Commission Delegated Regulation (EU) 2015/68Show full title

ANNEX III Requirements applying to the measurement of the response time

1. General Requirements

1.1. The response time for the service braking systems shall be determined with the vehicle stationary, the pressure being measured at the opening of the least favourably placed brake. For vehicles equipped with load sensing valves, these devices shall be set in the ‘laden’ position.

1.2. During the tests, the stroke of the brake cylinders of the individual axles shall be that corresponding to the most closely adjusted brakes.

1.3. Response times obtained in conformity with points 2.2, 2.3, 2.4, 2.6, 3.3, 3.4, 3.5, 3.6.5, 4.1, 4.5.1, 4.5.2, 4.5.3, 5.3.6, 6.2, shall be rounded to the nearest tenth of second. If the figure representing the hundredth units is 5 or more, the response time is rounded to the upper tenth.

1.4. The diagrams in Appendices 1 and 2 give examples of the correct configuration of the relevant simulators for setting and use.

2. Tractors equipped with compressed-air braking systems

2.1. At the beginning of each test, the pressure in the energy storage device shall be equal to the pressure at which the governor restores the feed to the system. In systems not equipped with a governor (e.g., pressure-limited compressors) the pressure in the energy storage device at the beginning of each test shall be 90 % of the pressure specified by the manufacturer and specified in point 1.2.2.1 of Part A of Annex IV, used for the tests prescribed in this annex.

2.2. The response times as a function of the actuating time (t_f) shall be obtained by a succession of full actuations, beginning with the shortest possible actuating time and increasing to a time of about 0,4 seconds. The measured values shall be plotted on a graph.

2.3. The response time to be taken into consideration for the purpose of the test is that corresponding to an actuating time of 0,2 seconds. This response time can be obtained from the graph by interpolation.

2.4. For an actuating time of 0,2 seconds, the time elapsing from the initiation of the braking system control device actuation to the moment when the pressure in the brake cylinder reaches 75 % of its asymptotic value shall not exceed 0,6 seconds.

2.5. In the case of tractors having a pneumatic control line for towed vehicles, in addition to the requirements of point 1.1, the response time shall be measured at the extremity of a pipe 2,5 m long with an internal diameter of 13 mm which shall be joined to the coupling head of the control line of the service braking system. During this test, a volume of 385 ± 5 cm³ (which is deemed to be equivalent to the volume of a pipe 2,5 m long with an internal diameter of 13 mm and under a pressure of 650 kPa) shall be connected to the coupling head of the supply line. The length and internal diameter of the pipes shall be entered at item 2.4 of the test report.

2.6. The time elapsing from the initiation of brake-pedal actuation to the moment when:

2.6.1.

The pressure measured at the coupling head of the pneumatic control line;

2.6.2.

The digital demand value in the electric control line measured according to ISO 11992:2003, including ISO 11992-2:2003 and its Amd.1:2007, reaches x per cent of its asymptotic, respectively final, value shall not exceed the times shown in the table below:

x [per cent]	t [s]
10 75	0,2 0,4

2.7. In the case of tractors authorised to tow vehicles of category R3 or R4 fitted with compressed-air braking systems, in addition to the requirements in point 2.6., the prescriptions in point 2.2.1.17.2.1 of Annex I shall be verified by conducting the following test:

2.7.1.

by measuring the pressure at the extremity of a pipe 2,5 m long with an internal diameter of 13 mm which shall be joined to the coupling head of the supply line;

2.7.2.

by simulating a failure of the control line at the coupling head;

2.7.3.

by actuating the service braking control device in 0,2 seconds, as described in point 2.3.

