Council Directive 93/14/EEC (repealed)Dangos y teitl llawn

Appendix 2 Requirements applicable to two-wheel mopeds, two-wheel motorcycles and tricycles equipped with anti-lock devices

1. GENERAL

1.1. The purpose of these provisions is to define the minimum performances for braking systems with anti-lock devices fitted to two-wheel mopeds, two-wheel motorcycles and tricycles. This does not make it compulsory to fit vehicles with an anti-lock device but if such devices are fitted to a vehicle they must meet the requirements below.

1.2. The devices known at present comprise a sensor or sensors, a controller or controllers and a modulator or modulators. Any devices of a different design will be deemed to be anti-lock devices within the meaning of this Appendix if they provide performances at least equal to those prescribed by this Appendix.

2. DEFINITIONS

For the purposes of this Appendix:

2.1. Anti-lock device

means a component of a service braking system which automatically controls the degree of slip, in the direction of rotation of the wheel(s) on one or more wheels of the vehicle during braking.

2.2. Sensor

means a component designed to identify and transmit to the controller the conditions of rotation of the wheel(s) or the dynamic conditions of the vehicle.

2.3. Controller

means a component designed to evaluate the data transmitted by the sensor(s) and to transmit a signal to the modulator.

2.4. Modulator

means a component designed to vary the braking force(s) in accordance with the signal received from the controller.

3. NATURE AND CHARACTERISTICS OF THE SYSTEM

3.1. Each controlled wheel must be such that it can bring at least its own device into operation.

3.2. Any break in the supply of electricity to the device and/or in the wiring external to the electronic controller(s) must be signalled to the driver by an optical warning signal, which must be visible even in daylight; it must be easy for the driver to check that it is in working order(1).

3.3. In the event of a failure in an anti-lock device, the braking efficiency of the laden vehicle must not be less than that prescribed for whichever is the lower of the two requirements for the vehicle defined in 2.1.2.2 or 2.1.2.3 of Appendix 1.

3.4. The operation of the device must not be affected adversely by electro-magnetic fields(2).

3.5. Anti-lock devices must maintain their performance when the brake is fully applied for the duration of any stop.

4. UTILIZATION OF ADHESION

4.1. General

4.1.1. In the case of two-wheel motorcycles and tricycles, braking systems equipped with an anti-lock device are deemed acceptable when the condition

ε ≥ 0,70

is satisfied where ε represents the adhesion utilized as defined in the addendum to this Appendix(3).

4.1.2. The coefficient of adhesion utilization ε must be measured on road surfaces with a coefficient of adhesion not exceeding 0,45 and of not less than 0,8.

4.1.3. Tests must be carried out with the vehicle unladen.

4.1.4. The test procedure to determine the coefficient of adhesion (K) and the formula for calculating the adhesion utilization (ε) are as prescribed in the addendum to this Appendix.

5. ADDITIONAL CHECKS

5.1. The following additional checks must be carried out with the vehicle unladen.

5.1.1. Any wheel controlled by an anti-lock device must not lock when the full force(4) is suddenly applied to its control device, on the two kinds, of road surface specified in 4.1.2 at initial speeds of up to 0,8 Vmax but not exceeding 80 km/h(5).

5.1.2. Where a wheel controlled by an anti-lock device passes from a high-adhesion surface or a low-adhesion surface as described in 4.1.2 with the full force(4) applied to the control device, the wheel must not lock. The running speed and the instant of applying the brakes must be so calculated that, with the anti-lock device fully cycling on the high-adhesion surface, the passage from one surface to the other is made at about 0,5 Vmax not exceeding 50 km/h.

5.1.3. Where a vehicle passes from a low-adhesion surface to a high-adhesion surface as described in 4.1.2 with the full force(4) applied to the control device, the deceleration of the vehicle must rise to the appropriate high value within a reasonable time and the vehicle must not deviate from its initial course. The running speed and the instant of applying the brakes must be so calculated that, with the anti-lock device fully cycling on the low-adhesion surface, the passage from one surface to the other occurs at about 0,5 Vmax not exceeding 50 km/h.

5.1.4. Where both independent braking devices are equipped with an anti-lock device the tests prescribed in 5.1.1, 5.1.2 and 5.1.3 must also be performed using both independent braking devices together, the stability of the vehicle being maintained at all times.

5.1.5. However, in the tests provided for in 5.1.1, 5.1.2, 5.1.3 and 5.1.4, periods of wheel locking or of extreme wheel slip are allowed provided that the stability of the vehicle is not adversely affected. Below vehicle speeds of 10 km/h wheel locking is permitted.

Addendum

1. DETERMINATION OF THE COEFFICIENT OF ADHESION (K)

1.1. The coefficient of adhesion is determined from the maximum braking rate, without wheel lock, of the vehicle with the anti-lock device(s) disconnected and braking all wheels simultaneously(6).

1.2. The braking tests are carried out by applying the brakes at an initial speed of 60 km/h (or, in the case of vehicles which are unable to reach 60 km/h, a speed of roughly 0,9 Vmax), the vehicle being unladen (apart from the test instruments and/or the necessary safety equipment). The effort exerted on the brake control must be constant throughout the tests.

1.3. A series of tests may be carried out up to the critical point reached immediately before the wheel(s) lock by varying both the front and the rear brake forces, in order to determine the maximum braking rate of the vehicle(7).

1.4. The braking rate (Z) shall be determined by reference to the time taken for the speed of the vehicle to reduce from 40 km/h to 20 km/h, using the formula

where t is measured in seconds.

Alternatively, for vehicles unable to attain 50 km/h, the braking rate is determined by reference to the time taken for the speed of the vehicle to reduce from 0,8 Vmax to 0,8 Vmax – 20 where Vmax is measured in km/h.

The maximum value of Z = K.

2. DETERMINATION OF THE ADHESION UTILIZATION (ε).

2.1. The adhesion utilized is defined as the quotient of the maximum braking rate with the anti-lock device in operation (Zmax) and the maximum braking rate with the anti-lock disconnected (Zm). Separate tests must be carried out on each wheel equipped with an anti-lock device.

2.2. Zmax is calculated on the on the basis of the average of the three tests, using the time taken for the speed of the vehicle to achieve the reductions in speed specified in 1.4.

2.3. The adhesion utilized is given by the formula

(1)

The technical service should examine the electronic controller and/or any drive system with regard to possible failure modes.

(2)

Until uniform test procedures have been agreed, the manufacturers must provide the technical services with their test procedures and results.

(3)

For two-wheel mopeds, until a minimum value for ε has been established, the measured value must be recorded in the test report.

(4)

Full force means the maximum force prescribed in Section 2.4, Appendix 1 for the category of vehicle: a higher force may be used if required to actuate the anti-lock device.

(5)

On low adhesion surfaces (≤ 0,35) the initial speed may be reduced for safety reasons: in such cases, the K value and the initial speed must be noted in the test report.

(6)

Additional requirements may have to be established in the case of vehicles equipped with combined braking systems.

(7)

As an initial step, to facilitate these preliminary tests, the maximum control force applied before the critical point may be obtained for each individual wheel.