The central control and regulator unit for engine management, which together with the EATS ensures that the engine runs under all operating conditions in as economical a manner as possible, with low pollutant and low-noise, is the engine management (MCM) control unit (A4).
It calculates the optimal start of injection as well as the injection quantity required for combustion according to the operating condition of the engine and the torque request of the drive control (CPC) control unit (A3).
The engine management (MCM) control unit (A4) also ensures that the fuel is injected at the correct time and in the correct quantity into the cylinder by means of the precise electrical actuation of the fuel injector for cylinder 1 (Y608), fuel injector for cylinder 2 (Y609), fuel injector for cylinder 3 (Y610), fuel injector for cylinder 4 (Y611), fuel injector for cylinder 5 (Y612) and fuel injector for cylinder 6 (Y613).
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Input signals, shown on engine 471.9 |
A4 | Engine management control unit (MCM) | B611 | Temperature sensor downstream of air filter (only for engine version Euro VI Standard) | |
B600 | Crankshaft position sensor | B617 | Charge air temperature sensor in charge air distributor | |
B601 | Camshaft position sensor | B621 | Exhaust gas recirculation (AGR) differential pressure sensor | |
B602 | Fuel temperature sensor | B622 | Rail pressure sensor | |
B604 | Oil pressure sensor | B638 | Fuel filter module pressure sensor | |
B606 | Exhaust coolant temperature sensor | CAN 4 | Drive train CAN | |
B607 | Intake coolant temperature sensor | S600 | Engine start and engine stop button | |
B608 | Charge air pressure and temperature sensor in charge air pipe | Y621 | Exhaust gas recirculation positioner |
The operating condition of the engine is determined based on input values from the following sensors:
Crankshaft position sensor (B600)
Camshaft position sensor (B601)
Fuel temperature sensor (B602)
Exhaust coolant temperature sensor (B606)
Intake coolant temperature sensor (B607)
Charge air pressure and temperature sensor in charge air pipe (B608)
Temperature sensor downstream of air filter (B611) (only for engine version Euro VI Standard)
Charge air temperature sensor in charge air distributor (B617)
Exhaust gas recirculation (EGR) differential pressure sensor (B621)
Rail pressure sensor (B622)
Fuel filter module pressure sensor (B638)
The torque request, which is calculated by the drive control (CPC) control unit (A3) from (among other things) the position of the accelerator pedal, is routed via the drive CAN (CAN 4) to the engine management (MCM) control unit (A4), which in turn sends the current actual torque and the maximum possible torque to the drive control (CPC) control unit (A3).
It is also possible to exchange information with other electronic systems or control units via the drive CAN (CAN 4) and the drive control (CPC) control unit (A3).
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Output signals, shown on engine 471.9 |
A4 | Engine management control unit (MCM) | Y612 | Cylinder 5 fuel injector | |
CAN 4 | Drive train CAN | Y613 | Cylinder 6 fuel injector | |
Y608 | Cylinder 1 fuel injector | Y621 | Exhaust gas recirculation positioner | |
Y609 | Cylinder 2 fuel injector | Y624 | Engine brake solenoid valve, stage 1 | |
Y610 | Cylinder 3 fuel injector | Y625 | Engine brake solenoid valve, stage 2 | |
Y611 | Cylinder 4 fuel injector | Y642 | Quantity control valve |
After evaluation of the input signals, the engine management (MCM) control unit (A4) actuates the following components depending on the operating state of the engine and the torque request from the drive control (CPC) control unit (A3):
Cylinder 1 fuel injector (Y608)
Cylinder 2 fuel injector (Y609)
Cylinder 3 fuel injector (Y610)
Cylinder 4 fuel injector (Y611)
Cylinder 5 fuel injector (Y612)
Cylinder 6 fuel injector (Y613)
Exhaust gas recirculation positioner (Y621)
Quantity control valve (Y642)
If a fault occurs on the drive train CAN (CAN 4) or on a system component for the engine management, the engine management (MCM) control unit (A4) proceeds according to a clearly defined pattern depending on the severity of the fault. Thus it will fall back on replacement values for less severe faults such as the failure of a sensor while it will go into emergency mode for severe faults such as failure of the drive CAN (CAN 4).
The driver is able to at least drive to the nearest workshop if there is a fault in the system.
The engine management (MCM) control unit (A4) is a component part of the DAS. In connection with a Mercedes Benz transmission, the transmission control unit (TCM) (A5) also belongs in the network. If one of these control units is replaced, this must be taught in via diagnostics in the DAS.