JP2730198B2 - 4-cycle insulated engine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a four-stroke adiabatic engine in which a lower surface portion of a cylinder head and an upper portion of a cylinder liner have a heat insulating structure.

[Conventional technology]

2. Description of the Related Art Conventionally, an insulated engine in which a ceramic liner head having a cylinder liner is fitted inside a cylinder head is disclosed in, for example, Japanese Patent Application Laid-Open No. 59-122765.

Generally, the operation of a gasoline engine or a diesel engine is performed by repeating four operations of an intake process, a compression process, a combustion process, and an exhaust process, and in each of these processes, power is generated and torque is applied to a crankshaft. Only the combustion process is performed, and the other three processes are performed by inertia. There are two types of operating principles of each of these processes, a four-cycle engine and a two-cycle engine. In particular, a four-stroke engine is an engine that requires four strokes of the piston, that is, two rotations of the crankshaft, to complete the one cycle by performing the above four operations for each step of the piston. As described above, the four-cycle engine is provided with one stroke, that is, sufficient time for the exhaust process and the intake process, has a high volumetric efficiency, a high average effective pressure, is particularly efficient at a high speed, and has two crankshaft rotations. On the other hand, one combustion step is performed, and the thermal load on each part can be reduced.

Conventionally, as a valve mechanism of an internal combustion engine, a valve mechanism in which an intake / exhaust valve is electrically configured and electrically driven is disclosed in, for example, Japanese Patent Application Laid-Open No. 58-183805.

[Problems to be solved by the invention]

By the way, with regard to the above-described insulated engine, a combustion chamber formed of a cylinder formed in a cylinder head and a cylinder block is formed integrally with a cylinder head lower surface portion and a cylinder liner upper portion. A heat insulating material is arranged from a material or the like to form a heat insulating structure, and volumetric efficiency is reduced due to high heat in the cylinder, resulting in a reduction in output. The reason is that the intake valve and the exhaust valve are arranged on the cylinder head and are arranged close to each other.Moreover, in an insulated engine, the cylinder head and the upper part of the cylinder are insulated, so the upper part of the combustion chamber and the wall surface become hot, The temperature of the exhaust gas and the upper part of the combustion chamber is considerably higher. Therefore, the intake port and the intake air are easily thermally affected by the exhaust port, the upper wall of the combustion chamber, and the exhaust gas, and the fresh air sucked into the cylinder receives heat from the cylinder or the wall surface and expands by heating. Expands due to thermal effects and the intake air volume becomes extremely high, for example,
It can be reduced to more than 20%, which lowers the inhalation efficiency. In addition, the suction efficiency of the adiabatic engine decreases as the speed decreases, as compared with the cooling engine. That is, the lower the engine speed, the larger the time area in the suction process, the longer the time during which the intake air is affected by heat, and the lower the suction efficiency.

However, in a two-cycle engine, the intake port is provided below the cylinder liner, and the intake air is not affected by the heat of the exhaust gas, the exhaust port, and the upper wall of the combustion chamber. In the replacement, when the arrangement valve is opened and the gas is exhausted through the exhaust port, a pressure wave or a pulse wave is generated in the cylinder, and the exhaust gas is pushed out. As a result, fresh air flows into the negative pressure zone generated downstream of the exhaust gas from the lower part of the cylinder, but since the lower part of the cylinder is not so hot compared to the cylinder head, the fresh air is Insensitive to wall temperature. This has the merit that the scavenged air amount or the intake air amount does not decrease particularly if the adiabatic engine performs two-cycle operation and sucks fresh air from the lower part of the cylinder.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-described problems. In an adiabatic engine in which the upper part of a combustion chamber including a cylinder head and a cylinder is configured to have an adiabatic structure, the operation cycle is controlled to improve the suction efficiency, and the four-cycle The cylinder head is hot, but the lower part of the cylinder farther from the cylinder head is not hot, so the intake port is located at the lower part of the cylinder, separated from the exhaust port. The air intake port is provided at the bottom of the cylinder liner to shorten the suction period to reduce the time area. The pressure difference between the cylinder internal pressure and the intake air pressure should be increased accordingly. Also, the intake area is increased to improve the intake flow condition, a predetermined intake air volume is secured, and the valve is made of a lightweight ceramic material to open and close the valve with electromagnetic force to open and close the valve. By controlling the valve, the valve can be freely controlled independently of the rotation of the crank, and an intake control valve is arranged in an intake port formed below the cylinder liner. A four-stroke insulated engine characterized by controlling the intake control valve to close in the process and opening the intake control valve near the bottom dead center where the stone after the exhaust process reaches the intake port to improve intake efficiency. To provide.

