Direct Petrol Injection System with Bosch Motronic MED 7 - Volkspage

More documents

Recommendations

Info

Engine management Fuel pressure sender (G247) is located on the intake manifold lower section and is screwed into the fuel rail. it measures the fuel pressure in the fuel rail. Signal utilisation The engine control unit utilises the signal from the fuel pressure sender for map-dependent regulation of the fuel pressure in the high-pressure fuel system. Fuel pressure sender (G247) 253_046 This is how it works Fuel flows out from the fuel rail into the fuel pressure sender. low Fuel pressures high - The steel membrane is only slightly deformed at low fuel pressure, with the result that the resistance in the strain gauges is high and the signal voltage is low. - The steel membrane is heavily deformed at high fuel pressure, with the result that the resistance in the strain gauges is low and the signal voltage is high. Evaluation electronics Steel membrane with strain gauges Pressure connection - fuel rail 253_091 The signal voltage is amplified by the electronics and sent to the engine control unit. The fuel pressure is regulated by the fuel pressure regulating valve. Electrical connection Evaluation electronics Signal failure strategies If the signal from the intake manifold pressure sender fails, the fuel pressure regulating valve is activated by the engine control unit at a fixed value. Steel membrane with strain gauges Pressure connection - fuel rail 253_029 34
The fuel pressure regulating valve (N276) is located on the lower section of the intake manifold and is screwed in place between the fuel rail and the return line leading to the fuel tank. Task The task of the fuel pressure regulating valve is to adjust the fuel pressure in the fuel rail irrespective of the injection quantity and pump delivery rate. Fuel pressure regulating valve (N276) Fuel return line 253_129 This is how it works Electrical connection pressure spring If deviations from the setpoint pressure are detected, the fuel pressure regulating valve is activated by a pulse-width modulated signal from the engine control unit. As a result of this, a magnetic field is induced in the magnetic coil and the valve with the valve ball lifts off the valve seat. In this way, the flow cross-section to the return line is changed depending on signal size, thus altering the discharge rate and regulating the fuel pressure. Solenoid Magnet armature Fuel return line 253_033 Failure strategies Fuel rail inlet with inlet strainer Valve seat Drain hole Fuel return line The regulating valve is closed in de-energized state. This ensures that sufficient fuel pressure is always present. To protect the components against excessively high pressures, a springoperated mechanical pressure limiting device is built into the fuel pressure regulating valve. It opens at a fuel pressure of 120 bar. Valve with valve ball 35
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 and 32: Fuel system The fuel system is divi
Page 33: This is how it works The fuel flows
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

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?