Study On Cold Start Of Electronic Controlled CA498Z Diesel Engine

Under the stress of saving energy, and environment protection, studieson electronic controlled diesel engine are of great significance. EuropeanCommunity is enforcing stricer and stricter vehicle emissions regulations.In addition to lower emissions requirement, test procedures are alsoupdated. The first 40 seconds originally without taking emissionsmeasurement now must be taken into consideration. So it is meaningful tolower the emissions during the course of coldstart of diesel engine.In this thesis, with the engine produced by DaLian diesel engine works,whose model is CA498Z and the high pressure fuel pump produced byBOSCH Company, whose model is VP37 to be combined in an electroniccontrolled diesel engine, a lot of experiments were done to decrease HCemission and increase reliability of the electronic controlled engine in coldstart operating condition by using the demarcate system named VS100which is produced by BOSCH company. The general way to optimize fuelsupply map and the flow program of start process was also educed. Themain work in this thesis includes:1. The test-bed of coldstart was designed and made.2. On the diesel engine made by DaLian diesel engine works, whosemodel is CA498Z and the high pressure fuel pump produced by BOSCHCompany, whose model is VP37 to be combined in an electronic controlleddiesel engine was used, the engine's advanced angle of fuel supply wasmeasured and adjusted.3. The electronic control unit of the electronic controlled diesel enginewas designed and exploited.4. Fuel supply map was demarcated and optimized in the course ofcoldstart process of the combined electronic controlled diesel engine byusing the demarcate system named VS100 which is produced by BOSCHCompany.5. The influence of end symbol rotate speed of coldstart to start timeand HC emission was analysed and researched through experiments.6. The influence of engine coolant temperature to start time and HCemission analysed and researched through experiments.7. The influence of intake air heater to start time and HC emission wasanalysed and researched through experiments.8. The influence of voltage's variety to start time and HC emission wasanalysed and researched through experiments.9. The influence of battery voltage's drop during the cours of coldstartbecause of environment temperature was analysed and researched.10. The influence of heatting fuel pipe to start time and HC emissionwas analysed and researched through experiments.11. Strategy of coldstart for electronic controlled diesel engine wasreserched.Experiment results show that:1. More or lower quantity of fuel supply during the coldstart processmakes against start time and HC emission.2. On the condition of invariable end symbol rotate speed of coldstart,the start time decrease along with the increase of fuel supply quantitylinearly.3. Educe the general way to optimize fuel supply map.4. The essential of intake air heater works is : it increases thetemperature in compress terminal;it increases the evaporation ratio of fueltoward the supplied fuel.5. There is a critical point on the curve of coolant temperature –coldstart time. Coldstart time decreases while coolant temperatureincreases by the left side of the point. Coldstart time increases when coolanttemperature increases by the right side of the point.6. Battery voltage influences coldstart's performance throughinfluencing the drag rotate speed of starter. There is an optimazed lowestdrag rotate speed to any engine duing the course of coldstart. It canconsume lowest power and can pledge engine to be started favourably.7. It can not improve coldstart's performance through heating the fuelsupply pipe.8. There must be three basic conditions to ensure diesel engine start:①The thickness of fuel/air mixture must reach to a certain extent;②The temperature of fuel/air mixture must reach to a certain extent;③The temperature of fuel/air mixture must keep enough time.9. The quantity of HC emission during the course of cold start isdirect ratio to the general quantity of fuel which is consumed before endsymbol rotate speed of coldstart.