WO1991010814A1

WO1991010814A1 - Rotary valves

Info

Publication number: WO1991010814A1
Application number: PCT/GB1990/002005
Authority: WO
Inventors: Nicholas Turville Bullivant
Original assignee: Nicholas Turville Bullivant
Priority date: 1990-01-06
Filing date: 1990-12-21
Publication date: 1991-07-25
Also published as: GB9000306D0

Abstract

A rotary valve comprises a valve body defining inlet, exhaust and admission ports (12, 14, 16) radially spaced about, and opening into, a bore (20) having an axis, and an outer rotary valve member (22) rotatable within the bore (20) about the bore axis. The valve further comprises an inner rotary valve member (40) rotatable within the outer valve member (22) about the bore axis, and drive coupling means to cause rotation of the valve members (22, 40) within the valve body (10) between a first position in which the valve members (22, 40) define a first passage placing the inlet port (12) in fluid communication with the admission port (16), and a second position in which the valve members (22, 40) define a second passage placing the exhaust port (14) in fluid communication with the admission port (16).

Description

"Rotary Valves"

This invention relates to rotary valves and in particular, but not exclusively, to rotary valves for an internal combustion engine.

The idea of providing a three-way rotary valve to control the inlet and exhaust flow to an internal combustion engine has been known for many years. The rotary valve has many advantages over conventional poppet valves, not least in increasing the maximum inlet/outlet cross-section and in avoiding poppet valve "bounce" at high speeds. Earlier proposals for a rotary valve have generally taken the form of a three-way tap valve consisting of a valve body and a single rotary valve element. However these earlier proposals suffer from severe disadvantages which arise because the rotary valve elements serve three functions, namely a bearing function, a sealing function, and a flow diverting function.

It is an object of the invention to provide a rotary valve which overcomes at least some of the problems associated with the earlier proposals.

According to the present invention, there is provided a rotary valve comprising a valve body defining inlet, exhaust and admission ports radially spaced about, and opening into, a bore having an axis, an outer rotary valve member rotatable within the bore about the bore axis, an inner rotary valve member rotatable within the outer valve member about the bore axis, and drive coupling means to cause rotation of the valve members within the valve body between a first position in which the valve members define a first passage placing the inlet port in fluid communication with the admission port and a second position in which the valve members define a second passage placing the exhaust port in fluid communication with the admission port

Preferably the drive coupling means is adapted to rotate the inner and outer valve members in opposite directions.

Conveniently the outer valve member is in the form of a cylindrical sleeve having a circular cross- section and provided with at least one aperture in its outer wall through which each of the ports may be placed in fluid communication with the inside of the sleeve.

Furthermore it is convenient if the inner valve member is in the form of a deflecting rotor shaped to define on one part thereof a first deflection surface which forms part of the first passage formed when the valve members are in said first position, and on another part thereof a second deflection surface which forms part of the second passage formed when the valve members are in said second position.

Advantageously the inner valve member is supported for rotation within the outer valve member by two sets of bearings each of which is spaced axially fro the ports which are located intermediate the two sets of bearings. Also it is preferred that the outer valve member is supported for rotation within the bore by two sets of bearings each of which is spaced axially from the ports which are located intermediate the two sets of bearings.

It is further preferred that the admission port is provided with a seal which seats against the outer valve member with a force which is dependent on the ambient pressure in the vicinity of the admission port. Advantageously the valve body incorporates oil supply means for providing a flow of oil to the outer valve member within the bore for lubrication and cooling purposes.

Preferably the drive coupling means comprises respective drive gears coupled to the inner and outer valve members and a linking gear coupling the two drive gears together for rotation in unison.

The rotary valve defined above has particular utility when used in conjunction with one or more cylinders of an internal combustion engine, with the admission port forming the admission port to said cylinder, the inlet port serving to receive a combustion charge, and the exhaust port serving for exhaustion of the combustion gases. In use, the rotar valve may either be driven continuously, for example driven off the engine crankshaft, or it may be driven intermittently by suitable indexing means to configure the valve appropriately for each stroke of the engine.

Preferably the rotary valve includes heat insulation means for restricting the transfer of heat from the cylinder to the rotary valve. The insulation may take the form of a coating, e.g. of ceramic or other suitable material, applied to surfaces of the valve exposed to high temperature, such as the deflection surface which, in use, is exposed to exhaust gases.

The cylinder of the internal combustion engine may include at its upper end flow modulation means. In one form the flow modulation means may cause the combustion charge admitted during the induction stroke to swirl around the cylinder. In another form, the flow modulation means may comprise a rotor arranged to be spun by the exhaust gases as they leave the cylinder and to use the momentum gained to compress or accelerate the flow of the combustion charge during the subsequent induction stroke.

