Progress in electronic fuel injection control systems for automotive diesel engines

The fuel injection timing and the fuel quantity are two of the major parameters to be precisely controlled to optimise diesel engine. This paper presents a new electronic injection timing control based on direct sensing of the start of combustion. Although the injection timing is usually optimised against engine rpm and load, it is also affected by the atmospheric pressure, coolant temperature, fuel properties and injection rate deterioration. By using a start–of–combustion sensor the influence of these parameters on injection timing can be compensated for and the engine performance can be recovered. A new fuel quantity control has been also developed. Instead of 'spill ring' control, an electronic magnetic valve with fast response has been adopted, which enables more precise control of the amount of fuel injected.