JP2742825B2 - Variable cycle engine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a variable cycle engine that switches between two-cycle operation and four-cycle operation in accordance with changes in engine speed and load.

(Prior art) A normal piston reciprocating engine has one reciprocation of a piston,
That is, a two-cycle engine that performs the intake, compression, explosion, and exhaust strokes with one revolution of the crankshaft, and a four-cycle engine that performs the four strokes during two reciprocations of the piston, that is, two revolutions of the crankshaft. Is done.

In a two-stroke cycle engine, an intake port (intake port) is arranged below the cylinder sleeve, and is opened when the piston descends.
Intake and exhaust are performed simultaneously in parallel, and one of the crankshafts
Since the explosion is performed every rotation, the rotation fluctuation of the output shaft is small and a high torque can be generated.

On the other hand, in the four-cycle engine, the intake and exhaust are performed in independent strokes, so that the gas is sufficiently exchanged. Therefore, there is an advantage that the fuel consumption rate is small especially when the engine rotation speed is high, as compared with the two-cycle engine.

(Problems to be Solved by the Invention) By the way, when one engine is freely changed between two-cycle operation and four-cycle operation and the operation adapted to each characteristic is performed, it is used during the two-cycle operation as described above. In the four-cycle operation, the intake port opens when the piston descends, and the inside and outside of the cylinder communicate with each other, which causes a problem that the operation of the engine is hindered.

Further, even during the two-cycle operation, if the opening area of the intake port is increased to increase the efficiency of intake from the intake port, the opening timing of the intake port is advanced, the expansion stroke is shortened, and the output decreases and the speed during high-speed rotation is reduced. Troubles such as intake blow-back occur.

Accordingly, the applicant of the present application has provided a sleeve valve for opening and closing the intake port on the outer peripheral surface of the cylinder sleeve, and driving the sleeve valve by an electromagnetic solenoid through a mechanism such as a link to open and close the intake port as needed. A variable engine has already been filed as Japanese Patent Application No. 1-112507.

However, when the sleeve valve is driven by an electromagnetic solenoid through a mechanism such as a link as described above, the driving device becomes complicated, and the response speed is slow due to the completion of the driving mechanism and play in the moving part. is there.

Further, since the intake port opening during the two-cycle operation is constant, gas exchange is insufficient at high speed and high load, and the expansion stroke is short at low speed partial load, resulting in insufficient output.

The present invention has been made in view of such a problem, and an object of the present invention is to provide an agile response when switching between two-cycle operation and four-cycle operation in accordance with changes in engine speed and load, and to achieve a two-cycle operation. An object of the present invention is to provide a variable cycle engine capable of variably controlling an intake port during operation.

(Means for Solving the Problems) According to the present invention, in a cycle variable engine that switches from four-cycle operation to two-cycle operation when the engine state is equal to or lower than a predetermined rotation speed and equal to or higher than a predetermined load, the upper surface of the cylinder is opened and closed. The intake and exhaust valves, which can freely control the pressure, and an intake port formed in the lower cylinder surface of the cylinder sleeve for inhaling intake air, and an opening portion connected to the intake port and having a different opening area on the cylinder surface, the outer periphery of the cylinder sleeve. An annular sleeve valve that is loosely fitted and opens and closes the opening, and rotates the sleeve valve when the rotation speed is equal to or less than a predetermined rotation speed that is lower than the predetermined rotation speed and is equal to or higher than a predetermined load that is higher than the predetermined load. Opening the opening, stopping the operation of the intake valve, rotating the sleeve valve when the number of rotations and the load are equal to or higher than a predetermined value, closing the opening, and closing the intake valve; A variable cycle engine having control means for a sleeve valve and an intake valve for opening and closing the operation of the engine.

(Operation) In the present invention, when the engine speed is equal to or lower than the predetermined speed and the engine load is equal to or higher than the predetermined load, the operation cycle of the engine is switched from 4 cycles to 2 cycles.
During the two-cycle operation, when the engine speed is equal to or lower than a set speed at which the engine speed is lower than the predetermined speed, and when the engine load is equal to or lower than a set load at which the engine load is lower than the predetermined load, the opening of the intake port is performed. Reduce the area and move the open timing to the bottom dead center side.

(Example) Next, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an overall configuration diagram showing one embodiment of the present invention.

Reference numeral 1 denotes an engine cylinder. A cylinder sleeve 11 is provided on the inner wall of the cylinder 1. A plurality of cylinder sleeves 11 are provided on the peripheral wall of the cylinder sleeve 11 corresponding to the vicinity of the upper end of the piston head 21 at the bottom dead center position of the piston 2. Intake port 12
Are drilled.

The intake ports 12 are inclined and open so that the intake air from the intake pipe 13 is swirled and taken into the cylinder 1.

Reference numeral 3 denotes a sleeve valve which covers the opening of the intake port 12 described above, is fitted on the outer periphery of the cylinder sleeve 11, and is arranged in a belt-like manner so as to slide.

An opening 31 corresponding to the intake port 12 and an opening 32 to be described later are formed, and when the cylinder 31 is rotated by a predetermined angle in the circumferential direction of the outer periphery, the opening 31 or the opening 32 and the intake port 12 are And the intake pipe 13 and cylinder 1
Communicate with the inside. In addition, when it does not match any of the openings 31 and 32, the intake port 12 is closed and the intake pipe is closed.
13 and the inside of the cylinder 1 are isolated.

Reference numeral 4 denotes a fixed electromagnet serving as a rotating means of the sleeve valve,
Details will be described later.

Reference numeral 5 denotes an intake valve which is provided above the cylinder 1 and guides intake air from the intake passage 14 to the cylinder 1 in accordance with the operation of the engine. The opening / closing drive of the intake valve 5 is controlled by an electromagnetic valve actuator 51 disposed at the top.

Reference numeral 6 denotes an exhaust valve provided above the cylinder 1, which guides exhaust gas in an exhaust process of the engine to an exhaust path 15. The opening / closing drive of the exhaust valve 6 is controlled by an electromagnetic valve actuator 61 disposed at the top.

The electromagnetic valve actuator 51 and the electromagnetic valve actuator 61 each include a movable magnetic pole connected to the intake valve 5 and the exhaust valve 6, and a fixed electromagnet fixed to the engine side. The intake and exhaust valves 5 and 6 are driven by the electromagnetic force acting between the two. The control command to the fixed electromagnet is issued from a controller 8 described later.

Reference numeral 7 denotes a turbocharger, which internally includes a turbine 7a, a rotating electric machine 70, and a compressor 7b on a coaxial 7c as shown in FIG. The compressor 7c is driven by the torque of the turbine 7a driven by the energy of the exhaust gas discharged from the exhaust passage 15, and the intake passage 13 is operated when operating as a two-cycle engine, and the intake air is operated when operating as a four-cycle engine. The supercharged air is supplied to the cylinder 1 via the passage 14.

If exhaust energy is insufficient at low speed in accordance with the operating state of the engine, electric power is supplied to the rotating electric machine 70 to perform power running, thereby energizing the supercharging operation of the compressor 76. When the exhaust energy from the engine is large, the rotating electric machine 70 operates as a generator, and the generated electric power is supplied to the battery 80 and the like.

Reference numeral 81 denotes a rotation sensor which measures the rotation speed of the crankshaft to detect the rotation speed of the engine.

A load sensor 82 detects an engine load by detecting, for example, a fuel supply amount to the engine.

Reference numeral 83 denotes a position sensor which detects a crank angle by detecting a crank angle. Signals from these sensors are input to the controller 8.

The controller 8 includes a microcomputer, and includes a central control device for performing arithmetic processing, various memories for storing arithmetic processing procedures and control procedures, input / output ports, and the like, and receives signals from the various sensors. And predetermined arithmetic processing is performed, and control commands are issued to the fixed electromagnet 4, the electromagnetic valve actuator 51, the electromagnetic valve actuator 61, the rotating electric machine of the turbocharger 7, and the like based on the stored control procedure. .

Next, the relationship between the sleeve valve 3 and the intake port 12 will be further described with reference to FIG.

 FIG. 2 is a partially developed view of the sleeve valve.

In the figure, reference numeral 12 denotes one of the plurality of intake ports 12 for simplicity of description, but the same applies to the other intake ports 12.

The sleeve valve 3 is provided at a position covering the intake port 12, but is displaced downward in this figure. Further, the fixed electromagnet 4 also faces the side surface of the sleeve valve 3, but is shown displaced in this figure.

This figure shows a state in which the intake port 12 is closed by the sleeve valve 3. An opening 31 is formed in the peripheral surface of the sleeve valve 3 at a position separated by a distance P in the closed state. The opening 31 is formed in substantially the same shape as the intake port 12. An opening 32 is formed at a position further away from the opening 31 by a distance P. The opening area of the opening 32 is half of the opening area of the intake port 12, and the upper half in the drawing is closed.

It should be noted that the above configuration increases and increases the stroke work in the cylinder 1, and thus improves engine efficiency.

On the peripheral surface of the sleeve valve 3, a permanent magnet 33 having a magnetic pole in the circumferential direction is further provided. The magnetic poles of the permanent magnet 33 are, for example, N pole on the left side of the figure and S pole on the right side.

The fixed electromagnet 4 faces the permanent magnet 33. The fixed electromagnet 4 includes five fixed magnetic poles 41 to 45 provided at a distance P from each other and exciting coils 46 to 49 provided between the fixed magnetic poles. And each excitation coil
46 to 49 are supplied with electric power from the controller 8 to excite the fixed magnetic poles 41 to 45.

In the state shown in the figure, the excitation coil 46 and the excitation coil 47 are energized, and the fixed magnetic pole 41 is excited to the N pole and the fixed magnetic pole 43 is excited to the S pole.

From this state, when the excitation coil 46 is stopped and the excitation coil 48 is energized to excite the fixed magnetic pole 42 to the N pole and the fixed magnetic pole 44 to the S pole, the permanent magnet 33 moves to the left side of the drawing. And the distance P. Then, the opening 31 matches the intake port 12, and the intake port 12 is fully opened.

Further, in this state, the energization of the excitation coil 47 is stopped, and the excitation coil 49 is energized to excite the fixed magnetic pole 43 to the N pole and the fixed magnetic pole 45 to the S pole. To the distance P. Then this time the opening
32 coincides with the intake port 12, the intake port 12 is in a half-open state, and the opening timing further moves to the bottom dead center side.

Next, the operation of the present embodiment configured as described above will be described.

FIG. 3 is a characteristic diagram showing the relationship between the engine speed and load according to the present invention.

In the figure, the horizontal axis represents the engine speed N, and the vertical axis represents the engine load L. In addition, I indicates characteristics during two-cycle operation, and II indicates characteristics during four-cycle operation. Further, regions A, B, and C are regions that are operated in two cycles, and region D is a region that is operated in four cycles.

FIG. 4 is a flowchart showing the operation of the engine according to the present invention.

The controller 8 reads the engine load L by the load sensor 82 and the engine speed N by the rotation sensor 81 in Steps 1 and 2.

In step 3, it is determined whether to operate in four cycles or two cycles. That is, in the region where the engine speed N is lower than the predetermined speed Nc and the engine load L is higher than the predetermined load Lc, two-cycle operation is performed, and the engine speed L becomes higher than the predetermined speed Nc. In a region where the load is lower than a predetermined load Lc, the operation is performed for four cycles.

When it is determined that the operation is the four-cycle operation, the process proceeds to step 8, and in steps 8, 9, and 10, the intake valve 5 is operated.
And the exhaust valve 6 are operated for four cycles, and the intake port 12
Is normally closed. This operating state corresponds to the area D in FIG.

If it is determined in step 3 that the operation is a two-cycle operation, in step 4 the engine speed N input in step 2 is determined.
Is compared with a predetermined rotation speed N1, and if N> N1, the process proceeds to step 5, and if N ≦ N1, the process proceeds to step 11.

In step 5, the state of energization of the fixed electromagnet 4 is changed so that the intake port 12 and the opening 31 match.

Then, at step 6, the electromagnetic valve actuator 51
The output of the control signal to is stopped, and the operation of the intake valve 5 is stopped.

Then, in step 7, the electromagnetic valve actuator
The control signal output to 61 is changed to the operation mode at the time of high rotation at 2 cycles. Note that the operation state is the area A in FIG.
Is equivalent to

The flow from step 4 to step 11
At 11, the engine load L input at step 1 is compared with a predetermined load L1, and if L> L1, the routine proceeds to step 12, where L
If ≤L1, go to step 15.

In step 12, the energization state of the fixed electromagnet 4 is changed so that the intake port 12 and the opening 31 coincide with each other as in step 5.

