A vehicle height control system is provided. This height control system is directed to establish fluid communication between right and left suspension actuators or between front and rear suspension actuators, balancing fluid pressures in the actuators for leveling a vehicle body when height level difference between right and left wheels or between front and rear wheels is greater than a first threshold value within a given period of time after an ignition switch is turned off. The height control system then blocks the fluid communication when the height level difference lower than a second threshold value smaller than the first threshold value is maintained for a preselected period of time for preventing the fluid communication between the actuators from being blocked, and instantaneously terminating the height control when the height level difference becomes smaller than the second threshold value due to variation in vehicle load caused by passengers getting in or out of a vehicle and/or baggage loaded into or unloaded from a baggage compartment.
A start-assist system provided in a vehicle having two rear shafts, one of which is a drive axle, includes a control device having an air actuator attached to the drive axle; a level sensor for detecting loads applied to the shaft axles; an air supply source for supplying compressed air to the air actuator; a first valve disposed in an air conduit for supplying air to the air actuator; a second valve for releasing air from the air actuator; and a controller for controlling the first valve and the second valve. The a controller opens the first valve to introduce air to the air actuator when a signal from the level sensor indicates that the vehicle is stopped and is unladen, and opens the second valve to release air from the air actuator when the signal from the level sensor indicates that the vehicle is stopped and parking brake is activated.
Load leveling height control is provided for a vehicle by replacing a conventional scheduled vehicle height with a load leveling height which is sensed upon detection of the opening of at least one compartment of the vehicle. Load leveling height control raises and lowers the vehicle to maintain the load leveling height. While either a passenger compartment or a cargo compartment can be monitored, preferably both are monitored to protect the vehicle from potential damage both below and above the vehicle due to changes in vehicle height as a vehicle is loaded and/or unloaded. Any currently active leveling activity is aborted such that a load leveling height or open compartment height can be read and maintained as long as a compartment remains open or until vehicle speed reaches a predefined speed, for example 16 kilometers per hour (10 miles per hour), at which time the conventional scheduled vehicle height is once again utilized.
A method of positioning a vehicle chassis of a stationary vehicle in approximate alignment with a predetermined datum is provided. The vehicle has an axle and a fluid suspension system. The fluid suspension system includes a control device, a pressurized fluid source and an exhaust passage. The pressurized fluid source and the exhaust passage are in fluid communication with the plurality of fluid suspension members through the control device. The vehicle also includes an electronic control unit operatively associated with the control device. The method including steps of providing an alignment sensor supported on the chassis for outputting a signal indicative of the orientation of the chassis to the electronic control unit and acquiring a signal output by the alignment sensor. Another step includes comparing the signal from the alignment sensor to alignment data stored in the electronic control unit. A further step includes selectively operating the control device to permit fluid communication between one or more of the fluid suspension members and one of the pressurized fluid source and the fluid exhaust until the signal from the alignment sensor approximately corresponds to the alignment data. A system for performing the method is also discussed.
A method of positioning a vehicle chassis of a stationary vehicle in approximate alignment with a predetermined datum is provided. The vehicle has an axle and a fluid suspension system. The fluid suspension system includes a control device, a pressurized fluid source and an exhaust passage. The pressurized fluid source and the exhaust passage are in fluid communication with the plurality of fluid suspension members through the control device. The vehicle also includes an electronic control unit operatively associated with the control device. The method including steps of providing an alignment sensor supported on the chassis for outputting a signal indicative of the orientation of the chassis to the electronic control unit and acquiring a signal output by the alignment sensor. Another step includes comparing the signal from the alignment sensor to alignment data stored in the electronic control unit. A further step includes selectively operating the control device to permit fluid communication between one or more of the fluid suspension members and one of the pressurized fluid source and the fluid exhaust until the signal from the alignment sensor approximately corresponds to the alignment data. A system for performing the method is also discussed.
