GB1595736A

GB1595736A - Automotive drive system

Info

Publication number: GB1595736A
Application number: GB4766/78A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1977-02-07
Filing date: 1978-02-07
Publication date: 1981-08-19
Also published as: AU3305578A; JPS6235928B2; AU513553B2; JPS53124830A; BR7800725A; CA1080128A; ZA78748B; DE2805049A1

Description

(54) IMPROVED AUTOMOTIVE DRIVE SYSTEM (71) 1, VINCENT EARL CARMAN, a Citizen of the United States, of 9512, S.W.

47th Ave., Portland, Oregon, 97219, United States of America do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to an improved automotive drive system and has for an object thereof the provision of a new and improved automotive drive system.

According to the present invention there is provided a wheeled vehicle having an engine and a drive system comprising: (a) an accumulator for storing pressurised fluids; (b) a reservoir for storing fluid; (c) power transmission means mechanically coupled to at least one wheel of said vehicle for driving and being driven by said wheel; (d) transmission control means for selectively hydraulically connecting said power transmission means to said reservoir and to said accumulator for causing the power transmission means to pump hydraulic fluid from said reservoir into said accumulator for storage therein under pressure in response to the driving of said power transmission means by said wheel to brake said vehicle; and for selectively connecting said power transmission means to said reservoir and to said accumulator for receiving hydraulic fluid under pressure from the accumulator to drive said wheel; (e) engine driven pump means hydraulically coupled to said engine and connected to said reservoir and to said accumulator for pumping fluid from said reservoir into said accumulator for storage therein under pressure when driven by said engine; (f) pressure responsive means connected to said accumulator and to said engine, which means is adapted to cause said engine to be stopped when the pressure in said accumulator exceeds a predetermined maximum, and is adapted to cause said engine to be started in response to a drop in the pressure in said accumulator below a predetermined minimum.

In a preferred embodiment starting control means is arranged to enable pressurised hydraulic fluid from said accumulator to be utilised to drive said engine for starting, and arranged to prevent the application of back pressure from said accumulator on said engine driven pump means, said pressure responsive means being connected to said starting control means for actuating said starting control means; cut off means is connected to said engine and to said starting control means for stopping the utilisation of hydraulic fluid from said accumulator for driving the engine when said engine has reached a predetermined operational state; and the engine driven pump means is adapted to serve as motor means for utilising hydraulic power for driving the engine.

Also, the engine driven pump means is in the form of a hydraulic motor-pump for either driving and thereby starting said engine or being driven by said engine to pump fluid; said motor-pump having an inlet and an outlet; first valve means connected to the inlet of said motor-pump and to said accumulator for controlling fluid flow therebetween; second valve means connected to the outlet of said motor-pump and to said accumulator for controlling fluid flow therebetween; third valve means connected to the inlet of said motor-pump and to said reservoir for controlling fluid flow therebetween; fourth valve means connected to the outlet of said motor-pump and to said reservoir for controlling fluid flow therebetween; and starting control means responsive to said pressure responsive means for selectively operating at least said first and fourth valve means to permit fluid to flow either from said accumulator through said motor-pump to said reservoir whereby said motor-pump operates as a motor to drive said engine, or from said reservoir through said motor-pump to said accumulator whereby said motor-pump operates as a pump driven by said engine to pressurise said accumulator: and said first and fourth valve means each comprise solenoid-operated valves, and said starting control means comprises electrical circuit means for operating said solenoid-operated valves. The power transmission means is preferably a fixed displacement hydraulic pump motor, and said transmission control means comprises a first control valve connected to said accumulator and to an inlet of said pump-motor, a second control valve connected to an outlet of said pump-motor and to said reservoir, a third control valve connected to said reservoir and to said inlet of said pump-motor, a fourth control valve connected to said outlet of said pump-motor and to said accumulator; and said transmission control means is arranged to selectively actuate said first, second, third and fourth control valves.

The invention will be described further, by way of example, with reference to the accompanying drawings, wherein: Figure 1 is a schematic view of an automotive drive system forming one embodiment of the invention, showing an engine driven pump thereof being used as a starter motor, and showing a vehicle drive motor in a neutral condition; Figure 2 is a schematic view showing the automotive drive system of Figure 1 in a forward drive condition with the pump connected as a pump; Figure 3 is a schematic view showing the automotive drive system of Figure 1 in a reverse drive condition with the pump connected as a pump; and Figure 4 is a schematic view showing the automotive drive system of Figure 1 in a braking condition with the pump connected as a pump.

An improved automotive drive system forming one specific embodiment of the invention includes a prime mover in the form of an internal combustion engine 10, which is arranged to operate at its most efficient engine speed. Usually, this speed is slightly over one-half the maximum rated RPM. When the vehicle speed reaches approximately one-half the maximum speed of the vehicle, or extra rapid acceleration is needed, the engine 10 can be caused to operate at a higher speed determined by the position of a foot throttle (not shown). The engine has a drive shaft 12 mechanically connected to a motor-pump in the form of a fixed displacement hydraulic pump 14 which also can operate as a fixed displacement hydraulic motor. The engine has an ignition circuit 16 activated when a key operated switch 18 and contacts 20 of a pressure responsive switch 22 are closed to connect it to a battery 24. Contacts 26 of the swith 22 are connected in series with normally closed contacts 28 which are opened, when the engine reaches a minimum operated speed, by a known speed responsive device 30 driven by the engine.

The fixed displacement pump 14 also serves as a fixed displacement motor to rotate the engine 10 to start the engine. To start the engine, switches 18, 82 and 120 are closed by the driver, the system being in its neutral condition as is shown in Figure 1.

The contacts 28 are closed since the engine is not running so that starting control solenoids 34 and 35 are energised to open control valves 36 and 37. It being assumed that pressure on hydraulic liquid 38 in an accumulator 40 is lower than the desired minimum operating pressure of, for example, 1700 pounds per square inch. The switch 22 is set to energise whenever the pressure drops below a predetermined level, for example, 2,000 PSI, contacts 26 close and current flows through closed contacts 28 and opens valves 36 and 37 by energising solenoids 34 and 35. The liquid flows from the accumulator 40 through lines 42 44 46 48 and 50, the valve 36 and lines 52 and 54 to port 56 of the pump 14, through the pump 14 (to drive it as a motor), out port 58 of the pump, through lines 60 and 62 of the valve 37 and lines 64, 66, 68 and 70 to a reservoir 72. This drives the pump as a motor to turn the engine to start it. When it has started and reached a low level operating speed, the speed responsive device opens the switch 28 to cut off the drive to the engine by de-energising the solenoids 34 and 35 so that the valves 36 and 37 close.

The pump 14 now acts as a pump to pump the liquid from the line 54 through the lines 60 and 74, a check valve 76 and line 78 to the line 48. Power transmission means, which in this embodiment comprises a pump-motor in the form of a fixed displacement hydraulic motor 100 which serves as the vehicle drive motor and also may operate as a pump, may or may not be turning depending on whether or not the vehicle is in motion when the engine start cycle occurs. If we assume that the vehicle is moving forward, and motor 100 and control valves 128 and 90 are both open, the motor will be in a neutral condition and oil from reservoir 72 will flow through valve 128, motor 100 and valve 90 back to the reservoir 72.

To drive the automobile forward, the driver closes switch 80 preferably placing the system in the condition shown in Figure 2, and opens switch 120. Closing the switch 80 causes energisation of transmission control solenoid 84. Opening switch 120 deenergises transmission control solenoid 124.

