Abstract: This invention provides an arrangement for selectively varying the illumination level of an interior light source in a vehicle. The arrangement includes supplying a current to at least one interior light source to achieve a predetermined level of illumination, and reducing the level of illumination via a shunt arrangement in response to detection of a nighttime condition.

Abstract: A switch monitoring system for measuring closure time of a switch in a vehicle when the vehicle ignition switch is off. The switch monitoring system includes an application specific integrated circuit, a low powered stand-by voltage source, and external interface circuitry connected to the switch, The switch monitoring system uses very little current to operate the time base and switches off completely after switch closure has been captured, thus preventing excessive battery drain. The microprocessor software can obtain the time to closure at the next vehicle power-up sequence.

Abstract: An automotive heater, ventilation and air conditioning (HVAC) control system reduces overall system cost and improves system reliability by reducing the number of wire interconnects between the climate control head and the multifunction body control module. Wire reduction from as many as seven to as few as one is possible with the inventive resistively multiplex system. The inventive system combines rear defrost, airconditioning on/off and a set of mode door drive motor select signals within a single climate control head. The inventive climate control head includes a series of resistors and switches that effectively allow a vehicle user to select the various modes of HVAG system operation. The climate control head effectively combines the various possible mode signals into one analog signal that varies according to the selected mode. The single analog signal is fed into a single analog-to-digital port in the multifunction control module.

Abstract: A system for preventing fogging in air conditioning systems is disclosed. The system employs a strategy whereby if fogging conditions are present, the temperature of the evaporator is stepped downwardly in increments which allow the surface of the evaporator to stabilize thereby eliminating localized cold spots.

Abstract: A method and firmware motor control and fault operation system for positioning motors of a Heater-Ventilation-Air Conditioner Unit in response to request of chosen comfort levels in the interior of a motor vehicle. The positioning being accomplished by moving the shafts of the motors in a direction and for a period of time determined from mathematical computations. The system controls motor shaft movement of motors arranged to operate as hybrid closed and open loop motor control systems and all motor shaft movement performed with respect to purely time period measurements.

Abstract: A microprocessor based temperature determination system for displaying outside ambient temperature inside of an automotive vehicle. The system utilizes sensors for vehicle speed, engine temperature and exterior temperature measurements in order to accurately determine a true temperature indication, taking into account non-ambient heat sources. The temperature displayed to the vehicle's occupants is either the current reading from the exterior temperature sensor, or is an averaged temperature value. The averaged temperature value is determined by averaging the value of the temperature sensor's readings over a ten second interval, taking a sample every one half second.

Abstract: A lighting control system with self calibration for employing the entire physical travelling range of a dimmer switch. A lookup table and linear interpolation are used in conjunction with the voltage output of the dimmer switch in order to identify the appropriate duty cycle of a Pulse Width Modulated signal which drives the lamps in the system. Two of the values in the lookup table are default minimum and maximum values of voltage which can be expected from a worst case switch device. The system dynamically determines and stores any new maximum or minimum voltage which is received from the dimmer switch. These dynamically determined minimum and maximum values are used to replace the default values in the lookup table thus calibrating the lookup table. The calibrated lookup will take into account the operating parameters of the actual switch in the vehicle and will therefore always produce a corresponding change in illumination intensity over the entire physical range of the dimmer switch.

Abstract: A method and firmware motor calibration system for measuring average system voltage of operating electric motors and time of movement between physical stops of mechanical structures coupled to the output shafts of the electric motors. The system calibrates motors arranged to operate as hybrid closed and open loop motor control systems. Data concerning position of the shafts is determined for the closed loop motor control systems.

Abstract: A method and software/firmware fixed capacity compressor control system for varying the set point temperature of a evaporator in response to changes in ambient temperature in order to produce optimum cooling in the passenger compartment of a vehicle while preventing frost from accumulating on the fins of the evaporator. The system includes an evaporator probe and an outside ambient sensor and firmware for computing set-point steady state temperatures values over a wide range of ambient temperature. Also circuits are provided for cycling ON and OFF a fixed capacity compressor in a manner to achieve optimum cooling in the passenger compartment of the vehicle in response to the computed evaporator set point temperatures.