GB2197275A

GB2197275A - Marine propulsion device with pneumatically assisted steering, gear change and throttle control

Info

Publication number: GB2197275A
Application number: GB08723052A
Authority: GB
Inventors: Arthur R Ferguson; Martin J Mondek; Matthew H Mondek
Original assignee: Outboard Marine Corp
Current assignee: Outboard Marine Corp
Priority date: 1986-11-10
Filing date: 1987-10-01
Publication date: 1988-05-18
Also published as: FR2606362A1; DE3734085A1; SE8704316D0; IT1211866B; IT8748512A0; SE8704316L; BE1001230A3; GB8723052D0; AU7944587A; JPS63130497A

Description

1 GB2197275A 1

SPECIFICATION

Marine propulsion device with power steering, power shift assist and power throttle assist BACKGROUND OF THE INVENTION

This invention relates to marine propulsion devices, such as outboard motors and stern drive units, including a power steering system.

Attention is directed to the following U.S. patents which disclose power steering systems for marine propulsion devices:

Patentee U.S.Patent No. Issue Date Kobelt 4,399,734 Aug. 23, 1983 Pera: 3,045,434 July 24, 1962 15 Konishi, et al 4,043,123 Aug. 23, 1977 Takahashi, et al 4,193,264 Mar. 18, 1980 Stelzer 2,967,392 Jan. 10, 1961 Mayo 2,906,292 Sept. 29, 1959 Blair 2,910,327 Oct. 27, 1959 20 Hammock 2,939,417 June 7, 1960 Shimanckas 3,631,833 January 4, 1972 Borst 3,774,568 January 27, 1973 Cox et al 4,227,481 October 14, 1980 Borst 4,295,833 October 20, 1981 25 Hall et al 4,373,920 February 15, 1983 Borst 4,419,084 December 6, 1983 Ferguson 4,449,945 May 22, 1984 Hall 4,568,292 February 4, 1986 30 Attention is also directed to pending United States Hall Application Serial No. 484,900 filed April 14, 1983.

SUMMARY OF THE INVENTION

The invention provides a marine propulsion device comprising a propulsion unit including a rotatably mounted propeller, and an engine drivingly connected to the propeller, a member which is movable relative to the propulsion unit, and operator actuated pneumatic means for selectively effecting relative movement between the propulsion unit and the member.

In one embodiment, the pneumatic means operates in relation to a reference pressure, and the 40 marine propulsion device further comprises a soui,ce of pressure different from the normal pressure, the pressure source being connected to the pneumatic means.

In one embodiment, the pressure source provides pressure which is greater than the reference pressure, and the marine propulsion device further comprisesan accumulator connected to the pneumatic means, and a check valve for permitting gas flow from the pressure source to the accumulator and for preventing gas flow from the accumulator to the pressure source.

In one embodiment, the pressure source provides pressure which is less than the reference pressure, and the marine propulsion device further comprises an accumulator connected to the pneumatic means, and a check valve for permitting gas flow from the accumulator to the pressure source and for preventing gas flow from the pressure source to the accumulator.

In one embodiment, the engine further includes a crankcase, and the pressure source includes the crankcase.

In one embodiment, the engine further includes a combustion chamber, and the pressure source includes the combustion chamber.

In one embodiment, the pneumatic means includes a cylinder, a piston slideably mounted in 55 the cylinder and dividing the cylinder into opposite chambers, one of the cylinder and the piston being connected to the member, and a valve assembly communicating with the opposite cham bers of the cylinder for controlling the flow of gases to the cylinder.

In one embodiment, the other of the cylinders and the piston is fixed against movement in the direction axially of the cylinder, the one of the cylinder-and the piston is movable in the direction 60 axially of the cylinder, and the valve assembly includes a valve housing communicating with the opposite chambers of the cylinder, and a valve member movable relative to the valve housing for controlling the flow of gases to the cylinder, one of the valve housing and the valve member being connected to the one of the cylinder and the piston for common movement therewith.

