JP2711563B2 - Variable cycle number engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to a variable cycle number that operates in two cycles when the engine speed is equal to or lower than a predetermined speed, and in four cycles when the engine speed is equal to or higher than the predetermined speed. About the engine.

(Prior Art) Conventional engines are roughly classified into two-stroke engines and four-stroke engines according to differences in the stroke of each rotation of an engine output shaft. Since the two-stroke engine executes the explosion stroke every rotation of the engine output shaft, fluctuations in the rotation speed of the engine output shaft are small and high torque can be generated. On the other hand, the four-stroke engine has a feature that the fuel consumption rate is small since the explosion stroke is executed every two revolutions and the exhaust stroke and the intake stroke are independent.

(Problems to be Solved by the Invention) However, since the two-stroke engine executes the intake stroke and the exhaust stroke simultaneously in parallel, there is a problem that the intake and exhaust are not completely performed, and the fuel consumption rate is large. . On the other hand, the four-stroke engine has a problem that the rotational speed of the engine output shaft fluctuates greatly, so that the torque is insufficient in a low rotational speed region and smooth operation cannot be performed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has been made in consideration of the above-described circumstances. It aims to provide a variable engine.

(Means for Solving the Problems) According to the present invention, an intake port formed in a cylinder cylindrical surface corresponding to a position of a piston upper surface near a bottom dead center, and intake air is pressure-fed from the intake port into the cylinder. A supercharger having an electric motor installed on a compressor and a turbine shaft; and a pair of permanent magnets having a pair of magnetic poles provided at an upper portion of the cylinder and provided at an upper end portion of the exhaust valve. Valve driving means comprising a magnetic pole and a coil arranged side by side at a distance from each other and driving the opening and closing of an exhaust valve by the electromagnetic force, and the exhaust valve is a top dead stroke of discharging exhaust gas in a cylinder by a supercharging pressure. At this point, the exhaust port is closed, and in the closed state, the piston is lowered to adiabatically expand the intake air in the cylinder, and at the bottom dead center, the intake air is injected into the cylinder by the negative pressure action and the supercharging pressure in the cylinder. Fuel control means for variably controlling fuel injection timing into a combustion chamber covered with a heat-resistant heat insulating material to form a heat shielding structure, a rotating electric machine for powering the supercharging means, and an engine. When the rotation speed is lower than the predetermined rotation speed, the boosting pressure increasing means for driving the rotating electric machine with electric power, opening and closing of the exhaust valve and fuel injection are performed when the rotation speed of the engine is equal to or higher than the predetermined rotation speed. Is executed every two rotations of the engine output shaft, and has an exhaust valve and cycle changing means for executing fuel injection every one rotation.

Further, in the above invention, when the engine is at a predetermined rotation speed and a predetermined load or more, electric energy is collected by using a turbocharger attached to an exhaust port and a motor provided at a turbine attached to the junction thereof as a generator. The variable cycle number engine described above can also be provided.

(Operation) The variable cycle number engine of the present invention operates as a two-cycle engine in a region equal to or lower than a predetermined rotation speed, and operates as a four-cycle engine in a region equal to or higher than the predetermined rotation speed. Thus, a high-torque engine having a smooth engine rotation speed is obtained, and a high-efficiency engine having a small fuel consumption rate in a middle to high rotation speed region is obtained.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an engine according to the present invention, FIG. 2 is a sectional view taken along line II in FIG. 1, and FIG. 3 is a sectional view taken along line II-II in FIG.

A cylinder sleeve 11 is provided on the inner peripheral surface of the cylinder 1, and an intake port 13 is provided around the piston head near the bottom dead center of the cylinder sleeve 11.
The intake port 13 is inclined and opened so that the intake air turns clockwise.

A sub-combustion chamber 2 is provided at the center of the upper part of the cylinder 1, and the inner surface of the sub-combustion chamber 2 is covered with a sleeve 21 made of ceramics or the like as a heat-resistant heat insulating material. The sleeve 21 and the cylinder sleeve 11 are connected via a heat insulating gasket 12. An injection nozzle 22 for injecting fuel clockwise into the sub-combustion chamber 2 is provided at a side of the sub-combustion chamber 2, and the injection nozzle 22 is a fuel whose injection timing and injection amount are variable. Connected to pump 23. Also,
The sub-combustion chamber 2 is provided with an exhaust port for discharging exhaust gas through the sub-combustion chamber 2, and the exhaust port is provided with an exhaust valve 24.
It is opened and closed by. The exhaust valve 24 is driven to open and close by a valve driving device 6 disposed on the shaft.

