6.2. Power supply system of petrol engines
General information
All models considered in the present manual are equipped with electronic system of the distributed injection of fuel (SFI). Due to use in a control system of the latest technology solutions of SFI provides optimization of configuration of air-fuel mix under any service conditions of the engine.
Fuel is in a power supply system under constant pressure and through injectors is injected into inlet ports of each of engine cylinders. The dosage of supply of fuel is carried out by management of time of opening of electromagnetic valves of injectors according to the amount of the air forced in the engine determined by specific conditions of functioning. Duration of opening of injectors is defined by parameters of the electric impulses formed by the module of management (ECM) that allows to carry out very exact dosage of components of gas mixture.
ECM determines the required duration of time of opening of injectors on the basis of the analysis of the data on amount of the air which is soaked up in the engine which are continuously arriving from information sensors - the termoanemometrichesky sensor of measurement of mass of air (MAF), the current turns of the engine - the sensor of provision of a bent shaft (CKP), and the provision of butterfly valves - TPS.
Besides the listed functions the system of the distributed injection of fuel exercises also control of toxicity of the fulfilled gases, optimization of a ratio an expense fuel/efficiency of return of the engine, and also provides adequate starting parameters and warming up of the engine in cold weather, proceeding from data on temperatures of cooling liquid (ECT sensor) and the soaked-up air (IAT sensor).
System of air supply
Inlet air path
The inlet air path consists of an air inlet, two rezonatorny cameras, assembly of the air cleaner and the air duct connecting it to the throttle case. The first resonator is located above the air cleaner on a stream, by means of a by-pass hose is connected to a back part of an air inlet and effectively promotes decrease in level of the noise background arising at absorption of air in the engine. The second rezonatorny camera is connected to an air duct of an inlet air path directly ahead of the throttle case.
Structure of the inlet air highway of the petrol engine
The air banished via the air cleaner comes to the throttle case, from where, in the quantity determined by the provision of butterfly valves (TPS sensor), on the inlet pipeline moves to inlet ports of cylinders of the engine where it mixes up with the fuel injected through injectors, forming gas mixture. Stability of turns of idling is provided at the expense of a perepuskaniye of a part of air mass bypassing the throttle case directly in the inlet pipeline. Control of amount of the bypassed air is exercised by ECM by means of management of functioning of the special perepuskny valve of stabilization of turns of idling (IAC).
The sensor of temperature of the soaked-up air (IAT)
The IAT sensor is installed on assembly of the air cleaner and serves for measurement of temperature of the air which is soaked up in the engine. The thermistor which resistance in inverse proportion to temperature of a sensitive element is the basis for a design of the sensor. The parameters traced by the sensor will be transformed to electric signals and transferred to ECM exercising control of configuration of air-fuel mix and also the moments of injection and ignition.
Sensor of measurement of mass of air (MAF)
The Termoanemometrichesky MAF sensor is installed in the inlet air highway directly behind the air cleaner and acts as the source of information delivering to ECM data on amount of the air which is soaked up in the engine. On the basis of the analysis of information of ECM arriving from the sensor carries out configuration of air-fuel mix.
Throttle case
The gates placed in the case of a throttle are operated from the accelerator pedal according to which position, to a greater or lesser extent block throttle openings through passage that allows to regulate an expense of the air engine coming to combustion chambers. On single turns when the accelerator pedal is completely released, gates are blocked almost completely by a throttle and bulk of air (more than a half) comes to the inlet pipeline via the special electromagnetic valve of stabilization of turns of idling (IAC) bypassing the throttle case. Use of the IAC valve allows to exercise also control of stability of turns of idling regardless of changes of the current load of the engine (for example, at turning on of the conditioner of air or other power-intensive consumers).
Throttle case design
Sensor of provision of butterfly valves (TPS)
TPS is established on the case of a throttle and is mechanically connected to an axis of butterfly valves. The sensor develops and sends ECM the alarm tension which size is directly proportional to extent of opening of gates. To the closed and opened provisions of gates there correspond accurately certain values of tension.
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ECM is allocated with the mental abilities allowing it to compensate inevitable times ые changes of performance data of the sensor at their binding to the provision of a butterfly valve. |
Electromagnetic valve of stabilization of turns of idling (IAC)
The IAC valve is switched on in an inlet air path ahead of the case of a throttle and exercises control of the size of a consumption of the air bypassed bypassing the last during the operation of the engine on single turns. The valve works on ECM signals, allowing the last to support turns of idling of the engine at the set level.
IAC valve design
Fuel supply system
General information
The submersible fuel pump placed in a gasoline tank provides supply of fuel under pressure to each of injectors of the fuel highway. Gasoline moves from the pump to injectors on a fuel path with the filter of thin cleaning which is switched on in it. The special regulator supports fuel pressure in the highway at the set optimum level. Through injectors fuel in necessary quantity is injected directly into combustion chambers of each of engine cylinders where mixes up with air and forms gas mixture. The amount of fuel and the moment of injection are calculated by the module of management. Excess of fuel on the returnable line comes back to the fuel tank.