In one embodiment, the pneumatic means further includes operator actuated means for selec- 65 1 2 GB 2 197 275A 2 tively moving the other of the valve housing and the valve member relative to the one of the valve housing and the valve member.

In one embodiment, the propulsion unit further includes a transmission connecting the engine to the propeller, and movement of the member relative to the propulsion unit controls the 5 transmission.

In one embodiment, the engine includes a throttle, and movement of the member relative to the propulsion unit controls the throttle.

In one embodiment, the member is a mounting bracket adapted to be fixedly mounted on the transom of a boat, and the propulsion unit is mounted on the mounting bracket for pivotal movement relative thereto about a generally vertical steering axis, whereby the pneumatic means 10 effects steering movement of the propulsion unit.

The invention also provides an apparatus comprising an engine including a combustion chamber, a movable member, and pneumatic means for moving the member, the pneumatic means communicating with the combustion chamber.

The invention also provides an apparatus comprising an engine including a crankcase subject 15 to cyclical conditions of relatively high and low pressure, a movable member, and pneumatic means for moving the member, the pneumatic means communicating with the crankcase.

A principal feature of the invention is the provision of a marine propulsion device comprising pneumatic power assist means for moving a throttle lever or shift lever, or for steering the propulsion unit.

Another principal feature of the invention is the use of an engine crankcase or combustion chamber as a pressure source for a pneumatic power assist means. This avoids the need for an additional pressure source, such as a pump driven by the engine. Thus, it reduces the cost of providing a power assist means.

Other features, aspects and advantages of the invention will become apparent to those skilled 25 in the art upon reviewing the following detailed description, the drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS 30 Fig. 1 is a side view of an outboard motor embodying various of the features of the invention. 30 Fig. 2 is an enlarged, partially sectioned and partially schematic view of the power shift system of the outboard motor. Fig. 3 is an enlarged, partially sectioned and partially schematic view of the power throttle system of the outboaid motor. 35 Fig. 4 is an enlarged, partially sectioned and partially schematic view of the power steering system of the outboard motor. Before at least one of the embodiments of the invention is explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out 40 in various ways. Also, it is to be understood that the phraseology and cerminology employed herein is for the purpose of description and should not be regarded as limiting.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Patent Specification No. 2,159,483 and U.S. Patent Applications Nos. 710, 494, which was 45 filed March 11, 1985, and 614,821, which was filed May 29, 1984, are incorporated herein by reference.

Illustrated in the drawings is a marine propulsion device 10 which embodies the invention. As shown in Fig. 1, the marine propulsion device 10 comprises a mounting assembly mounted on the transom 12 of a boat. While various suitable mounting assemblies can be used, in the illustrated construction, the mounting assembly includes a transom bracket 14 fixedly mounted on the transom 12, and a swivel bracket 16 mounted on the transom bracket 14 for pivotal movement relative thereto about a generally horizontal tilt axis 18.

The marine propulsion device 10 also comprises a propulsion unit 20 mounted on the swivel bracket 16 for pivotal movement relative thereto about a generally vertical steering axis 22, and 55 for common movement therewith about the tilt axis 18. The propulsion unit 20 includes a rotatably mounted propeller 24, and an engine 26 drivingly connected to the propeller 24 by a conventional drive train including a transmission 28. In the illustrated construction, the engine 26 is a two-cycle internal combustion engine and includes (see Fig. 3) a throttle 30, a crankcase 32, and a pair of cylinders each including a combustion chamber 34. It should be understood 60 that the invention is also applicable to four-cycle engines.

The marine propulsion device 10 also comprises (see Figs. 1 and 4) a steering arm 36 fixedly connected to the propulsion unit 20 for causing steering movement of the propulsion unit 20 relative to the swivel bracket 16, a shift lever or member 38 (Fig. 2) movably mounted on the propulsion unit 20 and operably connected to the transmission 28 for controlling the transmis- 65 3 1 GB2197275A 3 sion 28, and a throttle control lever or member 40 (Fig. 3) movably mounted on the propulsion unit 20 and operably connected to the throttle 30 for controlling the throttle 30. Such arrangements are known in the art and need not be described in greater detail.

