Method of Fuel Injection in Small Diesel Engines

Abstract

Small diesel engines with power up to 10 kW are widely used as autonomous, compact and mobile power sources for various machines. These engines mostly employ mechanically actuated fuel feed systems. This type of systems hasn’t been used in modern diesel engines with relatively large power because of the incapability of such systems to provide conforming to the existing ecological standards. These standards are easier for small diesels but further tightening of ecological standards would make the modernization of traditional systems necessary. As a way of modernization the method of fuel injection into diesel engine cylinder based on speed forcing of HPFP is proposed. At speed forcing two plunger strokes correspond to one operational stroke of engine cylinder. The first stroke is used for fuel feed into the cylinder. The second stroke can be used for creating optimal fuel pressure (initial pressure) in the system before feeding it into cylinder during main plunger stroke. The results of computational and experimental studies show that the proposed method of fuel feed is effective for fuel feed system of small-displacement one-cylinder engine Kipor KM186FA. It was determined that fuel pressure in the system increased 1.42 times at calculated increasing of maximal injection pressure 1.46 times. HPFP drive elements loading increased by 20 percent at that. Also the use of the method of fuel injection with speed forcing of HPFP allows controlling the initial pressure in the system for the optimization of fuel feed characteristics.