Hybrid hydraulic-electric engine

Abstract

An automobile drive engine is described having an electric motor with two hydraulic pumps fixedly mounted on the center shaft of the motor. The smaller sized hydraulic pump is mounted on one side of the electric motor and the larger pump is mounted on the other side of the electric motor. The two hydraulic pumps are connected by hydraulic hoses which allow hydraulic fluid to circulate between the two pumps. As the electric motor begins to turn, it causes the impeller blades of the larger hydraulic pump to rotate forcing hydraulic fluid through the hose thereby building pressure on the impeller blades of the smaller hydraulic pump. The smaller hydraulic pump then begins to rotate. Because of the ratio of sizes, the smaller hydraulic pump begins to rotate much faster increasing the torque and/or speed produced by the electric motor.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

Not Applicable

STATEMENT REGUARDING FEDERALLY SPONSERED RESEARCH OR DEVELOPMENT

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REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISC APPENDIX

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BACKGROUND OF THE INVENTION

This invention relates to a hybrid hydraulic-electric engine and in particular to an electric drive engine whose torque characteristics and/or speed are varied by hydraulic pumps mounted on the drive shaft of the electric engine.

Over the years, many gearing configurations have been proposed to modify the torque and/or speed characteristics of electric motors. For example, U.S. Pat. No. 6,726,588 describes a differential electric engine wherein the rotational torque of the output drive shafts of the engine is controlled by first and second differential stages coupled to the shafts. This configuration is a mechanical gear control of the motor output as compared to the hybrid control system of this invention.

U.S. Pat. No. 5,492,189 discloses a propulsion system having first and second drive shafts connected to a steady state internal combustion engine and a transitionally operating driving system. The combination engine and driving system are mounted on different shafts of a planetary gear to permit continuous variations of the output speed, independent of the applied torque.

In U.S. Pat. No. 6,662,905, an elevator control is described which uses the counterweight as a hydraulic plunger to assist in moving the car upward and downward. The counterweight plunger supplements a fluid circulation circuit comprising at least a driving pump coupled to valves. The fluid control does not adjust the speed of the lift motor, other than by varying the load placed on the motor.

BRIEF SUMMARY OF THE INVENTION

The present invention comprises a hybrid hydraulic-electric motor having a central shaft which is driven by the motor. A forward positioned hydraulic pump and a rearward positioned hydraulic pump are fixedly mounted on the central shaft and are interconnected by hydraulic hoses which permit fluid to circulate between the two hydraulic pumps. As the electric motor turns, it rotates impellers within the forward hydraulic pump thereby applying a rotational force to the rearward hydraulic pump to augment the torque of the electric motor.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a hybrid hydraulic-electric engine in accordance with this invention.

FIG. 2 is a graphical illustration of the relationship between torque and EMF applied to a standard electric engine.

FIG. 3 is a graphical illustration of the relationship between torque and EMF of a hybrid hydraulic-electric engine in accordance with this invention.

FIG. 4 is a flow chart showing force flow in the hybrid hydraulic-electric engine of this invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring more particularly to FIG. 1, an electric motor 10 is fixedly mounted on a central shaft 11 and is powered by a battery 12 through starting switch 13. A forward hydraulic pump 14 is mounted on one side of shaft 11 and contains a plurality of impeller blades 15 which are rotated by shaft 11 upon energization of electric motor 10. Rotating impeller blades 15 pump hydraulic fluid from forward hydraulic pump 14 through hydraulic hose 16 to apply hydraulic pressure on impeller blades 17 of rearward hydraulic pump 18. Impeller blades 17 are fixedly mounted on shaft 11 and the hydraulic pressure on impeller blades 17 augments the torque produced by electric motor 10 on shaft 11. A second hydraulic hose 19 returns hydraulic fluid from rearward pump 18 to forward hydraulic pump 14. Central shaft 11 is particularly adapted to power a load such as an automobile (not shown) requiring a large torque upon energization of electric motor 10. For optimum performance, a power ratio between forward hydraulic pump 14 and rearward hydraulic pump 18 should be at least 10-1.

FIG. 2 shows the torque produced by a standard electric motor without the hydraulic assist of this invention as an electromagnetic force (EMF) is applied to the coils of the motor. The torque produced on the motor shaft varies in a substantially linear fashion with the magnitude of the applied EMF. As shown in FIG. 3, the hybrid hydraulic-electric engine shown in FIG. 1 initially has a relatively slower increasing torque due to the additional load placed on the motor by forward hydraulic pump 14. The turning of impeller blades 15 in forward hydraulic pump 14 forces hydraulic fluid into rearward hydraulic pump 18 to supplement the torque on shaft 11. With a hydraulic ratio of at least 10-1 the output torque on central shaft 11 increases parabalicly to produce a high torque within a short period following energization of motor 10. The force flow in hybrid hydraulic-electric engine 10 is shown in the flow diagram of FIG. 4.

Claims

1) A hybrid hydraulic-electric engine comprising

An electric motor,

A central shaft driven by said electric motor,

A first hydraulic pump fixedly mounted on said central shaft adjacent one side of said electric motor,

Said first hydraulic pump having a plurality of impeller blades to pump fluid within said pump through an outward orifice of said pump,

A second hydraulic pump mounted on said central shaft on the side of said electric motor remote from the first hydraulic pump,

Fluid conveyor means for transporting hydraulic fluid from said first hydraulic pump to said second hydraulic pump and

Second fluid conveying means for transporting hydraulic fluid from said second hydraulic pump to said first hydraulic pump.

2) A hybrid hydraulic-electric engine pump according to claim 1 wherein the power ratio between the first and second hydraulic pumps is at least 10-1.

3) A hybrid hydraulic-electric hybrid engine according to claim 2 wherein the central shaft rotates the wheels of an automobile.