The marine propulsion device 10 further comprises (see Fig. 2) operator actuated pneumatic means 42 for selectively effecting relative moVement between the propulsion unit 20 and the shift member 38. While various suitable pneumatic means 42 can be employed, in the preferred embodiment, the pneumatic means 42 includes a cylinder 44, and a piston 46 slideably mounted in the cylinder 44 and dividing the cylinder 44 into opposite upper and lower chambers 48 and 50, respectively. The pneumatic means 42 also includes a piston rod 52 having one end fixedly connected to the piston 46 and an opposite end fixedly connected to the propulsion unit 20. 10 Thus, the piston 46 is fixed against movement in the direction axially of the cylinder 44. The cylinder 44, on the other hand, is movable relative to the piston 46 in the direction axially of the cylinder 44 and is connected to the shift member 38 for common movement. It should be understood that in alternative embodiments the cylinder 44 can be fixed and the piston 46 can be connected to the shift member 38.

The pneumatic means 42 also includes a valve assembly 53 communicating with the opposite chambers of the cylinder 44 for controlling the flow of gases to the cylinder 44. While various suitable valve assemblies can be used, in the illustrated construction, the valve assembly 53 includes a valve housing 54 communicating with the opposite chambers of the cylinder 44, and a valve member 56 movable relative to the valve housing 54 for controlling the flow of gases to 20 the cylinder 44. In the preferred embodiment, the valve housing 54 is connected to the cylinder 44 for common movement therewith. It should be understood that in other alternative embodi ments the valve member 56 can be connected to the cylinder 44 for movement therewith.

As shown in Fig 2, the valve assembly 53 is a conventional spool valve assembly. The valve housing 54 has therein a generally cylindrical bore or cavity 58 in which the valve member or 25 spool 56 is mounted for axial movement between a first or upper position, a second or lower position, and a third or center position (shown in Fig. 2). Fluid or gas may enter or exit the cavity 58 through any of three ports 60, 62, and 64 spaced axially along the valve housing 54.

The port 62 is exposed to a reference pressure, preferably atmospheric pressure. In the illus- trated construction, the port 62 is vented to the atomosphere by a check valve 78 which permits the flow of gases from the port 62 to the atmosphere and which prevents the flow of gases from the atmosphere to the port 62. The valve housing 54 also includes ports 66 and 68 which are located generally opposite the upper port 60 and which communicate with the lower cylinder chamber 50 via a passage 70, and ports 72 and 74 which are located generally opposite the lower port 64 and which communicate with the upper cylinder chamber 48 via a 35 passage 76.

The valve member or spool 56 includes a pair of axially spaced, enlarged, cylindrical portions or lands 80 and 82 which slideably and sealingly engage the interior wall of the cavity 58 during axial movement of the spool 56. When the spool 56 is in the center position, as shown in Fig.

2, the upper land 80 blocks the upper ports 60 and 66, and the lower land 82 blocks the lower 40 ports 64 and 74. At the same time, the ports 68 and 72 both communicate with the port 62 through the cavity 58 and respectively communicate with the cylinder chambers 50 and 48 via the passages 70 and 76.

The valve member or spool 56 also includes shoulder means 84 for engaging the opposite ends of the valve housing 54 and mechanically connecting the valve member 56 with the valve 45 housing 54 in the event the pneumatic means 42 fails.

The marine propulsion device 10 also comprises a source of pressure different from the reference pressure (atmospheric pressure). Preferably, the pressure source is at a pressure higher than atmospheric pressure. While various suitable pressure sources can be employed, in the -50 illustrated construction, the pressure source includes one of the combustion chambers 34 of the 50 engine 26. In an alternative embodiment, as indicated by the dotted lines in Fig. 2, the pressure source can include the crankcase 32 rather than a combustion chamber 34.

