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1、L o g Company LogoCompany LogoSection 5. Low Emission VehicleSection 4. Vehicle LightingSection 3. EOBD Fuel System Monitoring; Misfire Monitoring.Monitors for non-continuously monitoring: Exhaust Gas Recirculation Monitor, EGR; Oxygen Sensor System Monitor; Second Aid System Monitor; Evaporative Sy
2、stem Monitor, EVAP; Catalyst Monitoring; Heated Catalyst Monitoring; Positive Crankcase Ventilation System Monitoring, PCV; Oxygen sensor heater monitoring; Air Conditioning System Refrigerant Monitor.Evaporative/ivpreitiv/ 蒸发的蒸发的Catalyst/ 催化剂催化剂 Crankcase/krk,keis/ 曲轴箱曲轴箱vent hole Ventilation Refri
3、gerant/rifridrnt/ 制冷剂制冷剂L o g Company LogoCompany Logo3.2. Monitored system and components Fuel system monitoringShort-term fuel trim (Lambda control) occurs when the pre- catalyst Lambda sensor voltage has an immediate impact on injection duration during closed loop operation. For example, the ECU
4、might find it necessary to increase injector duration to compensate for the affects of an air leak.Long-term fuel trim occurs while the vehicle is being driven within a specific load and RPM window.The short-term fuel trim diagnostics will run when: The engine is running; Coolant temperature is abov
5、e 140F; The fuel system is operation in closed loop.Short-term Long-term a. trim / 修剪修剪 修正修正 Fahrenheit / 华氏温度华氏温度L o g Company LogoCompany Logo3.3. Monitored system and components Misfire detectionAn on board diagnostic system must be able to detect and react to two different misfire situations. Th
6、e difference lies in the severity of the fault. If the problem is minor it reacts accordingly, a severe problem demands a more rapid and forceful response.The two types of misfire are: Catalyst damaging misfire, a level of misfire so severe that there is a danger of damaging the catalyst. Emission r
7、elated misfire, will result in the vehicle failing an inspection/maintenance-test or which causes emissions to exceed the federal test procedure standards by more than 50%.L o g Company LogoCompany Logo3.4. Monitored system and components EGR system monitoringThis function monitors the EGR-value and
8、 the EGR-gas flow. The most common problem is carbon build-up.EGR stands for Exhaust Gas Recirculation, meaning that you return some of the exhaust gas from the exhaust manifold into the input of the engine. The recirculated exhaust gases are aspirated into cylinders together with the air/fuel mixtu
9、re and occupies some part of the volume of the combustion chamber.These gases dont take part in the combustion process but they cause the combustion to take place at a lower temperature than would be the case without EGR. Because oxides of nitrogen are normally produced at high combustion temperatur
10、es the production of these components is therefore reduced.carbon / 碳碳 EGR = Exhaust Gas Recirculation exhaust manifold 排气歧管排气歧管 aspirate /spreit/ 吸入吸入 oxides / 氧化物氧化物 nitrogen / 氮氮L o g Company LogoCompany Logo3.5. Monitored system and components Oxygen sensor monitoringThis is perhaps the most imp
11、ortant monitor. Its the heart of the fuel system.It tells the vehicle ECU how much fuel has been burnt. The signal from the sensor is also the feedback to the engines adaptive fuel control system.L o g Company LogoCompany Logo3.6. Monitored system and components Evaporative System MonitoringModern c
12、ars have closed fuel systems. The reason for this is to stop fuel vapor reaching the environment. The fuel tank is the biggest source of this kind of vaporization.When the engine is shut off, the vapors are collected in a special container called a canister.The EVAP-valve is opened when the engine h
13、as reached optimum combustion. The vapor is sucked into the engine and burnt.engine shut offcanister / sucked / gas leakage connections, seals , hosesThe monitoring system controls, among other things, the pressure in the fuel tank, in order to stop the tank exploding on a hot day. It also monitors
14、gas leakage at connections, seals and hoses.L o g Company LogoCompany Logo3.7. Monitored system and components Catalyst monitoringRegulations require the on-board diagnostic system to monitor the catalyst once per trip.The catalyst is deemed to be malfunction when hydrocarbon (HC) output is 1.5 times more than FTP standards.malfunction / HC - hydrocarbon /L o g Company LogoCompany Logo3.7.1. Monitored system and components 3-way catalytic converterThree-way catalytic converters contain one or more precious metals-palladium, platinum or rhodium-used to catalyze the unburned hydrocarbo