3. Tractors equipped with hydraulic braking systems

3.1. The response time tests shall be carried out at an ambient temperature between 15 °C and 30 °C.

3.2. At the beginning of each test, the pressure in the energy storage device shall be equal to the pressure at which the governor restores the feed to the system. In systems not equipped with a governor (e.g., pressure-limited hydraulic pumps) the pressure in the energy storage device at the beginning of each test shall be 90 % of the pressure specified by the manufacturer and specified in point 1.2.1.2 of Part C of Annex IV, used for the tests prescribed in this annex.

3.3. The response times as a function of the actuating time (t_f) shall be obtained by a succession of full actuations, beginning with the shortest possible actuating time and increasing to a time of about 0,4 seconds. The measured values shall be plotted on a graph.

In the case of a service braking system which is activated with no or only a limited assistance of energy a control force shall be applied which ensures at least the prescribed service braking performance.

3.4. The response time to be taken into consideration for the purpose of the test is that corresponding to an actuating time of 0,2 seconds. This response time can be obtained from the graph by interpolation.

3.5. For an actuating time of 0,2 seconds, the time elapsing from the initiation of the braking system control device actuation to the moment when the pressure in the brake cylinder reaches 75 % of its maximum values hall not exceed 0,6 seconds.

In the case of a full powered service braking system where the brake pressure in the brake actuator reaches a temporary maximum pressure which then falls to the mean stabilised pressure. This mean stabilised pressure should be taken for the calculation of the 75 % value.

3.6. Tractors equipped with a hydraulic control line for towed vehicles

3.6.1. In addition to the requirements of point 1.1, the response time shall be measured with a towed vehicle simulator (see point 1. of Appendix 2) which shall be joined to the coupling heads of the hydraulic control line and the supplementary line of the tractor.

3.6.2. The towed vehicle simulator shall have the following components and characteristics:

3.6.2.1. Supplementary line towed vehicle simulator

3.6.2.1.1. Supplementary line with a female coupling corresponding to ISO 16028:2006 having an orifice with a diameter of 0,6^{+ 0,2} mm in order to limit its flow during the test.

3.6.2.1.2. Piston accumulator (or equivalent device) complying with the following characteristics and test conditions:

3.6.2.1.2.1.

Nominal volume of 1 000 cm³;

3.6.2.1.2.2.

Initial precharge pressure of 1 000^{± 100} kPa at a displaced volume of 0 cm³;

3.6.2.1.2.3.

Maximum pressure of 1 500 kPa at a displaced volume of 500^{± 5} cm³.

3.6.2.1.3. The piston accumulator (or equivalent device) is connected with the supplementary line via a connection with an internal diameter of 12,5 mm consisting of a flexible pipe (according to EN853:2007) of 1,0 m length.

3.6.2.1.4. A testing port shall be provided as close as possible to the female ISO 16028:2006 coupling.

3.6.2.1.5. In order to be able to bleed the simulator before and after the test a bleeding device shall be provided.

3.6.2.2. Control line towed vehicle simulator

3.6.2.2.1. Control line with a female coupling corresponding to ISO 5676:1983

3.6.2.2.2. Energy storage device with piston (or equivalent device) complying with the following characteristics and test conditions:

3.6.2.2.2.1.

Initial precharge pressure of 500^{± 100} kPa at a displaced volume of 0 cm³

3.6.2.2.2.2.

Intermediate test pressure of 2 200^{± 200} kPa at a displaced volume of 100^{± 3} cm³

3.6.2.2.2.3.

Final pressure of 11 500^{± 200} kPa at a displaced volume of 140^{± 5} cm³

3.6.2.2.3. The energy storage device with piston (or equivalent device) is connected with the control line via a connection with an internal diameter of 10 mm consisting of a flexible pipe (according to EN853:2007) of 3,0 m and a rigid pipe of 4,5 m length

3.6.2.2.4. Testing ports shall be provided as close as possible to the energy storage device with piston (or equivalent device) and to the female ISO 5676:1983 coupling.