The marine propulsion device 10 also comprises an accumulator 86 communicating between the combustion chamber 34 and the valve housing 54. More particularly, the accumulator 86 communicates with the ports 60 and 64 via conduits 94 and 96, respectively, and communi- 55 cates with the combustion chamber 34 via a conduit 88. Preferably, in order to maximize the pressure to which the conduit 88 is exposed, the conduit 88 communicates with the combustion chamber 34 at or near the head of the cylinder. The conduit 88 has therein a check valve 90 which permits gas flow from the combustion chamber 34 to the accumulator 86 and prevents gas flow from the accumulator 86 to the combustion chamber 34. A valve 92 is provided for 60 draining residue from the accumulator 86.

As is known in the art, the combustion chamber 34 is subject to cyclical conditions of relatively high and low pressure. The check valve 90 permits gas flow from the combustion chamber 34 to the accumulator 86 during conditions of high pressure and prevents gas flow from the accumulator 86 to the combustion chamber 34 during conditions of low pressure.

4 GB2197275A 4 Therefore, the accumulator 86 becomes filled with gas at high pressure.

When the valve member 56 is in the center position, as shown in Fig. 2, the upper land 80 blocks the port 60 and the lower land 82 blocks the port 64. Therefore, the accumulator 86 communicates only with the combustion chamber 34 and fills with gas at a pressure equal to the pressure in the combustion chamber 34. Once the pressure in the accumulator 86 reaches 5 the pressure in the combustion chamber 34, there is no pressure loss from the combustion chamber 34 through the conduit 88. Thus, except when the pressure in the accumulator 86 drops due to operation of the pneumatic means 42, the communication of the accumulator 86 with the combustion chamber 34 has no effect upon the operation of the engine 26.

As is obvious from viewing Fig. 2, movement of the valve member 56 to the upper position 10 relative to the valve housing 54 causes communication of the accumulator 86 with the upper cylinder chamber 48 via the port 64, the port 74, and the passage 76 and causes communi cation of the lower cylinder chamber 50 with the atmosphere via the passage 70, the port 68 and the port 62. At the same time, the lower land 82 blocks the port 72 and the upper land 80 blocks the ports 60 and 66. Accordingly, high pressure in the upper cylinder chamber 48 causes 15 the cylinder 44 to move upwardly relative to the piston 46, and this causes the shift member 38 to move upwardly relative to the propulsion unit 20. Upward movement of the cylinder 44 also causes the valve housing 54 to move upwardly relative to the valve member 56, and this returns the valve member 56 to its center position relative to the valve housing 54.

Conversely, movement of the valve member 56 to the lower position relative to the valve housing 54 causes communication of the accumulator 86 with the lower cylinder chamber 50 via the port 60, the port 66 and the passage 70 and causes communication of the upper cylinder chamber 48 with the atmosphere via the passage 76, the port 72 and the port 62. Also, the upper land 80 blocks the port 68 and the lower land 82 blocks the ports 64 and 74. The high pressure in the lower cylinder chamber 50 causes the cylinder 44 to move downwardly relative 25 to the piston 46, and this causes the shift member 38 to move downwardly. Downward movement of the cylinder 44 also causes downward movement of the valve housing 54 relative to the valve member 56, and this returns the valve member 56 to its center position relative to the valve housing 54.

The pneumatic means 42 further includes operator actuated means for selectively moving the 30 valve member 56 relative to the valve housing 54. While various suitable moving means can be employed, in the preferred embodiment, the moving means includes a remotely located shift actuator 98 connected to the valve member 56 by a conventional push-pull cable 100.

As shown in Fig. 3, the marine propulsion device 10 further comprises operator actuated pneumatic means 102 for selectively effecting relative movement between the propulsion unit 20 35 and the throttle member 40. While various suitable pneumatic means 102 can be employed, in the preferred embodiment, the pneumatic means 102 is similar to the pneumatic means 42 and includes (see Fig. 3) a cylinder 104, and a piston 106 slicleably mounted in the cylinder 104 and dividing the cylinder 104 into opposite upper and lower chambers 108 and 110. The pneumatic means 102 also includes a piston rod 112 having one end fixedly connected to the piston 106 40 and an opposite end connected to the throttle member 40. The cylinder 104, on the other hand, is fixedly connected to the propulsion unit 20 and is thus fixed against movement in the direction axially of the cylinder 104.

The pneumatic means 102 also includes a valve assembly 103 which is similar to the valve assembly 53 of the pneumatic means 42. The valve assembly 103 includes a valve housing 114 45 communicating with the opposite chambers of the cylinder 104, and a valve member 116 movable relative to the valve housing 114 for controlling the flow of gases to the cylinder 104.

The valve housing 114 is movable relative to the cylinder 104 and is connected to the throttle member 40 and piston rod 112 for movement therewith.

The valve housing 114 has therein a generally cylindrical bore or cavity 118 in which the valve 50 member 116 is mounted for axial movement between a first or upper position, a second or lower position, and a third or center position (shown in Fig. 3). Fluid or gas may enter or exit the cavity 118 through any of three ports 120, 122, and 124 spaced axially along the valve housing 114. The port 122 is vented to the atmosphere by a check valve 125 which permits the flow of gases from the atmosphere to the port 122 and which prevents the flow of gases 55 from the port 122 to the atmosphere.

The valve housing 114 also includes ports 126 and 128 which are located generally opposite the upper port 120 and which communicate with the lower cylinder chamber 110 via a flexible conduit or passage 130, and ports 132 and 134 which are located generally opposite the lower port 124 and which communicate with the upper cylinder chamber 108 via a flexible conduit or 60 passage 136.

The valve member 116 includes a pair of axially spaced, enlarged, cylindrical portions or lands and 142 which slideably and sealingly engage the interior wall of the cavity 118 during axial movement of the spool 116. When the spool 116 is in the center position, as shown in Fig. 3, the upper land 140 blocks the upper ports 120 and 126, and the lower land 142 blocks the GB2197275A 5 ;i 1 lower ports 124 and 134. At the same time, the ports 128 and 132 both communicate with the port 122 through the cavity 118 and respectively communicate with the cylinder chambers and 108 via the passages 130 and 136.

The marine propulsion device 10 also comprises a source of pressure which is lower than the reference pressure, i.e., atmospheric pressure. In the illustrated construction, the pressure source 5 includes the crankcase 32 of the engine 26.

The marine propulsion device 10 also comp6ses a check valve 146 and an accumulator 148 communicating between the crankcase 32 and the ports 120 and 124. The check valve 146 permits gas flow from the accumulator 148 to the crankcase 32 and prevents gas flow from the crankcase 32 to the accumulator 148. As is known in the art, the crankcase 32 is subject to 10 cyclical conditions of relatively high and low pressure. The check valve 146 permits gas flow from the accumulator 148 to the crankcase 32 during conditions of low pressure and prevents gas flow from the crankcase 32 to the accumulator 148 during conditions of high pressure.

Therefore, the accumulator 148 becomes a vacuum chamber.

The pneumatic means 102 further includes operator actuated means for selectively moving the 15 valve member 116 relative to the valve housing 114. While various suitable moving means can be used, in the illustrated construction, the moving means includes a remotely located throttle actuator 150 connected to the valve member by a conventional push-pull cable 152.

Operation of the pneumatic means 102 is similar to operation of the pneumatic means 42.

Movement of the valve member 116 upwardly relative to the valve housing 114 causes com- 20 munication of the accumulator 148 with the upper cylinder chamber 108 and causes communi cation of the lower cylinder chamber 110 with the atmosphere. Accordingly, low pressure in the upper cylinder chamber 108 causes the piston 106 to move upwardly relative to the cylinder 104, and this causes the throttle member 40 to upwardly relative to the propulsion unit 20.

Upward movement of the piston 106 also causes the valve housing 114 to move upwardly relative to the valve member 116, and this returns the valve member 116 to its original position relative to the valve housing 114.

