GB2027795A - Internal combustion engine pistons and connecting rods - Google Patents
Internal combustion engine pistons and connecting rods Download PDFInfo
- Publication number
- GB2027795A GB2027795A GB7910675A GB7910675A GB2027795A GB 2027795 A GB2027795 A GB 2027795A GB 7910675 A GB7910675 A GB 7910675A GB 7910675 A GB7910675 A GB 7910675A GB 2027795 A GB2027795 A GB 2027795A
- Authority
- GB
- United Kingdom
- Prior art keywords
- piston
- internal combustion
- combustion engine
- connecting rods
- crankshaft
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
- F01L1/26—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of two or more valves operated simultaneously by same transmitting-gear; peculiar to machines or engines with more than two lift-valves per cylinder
- F01L1/265—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of two or more valves operated simultaneously by same transmitting-gear; peculiar to machines or engines with more than two lift-valves per cylinder peculiar to machines or engines with three or more intake valves per cylinder
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
- F01L1/12—Transmitting gear between valve drive and valve
- F01L1/18—Rocking arms or levers
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
- F02F1/00—Cylinders; Cylinder heads
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
- F02F1/00—Cylinders; Cylinder heads
- F02F1/18—Other cylinders
- F02F1/183—Oval or square cylinders
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B1/00—Engines characterised by fuel-air mixture compression
- F02B1/02—Engines characterised by fuel-air mixture compression with positive ignition
- F02B1/04—Engines characterised by fuel-air mixture compression with positive ignition with fuel-air mixture admission into cylinder
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B75/00—Other engines
- F02B75/02—Engines characterised by their cycles, e.g. six-stroke
- F02B2075/022—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle
- F02B2075/027—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle four
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B2275/00—Other engines, components or details, not provided for in other groups of this subclass
- F02B2275/18—DOHC [Double overhead camshaft]
Abstract
A piston 13 is generally oblong in a cross-section normal to its direction of reciprocation in a correspondingly shaped cylinder 12 and a plurality of connecting rods 17 extend between the piston and a crankshaft 14, the connecting rods being spaced in a direction parallel to the rotary axis of the crankshaft. <IMAGE>
Description
SPECIFICATION
Internal combustion engine
This invention relates to internal combustion engines and is particularly directed to providing a high speed engine having a high horsepower output. In order to improve the horsepower output for each liter of displacement, it has been proposed to increase the maximum engine speed of revolution. However, there are certain disadvantages in this approach.
First, in the range of high revolution speeds, as the engine speed increases the volumetric efficiency falls off. In order to increase the engine speed while maintaining volumetric efficiency at a certain value, it is necessary for the cylinder to be provided with fresh charges of air in an amount proportional to the engine speed of revolution. However, it is known that the velocity of air no longer increases when it reaches about 0.5 mach, and consequently the volumetric efficiency begins to decrease.
In order to obtain higher values for volumetric efficiency, therefore, it is necessary to enlarge the effective opening area of the intake valves. Factors affecting the effective opening area of the intake valves include peripheral length, number of the intake valves, and lift of the intake valves.
Another difficulty with increasing the speed of engine revolutions is that the valve operating mechanism becomes unreliable. When the engine speed exceeds a certain speed range, difficulties are encountered with valve jump, valve bounce, etc. The critical speed of revolution at which such phenomena occur is generally proportional to the square root of the valve spring force, and is inversely proportional to the square root of the least acceleration of the valve. The maximum speed of revolution is limited to that which is determined by these factors.
Furthermore, the upper limit of the engine speed of revolution is soon reached, because the inertia load of the piston and the other reciprocating parts moving with it, e.g. the connecting rod, is proportional to the square of the speed of revolution. Mechanical losses increase abruptly in the range of high speeds.