A piston 3 is provided inside the cylinder 1, and a piston head surface of the piston 3 is coated with a heat-resistant heat insulating material, such as ceramics, similarly to the sub-combustion chamber 2. A projection 31 is formed at the center of the piston head, and narrows the opening of the sub-combustion chamber 2 when the piston 3 is near the top dead center.

Exhaust gas discharged from the exhaust port is guided to a turbine of the turbocharger 4 through an exhaust pipe 41. A rotating electric machine 43 is connected to the rotating shaft of the turbocharger 4, and has a structure capable of generating a supercharging pressure by supplying power from the outside. In addition, turbocharger 4
The exhaust gas that has passed through is guided to the recovery turbine 44, converts the energy still contained in the exhaust gas into electric energy, and regenerates it through the control unit 5. The turbocharger 4 applies a supercharging pressure to intake air for rotating the compressor using exhaust gas or electric power from the outside, and supplies the intake air to the intake port 13 through the intake pipe 42.

The valve driving device 6, the fuel pump 23 and the rotating electric machine 43
Is the input / output interface 50 of the control unit 5
Is controlled by a signal from In addition to the above, a rotation sensor 55 for detecting the number of revolutions and the crank angle of the engine, an accelerator sensor 56 for detecting the amount of depression of the accelerator pedal, and a generator for the recovery turbine are connected to the input / output interface 50. The signal from the sensor and the regenerative power are input. In addition to the input / output interface 50, the control unit 5 has a ROM 53 for storing programs and various relational tables, a CPU 51 for executing calculations under the programs in the ROM 53, and an R for temporarily storing calculation results and data.
It comprises an AM 54, a control memory 52 for controlling the signal flow inside the control unit 5, and the like.

 Next, the valve driving device 6 will be described.

 FIG. 4 is a detailed view of the valve driving device 6.

A permanent magnet 61 and a permanent magnet 62 are fitted to the shaft end of the exhaust valve 24 at predetermined intervals. The polarities of the outer peripheral portions of the permanent magnets 61 and 62 are different from each other. For example, if the outer peripheral portion of the permanent magnet 61 is N pole, the outer peripheral portion of the permanent magnet 62 is S pole. The exhaust valve faces the outer peripheral portions of the permanent magnets 61 and 62.
Magnetic poles 63 are arranged side by side at different intervals between the permanent magnets 61 and 62 in the moving direction of the coil 24, and a coil 64 for controlling the polarity of the magnetic pole 63 is wound around each of the magnetic poles 63.

The energization of each of the coils 64 is controlled by the control unit 5 and sequentially changes the polarity of the magnetic pole 63 on the side facing the permanent magnet, and by the resultant of the electromagnetic force acting between the permanent magnets 61 and 62 and the magnetic pole 63. The exhaust valve 24 is driven in the opening / closing direction.

Next, a case where the engine according to the present invention is operated as a two-cycle engine will be described.

When the expansion stroke ends and the piston 3 approaches the bottom dead center,
The intake air to which the supercharging pressure is added flows from the intake port 13 into the cylinder, and forms a swirling flow in the circumferential direction. Next, the exhaust gas is pushed up with the rise of the piston 3 and is scavenged from the exhaust port. However, since the opening area of the sub-combustion chamber 2 is large, the exhaust resistance is small and scavenging can be performed quickly. Then, the exhaust valve 24 closes the exhaust port during the rise of the piston, and shifts to the compression stroke to compress the intake air. With the rise of the piston 3, the intake air in the cylinder 1 moves to the sub-combustion chamber 2, but since the diameter of the sub-combustion chamber 2 is smaller than the cylinder diameter, the swirling flow in the cylinder 1 is accelerated and the sub-combustion chamber is accelerated. 2 flows into. In the latter half of the compression stroke, the inflow decreases, but the protrusion 31 formed on the piston head narrows the opening area of the sub-combustion chamber 2 and accelerates the flow velocity of the swirling flow flowing into the sub-combustion chamber 2. Therefore, at the end of the compression, a restricted swirling flow is generated inside the sub-combustion chamber 2.

