Abstract: A rear suspension controller for controlling the suspension characteristic of a vehicle having a suspension which supports a vehicle body on plural wheels, wherein the acceleration of the vertical movement of at least one of the front wheels is measured and a corresponding signal is produced for detecting sporadic irregularities on a road surface. This acceleration signal is compared against preset reference signals and the characteristic of the rear suspension is altered, e.g., the suspension is made harder or softer, in dependence on the comparison in order to keep the controllability and stability or to maintain a good ride comfort according to demand. Additionally, the preset reference signals themselves are changed depending upon the vehicle speed because the influence of the shock caused by the irregularities changes according to the vehicle speed.

Abstract: When a single shock due to a bump or dip in a road surface is detected at the front wheel of a vehicle running on the road, the characteristic of the air suspensions is immediately altered to improve comfort of ride thereof. For that purpose, a distance between the body of the vehicle and the front wheel is detected and when the distance exceeds a predetermined value, the suspension characteristic is altered to a softer state by communicating the air chambers of the front and the rear air suspensions. Further, the pressures of the air chambers are detected and, in case the pressure difference is greater than predetermined value, the communicating operation is prohibited in order to prevent an abrupt change of the vehicle posture.

Abstract: According to the present invention, as soon as the sporadic protrusion or sinking of a road surface is detected at the front wheel of the vehicle during its running on the road surface, the air chambers of the air suspensions for the right and the left rear wheels of the vehicle are connected to each other to alter the spring constant of the rear suspensions to `soft` when the rear wheel passes over the sporadic protrusion or sinking of the road surface, so that the feel of ride of the vehicle and the controllability and stability thereof are kept good. After the rear wheel moves over the sporadic protrusion or sinking, the characteristic of the rear suspensions is returned to the original state appropriate to the normal running state of the vehicle. Detectors for the sporadic protrusion or sinking of the road surface may be provided for the right and the left front wheels of the vehicle, respectively. The rear suspensions of the vehicle can be more appropriately controlled by that.

Abstract: A rod actuator which includes a d.c. motor, a reduction gearing, a solenoid assembly which is used to define an intermediate stop position, and rotation stops. The angular extent through which an output shaft of the reduction gearing is rotatable is limited by a pair of limit stops. The solenoid assembly includes a plunger which is located intermediate the limit stops. A rotational stop is rotatably mounted on the output shaft and has a projection which is adapted to abut against the plunger to cease the motion of the rotational stop. The rotational stop is mounted on the output shaft so as to be rotatable relative thereto through a small angle by a lost motion, but is driven for integral rotation with the output shaft when such angle is exceeded. A lost motion connector is used so the angles of rotation where the rotation of the output shaft is stopped by the plunger during its clockwise and counter-clockwise rotations will be substantially equal.

Abstract: A new rear suspension controller is invented for improving a ride comfort or for improving controllability and stability when a vehicle passes a sporadic bump or dip of otherwise smooth road surface. It includes: a front vehicle height detector which measures a distance between the vehicle body and a front wheel; a first judgment means which detects a sporadic bump or dip by comparing the signal from the front vehicle height detector with a preset standard value; a rear vehicle height detector which measures a distance between the vehicle body and a rear wheel; a second judgment means which detects the bump or dip that the front wheel has passed; and a rear suspension characteristic alteration means which alters, for example, a spring constant of air suspensions, a dumping force of shock absorbers, stabilizer compliance, etc. when the first judgment means detected the bump or dip and returns the characteristic after the second judgment means judges that the rear wheel has passed it.

Abstract: In an antiskid control system, the acceleration of a vehicle wheel is detected and compared with a predetermined value. A first count value is incremented in response to the detection of the wheel acceleration exceeding the predetermined value. When this first count value exceeds a reference count within a first preset period, the road is interpreted as having a rough surface and a second count value is similarly incremented in response to the detection of the wheel acceleration exceeding the predetermined count. If the second count value does not reach the reference count within a second preset period longer than the first preset period, the road is interpreted as having a smooth surface. The gradient of brake hydraulic pressure of the vehicle is controlled in response to the different interpretation of the road surface.