[Means for solving the problem]

The present invention is configured as follows to achieve the above object. That is, the present invention provides a cylinder head lower surface portion and a cylinder liner upper portion configured in a heat insulating structure, an exhaust valve disposed on the cylinder head lower surface portion, a number of intake ports formed in a circumferential direction of a cylinder liner lower portion before a bottom dead center, Guide scrolls around the cylinder liner leading to the intake port,
And an intake control valve provided in an intake passage leading to the guide scroll and opened after the exhaust stroke and closed during the explosion stroke and the exhaust stroke.

The four-cycle adiabatic engine includes an electromagnetic valve driving device that opens and closes the intake valve with electromagnetic force.

[Action]

The four-cycle adiabatic engine according to the present invention is configured as described above, and operates as follows.

This four-cycle insulated engine has an exhaust valve arranged on the lower surface of a cylinder head having an upper part of a combustion chamber formed in an insulated structure, a number of intake ports formed in a lower circumferential direction of a cylinder liner before a bottom dead center, and a cylinder communicating with the intake ports. A guide scroll is provided on the outer periphery of the liner, and an intake control valve is provided in an intake passage communicating with the guide scroll and opened after the exhaust process and closed during the explosion process and the exhaust process. The backflow of exhaust gas can be prevented, and the intake air is not affected at all by the high-temperature exhaust gas and the heat of the upper wall of the high-temperature combustion chamber, the temperature of the intake air does not rise, and the exhaust valve is located before bottom dead center. , The pressure in the cylinder drops rapidly, and after the end of the exhaust stroke, the exhaust valve closes and the piston moves down to close the exhaust valve. Sunda in becomes negative pressure, the intake control valve is opened at the bottom dead center before the piston. Since the intake port, i.e., the intake port, is arranged on the outer periphery of the cylinder, the area can be increased and the time area in the intake process can be increased even if the valve opening period is short, and since the time is short, heat reception of intake air is suppressed. And the internal pressure is lowered by the lowering process of the piston, the differential pressure between the cylinder internal pressure and the intake air pressure becomes large, and the intake air in a low temperature state without being affected by the heat is quickly sent into the cylinder in the negative pressure state for a short time. Thus, a predetermined amount of intake air is sucked, so that the suction efficiency can be improved.

Further, since the intake passage communicates with the guide scroll below the cylinder liner, the swirling flow of the intake air is increased, and the intake air is easily sucked into the cylinder.

〔Example〕

Hereinafter, an embodiment of a four-cycle adiabatic engine according to the present invention will be described with reference to the drawings.

1 and 2 show an embodiment of a four-cycle adiabatic engine according to the present invention. FIG. 1 is a schematic sectional view showing an embodiment of a four-cycle insulated engine according to the present invention, and FIG. 2 is a sectional view of a lower part of a cylinder liner of the four-cycle insulated engine of FIG. In this four-cycle insulated engine, the exhaust valve 1 is connected to the cylinder head 3
The exhaust process is performed by airflow in a certain direction with respect to the cylinder center line. A valve seat 19 is disposed at the inlet of the exhaust port 20, and the exhaust valve 1 has a valve face. It is arranged so that it can be opened and closed so as to be adjacent to the valve seat 19. A cylinder liner 9 made of a ceramic material or a metal material is fitted into a cylinder formed in the cylinder block 4, and a number of intake ports 12 are formed in a lower part of the cylinder liner 9 in a circumferential direction. The intake port 12 communicates with the guide scroll 11 which is an annular intake passage formed in the cylinder block 4. Further, the guide scroll 11 is connected to a supercharger formed of a turbocharger, a compressor or the like.