If required, instead of the inner valve member being driven with the outer valve member, it may be driven independently of the outer valve member, either in the same direction as the outer valve member or in the opposite direction to the outer valve member. In one embodiment the inner valve member may be formed as a multi-bladed fan or multi-sided deflector which is rotatable in the gas flow and may serve as the impeller of a generator or a turbo-charger. In another embodiment the inner valve member may be rotatable at an undetermined speed in relatioin to the outer valve member by gearing or by an elective motor.

The invention may be performed in various ways and two embodiments thereof will now be described by way of example, reference being made to the accompanying drawings, in which:-

Figure 1 is a part cut-away perspective view of a first embodiment of a rotary valve for an internal combustion engine; Figures 2a, 2b, 2c and 2d are cross-sections through the rotary valve of Figure 1, mid-way through the induction, compression, ignition and exhaust cycles respectively; and

Figure 3 is a cross-section through a second embodiment of rotary valve for an internal combustion engine.

Referring initially to Figures l and 2 , the first embodiment of rotary valve comprises a valve body 10 having upper and lower halves and defining an inlet port 12, an exhaust port 14 (see Figure 2) and an admission port 16 which communicates with the inside of the cylinder 18 of the engine and through which inlet and exhaust gases flow. A central bore 20 is defined in the valve body 10 and receives a generally cylindrical, coaxially rotatable sleeve member 22 which in this embodiment is provided with three apertures 24, as well as a coaxially rotatable deflector member 40 internally of the sleeve member 22.

The opposite end regions of the bore 20 house respective peripheral oil seals 26, one of which is shown in Figure 1. At one end, the sleeve member 22 is secured to an annular end plate 30 which carries a gear ring 32. The gear ring 32 meshes with an idler gear 34 which meshes with a gear ring 36 secured to a shaft 38 extending through the end plate 30 and fixed to the deflector member 40. The gearing is such that the sleeve member 22 and the deflector member 40 rotate in opposite directions at the same speed about the central axis. The shaft 38 and a similar shaft secured to the other end of the deflector member 40 are carried by bearing arrangements (not shown) in circular end plates (not shown) which fit one within each end of the sleeve member 22. Alternatively the shafts may be carried in bearing arrangements in the valve body adjacent either end of the sleeve member 22. Furthermore one or other of the shafts is driven from the crankshaft of the engine.

The deflector member 40 may include a purge passage 42 which is brought into alignment with a vent passage 44 towards the end of the induction stroke (see Figure 2a) to purge the rotary valve of combustion charge. The deflector member 40 includes two wiper seals 45 (see Figure 2a) which run against the inner periphery of the sleeve member 22. Also the deflector member 40 may include a further set of two wiper seals diametrically opposed to the first set of seals if required.

The deflector member 40 defines two deflection surfaces 46 and 47 which deflect the inlet and exhaust gases respectively. The latter deflection surface may be provided with a heat insulating coating, of ceramic material for example.

A sliding seal 48 surrounds the admission port 16 and bears against the sleeve member 22, and the seating force urging the seal 48 against the sleeve member 22 is adjusted according to the pressure in the cylinder by a pressure actuated wedge 50. The wedge end of the wedge 50 engages the seal 48 and the other end is exposed to the prevailing pressure in the cylinder by way of pressure tap bores 52. A spring 54 is provided behind each wedge 50 and the space may be packed with heat insulating material such as glass or mineral wool.

The upper half of the valve body 10 includes two lubrication pads or wells 56 (see Figure 2a) which supply oil to the sleeve member 22 for lubrication and cooling purposes. The pads or wells 56 themselves also act as heat sinks, and may contain porous material such as "Oilite" for distributing the oil. The oil may be supplied at atmospheric pressure and may be drawn off at sub-atmospheric pressure using a tapping from the inlet manifold of the engine.

Referring to Figure 2c the upper end of the cylinder 18 may be provided with a flow modulation device 58. The device 58 may be passive in the sense that it merely causes the combustion charge to swirl around the cylinder during the induction cycle, or it may take a more active role in that it extracts momentum from the exhaust gases leaving the cylinder 18 and uses this momentum to compress or accelerate the combustion charge during the subsequent induction stroke. In the latter case the device 58 may comprise a rotor suspended between jewelled bearings or the like in a cradle extending from beneath the valve body 10. The bearings should be capable of withstanding the high temperature which develop in use.

In the arrangements shown in the drawings, the lower half of the valve body 10 forms the cylinder head. The lower surfaces of the valve body may be coated with a suitable insulating coating as shown at 60 in Figure 2a.

In operation, the sleeve member 22 and the deflector member 40 rotate continuously in opposite directions at one half the engine speed. The states of the valve mid-way through the induction, compression ignition and exhaust strokes are shown in Figures 2a to 2d respectively, and it will be appreciated that, in a first position of the valve members 22 and 40 shown in Figure 2a, a passage is provided through the valve for admission of the combustion charge to the cylinder 18 with the first deflection surface 46 serving to guide the charge axially through the admission port 16, whereas, in a second position of the valve members 22 and 40 shown in Figure 2d, a passage is provided through the valve for discharge of exhaust gases from the cylinder 18 guided by the second deflection surface 47.

The sleeve member 22 and the deflector member 40 rotate about a common axis which is parallel to the crank axis of the engine. Alternatively the common axis may be perpendicular to or angled to the crank axis. The rotary valve can be used for many different cylinder configurations. For example, the valve may be used to supply fuel to a twin crank engine with the tops of the cylinders arranged to either side of rotary valve so that one rotary valve can serve two cylinders.

Alternatively, as shown in Figure 3, two rotary valves 100 and 101 may serve a single cylinder 118. In this arrangement, the valves 100 and 101 operate in unison so that both are either closed, open to the inlet manifold or open to the exhaust manifold.

In a further embodiment (not illustrated) the relative angular orientation of the sleeve member 22 and the deflector member 40 may be adjusted during operation by shifting the axis of the idler gear 34 in the direction of arrows A in Figure 1, i.e. about the common axis of the sleeve member 22 and the deflector member 40. This alters the relative phasing of the deflector member 40 and sleeve member 22. The phasing may be advanced or retarded in dependence on engine speed.

The deflector member 40 as illustrated has two cut-away parts but may include more or less cut-away parts in particular applications. As a further development, the sleeve member may serve as a timing device for the spark plug or other ignition source. In a specialised form, the sleeve member may include a "pip" or recess which cooperates with a non- electrical ignition device, such as a flint, so as to "strike" the flint at the correct instant. The flint could be disengaged as necessary by a solenoid.

Claims

1. A rotary valve comprising a valve body defining inlet, exhaust and admission ports (12, 14, 16) radially spaced about, and opening into, a bore (20) having an axis, and an outer rotary valve member (22) rotatable within the bore (20) about the bore axis, characterised in that the valve further comprises an inner rotary valve member (40) rotatable within the outer valve member (22) about the bore axis, and drive coupling means (32, 34, 36, 38) to cause rotation of the valve members (22, 40) within the valve body (10) between a first position in which the valve members (22, 40) define a first passage placing the inlet port (12) in fluid communication with the admission port (16) , and a second position in which the valve members (22, 40) define a second passage placing the exhaust port (14) in fluid communication with the admission port (16) .

2. A rotary valve according to claim 1, wherein the drive coupling means (32, 34, 36, 38) is adapted to rotate the inner and outer valve members (40, 22) in opposite directions.

3. A rotary valve according to claim 1 or 2, wherein the outer valve member (22) is in the form of a cylindrical sleeve having a circular cross-section and provided with at least one aperture (24) in its outer wall through which each of the ports (12, 14, 16) may be placed in fluid communication with the inside of the sleeve.

4. A rotary valve according to claim 1, 2 or 3, wherein the inner valve member (40) is in the form of a deflecting rotor shaped to define on one part thereof a first deflection surface which forms part of the first passage formed when the valve members are in said first position, and on another part thereof a second deflection surface which forms part of the second passage formed when the valve members are in said second position.

5. A rotary valve according to any preceding claim, wherein the inner valve member (40) is supported for rotation within the outer valve member (22) by two sets of bearings each of which is spaced axially from the ports (12, 14, 16) which are located intermediate the two sets of bearings.

6. A rotary valve according to any preceding claim, wherein the outer valve member (22) is supported for rotation within the bore (20) by two sets of bearings each of which is spaced axially from the ports (12, 14, 16) which are located intermediate the two sets of bearings.

7. A rotary valve according to any preceding claim, wherein the admission port (16) is provided with a seal (48) which seats against the outer valve member (22) with a force which is dependent on the ambient pressure in the vicinity of the admission port (16) .

8. A rotary valve according to any preceding claim, wherein the valve body (10) incorporates oil supply means (56) for providing a flow of oil to the outer valve member (22) within the bore (20) for lubrication and cooling purposes.

9. A rotary valve according to any preceding claim, wherein the drive coupling means comprises respective drive gears coupled to the inner and outer valve members (40, 22) and a linking gear coupling the two drive gears together for rotation in unison.

10. A rotary valve according to any preceding claim, wherein the inner valve member includes a purge passage (42) for alignment with a vent passage (44) in the valve body (10) to purge the valve.