摘要:
An electronic braking system which recognizes differential braking across an axle. A stored adaptive capability is provided whereby a braking controller is able to learn the braking imbalance and correct for this by introducing differential pressure adjustments such as increasing braking at the wheel of the lower brake output and/or reducing braking at the wheel with a higher brake output. The learning process is completed over selected parts of several vehicle stops and is repeated continuously.
摘要:
A sensor is associated with each suspension unit for adjusting the ride height of a vehicle, and each sensor gives an output that varies progressively with ride height. A control circuit, preferably microprocessor based, is arranged to(i) read each of the outputs at least once, preferably in sequence,(ii) select the output which corresponds to the sensed ride height that differs most from the desired ride height, and(iii) apply a correction to the suspension unit associated with the selected output to adjust it towards the desired ride height.The control circuit repeats (i) to (iii) until all the sensed ride heights are within acceptable limits of the desired height whereupon the system enters a so-called trim mode. In this mode corrections are based on a calculated ride height at a conceptual center of height where height variations due to pitch and roll are minimal.
摘要:
A system is disclosed for monitoring operation of a speed sensor which produces a pulse signal with a repetition frequency related to the speed being sensed.An analogue speed signal is derived from a pulse signal having a repetition frequency related to the sensed speed and is fed to an integrator which, under the control of the pulse signal, performs successive separate integrating operations on the analogue speed signal in the periods between successive pulses, and a comparator compares the integrated sum thus produced with a reference value corresponding to a limit for normal generation of pulses, to produce a warning signal if the integrated sum exceeds the reference value. The system may include a timer to respond to successive warning signals and produce a malfunction signal if they occur with less than a predetermined time interval between them. The system may also include a differentiator to differentiate the sensor pulse signal so as to obtain a spiked reset pulse at each edge of each sensor pulse, these reset pulses then being used to control the integrator. The integrating operations may be performed during the mark and the space portions of each pulse cycle.
摘要:
An electronic braking system for trailers. A control system is incorporated into the braking equipment of a towing vehicle to provide a trailer braking command signal. This signal is regulated so as to balance the braking between the towing vehicle and the trailer through the assessment of forces in the coupling between the two vehicles. The assessment is made indirectly and is calculated from forces measured in the suspension components of at least two axles of the towing vehicle and the changes occurring therein during braking.
摘要:
An electronic braking system for a vehicle having foundation brakes (137, 138) and a vehicle retarder (129), wherein an electrical braking demand signal (D) is generated from a single brake pedal and wherein the retarder (129) is operated variably or in small steps as the brake pedal movement is increased from a zero or rest position up to a partial point in its movement range which is calculated to give substantially maximum retarder powder based on the total mass of the vehicle. As a result, for a fully loaded condition this partial point occurs at low pedal deflection and, in an unloaded condition where a given retarder will produce a higher deceleration, this point occurs at a higher pedal deflection, wherein in both cases pushing the pedal beyond the calculated partial point causes foundation braking to be commenced to supplement the retarder torque.
摘要:
A trailer braking system for a towing vehicle has a trailer braking valve (26) is fed with a pressurized air supply which is modulated by the opening of the valve, as controlled by a first control pressure regulated by a trailer braking controller (24) in accordance with braking demand signals, to produce a trailer braking pressure. In order that a trailer braking pressure may be generated even if the above trailer braking valve control fails, the valve is supplied with a second control pressure independently of the first, and which is also capable of operating the trailer braking valve (26). In a preferred embodiment, the second control pressure is supplied from a braking line of the towing vehicle, such that the "back up" control pressure is a function of the towing vehicle braking.
摘要:
A vehicle dual wheel braking system of the type in which a respective electronically controlled pressure adjustment channel is provided for each of the wheels at the opposite ends of an axle of the vehicle for setting the braking pressures individually for each wheel in dependence upon a common electrical signal representative of the braking demand level set by a driver of the vehicle, each channel comprising a pressure control loop containing a pressure controller, a pressure control valve which adjusts the supply of fluid from a reservoir to the brake actuators for applying and releasing the brakes by solenoid control of the inlet and exhaust functions of the pressure control valve, and a feedback transducer which supplies a signal representative of the pressure in the pressure control valve. The system includes respective fault monitoring device for detecting the presence of faults in the signals provided by the two feedback transducers, and a device responsive to the fault monitoring device such that if a feedback signal fault is detected in one of the two channels, the individual pressure control on that channel is disabled and the solenoids controlling inlet and exhaust functions of the pressure control valve of that channel are energized from an alternative mechanism of control which does not rely upon the output signal from the faulty feedback transducer.
摘要:
A vehicle braking system of the electronically compensated type in which driver demand signals to inner closed loop pressure systems for the front and rear brakes are adjusted in accordance with load signals obtained from load sensors associated with front and rear axles of the vehicle respectively, these load signals themselves being modified to take account of the weight transfer effect from the rear axle to the front axle during braking. Weight transfer is calculated from the expression: ##EQU1## the deceleration, gross vehicle weight, height of the center of gravity of the vehicle and the vehicle wheel base being calculated and stored and manipulated electronically to provide dynamic load apportioning between the various inner closed loop pressure systems controlling the front and rear brakes, respectively.
摘要:
A vehicle anti-lock brake control system includes wheel speed sensors which input speed signals to a microprocessor via an interface circuit. The microprocessor is programmed to calculate the deceleration of each wheel, compare this with a threshold and output a signal to a brake release device (A,B,C) for as long as the deceleration exceeds the threshold. The threshold level is calculated by the microprocessor as a function of the time elapsed since the threshold deceleration is exceeded. Initially the threshold is relatively low, but rises with time elapsed. After a predetermined time interval the threshold falls to a new relatively low level which depends on the slip of the wheel. If the slip of the wheel remains higher than a set level following re-application of the brake, a low "fast re-trigger" threshold level is established so as to release the brakes again rapidly if excessive deceleration is again detected.
摘要:
An inductive displacement transducer is described in which the magnitude of the phase difference between A.C. current and voltage in a coil is dependent upon the axial displacement of a monitored object. The phase difference depends upon the axial position relative to the coil of a short-circuit turn which moves with the monitored object. A magnetic flux concentrator, which may be combined with the short circuit turn, enhances the flux linkage between the short-circuit turn and the coil. In order to sense the height of a vehicle suspension strut, the coil is mounted on a plastics dirt shield, the short-circuit turn is provided by a sleeve plated with an electrically conductive metal and secured to the strut cylinder. Various circuits are described for monitoring the height signals produced by the different suspension struts of a vehicle.