3.6.2.2.5. In order to be able to bleed air from the connection pipes before the test a bleeding device shall be provided

3.6.3. The test shall be performed under the following conditions:

3.6.3.1.

the connection pipes shall be bleeded from air before the test;

3.6.3.2.

the engine speed of the tractor shall be at 25 % above idling speed;

3.6.3.3.

the bleeding device of the supplementary line towed vehicle simulator shall be fully opened.

3.6.4. With regard to the measuring of the response time according to points 3.3 and 3.4, the brake control force shall be such to obtain at least a pressure of 11 500 kPa on the coupling head of the control line with the engine running at 25 % above idling speed.

3.6.5. For an actuating time of 0,2 seconds, the time elapsing from the initiation of the braking system control device to the moment when the pressure measured at the testing port close to energy storage device with piston (or equivalent device) reaches 75 % of its maximum value according to point 3.5 shall not exceed 0,6 seconds.

However, the maximum value relates here to the pressure measured at the testing port instead of the brake pressure as in the case of point 3.5.

4. Towed vehicles equipped with compressed-air braking systems

4.1. The towed vehicle's response times shall be measured without the tractor. To replace the tractor, it is necessary to provide a simulator to which the coupling heads of the supply line, the pneumatic control line and/or the connector of the electric control line are connected.

4.2. The pressure in the supply line shall be 650 kPa.

4.3. The simulator for pneumatic control lines shall have the following characteristics:

4.3.1.

It shall have a reservoir with a capacity of 30 litres which shall be charged to a pressure of 650 kPa before each test and which shall not be recharged during each test. At the outlet of the braking control device, the simulator shall incorporate an orifice with a diameter of from 4,0 to 4,3 mm inclusive. The volume of the pipe measured from the orifice up to and including the coupling head shall be 385 ± 5 cm³ (which is deemed to be equivalent to the volume of a pipe 2,5 m long with an internal diameter of 13 mm and under a pressure of 650 kPa). The control line pressures referred to in point 4.3.3 shall be measured immediately downstream of the orifice.

4.3.2.

The control device shall be so designed that its performance in use is not affected by the tester.

4.3.3.

The simulator shall be set, e.g. through the choice of orifice in accordance with point 4.3.1 in such a way that, if a reservoir of 385 ± 5 cm³ is joined to it, the time taken for the pressure to increase from 65 to 490 kPa (10 and 75 per cent respectively of the nominal pressure of 650 kPa) shall be 0,2 ± 0,01 seconds. If a reservoir of 1 155 ± 15 cm³ is substituted for the above-mentioned reservoir, the time taken for the pressure to increase from 65 to 490 kPa without further adjustment shall be 0,38 ± 0,02 seconds. Between these two pressure values, the pressure shall increase in an approximately linear way. These reservoirs shall be connected to the coupling head without using flexible pipes and the connection shall have an internal diameter of not less than 10 mm.

4.3.4.

The diagrams in the Appendix 1 give an example of the correct configuration of the simulator for setting and use.

4.4. The simulator for checking the response to signals transmitted via the electric control line shall have the following characteristics:

4.4.1.

The simulator shall produce a digital demand signal in the electric control line according to ISO 11992-2:2003 and its Amd.1:2007 and shall provide the appropriate information to the towed vehicle via pins 6 and 7 of the ISO 7638:2003 connector. For the purpose of response time measurement, the simulator may at the manufacturer's request transmit to the towed vehicle information that no pneumatic control line is present and that the electric control line demand signal is generated from two independent circuits (see paragraphs 6.4.2.2.24 and 6.4.2.2.25 of ISO 11992-2:2003 and its Amd.1:2007).

4.4.2.

The braking system control shall be so designed that its performance in use is not affected by the tester.

4.4.3.

For the purpose of response time measurement the signal produced by the electric simulator shall be equivalent to a linear pneumatic pressure increase from 0,0 to 650 kPa in 0,2 ± 0,01 seconds.

