US 5,397,991 A · Multi-battery charging system for reduced fuel consumption and emissions in automotive vehicles

Abstract

A multi-battery charging system for reduced fuel consumption and emissions for an automotive vehicle. The system starts the vehicle with a start battery in a fuel saving manner, removing electrical torque from the alternator shaft, and allows a second (run) battery to provide all or some of the current required by the vehicle loads as a fuel savings measure. The start battery is recharged after start and switched out of the system fully charged for future vehicle starts. The run battery is recharged when its charge level drops below a predetermined level with an on board battery charging device powered from a 115 volt or 220 volt ac power line source external to the vehicle. The system also increases the alternator field current to charge the run battery during vehicle deceleration to use vehicle momentum to torque the alternator shaft, thus saving fuel. The system controls the alternator field current with a voltage regulator. The voltage regulator senses the charge level of the run and start batteries and vehicle operating conditions and provides the proper current into the alternator rotor for maximum fuel savings. The voltage regulator may be a non-microprocessor or a microprocessor controlled device.

Claims34

Dependent claims

A battery charging system for an automotive vehicle having electrical accessory circuits and a starter motor for starting a fuel consuming engine comprising:

a start battery for providing a discharge current for operating the starter motor;
a run battery for operating the accessory circuits;
a first device for monitoring the state of charge of the start battery;
a second device for monitoring the state of charge of the run battery;
an alternator having a variable output condition including a regulated output voltage at a selectable level and an output current, said alternator being driven by the engine;
a first circuit for electrically connecting the alternator output to the start battery for charging the start battery;
a second circuit for electrically connecting the alternator output to the run battery for charging the run battery;
and
a control circuit for selecting and controlling the output condition of the alternator in response to the sensed states of charge of the start battery and the run battery, such that a first alternator output voltage level is normally selected when the sensed state of charge of the start battery is at or above a first preselected charge level and the sensed state of charge of the run battery is at or above a second preselected charge level, and the alternator produces less counter torque on the engine when the first alternator output voltage level is selected relative to the counter torque produced at other times when a second output voltage level, greater than the first output voltage level, is selected.

6 more elements

A method for operating a battery charging system for an automotive vehicle having electrical accessory circuits and a starter motor for starting a fuel consuming engine comprising:

providing a start battery having a discharge current for operating the starter motor;
providing a run battery for operating accessory circuits;
monitoring the state of charge of the start battery;
monitoring the state of charge of the run battery;
providing an alternator having a variable output condition including a regulated output voltage at a selectable level and an output current, said alternator being driven by the engine;
controlling the output of the alternator in response to the sensed states of charge of the start battery and the run battery, and normally producing a first alternator output voltage level when the sensed state of charge of the start battery is at or above a first preselected charge level and the sensed state of charge of the run battery is at or above a second preselected charge level, such that the alternator generates less counter torque on the engine when the first alternator output voltage level is produced relative to the counter torque generated at other times when a second output voltage level, greater than the first output voltage level, is produced;
connecting the alternator output to the start battery for charging the start battery;
and
connecting the alternator output to the run battery for charging the run battery.

6 more elements

Dependencies are inferred from the claim text.

Multi-battery charging system for reduced fuel consumption and emissions in automotive vehicles

Life of this patent

Multi-battery charging system for reduced fuel consumption and emissions in automotive vehicles

Life of this patent

Abstract

Claims34