5.14.1. Features of a design
Elements of the following systems are a part of a power supply system:
– the fuel supply system including the fuel tank, the fuel pump with the built-in regulator of pressure of fuel, pipelines, a fuel stage with nozzles and also the fuel filter;
– the system of air supply including the air filter airbringing a sleeve, throttle knot, the idling regulator;
– the system of catching of vapors of fuel including an adsorber, the adsorber purge valve, a separator of vapors of fuel and connecting pipelines.
Functional purpose of a fuel supply system — ensuring giving of necessary amount of fuel in the engine on all operating modes. The engine is equipped with an electronic control system with the distributed fuel injection. In system of the distributed injection of fuel of function of a smeseobrazovaniye and dispensing of supply of fuel-air mix in cylinders of the engine are divided: nozzles make the dosed injection of fuel in the inlet pipeline, and the amount of air, necessary at every moment of operation of the engine, moves the system consisting of throttle knot and the regulator of idling. Such way of management gives the chance to provide optimum composition of gas mixture at each concrete moment of operation of the engine that allows to receive the maximum power at minimum possible fuel consumption and low toxicity of the fulfilled gases. The electronic control unit the engine which is continuously controlling by means of the corresponding sensors engine loading, speed of the movement of the car, a thermal condition of the engine, an optimality of process of combustion in engine cylinders operates system of injection of fuel and system of ignition.
Feature of system of the phased injection of fuel is synchronism of operation of nozzles according to gas distribution phases (the control unit of the engine obtains information from the phase sensor). The control unit includes nozzles consistently, but not in pairs, as in systems of asynchronous injection. Each nozzle joins through 720 ° turn of a bent shaft. However on the modes of start-up and dynamic power setting the asynchronous method of supply of fuel without synchronization with rotation of a bent shaft is used.
The main sensor for ensuring optimum process of combustion is the sensor of concentration of oxygen in the fulfilled gases (lambda probe). It is established in a reception pipe of system of production of the fulfilled gases and together with the control unit of the engine and nozzles forms a contour of management of composition of the fuel-air mix given to the engine (fig. 5.11). The control unit of the engine determines amount of not burned down oxygen in the fulfilled gases by sensor signals and respectively estimates an optimality of composition of the fuel-air mix coming to engine cylinders in each timepoint.
Fig. 5.11. Scheme of a contour of management of composition of fuel-air mix: 1 – the sensor of concentration of oxygen in the fulfilled gases (lambda probe); 2 – final collector; 3 – engine; 4 – nozzle; 5 – control unit of the engine; 6 – catalytic converter of the fulfilled gases
Having recorded the structure deviation from optimum 1:14 (fuel/air) ensuring the most effective functioning of catalytic converter of the fulfilled gases the control unit by means of nozzles changes composition of mix. as the sensor of concentration of oxygen is switched on in a chain of feedback of the control unit of the engine, the contour of management of composition of fuel-air mix is closed.
The fuel tank is made of plastic, installed under a body floor and attached to a body floor by three arms.
The bulk pipe is made for a single whole with the fuel tank. In order that vapors of fuel did not get to the atmosphere, the tank is connected by the pipeline to an adsorber. In a flange opening in the top part of a tank the electric fuel pump with the fuel level sensor is installed. From the pump fuel moves in the fuel filter installed under a body floor in its back part on the right. Via the threefold union at the exit from the fuel filter fuel is distributed on two highways. On one highway it moves in the fuel stage fixed on the inlet pipeline. On the second highway excess fuel via pressure regulator installed in the fuel module comes back in a tank.
Fuel-supply lines and hoses of a power supply system are made on special technology of maslobenzostoyky materials.
Application of the fuel-supply lines differing on a design from recommended by manufacturer, can lead to power supply system failure, and in certain cases even to the fire.
The module of the fuel pump includes the electric pump, the fuel pressure regulator...
... and sensor of the index of level of fuel.
The module of the fuel pump provides supply of fuel and is installed in the fuel tank that reduces probability of formation of steam traffic jams as fuel moves under pressure, but not due to depression. Besides, greasing and cooling of details of the fuel pump improves.
The submersible fuel pump, bladed type, with the electric drive. The pump of a non-demountable design, is not subject to repair, at failure it should be replaced.
