5.2.2. General information
Prevention
The fuel system is under pressure a long time after switching off of the engine. At any separation of fuel-supply lines it is necessary to take off previously pressure in fuel system.
The power supply system consists of the fuel tank installed under a back part of the car, the electric fuel pump shipped in a tank, the fuel filter, the fuel highway and returnable fuel hoses. The fuel pump gives fuel to the fuel highway which also performs functions of the tank for fuel nozzles. The fuel filter installed between the fuel highway and the fuel pump makes purification of fuel.
System of injection of Multec fuel
Prevention
There are no regulir manual idling turns as turns of idling are regulated by a control system of the ECU engine.
The system of injection of fuel consists of a fuel supply system, system of measurement of a stream of air and system электричес whom engine management. The system of injection of fuel with one nozzle installed in the throttle case, in fact, replaces the carburetor. Such systems are called injection in the case of a throttle (TBi) or the central injection of fuel (CFI) or single-point injection.
The fuel supply system consists of the fuel tank with the electric fuel pump shipped in it, the fuel filter, a fuel nozzle, the regulator of pressure of the fuel installed in the throttle case and also the hoses and tubes connecting system elements. At inclusion of ignition or only at the working engine on the X16 SZ models the electronic control device (ECU) via the relay of the fuel pump and the fuse 11 gives tension to the fuel pump. The pump gives fuel via the fuel filter to a fuel nozzle. Fuel pressure size in the fuel highway is defined by the regulator which at increase in pressure returns excess fuel in the fuel tank.
The system of measurement of a stream of air has the block of adjustment of temperature of the air coming to the engine, the air filter and elements which are in the case. The fuel nozzle which injects fuel into a back part of a butterfly valve, and a potentiometer of provision of a butterfly valve is installed in the case of a throttle. The potentiometer of a butterfly valve is rigidly connected with an axis of the gate and transfers to the ECU block information concerning the provision of a butterfly valve at the moment of time. The step engine operated by the ECU block operates amount of the air given to the engine and is intended for support of turns of idling at the required level.
The electric control system of the engine consists of the ECU block together with the following sensors:
– the potentiometer of a butterfly valve reports to the ECU block the provision of opening or closing of a butterfly valve,– the sensor of temperature of cooling liquid reports to the ECU block engine temperature,
– the sensor of oxygen reports to the ECU block the content of oxygen in exhaust gases,
– the detonation sensor installed in the block of cylinders is used for detection of the beginning of a detonation or early ignition,
– the sensor of provision of a bent shaft reports to the ECU block turns of the engine and the provision of a bent shaft,
– the sensor of absolute pressure in a collector reports to the ECU block depression in an inlet collector.
All information from sensors is analyzed by the ECU block and on this basis the corresponding corner of an advancing of ignition and composition of fuel mix is defined. The block operates a fuel nozzle, changing the impulse width, i.e. an interval of time when the nozzle is open to provide richer or poorer fuel mix.
The ECU block also controls idling turns. For this purpose there is a step engine operating the provision of a butterfly valve.
If there is a mistake in any of the data obtained from sensors, the ECU block enters a way of the doubler. In this case the ECU block ignores the wrong signal of the sensor and accepts previously programmed value which allows the engine to continue work, though with smaller efficiency. If ECU is included into a way of the doubler, then the lamp of the alarm system on a combination of devices will light up and damage will be written down in memory of ECU. After that it is necessary to carry out full test of a control system of the engine, using special electronic диагностичес a cue the test bench which just turns on in the diagnostic socket of system.
System of injection of Motronic fuel
The system of injection of Motronic fuel is a joint system of ignition and injection of fuel.
The fuel pump shipped in the fuel tank gives fuel from a tank to the fuel highway via the fuel filter. Fuel pressure in system is run by pressure regulator. The regulator allows excess fuel to come back to the fuel tank at excess of pressure in fuel system. The fuel highway is the tank for four fuel nozzles which make injection of fuel to inlet canals of cylinders. On the SOHC engine fuel nozzles receive only one boost opening them at the same time, once for one turn of a bent shaft. On DOHC engines the posledova telny system of injection at which nozzles inject fuel of a nezavisa мо from each other is used. The ECU block operates a fuel nozzle, changing the impulse width, i.e. an interval of time when the nozzle is open to provide richer or poorer fuel mix. ·
On SOHC engines air passes through the air filter, the measuring instrument of a stream of air and a butterfly valve to inlet channels of cylinders. In the case of the measuring instrument of a stream of air there is a gate which when passing an air stream deviates. The corner of a deviation of the gate serves as an air stream measure. From a potentiometer on a gate axis the signals corresponding to position of the gate come to the control unit. The control unit regulates time and amount of injectable fuel according to the measured amount of air and speed of the engine. The longer the nozzle is open, the more fuel is injected. For adjustment of turns of idling there is a screw potentsiomt ра on the measuring instrument of a stream of air which changes the basic tension going to the ECU Motronic block.