The structure in the upper part of the combustion chamber 8 is a headliner 5 of an integral structure composed of a cylinder head lower surface part 6 of a cylinder head 3 and a cylinder liner upper part 7 constituting a cylinder.
Is made of a ceramic material such as silicon nitride (Si ₃ N ₄ ) or silicon carbide (SiC), and is disposed so as to be fitted to the lower surface of the cylinder head 3. A heat insulating gasket 10 made of a heat insulating material is interposed between the heat insulating gasket 10 and the lower surface of the gasket. In addition, headliner 5
At the boundary between the lower end of the cylinder liner upper part 7 and the upper end surface of the lower part of the cylinder liner 9, a heat insulating gasket 15 made of a heat insulating material is provided to prevent the generation of heat flow from the liner upper part 7 to the lower part of the liner 9. Intervening. Although not shown, the piston 13 that reciprocates in the cylinder has a heat insulating structure made of a ceramic material or the like.
In the figure, reference numeral 16 denotes a piston ring.

By arranging the heat insulating gasket 15 at the boundary between the upper part 7 of the cylinder liner and the lower part of the cylinder liner 9,
The temperature distribution of the wall surface constituting the combustion chamber 8 is, for example, assuming that the temperature of the cylinder head lower surface portion 6 constituting the fire deck of the cylinder head 3 is 600 ° C., the temperature of the boundary portion where the heat insulating gasket 15 is disposed is 300 ° C. ° C, the temperature at the lower part of the cylinder liner 9 where the intake port 12 is formed becomes 200 ° C or less. Therefore, the structure can be configured such that heat is insulated in the combustion process of the engine and cooled in the expansion process.

Also, in this four-cycle insulated engine,
A large number of 12 are formed on the lower circumference of the cylinder liner 9 before the bottom dead center of the piston 13, and a guide scroll 11 which is an annular passage communicating with the intake passage 17 is formed on the outer peripheral surface of the cylinder liner 9. Are formed. Multiple inlets 12
Are connected to the guide scroll 11, and the shape of the intake port 12 is formed so as to be inclined with respect to the radial direction and the axial direction of the cylinder liner 9 so that the intake air flows along the flow line. Further, the intake passage 17 is provided with an intake control valve 2 for opening and closing the intake passage 17. It is preferable that the intake control valve 2 is configured to be opened and closed by an electromagnetic force by an electromagnetic valve driving device described later, for example. By making the intake control valve 2 from a lightweight non-magnetic material of ceramic material, the valve can be opened and closed by electromagnetic force to control the opening and closing timing, and the valve can be freely opened independently of the rotation of the crank. Can be controlled. Therefore, when the intake control valve 2 is closed in the explosion process and the exhaust process, and the piston 13 after the exhaust process is located near the bottom dead center just before reaching the intake port 12, the intake control valve 2 is opened. Can be controlled. The exhaust valve 1 may be opened by a valve mechanism such as a cam as in a normal engine.
It goes without saying that the opening and closing operation may be performed by the electromagnetic valve driving device.

In addition, in this four-cycle insulated engine, the intake passage 17 can be connected to a supercharger composed of a turbocharger, a compressor, or the like. The torque can be increased.

Further, in this four-cycle adiabatic engine, the exhaust valve 1 and the intake control valve 2 can be configured to open and close by electromagnetic force. The opening and closing timing of each of the valves 1 and 2 can be suppressed to an optimal state in response to a detection signal from a position sensor that detects a stroke position, that is, a crank angle. That is, each valve 1, 2
The electromagnetic valve driving device is for opening and closing the valve by electromagnetic force, a rotation sensor for detecting the number of revolutions of the engine, a load sensor for detecting the load of the engine, a stroke position of the piston 13, that is, a position for detecting the crank angle. It can be controlled by a controller that receives each detection signal from a sensor and an intake air flow sensor that detects the amount of intake air, and issues a command in response to each of these detection signals. The engine load sensor detects the engine load, and can be detected by detecting the amount of fuel supplied from the injection nozzle of the fuel injection device to the engine or by detecting the amount of depression of the accelerator pedal. is there.

Further, the fuel injection device for controlling the fuel supplied to the engine has an injection nozzle, and the injection nozzle is connected to the cylinder head 3.
Is provided in the combustion chamber 8 or the intake passage 17 from above, and the fuel injected from the injection nozzle is spray-introduced into the cylinder. This fuel injection device is controlled so as to inject a predetermined amount of fuel according to a command from a controller. In addition, a rotation sensor is provided for the output shaft of the engine, and detects the engine speed. The detected value of the engine speed, that is, the rotation signal is input to the controller.

When the intake control valve 2 reciprocates by the electromagnetic valve driving device, the intake passage 17 of the cylinder block 4 is moved.
The intake passage 17 is opened and closed by coming into contact with or detaching from the valve seat 14 installed in the vehicle.

