JPH0418131B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an adiabatic engine that improves the thermal efficiency of an internal combustion engine by appropriately cooling and insulating the engine.

[Prior Art] One-third of the fuel energy consumed by a general internal combustion engine, whether diesel or gasoline, is output, cooling loss, and exhaust loss, respectively.

Therefore, various adiabatic engines have been proposed that attempt to increase output by insulating the engine combustion chamber and reducing cooling energy loss by 1/3 (Japanese Patent Application Laid-Open No. 1989-1993).
−131017, Utility Model No. 18511, Utility Model Kai No. 18511, Utility Model Kai No. 1857-
No. 101344, No. 123932, No. 123932, No. 123932, No. 123932, No. 57-
139647 etc.).

[Problems to be Solved by the Invention] However, conventionally proposed adiabatic engines use heat insulating walls for the piston, cylinder head, and cylinder block, and use high-temperature walls to provide heat insulation during all strokes of suction, compression, expansion, and exhaust strokes. As a result, the theoretical thermal efficiency was not sufficiently improved due to reasons such as a decrease in the air-fuel mixture suction efficiency and an increase in the air-fuel mixture compression force. That is, in the expansion and exhaust strokes, the adiabatic effect achieves favorable effects such as improving output and reducing cooling energy loss, but in the suction and compression strokes, a problem arises in that it conversely causes a decrease in thermal efficiency.

In order to solve the conventional problems, the present invention reduces the adiabatic effect in the suction and compression strokes in an internal combustion engine, provides sufficient cooling in the suction and compression strokes, and sufficiently insulates the expansion and exhaust strokes. The purpose is to increase theoretical thermal efficiency.

[Means for Solving the Problems] The adiabatic engine of the present invention that meets this objective has a heat-radiating cylinder liner and a heat-insulating cylinder liner on the inner surface thereof, and moves the heat-insulating cylinder liner up and down in synchronization with the stroke of the engine. In the suction and compression strokes, the heat-insulating cylinder liner is lowered relative to the heat-radiating type cylinder liner to expose the inner peripheral surface of the heat-radiating type cylinder liner, and in the expansion and exhaust strokes, the heat-insulating cylinder liner is raised relative to the heat-radiating type cylinder liner to expose the cylinder bore. The inner surface is made up of the inner circumferential surface of a heat-insulating cylinder liner. Heat-radiating cylinder liners are made of materials with high thermal conductivity and are sufficiently cooled by air or liquid cooling during the suction and compression strokes, while insulating cylinder liners are made of materials with low thermal conductivity, such as heat-resistant alloys or ceramics. However, during the expansion and exhaust strokes, the combustion chamber is sufficiently insulated and kept at a high temperature by a high-temperature wall.

[Function] This allows sufficient cooling and expansion in the suction and compression strokes, and sufficient insulation in the exhaust stroke, thereby improving the theoretical thermal efficiency of the engine. In particular, ceramics have material properties such as excellent heat resistance and a small coefficient of thermal expansion, making them ideal for constructing combustion chambers that can reach high temperatures when insulated.

Note that the present invention applies to all internal combustion engines such as gasoline engines and diesel engines.

[Embodiments] Hereinafter, preferred embodiments of the adiabatic engine of the present invention will be described with reference to the drawings.

FIG. 1 shows a cross section of an adiabatic engine according to a first embodiment of the present invention, which is applied to a diesel engine. In the figure, 1 indicates the entire engine, and the engine 1 mainly consists of a cylinder block 2 which is a main body structure, a cylinder head 3 at the upper part of the engine, cylinder liners 4 and 5 which are side walls of a combustion chamber, and a cylinder which moves due to expansion force. It is composed of a piston 6, etc. that performs this.

The cylinder liners consist of a heat-radiating cylinder liner 4 fixed to the block 2 and constantly cooled by cooling fins 7, and a heat-insulating cylinder liner 5 slidably fitted to the inner peripheral surface of the heat-radiating cylinder liner 4.
There are types. The heat-radiating cylinder liner 4 is made of a material with high thermal conductivity, such as an aluminum alloy, and the heat-insulating cylinder liner 5 is made of a material with low thermal conductivity and excellent heat resistance, such as a heat-resistant alloy,
Composed of ceramics.

The heat-insulating cylinder liner 5 is moved up and down relative to the heat-radiating cylinder liner 4 in synchronization with the stroke of the engine by a crank mechanism 9 provided separately from a crank mechanism 8 that converts the reciprocating motion of the piston 6 into rotational motion. It's getting old. The movement of the crank mechanism 9 is synchronized at a rate of 1 rotation for every 2 rotations of the crank mechanism 8, and when the engine is in the suction stroke or the first half of the compression stroke, the heat insulating cylinder liner 5 is placed at the bottom of the heat dissipating cylinder liner 4. It is positioned at the top during the expansion stroke and the first half of the exhaust stroke.

The cylinder head 3 includes an intake port 10 for sucking air into the engine, and an exhaust port 11 for releasing exhaust gas.
It is comprised of a valve 12 that controls intake and exhaust, a cam 13 that opens and closes the valve, and a fuel injection valve 15 that receives fuel from a fuel pump 14 and injects the fuel. Further, the lower part of the engine 1 is covered with an oil pan 16 that holds lubricating oil.

Next, the operation of the above device will be explained.

Figures 2A to 2A show the motion of the adiabatic engine of the present invention. The cooled and low-temperature heat dissipating cylinder liner 4 (white part) is made of a material with high thermal conductivity (aluminum, etc.), and the combustion chamber is kept at a sufficiently low temperature by being cooled by air and liquid cooling on the outside. On the other hand, the insulating cylinder liner 5 (black part), which is insulated and becomes hot, is made of a ceramic material or heat-resistant alloy that has low thermal conductivity and excellent heat resistance. By keeping the combustion chamber at a high temperature, insulation is maintained.

During the intake stroke, as shown in FIGS. 2A to 2C, the high-temperature heat-insulating cylinder liner 5 is lowered to or near the lowest position, and the low-temperature heat-radiating cylinder liner 4 is exposed to the combustion chamber. With this combustion chamber cooled, the piston 6 (shaded area) is lowered and air is taken in.

In the compression stroke, as shown in FIG. 2 (D) to (F), the high temperature heat insulating cylinder liner 5 is raised from the lowered state, and in the first half it is cooled and the low temperature heat dissipating cylinder liner 4 is exposed to the combustion chamber. ,
With the combustion chamber cooled, the piston 6 is raised,
Compression takes place.

During the expansion stroke, the heat-insulating cylinder liner 5 is raised to the top or near the top, and the low-temperature heat-dissipating cylinder liner 4 is covered with the heat-insulating cylinder liner 5, as shown in FIGS. In this way, expansion force is transmitted to the piston 6 while the combustion chamber is insulated.

During the exhaust stroke, as shown in FIG. Exhaust is performed.

Figure 3 shows the effect of the above equipment on the engine.
This is shown using a PV diagram. In the figure, the characteristics of the engine of the present invention are shown by a solid line A, and the characteristics of the conventional engine are shown by a broken line B. Since the compression stroke is sufficiently cooled in the first half of the compression stroke, and since the temperature difference between the inside and outside of the cylinder is not high, the temperature rise inside the cylinder due to the rise of the heat insulating cylinder liner 5 in the second half of the compression stroke is not large, so the compression force remains the same as before. The deviation of the solid line A from the broken line B is relatively small. However, since the piston stroke does not change, the range in which the stroke volume V changes is the same as in the conventional case. On the other hand, since the expansion stroke is insulated by the adiabatic cylinder liner 5 almost throughout the entire expansion stroke, and the difference in temperature between the inside and outside of the cylinder is high due to the temperature rise due to combustion, and the rise in the temperature inside the cylinder due to the rise of the adiabatic cylinder liner 5 is also large. , the combustion gas is kept at a high temperature, its expansion power increases, and the deviation of the solid line A from the broken line B increases. Therefore, in the expansion stroke, the solid line deviates more diagonally upward than the dotted line compared to the compression stroke. Therefore, from the comparison of the area (work) surrounded by the PV diagram in Fig. 3, that is, the comparison of the area surrounded by the solid line A and the broken line B, it is found that the area C of the adiabatic engine of the present invention (solid line A) is larger. , is larger than the area D of the conventional engine (broken line B), so the thermal efficiency of the engine is greater in the adiabatic engine. Furthermore, since the intake stroke is sufficiently cooled, expansion of the intake air is prevented and intake efficiency is high. Therefore, the pressure P at compression top dead center becomes higher than before.

FIG. 4 shows a cross section of an adiabatic engine according to a second embodiment of the present invention. In this embodiment, a cylinder device is used instead of a crank mechanism to move the heat insulating cylinder liner 5 in a low-speed engine in which the speed of vertical movement of the piston is relatively low. A hydraulic cylinder 17 is used as the cylinder device. Hydraulic cylinder 17 controlled by hydraulic pump 18 and driven by hydraulic oil sent through oil pipe 19
The adiabatic high temperature cylinder liner 5 is moved.
In the method in which the crank mechanism is used in the first embodiment to move the heat insulating cylinder liner 5, the movement is close to a sine wave, but in this method using the hydraulic cylinder 17, the degree of freedom in the movement of the heat insulating cylinder liner 5 can be increased. Therefore, the heat insulating cylinder liner 5
The vertical movement of the engine can be more appropriately controlled by synchronizing it with the stroke of the engine. Other configurations, operations, and effects are similar to those in the first embodiment, so similar members are given the same reference numerals as in the first embodiment, and their explanations will be omitted.

In the description of the embodiments of the adiabatic engine of the present invention, an air-cooled engine is shown, but a water-cooled engine may also be used.

[Effects of the Invention] According to the adiabatic engine of the present invention, the high-temperature insulating cylinder liner is moved up and down in synchronization with the stroke of the engine, compared to the low-temperature heat-dissipating cylinder liner. Intake efficiency can be obtained, and high thermal efficiency and high exhaust efficiency can be obtained in the expansion and exhaust strokes.
The thermal efficiency of the engine can be improved.

In addition to the above-mentioned effects, for gasoline engines, knocking can be minimized by cooling the intake compression stroke.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an adiabatic engine according to a first embodiment of the present invention, FIG. 2 A, B, and C are intake strokes of the adiabatic engine of FIG. 1, and FIG. Fig. 2 G, C, and R are expansion strokes, Fig. 2 N,
Fig. 3 is a PV characteristic diagram of the adiabatic engine of the present invention, and Fig. 4 is a diagram of the operation of the exhaust stroke.
1 is a sectional view of an adiabatic engine according to an example. DESCRIPTION OF SYMBOLS 1... Heat insulation engine, 2... Cylinder block, 3... Cylinder head, 4... Heat dissipation type cylinder liner, 5... Heat insulation cylinder liner, 6... Piston, 9... Crank mechanism.

Claims (1)

[Scope of Claims] 1. A cylinder liner for an internal combustion engine is comprised of a heat-radiating cylinder liner made of a material with high thermal conductivity and a material with low thermal conductivity that is slidably fitted on the inner peripheral surface of the heat-radiating cylinder liner. 1. A heat insulating engine comprising a heat insulating cylinder liner made of a material, the heat insulating cylinder liner being moved up and down in synchronization with the stroke of the engine. 2. The heat-insulating engine according to claim 1, wherein the heat-insulating cylinder liner is made of ceramics. 3. The adiabatic engine according to claim 1, wherein the adiabatic cylinder liner is made of a heat-resistant alloy. 4. The adiabatic engine according to claim 1, wherein the vertical movement of the adiabatic cylinder liner is performed by a crank mechanism. 5. The adiabatic engine according to claim 1, wherein the vertical movement of the adiabatic cylinder liner is performed by a cylinder device.