Chapter 8 Starting system Section I Engine starting and method 1.Internal Combustion Engine Start Gasoline engine is at a temperature of 0-20 C,the minimum starting speed of 30-40r/min.In order to be at lower temperature of the engine that can be reliably started,it needs the starting speed ofnot less than 50-70r/min. Requirement for diesel engine starting speed is high,reaching 150-300r/min, otherwise poor atomization of diesel,gas mixture of poor quality,and to be difficulty in starting the engine.In addition,diesel engine compression ratio is larger than gasoline engine,and starting torque is also large,so diesel engine requires big starting power. 2.The Starting Method of Internal Combustion Engine (1)Human start. (2)Electric start. (3)Diesel engine started by gasoline engine. 机被与电子工程学原 Automobile and Tractor Northwest A&F University
Automobile and Tractor Northwest A&F University Chapter 8 Starting system 1. Internal Combustion Engine Start Gasoline engine is at a temperature of 0-20 ℃, the minimum starting speed of 30-40r/min. In order to be at lower temperature of the engine that can be reliably started, it needs the starting speed of not less than 50-70r/min. Requirement for diesel engine starting speed is high, reaching 150-300r/min, otherwise poor atomization of diesel, gas mixture of poor quality, and to be difficulty in starting the engine. In addition, diesel engine compression ratio is larger than gasoline engine, and starting torque is also large, so diesel engine requires big starting power. 2. The Starting Method of Internal Combustion Engine (1) Human start. (2) Electric start. (3) Diesel engine started by gasoline engine. Section 1 Engine starting and method
Chapter 8 Starting system Section 2 Electric start system The meshing mechanism of electric starter There are two commonly used types: (1)lever type (2)electromagnetic type .5-3m Figure 8.1 Electromagnetic engaging mechanism 1.starting switch 2.fixed contact 3.dynamic contact bridge 4.retaining coil 5.suction pull coil 6.iron core 7.tie rod 8.transmission fork 9.one-way clutch 10.drive gear 11.armature 12.wire brush 13. magnetic pole 械电子工程学 Automobile and Tractor Northwest A&F University
Automobile and Tractor Northwest A&F University Chapter 8 Starting system The meshing mechanism of electric starter There are two commonly used types: (1) lever type (2) electromagnetic type Figure 8.1 Electromagnetic engaging mechanism 1. starting switch 2. fixed contact 3. dynamic contact bridge 4. retaining coil 5. suction pull coil 6. iron core 7. tie rod 8. transmission fork 9. one-way clutch 10. drive gear 11. armature 12. wire brush 13. magnetic pole Section 2 Electric start system
Chapter8 Starting system Section 3 Starting auxiliary device Usually two ways to improve startup performance:the one is to lower engine starting resistance;the second is to improve the fire conditions. 1.Start Decompressing Mechanism Because diesel engine compression ratio and start-resistance is large,cylinder compressure can be reduced by opening the valve.Decompressing mechanism can complete this method. 2.Electric Heating Plug In the swirl chamber or pre-combustion chamber of diesel engine,the combustion chamber is equipped with electric heating plugs,which warm up the air in the combustion chamber at the start. 3.Intake Preheater In the medium power diesel engines,the intake preheater is used as a cold start preheating device. 4.Starting Fluid Spurting Device According to the need,in some diesel engine can use starting fluid spurting device 机被寿电子工程学模 Automobile and Tractor Northwest A&F University
Automobile and Tractor Northwest A&F University Chapter 8 Starting system Usually two ways to improve startup performance: the one is to lower engine starting resistance；the second is to improve the fire conditions. 1. Start Decompressing Mechanism Because diesel engine compression ratio and start-resistance is large, cylinder compressure can be reduced by opening the valve. Decompressing mechanism can complete this method. 2. Electric Heating Plug In the swirl chamber or pre-combustion chamber of diesel engine, the combustion chamber is equipped with electric heating plugs, which warm up the air in the combustion chamber at the start. 3. Intake Preheater In the medium power diesel engines, the intake preheater is used as a cold start preheating device. 4. Starting Fluid Spurting Device According to the need， in some diesel engine can use starting fluid spurting device. Section 3 Starting auxiliary device
Chapter 9 Gasoline ignition system Section 1 Requirements and classification The engine ignition has three ways of hot fire ignition,compression ignition and electric spark ignition.Diesel engines use compression ignition,and gasoline engines generally use electric spark ignition. 1.The Requirements of The Ignition System (1)It can produce enough high-voltage 15-20kV to puncture spark plug gap. (2)Spark plug should have enough energy 50-80MJ. (3)Ignition timing should be adapted to the work of the engine. 2.Classification of The Ignition System (1)Conventional ignition system. (2)Semiconductor ignition system. (3)Computer controlled ignition system. (4)Magneto ignition system. 机械电子工程学度 Automobile and Tractor Northwest A&F University
Automobile and Tractor Northwest A&F University Chapter 9 Gasoline ignition system The engine ignition has three ways of hot fire ignition, compression ignition and electric spark ignition. Diesel engines use compression ignition, and gasoline engines generally use electric spark ignition. 1. The Requirements of The Ignition System (1) It can produce enough high-voltage 15-20kVto puncture spark plug gap. (2) Spark plug should have enough energy 50-80MJ. (3) Ignition timing should be adapted to the work of the engine. 2. Classification of The Ignition System (1) Conventional ignition system. (2) Semiconductor ignition system. (3) Computer controlled ignition system. (4) Magneto ignition system. Section 1 Requirements and classification
Chapter 9 Gasoline ignition system Section 2 Traditional ignition system 1.The Composition of Traditional Ignition System (1)power 10 (2)ignition switch (3)ignition coil (4)distributor @ (5)capacitor (6)spark plug ood (7)high voltage wire 莓昏香草 Figure 9.1 The composition of traditional ignition system 1.ignition switch 2.ammeter 3.accumulator 4.starter 5.high-voltage conductor 6.damping resistor 7.spark plug 8.circuit breaker 9.capacitor 10.ignition coil 11.additional resistor 12.distributor 业机械与电子工程模 Automobile and Tractor Northwest A&F University
Automobile and Tractor Northwest A&F University Chapter 9 Gasoline ignition system 1. The Composition of Traditional Ignition System (1) power (2) ignition switch (3) ignition coil (4) distributor (5) capacitor (6) spark plug (7) high voltage wire Figure 9.1 The composition of traditional ignition system 1. ignition switch 2. ammeter 3. accumulator 4. starter 5. high-voltage conductor 6. damping resistor 7. spark plug 8. circuit breaker 9. capacitor 10. ignition coil 11. additional resistor 12. distributor Section 2 Traditional ignition system