JPH02286833A - Variable cycle engine - Google Patents

Abstract

PURPOSE:To improve the torque and the efficiency by providing a fuel control means which variably controls a fuel injection timing to a combustion chamber and a cycle change means which changes the opening and the closing of an exhaust valve and the fuel injection. CONSTITUTION:Intake parts 13 are bored at the inner circumference of a cylinder 1 which is corresponding to the upper face position of a piston in the vicinity of a bottom dead point. At a turbo charger 4, intake air is pressure-supplied into the cylinder 1 from the intake ports 13. An exhaust valve 24 is driven openly and closely by a valve drive device 6. The valve drive device 6, a fuel pump 23 and a revolving armature 43 are controlled by a signal from input and output interfaces 50 of a control unit 5. The opening and closing of the exhaust valve 24 and the fuel injection are performed at every one rotation of an engine output shaft in a case where the number of the engine revolutions is more than a specified level. Consequently, the torque and the effecting are improved.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention provides a variable number of cycles that operates in 2 cycles when the engine rotational speed is below a predetermined rotational speed and 4 cycles when the engine rotational speed is above a predetermined rotational speed. Regarding the engine.

(Prior Art) Conventional engines can be broadly classified into two-stroke engines and four-stroke engines, depending on the difference in stroke per rotation of the engine output shaft. Since a two-stroke engine executes an explosive stroke for each rotation of the engine output shaft, fluctuations in the rotational speed of the engine output shaft are small and high torque can be generated.

On the other hand, a four-stroke engine performs an explosion stroke every two revolutions, and the exhaust stroke and intake stroke are independent, so the fuel consumption rate is low.

(Problem to be Solved by the Invention) However, since the above-mentioned two-stroke engine executes the intake stroke and the exhaust stroke simultaneously and in parallel, there is a problem that the intake and exhaust are not completed completely, resulting in a high fuel consumption rate. . On the other hand, a four-cycle engine has a problem in that the rotational speed of the engine output shaft fluctuates greatly, resulting in insufficient torque in a low rotational speed region, making smooth operation impossible.

The present invention has been made in view of the above points, and has a number of cycles in which the engine can be operated as a 2-cycle engine in a region below a predetermined rotation speed, and as a 4-cycle engine in a region above the predetermined rotation speed. It attempts to provide a variable engine.

(Means for Solving the Problems) According to the present invention, an intake port is provided in the cylinder cylindrical surface corresponding to the position of the upper surface of the piston near the bottom dead center, and intake air is forced into the cylinder from the intake port. A supercharging means, an exhaust port provided at the top of the cylinder and whose opening and closing are controlled by an exhaust valve, a valve drive means which opens and closes the exhaust valve by electromagnetic force, and which variably controls the timing and amount of fuel injection into the combustion chamber. The fuel control means, the opening/closing of the exhaust valve and the fuel injection are executed every one rotation of the engine output shaft when the engine rotation speed is above a predetermined rotation speed, and every two rotations when the engine rotation speed is below a predetermined rotation speed. It is possible to provide a cycle number variable engine characterized by having a cycle changing means for changing the number of cycles.

(Function) The variable cycle number engine of the present invention operates as a 2-cycle engine in the region below a predetermined rotation speed, and as a 4-stroke engine in the region above the predetermined rotation speed, so in the low and medium rotation speed region. This results in a high-torque engine with smooth engine rotational speed, and a high-efficiency engine with low fuel consumption in the medium and high rotational speed range.

(Example) Hereinafter, an example 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 cross-sectional view taken along line II in FIG. 1, and FIG. 3 is a cross-sectional view taken along line II-II in FIG.

A cylinder sleeve 11 is disposed on the inner peripheral surface of the cylinder 1, and an intake port 13 is disposed around the piston head near the bottom dead center of the cylinder sleeve 11. The intake port 13 opens at an angle so that the intake air is rotated clockwise.

A sub-combustion chamber 2 is provided in 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 a heat-resistant heat insulating material such as ceramics. 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 interior of the auxiliary combustion chamber 2 is disposed on the side of the auxiliary combustion chamber 2. It is connected to the pump 23. Further, 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 opened and closed by an exhaust valve 24. The exhaust valve 24 is driven to open and close by a valve driving device 6 disposed on the shaft.

A piston 3 is disposed inside the cylinder 1,
The piston head surface of the piston 3 is covered with a heat-resistant heat insulating material such as ceramics, like the sub-combustion chamber 2. Further, a projection 31 is formed in 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 the turbine of the turbocharger 4 through an exhaust pipe line 41. A rotating electric machine 43 is connected to the rotating shaft of the turbocharger 4, and has a structure capable of generating supercharging pressure by supplying power from the outside. Also, turbocharger 4
The exhaust gas that has passed through is guided to the recovery turbine 44, which converts the energy that the exhaust gas still has into electrical energy and regenerates it via the control unit 5. Note that the turbocharger 4 rotates a compressor using exhaust gas or external electric power to apply supercharging pressure to intake air, and supplies the intake air to the intake port 13 via an intake pipe 42 .