Conversely, downward movement of the valve member 116 relative to the valve housing 114 causes communication of the accumulator 148 with the lower cylinder chamber 110 and causes communication of the upper cylinder chamber 108 with the atmosphere. The low pressure in the 30 lower cylinder chamber 110 causes the piston 106 to move downwardly relative to the cylinder 104, and this causes the throttle member 40 to move downwardly. Downward movement of the piston 106 also causes downward movement of the valve housing 114 relative to the valve member 116, and this returns the valve member 116 to its original position relative to the valve housing 114.

The marine propulsion device 10 also comprises (see Fig. 4) operator actuated pneumatic means 154 for selectively effecting relative movement between the swivel bracket 16 and the steering arm 36. While various suitable pneumatic means can be employed, in the preferred embodiment, the pneumatic means 154 is substantially identical to the pneumatic means 42.

While the pneumatic means 154 can be connected to any suitable pressure source, for ease of 40 illustration, the pneumatic means 154 is shown in Fig. 4 communicating with the accumulator 86.

As shown in Fig. 4, the pneumatic means 154 includes a piston 156 fixedly attached to the swivel bracket 16, a cylinder 158 connected to the steering arm 36, a valve housing 160 fixedly connected to the cylinder 158, and a valve member 162 movable relative to the valve housing 45 160. Movement of the valve member 162 in one direction causes movement of the steering arm 36 in that direction, and movement of the valve member 162 in the other direction causes movement of the steering arm 36 in that other direction.

The pneumatic means 154 further includes operator actuated means for selectively moving the valve member 162 relative to the valve housing 160. While various suitable moving means can 50 be used, in the illustrated construction, the moving means includes a remotely located steering mechanism 164 connected to the valve member 162 by a push-pull cable 166.

Various features of the invention are set forth in the following claims.

Claims

1. A marine propulsion device comprising a propulsion unit including a rotatably mounted propeller, and an engine drivingly connected to said propeller, a member which is movable relative to said propulsion unit, and operator actuated pneumatic means for selectively effecting relative movement between said propulsion unit and said member.

2. A marine -propulsion device as set forth in, Claim 1 wherein said pneumatic means operates 60 in relation to a reference pressure, and wherein said marine propulsion device further comprises a source of pressure different from said normal pressure, said pressure source being connected to said pneumatic means.

3. A marine propulsion device as set forth in Claim 2 wherein said pressure source provides 65 pressure which is greater than said reference pressure, and wherein said marine propulsion 6 GB 2 197 275A device further comprises an accumulator connected to said pneumatic means, and a check valve for permitting gas flow from said pressure source to said accumulator and for preventing gas flow from said accumulator to said pressure source.

4. A marine propulsion device as set forth in Claim 2 wherein said pressure source provides pressure which is less than said reference pressure, and wherein said marine propulsion device further comprises an accumulator connected to said pneumatic means, and a check valve for permitting gas flow from said accumulator to said pressure source and for preventing gas flow from said pressure source to said accumulator.

5. A marine propulsion device as set forth in Claim 2 wherein said engine further includes a crankcase, and wherein said pressure source includes said crankcase.

6. A marine propulsion device as set forth in Claim 2 wherein said engine further includes a combustion chamber, and wherein said pressure source includes said combustion chamber.

7. A marine propulsion device as set forth in Claim 1 wherein said pneumatic means includes a cylinder, a piston slideably mounted in said cylinder and dividing said cylinder into opposite chambers, one of said cylinder and said piston being connected to said member, and a valve assembly communicating with said opposite chambers of said cylinder for controlling the flow of gases to said cylinder.

8. A marine propulsion device as set forth in Claim 7 wherein the other of said cylinder and said piston is fixed against movement in the direction axially of said cylinder, wherein said one of said cylinder and said piston is movable in the direction axially of said cylinder, and wherein 20 said valve assembly includes a valve housing communicating with said opposite chambers of said cylinder, and a valve member movable relative to said valve housing for controlling the flow of gases to said cylinder, one of said valve housing and said valve member being connected to said one of said cylinder and said piston for common movement therewith.