Thus, control valve 88 opens and control valve 128 closes. The liquid 38 then is forced from the line 42 or 46 through line 92, the control valve 88, lines 94 and 96; port 98 of motor 100; the motor 100; port 102 of the motor 100; lines 104 and 106; the control valve 90, and line 108 to the line 66 leading to the pump through a line 107 if the engine is running. If the engine is not running, the oil will flow through line 66 to the reservoir 72, a check valve 109 and lines 111 and 54. The motor is connected to drive axle 110 and drives drive wheels 112 of the automobile in a forward direction.

To drive the automobile in reverse, the driver places the system in the condition thereof shown in Figure 3 by actuating a switch in the driving compartment and depressing the accelerator. The switches 80 and 82 are open and switches 120 and 122 are closed to energise transmission control solenoids 124 and 126 to open control valves 128 and 130. The liquid 38 pumped from the pump 14 or flow from accumulator 40, then flows from the line 46 through line 140, the control valve 130, lines 142 and 102, the motor 100, lines 96 and 144, the control valve 128 and line 146.

To brake the automobile, the system is placed by the driver in the condition shown m Figure 4, by removing his foot from the accelerator. The switch 120 is closed to cause the control valve 128 to open. The motor 100 then acts as a pump to pump the liquid 38 from the line 146 through the control valve 128, lines 144 and 96; the motor 100; lines 104 and 150; check valve 152 and lines 154, 44 and 42 to the accumulator 40.

To start the engine 10 under a condition in which there is insufficient pressure in the accumulator 40 to start the engine, the driver closes the switch 18 to open the control valves 36 and 37 and closes the switch 120. The automobile then is pushed, or coasted downhill, and the motor 100 is in its pumping phase (braking) and pumps the liquid 38 through the valve 152 to the accumulator and the pump 14, which is thereby driven as a motor to turn over the engine and start it. Also, a hand operated auxiliary pump (not shown) could be used to pump oil from the reservoir into the accumulator.

An adjustable relief valve 160 is provided to prevent the pressure in the accumulator from exceeding a predetermined maximum, for example, 3,200 pounds per square inch.

The pressure switch 22 is set to be closed to start the engine 10 whenever the pressure is less than a desired predetermined minimum, for example, 1,700 pounds per square inch.

The switch 22 is set to o en the contacts 20 and 26 when the upper limit of the desired operating ranges, for example, 2,800 pounds per square inch. The motor 100 then is driven by the accumulator 40 alone, without the engine 10, until the pressure goes below a lower limit of, for example, 1,700 pounds per square inch, the switch 22 then closing the contacts 20 and 26.

For starting, using the pump as a starter motor, the engine 10 is turned over very rapidly as the starter motor is capable of providing as much horsepower as the engine. This rapid starting of the engine eliminates pollutants during the frequent stop/start cycle of the engine.

WHAT I CLAIM IS: 1. A wheeled vehicle having an engine and a drive system comprising: (a) an accumulator for storing pressurised fluids; (b) a reservoir for storing fluids; (c) power transmission means mechani caly coupled to at least one wheel of said vehicle for driving and being driven by said wheel; (d) transmission control means for selectively hydraulically connecting said power transmission means to said reservoir and to said accumulator for causing the power transmission means to pump hydraulic fluid from said reservoir into said accumulator for storage therein under pressure in response to the driving of said power transmission means by said wheel to brake said vehicle; and for selectively connecting said power transmission means to said reservoir and to said accumulator for receiving hydraulic fluid under pressure from the accumulator to drive said wheel; (e) engine driven pump means hydraulically coupled to said reservoir and to said accumulator for pumping fluid from said reservoir into said accumulator for storage therein under pressure when driven by said engine; (f) pressure responsive means connected to said accumulator and to said engine, which means is adapted to cause said engine to be stopped when the pressure in said accumulator exceeds a predetermined maximum, and is adapted to cause said engine to be started in response to a drop in the pressure in said accumulator below a predetermined minimum.

2. A vehicle as claimed in claim 1 comprising starting control means arranged to enable pressurised hydraulic fluid from said accumulator to be utilised to drive said engine for starting, and arranged to prevent the application of back pressure from said accumulator on said engine driven pump means, said pressure responsive means being connected to said starting control means for actuating said starting control means.

