Direct Petrol Injection System with Bosch Motronic MED 7 - Volkspage

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Engine management High-pressure fuel pump is screwed to the camshaft housing. This three-cylinder radial piston pump is driven by the inlet camshaft. Pressure fluctuation in the fuel rail is kept to a minimum by the three pump elements which are arranged at 120° apart. The task of the high-pressure fuel pump is to develop fuel pressure up to 100 bar in the highpressure fuel system. 253_058 Pump element with Pump piston Slide shoe Lifting ring Eccentric cam Drive The input shaft of the high-pressure fuel pump is driven by the inlet camshaft. An eccentric cam on which a lifting ring is mounted is located on the input shaft. When the input shaft rotates, the eccentric cam, in conjunction with the lifting ring, provides for upward and downward motion of the pump piston. - Fuel is drawn out of the low pressure fuel system during the downward movement of the pump piston. - Fuel is pumped into the fuel rail during the upward movement of the pump piston. Pump cylinder Inlet valve Eccentric cam with lifting ring Inlet camshaft Drive shaft 253_030 Exhaust valve To fuel rail From low pressure fuel system 253_128 32
This is how it works The fuel flows from the low pressure fuel system into the high-pressure fuel pump where it flows through the hollow pump piston to the intake valve. Suction lift The downward motion of the pump piston produces an increase in volume inside the pump cylinder, causing the pressure to drop. As soon as the pressure in the hollow pump piston is greater than the pressure in the pump cylinder, the intake valve opens and additional fuel flows into the cylinder. Fuel High pressure Fuel Normal pressure Exhaust valve closed Pump cylinder Intake valve open Pump piston (hollow) to fuel rail from low pressure fuel system 253_096 Delivery head At the start of the upward movement of the pump piston, the pressure in the pump cylinder rises and the intake valve closes. If the pressure in the pump cylinder is greater than the pressure in the fuel rail, the exhaust valve opens and fuel is pumped to the fuel rail. Exhaust valve open Pump cylinder Intake valve closed to fuel rail from low pressure fuel system 253_026 33
Page 1 and 2: Service. Self-Study Programme 253 D
Page 3 and 4: Table of Contents Introduction . .
Page 5 and 6: Why has Volkswagen waited until now
Page 7 and 8: Homogeneous operation at high exhau
Page 9 and 10: Combustion process The term "combus
Page 11 and 12: Injection cycle Fuel is injected du
Page 13 and 14: Homogeneous lean charge mode This i
Page 15 and 16: Mixture formation process By inject
Page 17 and 18: Motronic control unit J220 Fuel pum
Page 19 and 20: Torque-based engine management syst
Page 21 and 22: Intake system In comparison with th
Page 23 and 24: This is how it works The driver inp
Page 25 and 26: Intake manifold flap actuated In st
Page 27 and 28: Air-mass flow meter G70 and intake
Page 29 and 30: This is how the exhaust gas recircu
Page 31: Fuel system The fuel system is divi
Page 35 and 36: The fuel pressure regulating valve
Page 37 and 38: This is how it works Inlet with fin
Page 39 and 40: Activated charcoal canister system
Page 41 and 42: Exhaust system This was adapted to
Page 43 and 44: Broadband lambda probe (G39) The br
Page 45 and 46: Exhaust gas temperature sender (G23
Page 47 and 48: NOx sensor control unit (J583) This
Page 49 and 50: Function of the NOx sender The func
Page 51 and 52: Sulphur regeneration is a technical
Page 53 and 54: Variable valve timing Inner exhaust
Page 55 and 56: Positive terminal GND Input signal
Page 57 and 58: Notes 57 Solutions to questions on
Page 59 and 60: 5. What is the signal from the inta

Direct Petrol Injection System with Bosch Motronic MED 7 - Volkspage

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