Next, when fuel is injected from the injection nozzle 22 in the swirling flow direction, the fuel burns and shifts to an expansion stroke. All of the injected fuel is burned in the sub-combustion chamber 2 to become combustion gas, and the piston 3
Descend. Then, the opening area of the sub-combustion chamber 2 narrowed by the protrusion 31 is enlarged by the lowering of the piston 3, and the combustion gas is quickly diffused into the cylinder. Then, the exhaust valve 24 is driven during the lowering of the piston 3 to open the exhaust port and exhaust the exhaust gas. Then, the above cycle is repeated following the intake stroke.

Next, a case where the engine according to the present invention is operated as a four-cycle engine will be described.

FIG. 5 is a p-v diagram of the four-stroke engine, and FIG. 6 is a diagram showing a part of the stroke of the four-stroke engine.
The states at points a to e in FIG. 5 are shown in a to e in FIG.

In the expansion stroke after combustion, when the volume increases from the top dead center V1 in the compressed state to V2 immediately before the bottom dead center, the exhaust port is opened to start discharging the exhaust gas. Then, the pressure rapidly decreases while passing through the point a and expanding to the bottom dead center V3. Since the intake port 13 is already opened at the bottom dead center shown at point b, the intake air loaded with the supercharging pressure becomes a swirling flow and flows into the cylinder 1. Exhaust is further pushed upward by the inflowing intake air, and exhaustion from the exhaust port is promoted. Even if the piston 3 moves upward from the bottom dead center and the intake port is closed to stop the inflow of intake air, the exhaust gas still remains in the cylinder 1 so that the exhaust port is opened as shown at point c. Is continued. Then, the exhaust port is kept open to the top dead center and exhaust gas in the cylinder is completely exhausted.
Next, at the top dead center V1, the exhaust port is closed as shown at point d. When the piston 3 descends while the exhaust port is kept closed, the intake air sealed in the cylinder is adiabatically expanded. During the adiabatic expansion, the temperature of the enclosed intake air drops, so that heat energy is quickly taken from the combustion chamber wall surface. Then, when passing through the position where the intake port immediately before V3 opens, that is, point e, the intake air rapidly flows into the cylinder by the action of the supercharging pressure and the negative pressure in the cylinder 1. The intake port 13 is inclined with respect to the center direction as shown in FIG. 3, so that the intake air takes a high-speed swirling flow in the cylinder 1.

Subsequently, the swirl flow in the cylinder 1 moves into the sub-combustion chamber 2 with the rise of the piston 3, but the swirl flow in the cylinder 1 is smaller because the diameter of the sub-combustion chamber 2 is smaller than the cylinder diameter. The flow is accelerated and flows into the sub-combustion chamber 2. In the latter half of the compression stroke, the inflow decreases, but the projection 31 formed on the piston head narrows the opening area of the sub-combustion chamber 2,
Since the flow velocity of the swirling flow flowing into the sub-combustion chamber 2 is accelerated, a higher-speed swirling flow is generated inside the sub-combustion chamber 2 at the end of compression. At the end of the compression stroke, the inner wall surface has already been cooled,
When the fuel is injected from the injection nozzle 22 in the swirling flow direction, the fuel burns in a good state and shifts to the expansion stroke. The injected fuel is entirely burned in the sub-combustion chamber 2 to become combustion gas, and the piston 3 is lowered. However, the opening area of the sub-combustion chamber 2 narrowed by the projection 31 is enlarged by the drop of the piston 3, and the combustion gas is reduced. Quickly diffuses into the cylinder.

Next, the operation of the engine according to the present invention will be described.

FIG. 7 is a diagram showing the relationship between the rotation speed and the torque in the engine of the present invention. In the figure, the horizontal axis indicates the engine speed N, and the vertical axis indicates the torque T.

In the region where the engine speed N detected by the rotation sensor 55 is equal to or higher than the predetermined speed N2, the exhaust valve 24 is opened and closed and the fuel is injected from the injection nozzle 22 every two revolutions of the engine output shaft to operate as the above-described four-cycle engine. .