The above-mentioned valve drive device 6, fuel pump 23 and rotating electric machine 4
3 is controlled by signals from an input/output interface 50 of the control unit 5. In addition to the above, the input/output interface 5o is connected to a rotation sensor 55 that detects the engine speed and crank angle, an accelerator sensor 56 that detects the amount of depression of the accelerator pedal, and a generator for the recovery turbine. Signals from the sensor and regenerated power are input. The control unit 5
In addition to the input/output interface 5o, the ROM 53 stores programs and various relational tables;
A CPU 51 that executes calculations according to the program, a RAM 54 that temporarily stores calculation results and data, and a control memory 5 that controls signal flow inside the control unit 5.
2, etc.

Next, the valve drive device 6 will be explained.

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

A permanent magnet 61 and a permanent magnet 62 are fitted into the shaft end of the exhaust valve 24 at a predetermined interval. The permanent magnets 61 and 6
The polarities of the outer circumferential portions of the permanent magnets 61 and 2 are different from each other; for example, if the outer circumferential portion of the permanent magnet 61 is the north pole, the outer circumferential portion of the permanent magnet 62 is the south pole. Magnetic poles 63 are arranged in parallel at different intervals from the permanent magnets 61 and 62 in the six movement directions of the exhaust valve 24, facing the outer peripheral portions of the permanent magnets 61 and 62,
A coil 64 for controlling the polarity of the magnetic pole 63 is wound around each of the magnetic poles 63 .

The power supply to each of the coils 64 is controlled by the control unit 5, and the polarity of the side of the magnetic pole 63 facing the permanent magnet is sequentially changed, and the resultant force of the electromagnetic force acting between the permanent magnets 61 and 62 and the magnetic pole 63 is used. The exhaust valve 24 is driven in the opening and closing directions.

Next, a case will be described in which the engine according to the present invention is operated as a two-stroke engine.

When the expansion stroke is completed and the piston 3 is near the bottom dead center, intake air to which supercharging pressure has been added flows from the intake port 13 into the cylinder, forming a swirling flow in the circumferential direction.

Next, as the piston 3 rises, the exhaust gas is pushed up and scavenged from the exhaust port, but since the opening area of the auxiliary combustion chamber 2 is large, the exhaust resistance is small, and the gas can be scavenged quickly. Then, while the piston is rising, the exhaust port is closed by the exhaust valve 24, and a compression stroke is started to compress the intake air. As the piston 3 rises, the intake air in the cylinder i flows into the auxiliary combustion chamber 2.
However, since the diameter of sub-combustion chamber 2 is smaller than the cylinder diameter, the swirling flow inside cylinder i is accelerated and moves to sub-combustion chamber 2.
Flow inward. In the latter half of the compression stroke, the inflow amount decreases, but the protrusion 31 formed on the piston head
The opening area of the combustion chamber 2 is narrowed, and the velocity of the swirling flow flowing into the sub-combustion chamber 2 is accelerated. Therefore, at the end of compression, a high-speed swirling flow is generated inside the sub-combustion chamber 2.

Next, when fuel is injected from the injection nozzle 22 in the direction of the swirling flow, the fuel burns and shifts to the expansion stroke.

All of the injected fuel burns in the auxiliary combustion chamber 2 and becomes combustion gas, causing the piston 3 to descend. Then, the opening area of the auxiliary combustion chamber 2, which had been narrowed by the protrusion 31, is expanded by the descent of the piston 3, and the combustion gas quickly diffuses into the cylinder. Then, while the piston 3 is descending, the exhaust valve 24 is driven to open the exhaust port and discharge the exhaust gas. Then, following the intake stroke, the above cycle is repeated.

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

Figure 5 is a p-vjJ1 diagram of a 4-cycle engine, and Figure 6
The figure is a diagram showing a part of the stroke of a four-stroke engine. Note that the state of points a-e in Fig. 5 is expressed as a in Fig. 6.
Shown in %e.

In the expansion stroke after combustion, when the volume increases from top dead center V1 in a compressed state to v2 just before bottom dead center, the exhaust port is opened and exhaust gas starts to be discharged.

Then, the pressure decreases rapidly while passing through point a and expanding to bottom dead center v3. Then, since the intake port 13 is already opened at the bottom dead center shown at point b, the intake air loaded with supercharging pressure becomes a swirling flow and flows into the cylinder 1. The inflowing intake air pushes the exhaust air further upwards and promotes its discharge from the exhaust port. Even if the piston 3 moves upward from the bottom dead center and the intake port is closed and the intake air stops flowing, exhaust gas still remains in the cylinder 1.
The exhaust port continues to be opened as shown at point 0. and,
The exhaust port is kept open until the top dead center to completely exhaust the exhaust gas inside the cylinder. Next, at top dead center ■1, close the exhaust port as shown at point d. When the piston 3 descends while keeping the exhaust port closed, the intake air sealed in the cylinder is expanded adiabatically. During this adiabatic expansion, the temperature of the sealed intake air drops, so thermal energy is rapidly taken away from the combustion chamber wall surface.When the intake air passes through the position where the intake port opens just before v3, that is, point e, the intake air reaches the supercharging pressure. Due to the action of the negative pressure inside the cylinder 1, it rapidly flows into the cylinder.

