Motor vehicle electrical system including a combined starter/generator
First Claim
1. In a motor vehicle including an engine and a starter/generator which is adapted to crank the engine during a starting mode before the engine has been started, and to be driven by the engine for generating electric current during a generating mode after the engine has been started, a system of electrical distribution, comprising:
- a lower storage battery for supplying relatively low voltage operating current to low voltage vehicle electrical loads, and an upper storage battery operative in concert with said lower storage battery to supply relatively high voltage electrical current to said starter/generator during said starting mode and to other high voltage vehicle electrical loads;
charging control means connecting said starter/generator to the lower and upper storage batteries during said generating mode, such that the starter/generator supplies power solely to the lower battery when the engine speed is lower than a reference speed below which the output voltage of the starter/generator is limited, and to the serial combination of the upper and lower batteries when the engine speed is at least as great as said reference speed, thereby to effect battery charging in the most efficient manner; and
charge equalizing means including an energy storage inductor connected to the junction of the upper and lower batteries, and converter means effective (1) when the lower battery becomes depleted due to heavy demand from the low voltage electrical loads to transfer energy from the upper battery to the lower battery through the energy storage inductor, and (2) when the upper battery becomes depleted due to prolonged engine operation below said reference speed or heavy high voltage load demand to transfer energy form the lower battery to the upper battery through the energy storage inductor, whereby the battery states of charge are maintained substantially equal in all vehicle operating conditions.
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Accused Products
Abstract
A starter/generator in combination with a dual battery dual voltage motor vehicle electrical system and an equalization circuit for maintaining substantially equal charge on the batteries. In starting, the starter/generator is operated as an equivalent series motor from the serial combination of the two batteries to crank the engine. Upon starting, the starter/generator supplies charging current at one or the other of the system voltages, depending on the engine speed. At all times, the equalization circuit transfers energy from one battery to the other as required to maintain balanced battery voltages.
52 Citations
4 Claims
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1. In a motor vehicle including an engine and a starter/generator which is adapted to crank the engine during a starting mode before the engine has been started, and to be driven by the engine for generating electric current during a generating mode after the engine has been started, a system of electrical distribution, comprising:
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a lower storage battery for supplying relatively low voltage operating current to low voltage vehicle electrical loads, and an upper storage battery operative in concert with said lower storage battery to supply relatively high voltage electrical current to said starter/generator during said starting mode and to other high voltage vehicle electrical loads; charging control means connecting said starter/generator to the lower and upper storage batteries during said generating mode, such that the starter/generator supplies power solely to the lower battery when the engine speed is lower than a reference speed below which the output voltage of the starter/generator is limited, and to the serial combination of the upper and lower batteries when the engine speed is at least as great as said reference speed, thereby to effect battery charging in the most efficient manner; and charge equalizing means including an energy storage inductor connected to the junction of the upper and lower batteries, and converter means effective (1) when the lower battery becomes depleted due to heavy demand from the low voltage electrical loads to transfer energy from the upper battery to the lower battery through the energy storage inductor, and (2) when the upper battery becomes depleted due to prolonged engine operation below said reference speed or heavy high voltage load demand to transfer energy form the lower battery to the upper battery through the energy storage inductor, whereby the battery states of charge are maintained substantially equal in all vehicle operating conditions. - View Dependent Claims (2, 3, 4)
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Specification