JPS5913309Y2 - multi-cylinder internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multi-cylinder internal combustion engine in which the piston diameter-to-stroke ratios are varied between the cylinders so that the cylinders are operated at ratios appropriate to the operating conditions of the engine.

In Japanese Patent Application No. 53-000852, the present applicant has proposed a multi-cylinder engine in which the piston diameter-stroke ratio is varied between cylinders.

In other words, in this multi-cylinder engine, the combinations of piston diameter and stroke are different between the cylinders, and in some cylinders the piston diameter is larger than the stroke (overskeying), and in other cylinders the piston diameter is smaller than the stroke. During high-speed driving, the highly efficient over-scaled cylinders are activated, and during low-speed driving, the more suitable reverse-scaled cylinders are activated, thereby achieving the maximum fuel efficiency while obtaining sufficient output. .

By the way, in such an internal combustion engine, not all cylinders are necessarily in operation, which is expected to be disadvantageous in terms of engine rotational balance and vibration.

Therefore, the purpose of the present invention is to address this, and for this purpose the piston diameter and stroke are selected so that the displacement is substantially the same for all cylinders.

As a result of having a common displacement, the combustion pressure in each cylinder is made constant, which is advantageous in terms of vibration and rotational balance.

Next, embodiments of the present invention will be specifically described with reference to the drawings.

In FIG. 1, which schematically shows the relationship between each piston and the crank arm when the present invention is applied to a four-cylinder engine, 1-1.1-2.1-3 and 1-4 are #1, respectively.
These are the pistons for #2, #3, and #4 cylinders.

In this example, pistons 1-1 and 1 of cylinders #1 and #2
The diameter R of cylinder -4 is large, while the diameter r of pistons 1-2 and 1-3 of cylinders #2 and #3 is small.

3 is a crankshaft, and its arm portion is 3-1. 3-2.
3-3 and 3-4.

The height 1 of the arms 3-1 and 3-4 of the cylinders #1 and #4 is small, and the height L of the arms 3-2 and 3-3 of the cylinders #2 and #3 is large. ing.

The connecting rods 7 all have a common length and are connected to the pistons 1-1. 1-2. 1-3 and 1-4 are respectively crank arm parts 3-1. 3-2. 3-3 and 3-4
is connected to.

Thus, the piston diameter-stroke ratio is large in cylinder #L #4 and small in cylinders #2 and #3, creating an engine in which this ratio changes between the cylinders.

The connecting rod 7 is connected to the piston at a low position in the #1 and #4 cylinders, and a high position in the #2 and #3 cylinders because the top dead center of the piston is connected to the straight line m-
This is to make the cylinders match like m.

Also, in Figure 1, the left half of the piston shows the top dead center, and the half corresponds to the bottom dead center, but in reality, the piston and crank arm are not positioned like this, but as shown in Figure 2. It is better to place it in terms of rotational balance.

That is, A is the cylinder with a large diameter-stroke ratio, that is, #1
and #4 crank arm 31.3-4 is placed in a diametrically opposite position, and the cylinders with a small diameter-stroke ratio, that is, the crank arms 32.3-3 of #2 and #3 are placed in a diametrically opposed position so as to form a cross shape. The -auspicious days are arranged in a straight line.

Further, in the illustrated embodiment, #1 and #4 are made to have diameter-stroke submergence, and #2 and #3 are made to be diameter-stroke metamorphosis, but the combination is not limited to this, and other combinations may also be used.

In FIG. 1, the cylinder head recess corresponding to the piston crown is designated by 9-1. 9-2. 9-3. 9-4, the recess 9-1.9-4 corresponding to the large diameter piston 1-1.1-4 has a large diameter and a shallow depth; The corresponding recesses 9-2, 9-3 are preferably of smaller diameter and somewhat deeper.

The table below shows the actual values for piston diameter and stroke.

In the present invention, the piston diameter and stroke are selected as shown in the table above, so that the displacement corresponding to = (piston diameter) 2 x stroke can be substantially the same for all cylinders.

Therefore, the combustion pressure will be balanced among the cylinders, which will be advantageous as a countermeasure against vibration.

The operation of each cylinder is similar to that disclosed in Japanese Patent Application No. 53-000852.

That is, when engine output is required for starting, accelerating, overtaking, climbing, etc., all cylinders are activated.

Also, when driving at high speed on a flat road or downhill road that does not require power, only the cylinders with a large piston diameter-to-stroke ratio (#1 and #4 in the example) are operated, and the other cylinders do not send fuel, while the other cylinders do not send fuel. During low-speed operation, only the cylinders with small piston diameter-to-stroke ratios (#2 and #3 in the embodiment) are operated, and fuel is not sent to other cylinders.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram of a multi-cylinder engine according to the present invention, and FIG. 2 is a diagram showing the arrangement of crank arms in the engine according to the present invention. 1-1.1-2.1-3, 1-4...Piston, 3-1.3-2.3-3.3-4...Crank arm.

Claims (1)

[Scope of utility model registration request] In a multi-cylinder internal combustion engine in which the piston diameter-stroke ratio is different between the cylinders and the cylinders are operated at a ratio suitable for the operating conditions of the engine, the air volume per cylinder of the gold cylinders is substantially the same. Multi-cylinder internal combustion engine where the piston diameter and stroke are selected for each cylinder.