6.2. Systems of injection of fuel (EFI) and engine management - model of 4.2 l of release after 1992.
General information
On an accompanying illustration the type of a motive compartment of model of 4.2 l of EFI with an arrangement of various components of feed and control systems the engine is presented.
Since October, 1994 manufacturers refused use of the electromagnetic valve of the regulator of pressure.
The control system of the engine in this manual is called an electronic control system of ignition of fuel (ECCS). The system exercises control at the same time of ignition and injection of fuel.
The central ECCS component is the control unit (ECU) which is the microprocessor. ECU operates installation of a corner of an advancing of ignition and amount of injectable fuel on the basis of the signals received by it from various sensors. At registration of changes of load of the engine, speed, issues to the speed of the movement of the car, temperature of cooling liquid, the provision of a butterfly valve, the choice of transfer, temperature of the soaked-up air and composition of the fulfilled ECU gases commands for the corresponding correction of a corner of an advancing of ignition and time of opening of injectors of fuel for the purpose of receiving the maximum return from the engine in the current conditions.
At registration of the repeating abnormal signal of ECU remembers a contour of a source of a signal and writes down it in the memory block in the form of a digital code that significantly facilitates the procedure of diagnostics of malfunctions of system. At detection of malfunction of the sensor of an angle of rotation of the distributor or global internal refusal in ECU influencing overall performance of the engine there is an inclusion of a control lamp "Check the engine" for dashboards along with which ECU includes system of emergency functioning that allows to continue operation of the car with limited opportunities of the engine before elimination of a cause of failure. Reading of codes of malfunctions from memory of ECU in a workshop of dealer office of the manufacturing company of the car will facilitate diagnostics of causes of failure.
The distributor, powerful key of the output cascade, the coil of ignition and connecting electrical wiring are a part of high-energy system of ignition.
The distributor performs double function. First, it carries out giving of secondary tension of the coil on spark plugs. Secondly, the distributor delivers to ECU информациею about turns of the engine and position of pistons. This information is removed by the sensor of an angle of rotation located in the distributor.
As the control system of the engine is responsible for installation of a corner of an advancing of ignition, the distributor is not equipped neither vacuum, nor centrifugal with proofreaders of the moment of ignition.
The powerful key of the output cascade is fixed near the ignition coil. Also performs function of interruption of primary contour, joining at the command of ECU. At the same time in a secondary contour high voltage is induced.
The coil of ignition has the special design meeting the special requirements of electronic system of ignition and has to be replaced only on similar to.
Power supply of the engine is provided by electronic system of multiposition injection of fuel. The system provides injection of fuel in a stream of the soaked-up air in inlet ports of a head of cylinders. Further air-fuel mix moves in combustion chambers via inlet valves.
Supply of fuel to injectors is provided by the high-pressure pump of submersible type fixed in the fuel tank. For the purpose of suppression of the pulsations of fuel caused by operation of injectors and own functioning, the pump is equipped with a special damper.
Pressure in a power supply system is supported at the level of 235 ÷ 294 kPa, depending on pressure in the pipeline. Control of pressure of fuel is exercised by the special regulator which is built in to the fuel highway. When the engine does not work, fuel on the site between injectors and a gasoline pump remains under pressure thanks to installation in the pump of the unilateral valve.
The amount of injectable fuel is defined by time of opening of injectors. Duration of an interval of opening of injectors is defined by ECU on the basis of the data obtained from the sensor of an angle of rotation of the distributor and the measuring instrument of an air stream. The basic duration of injection then can be corrected on the basis of information of the sensor of temperature of cooling liquid (CTS), sensors switches of a butterfly valve and permission of start, the sensor of speed of the movement of the car, the provision of a key in the lock of ignition and data of the l-probe for the purpose of receiving from the engine of the maximum return in specific conditions and the current mode of operation.
The air regulator provides increase in turns of idling of the engine in the course of its warming up at the expense of a perepuskaniye of an air stream bypassing a butterfly valve. The bimetallic plate which is curved at warming up by electric current operates operation of the air regulator. Being curved, the bimetallic spring rotates a disk in the air regulator that leads to gradual reduction of a stream of air up to its full overshoot.
The block of adjustment of air of idling (IAA) installed in a back part of the delivery camera of an air path operates turns of idling of the engine. The block is equipped with the screw of adjustment of turns, the valve of additional air and the device of compensation of turns of bystry idling (FICD).
The AAS valve provides supply of additional air bypassing a butterfly valve, thereby supporting idling turns at increase in loads of the engine. The FICD device operates similar to the AAS valve, but serves especially for compensation of the increase of loading connected with turning on of the conditioner of air.
The case of a throttle is located on the delivery camera of an air path and operates amount of the air which is soaked up in the engine depending on position of the accelerator pedal.
Efficiency of action of a control system of the engine depends on the accuracy of information arriving on ECU on the volume of the operated air stream from the measuring instrument of an air stream. Thus, special importance is gained by purity, quality of a state and reliability of fastening of all air, fuel and electric connections.