4.5. Performance requirements

4.5.1. For towed vehicles with a pneumatic control line the time elapsing between the moment when the pressure produced in the control line by the simulator reaches 65 kPa and the moment when the pressure in the brake actuator of the towed vehicle reaches 75 per cent of its asymptotic value shall not exceed 0,4 seconds.

4.5.1.1. Towed vehicles equipped with a pneumatic control line and having electric control transmission shall be checked with the electrical power supplied to the towed vehicle via the ISO 7638:2003 connector (5 or 7 pin).

4.5.2. For towed vehicles with an electric control line the time elapsing between the moment when the signal produced by the simulator exceeds the equivalent of 65 kPa and the moment when the pressure in the brake actuator of the towed vehicle reaches 75 % of its asymptotic value shall not exceed 0,4 seconds.

4.5.3. In the case of towed vehicles equipped with a pneumatic and an electric control line, the response time measurement for each control line shall be determined independently according to the relevant procedure described in points 4.5.1.1 and 4.5.2.

5. Towed vehicles equipped with hydraulic braking systems

5.1. The tests shall be carried out at an ambient temperature between 15 °C and 30 °C.

5.2. The response times of the towed vehicle shall be measured without a tractor. In order to simulate the tractor, it is necessary to provide a tractor simulator to which the coupling heads of the control line and the supplementary line are connected. If the towed vehicle is equipped with an electrical connector as specified in point 2.1.5.1.3 of Annex I, this connector shall also be connected to the tractor simulator (see point 2. of Appendix 2).

5.3. The tractor simulator shall have the following characteristics:

5.3.1.

The tractor simulator shall be fitted with the types of connections as specified in points 2.1.5.1.1 to 2.1.5.1.3 of Annex I with regard to the tractor.

5.3.2.

When the tractor simulator is activated (e. g. by an electrical switch):

5.3.2.1.

a pressure of 11 500^{+ 500} kPa shall be generated on the coupling head of the control line,

5.3.2.2.

a pressure of 1 500^{+ 300} kPa shall be present on the coupling head of the supplementary line.

5.3.3.

When the control line of the towed vehicle is not connected, the tractor simulator shall be capable of generating a pressure of 11 500 kPa at the coupling head of the control line within 0,2 seconds after it was activated (e.g. by an electrical switch).

5.3.4.

The hydraulic fluid used in the tractor simulator shall have a viscosity of 60^{± 3} mm²/s at a temperature of 40^{± 3} °C (e.g. hydraulic fluid according to SAE 10W30). During the tractor simulator test the temperature of the hydraulic fluid shall not exceed 45 °C.

5.3.5.

If the towed vehicle is equipped with hydraulic energy storage devices to comply with the requirements for the service braking system, the energy storage devices shall be charged prior to the response time measurements to a pressure as mentioned by the manufacturer in the test report to achieve the minimum prescribed service braking performance.

5.3.6.

When the tractor simulator is connected to the control line of the towed vehicle simulator (as specified in point 3.6.2) the tractor simulator shall be calibrated in such a way that the time elapsing from the activation of the tractor simulator and the moment when the pressure in the energy storage device with piston (or equivalent device) of the control line of the towed vehicle simulator reaches 11 500 kPa shall be 0,6^{+ 0,1} seconds. To achieve this performance the flow of the tractor simulator shall be adjusted (e.g. by a flow regulator). The connection pipes of the control line of the towed vehicle simulator shall be bleeded from air before this calibration.

5.3.7.

The control device of the tractor simulator shall be so designed that its performance is not effected by the tester.

5.4. Performance requirements

5.4.1. When the calibrated tractor simulator (see point 5.3.6) is connected with the towed vehicle, the time elapsing between the moment when the tractor simulator is activated (e.g. by an electrical switch) and the moment when the pressure in the least favourable brake actuator reaches 75 % of its maximum value shall not exceed 0,6 seconds.

