Gm Global Technolgoy Operations, Inc.

Robert J Nowakowski

Ellis G Wheadon

Van V Riesberg, Jr

Van V Reisberg, Jr

Robert P MacKenzie

An apparatus for and method of indicating when the battery in a motor vehicle is discharging is disclosed in which the battery voltage during vehicle operation is monitored and compared to a stored value representing the open-circuit voltage of the battery measured prior to the vehicle engine being cranked for starting. An indication that the battery is discharging is provided only after a discharging condition, i.e., the battery voltage is less than the stored value, is detected at each of a predetermined member of consecutive timed intervals.

Vehicle battery discharging indicator

An apparatus for and method of testing the condition of a motor vehicle cranking system is disclosed in which the voltage at the battery terminal of the cranking motor is measured at one second intervals during cranking and compared to a set of predetermined minimum values stored in a computer lookup table according to the battery temperature and engine temperature during cranking. If a measured voltage is below a corresponding minimum voltage value, an indication is provided to the operator. The predetermined set of minimum values for each combination of measured battery and engine temperatures corresponds to the minimum voltages that would be provided at the measured temperatures by a cranking system capable of providing at least the minimum voltages down to and including the lowest design temperature.

Cranking system performance indicator

A battery charging system for a dual-voltage motor vehicle electrical system that has a pair of series-connected batteries that can energize an electric cranking motor. One of the batteries is charged from a diode-rectified alternating current generator. A voltage regulator regulates the output voltage of the generator and includes a switching means connected in series with the field winding of the generator to control field current. The other battery is charged by field discharge current that is produced by the voltage induced in the generator field winding when the switching means is switched to a nonconductive state.

Dual-voltage battery charging system

A dual voltage motor vehicle electrical system comprising series connected cranking and accessory batteries that are used to energize an electric vehicle engine cranking motor. The accessory battery is charged by a vehicle engine driven generator and the cranking battery is charged by a battery charging circuit having an input connected to the accessory battery and an output connected to the cranking battery. The battery charging circuit is maintained in operation for a period of time after shut down of the engine to charge the cranking battery from the accessory battery. The battery charging circuit includes an inductance coil for transferring energy between the accessory and cranking batteries which may take the form of an actuating coil of a magnetic switch the contacts of which disconnect the accessory battery from an electrical load when the actuating coil is deenergized.

Dual voltage motor vehicle electrical system

The output voltage of an engine-driven generator is varied in accordance with engine vacuum in a manner to increase the charging rate during deceleration of the vehicle and to decrease the charging rate during acceleration of the vehicle. The charging current developed in the generator is alternately applied to one or the other of two storage batteries while the other storage battery is connected to supply power to the various electrical loads of the vehicle. A switching circuit responsive to the terminal voltage of the battery connected to supply power to the loads operates to exchange the battery connections when the voltage supplied to the loads decreases below a reference value so that the depleted battery is connected to be charged by the generator and the charged battery is connected to supply power to the loads.

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Indianapolis, IN, United States of America

Robert J Nowakowski