The principle of operation of the fuel injection system
The fuel pump takes fuel from the fuel tank and delivers it to the accumulator, in which the fuel is at a pressure of 1.5-2.4 kg / cm2 when the engine is stopped. Further, the fuel is supplied under pressure through the filter to the fuel dispenser-distributor.
The pressure disk of the air flow meter fixed on the movable lever, which is installed between the air filter and the throttle valve, deviates depending on the air depression in the engine. The displacement of the pressure disk of the air flow meter is transmitted to the distribution plunger of the fuel dispenser, thereby determining the amount of fuel supplied. The fuel quantity distributor, depending on the position of the pressure plate of the air flow meter, supplies the required amount of fuel to the engine cylinders through the injectors, ensuring the optimal composition of the air-fuel mixture. The fuel dispenser and air flow meter form a mixture regulator.
The pilot pressure regulator reduces pressure on the control plunger during engine warm-up. Reducing the control pressure at the same air flow leads to an increase in the fuel supply and, consequently, to an enrichment of the combustible mixture.
An additional air supply valve installed in the air duct, made parallel to the throttle valve, brings additional air to the engine during cold start and engine warm-up, which leads to an increase in the engine idle speed.
To facilitate starting a cold engine, an electromagnetic starting nozzle is provided, the opening time of which varies depending on the temperature of the coolant by a thermal time switch.
Air filter
Air filter with replaceable dry filter element.
Fuel electric pump
The fuel electric pump is located in the fuel tank in a submerged position.
Fuel supply for 30 s at a voltage of 12 V at the terminals, see3:
- pump with pin connector: 750;
- pump with threaded connector: 900.
Productivity at voltage on outputs of 12 V, l/min 1,8.
Consumed current at a voltage of 12 V at the terminals, no more than, A; 6.5.
Fuel storage
The fuel accumulator is installed under the bottom of the body next to the fuel tank on the right.
Fuel filter
The fuel filter is located in the engine compartment.
Pilot pressure regulator
Brand and catalog number: Bosch 0 438 140 073.
Resistance of the heating winding of the bimetallic spring of the regulator, Ohm:
- YZ engine: 16-22;
- engine DZ: 20-26.
Fuel dispenser
Brand and catalog number: Bosch 0 438 100 082.
Injection nozzles
Brand and catalog number: Bosch 0 437 502 015.
Volume of injected fuel, ml:
- at idle: 3.0;
- at full load: 8.0.
Injection start pressure, kg/cm2: 2.5-3.5
The maximum allowable pressure difference between the injection nozzles, kg/cm2: 0.6.
Starting nozzle
Duration of fuel injection, s
- at +35°С: 0;
- at 0°C: 6.
Air flow meter
Brand and catalog number: Bosch 0 438 120 128.
Thermal time relay
Brand and catalog number: Bosch 0 280 130 228.
Idle air control valve
The fuel injection system of the DZ engine includes an idle control valve, which is controlled by a special electronic unit
The valve turns on at a crankshaft speed of 700 rpm and turns off at 1050 rpm.
Adjustment Data
The frequency of rotation of the crankshaft at idle, rpm:
- YZ engine with contact ignition system or contactless ignition system and digital idle speed stabilizer: 900-1000;
- YZ engine with contactless ignition system and digital stabilizer of the spiked stroke: 750-850;
- DZ engine: 850-950.
Carbon monoxide content (SO) in exhaust gases at idle, %:
- YZ engine: 1.0-2.0;
- DZ engine: 0.5-1.5.
Fuel pressure in the system, kg/cm2:
- YZ engine: 4.5-5.2;
- DZ engine: 4.7-5.4.
Control pressure on a warm engine, kg/cm2: 3.4-3.8.
Pilot pressure on a cold engine at an ambient temperature of 20°C:
- YZ engine (with the block disconnected from the control pressure regulator): 1,35-1,65;
- DZ engine (with shoes disconnected from the control pressure regulator and the secondary air valve): 1,0-1,4.
Residual fuel pressure in the system, kg/cm2:
- 10 minutes after stopping the engine: 1.8;
- 20 minutes after stopping the engine: 1.6.
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