Hyundai Accent

Repair and car operation

6.11. A control system of engine MFI

Placing of elements of control system MFI

1 – a measuring instrument of the expense of air "OBD"; 2 – the gauge of temperature of air arriving in the engine; 3 – a measuring instrument of the expense of air, except "OBD"; 4 – the gauge топливовоздушной mixes, except "OBD"; 5 – the gauge of temperature of a cooling liquid; 6 – the gauge of position throttle заслонки; 7 – the gauge of position of a camshaft; 8 – the gauge of an angle of rotation of a cranked shaft; 9 – the warmed gauge of oxygen; 10 – fuel atomizers; 11 – the modulator of frequency of idling; 12 – the gauge of speed of the car;

13 – the detonation gauge; 14 – the switch of ranges of a transmission; 15 – the ignition lock; 16 – the block of engine management ЕСМ; 17 – the relay of a central air of air; 18 – the electromagnetic valve of clearing of the canister with the activated coal; 19 – the main relay MFI; 20 – ignition coils; 21 – the fuel pump; 22 – the acceleration gauge; 23 – a diagnostic socket.

Management of fuel system is carried out by the block of engine management ЕСМ (Engine Control Module). Block ESM spends adjustment of a corner of an advancing of ignition, defines quantity of fuel submitted to the engine, operates system of decrease in toxicity of the fulfilled gases and frequency of rotation of a cranked shaft of the engine idling, and also coupling of the compressor of the conditioner etc. Block ESM changes power setting depending on changing operational modes on the basis of signals from various switches and gauges.

For example, block ESM regulates a corner of an advancing of ignition on the basis of signals of gauges which react to frequency of rotation of a cranked shaft, temperature of a cooling liquid, position throttle заслонки, the transfer included at present, speed of the car etc.

Block ESM regulates frequency of rotation of a cranked shaft of idling on the basis of signals of gauges which react to position throttle заслонки, the speed of the car included at present transfer etc.

The gauge of a measuring instrument of the expense of air "OBD" (MAF – Mass Airflow Sensor)

The measuring instrument of the expense of air provides the most direct method to measure engine loading as it measures quantity of air arriving in the engine. Air stream arrives in the engine through a measuring instrument with нагретым and cold the wire elements forming a part of the bridge scheme. The current passing through нагретый a wire element, maintains its constant temperature at constant level, which above, than temperature of air arriving in the engine. The weight of air is defined on a current strength necessary for maintenance of temperature of a wire element. The more a stream of air and, naturally, its cooling, the more size of the signal submitted on block ESM.

The gauge of temperature of air arriving in the engine "OBD" (IAT – intake air temperature)

The gauge of temperature of air arriving in the engine represents термистор which resistance changes depending on temperature. Block ESM considers a signal of the gauge and corrects width of the impulse submitted on atomizers therefore the quantity of the fuel submitted to cylinders of the engine changes, and also changes a corner of an advancing of ignition.

Gauge check

PERFORMANCE ORDER

1. Measure pressure between contacts 1 and 3 sockets of the gauge. Temperature Target pressure 0°C 3,3–3,7 IN 20°C 2,4–2,8 IN 40°C 1,6–2,0 IN 80°C 0,5–0,9 IN 2. If target pressure of the gauge differs from demanded, replace the gauge.

The gauge of absolute pressure in an inlet collector, except "OBD" (MAF – Manifold Absolute Pressure)

The gauge of absolute pressure in an inlet collector represents the sensitive variable resistor. It measures pressure in an inlet collector which changes depending on operational modes of the engine and is transformed to pressure. The gauge also is used for measurement of atmospheric pressure at start of the engine and provides power setting at different heights above sea level. On the basis of the information from the gauge the engine management block regulates quantity of fuel submitted to the engine, and also changes a corner of an advancing of ignition.

Check

PERFORMANCE ORDER

1. Measure pressure between contacts 1 and 4 sockets of the gauge. Target pressure at the included ignition and the idle engine: 4–5 In Target pressure on frequency of idling: 0,5–2,0 In 2. If target pressure of the gauge differs from demanded, replace the gauge.

The gauge of temperature of air arriving in the engine (IAT – intake air temperature)

The gauge of temperature of air arriving in the engine represents термистор which resistance changes depending on temperature. Block ESM considers a signal of the gauge and corrects width of the impulse submitted on atomizers therefore the quantity of the fuel submitted to cylinders of the engine changes, and also changes a corner of an advancing of ignition.

Check

PERFORMANCE ORDER

1. Measure resistance between contacts 1 and 2 sockets of the gauge. Temperature Resistance 0°C 4,5–7,5 Ohm 20°C 2,0–3,0 Ohm 40°C 0,7–1,6 Ohm 80°C 0,2–0,4 Ohm 2. If resistance of the gauge differs from demanded, replace the gauge.

The gauge of temperature of a cooling liquid (ECT – Engine Coolant temperature)

The gauge of temperature of a cooling liquid supervises temperature of a cooling liquid and on the basis of a signal of the gauge block ESM calculates width of the impulse submitted on atomizers therefore the quantity of the fuel submitted to cylinders of the engine changes, and also changes a corner of an advancing of ignition.

On the cold engine block ESM works in a mode of an open loop therefore in engine cylinders moves richer топливновоздушная a mix and frequency of rotation of idling increases. It proceeds before achievement by the engine of normal working temperature.

