5.2. System of injection of fuel
Arrangement of elements of a control system of the Simos engine. Engines of 1.6 l
| 1 - socket For the sensor of Hall (black) 2 - Hall's sensor Under the top cover of a gear belt 3 - sensor of oxygen, 50 N Situation at AT: in a final collector 4 - socket For the oxygen sensor, from the lower party of the car on the right 5 - valve of switching of the inlet pipeline 6 - Simos monitor 7 - control unit of a butterfly valve 8 - sensor of temperature of cooling liquid 9 - measuring instrument of mass of air With the sensor of temperature of the soaked-up air | 10 - accession of weight at RKPP 11 - ignition coils With a step of output power 12 - socket For the detonation sensor 13 - engine speed sensor 14 - socket For the engine speed sensor (black) 15 - detonation sensor 16 - injectors 17 - fuel pressure regulator 18 - adsorber 19 - electromagnetic valve of an adsorber |
Arrangement of elements of a control system of the Motronic engine. Engine of 1.8 l (125 h.p.)
| 1 - the electromagnetic valve for an adsorber 2 - socket For the oxygen sensor (black) 3 - the sensor of temperature of the soaked-up air 4 - control unit of a butterfly valve 5 - Motronic monitor 6 - valve of adjustment of the camshaft 7 - measuring instrument of mass of air 8 - sensor of temperature of cooling liquid 9 - fuel pressure regulator 10 - injectors 11 - ignition coils, output step | 12 - engine speed sensor 13 - sensor of a detonation 2 14 - socket For the sensor of a detonation 2. 15 - sensor of a detonation 1 16 - socket For the engine speed sensor. 17 - socket For the sensor of a detonation 1. 18 - Hall's sensor Instruction: About 8/97 releases the adjustable pipe of an admission with the switching valve in addition is established. |
The electronic control system of the engine regulates amount of the fuel given to cylinders and operates process of ignition. At petrol engines of the AUDI A3 car various control systems are applied.
The electronic control system of the engine provides the following opportunities:
– An exact dosage of fuel in any mode of operation that provides small fuel consumption at the high power.
– Reduction of content of harmful substances in the fulfilled gases thanks to exact dispensing of fuel and use of the catalytic converter.
– Self-diagnostics of a control system of the engine that provides a possibility of bystry troubleshooting. The control system of the engine has memory of malfunctions. If defect in use comes to light, then it is brought in memory of the device. If in the engine there are malfunctions, then there is an opportunity to bring the list of malfunctions allowing to reveal and eliminate defect independently to the printer.
The control unit of the engine represents the microprocessor with high speed. It defines optimum time of injection and amount of injectable fuel. At the same time there is a coordination of operation of the control unit with other systems of the car, for example, to a control system of RKPP or blocking from stealing.
Elements of a control system of the engine keeps the high performance for a long time and practically does not demand service. Replacements when carrying out maintenance demand only the air filter and spark plugs. Serious works on adjustment and repair demand use of difficult diagnostic units. Carrying out them is possible only in conditions HUNDRED.
Adjustment of speed of idling and concentration WITH within carrying out maintenance is not required.
Security measures at work with a control system of the engine / the petrol engine
The fuel system is under pressure! When opening system fuel emission is possible. Therefore the flowed-out fuel needs to be wiped with a rag. Vapors of gasoline are poisonous and is combustible. Use goggles. You monitor good ventilation of a workplace. Have the fire extinguisher.
For an exception of traumatizing people and/or damage of system of injection and ignition it is necessary to observe the following:
– Do not concern and do not disconnect ignition wires at the working engine or at the included starter.
– Disconnect and attach pipelines of system of injection and a wire of ignition, and also electric wires of devices of measurement only at the switched-off ignition.
– It is not necessary to work with electronic system of ignition to people with a warm stimulator.
– When checking a compression the fuel injection is not allowed.
ATTENTION
Remarks on check of a control system of the engine
– For search of malfunctions, first of all, it is necessary to bring indications out of memory of malfunctions and to check vacuum accessions for tightness.
– Reliable functioning of all electric elements of system requires presence of tension not less than 11.5 Century.
– If after search of malfunctions, carrying out repair or check of details are started only for a short time, and then stops, the reason can be that the anticreeping system is blocked. For this purpose it is necessary to interview memory of malfunctions and if necessary to adjust the monitor.
