Commission Delegated Regulation (EU) 2015/68 of 15 October 2014 supplementing Regulation (EU) No 167/2013 of the European Parliament and of the Council with regard to vehicle braking requirements for the approval of agricultural and forestry vehicles (Text with EEA relevance) (c. 68)

ANNEX III U.K. Requirements applying to the measurement of the response time

5. Towed vehicles equipped with hydraulic braking systems U.K.

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

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). U.K.

5.3. The tractor simulator shall have the following characteristics: U.K.

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 U.K.

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. U.K.

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.