Direct Petrol Injection System with Bosch Motronic MED 7 - Volkspage

More documents

Recommendations

Info

Engine management Intake manifold pressure sender G71, This sender is attached to the intake manifold upper section. It measures the pressure inside the intake manifold and sends a corresponding signal to the engine control unit. Signal utilisation The engine control unit utilises this signal, as well as the signals from the air-mass flow meter and the intake air temperature sender, to compute the exact exhaust gas recirculation rate. The intake manifold pressure sender is also used for load sensing during engine start-up since the signals from the air mass meter are too inaccurate due to intake pulsation. 253_061 This is how it works Intake manifold pressure is measured via a silicon crystal membrane. Located on this membrane are strain gauges whose resistance is altered when the membrane is deformed. The reference vacuum is used for pressure comparison purposes. Depending on intake manifold pressure, the membrane undergoes deformation, causing a change of resistance which results in different signal voltages. The engine control unit uses this signal voltage to determine the pressure inside the intake manifold. Low vacuum = high output voltage High vacuum = low output voltage Semiconductors 253_141 Reference vacuum Silicon crystal membrane 253_142 28
This is how the exhaust gas recirculation rate is determined Using the air-mass flow meter, the engine control unit measures the intake fresh air mass and calculates from this the corresponding intake manifold pressure. If exhaust gas is fed in via the exhaust gas recirculation system, then the fresh air mass is increased by the exhaust gas intake and the intake manifold pressure rises. The intake manifold pressure sender measures this pressure and sends a corresponding voltage signal to the engine control unit. The total quantity (fresh air+exhaust gas) is determined from this signal. The engine control unit subtracts the fresh air mass from this total quantity and thus obtains the exhaust gas quantity. The advantage is that the exhaust gas recirculation rate can be raised closer to the operating limit. Air-mass flow meter G70 intake air temperature sender G42 Sensor for pressure sender G71 <strong>Motronic</strong> control unit J220 EGR valve N18 Exhaust gas recirculation potentiometer G212 253_134 Signal failure strategies If the intake manifold pressure sender fails, then the exhaust gas quantity is calculated by the engine control unit and the exhaust gas recirculation rate is reduced in relation to the map. 29
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: Air-mass flow meter G70 and intake
Page 31 and 32: Fuel system The fuel system is divi
Page 33 and 34: This is how it works The fuel flows
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

Create successful ePaper yourself

Delete template?

Save as template?