In order to overcome these problems encountered with high engine speeds, short strokes have been proposed, but there exists a critical range for shorter strokes in order to maintain an effective compression ratio and a combustion chamber configuration on an established displacement. Another proposal for improving power performance has been to improve combustion efficiency, achieved by increasing the compression ratio. However, an excessively high compression ratio produces pre-ignition or knocking. Known characteristics peculiar to fuel, combustion chamber configuration, and ignition timing permit only small increases in performance, and further substantial improvement in performance is not to be expected. Accordingly, proposals for shorter strokes and raised compression ratios have not resulted in significant improvements in performance.
A companion case filed of even date herewith describes and claims an internal combustion engine having at least one piston which is oblong in transverse cross-section and is mounted to reciprocate in sliding contact with a corresponding shaped cylinder. This arrangement permits an improvement in volumetric efficiency which in turn improves the power performance of conventional four cycle gasoline-powered internal combustion engines. The present invention is concerned with the use of plural connecting rods between the oblong piston and the engine crankshaft in order to stabilize the oblong piston against unwanted tilting movement. If only a single connecting rod were used between the piston and the crankshaft, there would be a tendency for the piston to develop a seesaw-like oscillating movement, with a resulting undesirable increase in mechanical losses.
In reciprocating piston engines in general, the piston receives a changing force in the direction of thrust on its side wall during its reciprocating motion. When the piston is oblong, e.g. in the shape of an elongated circle in cross-section, and a single connecting rod extends to the center of the piston, a large bending moment is developed tending to incline the piston, and a result an unwanted sliding resistant develops between the piston and the oblong cylinder wall.
Thus according to the present invention there is provided an internal combustion engine having at least one piston which is oblong in transverse cross-section and is mounted to reciprocate in sliding contact with a correspondingly shaped cylinder, a crankshaft, and a plurality of connecting rods extending between the piston and the crankshaft, the connecting rods being spaced in a direction parallel to the rotary axis of the crankshaft.
An embodiment of the invention will now be described by way of example and with reference to the accompanying drawings, in which Figure 1 is a sectional side elevation partly broken away, showing the relevant parts of an engine according to this invention; and
Figure 2 is a sectional plan view taken substantially on the line 2-2 in Fig. 1.
Referring to the drawings, the engine generally designated 10 has a body 11 provided with four parallel upright cylinders 12. A piston 1 3 reciprocates in each of the cylinders 1 2 but the cooperating sliding surfaces of each piston and cylinder are not circular cylindrical. Instead, each piston and cylinder is elongated in a direction parallel to the rotary axis of the crankshaft 14. The crankshaft 14 is built up of several parts joined together for operation as a unitary assembly.
As best shown in Fig. 2, each cylinder 1 2 is oblong, by which we mean that it has a greater dimension in one direction than in another direction at right angles thereto. The cylinder 1 2 preferably has curved ends 1 5 which each constitute a part of a circle, in cross-section, these curved ends 1 5 being joined by side surfaces 1 6 which are preferably in the form of parallel planes. However, the side surfaces 1 6 may be arched to increase the lateral dimension of the cylinder, or the cross-section of the cylinder may be in the form of an ellipse. It is intended that the term "oblong" cover any of these shapes, among others.Each cylinder 1 2 is symmetrical about a plane passing through the longest of the cylinder cross-sections.
Two duplicate connecting rods 17 connect each piston 1 3 to a crank throw 1 8 formed on the crankshaft 14. Each connecting rod 17 has a portion encircling a pin 1 9 mounted in the piston 1 3 and extending in a direction parallel to the axis of the crankshaft 14. The piston 13 has end supports 21 and 22 and a central support 23 which are aligned and which carry the piston pin 19. The upper ends 25 of the connecting rods 1 7 each encircle a portion of the pin 1 9 between the centre support 23 and one of the end supports 21, 22. Piston rings 27 seal the sliding contact between each piston 1 3 and its respective cylinder 12. The crankshaft 14 is supported in the body 11 by means of a series of axially spaced bearings 28.
While only two connecting rods 1 7 are shown in the drawings, a greater number of connecting rods may be employed, if desired, between each oblong piston and the crankshaft 14.