Removal

PERFORMANCE ORDER

1. Remove the gauge from the engine. 2. Heating up a vessel with water and the gauge located in it, check up its resistance. Temperature Resistance –30°C 22,22–31,78 clod –10°C 8,16–10,74 clod 0°C 5,18–6,60 clod 20°C 2,27–2,73 clod 60°C 1,059–1,281 clod 40°C 0,538–0,650 clod 80°C 0,298–0,322 clod 90°C 0,219–0,243 clod 3. If resistance of the gauge differs from demanded, replace the gauge.

Installation

PERFORMANCE ORDER

1. Put on a carving of the gauge hermetic LOCTITE 962T. 2. Screw the gauge in the block of cylinders and tighten its demanded moment. The inhaling moment: 15–20 Н•м 3. Connect to the gauge an electric socket.

The gauge of position throttle заслонки (TP – Throttle Position)


The gauge of position throttle заслонки hands over the information on which basis block ESM defines when throttle заслонка it is closed, is completely open or is in intermediate positions. The gauge is rigidly connected to shaft throttle заслонки. Depending on position throttle заслонки resistance of the gauge changes. For a food of the gauge from block ESM on it pressure 5 V.Vyhodnoe pressure of the gauge moves changes from 0,25 In at the minimum opening throttle заслонки to 4,7 In at full opening throttle заслонки.

Check

PERFORMANCE ORDER

1. Disconnect a socket from the gauge of position throttle заслонки. 2. Measure resistance between contacts 1 and 2 sockets of the gauge. Resistance: 0,7–3,0 clod 3. Connect an ohmmeter to contacts 1 and 3 sockets of the gauge. 4. Slowly open throttle заслонку and be convinced that resistance of the gauge smoothly changes proportionally to opening throttle заслонки. 5. If resistance of the gauge differs from demanded or changes in steps, replace the gauge. The inhaling moment: 1,5–2,5 Н•м

The gauge of position of a camshaft (CMP – Camshaft Position Sensor)


The gauge of position of a camshaft develops impulses on which basis block ESM identifies the first cylinder and time of opening of an atomizer.

The gauge of an angle of rotation of a cranked shaft (CKP – Crankshaft Position Sensor)


The gauge of an angle of rotation of a cranked shaft hands over to block ESM the information on position of a cranked shaft. On the basis of the information of a target signal of this gauge and a signal of the gauge of position of a camshaft block ESM defines a corner of an advancing of ignition and the cylinder to which it is necessary to submit fuel. In the absence of target signals of the gauge the engine will not be started.

Check

PERFORMANCE ORDER

1. Disconnect a socket from the gauge of an angle of rotation of a cranked shaft 2. Measure resistance between contacts 1 and 2 sockets of the gauge. Resistance: 0,486–0,594 clod at 20°С 3. If resistance of the gauge differs from demanded, replace the gauge. Backlash between a rotor and the gauge of an angle of rotation of a cranked shaft: 0,5–1,0 mm The inhaling moment: 9–11 Н•м

The oxygen gauge


Depending on the oxygen maintenance in the fulfilled gases the oxygen gauge induces pressure from 0 to 1 V.Na the basis of this data the engine management block changes time of opening of atomizers and a fuel parity in топливновоздушной mixes. That there was a full combustion of a gas mixture and in the fulfilled gases there were no harmful substances, on 14,7 weight parts of air 1 part of fuel should have.

The oxygen gauge is equipped by a heater which maintains temperature of the gauge in a certain interval at engine work on all operational modes. Maintenance of certain temperature of the gauge allows system to get into gear and work faster in an idling mode.

Check

PERFORMANCE ORDER

The prevention Before check warm up the engine until the temperature of a cooling liquid will not be equal 80–95°C. By the exact digital voltmeter measure target pressure of the gauge. If target pressure of the gauge differs from demanded, replace the gauge. The inhaling moment: 50–60 Н•м

Fuel atomizers


Fuel atomizers on the basis of signals from block ESM inject fuel into engine cylinders. The quantity of submitted fuel depends on time of opening of atomizers, i.e. from width of an impulse of pressure submitted on an atomizer winding.

Check

PERFORMANCE ORDER

1. At engine work idling a stethoscope or a hand finger check up work of atomizers on presence of clicks. 2. If clicks are absent, check up reliability of connection of sockets to atomizers and target pressure of the block of management. 3. Disconnect a socket from a fuel atomizer and measure resistance between socket contacts. Resistance: 15,9± 0,35 Ohm 4. Connect a socket to a fuel atomizer.

The detonation gauge


The detonation gauge reacts to high-frequency fluctuations of the block of cylinders and transforms them to the electric signals which size increases at detonation increase. On the basis of these signals block ESM displaces the moment of ignition towards delay therefore the detonation is eliminated.

Fuel pipelines and hoses

Fuel pipelines and hoses provide transfer of fuel from a fuel tank to a fuel highway and atomizers and return superfluous fuel in a tank. The fuel pipelines fixed on the bottom of the car, probably restriction of a stream of fuel is necessary to examine periodically on absence of dents and deformation, as at the expense of narrowing of their passes.
Fuel pipelines and hoses also provide transfer of steams of fuel from a fuel tank to the canister with the activated coal where they gather at the switched off engine. After start-up of the engine and warming up to working temperature the engine management block opens the electromagnetic valve, and steams of fuel from the canister arrive in the engine and are burnt.