Scheme of the injection system with exhaust gas recirculation
1. High pressure fuel pump; 6. Retainer of the membrane mechanism of the vacuum ignition timing regulator; 60. Exhaust gas recirculation valve; 62b. Throttle with filter; 65. Vacuum vacuum valve; 67. Vacuum pump; 99. Hydro valve; 100. Hydraulic valve of the membrane mechanism of the vacuum ignition timing regulator; 105. Inlet gas pipeline; 105a. Hydraulic valve body; 105b. The connecting pipeline of inlet air 110. An exhaust manifold; 128a. Thermostat (closes at 30°C); 136. Flywheel; 224. Accelerator pedal; Q11/8. Dual temperature sensor (coolant/ preheating device); L3. Speed sensor; N14. Control relay; N22. Refrigeration compressor shutdown control device; N37. ARF control device; S27/6. microswitch; Y27. Switching valve ARF; Y28. Hydraulic valve changeover valve
2.0L engine: Injectors are powered by a high-pressure Bosch in-line fuel pump with a mechanical regulator and built-in anti-shock switching circuit (KARA), which greatly reduces torsional vibrations in the drive phase.
Control device for anti-shock switching circuit (N8/2) same as control device for flue gas recirculation (AGR) located in the engine compartment on the right behind the front wall of the cabin under the cover for control devices.
2.2/2.5L Engine: Electronic Diesel Control (EDC = Electronic Diesel Control) contributes to a more precise matching of the injected amount of fuel with the corresponding mode of operation of the car, due to which, in comparison with mechanical systems, significant improvements are achieved in almost all modes of operation.
2.2l engine: Mercedes introduces for the first time an electronically controlled fuel injection system with a high-pressure distributor fuel pump (EPIC = Electronic Programmable Injection Control). Unlike the in-line high pressure fuel pump, which has a plunger pair for each cylinder, the high pressure distribution pump has only two booster pump pistons rotating in the rotor, and the regulation of the injected amount of fuel, as well as the peak distribution (distribution of the beginning of the peak load with increasing speed in the direction "early injection") carried out by means of a piston hydraulically controlled by means of electromagnetic valves.
The valves are actuated by an electronic control device. The type and duration of the control pulses depends on the factors registered by the sensing elements and processed in the control device using sorted universal characteristics. These include intake manifold pressure, engine speed, intake air, coolant and fuel temperatures, among others.
The position of the accelerator pedal is determined by the driver and the switch (R25/2), the signals of which are precisely entered into the electronic control device, where they are processed and controlled. The setting device is located in the engine compartment on the left behind the front wall of the cab and is connected to the accelerator pedal by means of a gas cable.
The engine is stopped by a solenoid valve. If its power supply itself is interrupted by the ignition switch and anti-theft devices, or due to system errors in the control electronics, the valve shuts off the fuel supply to the booster pump pistons. If the shut-off valve malfunctions, the control device sets the fuel injection quantity system to "0" (zero feed) and, due to this, stops the engine. At the same time, the malfunction is stored in the control device, and the EDC flashes on the instrument panel - a control lamp.
Additionally with actuation of solenoid valves in the distribution pump for flue gas recirculation (AGR) in combination with intake air throttling system (ALD) is regulated by means of an engine control valve, and the AGR valve and throttle valve are respectively actuated by pneumatic adjusters.
2.5L engine: The 5-cylinder engine is also equipped with an electronically controlled fuel injection system in combination with an in-line high-pressure fuel pump (M/RE).
Instead of a mechanical speed controller (2.0L engine) the solenoid actuator takes over the regulation of the amount of fuel injected according to the position of the accelerator pedal. The accelerator pedal position is determined by the engine control unit, as with the 2.2 liter engine.
In addition to controlling the amount of fuel injected, the electronic engine management also takes over the control of the exhaust gas recirculation (AGR) combined with intake air throttling (ALD) depending on engine speed, load and engine temperature.
The engine is stopped by an electro-hydraulic switch (Y1/1), located on the side of the high pressure fuel pump. The fuel temperature sensor is located in the same housing (contacts 1/2).
fuel pump (13) located on the outside of the in-line fuel injector pump. The coarse filter is located in the main filter housing, and heated fuel flows out from there, due to which it, despite the low outside temperature, has better fluidity.