JPH0364648A - Control device of engine with turbo-supercharger - Google Patents

Abstract

PURPOSE:To reduce the temperature of the exhaust gas without increasing the fuel expense and to improve the reliability of the exhaust system by controlling a suction valve to delay its closing time in a high rotation area of the engine compared to a low rotation area, in a high load area of the engine. CONSTITUTION:In a piston 44 installed in a cylinder 42, the upper end 58a of a connecting rod 58 is connected to a piston pin 58a in which a projection 56a to compose a compression ratio converting device 6 is formed at the middle part, and the volume of the combustion chamber 12 (the compression ratio) is different when the projection 56a is positioned at the upper side and when it is positioned at the lower side. A suction port 14 facing the combustion chamber 12 is opened or closed by a suction valve 14a whose closing time is variable by a closing time converting device 52. In this case, in a high load area of the engine, the closing time converting device 52 is controlled to delay the closing time of the suction valve 14a in the higher rotation area compared to the lower rotation area.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a control device for a turbocharged engine.

``Prior Art and Problems to be Solved by the Invention'' Conventionally, in a turbocharged engine, a device for variably controlling the compression ratio of the combustion chamber of the engine is disclosed in Japanese Patent Laid-Open No. 62-282137. In the device disclosed in this publication, when emphasis is placed on engine output, the compression ratio is lowered to prevent knocking, while the supercharging pressure is increased to improve charging efficiency.
When aiming to increase output and place emphasis on engine fuel efficiency, the boost pressure is lowered to prevent knocking, while the compression ratio is increased to improve combustion efficiency and improve fuel efficiency.

The device disclosed in the above publication variably controls the compression ratio of the engine's combustion chamber, but it also controls the compression ratio of intake air introduced into the engine's combustion chamber based on the engine load. It is also possible to control the closing timing of the A device for controlling the compression ratio of the combustion chamber and the closing timing of the intake valve in this manner will be described below.

First, in the low load range of the engine, the compression ratio of the combustion chamber is increased to improve fuel efficiency, and the closing timing of the intake valve is delayed to return a portion of the intake air to the intake passage. , the amount of intake air is reduced to reduce pumping loss. Note that in a low load region, knocking does not occur, so the compression ratio of the combustion chamber can be increased.

On the other hand, in the high load region of the engine, the compression ratio of the combustion chamber is lowered and the intake valve close timing is advanced (here, "early opening" is used to compare with the above-mentioned "late closing"). (refers to the normal closing timing) increases the amount of intake air and increases the torque. Note that in high load regions, the compression ratio of the combustion chamber is lowered to prevent knocking.

As mentioned above, in the device that controls the compression ratio of the combustion chamber and the closing timing of the intake valve, when the engine is in a high load region and the engine is in a high rotation region, the temperature of the exhaust gas increases, and the exhaust system, especially the turbo overflow, is affected. There is a problem that the reliability of the feeder decreases. Note that in order to deal with this problem, it is possible to increase the amount of fuel (make the air-fuel ratio richer), thereby lowering the exhaust gas temperature and maintaining the reliability of the exhaust system. The disadvantage is that the fuel efficiency decreases due to the amount of fuel used.

The purpose of the present invention is to increase torque from low to high engine speeds in the high load area of the engine, while reducing the temperature of exhaust gas in the high engine speeds without increasing fuel consumption. An object of the present invention is to provide a control device for a turbocharged engine that can maintain reliability.

"Means for Solving the Problems" The present invention provides a turbo supercharger, an intake boat that introduces intake air supercharged by the turbo supercharger into a combustion chamber of an engine, and an intake valve that opens and closes the intake boat. a closing timing changing means for changing the closing timing of the intake valve; a compression ratio changing means for changing the compression ratio of the intake air introduced into the combustion chamber; a load detecting means for detecting the load of the engine; control means for controlling the closing timing changing means and compression ratio changing means based on the detection signal from the load detection means, the control means controlling the low engine load based on the detection signal from the load detection means; In the area, compared to the high load area,
A control device for a turbocharged engine configured to increase the compression ratio of a combustion chamber and delay the closing timing of an intake valve, the control device being provided with a rotation speed detection means for detecting the rotation speed of the engine. , the control means is configured to delay the closing timing of the intake valve in a high engine load region and in a high rotation region of the engine, compared to a low rotation region, based on a detection signal from the rotation speed detection means. It is characterized by

"Function" In the present invention, in the high load region of the engine, in the high speed region of the engine, the closing timing of the intake valve is delayed compared to the low speed region, so that a part of the intake air once introduced is diverted to the intake passage. , thereby reducing the amount of intake air. Since the amount of intake air is small in this way, the expansion coefficient of the intake air is large, and therefore the temperature of the exhaust gas is reduced and the reliability of the exhaust system can be maintained.

