DAF CF65, CF75, CF85 Series . Manual — part 933

©

200423

1-9

General

BRAKING PERFORMANCE AND BRAKE EQUALISATION

ΧΦ65/75/85 series

6

6

1.5 EC BAND FOR A LADEN TRACTOR/SEMI-TRAILER COMBINATION

The "EC band" indicates the limits within which
the deceleration value must lie.

The "EC band" applies to:
-

tractor with conventional brake system

-

semi-trailer with conventional or EBS brake
system

100

%

a

90

80

70

60

50

40

30

20

10

0

1

0

2

3

4

5

6

7

8

R600881

EBS

EBS

P (bar)

EBS

BRAKING PERFORMANCE AND BRAKE EQUALISATION

1-10

©

200423

General

6

ΧΦ65/75/85 series

6

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

50

40

30

20

10

0

1

0

2

3

4

5

6

7

8

R600880

P (bar)

EBS

EBS

a

EBS

©

200423

2-1

Inspection and adjustment

BRAKING PERFORMANCE AND BRAKE EQUALISATION

ΧΦ65/75/85 series

6

6

2. INSPECTION AND ADJUSTMENT

2.1 CHECKING BRAKING PERFORMANCE ON EBS TRUCK

It is not easy to perform a realistic braking
deceleration test or braking deceleration
calculation on a vehicle that is not fully laden and
is fitted with an EBS system on a test bench.

The reason for this is that the EBS system has its
own control principle which calculates the
optimum brake pressure to the front and rear
axles in relation to the dynamic axle loads.

Note:
The test bench function and deceleration
measurement can be carried out on a vehicle with
the EBS system in fully laden state, if desired.

It is however possible to inspect the brake
performance of the vehicle by means of braking
force measurements, though only the static
condition of the brake system can be assessed.

Inspection, brake performance

1.

The brake performance of the vehicle can be
inspected by placing the fully laden vehicle
on a test bench and then activating the test
bench function of the EBS system.

2.

The braking forces must be measured on a
brake system with warm brakes
(temperature under normal operating
conditions).

3.

The braking forces cannot be evaluated until
the brake lining has bedded in.

4.

The braking forces must be measured in
relation to the pressure in the brake cylinder.

5.

Based on the relevant graph (see "Technical
data"), determine whether the braking
performance is correct. An example is used
to explain how the measured braking
performance should be evaluated.

BRAKING PERFORMANCE AND BRAKE EQUALISATION

2-2

©

200423

Inspection and adjustment

6

ΧΦ65/75/85 series

6

The braking forces are increased, from 2 bar,
in increments of 0.5 bar, until the rolling bench
turns off. This yields several points that
are plotted out in the graph; when the dots are
connected, a line such as line (1) results.
If this line (1) is equal to or above the reference
line, the measured braking performance is
correct. If the line is below the reference line,
such as example line (2), the measured braking
performance is not correct and the mechanical
condition of the basic braking system must be
inspected.

Activating test bench function on EBS truck
In the test bench function, the EBS control
function is switched off and a switchover is made
to a test function with accompanying curve.

In this test function, it is possible to inspect the
brake performance.

Test function curve
-

The output pressures to the front axle and
rear axle are those as with a fully laden
vehicle.

-

The pressure ratio control between front and
rear axles is not active (pressure ratio 1:1).

-

The command pressure to the drawn vehicle
has a reading in the middle of the EC brake
band.

-

The brake functions such as deceleration
control, wheel slip control etc. are switched
off.

Condition for being able to activate the test
function
At least one of the axles must have a wheel
speed lower than 2 km/h. On all other axles,
the wheel speed must be lower than 12 km/h.

Note:
This means that both on a vehicle which has not
been on the test bench (stationary vehicle) and
on a vehicle that has been on the test bench,
the test function can be activated.

2

2,5

3

3,5

4

4,5

6000

5500

5000

4500

4000

3500

3000

2500

2000

9"-125

R600883

235/75R17,5

P (bar)

F (N)

1

2