In the region where the engine speed is equal to or lower than the predetermined speed N2, the engine operates as the two-cycle engine described above. And
In a region where the engine speed is equal to or lower than N1 where the engine speed is low, the exhaust energy is insufficient. Therefore, electric power is supplied to the rotating electric machine 43 to forcibly increase the supercharging pressure of the intake air to increase the torque. When the engine load increases in the range of N1 or more, the electric power is supplied to the rotating electric machine 43 to increase the supercharging pressure, and the amount of fuel supplied from the fuel pump 23 to the injection nozzle 22 is increased. To increase the output.

By the above-described operation, the torque of the engine according to the present invention has a characteristic of increasing as the rotational speed decreases, and the engine becomes an optimal engine as a driving power source of the vehicle. It is possible to make it.

Although the present invention has been described above, various different embodiments can be easily configured without departing from the spirit of the present invention. Therefore, the present invention is not limited to any particular embodiment except for the limitations described in the claims. It is not something to be done.

(Effects of the Invention) As described above, according to the present invention, the engine is operated as a two-cycle engine in a region of a predetermined rotation speed or less,
Since the engine is operated as a four-cycle engine in the region where the rotation speed is equal to or higher than the predetermined rotation speed, a high-torque engine having a smooth engine rotation speed is provided in the low and middle rotation speed regions, and a high-efficiency engine having a small fuel consumption rate in the middle and high rotation speed region. Thus, it is possible to provide a variable cycle number engine that can reduce or abolish the number of gears of the transmission, which is conventionally indispensable when used as a driving power source for a vehicle.

In addition to this, the present invention closes the exhaust port at the top dead center of the process of discharging the exhaust gas in the cylinder by the supercharging pressure by the exhaust valve driven by the valve driving device, and lowers the piston in the closed state. Adiabatic expansion of the intake air in the cylinder, and at the bottom dead center, the intake air suddenly flows into the cylinder by the negative pressure action and the supercharging pressure in the cylinder, so that a high-speed swirling flow is obtained and the suction effect is improved. effective. Further, by providing the permanent magnet in the valve driving device at the upper end of the exhaust valve, there is an effect of further increasing the valve driving force.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a sectional view taken along line II in FIG. 1, FIG. 3 is a sectional view taken along line II-II in FIG. 1, and FIG. FIG. 5 is a pv diagram of a four-stroke engine, FIG.
The figure shows a part of a four-stroke engine, and FIG.
FIG. 4 is a diagram illustrating a relationship between a rotation speed and a torque. 1 ... cylinder, 2 ... auxiliary combustion chamber, 3 ... piston, 4
... turbocharger, 5 ... control unit,
6 ... Valve drive device.

Claims (2)

(57) [Claims] An intake port formed in a cylindrical surface of a cylinder corresponding to a position of an upper surface of a piston near a bottom dead center, a compressor for pumping intake air from the intake port into a cylinder, and an electric motor mounted on a turbine shaft. A supercharging means having a magnetic pole provided at the upper part of the cylinder, provided with a pair of permanent magnets having different magnetic poles at the upper end of the exhaust valve, and arranged in parallel with an outer peripheral portion facing the permanent magnet so as to be spaced apart in the axial direction. Composed of coils,
Valve driving means for opening and closing an exhaust valve by the electromagnetic force, wherein the exhaust valve closes the exhaust port at a top dead center in a process of discharging exhaust gas in a cylinder by a supercharging pressure,
In the closed state, the piston is lowered to adiabatically expand the intake air in the cylinder, and at the bottom dead center, the intake air suddenly flows into the cylinder by the negative pressure action in the cylinder and the supercharging pressure. Fuel control means for variably controlling the timing of fuel injection into the covered and heat-insulated combustion chamber; a rotating electric machine for powering the supercharging means; and an engine speed lower than the predetermined speed. At this time, the boost pressure increasing means for driving the rotating electric machine by electric power, and opening and closing of the exhaust valve and fuel injection are executed every two rotations of the engine output shaft when the engine rotation speed is equal to or higher than a predetermined rotation speed. A variable cycle number engine comprising a valve and cycle changing means for executing fuel injection for each rotation. 2. The method according to claim 1, wherein when the engine has a predetermined number of revolutions and a predetermined load or more, electric energy is recovered by using a turbocharger attached to the exhaust port and a motor provided on a turbine attached to the junction thereof as a generator. The variable cycle number engine according to claim 1, wherein: