Navistar International Transportation Corporation

W Thomas Irick

Merrill D Miller

Robert L Dowler

James L Roussey

Richard L Malecki

John A Sanner

Michael R Singer

A convienience feature is added to a DRL circuit to enable the driver to temporarily override the DRL system in situations where it is appropriate, such as when the vehicle is approaching weigh scales or entering a tunnel. The convenience feature is embodied in a convenience circuit that is interposed in the current feed path to the DRL circuit. The convenience circuit comprises a momentary switch that is actuated by the driver and a timing relay module that is responsive to the actuation of the momentary switch.

Daytime running lights convenience feature

A parking lamp operating system reduces the electrical load on the battery of a vehicle, such as a truck, during periods when the vehicle engine is off but the parking lamps of the vehicle remain on wherein a switched signal input from the battery is modulated to provide a pulse-width-modulated output to the gate of a power transistor having a power input from the battery and an output to the parking lamps. The pulsed signal causes the transistor to intermittently switch the power to the lamps thereby reducing the effective voltage thereto while providing sufficient light output to be observed. The modulator may be bypassed by a second signal line connected to the vehicle alternator to provide a continuous signal to the transistor gate, thereby providing full power to the lamps when the engine is running.

Parking lamp operating system

A system for alerting the operator of a vehicle to potentially damaging motoring of the engine before such motoring actually occurs so that corrective action can be taken. A speed sensor senses rotational speed of the counter/input shaft of a manual transmission and operates an indicator that presents the alert to the driver. The alert is given with the clutch disengaged as soon as the transmission is placed in a gear that causes the counter/input shaft to operate at a speed that will cause potentially damaging motoring of the engine. Because the alert is given before the clutch is re-engaged, an opportunity is given to prevent the potentially damaging motoring.

Engine overspeed sensing and readout

The electrical system of a vehicle includes a primary voltage source for starting and operating the engine of the vehicle and an auxiliary voltage source for operating the electrical accessories of the vehicle, particularly when the engine is not operating, and a voltage differential monitor circuit for warning the vehicle operator of the existence of a low voltage condition of the auxiliary battery, such as resulting from an auxiliary battery charging system failure which could result in the inability of an electrical accessory to operate even when the engine is operating. The voltage differential between the primary and auxiliary sources is measured by coupling same to a voltage comparison device, namely a pair of voltage dividing resistor pairs providing inputs to an operational amplifier in which an output is turned on when the voltage differential is above a predetermined value determined by the voltage division ratio of the resistors causing the amplifier to direct a signal to a switching device, a field effect transistor, which in turn completes a circuit to a lamp causing same to become illuminated, the illuminated lamp warning the operator of the system failure.

Auxiliary battery monitor

A daytime running light circuit is integrated with the existing headlight circuit of an automotive vehicle. The daytime running light circuit functions to automatically illuminate the headlights at reduced intensity when the vehicle is running and the headlight switch is turned off. Any time, however, that the headlight switch is turned on, the headlights are illuminated at full intensity. The daytime running light circuit comprises a day relay and a night relay. The night relay is responsive to the headlight switch being turned on for preventing operation of the daytime relay which would otherwise illuminate the headlamps at reduced intensity if the vehicle were running and the headlight switch off. When the headlight switch is off, the night relay enables the day relay to be operated whenever the vehicle is running. Indication that the vehicle is running is obtained from the alternator 'R' terminal. The alternator 'R' terminal signal may be further conditioned by sensing the status of one or more devices on the vehicle, such as the parking brakes or transmission, so that the day relay is operated by the alternator 'R' terminal voltage signal only if all these one or more other devices indicate that the vehicle is not incapable of motion.

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New Haven, IN, United States of America

W Thomas Irick