WO1994007028A1

WO1994007028A1 - Drive unit

Info

Publication number: WO1994007028A1
Application number: PCT/GB1993/001991
Authority: WO
Inventors: John Linton-Raeburn
Original assignee: Linton Raeburn John
Priority date: 1992-09-22
Filing date: 1993-09-22
Publication date: 1994-03-31
Also published as: AU4827793A

Abstract

A drive unit comprises a piston (11, 13, 15, 17) arranged to execute motion within a cylinder (3, 5, 7, 9). This defines a pressure chamber (19, 21, 23, 25) bounded by part of an internal wall of the cylinder and a face (35, 37, 39, 41) of the piston. The piston is connected to a drive shaft (59) and pressurised liquid supply means (87) causes pressurised liquid into the pressure chamber to cause the motion of the piston.

Description

DRIVE UNI T

The present invention relates to a drive unit, e. g. for producing motive power or generating electricity. However, possible motive power applications of such a drive unit are not limited to vehicles but may be any where mechanical power, especially with high torque, is required, such as in lifting equipment.

US-A-4, 106 391 describes a drive unit which uses pressurised liquid as an energy source. However, a new and highly advantageous drive unit using pressurised liquid has now been devised.

Thus, the present invention provides a drive unit comprising a piston arranged to execute motion within a cylinder and defining a pressure chamber bounded by part of an internal wall of said cylinder and a face of said piston, said piston being connected to a drive shaft, and pressurised liquid supply means for introducing pressurised liquid into said pressure chamber to cause said motion of the piston.

The drive unit may utilise any liquid, for example, hydraulic fluid. However, in many preferred embodiments the liquid will be water. Preferably, the pressurised liquid supply means incorporates pumping means for operating the piston (or pistons), especially pumping means which comprises a pressure intensifier. The pumping means may be electrically operable, eg. using an electrical power source according to the first aspect of the invention.

However, any pressurised water source may be used for example a reservoir or river dam or waves, e.g. in a lake or sea. In the latter case, a semi-submerged pipe or other hollow structure may be used for harnessing the wave pressure. Specifically, the upward surge of sea swell provides the water pressure necessary for powering the drive unit.

The drive unit may be based on a conventional reciprocating internal combustion engine. In an especially preferred variant, the piston(s) is/are arranged to reciprocate within one or more respective elongate cylinders, to drive a conventional camshaft via one or more respective connecting rods. Alternatively, the unit may be a hydraulic analogue of a rotary ( ankel-type) engine with a rotor or rotors.

The present invention will now be explained in more detail by the following non-limiting description of a preferred embodiment and with reference to the accompanying drawings in which: -

Figures 1A and IB show a drive unit of a first embodiment according to the present invention.

Figure 2 shows a drive unit of a second embodiment of the invention; and

Figure 3 shows fluid flow paths within the manifold of the unit shown in Figure 2.

< The unit shown in Figures 1A and IB is essentially similar to an internal combustion engine. It comprises an engine block 101 with cylinders 103, 105 etc. Standard connecting rods 107, 109 etc co-operate with a camshaft 111.

The cylinders contain hydraulic rams 113, 115 etc. each comprising a respective piston slidable within a respective cylinder and which pistons actuate the connecting rods. The hydraulic rams are driven by an electrically powered pumped water supply with pressure boosted to around 400-800 bar (6, 000-1200pεi ). This is produced using a pressure intensifier (not shown) which provides an approximately δO-fold boost in pressure. This traction unit is especially suited to providing a relatively slow (low rpm)/high torque drive. Although it can be used in a vehicle it, could be used in other applications, eg. for a lifting device.

Figure 2 shows a second embodiment in which a drive unit 1 comprises four elongate cylinders 3, 5, 7, 9 provided with respective pistons 11, 13, 15, 17 slidable therein. Each cylinder has a respective pressure chamber 19, 21, 23, 25 above respective upper faces 27, 29, 31, 33 of the pistons 11, 13, 15, 17.

The ends of the pistons which are remote from their upper faces are pivotally attached to respective connecting rods 35, 37, 39, 41. At the end of each connecting rod remote from its piston, a respective bearing 43, 45, 47, 49 cooperates with a camshaft 51 forming part of a drive shaft 53.

One end 55 of the drive shaft 53 is connected to a gearbox 57 and the other end 59 is connected to a flywheel 61. An output shaft 63 of the gearbox is connected to a generator 65 for generating electricity.

Each piston is provided with a respective pair of injection pipes 67, 69; 71, 73; 75, 77; 79, 81 respectively connecting each pressure chamber and lower region thereof with a fluid distribution manifold 83.

A water supply pipe 85 supplies water to the manifold via, first a pressure intensifier 87, and second, a water accumulator 89 for smoothing out pressure variations in the pressurised water supply.

Figure 3 shows the fluid flow arrangement within the manifold 83. As well as the water supply pipe 85, the manifold is provided with a water outlet pipe 91. The arrows in this Figure show the liquid flow direction (one-way or two-way) in the manner of conventional hydraulics terminology. The injection pipes 67, 69; 71, 73; 75, 77; 79,81 are connected to the inlet 85 via respective single non-return valves 121, 123; 125, 127; 129, 131; 133, 135.

Between the latter valves and the cylinders 3, 5, 7, 9, the pairs of injection pipes are bridged by respective bridging conduits 137, 139, 141, 143 in the middle of which are respective double non-return valves 145, 147, 149, 151. The outlets double non-return valves are connected to the outlet pipe 91 via respective outlet channels 153, 157, 159, 161.

This drive unit, including its respective pistons, cylinders, camshaft and valves operates in an analogous manner to a four-stroke internal combustion engine but with the pressurised water providing the motive force for the pistons instead of explosion of an air/fuel mixture in the conventional case.

In the light of this disclosure, modifications of the described embodiments as well as other embodiments, all within the scope of the appended claims will now be apparent to persons skilled in the art.

Claims

1. A drive unit comprising a piston arranged to execute motion within a cylinder and defining a pressure chamber bounded by part of an internal wall of said cylinder and a face of said piston, said piston being connected to a drive shaft, and pressurised liquid supply means for introducing pressurised liquid into said pressure chamber to cause said motion of the piston.

2. A drive unit according to claim 1, wherein said cylinder is elongate and said cylinder is arranged to effect reciprocating motion therein, an upper face of the piston bounding the combustion chamber, and wherein a connecting rod joins a side of the piston remote from the upper face to said drive shaft which is provided with a cam surface.

3. A drive unit according to claim 1, wherein said piston is in the form of a rotor arranged to effect rotary motion within the cylinder.

4. A drive unit according to any preceding claim, comprising one or more further cylinders with respective further pistons therein, each defining a respective further pressure chamber.

5. A drive unit according to any preceding claim, wherein the or each pressure chamber is connected to the pressurised liquid supply means via inlet valve means.

6. A drive unit according to any preceding claim, wherein the or each pressure chamber is provided with liquid outlet means.

7. A drive unit according to claim 6, wherein said liquid outlet means is provided with outlet valve means.

8. A drive unit according to any preceding cl.aim, wherein said pressurised liquid supply means comprises pumping means.

9. A drive unit according to claim 8, wherein the pumping comprises a pressure intensifier.

10. A drive unit according to claim 8 or claim 9, wherein the pumping means is arranged to be electrically powered by an inverter for producing an alternating current output from a direct current voltage source.

11. A drive unit according to any preceding claim , wherein the pressurised liquid supply means comprises means for utilising sea swell to produce pressurised water.

12. A vehicle comprising a drive unit according to any preceding claim.

13. An electrical generator comprising a drive unit according to any preceding claim.