JPS5951669B2 - internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates primarily to reciprocating internal combustion engines for automobiles and other vehicles.

The applicant of the present application has previously developed an engine of this type in which a cylinder sleeve is inserted into an oval cylinder consisting of semicircular parts on both outer sides and a straight or gently curved part in the middle of the semicircular part. We have proposed a type in which a shaped piston is slidably fitted into the cylinder sleeve, but in this case, the cylinder sleeve generally has a substantially uniform wall thickness over its entire circumference; The internal pressure that is applied tends to cause large distortions, especially in the intermediate straight portions.In other words, the distortions become non-uniform over the entire circumference, which can easily cause seizures, gas leaks, etc. Accompany.

The object of the present invention is to provide an engine free of such inconveniences, and in an oval cylinder consisting of both outer semicircular parts and a straight or gently curved straight part in the middle, In an internal combustion engine in which pistons having substantially the same shape are slidably fitted together through a cylinder sleeve, the pistons of the pistons are positioned in the longitudinal direction of an oblong shape, and the cylinder sleeve is inserted into the semicircular shape at the straight portion. The feature is that the wall thickness is increased compared to the other parts.

An example of implementing the present invention will be explained with reference to the attached drawings. In the drawings, 1 indicates a cylinder, and the cylinder 1 has both outer semicircular parts 1a,
A piston 3 having approximately the same shape, that is, an elliptical shape, is slidably inserted into the cylinder sleeve 2 via a cylinder sleeve 2. They are fitted together, and the piston pin 7 is shaped like an ellipse in the longitudinal direction, thus forming a reciprocating engine as a whole. In the drawings, reference numeral 4 indicates an intake and exhaust valve on the upper surface of the cylinder 1, 5 indicates a crankshaft below the cylinder 1, and 6 indicates a connecting rod that connects the shaft 5 to the piston 3. The cylinder 1 is made of a light alloy other than aluminum, and is made of a light alloy other than aluminum, and the cylinder sleeve 2 is fixed thereto by casting or press fitting. I made it.

Although the above is not particularly different from what was previously proposed, according to the present invention, the wall thickness of the cylinder sleeve 2 is increased at the intermediate straight portion compared to the semicircular portions on both outer sides, for example. This is clearly shown in Figure 2.

To explain this in detail, for example, if we consider a case where the internal pressure P acts uniformly inside an oval cylinder a as shown in Figure 3, the bending moment acting at each point will be large in the semicircular shape at the straight part. The distribution is, for example, as shown by line M in FIG. 4. According to the inventor's calculations, if the radius of each semicircular part is r, the distance between the center points inside each half is 21, and 1/r-1.3, then the center point C of the straight part The strain at point A at the center of the half interior is 1.883, assuming that the wall thickness of each part and therefore the moment of inertia of the area are equal.
It turned out to be double. In other words, point C will be distorted nearly twice as much as point A, which may cause seizure or gas leakage. In order to deal with this, the wall thickness of each part, that is, the moment of inertia of area, is adapted to this, and the distortion of each part is equalized.For example, the moment of inertia of area at point A is made equal to the moment of inertia of area at point C. 1.8
It is set as 1/83rd. One example is clearly shown in FIG. 2, and this idea is applied to the cylinder sleeve 2.

That is, the sleeve 2 has a relatively large wall thickness at the straight portion.
That is, the moment of inertia of area was large, and it was made relatively small inside the half. In this way, according to the present invention, the elliptical piston has its piston pin positioned in the longitudinal direction of the ellipse, so the piston is swung in the lateral direction of the ellipse and moves inside the cylinder. The cylinder sleeve can be moved quietly by reducing the vibration of the piston, and the wall thickness of the cylinder sleeve is increased in the middle straight part compared to the inside of each of the outer halves. This has the effect of making the distortion of each beam as uniform as possible in response to changes in the force.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional side view of one example of the engine of the present invention, FIG. 2 is a cross-sectional view taken along line I--11, and FIGS. 3 and 4 are explanatory diagrams thereof. 1...Cylinder, 1a, 1a...half inside, 1b...
- Straight part, 2... cylinder sleeve, 3... piston.

Claims (1)

[Claims] 1. A piston of approximately the same shape is slidably fitted into an elliptical cylinder consisting of both outer semicircular parts and a straight or gently curved straight part in the middle via a cylinder sleeve. An internal combustion engine characterized in that the piston pin of the piston is located in the longitudinal direction of an oval shape, and the cylinder sleeve has a wall thickness greater in the straight part than in the semicircular part.