Abstract: A suspension controller for controlling the suspension characteristic of a vehicle having a suspension which supports a vehicle body on plural wheels, wherein the distance between the vehicle body and at least one of the wheels is measured and a corresponding signal indicating the height of the vehicle is produced. This height signal is compared against preset reference signals and the characteristic of the suspension is altered, e.g., the suspension is made harder or softer, in dependance on the comparison. Additionally, the preset reference signals themselves are changed depending upon the alteration in the characteristic of the suspension. Changing the reference signals eliminates influence of the change in the amplitude of vibration of the height of the vehicle as a result of altering of the suspension characterisitc, whereby exact detection of a change in the amplitude of the vibration due to irregularities of the road surface is enabled to prevent overcontrol and hunting.

Abstract: A pulse signal is generated by a wheel speed sensor with a frequency proportional to the speed of rotation of a vehicle wheel, the pulse signal comprising a plurality of frames each having a series of a predetermined number of pulses which are tended to be affected by noise and pulse mutilation. Pulses in each frame are counted and from the count is derived an instantaneous wheel speed value. The difference between the successively derived instantaneous speed values is taken and compared with a predetermined threshold. A first or a second indication is given in response to the difference being lower or higher than the threshold, respectively. If the first indication is given, output signals representing the average wheel speed and average wheel acceleration of the wheel are derived from the instantaneous speed values of successive frames.

Abstract: This invention relates to a rear height controller for a vehicle having a height adjuster between the body and a rear wheel. The controller includes a front height detector which detects a sporadic bump or dip of a road surface on which the vehicle is running by measuring the distance between the body and a front wheel. The front height data is sent to a bump or dip judgment section in which the height data from the right and the left height detectors is judged whether the data corresponds to a predetermined size of bump or dip. If the data is judged to correspond to a bump or dip of a predetermined size, the judgment section sends a signal to a rear height adjuster. If the right front wheel sinks into a dip, the left rear body height is lowered in order to keep the posture of the vehicle unchanged when the right rear wheel sinks into the dip. If the right front wheel rides onto a bump, the left rear body height is raised.

Abstract: In an antiskid control system for the hydraulic braking system of a wheeled vehicle, the rotational speed of a vehicle wheel and the acceleration of the wheel are detected and levels of road surface friction are determined on the basis of the wheel speed and acceleration to give a first indication that the road has a high value of friction or a second indication that the road has a low value of friction. The wheel speed and acceleration are analyzed to detect a down-pressure mode to decrease the fluid pressure of the braking system and an up-pressure mode to increase the pressure. In response to the presence of the first indication, the down-pressure mode is effected at a lower rate and then at a higher rate. In response to the occurrence of the second indication, the down-pressure mode is effected at the higher rate.

Abstract: In an antiskid control system for a motor vehicle, the speed and acceleration of at least one vehicle wheel are detected, and from the detected wheel speed, the speed of the vehicle is estimated. First and second variable threshold values are derived from the vehicle speed. The wheel speed and acceleration are compared with the first and second thresholds, respectively, to estimate the level of road surface friction and to operate solenoid-operated hydraulic brake pressure decreasing means. The operating period of the pressure decreasing means is controlled in accordance with the estimated road surface friction to prevent excessive reduction of the brake pressure and premature locking of the wheels.

Abstract: In an antiskid control system the speed of a vehicle wheel is compared with a variable threshold which is a function of the speed of the vehicle and a first comparator output is generated when the speed is lower than the variable reference. The acceleration of the wheel is compared with a predetermined threshold for generating a second comparator output when the acceleration is lower than the threshold or a third comparator output when the acceleration is higher than the threshold. The fluid pressure of the braking system is lowered in response to there being a simultaneous presence of the first and second comparator outputs and raised in response to there being a simultaneous presence of the first and third comparator outputs.

