Contents: Fuel supply system ⤓ Distributed injection system ⤓ Fuel injection control (fuel supply) ⤓ Additional air regulation (idle…⤓ Adjusting the ignition timing angle ⤓
Fuel supply system
In order to improve passive safety and increase the volume of the luggage compartment, a fuel tank made of steel is installed under the floor of the rear seats of the car. The fuel tank is equipped with a valve block, which includes a fuel shut-off valve to prevent fuel from leaking out of the tank in the event of an accident (car rollover) and a two-way valve for regulating the pressure inside the tank. For ease of operation and maintenance, a high-pressure plastic fuel hose with quick-release couplings is used between the fuel pump assembly and the fuel filter assembly on vehicles with gasoline engines.
Distributed injection system
The distributed fuel injection system consists of sensors that record the engine status, an electronic engine control unit (engine-ECU), performing control functions based on signals from sensors and actuators operating on commands from the control unit. The control unit controls fuel injection, idle speed and ignition timing. In addition, the control unit has a number of diagnostic operating modes that make it easier to troubleshoot.
Fuel injection control (fuel supply)
The moment the injector begins to open and the duration of its open state are set in such a way that the engine receives a fuel-air mixture of optimal composition, corresponding to the continuously changing operating conditions of the engine. The injector is installed on the inlet pipe of each cylinder. Fuel is supplied by the fuel pump from the fuel tank to the fuel manifold under pressure, the value of which is maintained by the pressure regulator. In the fuel manifold, fuel is distributed to each injector under a certain pressure. Under normal conditions, fuel is injected once every two crankshaft revolutions for each cylinder. The firing order of the cylinders is 1-2-3-4-5-6. This mode is called sequential fuel injection. The electronic control unit ensures enrichment of the fuel-air mixture during engine warm-up, as well as during operation under maximum load, implementing control without feedback on the mixture composition ("open-loop"). If the engine is warmed up or operates in partial modes, the control unit ensures maintenance of stoichiometric (theoretically necessary for complete combustion of fuel) composition of the fuel-air mixture, implementing feedback control ("closed-loop") based on the mixture composition using signals from the oxygen sensor. This ensures maximum efficiency of the three-way catalytic converter.
Additional air regulation (idle speed control)
The electronic engine control unit maintains optimal idle speed depending on external conditions and engine load by regulating the amount of air entering the engine through the bypass channel, bypassing the throttle valve. The engine control unit controls the idle speed control (ISC) servo, ensuring that the set speed is maintained depending on the coolant temperature and the air conditioning load. In addition, when the air conditioner is switched on and off in idle mode, the idle speed control (ISC) stepper motor doses the amount of additional air in such a way as to eliminate fluctuations in the crankshaft speed.
Adjusting the ignition timing angle
The power transistor connected to the primary circuit of the ignition coil closes and opens the circuit.
In this way, optimal control of the ignition timing angle is achieved in accordance with the engine operating mode. The electronic engine control unit determines the optimum ignition timing angle depending on the engine crankshaft speed, the volumetric air flow entering the engine, the coolant temperature and atmospheric pressure.
[The text of the article was obtained from the website MITSUBISHIMAN.ru]