Direct Petrol Injection System with Bosch Motronic MED 7 - Volkspage

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Fundamentals Operating modes In addition to "stratified charge mode" and "homogeneous charge mode", the 1.6l - 81kW FSI engine has a third operating mode: homogeneous lean charge mode. This operating mode offers a further reduction in fuel consumption compared to lambda=1 mode <strong>with</strong> exhaust gas recirculation. The engine control unit selects the operating mode depending on torque, power, exhaust gas and safety requirements. Stratified charge mode The engine runs in stratified charge mode up to the medium engine load and speed range. Through mixture stratification in the combustion chamber, the engine can be operated at a total lambda of approx. 1.6 to 3. - A highly ignitable mixture forms around the spark plugs at the centre of the combustion chamber. - This mixture is enveloped by an outer layer which ideally comprises fresh air and recirculated exhaust gas. Homogeneous lean charge mode In the transition zone between stratified charge mode and homogeneous charge mode, the engine runs in homogeneous lean charge mode. The lean mixture is distributed homogeneously (evenly) throughout the combustion chamber. The air/fuel ratio is approximately lambda 1.55. Homogeneous charge mode At higher engines loads and speeds, the engine runs in homogeneous charge mode. The air-fuel ratio in this operating mode is lambda=1. Engine load Homogeneous charge mode Homogeneous lean charge mode Stratified charge mode 8 253_085 Engine speed
Combustion process The term "combustion process" describes the way in which the air/fuel mixture forms and energy is converted inside the combustion chamber. In homogeneous charge mode and homogeneous lean charge mode, the fuel is injected into the cylinder during the intake stroke and mixes homogeneously <strong>with</strong> the intake air. In stratified charge mode, The air-fuel mixture is positioned in the area of the spark plugs by a wall/air guided tumble combustion process. The injector is positioned in such a way that the fuel is injected into the fuel recess (wall-guided configuration) and guided from here to the spark plugs. The intake manifold flap change-over mechanism and the flow recess produce tumble air motion inside the cylinder. This airflow (airguided configuration) assists in transporting the fuel to the spark plugs. Mixture formation takes place on the way to the spark plugs. Intake manifold flap changeover mechanism High-pressure Injector red=jet inclination angle 20° blue=jet angle 70° Fuel recess (wall-guided) Flow recess (air-guided) 253_039 9
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: Homogeneous operation at high exhau
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 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
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Direct Petrol Injection System with Bosch Motronic MED 7 - Volkspage

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