Abstract: When a sporadic shock due to a protrusion or dip of a road surface is detected at front wheels of a vehicle during its cruising on the road surface, the characteristic of the rear wheel suspension of the vehicle is altered immediately or just before the rear wheels pass it to improve the controllability and the stability of the vehicle or the smooth feeling of the ride. For that purpose, a rear suspension controller is invented which includes a height sensor for detecting the distance between the body of the vehicle and each of the right and left front wheels thereof, height data calculator which generates a plurality of height data from the front vehicle height, a judgment section which compares each of the height data with a respective reference value that is predetermined corresponding to each height datum and generates comparisons and a rear suspension characteristic alteration devices which alter the spring constant, damping force, etc. of the rear suspensions.

Abstract: Present invention relates to an apparatus to improve the riding feel of the vehicle when the rear wheels pass over a sporadic hollows or protrusions of a ground by altering the rear suspension characteristic, i.e. the spring constant and the damping force of the shock absorbers after such hollows or protrusions are detected by front wheels of the vehicle passing thereover and the detected hollow or protrusion is judged to exceed a predetermined size. Besides that, the present invention has another control measures to give a priority to the maintenance of the vehicle posture when the driving condition is that need drivability and stability more than the riding comfort over the above-mentioned rear suspension characteristic alteration.

Abstract: In an antiskid control system, first and second wheel speed values are derived from pulse signals supplied from wheel speed sensors to indicate respectively the rotational speeds of first and second wheels of the vehicle. A trimming value is derived from the difference between the first and second wheel speed values and used as a multiplier by which the first wheel speed value is multiplied to compensate for the deviation of the speed of the first wheel with respect to the speed of the second wheel. The compensated first wheel speed value compared with a variable threshold that is a function of the speed of the vehicle to determine the down pressure timing.

Abstract: When a load to an engine of a vehicle running at a constant speed increases and a vehicle speed slows down below a preset vehicle speed for a constant speed running condition, a gear of an automatic transmission is shifted down. A shift-down signal for causing the gear to shift down is held for a predetermined time to prevent the shift-up of the gear in cases when the vehicle speed momentarily recovers the preset vehicle speed.

Abstract: A fluid pressure control device for an automatic transmission of an automotive vehicle, wherein throttle pressure and governor pressure control valves produce a throttle pressure and a governor pressure from a line pressure, while several shift valves produce selectively, according to the balance of the throttle pressure and the governor pressure, pressures for actuating several friction engaging devices which provide several speed stages of the transmission. However, the shift valve which controls switching between the highest and the next to the highest speed stages is electrically controlled in its kick down throttle opening and high speed region, so that in this region the upshift and the downshift lines are both largely biased to the higher vehicle speed, depending upon a throttle opening sensor, a vehicle speed sensor, and an electrical computing device.

Abstract: Speed pulses having a frequency proportional to an actual rotational speed V of a rotary shaft are generated. A period T of time which is necessary for generating a predetermined number of the speed pulses is measured, and then the difference .DELTA.T between the measured time T and a predetermined time to which is equal to the measured time T when the rotary shaft rotates at a desired speed V.sub.o is calculated. A number N of the speed pulses generated within a predetermined period of time is measured. Thereafter, the calculated difference .DELTA.T, the measured number N and a predetermined number N.sub.o which is equal to the measured number N when the rotary shaft rotates at the desired speed V.sub.o are multiplied by each other to obtain a value .DELTA.V which corresponds to the difference between the actual speed V and the desired speed V.sub.o. Then, in response to the calculated value .DELTA.V, the rotational speed of the rotary shaft is controlled to reduce the above-mentioned difference to zero.

Abstract: A hydraulic control system for an automatic transmission including a fluid coupling type torque converter, and a gear system provided with two or more frictional devices adapted to establish two or more speed conditions.

Abstract: An electric control circuit for a safety apparatus of an automotive vehicle comprises an electrically operated actuator connected in series with an electric power source through a normally open switch to actuate the safety apparatus upon closure of the switch and is provided with a storage condenser connected in parallel with the switch and actuator to supply electric energy to the actuator upon disconnection of a conductor between the power source and actuator. In the control circuit, a first diode is connected at its anode in series with the positive electrode of the power source and at its cathode in series with the positive electrode of the condenser to interrupt an electric current discharged from the condenser therethrough, and a second diode is connected at its cathode in series with the negative electrode of the power source and at its anode in series with the negative electrode of the condenser to interrupt a reverse electric current flowing therethrough.