Electronic control unit
The control unit in the electronic box receives information via a multi-pin connector:
- starter, terminal 50 start and end of the start process;
- throttle potentiometer, its current position;
- Hall sensor of the ignition system for adjusting the engine speed;
- lambda probe in the catalytic converter for measuring the residual oxygen content in the exhaust gases;
- intake air flow meter;
- intake air temperature sensor (only in 110 kW turbo engine);
- coolant temperature sensor in the coolant supply pipe behind the cylinder head;
- knock sensor I on the engine block «detonation» combustion;
- knock sensor II (only in engines with a displacement of 1.8 liters) also on the engine block for precise localization of detonation combustion.
Based on information about the speed and pressure in the intake manifold, the control unit calculates the duration of the opening of the injectors, actuated by electromagnetic means, and, accordingly, the amount of fuel injected. To do this, the control unit is provided with engine characteristics, which are a collection of data on all conceivable engine situations, on the amount of fuel required for each situation and the corresponding ignition timing. The control unit can still vary the characteristics after receiving the so-called corrective signals (e.g. intake air and coolant temperature).
Throttle control unit
Control block (2) ignition / injection system is located in the electronic box on the left rear in the engine compartment (in the so-called humidification tank). in bracket (1) next to the control unit is the location of the height sensor for the turbo engine.
Throttle valve control unit in a turbo engine with a working volume of 1.8 liters: 1 - throttle valve lever; 2 - node for connecting the power supply of the control unit (3) throttle valve; 4 - throttle valve.
The throttle control unit in the 1.6 liter engine is basically identical to the 1.8 liter engine unit, although the mounting position is different. The numbers indicate: 1 - the node for connecting to the power supply; 2 - throttle lever.
In the so-called throttle control unit, three separate units, known as functional units from other injection systems, are combined.
Throttle valve. It is connected by a cable to the pedal in the cabin and doses the flow of fresh air into the engine. The more you press the gas pedal, the more the throttle opens, at full throttle it is fully open.
Throttle Potentiometer. The throttle potentiometer determines the position of the throttle at a given moment in the range from idle (throttle closed) to full throttle (throttle valve fully open). Based on its information, the idle speed stabilization valve, also integrated in the throttle valve, is activated, traction is cut off or the mixture is enriched at full load.
Idle stabilization valve. It lets in metered additional air into the intake ducts behind the throttle valve during the engine warm-up stage, when the servo control is fully turned, when the air conditioning system is running or the automatic transmission stage is set. The increased air flow in the direction of the intake pipe is recognized by the fresh air flow meter and as a result causes an increased fuel supply. Thus, there is a reduction in increased friction in a cold engine or with an increased load on the engine due to the servo pump, air conditioning compressor or automatic transmission, which take power from the engine.
Pressure regulator
pressure regulator (1) fuel is connected to the throttle valve via a vacuum hose (2). It regulates system pressure by increasing or decreasing fuel recirculation.
It is located in the fuel distributor and regulates its pressure on the injectors. For this, information about the level of reduced pressure in the intake manifold is transmitted to it. At idle at closed throttle and very low pressure, it holds a lower pressure. As the pressure drops with increased engine load, the pressure regulator increases the fuel pressure. The fuel pump creates a much higher operating pressure, but by means of a pressure regulator, the return of gasoline to the fuel tank is increased or decreased accordingly.
Injection valves
injection valves (4–7) located in the direction of travel on the left side of the cylinder head in the intake manifold. Further, the numbers indicate: 1 - fuel pressure regulator; 2 - supply gas pipeline; 3 - fuel distribution tube.
In this cutaway model, you can see that each injection valve (3) injects into the suction pipe (4). Fuel is supplied to it from the distribution pipe (1), signals for injection go through the cable connection (2) to the control unit.
With each revolution of the crankshaft, they inject gasoline into the suction channel in front of the intake valve of the corresponding cylinder - the duration is determined by the control unit.
Intake air temperature sensor
With a 110 kW turbo engine, it is located in the air intake hose and can accurately measure the temperature of the air supplied by the turbocharger. Information about the temperature enters the control unit in the form of a resistance value. It is used for optimal fuel dosage. A hot turbocharger, depending on the operating state, strongly heats up the intake air.
Coolant temperature sensor
The coolant temperature is used to control several injection functions: air/fuel mixture enrichment during cold start, post-launch enrichment (over the entire temperature range), when enriched during accelerations and cutting off thrust. Information about the temperature of the coolant is also transmitted to the control unit in the form of a resistance value. It calculates the correct injection time, which in a warm engine is between 2 and 8 ms. This value can rise by almost 70% when temperatures drop to arctic levels of -25°C.
Fresh air flow meter
There is an electrically conductive plate in the intake air stream, which is electrically heated. Depending on the amount of air taken in, its flow changes, which cools the plate more or less. A change in temperature causes a change in the electrical resistance of the conductor. This measured value is used by the control unit.
At the rear right in the engine compartment of naturally aspirated engines with a displacement of 1.6 and 1.8 liters is a fresh air flow meter (1), flanged to the air filter housing. Numeric «2» connector is shown. On the 1.8 liter turbo engine, the fresh air flow meter is located inside the air filter housing.
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