations. Extended usage and fuel injection system aging: Creates disparities among components like injectors and delivery valves across cylinders, exacerbating fuel supply unevenness and intensifying idle speed fluctuations.