JPH0526050A - Control device for two-four cycle switching engine - Google Patents

Abstract

PURPOSE:To easily sit a cycle switching point in an engine in which an intake port on the lower part of a cylinder or an intake valve on the cylinder top part is opened or closed according to 2 or 4 cycles, 2 or 4-cycle operation is conducted by opening/closing intake and exhaust valves and switching the timing of fuel injection. CONSTITUTION:The 2-cycle operation of an engine is possible only when intake boost pressure is higher than exhaust pressure. Therefore, on the basis of the comparison of the detected pressures by a boost pressure sensor 26 provided on the intake pipe 22 of an engine 1 and an exhaust pressure sensor 72 provided on an exhaust passage, the engine is switched to 2 cycle and operated at the point of time where the intake boost pressure is higher in the comparison according to the operating state detected by an engine rotating speed sensor 17 and an accelerator sensor 71.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a 2-4 cycle switching engine which operates by switching between 2 cycles or 4 cycles depending on the rotation and load of the engine.

[0002]

2. Description of the Related Art A normal engine is a two-stroke engine that performs intake, compression, explosion, and exhaust processes during two strokes of a reciprocating piston, that is, one revolution of the crankshaft, and four strokes of the piston, that is, the crankshaft. It is roughly classified into a four-cycle engine that performs the above-mentioned four processes during two revolutions.

In a uniflow type two-cycle engine, an intake port is arranged below the cylinder liner, and air sucked and exhausted at the same time by air sent under pressure near the bottom dead center of the piston. Since the fuel explodes, there is an advantage that the output shaft rotation fluctuation is small and high torque can be generated. On the other hand, in the 4-cycle engine, the intake and the exhaust are performed in separate strokes of the piston, which is effective. Fuel is used to improve fuel efficiency.

[0004]

Therefore, if one engine is switched to two cycles or four cycles and the operation that takes advantage of each of them is carried out, an engine with high output and good efficiency can be obtained. There is a drawback that there are many difficulties in setting.

The present invention has been made in view of such a problem, and its object is to pay attention to the relationship between the intake boost pressure and the exhaust pressure in a 2-cycle engine when setting the cycle of the 2-4 cycle switching engine. It is an object of the present invention to provide a control device for a 2-4 cycle switching engine that easily sets the switching time point.

[0006]

In order to achieve the above object, according to the present invention, a turbocharger having a rotating electric machine for urging a supercharging operation is arranged, and an intake port provided at a lower portion of a cylinder is closed. And a closing of an intake valve arranged at the top of the cylinder according to the cycle switching, and the cycle switching is performed by changing the timings of opening and closing the intake valve and the exhaust valve and fuel injection. In the control device, intake pressure detecting means for detecting the intake boost pressure of the engine, exhaust pressure detecting means for detecting the exhaust pressure, and switching for performing cycle switching in accordance with the operating state of the engine based on signals from these detecting means. There is provided a control device for a 2-4 cycle switching engine having control means.

[0007]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

In the figure, reference numeral 1 denotes an engine, a cylinder head 11 is provided with a sub chamber 12 made of a heat insulating material, and fuel supplied from an injection nozzle 13 arranged in the sub chamber 12 and the cylinder head 11 are provided. Intake port 16 penetrating below the intake port 14 or cylinder liner 15
The vehicle is driven in four cycles or two cycles by the combustion energy with the air sent from the vehicle.

Reference numeral 2 denotes an intake valve provided at the intake port 14, which is controlled to open / close at a predetermined timing by an electromagnetic valve mechanism (not shown) when the engine 1 is operating for four cycles. An exhaust valve provided with an electromagnetic valve mechanism is arranged behind the. The intake valve 14
Is closed during two cycles of operation.

