EDC engine running function

W07.12-0019-06

1 Fuel rack

2 Control sleeve injection pump

3 Needle motion sensor

4 Control module with atmospheric pressure sensor

5 CAN (databus to FMR)

6 Control sleeve solenoid

7 Fuel quantity actuator solenoid

8 Fuel rack position sensor

9 Fuel temperature sensor

10 ELAB (electric engine stop)

11 Coolant temperature sensor

12 Charge air temperature sensor

13 Charge air pressure sensor

14 EDC speed sensor

The optimum fuel/air mixture must be available at the correct moment in all operating conditions when driving. This in turn results in the principal task of the EDC, the

quantity control, and the

start of injection control.

Correct operation of the fuel quantity and control sleeve actuator of the control sleeve injection pump by the EDC control module is the basis for satisfying this requirement.

Feedback signals to the EDC control module from the control sleeve injection pump come from the fuel rack position sensor (delivery quantity signal) and the from the needle motion sensor (start of injection signal).

When driving, driver control inputs are passed on to the FMR control unit (for example the processed quantity input on the basis of the accelerator pedal position), or control inputs stored in the control module (for example the specified vehicle speed set by means of the Tempomat/Temposet operating lever) over the CAN databus to the EDC control module. These in turn result in control tasks in respect of complying with the control input while at the same time accurately determining the optimum quantity of fuel and optimum start of injection.

Control tasks:

- Controlling idle speed

- Controlling processed quantity input from the accelerator pedal

- Controlling start of injection

- Controlling working speed of the power take-off (in addition, various connection facilities at the FMR control module permit various control characteristics and operating facilities)

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- Controlling torque and limiting smoke in exhaust

- Controlling vehicle speed

In the inertia fuel shutoff mode, engine brake and constant throttle are used as a continuous operation brake from an engine speed of 900 rpm. Both are actuated through a solenoid valve which, on vehicles without a retarder, is operated by means of the engine brake foot switch and, otherwise, by the operating lever for the retarder (stage 1 to 5) through the FMR control module. The EDC control module ensures that the fuel quantity actuator of the control sleeve injection pump is in the zero delivery position as no fuel is supplied during inertia fuel shutoff.

Control of idling speed

 Stored value in/driver input to the FMR control module:

- idling base speed (specification approx. 560 rpm), or

- idling specified speed by means of stepless setting (up to approx. 740 rpm) at Tempomat/Temposet operating lever.

 Actual speed to FMR control unit by FMR speed sensor.

 Following data transfer with the EDC control module, the idling set speed is subsequently adjusted in the case of, for example, load change resulting from PTO being engaged, by the EDC control module in a similiar way as for RQV characteristic.

 The idling specified speed can be programmed low and the vehicle can also be started off without operating the accelerator (to save wear and tear on the clutch).

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Controlling quantity input from accelerator

 Driver input to the FMR control module:

Quantity input through food throttle actuator as a function of accelerator pedal position.

 The servo control of the accelerator pedal in the FMR control module results in the processed quantity input for data transfer with the EDC control module.

 Following data transfer with the EDC control module, the processed quantity input is controlled by the EDC control module. The fuel quantity actuator of the control sleeve injection pump is actuated in the same way as a minimum/maximum speed governor with RQ characteristic.

 As the map for drivability is programmable, it is also possible to achieve other or further optimized control characteristics.

The necessary control adjustments on the basis of changes in load states and ambient conditions are achieved by detecting the engine speed (EDC speed sensor), the charge pressure (charge pressure sensor), the charge air temperature (charge air temperature sensor) and the fuel temperature (fuel temperature sensor).

Controlling start of injection

The EDC control module monitors the start of injection signals of the needle motion sensor. The control module detects the

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position 10° after top dead center (TDC/OT) from the EDC primary speed sensor.

The time offset is detected in this way and the start of injection can be controlled by actuating the control sleeve actuator of the control sleeve injection pump in relation to the TDC. Maps stored in the EDC control module determine the optimum start of injection on the basis of relevant parameters (e.g. engine speed, flow time through injection lines, accelerator pedal input). Start of injection control also necessitates detecting engine speed by means of the FMR speed sensor.

 If the EDC speed sensor or the needle motion sensor is faulty, an open-loop control is activated for determining start of injection. The start of injection can be controlled in this case by means of the on/off ratio of the square-wave voltage at the control sleeve solenoid. The values required for this are stored in a map in the EDC control module.

Controlling torque and limiting exhaust smoke

Constant corrections of the fuel quantity and of start of injection are performed with the aid of maps as a function of the constantly changing parameters when driving of charge air temperature, fuel temperature, charge pressure, atmospheric pressure and engine speed, in order to protect the engine and drive train from excessive loads and to minimize the impact on the environment of exhaust smoke.

 As the software (maps) can be quickly developped and modified, it will a simpler matter in future to implement further reductions in pollutant emissions.

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Controlling the working speed of the power take-off

 Driver input to the FMR control module:

The specified speed of the power take-off is input in line with the power take-off function selected ( adaptation to various power take-offs).

The working speed can either be set steplessly at the Tempomat/Temposet operating lever or with the accelerator pedal (manual throttle actuator), or a fixed, programmed working speed is used for the further control.

 On models fitted with E-modules without "1600 rpm" sticker, the working speed cannot be set by means of the operating lever. The desired working speed is not stored.

 Following data transfer with the EDC control module, the specified speed of the power take-off is subsequently adjusted by the EDC control module on the basis, for example, of the load change caused by the power take-off. Various control characteristics are programmed in this control module.

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Adaptation to various power take-offs

Individual adaptation to various power take-offs is possible as a result of the connection facilities at the E-module:

- Engine speed control with a fixed working speed based on RQV characteristic.

1. Setting of specified speed by manual programming or with the HHT.

Provision for transmission-dependent power take-offs.

2. Connection possible for live/fixed power take-off.

- Engine speed control with steplessly adjustable working speed based on RQV characteristic.

1. Setting of specified speed by means of the accelerator pedal (manual throttle actuator) or Tempomat/Temposet operating lever up to limit speed. The parking brake must be operated. Provision for transmission-dependent power take-offs. A working speed set with the Tempomat/Temposet operating lever is reset when the foot throttle actuator is operated in line with its position.

2. Working speed can also be controlled alternatively only in transmission neutral position.

- Engine speed control with steplessly adjustable working speed based on RQ characteristic.

1. Stepless setting of specified speed by means of the accelerator pedal (manual throttle actuator) up to limit speed. Provision for live power take-offs.

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Controlling vehicle speed

 Driver input to FMR control module:

Set driving speed (Tempomat) by means of stepless setting at Tempomat/Temposet operating lever (up to parameterized limit speed), or respectively defining a maximum vehicle speed (Temposet).

 Actual speed to FMR control module:

- C3-signal from I-module of tachograph.

 Tempomat/Temposet in FMR control module and data transfer to the EDC control module for implementation of Tempomat function at engine.

 The Tempomat function is switched off in the event of operation of the service or continuous brake, the clutch, the Temposet pushbutton at the operating lever, or if the automatic transmission is shifted into position N, or if vehicle speed drops below 45 km/h, or if certain faults occur at the FMR system.