Work of system of injection of the petrol engine
Fuel from the fuel tank is sucked in by an electric gasoline pump and moves via the fuel filter located on a car floor to injectors. The regulator of pressure supports constant pressure in fuel system.
Through electrically the operated injectors fuel a la carte moves in the corresponding inlet pipe just before inlet valves of the engine. The control unit of the engine operates injection duration and by that amount of injectable fuel.
The air which is sucked in in the engine passes the air filter, arrives through a butterfly valve and the soaking-up pipe to inlet valves.
The mass of the soaked-up air defines amount of injectable fuel. The mass of the soaked-up air is measured by the special measuring instrument. In the case of the measuring instrument there is a thin, electrically heated sensitive plate –1– which is cooled with a stream of the air passing through it. For maintenance of constant temperature of a sensitive plate the size of current changes according to the mass of the sucked-in air. The size of current specifies to the control unit engine loading degree and by that regulates amount of injectable fuel.
Arrangement of the film conductor 1 in the measuring instrument of mass of air
Information arriving from various sensors and the teams arriving to executive bodies ensures optimum functioning of the engine in various service conditions. If sensors fail, the control unit switches to the emergency program to exclude damages of the engine and to provide a possibility of the further movement of the car. Failure of sensors not necessarily has to have an adverse effect on operation of the engine. However at the next control of composition of the fulfilled gases it is necessary to consider indications of memory of malfunctions of a control system of the engine.
Sensors and executive mechanisms of engine management
– The butterfly valve is located in the central control unit where information from various sensors is concentrated. The main objective of the control unit is stabilization of the mode of idling at all power setting and conditions of loading. The switch of idling transfers to the control unit information on the provision of idling of a butterfly valve. The control unit via the electric motor opens or closes a butterfly valve, regulating, thus, idling speed.
– The sensor of temperature of cooling liquid and the sensor of temperature of the soaked-up air transfer to the control unit information on the current value of temperatures on the basis of change of value of their electric resistance. At increase of temperature resistance decreases.
– The system of ventilation of the fuel tank consists of an adsorber and the electromagnetic valve. In an adsorber the gasoline vapors which are formed in a tank owing to fuel heating collect. At the working engine of couple of gasoline are sucked away from an adsorber and move in the engine.
– The sensor of oxygen measures the content of oxygen in the fulfilled gases and transmits the corresponding signal to the control unit of the engine.
– The sensor of a detonation serves for definition of the optimum moment of ignition. At malfunctions of ignition supply of fuel to the corresponding cylinder stops.
– Engines of 1.8 l / 125 h.p. with 8/97, engines of 1.6 l have the adjustable inlet pipeline which depending on the speed of the engine changes parameters of the soaking-up path. For this purpose the gate with the pneumatic drive is installed in the inlet pipeline. The long pipeline at low speed thanks to resonant effect provides good filling of cylinders and by that high torque. At the high speed of the engine the inlet pipeline is shortened that provides fuller use of potential of engine capacity.
– Engines of 1.8 l / 125 h.p.: For obtaining optimum power and torque of the engine in the wide range of turns there is a mechanism of regulation of the moment of opening and closing of inlet valves depending on speed. Usually time of opening and closing is defined by a camshaft configuration. For ensuring variable adjustment of cams, camshafts of inlet and final valves are connected with each other by a chain. The hydraulic mechanism of adjustment, depending on engine turns, displaces a point of turn of a chain in a branch of connection of gear wheels of cam-shafts. Thanks to it phases of operation of inlet valves in relation to final are displaced. For increase in torque in the range from low to average turns the adjustment mechanism turns on, and the camshaft of inlet valves opens and closes valves earlier.
Checks of system of injection of fuel – general information
In system of injection of fuel it is independently possible to check only the main electric chains.
If normal operation of the engine is broken, first of all check a condition of electric conducting and sockets. Check a condition of the filtering element of the air filter, and also a state and an interelectrode gap of spark plugs. Check passability of hoses of ventilation of a case of the engine and adjustment of a cable of an accelerator. If the engine still works unstably, check a compression in engine cylinders.
If there is a suspicion for bad work of an injector, clean it.
If the engine still works unstably, check elements of system of ignition.
If malfunction is not eliminated yet, check integrity of fuses and a condition of electric sockets and an electrical wiring. On electric sockets there should not be melted-off contacts, moisture, traces of corrosion, dirt and other damages.
After conducting independent check address on the specialized station "AUDI" for diagnostics of system of injection of fuel on the special equipment.