What are the reasons for the fluctuating throttle in a single-cylinder diesel engine?
1 Answers
Common causes of unstable diesel idle speed include: 1. Excessive air leakage: During idle, significant air leakage in the cylinder leads to high energy loss, resulting in lower compression temperature and pressure, poor fuel atomization, and significant combustion fluctuations. 2. Insufficient fuel supply: The small fuel supply during idle means that minor variations in fuel supply to each cylinder can cause different operating conditions. This uneven fuel distribution among cylinders during idle can lead to the 'idle hunting' phenomenon in diesel engines. 3. Unstable fuel supply: The direct injection in diesel engines has led to higher injection pressures, especially with the use of multi-hole injectors. This makes the nozzle less precise when supplying small amounts of fuel, prone to fluctuations. Unstable fuel supply is a major cause of unstable idle speed. 4. System aging: Prolonged use and aging of the fuel injection system cause differences in components like injectors and delivery valves among cylinders, leading to further uneven fuel distribution and exacerbating idle speed fluctuations.