Since the intake port 13 is inclined with respect to the center direction as shown in FIG. 3, the intake air becomes a high-speed swirling flow within the cylinder 1.

Subsequently, as the piston 3 rises, the swirling flow in the cylinder i moves into 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 i moves into the sub-combustion chamber 2. The flow is accelerated and flows into the sub-combustion chamber 2. In the second half of the compression stroke, the inflow amount decreases, but the protrusion 31 formed on the piston head narrows the opening area of the auxiliary combustion chamber 2, and the auxiliary combustion chamber 2
Since the flow velocity of the swirling flow flowing into the auxiliary 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, so
When the fuel is injected from the injection nozzle 22 in the direction of the swirling flow, the fuel burns in a good condition and shifts to the expansion stroke. All of the injected fuel burns in the sub-combustion chamber 2 and becomes combustion gas, which causes the piston 3 to descend. However, the opening area of the sub-combustion chamber 2, which had been narrowed by the protrusion 31, is expanded by the descent of the piston 3, and the combustion gas quickly diffuses into the cylinder.

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

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

When the engine speed N detected by the rotation sensor 55 is equal to or higher than the predetermined speed N2, the exhaust pulp 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 four-cycle engine. .

In a region where the engine rotational speed is equal to or lower than the predetermined rotational speed N2, the engine operates as a two-cycle engine as described above. and,
In the region where the engine speed is low (lower than N1),
Since the exhaust energy is insufficient, torque is increased by supplying electric power to the rotating electric machine 43 and forcibly increasing the supercharging pressure of the intake air. Note that when the engine load increases in the region of N1 or more, power is supplied to the rotating electrical machine 43 to increase the boost pressure, and the amount of fuel supplied from the fuel pump 23 to the injection nozzle 22 is increased. increase the output of

Through the above operation, the torque of the engine according to the present invention increases as the rotation speed decreases, making it the optimal engine as a driving power source for vehicles, and reducing or eliminating the number of gears of the transmission, which was previously considered indispensable. It becomes possible to force them.

Although the present invention has been described above, since various different embodiments can be easily constructed without departing from the spirit of the invention, the present invention is not limited to specific embodiments other than the limitations set forth in the claims. It is not something that will be done.

(Effects of the Invention) As explained above, according to the present invention, the engine operates as a 2-cycle engine in the region below a predetermined rotation speed, and operates as a 4-cycle engine in the region above the predetermined rotation speed. In the medium-speed range, the engine becomes a high-torque engine with smooth rotation speed, and in the medium-high speed range, it becomes a high-efficiency engine with low fuel consumption, which has traditionally been considered indispensable when used as a driving power source for vehicles. It is possible to provide a cycle number variable engine that can reduce or eliminate the number of gears of a transmission.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line II in FIG. 1, FIG. 3 is a cross-sectional view taken along line II-II in FIG. 1, and FIG. , a detailed view of the valve drive device, FIG. 5 is a p-v diagram of the four-stroke engine, FIG. 6 is a diagram showing a part of the four-stroke engine, and FIG.
The figure is a diagram showing the relationship between rotation speed and torque. DESCRIPTION OF SYMBOLS 1...Cylinder, 2...Sub-combustion chamber, 3...Piston, 4...Turbo charger, 5...Control unit, 6...Valve drive device. Patent applicant: IsuX Ceramics Research Institute Co., Ltd. Patent attorney: Minoru Tsuji b

Claims (2)

[Claims] (1) An intake port formed in the cylinder cylindrical surface corresponding to the position of the top surface of the piston near bottom dead center, a supercharging means for pressurizing intake air from the intake port into the cylinder, and an exhaust valve provided at the top of the cylinder. an exhaust port whose opening and closing are controlled by the engine; a valve drive means which opens and closes the exhaust valve by electromagnetic force; a fuel control means which variably controls the timing of fuel injection into the combustion chamber; The cycle number is changed every one revolution of the engine output shaft when the number of revolutions of the engine is above a predetermined number of revolutions, and every two revolutions when the number of revolutions is less than a predetermined number of revolutions. variable engine. (2) A rotating electric machine that powers the supercharging means, and a supercharging pressure increasing means that drives the rotating electric machine when the engine rotation speed is lower than the predetermined rotation speed and is below another predetermined rotation speed. The variable cycle number engine according to claim 1, characterized in that the engine has: