Method and apparatus for determining vehicle brake effectiveness

A method for calculating effectiveness of a vehicle braking system in a vehicle having a brake pedal during deceleration of the vehicle, comprising:

• providing a baseline deceleration rate for the vehicle;
• providing the mass of the vehicle;
• accelerating the vehicle;
• applying pressure to the vehicle brake pedal to decelerate the vehicle;
• determining brake system pressure of the vehicle during deceleration of the vehicle;
• determining a deceleration rate of the vehicle using a low-g accelerometer;
• generating a slope adjusted deceleration rate of the vehicle to automatically compensate for the effect of road slope during deceleration of the vehicle;
• calculating the effectiveness of the vehicle braking system from data representing the baseline deceleration rate of the vehicle, the slope adjusted deceleration rate of the vehicle, the brake system pressure of the vehicle during deceleration of the vehicle, and the mass of the vehicle;
• and
• generating a signal representative of the effectiveness of the vehicle braking system.

An apparatus for calculating effectiveness of a vehicle braking system during deceleration of the vehicle, comprising:

• a computer;
• a means for inputting the mass of the vehicle to the computer;
• a means for measuring brake system pressure of the vehicle during deceleration of the vehicle and for inputting the brake system pressure to the computer;
• a means for measuring road slope during deceleration of the vehicle and for inputting the road slope to the computer, said means including a low-g accelerometer;
• a means to measuring air friction of the vehicle and engine friction of the vehicle during deceleration of the vehicle and for inputting the air friction and the engine friction to the computer;
• a means for determining predicted deceleration of the vehicle and for inputting the predicted deceleration of the vehicle to the computer;
• a means for measuring deceleration of the vehicle and for inputting the deceleration of the vehicle to the computer;
• the computer having means for calculating the effectiveness of the vehicle braking system, from data representing the deceleration of the vehicle, the road slope, the air friction of the vehicle, the engine friction of the vehicle, the brake system pressure during deceleration of the vehicle, the mass of the vehicle, and the predicted deceleration of the vehicle under comparable conditions, and generating a signal representative of the effectiveness of the vehicle braking system;
• and
• a means connected to the computer for recording and storing data.