In the case of a service braking system, where the brake pressure in the brake actuator reaches a temporary maximum pressure which then falls to the mean stabilised pressure, the mean stabilised pressure should be taken for the calculation of the 75 % value.

6. Tractors equipped with service braking system using spring brakes

6.1. The response time measurement has to be carried out with the spring brakes adjusted as closely as possible. The initial pressure in the spring compression chamber, corresponding to this testing requirement, shall be specified by the manufacturer.

6.2. The time elapsing from the actuation of the service brake control device (brakes fully released) to the moment when the pressure in the spring compression chamber of the least favourable brake cylinder reaches a pressure corresponding to 75 % of the prescribed braking performance shall not exceed 0,6 seconds.

Appendix 1 Examples of pneumatic simulators

1. Setting the Simulator

2. Testing the Trailer

A

=

supply connection with shut-off valve

C1

=

pressure switch in the simulator, set at 65 kPa and at 490 kPa

C2

=

pressure switch to be connected to the brake actuator of the towed vehicle, to operate at 75 per cent of the asymptotic pressure in the brake actuator CF

CF

=

brake cylinder

L

=

line from orifice O up to and including its coupling head TC, having an inner volume of 385 ± 5 cm³ under a pressure of 650 kPa

M

=

pressure gauge

O

=

orifice with a diameter of not less than 4 mm and not more than 4,3 mm

PP

=

pressure test connection

R1

=

30 litre air reservoir with drain valve

R2

=

calibrating reservoir, including its coupling head TC, to be 385 ± 5 cm³

R3

=

calibrating reservoir, including its coupling head TC, to be 1 155 ± 15 cm³

RA

=

shut-off valve

TA

=

coupling head, supply line

V

=

braking system control device

TC

=

coupling head, control line

VRU

=

emergency relay valve

3. Example of a simulator for electric control lines

ECL

=

Electric Control Line corresponding to ISO 7638:2003

SIMU

=

Simulator of Byte 3,4 of EBS 11 according to ISO 11992:2003 with output signals at start, 65 kPa and 650 kPa

A

=

Supply connection with shut-off valve

C2

=

Pressure switch to be connected to the brake actuator of the towed vehicle, to operate at 75 per cent of the asymptotic pressure in the brake actuator CF

CF

=

Brake cylinder

M

=

Pressure gauge

PP

=

Pressure test connection

TA

=

Coupling head, supply line

VRU

=

Emergency relay valve

Appendix 2 Examples of hydraulic simulators

1. Towed vehicle simulator

1.1. Supplementary line towed vehicle simulator

TA

=

coupling head, supplementary line (female coupling ISO 16028:2006)

M

=

pressure test port

PT

=

pressure transducer

P1

=

flexible pipe acc. to EN853:2007 with internal diameter 12,5 mm

A

=

hydraulic accumulator (volume: 1 000 cm³, pre-charge pressure: 1 000 kPa)

B

=

bleeding screw

V

=

bleeding device

O

=

orifice

P2

=

flexible pipe with internal diameter 10 mm

T

=

return to tractor tank

1.2. Control line towed vehicle simulator

TA

=

coupling head, control line (female coupling ISO 5676:1983)

M

=

port for pressure gauge or pressure transducer

FP

=

flexible pipe acc. to EN853:2007 with internal diameter 10 mm

RP

=

rigid pipe with internal diameter 10 mm

PT

=

pressure transducer

B

=

bleeding screw

C

=

cylinder/s (*)

2. Tractor simulator

F

=

filters

PM

=

pump

PT

=

pressure transducers

CLRV

=

control line relief valve

SLRV

=

supplementary line relief valve

SV

=

3 way solenoid valve

FR

=

flow regulator

MV

=

proportional modulation valve

TA

=

coupling head, supplementary line (male coupling ISO 16028:2006)

TC

=

coupling head, control line (male coupling ISO 5676:1983)

EC

=

electrical connection (female ISO 7638:2003)