Claims (5)
1. An internal combustion engine having at least one piston which is oblong in transverse cross-section and is mounted to reciprocate in sliding contact with a correspondingly shaped cylinder, a crankshaft, and a plurality of connecting rods extending between the piston and the crankshaft, the connecting rods being spaced in a direction parallel to the rotary axis of the crankshaft.
2. An internal combustion engine as claimed in claim 1, in which both the piston and cylinder as seen in transverse cross-section have spaced end portions each comprising a part of a circle.
3. An internal combustion engine as claimed in claim 1 or 2, wherein the said connecting rods are two in number and are duplicates of each other.
4. An internal combustion engine as claimed in any of claims 1 to 3, in which the piston has a piston pin mounted in two end supports and a central support, a first said connecting rod having a portion encircling said piston pin on one side of said central support, and a second said connecting rod having a portion encircling said piston pin on the other of said central support.
5. An internal combustion engine substantially as hereinbefore described with reference to the accompanying drawings.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3484278A JPS54129206A (en) | 1978-03-28 | 1978-03-28 | Internal combustion engine |
| JP1978040106U JPS5856452Y2 (en) | 1978-03-30 | 1978-03-30 | Reciprocating engine conrod device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB2027795A true GB2027795A (en) | 1980-02-27 |
Family
ID=26373704
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7910675A Withdrawn GB2027795A (en) | 1978-03-28 | 1979-03-27 | Internal combustion engine pistons and connecting rods |
Country Status (3)
| Country | Link |
|---|---|
| DE (1) | DE2911888A1 (en) |
| FR (1) | FR2421311A1 (en) |
| GB (1) | GB2027795A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2130670A (en) * | 1982-11-19 | 1984-06-06 | Tuenkers Maschinenbau Gmbh | Pressure-medium-operable toggle lever clamping device |
| US4671219A (en) * | 1982-09-11 | 1987-06-09 | Honda Giken Kogyo Kabushiki Kaisha | Two-stroke internal combustion engine |
| EP1451658A1 (en) * | 2001-12-06 | 2004-09-01 | Mac Valves Inc. | Pneumatic pressure regulator assembly |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3124791C2 (en) * | 1981-06-24 | 1983-03-24 | MTU Motoren- und Turbinen-Union München GmbH, 8000 München | Piston, in particular of an internal combustion engine, with piston pin, piston pin intermediate support and power transmission member |
| US4548125A (en) * | 1982-07-01 | 1985-10-22 | Mtu Motorn-Und Turbinen Union Gmbh | Piston arrangement, particularly for an internal combustion engine |
| US5133314A (en) * | 1991-12-23 | 1992-07-28 | Langstroth Steven W | Linkage arms for minimizing piston wobble |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR521591A (en) * | 1918-01-21 | 1921-07-16 | C Motors 1920 Ltd Ab | Improvements to cylinders and pistons for internal combustion engines |
| US2257417A (en) * | 1940-04-08 | 1941-09-30 | Frank H Kelley | Power cylinder for internal combustion engines |
-
1979
- 1979-03-26 FR FR7907498A patent/FR2421311A1/en active Pending
- 1979-03-26 DE DE19792911888 patent/DE2911888A1/en active Pending
- 1979-03-27 GB GB7910675A patent/GB2027795A/en not_active Withdrawn
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4671219A (en) * | 1982-09-11 | 1987-06-09 | Honda Giken Kogyo Kabushiki Kaisha | Two-stroke internal combustion engine |
| GB2130670A (en) * | 1982-11-19 | 1984-06-06 | Tuenkers Maschinenbau Gmbh | Pressure-medium-operable toggle lever clamping device |
| EP1451658A1 (en) * | 2001-12-06 | 2004-09-01 | Mac Valves Inc. | Pneumatic pressure regulator assembly |
| EP1451658A4 (en) * | 2001-12-06 | 2005-03-23 | Mac Valves Inc | Pneumatic pressure regulator assembly |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2421311A1 (en) | 1979-10-26 |
| DE2911888A1 (en) | 1979-10-25 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |