US 7,111,704 B2Granted

Hydrostatic drive apparatus for a road vehicle

AssigneeJohnson Welded Products, Inc.

InventorTruman G. Johnson

Life of this patent

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Abstract

A road vehicle utilizes hydraulic machines for primary and accessory vehicle drive functions. An internal combustion engine directly drives a first variable capacity hydraulic machine selectively operable as pump or motor, an electric machine electrically coupled to a storage battery is selectively operable as motor or generator and is mechanically coupled to a second hydraulic machine operable as pump or motor, and at least one hydraulic drive motor is coupled to a vehicle drive wheel. A controller regulates the capacity of the first hydraulic machine, and controls the functionality of the first and second hydraulic machines to selectively crank the engine or charge the storage battery. The first hydraulic machine also supplies hydraulic fluid to accessory drive motors including a power steering drive motor, an air compressor drive motor and a supercharger drive motor.

Claims8

Dependent claims

Hydrostatic drive apparatus for a road vehicle, comprising in combination:

an internal combustion engine;
a hydrostatic drive including a first hydraulic machine selectively operated as a pump or a motor and mechanically coupled to said engine, at least one hydraulic drive motor fluidically coupled to said first hydraulic machine and mechanically coupled to a drive wheel of said vehicle to propel said vehicle when said first hydraulic machine is operated as a pump;
an electric machine;
a storage battery electrically coupled to said electric machine;
a second hydraulic machine selectively operated as a pump or a motor, mechanically coupled to said electric machine and fluidically coupled to said first hydraulic machine;
and
a controller effective (1) during a cranking mode of operation to operate said first and second hydraulic machines as motor and pump, respectively, so that said electric machine is driven by said storage battery to supply fluid from said second hydraulic machine to said first hydraulic machine to crank said internal combustion engine, and (2) during a run mode of operation to operate said first and second hydraulic machines as pump and motor, respectively, so that fluid is supplied from said first hydraulic machine to said second hydraulic machine for mechanically driving said electric machine to generate charging current for said storage battery.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/768,249Filed 30 Jan 2004
Published: US 2005/0167178 A14 Aug 2005
Granted: 26 Sep 2006
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

B60K 6/12
Prime-movers comprising combustion engines and mechanical or fluid energy storing means: by means of a chargeable fluidic accumulator
B60K 17/10
Characterised by arrangement, location or kind of gearing: of fluid gearing
B60K 2006/126
By means of a chargeable fluidic accumulator: the hydraulic accumulator starts the engine
B60K 2006/268
Characterised by the motors or the generators: electric drive motor starts the engine, i.e. used as starter motor