The regulator of pressure of fuel is installed in the module of the fuel pump and intended for maintenance of constant pressure of fuel in a fuel stage. The regulator is connected in the beginning of the giving highway (at once after the fuel filter) and represents perepuskny the valve with a spring which effort is strictly calibrated.
The fuel filter of thin cleaning — full-line, is fixed in an arm under a body floor in its back part on the right. The filter is non-demountable, consists of the steel case and the paper filtering element.
The fuel stage of 2 (fig. 5.12) represents a hollow detail with openings for nozzles 3 with the union for accession of a fuel-supply line of high pressure and fastening arms to the inlet pipeline. Nozzles are condensed in openings of a stage and in nests of the inlet pipeline with rubber rings 4 and fixed by spring clamps 1. The stage assembled with nozzles is inserted by shafts of nozzles into openings of the inlet pipeline and fixed by two bolts.
Fig. 5.12. Fuel stage: 1 – nozzle clamp; 2 – stage; 3 – nozzle; 4 – sealing ring of a nozzle
Nozzles (fig. 5.13) are attached to a stage from which to them fuel moves, and the sprays enter openings of the inlet pipeline. In openings of a stage and the inlet pipeline of a nozzle are condensed with rings 1 and 3. The nozzle is intended for the dosed injection of fuel in the cylinder of the engine and represents the high-precision electromechanical valve. Fuel under pressure arrives from a stage on channels in the nozzle case to the locking valve.
Fig. 5.13. Nozzle of system of injection of fuel: 1 – top sealing ring; 2 – shtekerny conclusions of a winding of an electromagnet; 3 – lower sealing ring
The spring draws in a needle of the locking valve to a conical opening of a plate of a spray, holding the valve in a closed position. Tension given from the control unit of the engine through shtekerny conclusions 2 on a nozzle electromagnet winding creates in it the magnetic field involving the core together with a needle of the locking valve in an electromagnet. The conical ring opening in a plate of a spray opens, and fuel is injected via the spray case diffuser into the inlet channel of a head of the block of cylinders and further into the engine cylinder. After the termination of receipt of an electric impulse the spring returns the core and a needle of the locking valve in an initial state — the valve is locked. The amount of the fuel injected by a nozzle depends on duration of an electric impulse.
The air filter is installed in the right forward part of a motor compartment on an engine mudguard.
The filter is connected by the rubber corrugated airbringing sleeve to throttle knot.
The filtering element of the air filter paper, flat, with a big area of the filtering surface.
The throttle knot represents the control device and serves for change of amount of the main air given to inlet system of the engine. It is established on an entrance flange of the inlet pipeline. The formed rubber sleeve fixed by a collar and connecting throttle knot to the air filter is put on an entrance branch pipe of throttle knot.
Fig. 5.14. Throttle knot: 1 – case of throttle knot; 2 – idling regulator; 3 – sensor of provision of a butterfly valve; 4 – butterfly valve; 5 – sector of the drive of a butterfly valve
In the case 1 (fig. 5.14) of throttle knot the opening for a supply of additional air to the idling regulator is executed.
The butterfly valve turning on an axis 4 is installed in the case 1. On one end of an axis the sensor 3 provisions of a butterfly valve of a control system of the engine, on another — sector 5 to which the cable of the drive of a butterfly valve is attached is installed. On the case 1 the regulator of idling 2 dosing an air stream at the closed butterfly valve is fixed.
In use the throttle knot does not demand service and adjustment, watch only a condition of rubber consolidations to avoid an air suction.
The regulator of idling supports the set frequency of rotation of a bent shaft of the engine at completely closed butterfly valve during its start-up, warming up and at change of loading during turning on of the service equipment.
The regulator changes amount of the additional air given to inlet system passing a butterfly valve, and represents the step electric motor attached by two screws to a flange of the case of throttle knot.
The control unit of the engine, having processed the entering signals from sensors, determines the necessary frequency of rotation of a bent shaft of the engine and respectively position of the valve of the regulator. Changing position of the valve of the regulator, the control unit changes the size of section of the bypass canal in throttle knot. The control unit compensates these the significant increase or reduction of amount of the given air caused by its suction through untight inlet system, or, on the contrary, a contamination of the air filter.
Turning on of additional units causes the increase in load of the engine which is followed by decrease in frequency of rotation of idling and change of depression in an inlet pipe that is also compensated by the control unit by means of the idling regulator.