A turbocharger 3 is provided with a turbine driven by the energy of the exhaust gas that has passed through the exhaust manifold 32 via the opened exhaust valve, and a compressor driven by the turbine torque. It supplies compressed air to the engine 1 as a supercharger. At the 4th cycle, the intake port 1 is supplied through the intake pipe 22.
It is configured to be supplied from the intake port 16 through the connecting pipe 23 branched from the intake pipe 22 in the second cycle. An intake shutter 24 that is closed during four cycles is attached to the intake port 16, and the intake shutter 24 moves along the outer periphery of the cylinder liner 15 by energization of the electromagnetic coil 25.
Control the opening and closing of. Further, a rotary electric machine (TCG) 31 serving as a motor-generator is arranged on a rotary shaft between the turbine of the turbocharger 3 and the compressor, and operates as a generator when the turbine torque due to exhaust energy is strong. When the engine is accelerated or when the engine speed is low and the load is high, it is electrically driven by the electric power from the battery 61 via a controller, which will be described later, to assist the supercharge operation of the turbocharger 3.

Reference numeral 4 denotes a turbine generator, which is driven by surplus energy of the exhaust gas discharged from the turbocharger 3 to generate electric power.
The electric energy recovered by the rotary electric machine 31 is
Is transmitted to the controller to be described later together with the output at the time of power generation operation.

Reference numeral 5 denotes an electric motor connected to the crankshaft of the engine 1. The electric motor 5 is driven by the output of the rotary electric machine 31 during power generation and the electric power of the turbine generator 4 to increase the output of the engine 1. The supplied power is controlled by the controller 6.

The controller 6 comprises a microcomputer, a central control unit for performing arithmetic processing, various memories for storing arithmetic processing procedures and control procedures, input / output circuits, and the rotating electric machine 31 and the turbine generator 4 during power generation operation. It is provided with a high-power circuit or the like that can add the output from the electric motor 5 to convert the electric power to drive the electric motor 5 and supply the electric power from the battery 61 to the rotating electric machine 31. The engine rotation sensor 17 for detecting the crankshaft rotation speed, the boost pressure sensor 26 for detecting the boost pressure, the exhaust pressure sensor 72 for detecting the exhaust pressure, the accelerator sensor 71 for detecting the depression amount of the accelerator pedal 7, and the like. When the detection signal is input, a predetermined process is performed, and an appropriate command is issued to the power control from the high-power circuit and the injection nozzle 13, the electromagnetic coil 25, and the like.

The engine in this embodiment is constructed as an adiabatic engine, and in addition to the sub chamber 12 described above, an insulating material is used not only for the top of the piston or for a part of the cylinder liner, but to reduce combustion energy. Emissions are suppressed.

FIG. 2 is a process flow chart showing an example of the operation of this embodiment. Next, the operation of this embodiment will be described with reference to this figure.

First, in step 1, the engine speed N is determined based on the detection signal from the engine speed sensor 17, and if the engine speed is lower than a predetermined speed Na, step 2 is performed.
If the rotation speed is high, the process proceeds to step 5, and in step 5, the accelerator opening, that is, the engine load L is read by the signal from the accelerator sensor 71.

Next, at step 6, the boost pressure Pa to be supplied corresponding to the accelerator opening La is calculated,
This value Pa and the detected value Pb from the boost pressure sensor 26 in step 7 are compared in step 8. As a result,
If the calculated value of Pa is much larger than Pb, the process proceeds from step 9 to step 9, but if not, step 1
Moving to 6, the exhaust pressure Pe is obtained from the signal from the exhaust pressure sensor 72.

Then, in step 17, the exhaust pressure Pe and
The intake boost pressure Pb detected in step 7 is compared, and when the boost pressure Pb is large, two-cycle operation is possible, so the routine proceeds to step 18, where the electromagnetic coil 25 is instructed to move the intake shutter 24 to intake air. The port 16 is opened and the intake valve 2 of the cylinder head 11 is closed,
The opening / closing operation of the exhaust valve 21 and the timing of fuel injection from the injection nozzle 13 are controlled for two cycles, and the process proceeds to step 19 to cause the rotating electric machine (TCG) 31 and the turbine generator 4 to generate electric power to supply electric power to the electric motor 5. Supply and energize the engine torque.