"Embodiments" Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 1 shows a control device for a turbocharged engine according to an embodiment of the present invention.

In FIG. 1, reference numeral 10 indicates an engine, and the engine 10 has four cylinders. That is, the engine 10 has four combustion chambers 12.12.12.12.

Each combustion chamber 12 is provided with an intake port 14 and an exhaust port 16, and the intake port 14 and exhaust port 16 are opened and closed by an intake valve 14a and an exhaust valve 16a, respectively.

Reference numeral 18 indicates a turbo supercharger, and the turbo supercharger 18
includes a turbine 20 that is rotated by exhaust gas, and a compressor 24 that is coaxially coupled to the turbine 20 via a shaft 22 and rotated by the exhaust turbine 20.

The turbine chamber 26 having the turbine 20 has an exhaust passage 27
It communicates with the exhaust port 16.16.16.16 via the exhaust port 16.16.16.16, and also with another exhaust passage 28, and a waste gate valve 30 is provided between the exhaust passage 27 and the exhaust passage 28. It is located. A compressor chamber 32 with a compressor 24 communicates with the intake boat 14.14.14.14 via an intake passage 34, and also communicates with another intake passage 36.
The intercooler 38 and the throttle valve 4 are located in the middle of the
0 is placed.

and exhaust port 1 of combustion chamber 12.12.12.12
6.16.16.16 Exhaust gas from exhaust passage 27
, the turbine chamber 26, and the exhaust passage 28, the exhaust gas causes the turbine 20 in the turbine chamber 26 to rotate.

As a result, the compressor 24 simultaneously coupled to the turbine 20 is rotated, so that the intake air supercharged by the compressor 24 passes through the intake passage 34 from the intake port 14.14.14.14 to the combustion chamber 12. .12.1
It will be introduced on 2.12.

In the engine 10, the intake valve 14a.

The closing timings of 14a, 14a, and 14a are configured to be changed by a closing timing changing means, and the closing timing changing means will be described below with reference to FIG. 1.2.3.
explain.

Reference numeral 42 indicates a cylinder, and inside the cylinder 42,
A piston 44 is arranged to be slidable in the vertical direction.

In addition, as mentioned above, the reference numeral 12 is a combustion chamber, 14 is an intake port, and 14a is an intake valve. On the other hand, a camshaft 46 that is linked to the engine crankshaft (not shown)
A cam 48 of the camshaft 46 opens and closes the intake valve 14a. In FIG. 3, a shaft 50 interlocked with the engine crankshaft (not shown) and a camshaft 46 are connected by a closing timing changing means 52.
2 meshes with a helical gear portion 50a formed at the end of the shaft 50, a helical gear portion 46a formed at the end of the camshaft 46, and moves in the axial direction by meshing with both gear portions 50a, 46a. a possible annular body 54.

By moving the annular body 54 in the axial direction, the rotational phase of the camshaft 46 relative to the shaft 50 is changed, thereby changing the phase of the cam 48 and changing the closing timing of the intake valve 14a.

Next, the engine 10 has a combustion chamber ■2.12.12.
It has a compression ratio changing means for changing the compression ratio of the intake air introduced into the intake air. Hereinafter, regarding this compression ratio changing means, the first
, 2.4A, and 4B will be explained.

As mentioned above, the reference numeral 42 indicates a cylinder, and a piston 44 is disposed within the cylinder 42 so as to be slidable in the vertical direction. Inside the piston 44 is a piston pin 5.
An upper end 58a of a connecting rod 58 is coupled to the piston pin 56, and a lower end of the connecting rod 58 is pivotally supported by a crankshaft (not shown). Here, the piston pin 56 is not completely cylindrical, but has a compression ratio changing means 60 in its middle part.
A convex portion 56a is formed (4th A, 4B).
(see figure).

Therefore, when the convex part 56a of the piston pin 56 is located upward (Fig. 4Δ) and when it is located downward (Fig. 4'B), the position of the piston 44 is the distance fiL.
In other words, the volume of the combustion chamber 12 is different. Therefore, when the convex portion 56a of the piston pin 56 is located upward (see FIG. 4A), the volume of the combustion chamber 12 is large, so the compression ratio of the intake air introduced into the combustion chamber 12 is small. On the other hand, when the convex portion 56a of the piston pin 56 is located downward (FIG. 4B), the combustion chamber 12
Since the volume of the combustion chamber 12 is small, the compression ratio of the intake air introduced into the combustion chamber 12 is large.