The four-stroke adiabatic engine according to the present invention is configured as described above, and comprises the components shown in FIGS. 3, 4 (A), 4 (B), 4 (C), and 4 (D). The operation cycle of the four-cycle adiabatic engine will be described with reference to FIG.
FIG. 3 shows a PV diagram for a four-cycle adiabatic engine according to the present invention, and FIGS. 4 (A), 4 (B), 4 (C) and 4 (D) It is explanatory drawing which shows the state of each operation cycle.

In FIG. 3, in order to explain the operation cycle of the engine, a change in the gas state in the cylinder in one cycle is shown, and the volume V is plotted on the horizontal axis and the pressure P is plotted on the vertical axis. Here, since the pressure receiving area of the piston is constant, the horizontal axis can indicate the position of the piston process, the left end is the top dead center TDC, and the right end is the bottom dead center B.
It corresponds to the DC position. The piston stroke is a function of the crank angle, and the pressure P on the horizontal axis can be plotted as the crank angle.

In the intake process of the engine cycle, for example, the exhaust valve 1 is closed by an electromagnetic valve driving device, and the fourth valve is closed.
As shown by an arrow E in FIG.
It descends from DC, that is, point a in FIG. The negative pressure in the cylinder, that is, in the combustion chamber 8 is gradually increased.
Does negative work (indicated by oblique line A) and piston 13 is at bottom dead center
If the intake port 12 is set to be opened in the cylinder when the point b near the BDC reaches, for example, about 50 ° at the crank angle before the end of the bottom dead center BDC, the intake control valve 2 is set to the electromagnetic valve. Already released by the drive,
Moreover, the intake air is boosted by a supercharger such as a turbocharger and stands by at the intake port, that is, the guide scroll 11 and the intake passage 17 without being affected by the exhaust gas and the heat of the upper part of the combustion chamber. Through the intake passage 17, the guide scroll 11, and the intake port 12, the intake air flows into the cylinder in a negative pressure state at a stretch, and the pressure in the cylinder is, as shown by the point c, even if the engine speed is low, the time area is reduced. The piston 13 ascends to secure a predetermined intake air amount in a small state, and the piston 13 reaches the bottom dead center BDC.

Next, as shown by an arrow F in FIG. 4 (B), the process proceeds to the compression step, and the piston 13 moves to the bottom dead center BDC, that is, the point c in FIG.
The piston 13 first passes through the intake port 12 and closes, so that the suction of the intake air into the cylinder is shut off, the inside of the cylinder is compressed, and the intake control valve 2 is closed. Subsequently, the air-fuel mixture is compressed by the rise of the piston 13 until reaching the point d, and the temperature and the pressure rise. At the top dead center TDC at the end of the compression process, the mixture is ignited or ignited and moves to the combustion process. Air mixture cylinder pressure in the combustion reaches the highest pressure P _MAX, combustion period along from the point d to a line of the point e terminates. In the explosion process, as shown by the arrow G in FIG. 4 (C), the piston 13 descends and is pressed down by the high-pressure gas generated by combustion along the line from the point e to the point f to perform work. The work process proceeds, and the exhaust gas burns down and lowers the piston, but performs a positive work (indicated by oblique line W + oblique line B), and the end of the work process reaches bottom dead center BDC (corresponding to point f). Until the exhaust valve 1 is opened. When the exhaust valve 1 is opened, the exhaust gas is ejected to the exhaust pipe at a sonic speed to cause a blow-down phenomenon, and the pressure in the cylinder rapidly decreases to a point g, and the work process ends.

At the subsequent start of the exhaust stroke, the cylinder internal pressure shows a high value in the conventional engine cycle as shown by a point h in FIG. 3, but in the operation cycle according to the present invention, the cylinder internal pressure becomes almost large. Returning to the state at the point g close to the atmospheric pressure, the exhaust process is performed along the line from the point g to the point a as shown by the arrow H in FIG. That is, the gas is exhausted out of the combustion chamber 8 through the exhaust port 20.

Therefore, the four-stroke adiabatic engine according to the present invention
After the evacuation process, when the piston 13 descends, it performs a negative work (shown by a hatched line A in the figure), but performs a positive work (a hatched line B in the figure).
) Is added to the positive work (shown by diagonal line W in the figure), so that the negative work (shown by diagonal line A in the figure) and the positive work (shown by diagonal line B in the figure) are offset, An operation capable of securing substantially positive work (indicated by a hatched line W in the figure) becomes possible. In addition, since the intake air is sucked into the cylinder under the negative pressure state at a stretch in a short time without being affected by heat, the intake efficiency is improved particularly in the case of an insulated engine as described above. be able to.