On the other hand, when the exhaust pressure Pe is higher than the boost pressure Pb in step 17, the two-cycle operation becomes impossible, so the routine proceeds to step 20, where the electromagnetic coil 25 is instructed to control the closing of the intake port by the intake shutter 24. The operation of controlling the fuel injection from the intake valve 2, the exhaust valve 21, and the injection nozzle 13 at the timing for 4 cycles to be a 4-cycle operation, and making the electric motor 5 power-run by the power output from the rotating electric machine 31 and the turbine generator 4. To perform.

Further, P is calculated by the calculation in step 8 described above.
When the value of a is much larger than the detected value Pb and the routine proceeds to step 9, the rotary electric machine 31 is electrically driven by the electric power of the battery 61 so as to increase the intake boost pressure. Next, in step 10, the electromagnetic shutter 25 is operated to operate the intake shutter 24 to open the intake port 16, the intake valve 2 is closed, the exhaust valve 21 is opened / closed, and the fuel injection timing from the injection nozzle 13 is used for two cycles. The boost pressure sensor 26 detects the boost pressure Pc boosted by the boost pressure sensor 26 in step S11.

In the next step 12, the boost pressure Pc
When the boost pressure Pc is large, the power supplied to the rotary electric machine 31 is reduced in step 13, and when the boost pressure Pc is small, the process proceeds to step 14 to supply power. In step 15, the boost pressure value Pc is compared with the boost pressure value Pc, and in step 15, the boost pressure value Pc is compared with the boost pressure value Pc. However, in the case of no, the process returns to step 14 and the power supply to the rotary electric machine 31 is controlled to increase.

When the engine speed is low in step 1 and the process proceeds to step 2, it is checked whether or not the starter is on, and if it is on, it is 4 as described in step 20 above. The control for the cycle operation is performed, the electric rotating machine 31 is electrically driven to urge the supercharging operation of the turbocharger 3, and the flow from step 1 is repeated.

Although the present invention has been described with reference to the above embodiments, various modifications can be made within the scope of the gist of the present invention, and these modifications are not excluded from the scope of the present invention.

[0025]

As described above, according to the present invention, the intake boost pressure of the engine is compared with the exhaust pressure, and when the intake boost pressure is high, the scavenging pressure required for the two-cycle engine becomes high. Since the 2-cycle operation is performed at the time point, there is an advantage that the cycle switching of the engine that can be switched to 2 cycles or 4 cycles can be easily set
Particularly in an adiabatic engine, the temperature of the exhaust gas rises quickly, so the condition that the intake boost pressure becomes higher than the exhaust pressure occurs earlier.

[Brief description of drawings]

FIG. 1 is a configuration block diagram showing an embodiment of the present invention.

FIG. 2 is a process flow chart showing an example of the operation of the present embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Intake valve 3 ... Turbocharger 4 ... Turbine generator 5 ... Electric motor 6 ... Controller 13 ... Injection nozzle 16 ... Intake port 17 ... Engine rotation sensor 24 ... Intake shutter 25 ... Electromagnetic coil 26 ... Boost pressure sensor 31 ... Rotating electric machine (TCG)

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location F02B 37/00 302 B 7713-3G

Claims (1)

What is claimed is: 1. A turbocharger having a rotating electric machine for urging a supercharging operation is arranged, and an intake port provided at a lower portion of a cylinder and an intake valve closed at a top portion of the cylinder are closed according to cycle switching. Control unit for a 2-4 cycle switching engine, which controls the opening and closing of the intake valve and the exhaust valve and changes the timing of fuel injection to perform cycle switching, and intake pressure detecting means for detecting an intake boost pressure of the engine. An exhaust pressure detecting means for detecting the exhaust pressure, and a switching control means for performing cycle switching according to the operating state of the engine based on signals from these detecting means. Control device.