Abstract: A trailer electrical monitor function is implemented into a microprocessor based truck tractor and trailer electrical communication system where a programmable memory unit connected to a trailer electronic control unit is used by the trailer electronic control unit to store a trailer identification code, the result of which is connected through an interface circuit to the trailer electronic control unit where the result is then transmitted to a tractor electronic control unit and/or to an external programming unit. The tractor and trailer electronic control units control the state of a plurality of switching devices to establish the appropriate electrical connection into and out of a standard seven pin tractor/trailer electrical connector where high speed data communication links are used for control diagnostics.

Abstract: A truck tractor and trailer electrical communication system having one electronic control unit located in tractor and another electronic control unit located in at least one trailer both respectively controlling the state of a plurality of switching devices to establish the appropriate electrical connection into and out of a standard seven pin tractor/trailer electrical connector where high speed data communication links are used for control and diagnostics.

Abstract: A solenoid driver applies an actuation current to a solenoid for a predetermined period and a lower holding current thereafter. A switching device pulses the applied current within upper and lower limits to maintain the actuation and holding current amplitudes, the pulses being integrated by solenoid inductance into a substantially steady-state current. A multiprocessing unit determines the amplitudes of solenoid current. A signal representative of desired current amplitudes is compared with a signal representative of measured solenoid current, and a signal representative of the difference therebetween is used to control the switching device. Voltage developed across a resistor in series with the solenoid is input to a differential amplifier having connected to its output a peak detector that mimics the decay rate of current in the solenoid, the signal representative of measured solenoid current being obtained from the peak detector.

Abstract: An electro-mechanical shifter (80) for use with a hydraulic transmission (62) of the type employing a clutch and having first and second valve members (C, D) that in the same and opposite open and closed conditions provide at least one range of gear ratios for driving an output member such as an engine drive shaft (64). Shifter (80) includes a control arm (9) positionable by an operator along a frame (10) that includes a pin (24) operated by an actuator (32) which extends into an arcuate cam opening (22) in frame (10) operative to prevent arm (9) from being moved from a highest gear ratio of a first range of gear ratios beyond a lowest gear ratio of a second range of gear ratios without disengagement of the clutch.

Abstract: An improved control system for an automatic change gear transmission (10) driven by a throttle (18) controlled engine (12) is provided. The control system includes a processing unit (30) for receiving inputs indicating at least throttle position (18), engine speed (20) and vehicle speed (28) and for processing these inputs in accordance with a program to determine the correct engaged gear ratio and for issuing command signals to a transmission shifting mechanism (26). The processing unit includes of operator actuated selection means (32) for selecting a mode of operation (D.sub.1 or D.sub.L) wherein vehicle performance is maximized and the control will evaluate and execute allowable skip downshifts.

Abstract: An automatic clutch control system for controlling a vehicle master clutch (14) drivingly interposed a throttle controlled engine (12) and a change gear transmission (10) having a clutch protection portion (70) to prevent the clutch from destructively overheating due to excessive slipping is provided. The clutch protection portion (70) includes a device for maintaining a variable parameter simulating clutch operating temperature (110) and devices (104 and 116) for causing said variable parameter to be increased and decreased, respectively, at first and second rates selected to simulate clutch heating and cooling rates, respectively. A signal generating device (126) is responsive to the simulated value exceeding a predetermined limit to generate a clutch protection output singal (84) effective to cause the clutch to be operated in a non-slipping, preferably fully engaged, mode of operation.

Abstract: Disclosed is an automatic control system for a powershift, preselect transmission (10) including a plurality of power paths (36, 38) alternately connectable between input (12) and output (20) shafts by first engaging selected ones of synchronizer clutches (42, 74, 84) associated with each of a plurality speed ratio gears (44, 46, 76, 78, 80) in each path and then alternately engaging a powershift clutch (48, 82) associated with each path. The control system includes a hydraulic logic system (118) which may be electronic and a hydraulic and shift valve system which may be electrically controlled should the logic be electronic. The control system preselects ratio gears in a nondriving path and then alternately engages the powershift clutches to switch driving connections from one path to the other. The logic system includes an improved reverse sequence valve (132) and improved shift valves (124, 126, 128).

Abstract: A vehicle monitor (10) apparatus for monitoring vehicles (14) in a monitoring location (17). A vehicle unit (12) mountable in a vehicle includes circuitry (21) for transmitting, on a continuous repetitive basis, information characterizing the vehicle and unique thereto. In addition, a monitoring unit (16) mountable at the monitoring location includes circuitry (33) for receiving information transmitted by the vehicle unit. Such monitoring circuitry includes an infrared light receiver (29) and a preamplifier with ambient light compensation circuitry (100) connected thereacross.

Abstract: A system for optimizing the number of cylinders operating in a multicylinder engine, during ongoing engine operation. Input circuitry monitors conditions under which the engine is operating and generates corresponding input signals. Logic circuitry, based on such input signals, determines whether to then add to, subtract from, or maintain unchanged the number of cylinders operating in the engine. Output circuitry, responsive to the logic circuitry, enables and disables specific cylinders in the engine, in a preferred embodiment through valve selectors respectively provided on several cylinders of the multicylinder engine. The logic technique includes a bidirectional counting portion capable of sequential up and down counting through several steps to correspondingly sequentially enable or disable the valve selector equipped cylinders of the engine in, preferably, one cylinder steps.