Then, at step 13, the electromagnetic valve actuator 51
The output of the control signal to is stopped, and the operation of the intake valve 5 is stopped.

Then, in step 14, the electromagnetic valve actuator
The control signal output to 61 is changed to the operation mode at the time of low rotation at 2 cycles. The operating state is indicated by a region B in FIG.
Is equivalent to

The flow from step 11 to step 15
At 15, the state of energization of the fixed electromagnet 4 is changed so that the intake port 12 matches the opening 32.

Then, at step 16, the electromagnetic valve actuator 51
The output of the control signal to is stopped, and the operation of the intake valve 5 is stopped.

Then, in step 17, the electromagnetic valve actuator
The control signal output to 61 is changed to the operation mode at the time of low rotation at 2 cycles. Note that the operation state is the area C in FIG.
Is equivalent to

When steps 7, 10, 10, and 17 are completed, the process returns to step 1.

The engine according to the present invention may use alcohol fuel such as methanol as the fuel. However, alcohol fuel has a large latent heat of vaporization, and thus has poor startability in a cold state.

Therefore, a temperature sensor for detecting the temperature inside the combustion chamber is provided, and when the temperature of the combustion chamber detected by the temperature sensor is equal to or lower than a predetermined temperature, the engine speed is determined when the cycle number is determined in step 3 described above. In addition, two cycles can be selected regardless of the engine load and the engine load, and the control for improving the startability can be performed.

As described above, the present invention has been described in detail by the above embodiments, but various modifications are possible within the scope of the gist of the present invention,
These modifications are not excluded from the scope of the present invention.

(Effect of the Invention) According to the present invention, when the engine speed is equal to or lower than a predetermined speed and the engine load is equal to or higher than a predetermined load, the operation cycle of the engine is switched from four cycles to two cycles,
Further, when the two-cycle operation is performed and the engine speed is equal to or less than a set speed that is lower than the predetermined speed,
And, when the engine load is equal to or less than the set load which is lower than the predetermined load, the opening area of the intake port is reduced and the opening timing is moved to the bottom dead center side, so that the engine speed and the load change according to the engine speed. The compression ratio can be varied, improving engine efficiency and increasing power.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention, FIG. 2 is a partial developed view of a sleeve valve, FIG. 3 is a characteristic diagram showing a relationship between the engine speed and load according to the present invention, FIG. 4 is a flowchart showing the operation of the engine according to the present invention, and FIG.
The figure is a detailed sectional view of the turbocharger. 1 ... cylinder, 2 ... piston, 3 ... sleeve valve,
4 ... fixed electromagnet, 5 ... intake valve, 6 ... exhaust valve, 7 ... turbocharger, 8 ... controller, 11
…… Cylinder sleeve, 12 …… Intake port, 13 ・ 14 ……
Intake pipe, 33 ... permanent magnet.

Claims (3)

(57) [Claims] An intake and exhaust valve capable of freely controlling the opening and closing of an upper surface of a cylinder in a variable cycle engine that switches from four-cycle operation to two-cycle operation when an engine state is a predetermined number of revolutions or less and a predetermined load or more. An intake port formed in the lower cylinder surface of the cylinder sleeve for inhaling intake air, and an annular portion connected to the intake port and having an opening having a different opening area in the cylindrical surface and loosely fitted to the outer periphery of the cylinder sleeve to open and close the opening. A sleeve valve, and when the rotation speed is equal to or lower than a set rotation speed lower than the predetermined rotation speed and equal to or higher than a set load higher than the predetermined load, the sleeve valve is rotated to open the opening, and the intake valve is opened. The operation of the sleeve valve is stopped when the rotation speed and the load are equal to or higher than a predetermined value, the sleeve valve is rotated, the opening is closed, and the operation of the intake valve is opened and closed. Cycle variable engine characterized by having a control means of the pre-intake valve. 2. When the engine speed is lower than a predetermined value and the load is lower than a predetermined value, the operation of the intake valve is stopped, and the operation of the sleeve valve is reduced to a value smaller than the area of the opening. 3. The variable cycle engine according to claim 1, further comprising control means. 3. The sleeve valve according to claim 1, wherein the sleeve valve is rotated by an electromagnetic force acting between a permanent magnet connected to the sleeve valve and a fixed electromagnet facing the permanent magnet. 1) The variable cycle engine according to the above.