9. A marine propulsion device as set forth in Claim 8 wherein said pneumatic means further 25 includes operator actuated means for selectively moving the other of said valve housing and said valve member relative to said one of said valve housing and said valve member.

10. A marine propulsion device as set forth in Claim 1 wherein said propulsion unit further includes a transmission connecting said engine to said propeller, and wherein movement of said member relative to said propulsion unit controls said transmission.

11. A marine propulsion device as set forth in Claim 1 wherein said engine includes a throttle, and wherein movement of said member relative to said propulsion unit controls said throttle.

12. A marine propulsion device as set forth in Claim 1 wherein said member is a mounting bracket adapted to be fixedly mounted on the transom of a boat, and wherein said propulsion unit is mounted on said mounting bracket for pivotal movement relative thereto about a generally 35 vertical steering axis, whereby said pneumatic means effects steering movement of said propul sion unit.

13. An apparatus comprising an engine including a combustion chamber, a movable member, and pneumatic means for moving said member, said pneumatic means communicating with said combustion chamber.

14. An apparatus according to Claim 13 wherein said engine also includes a movable control mechanism, and wherein said member is said control mechanism.

15. An apparatus according to Claim 13 wherein said engine includes a throttle, and wherein movement of said member controls said throttle.

16. An apparatus as set forth in Claim 13 wherein said pneumatic means includes a cylinder, 45 a piston slideably mounted in said cylinder and dividing said cylinder into opposite chambers, and a valve assembly communicating with said combustion chamber and with said opposite chambers of said cylinder for controlling the flow of gases to said cylinder.

17. An apparatus as set forth in Claim 16 wherein said valve assembly includes a valve housing communicating with said combustion chamber and with said opposite chambers of said 50 cylinder, and a valve member movable relative to said valve housing for controlling the flow of gases to said cylinder.

18. An apparatus as set forth in Claim 13 and further comprising an accumulator communicat ing with said pneumatic means, and a check valve for permitting gas flow from said combustion chamber to said accumulator and for preventing gas flow from said accumulator to said combus tion chamber.

19. An apparatus comprising an engine including a crankcase subject to cyclical conditions of relatively high member, said pneumatic means communicating with said crankcase.

20. An apparatus according to Claim 19 wherein said engine also includes a movable control 60 mechanism, and wherein said member is said control mechanism.

21. An apparatus according to Claim 19 wherein said engine includes a throttle, and wherein movement of said member controls said throttle.

22. An apparatus as set forth in Claim 19 wherein said pneumatic means includes a cylinder, a piston slideably mounted in said cylinder and dividing said cylinder into opposite chambers, 65 1 and low pressure, a movable member, and pneumatic means for moving said GB2197275A 7 and a valve assembly communicating with said crankcase and with said opposite chambers of said cylinder for controlling the flow of gases to said cylinder.

23. An apparatus as set forth in Claim 22 wherein said valve assembly includes a valve housing communicating with said crankcase and with said opposite chambers of said cylinder, and a valve member movable relative to said valve housing for controlling the flow of gases to 5 said cylinder.

24. An apparatus as set forth in Claim 19 and further comprising an accumulator communicat ing with said pneumatic means, and a check valve for permitting gas flow from said crankcase to said accumulator and for preventing gas flow from said accumulator to said crankcase.

25. An apparatus as set forth in Claim 19 and further comprising an accumulator communicat- 10 ing with said crankcase, and a check valve for permitting gas flow from said accumulator to said crankcase and for preventing gas flow from said crankcase to said accumulator.

26. A marine propulsion device substantially as hereinbefore described with reference to the accompanying drawings.

27. An apparatus substantially as hereinbefore described with reference to the accompanying 15 drawings.

Published 1988 at The Patent Office, State House, 66/71 High Holborn, London WC 1 R 4TP. Further copies may be obtained from The Patent Office, Sales Branch, St Mary Cray, Orpington, Kent BR5 3RD. Printed by Burgess & Son (Abingdon) Ltd. Con. 1/87.

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