Basic elements of MPI and MPFI
1 Battery
2 Throttle cable
4 Brake fluid reservoir
5 Expansion tank cap
6 Fuse box
7 Power steering pump reservoir
8 Glass washer reservoir
9 ABS control unit
10 Oil dipstick
11 Roof block cover
13 Oil filler neck
14 Casing
16 Air filter cover
17 Magnetic valve
1 lambda probe relay
2 Electronic control unit
The MPI and MPFI system are multipoint fuel injection systems that share a common control unit with the ignition system. The difference between the systems is that the MPI system is equipped with a two-piece switchable intake manifold, while the MPFI system is equipped with a three-piece non-switchable intake manifold. In addition, the MPFI system does not require an air mass meter.
The principle of operation of the system is that the fuel from the tank is supplied by an electric fuel pump to the annular pipeline, then through individually controlled nozzles it is injected into the intake manifold in front of the intake valves.
The control unit for ignition and injection systems, based on data received from the sensors, regulates the injection time, and therefore the amount of injected fuel.
Control unit sensors
Inductive ignition timing sensor - required when starting the engine to determine the top dead center of the third cylinder. The sensor is installed, as a rule, on the left side of the crankcase.
Coolant temperature sensor - the sensor signal serves as a factor for correcting the moment and time of injection when the engine is not warmed up. The sensor is installed in the coolant line of both cylinder heads.
Hall sensor - the sensor signal is needed when starting the engine in order, along with other sensors, to determine the top dead center of the third cylinder. The sensor is installed on the left cylinder head.
Idle switch and throttle potentiometer - they transmit information to the control unit about the position of the throttle, thereby regulating the moment of shutting off the supply. These elements are installed in a common housing on the throttle block.
Two lambda sensors - they measure the oxygen content in the exhaust gases and inform the control unit about it. The control unit, based on the information received, regulates the ratio of the amount of injected fuel and air. Sensors are installed in the respective exhaust manifolds of each cylinder head.
Idle stabilization valves (not all engines). It regulates the amount of air passing through the throttle at idle. Thus, the specified number of idle revolutions is maintained. A valve is installed on the suction manifold
The intake manifold is designed in such a way that, depending on the engine speed, the intake air can be directed by the valve either along a long path or along a short one. It depends on the torque of the engine.
Exhaust feedback system - it is necessary to reduce the content of harmful substances in the exhaust gases and consists of two valves (mechanical and electrical).
Visitor comments