On DOHC engines the air coming to the engine passes through the air filter, the air stream measuring instrument with a heated wire and through the case of an on-off throttle to inlet channels of cylinders. The sensor of a stream of air represents the wire which is energized. The sensor sends constantly changing tension signal corresponding to the mass of the air passing in the engine. Two butterfly valves are installed in the case of a throttle. For adjustment of turns of idling the potentiometer screw installed on the measuring instrument of a stream of air and changing the basic tension going to the ECU Motronic block is used.
The sensor of provision of a butterfly valve defines the provision of a butterfly valve, and on some models and extent of opening of a butterfly valve. Information from the sensor of provision of a butterfly valve is used for reduction of supply of fuel when braking the engine therefore fuel is saved and the content of harmful substances in exhaust gases decreases.
Turns of idling are run by the valve with an opening of variable section which changes amount of the air given to a round of a butterfly valve. The valve is run by the ECU block and adjustment of turns of idling is impossible.
Additional sensors transfer information to the ECU block about temperature of cooling liquid, temperature of the air coming to the engine, and on models with the catalyst – about the content of oxygen in exhaust gases.
The fuel filter is located in the giving fuel-supply line and purifies the fuel arriving to nozzles.
The relay of the fuel pump is run by the ECU block which blocks supply of fuel to the fuel pump at switching off of ignition.
Later system of injection of M2.8 Motronic fuel is similar устанав ливавшейся to system of injection of M2.5 Motronic fuel except for the next moments earlier:
– the tape measuring instrument of a stream of air in exchange is used earlier having used шегося the conductor energized. The principle of its action is similar to earlier used. Constant temperature of a tape is maintained by electric current which changes depending on the mass of the passing air. Current which needs to be given for maintenance of constant temperature of a tape is proportional to the mass of a stream of air;– the sensor of temperature of the air coming to the engine is installed in a hose between the measuring instrument of a stream of air and the air filter and intended for measurement of temperature of the air coming to the engine. On the basis of a signal of this sensor and other sensors the ECU block defines time of opening of fuel nozzles;
– on system of injection Motronic M2.8 the potentiometer of provision of a butterfly valve instead of earlier used switch of provision of a butterfly valve is used.
System of injection of Simtec fuel
In system of injection of Simtec fuel the bigger quantity an electron of ny knots and sensors is used.
In the control unit the control system of electronic ignition which is called microprocessor system with inductive management of ignition (MSTS-i) is installed. In system of ignition there is no mechanical distributor of ignition. The control unit is located behind the decorative panel in deepening for the passenger's legs about a door rack.
Instead of one coil of ignition the dual coil of ignition which is run by the control unit is used.
The sensor of provision of a bent shaft is intended for definition of the top dead point, a corner of provision of a bent shaft and turns of the engine. On the basis of signals of this sensor the control unit defines a corner of an advancing of ignition and the moment of injection of fuel.
The tape measuring instrument of mass of a stream of air determines the mass of air, a postup yushchy in the engine and on the basis of this information the control unit defines time of opening of fuel nozzles.
The sensor of temperature of the air (NTC) coming to the engine is installed in the inlet air duct between the air filter and the measuring instrument of a stream of air.
On the basis of signals of the sensor of a detonation the corner of an advancing of ignition is regulated and at the same time is absent bypass the bridge in an octane proofreader.
Besides, in system of injection of Simtec fuel the system of repeated combustion of exhaust gases (EGR) and system of compulsory forcing of air which reduces amount of not burned down fuel in exhaust gases is installed.
Prevention
Gasoline extremely fire - is also explosive therefore it is necessary to show care during the work on any part of fuel system.
Works on fuel system need to be performed in well aired room for what it is possible to open all windows and doors for draft creation.
During the work on fuel system do not use naked flame, electric welding and tools during the work with which sparks can be formed. Check that in close proximity to a workplace there is a charged fire extinguisher.
For protection of eyes against hit of fuel in them use points. At hit of fuel on skin wash out this place a plentiful amount of water.
Capacity in which there was a fuel contains vapors of fuel and is potentially explosive.
During the work with fuel system observe purity as the dirt which got to canals of fuel system can block them that will break normal operation of the engine.