〔The invention's effect〕

The four-stroke insulated engine according to the present invention is configured as described above, and has the following effects. That is,
This four-cycle insulated engine has a cylinder head lower surface part and an upper part of a cylinder liner configured in a heat insulating structure, an exhaust valve arranged on the cylinder head lower part, a large number of intake ports formed in a circumferential direction of a cylinder liner lower part before a bottom dead center, A guide scroll is provided on the outer periphery of a cylinder liner communicating with the intake port, and an intake control valve is provided in an intake passage communicating with the guide scroll, and is opened after an exhaust process and closed during an explosion process and an exhaust process. The structure is not affected by high temperature parts such as the cylinder head wall surface provided with the port, the exhaust gas, the exhaust port, etc., so that the temperature of the intake air does not rise and the thermal expansion of the intake air does not occur. In addition, the intake control valve can prevent exhaust gas from flowing back into the intake passage during the explosion process and the exhaust process. The exhaust valve is opened near the bottom dead center and the pressure in the cylinder drops rapidly.After the exhaust process is completed, the exhaust valve closes and the pressure in the cylinder becomes negative due to the lowering of the piston. The intake control valve opens just before the point. Since the intake port, i.e., the intake port, is arranged on the outer periphery of the cylinder, the area can be increased and the time area in the intake process can be increased even if the valve opening period is short, and since the time is short, heat reception of intake air is suppressed. And the internal pressure is reduced by the process of lowering the piston, the differential pressure between the cylinder internal pressure and the intake air pressure increases, and the intake area can be increased to improve the intake air intake state. A predetermined amount of intake air is sucked into the cylinder in a short time in a short period of time, so that the suction efficiency can be improved.

Also, the present invention focuses on the fact that the valve can be freely controlled independently of the rotation of the crank by controlling the opening / closing timing by operating the valve by electromagnetic force by manufacturing the valve from a lightweight material such as a ceramic material. The control is performed such that the intake control valve arranged at the intake port formed below the cylinder liner closes the intake control valve in the explosion process and the exhaust process and opens near the bottom dead center where the piston reaches the intake port after the exhaust process. be able to.

Therefore, in an adiabatic engine, it is possible to provide an engine that utilizes the characteristics of a four-cycle type in which an intake port capable of improving the intake efficiency is provided below the cylinder liner.

Further, since the intake passage communicates with the guide scroll below the cylinder liner, the swirling flow of the intake air is increased, and the intake air is easily sucked into the cylinder.

[Brief description of the drawings]

FIG. 1 shows an embodiment of a four-cycle adiabatic engine according to the present invention, and is a sectional view taken along line II of FIG.
FIG. 3 is a sectional view showing the lower part of the cylinder liner of the four-cycle insulated engine shown in FIG. 1, FIG. 3 is an explanatory view showing a PV diagram of the four-cycle insulated engine, and FIGS. (B), FIG. 4 (C) and FIG. 4 (D) are explanatory diagrams showing states of each operation cycle of the four-cycle adiabatic engine according to the present invention. 1 ... exhaust valve, 2 ... intake control valve, 3
…… Cylinder head, 4 …… Cylinder block, 6…
Cylinder head lower part, 7 ... Cylinder liner upper part, 8
... combustion chamber, 9 ... cylinder liner, 10, 15 ... heat insulating gasket, 11 ... guide scroll, 12 ... intake port, 13
... piston, 17 ... intake passage.

Claims (2)

(57) [Claims] 1. A lower surface of a cylinder head and an upper portion of a cylinder liner having an insulating structure, an exhaust valve disposed on the lower surface of the cylinder head, a number of intake ports formed in a circumferential direction of a lower portion of the cylinder liner before a bottom dead center, and the intake air. A four-stroke insulated engine comprising: a guide scroll provided on an outer periphery of a cylinder liner leading to an opening; and an intake control valve provided in an intake passage leading to the guide scroll and opened after an exhaust process and closed during an explosion process and an exhaust process. 2. The four-stroke adiabatic engine according to claim 1, further comprising an electromagnetic valve driving device for opening and closing the intake control valve by electromagnetic force.