Engine control (MR) function

W07.15-1281-79

Extended vehicle network, shown on

Engine 541.9

0 Ignition OFF

1 C. 15R ON

2 Circuit 15 ON

3 Kl.50

4 Engine CAN bus

5 Vehicle CAN bus

Components.

A3 Drive control (FR) control unit

A4 Flame starting system control unit (FLA)

A6 MR/PLN control unit

A16 GS/EPS control unit

A22 PSM control unit

A42 WSP control unit

B1 Foot throttle actuator

B10 Fuel temperature sensor
- Only on engine 541.9 up to engine end no. 094097 and
engine 542.9 up to engine end no. 094246

B11 Oil temperature sensor

S108 Switch, ADR

Y5 Flame starting system solenoid valve

Y6 Cylinder 1 unit pump

Y7 Cylinder 2 unit pump

Y8 Cylinder 3 unit pump

Y9 Cylinder 4 unit pump

Y10 Cylinder 5 unit pump

Y11 Cylinder 6 unit pump

Y46 PTO 1 solenoid valve

Y47 PTO 2 solenoid valve

Y48 PTO 3 solenoid valve

Z1 CAN star point cab dash support

* Engine 541.9 up to engine end no. 106266 and engine 542.9 up to engine end no. 109389

** Engine 541.9 as of engine end no. 106267 and engine 542.9
as of engine end no. 109390

*** Only for vehicles with code (GS1) Gearshift "mechanical" or code (GS3) Gearshift "hydraulic"

B15 Crankshaft angle position sensor

B16 Cylinder 1 TDC sensor

B60 Gear sensor

B61 Gate sensor

B65 Coolant temperature sensor

B111 Charge air combination sensor (temperature, pressure)

M1 Starter

P2 Instrument

R3 Flame glow plug

S1 Drive switch

S2 Engine control/permanent brake operating lever

S9 Neutral position switch

S10 Engine start pushbutton switch

S10.1 Pushbutton, engine start/stop

S11 Engine stop pushbutton switch

S23 PTO 1 indicator switch

S64 PTO 1 switch

S65 PTO 2 switch

S66 PTO 3 switch

S79 PTO 2 indicator switch

S80 PTO 3 indicator switch

Involved systems

a) Engine control (MR)

b) Flame starting system (FLA)
- Only for vehicle with code (M89) Flame starting system

c) Drive control (FR)

d) Instrument (INS)
- from 01.01.2000

e) Instrument (INS)
- up to 31.12.1999

g) Gear control (GS)
- Only for vehicle with code (GS2) Gear control

f) Parameterizable special module (PSM)
- Only for vehicles with code (ED5) parameterizable special module (PSM), code (EM7) parameterizable special module with body CAN bus or code (EM8) parameterizable special module with body and trailer CAN bus

General information

The engine control (MR) is a self-standing, electronic system whose main task is to regulate or control the injection process of the Pump-Line-Nozzle system (PLN system). It ensures that the engine runs as economically, pollutant-free and low-noise as possible under all operating conditions.

Function

The central control unit on the engine control (MR) is the MR/PLN control unit (A6). Depending on the operating condition of the engine and torque requirements dictated by the drive control (FR) control unit (A3), the MR/PLN control unit calculates the optimal injection begin time as well as the required injection quantity, and therefore ensures that the fuel is injected (Y6 up to Y11) the correct point in time and that the correct amount is always injected into the cylinder through exact, electrical actuation of solenoid valves in the unit pumps .

The operating condition of the engine is determined based on incoming values from the following sensors:

 Crankshaft angle position sensor (B15),

 TDC sensor cylinder 1 (B16),

 Charge air combination sensor (temperature, pressure) (B111),

 Coolant temperature sensor (B65) and

 Fuel temperature sensor (B10).

 The fuel temperature sensor (B10) has been installed for engine 541.9 only up to engine end no. 094097 and for
engine 542.9 only up to engine end no. 094246.
The fuel temperature for all other engines (engine 541.9 as of engine end no. 094098 and engine 542.9 as of engine end no. 094247) is determined over a performance map.

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While consumption, performance and exhaust related size parameters are detected over the charge air combination sensor (temperature, pressure) (B111), the coolant temperature sensor (B65) and, if installed, the fuel temperature sensor (B10), the MR/PLN control unit (A6) detect the current rotational speed as well as the rotational angle relative to top dead center (engine position) over the crankshaft angle position sensor (B15) and the compression cycle of the 1st cylinder in connection with the TDC sensor on cylinder 1 (B16).

The torque requirement which is determined by the drive control (FR) control unit (A3) from a number of parameters including the position of the foot throttle actuator (B1), passes over the engine CAN bus (4) to the MR/PLN control unit (A6), which in turn sends the current actual torque and the possible maximum torque to the drive control (FR).

There is also the possibility over the engine CAN bus (4) that information is exchanged with other electronic systems such as the instrument (P2) and the parameterizable special module control unit (A22).

Thus the MR/PLN control unit (A6), for example, sends engine-specific data such as oil pressure, oil temperature, oil level and rotational speed over the engine CAN bus (4) to the drive control (FR) control unit (A3) which in turn sends this over the vehicle CAN bus (5) into the instrument (P2) to the display.

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If a fault arises on the engine CAN bus (4) or a system component, the engine control (MR) follows a precisely established procedure according to the gravity of the malfunction. Thus it refers in less serious cases such as the loss of a sensor to substitute values while in serious cases such as failure of a CAN connection it will put the system in emergency mode

It is therefore possible if there is a malfunction in the system for the driver to at least take the vehicle to the next workshop.