DAF LF45, LF55 Series. Manual — part 478

©

200436

1-9

General

BRAKING PERFORMANCE AND BRAKE EQUALISATION

ΛΦ45/55 series

6

5

1.6 EC BAND FOR A LADEN TRUCK/TRAILER COMBINATION

The "EC band" indicates the limits within which

the deceleration value must lie.

The "EC band" applies to:

-

truck with conventional brake system.

-

trailer with conventional or EBS brake

system.

Note:

The following applies to mid-axle trailers fitted

with air brakes:

The permissible ratio between the deceleration

and the pressure at the yellow coupling head of a

laden mid-axle trailer with air brakes should be

within the two areas derived from the EC band for

a laden truck/trailer combination, for which the

vertical scale has been multiplied by 0.95.

100

%

90

80

70

60

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40

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10

0

1

0

2

3

4

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8

R600880

P (bar)

EBS

EBS

a

EBS

BRAKING PERFORMANCE AND BRAKE EQUALISATION

1-10

©

200436

General

5

ΛΦ45/55 series

6

©

200436

2-1

Inspection and adjustment

BRAKING PERFORMANCE AND BRAKE EQUALISATION

ΛΦ45/55 series

6

5

2. INSPECTION AND ADJUSTMENT

2.1 INSPECTING AND ADJUSTING BRAKE EQUALISATION OF NON-EBS

TRUCK WITH NON-EBS TRAILER VEHICLE

Inspecting brake equalisation of non-EBS
truck with non-EBS trailer vehicle
1.

Take a test drive and evaluate the braking

behaviour.

2.

In the case of disc brakes, inspect the

mechanical condition of the brake calliper,

brake disc and brake pads. In the case of

drum brakes, inspect the mechanical

condition of the brake drums and brake

linings. Their condition may provide clues to

the settings that need to be made.

3.

Perform a brake equalisation test using a

brake dynamometer and fill in the "Brake

equalisation form for brake dynamometer".

See "General".

4.

Evaluate the brake equalisation of the

combination using the "EC band graph". The

combination is correctly balanced if the

braking performance at 2 - 3 bar for the truck

and the trailer vehicle are in a comparable

position in the appropriate EC band, i.e. both

in the upper part, both in the lower part or

both in the middle part.

Note:

On a tractor/drawn vehicle combination the

values for the drawn vehicle may be slightly

lower than those for the prime mover. The

deceleration values for the truck and the

drawn vehicle of a truck/trailer combination

should be the same. The reason for this lies

in the dynamic axle load displacement,

which on semi-trailers causes a transfer of

weight to the tractive unit, whereas on

trailers it does not cause a transfer of weight

to the tractive unit.

5.

Due to the adjustment of the brake pressure

advance on the truck and/or trailer vehicle

the deceleration lines in the "EC band graph"

can be affected.

Note:

For optimum interchangeability of vehicles,

the correct choice between these two

alternatives must be made.

BRAKING PERFORMANCE AND BRAKE EQUALISATION

2-2

©

200436

Inspection and adjustment

5

ΛΦ45/55 series

6

6.

If the mechanical condition of the wheel

brakes, the results of the test drive and the

data obtained from the brake equalisation

test using the brake dynamometer give

cause for doing so, the brake pressure

advance of the trailer vehicle control valve

can be adjusted.

Adjusting brake equalisation of non-EBS
truck with non-EBS trailer vehicle
1.

When the brake pressure advance in the

trailer vehicle control valve on the truck is

increased or decreased, the position of the

curve for the trailer vehicle (B) in the graph

will not be affected. This is because the

reference pressures are measured at the

yellow coupling head (= service line). For the

same reason, however, the curve for the

truck (A) will shift to the right or the left (will

appear to be lower or higher respectively).

So the horizontal axis indicates how much

the brake pressure advance has to be

changed. Reducing the brake pressure

advance results in increased deceleration of

the truck. Increasing the brake pressure

advance results in decreased deceleration of

the truck.

Note:

Increasing the brake pressure advance on

the trailer vehicle reaction valve on the trailer

vehicle results in increased deceleration of

the trailer vehicle.

Bear in mind that an increase in the

brake pressure advance does not

necessarily improve the braking

performance of the trailer vehicle. It

only means that the brake pressure

balance between prime mover and

trailer vehicle is changed. Moreover,

in the event of an emergency stop

the poorer braking performance of

the trailer vehicle will again be

noticeable, as the brake pressure

advance is eliminated when the

maximum brake pressure is used.

2.

So the horizontal axis indicates how much

the brake pressure advance has to be

changed.

3.

Take a test run, perform a brake equalisation

test using a brake dynamometer and fill in

the "Brake equalisation form for brake

dynamometer". See "General". If desired or

required, the setting of the trailer vehicle

control valve can be adjusted again.

R600774

0

10

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a

(%)

A

B

1

2

3

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8

p(bar)

}