Bench testing alone may not fully reveal actual braking capability, so a portable braking instrument is used for complementary road tests.
Procedure
Fit the contact switch to the brake pedal. Connect its cable and the acceleration-sensor cable to the host. Attach the suction-mounted sensor to the front windscreen, adjust it horizontally along the vehicle's forward longitudinal axis, and tighten its mounting screws. Enter the vehicle registration, type and loading condition in the host, which determines the corresponding assessment values. Conduct the service-brake test according to the MFDD inspection procedure.
After testing and releasing the pedal, the display shows MFDD, brake coordination time, stopping distance and initial speed, and compares them with the relevant requirements. The inspector decides whether the test is valid and whether to store the results. Results can be printed, or sent by wireless communication to the inspection-station server within the 100 m range stated in the source, where data and curves can be printed.
Precautions
- Handle the electronic acceleration sensor gently. Align its arrow with the direction of travel.
- Check pedal construction before fitting the switch: top-down hooking is suitable for large vehicles and side fitting for small vehicles. Route the cable behind the accelerator to prevent dislodging the switch when moving the foot between pedals.
- The sensor's suction surface is ordinary rubber, which hardens at low temperatures such as below 0°C. Warming it in warm water before use helps it adhere.
- The centre of a truck's front windscreen generally has lower curvature and suits sensor installation and levelling. A passenger car's more curved front windscreen may make the side window more suitable. Place soft padding beneath the sensor to reduce impact if it detaches.
- After entering test mode, accelerate to the specified initial speed. When applying emergency braking, place the transmission in neutral; otherwise the measured value may be reduced.
- Do not interrupt power after entering the registration and vehicle type, or the information will be lost. Do not press the pedal after entering ready mode; an accidental trigger displays a false result and requires re-entry of the relevant information before testing.
Luoyang Naiou Electric manufactures braking road-test systems and associated peripheral sensors. Please leave an enquiry or contact customer service for further details.