6.2. Power supply system of petrol engines
Principles of functioning of a control system of the petrol engine
Since the power supply system is a part of the control system uniting also systems of ignition and decrease in toxicity of fulfilled gases (OG), to consider them separately it is not obviously possible. The description of a control system by the engine below is provided.
Components of electronic control by the engine in ME-Motronic system
Fuel is sucked in from a fuel tank by the electric fuel pump and moves via the fuel filter to the fuel distributive highway. The regulator of pressure provides pressure maintenance in fuel system at level of 3.5 atm.
Through electrooperated injectors fuel impulsno is injected into the inlet ports located directly ahead of inlet valves of the engine. The control unit determines by the engine (ECM) the optimum moments of ignition and injection, and also amount of injected fuel in coordination with other systems of the car. The high voltage for an iskroobrazovaniye on a signal of ECM is generated by the coils of ignition established over spark plugs.
The sensor of provision of a cranked shaft (CKP) gives to the control unit information on number of turns of a cranked shaft and its exact situation. This information is used for definition of the moments of injection and ignition. The CKP sensor is located on the back party of the engine and works at a basis of effect of the Hall, scanning a teeth of the rotor established on cranked shaft.
The sensor of provision of a camshaft (CMP) is located at an end face of a head of cylinders and works similar to the CKP sensor, scanning a gear rotor on the end of an inlet camshaft. The CMP sensor together with the CKP sensor is used for definition of VMT of the piston of the first cylinder, dynamic adjustment of phases GRM (means Ý/m the valve and a regulator of phases of inlet valves), selective regulation of a detonation in cylinders and for definition of sequence of injection.
The air necessary for formation of a working mix, is sucked in by the engine via the air filter and arrives through a butterfly valve and the inlet pipeline to inlet valves. The amount of soaked-up air is regulated by a butterfly valve with э / a drive operated on signals from the sensor of the provision of a pedal of gas. Thanks to electronic control the mass consumption of air in the inlet pipeline can be established irrespective of the provision of a pedal of gas, and on single turns the butterfly valve opens on a corner necessary for installation of demanded frequency of rotation of a cranked shaft. The mass of soaked-up air decides by the MAF sensor on the built-in sensor of temperature of soaked-up air (IAT).
The sensor of a detonation (KS) will screw sideways in the block of cylinders and interferes with emergence of shock combustion of fuel. Thanks to it the moment of ignition keeps on detonation border that provides the best use of energy of fuel and, thereby, decrease in its expense.
Information from other sensors and the operating tension arriving to executive bodies, provides optimum operation of the engine in any situation. If some sensors fail, the control unit is switched in a mode of the emergency program to exclude possible damage of the engine and to provide further movement of the car. In emergency operation injectors work at the same time, 2 times for a running cycle.
The system of ventilation of a fuel tank consists of an absorber паров gasoline and Ý/m the valve. In an absorber fuel pairs which are forming in a tank as a result of heating of fuel concentrate. In engine operating time fuel pairs are pumped over from an absorber and participate in formation of a working mix.
Decrease in toxicity of OG is carried out by means of the 3-functional catalytic converter and a lambda probes (before and after the catalytic converter).
Also the system of ventilation of karterny gases (PCV) is applied to elimination of leakages of not burned down hydrocarbons in the atmosphere. Gases and pairs of oil which are forming in a case, get to the inlet pipeline (at the expense of a pressure difference – in a case it higher) and burn down in cylinders together with fuel.
In order that numerous electronic control units could exchange with each other data, these blocks are incorporated the high-speed tire of data transmission of CAN. The tire CAN consists of two lines that allows to reduce number of electroconducting. Each control unit can transfer and accept at the same time the data, however each concrete block reads out from the tire CAN only data necessary for it.