Chapter 4 Diesel fuel supply system Section 2 Mixture formation and combustion chamber (1)"@"combustion chamber Features:Simple and compact structure,small area of heat dissipation,high thermal efficiency,better economy,better startup performance.For high injection pressure,often using small porous nozzle injector,high cleanliness requirements for diesel,work more brutally. Injection pressure:18-25KPa Jet hole:0.25-0.4mm 4-8jet holes. (2)sphere combustion chamber Features:The engine works relatively soft than "o"combustion chamber,but the start is more difficult. Injection pressure:17-22KPa Single hole diameter:0.5-0.7mm,Double holes diameter:0.3-0.5mm. 械电子工程学 Automobile and Tractor Northwest A&F University
Automobile and Tractor Northwest A&F University Chapter 4 Diesel fuel supply system (1) "ω" combustion chamber Features: Simple and compact structure, small area of heat dissipation, high thermal efficiency, better economy, better startup performance. For high injection pressure, often using small porous nozzle injector, high cleanliness requirements for diesel, work more brutally. Injection pressure : 18－25KPa，Jet hole : 0.25－0.4mm，4－8 jet holes. (2) sphere combustion chamber Features: The engine works relatively soft than "ω" combustion chamber, but the start is more difficult. Injection pressure: 17-22KPa，Single hole diameter: 0.5-0.7mm, Double holes diameter: 0.3-0.5mm. Section 2 Mixture formation and combustion chamber
Chapter 4 Diesel fuel supply system Section 2 Mixture formation and combustion chambep 2.2 Separate combustion chamb Features:Due to the strong vortex flow,the usage of air is high,and a is small.In addition,the engine works soft and is not sensitive to the changes of speed,and the combustion is complete with little exhaust pollution However,the area of heat dissipation is big,with throttle losses,poor economy, and high fuel consumption rate. Moreover,cold start is more difficult Injection pressure:12-14 Kpa, 0=1.1-1.3. Figure 4.4 Separate combustion chamber (a)turbulence combustion chamber (b)precombustion chamber 机被电子工程聚 Automobile and Tractor Northwest A&F University
Automobile and Tractor Northwest A&F University Chapter 4 Diesel fuel supply system 2.2 Separate combustion chamber Features: Due to the strong vortex flow, the usage of air is high, and α is small. In addition, the engine works soft and is not sensitive to the changes of speed, and the combustion is complete with little exhaust pollution. However, the area of heat dissipation is big, with throttle losses, poor economy, and high fuel consumption rate. Moreover, cold start is more difficult. Injection pressure: 12-14 Kpa， α＝1.1-1.3. Figure 4.4 Separate combustion chamber (a) turbulence combustion chamber (b) precombustion chamber Section 2 Mixture formation and combustion chamber
Chapter 4 Diesel fuel supply system Section 3 Fuel injector The function of the injector is to spray the high-pressure diesel from fuel injection pump into the combustion chamber according to certain requirements.Injector is divided into t two categories,namely open and closed fuel injector. The closed fuel injector has two common types of hole and pintaux. 1.Hole injector Hole injector is mainly used for the direct injection of combustion chamber.The range of the number of holes is generally 1-8,and the hole diameter is 0.25-0.8mm. Figure 4.5 Hole injector 机电子工程膜 Automobile and Tractor Northwest A&F University
Automobile and Tractor Northwest A&F University Chapter 4 Diesel fuel supply system The function of the injector is to spray the high-pressure diesel from fuel injection pump into the combustion chamber according to certain requirements. Injector is divided into two categories, namely open and closed fuel injector. The closed fuel injector has two common types of hole and pintaux. 1. Hole injector Hole injector is mainly used for the direct injection of combustion chamber. The range of the number of holes is generally 1-8, and the hole diameter is 0.25-0.8mm. Figure 4.5 Hole injector Section 3 Fuel injector
Chapter 4 Diesel fuel supply system Section 3 Fuel injector (b) Figure 4.6 The working process of hole injector schematic diagram (a)fuel injection (b)close Automobile and Tractor Northwest A&F University
Automobile and Tractor Northwest A&F University Chapter 4 Diesel fuel supply system Figure 4.6 The working process of hole injector schematic diagram （a）fuel injection （b）close Section 3 Fuel injector
Chapter 4 Diesel fuel supply system Section 3 Fuel injector 2.Pintaux Injector Pintaux injector is usually used for separate combustion chamber.It usually has only one hole, and the hole diameter is 1-3mm. 1.oil return pipe bolt 2.pressure adjusting screw helmet 3.pressure adjusting screw 4.pressure adjusting spring 5.oil injector body 6.fuel inlet pipe 7.tapered rod 8.fastening nut sleeve 9.fuel inlet pipe of injection nozzle 10.needle valve 11.needle valve body 10 Figure 4.7 Pintaux injector Automobile and Tractor Northwest A&F University 电子用
Automobile and Tractor Northwest A&F University Chapter 4 Diesel fuel supply system 2. Pintaux Injector Pintaux injector is usually used for separate combustion chamber. It usually has only one hole, and the hole diameter is 1-3mm. Figure 4.7 Pintaux injector 1. oil return pipe bolt 2. pressure adjusting screw helmet 3. pressure adjusting screw 4. pressure adjusting spring 5. oil injector body 6. fuel inlet pipe 7. tapered rod 8. fastening nut sleeve 9. fuel inlet pipe of injection nozzle 10. needle valve 11. needle valve body Section 3 Fuel injector