3. A vehicle as claimed in claim 2 further comprising starter cut off means connected to said engine and to said starting control means for stopping the utilisation of hydraulic fluid from said accumulator for driving the engine when said engine has reached a predetermined operational state.

4. A vehicle as claimed in claim 3, wherein the starter cut off means comprises

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. the control valve 90, and line 108 to the line 66 leading to the pump through a line 107 if the engine is running. If the engine is not running, the oil will flow through line 66 to the reservoir 72, a check valve 109 and lines 111 and 54. The motor is connected to drive axle 110 and drives drive wheels 112 of the automobile in a forward direction. To drive the automobile in reverse, the driver places the system in the condition thereof shown in Figure 3 by actuating a switch in the driving compartment and depressing the accelerator. The switches 80 and 82 are open and switches 120 and 122 are closed to energise transmission control solenoids 124 and 126 to open control valves 128 and 130. The liquid 38 pumped from the pump 14 or flow from accumulator 40, then flows from the line 46 through line 140, the control valve 130, lines 142 and 102, the motor 100, lines 96 and 144, the control valve 128 and line 146. To brake the automobile, the system is placed by the driver in the condition shown m Figure 4, by removing his foot from the accelerator. The switch 120 is closed to cause the control valve 128 to open. The motor 100 then acts as a pump to pump the liquid 38 from the line 146 through the control valve 128, lines 144 and 96; the motor 100; lines 104 and 150; check valve 152 and lines 154, 44 and 42 to the accumulator 40. To start the engine 10 under a condition in which there is insufficient pressure in the accumulator 40 to start the engine, the driver closes the switch 18 to open the control valves 36 and 37 and closes the switch 120. The automobile then is pushed, or coasted downhill, and the motor 100 is in its pumping phase (braking) and pumps the liquid 38 through the valve 152 to the accumulator and the pump 14, which is thereby driven as a motor to turn over the engine and start it. Also, a hand operated auxiliary pump (not shown) could be used to pump oil from the reservoir into the accumulator. An adjustable relief valve 160 is provided to prevent the pressure in the accumulator from exceeding a predetermined maximum, for example, 3,200 pounds per square inch. The pressure switch 22 is set to be closed to start the engine 10 whenever the pressure is less than a desired predetermined minimum, for example, 1,700 pounds per square inch. The switch 22 is set to o en the contacts 20 and 26 when the upper limit of the desired operating ranges, for example, 2,800 pounds per square inch. The motor 100 then is driven by the accumulator 40 alone, without the engine 10, until the pressure goes below a lower limit of, for example, 1,700 pounds per square inch, the switch 22 then closing the contacts 20 and 26. For starting, using the pump as a starter motor, the engine 10 is turned over very rapidly as the starter motor is capable of providing as much horsepower as the engine. This rapid starting of the engine eliminates pollutants during the frequent stop/start cycle of the engine. WHAT I CLAIM IS:

1. A wheeled vehicle having an engine and a drive system comprising: (a) an accumulator for storing pressurised fluids; (b) a reservoir for storing fluids; (c) power transmission means mechani caly coupled to at least one wheel of said vehicle for driving and being driven by said wheel; (d) transmission control means for selectively hydraulically connecting said power transmission means to said reservoir and to said accumulator for causing the power transmission means to pump hydraulic fluid from said reservoir into said accumulator for storage therein under pressure in response to the driving of said power transmission means by said wheel to brake said vehicle; and for selectively connecting said power transmission means to said reservoir and to said accumulator for receiving hydraulic fluid under pressure from the accumulator to drive said wheel; (e) engine driven pump means hydraulically coupled to said reservoir and to said accumulator for pumping fluid from said reservoir into said accumulator for storage therein under pressure when driven by said engine; (f) pressure responsive means connected to said accumulator and to said engine, which means is adapted to cause said engine to be stopped when the pressure in said accumulator exceeds a predetermined maximum, and is adapted to cause said engine to be started in response to a drop in the pressure in said accumulator below a predetermined minimum.

