Content .. 98 99 100 101 ..

DAF XF105. Manual - part 100

200528

3-19

Control functions

DMCI ENGINE MANAGEMENT SYSTEM

XF105 series

3.10 SMOKE LIMITATION

This function ensures that emissions of black

smoke are kept to a minimum level. The fuel-air

ratio is responsible for the development of

smoke. The DMCI electronic unit calculates

smoke limiting on the basis of the inlet air

pressure (F649, pin A34) that is compensated by

the inlet air temperature (F649, pin A30). To

calculate the mass of the intake air, the electronic

unit requires the inlet air temperature, the inlet air

pressure and the intake air volume. The latter can

be calculated on the basis of the cubic capacity

and the speed of the engine. When the intake air

mass has been calculated, the electronic unit can

determine the maximum amount of fuel that can

be injected to prevent excessive development of

smoke.

If the inlet air boost pressure signal is absent or is

not correct, the electronic unit carries out

calculations using an air mass table based on the

engine speed (F552).

Relevant components

Charge boost pressure and temperature

sensor (F649)

Crankshaft sensor (F552)

Injectors (B421 to B426)

i401000

D965

1 2

high-side

low-side

Cyl.6

B426

1 2

high-side

low-side

Cyl.5

B425

1 2

high-side

low-side

Cyl.4

B424

1 2

high-side

low-side

Cyl.3

B423

1 2

high-side

low-side

Cyl.2

B422

1 2

high-side

low-side

Cyl.1

Injectors

B421

temp.

F649

2 1

signal

ground

3 4

supply 5V

signal

inlet

pres.

boost

2 1

signal

return

shield

F552

speed

crankshaft

A22

A21

A14

A18

A13

A10

A17

A34

A27

A28

A30

A49

A50

A60

DMCI ENGINE MANAGEMENT SYSTEM

3-20

200528

Control functions

XF105 series

3.11 ENGINE BRAKE CONTROL

The engine brake consists of an exhaust brake

and, if fitted, a DEB (DAF Engine Brake). The

engine brake can be activated by the driver

(direct activation) or by another vehicle system

(indirect activation).

Direct activation

The vehicle can be equipped with two engine

brake switches, a standard floor switch (E564)

and a steering column switch (C907) if the vehicle

is not equipped with an intarder. Both switches

are linked to VIC-2 (D310). VIC-2 sends a CAN

message to DMCI to activate the engine brake.

When the CAN message is received from VIC-2

the exhaust brake valve (B192) and, if fitted, the

DEB valves (B411 to B416) are actuated.

However, the DCMI also takes into account other

vehicle conditions (e.g. engine speed, vehicle

speed and activation of ABS). When the engine

brake is active, no fuel is injected until the

engine speed drops to just above idling speed

i400995

D965

1 2

high-side

low-side

Cyl.6

B416

1 2

high-side

low-side

Cyl.5

B415

1 2

high-side

low-side

Cyl.4

B414

1 2

high-side

low-side

Cyl.3

B413

1 2

high-side

low-side

Cyl.2

B412

1 2

high-side

low-side

DEB valves

Cyl.1

B411

shield

B192

valve

exh. brake

signal

supply

C60

C61

C62

Accelerator

Pedal Sensor

Vehicle

CAN2

low

Vehicle
CAN2
high

E184
(10A)

2 1

signal

return

F552

speed

crankshaft

A38

C28

A49

A50

A60

A44

A43

A56

A55

A40

A39

A48

A47

A35

A52

A51

ground

signal

supply 5V

ground

signal

CAN2 low

CAN2 high

B A

C D F

F672

B37

B33

B34

B38

B41

B53

B45

Vehicle

CAN1

low

Vehicle
CAN1
high

CAN1 low

CAN1 high

B35

B27

B40

ground

gearbox

E599

switch
neutral pos.

E593

switch
neutral pos.

ground

gearbox

kl.15

cabin

ground

E013
(10A)

B36

E575

HALL

clutch

switch

200528

3-21

Control functions

DMCI ENGINE MANAGEMENT SYSTEM

XF105 series

(approx. 800 rpm). The engine brake is then

disengaged and fuel is injected again after a

small delay. The DEB valves (B411 to B416) are

simultaneously and continuously actuated during

activation of the engine brake.

AS Tronic receives a CAN message via V-CAN1

if the engine speed is not optimal for engine brake

use. If the speed is too low, AS Tronic will change

down until the engine speed falls within the

engine speed range for which the engine-brake

capacity is optimal.

Activation via the floor switch (E564)
If the floor switch is pressed then VIC-2 sends a

CAN message via V-CAN2 to DMCI to operate

the engine brake.

The engine brake can only be engaged if the

conditions below are satisfied:

The engine speed must be higher than a

programmed value and

the vehicle speed must be higher than a

programmed value and

the ABS control must not be active.

clutch pedal switch not active

neutral position switch not operated

idling switch may not be operated

DMCI ENGINE MANAGEMENT SYSTEM

3-22

200528

Control functions

XF105 series

Activation via steering column switch (C907)
If the floor switch is not activated then the engine

brake can be activated by briefly moving the

steering column switch to the "ON" position (2).

The steering column switch is a spring-loaded

switch in this direction and returns after operation

to the centre position.

Activating the engine brake using the steering

column switch is only possible if the following

requirements are met:

Idling switch not active (accelerator pedal not

operated)

Cruise control switch "SET-", "SET+" and

"RES" not active

The engine brake activation using the steering

column switch is deactivated if one of the

following requirements is met:

Steering column switch is in the "OFF"

position (1)

Idling switch is active (accelerator pedal

operated)

Cruise control switch "SET-", "SET+" and

"RES" active

Clutch pedal depressed

Neutral position switch operated

Note:

The engine brake is deactivated during the

activation of the clutch switch and/or the

neutral position indicator (therefore not if the

drive line is interrupted). If these switches

are no longer active then the engine brake

will be reactivated.

Indirect activation
The engine brake can also be activated at the

request of another system such as the intarder

(EST-42) and EBS-2.

- EBS-2

If EBS-2 sends the CAN message "EBS brake

switch" via V-CAN2 to DMCI then DMCI will

support vehicle braking by activating the engine

brake.

This is the "third brake integration" function. This

protects the brake lining during normal braking.

This "third brake integration" function can also be

deactivated using a dashboard switch.

i401010

i401011

Content .. 98 99 100 101 ..