Scheme of the organization of a fuel supply system
Fuel tank
The fuel tank of 60 l made of stamped steel is installed under the car, right in front of the back bridge under assembly of a back seat.
The tank is equipped with the filter protecting it from blows by stones and fastens under the car bottom by means of five bolts.
The configuration of working volume of a tank is chosen so that the toplivozabornik of a gasoline pump remained in the shipped situation at any level of filling of a tank, even during sharp maneuvering.
The special unilateral valve preventing penetration of fuel from the working volume of a tank back in a mouth at the movement on off road terrain and sharp maneuvering is built in a jellied mouth of a tank.
Remember that correct (before operation of a graggers of a ratchet) tightening of a cover of a jellied mouth is a guarantee of maintenance of the required excessive pressure in a fuel path.
Do not forget to exhaust the car on a platform from time to time and to attentively examine the fuel tank and lines brought to it regarding identification of mechanical damages.
Fuel pump
The fuel pump is united in uniform assembly with the fuel reserve sensor. The pump has a rotor design and is placed in the fuel tank that allows in an essential measure to reduce the level of the noise background made by it during the work.
Control of functioning of the fuel pump is exercised by ECM. At development activation of the relay of the fuel pump then the electric motor begins to rotate happens the module of management of the corresponding team, setting a rotor of pump assembly in motion. The fuel which is sucked in via the mesh filter of a toplivozabornik on connecting lines comes to the fuel highway and under a pressure moves on injectors. The pumped pressure in a fuel path is supported at the constant level by means of the special regulator. For the purpose of prevention of pressure drop of fuel at shutdown of a gasoline pump pump assembly switched on the special locking valve.
Excess fuel on the returnable line is taken away back in the fuel tank.
Fuel pressure regulator
The regulator of pressure is installed since the end of the line of supply of fuel brought to injectors and consists of two cameras divided by a diaphragm: fuel and spring. The fuel chamber is connected to the line of supply of fuel, spring - to the inlet pipeline. At increase in depth of depression in the inlet pipeline procrastination of a diaphragm leads to opening of the returnable line brought to a fuel chamber of the regulator, - as a result pressure in the fuel highway decreases. Decrease in depth of depression in the pipeline leads to push-up of a diaphragm a spring and to increase in the giving pressure. The described mechanism allows to support a difference between pressure of injection and depression in the inlet pipeline at the constant level making 290 kPa.
Fuel injectors
In system of the distributed injection injectors with the top supply of fuel are used. The scheme of connection of injectors provides cooling them with a fuel stream. Injectors of such design differ in the compact sizes, high thermal stability, the lowered noise background and simplicity in service.
Duration of opening of the electromagnetic needle valve of an injector is defined by length of the developed ECM of the operating impulse. In view of the fact that the injector nozzle section, size of opening of the valve and pressure of supply of fuel are supported by constants, the amount of the fuel injected into the combustion chamber is defined only by duration of time of the opening corresponding to length of the operating impulse.
Fuel reserve sensor
The sensor is united in uniform assembly with the fuel pump and consists of the float fixed on the lever and a potentiometer.
Change of level of fuel is monitored by a potentiometer under the provision of a float, the corresponding indication is output to the measuring instrument which is built in in a combination of devices.
Connecting lines of a fuel path
Supply of fuel from a gasoline pump to the fuel highway and its return to the fuel tank is carried out on metal by tubes and to hoses of lines of giving and return of fuel. Lines by means of clamps fasten to the car bottom. Also have to be checked for existence of mechanical damages regularly.
Besides the giving and returnable fuel pipes it is also necessary to carry to number of connecting lines of a path of a power supply system lines of withdrawal of fuel evaporations on which vapors of fuel accumulating in the fuel tank during the parking are taken away in the special coal adsorber which is located in a motive compartment. When squeezing the accelerator pedal after warming up of the engine up to the normal working temperature at the command of ECM the adsorber purge with a conclusion of the fuel which accumulated in it in the inlet pipeline with its subsequent burning in a normal running cycle of the engine is carried out.
Filter of thin cleaning
The filter of thin cleaning is switched on in structure of the line of supply of fuel.
The case of the fuel filter is capable to maintain rather high temperature, vibration and shock loadings. In the case the paper filtering element providing purification of the fuel given to the fuel highway of the foreign particles which are not caught by a grid of a toplivozabornik of a gasoline pump and capable to put injectors out of action is enclosed.
Recommendations about economy of fuel consumption
Style of driving of the car has significant effect on fuel consumption. The recommendations given below will allow the owner to achieve economy of fuel consumption when receiving adequate return from the engine.
- Try to avoid long warmings up of the engine, - begin the movement at once as soon as turns are stabilized;
- At a car stop for a while more for 40 seconds you suppress the engine;
- Always try to move on the highest transfer, avoiding sharp dispersals;
- On distant trips whenever possible try to move with a uniform speed. Avoid the movement at excessively high speeds. Drive the car circumspectly. Without need you do not brake;
- You transport the car excessive freight. If the top luggage carrier is not used, remove it from a roof;
- Regularly check pressure of a rating of tires, without allowing its excessive decrease.