4. A vehicle as claimed in claim 3, wherein the starter cut off means comprises

speed responsive means connected to said engine for determining the speed of rotation thereof, so that said starter cut off means is actuated when the engine reaches a predetermined minimum speed.

5. A vehicle as claimed in claim 2, 3 or 4, wherein the engine driven pump means is adapted to serve as motor means for utilising hydraulic power for driving the engine.

6. A vehicle as claimed in claim 1, incorporating hydraulic motor means arranged to drive to said engine for starting said engine; starting control means for supplying hydraulic fluid from said accumulator to said motor means to drive said engine.

7. A vehicle as claimed in any preceding claim wherein said engine includes an ignition system and said pressure responsive means is arranged to disable said Ignition system if the pressure in said accumulator exceeds said predetermined maximum.

8. A vehicle as claimed in any one of claims 1 to 6, wherein said engine includes an ignition system and said pressure response sive means is arranged to turn on said Ignition system if the pressure in said accumulator is below said predetermined minimum.

9. A vehicle as claimed in claim 1, wherein the engine driven pump means is in the form of a hydraulic motor-pump for either driving and thereby starting said engine or being driven by said engine to pump fluid, said motor-pump having an inlet and an outlet; first valve means connected to the inlet of said motor-pump and to said accumulator for controlling fluid flow therebetween; second valve means connected to the outlet of said motor-pump and to said accumulator for controlling fluid flow therebetween; third valve means connected to the inlet of said motor-pump and to said reservoir for controlling fluid flow therebetween; fourth valve means connected to the outlet of said motor sump and to said reservoir for controlling fluid flow therebetween; and starting control means responsive to said pressure responsive means for selectively operating at least said first and fourth valve means to permit fluid to flow either from said accumulator through said motor-pump to said reservoir whereby said motor-pump operates as a motor to drive said engine, or from said reservoir through said motor-pump to said accumulator whereby said motor-pump operates as a pump driven by said engine to pressurise sai accumulator.

10. A vehicle as claimed in claim 9, wherein said first and fourth valve means each comprise solenoid-operated valves, and said starting control means comprises electrical circuit means for operating said solenoid-operated valves.

11. A vehicle as claimed in any preceding claim, wherein the engine driven pump means is of fixed displacement.

12. A vehicle as claimed in any preceding claim, wherein said power transmission means is a fixed displacement hydraulic pump-motor.

13. A vehicle as claimed in claim 12, wherein said transmission control means comprises a first control valve connected to said accumulator and to an inlet of said pump-motor, a second control valve connected to an outlet of said pump-motor and to said reservoir, a third control valve connected to said reservoir and to said inlet of said pump-motor, a fourth control valve connected to said outlet of said pump-motor and to said accumulator; and wherein said transmission control means is arranged to selectively actuate said first, second, third and fourth control valves.

14. A vehicle as claimed in claim 13, wherein said first, second, third and fourth control valves are each solenoid-operated and said transmission control means includes an electrical circuit for actuating said control valves.

15. A vehicle as claimed in claim 13 or 14, further comprising a check valve connected to said outlet of said pump-motor and to said accumulator to permit fluid to flow from said pump-motor through said check valve to said accumulator but to prevent fluid flow through said check valve in the opposite direction.

16. A vehicle as claimed in any one of claims 1 to 11, wherein said power transmission means incorporates fixed displacement pump means having an inlet and an outlet selectively connectable to said accumulator and said reservoir by said transmission control means, to provide forward and reverse drive for said wheel and a neutral condition wherein fluid is drawn from and returned to the reservoir when said wheel is rotated.

17. A vehicle as claimed in any preceding claim, including an auxiliary pump for pressurising said accumulator.

18. A vehicle substantially as hereinbefore described with reference to the accompanying drawings.