Note that the position of the convex portion 56a is changed by rotating the piston pin 56 while the piston 44 is in operation. here,
The piston pin 56 is rotatable relative to the piston 44. Then, the lock pin 59 disposed in the hole 58b of the connecting rod 58 is engaged with the engagement hole 56b or 56c of the piston pin 56 by the hydraulic pressure of the hydraulic passage 58c, so that the position of the protrusion 56a is maintained. .

Next, reference numeral 62 indicates a control means for controlling the closing timing changing means 52 and the compression ratio changing means 60.

Further, reference numerals 64 and 66 respectively indicate a load detection means for detecting the load of the engine and a rotation speed detection means for detecting the rotation speed of the engine, and the control means 62 receives a detection signal from the load changing means 64 and a rotation speed detection means for detecting the engine rotation speed. Based on the detection signal from the rotation speed changing means 66, the closing timing changing means 52 and the compression ratio changing means 60 are controlled. Note that the control means 62 is supplied with a detection signal from the downstream pressure sensor 68 of the turbocharger 18, and the control means 62 controls the wastegate valve 30 based on the set supercharging pressure.

Hereinafter, the control of the closing timing changing means 52 and the compression ratio changing means 60 by the control means 62 will be explained with reference to the control map shown in FIG.

First, in the low load region of the engine, the compression ratio of the combustion chamber 12 is increased to improve fuel efficiency, and the closing timing of the intake valve 14a is delayed to divert a portion of the intake air that has been introduced into the intake passage 34.
This reduces the amount of intake air and reduces pumping loss. On the other hand, in a high load region of the engine, the compression ratio of the combustion chamber 12 is lowered to prevent knocking, and the closing timing of the intake valve 14a is advanced to increase the amount of intake air and torque.

Further, in a high load region of the engine, in a high rotation region of the engine, the closing timing of the intake valve 14a is delayed compared to a low rotation region, and a portion of the intake air once introduced is diverted to the intake passage 3.
4, thereby reducing the intake air amount. Since the amount of intake air is small in this way, the expansion rate of the intake air is large,
Therefore, the temperature of the exhaust gas is reduced and the reliability of the exhaust system can be maintained.

"Effects of the Invention" As explained above, according to the present invention, in the high load region of the engine, the torque is increased from the low rotation region to the high rotation region, while in the high rotation region, the fuel consumption is not increased. The reliability of the exhaust system can be maintained by lowering the temperature of the exhaust gas.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the configuration of a control device for a turbocharged engine according to an embodiment of the present invention, FIG. 2 is a sectional view of the engine, and FIG. 4A, 4B
5 is a configuration explanatory diagram of a compression ratio changing means, and FIG. 5 is a control map diagram of a turbocharged engine according to an embodiment of the present invention. 10... Engine, 12.12.12.12... Combustion chamber, 14.1
4.14.14... Intake port, 14a, 14
a, 14aS 14a----・Intake valve, 16.16
．． 16.16...exhaust port, 16a, 16
a, 16 a, 16 a...Exhaust valve...
...Turbocharger, ...Exhaust passage, ...Intake passage, ...Cylinder, ...Piston, ...Cam Shaft, ...Cam, ...Shaft, ...Close timing changing means, ...Piston pin, ...Connecting rod... ...compression ratio changing means, ...control means, ...load detection means, ...rotation speed detection means. Figure 3 Figure 5 Rotation speed

Claims (1)

[Claims] A turbo supercharger, an intake port that introduces intake air supercharged by the turbo supercharger into a combustion chamber of an engine, an intake valve that opens and closes the intake port, and an intake valve that opens and closes the intake valve. Closing timing changing means for changing the timing; compression ratio changing means for changing the compression ratio of intake air introduced into the combustion chamber; load detecting means for detecting engine load; and detection from the load detecting means. control means for controlling the closing timing changing means and the compression ratio changing means based on a signal, the control means controlling the engine in a low load area and in a high load area based on the detection signal from the load detection means. Compared to,
A control device for a turbocharged engine configured to increase the compression ratio of a combustion chamber and delay the closing timing of an intake valve, the control device being provided with a rotation speed detection means for detecting the rotation speed of the engine. , the control means is configured to delay the closing timing of the intake valve in a high engine load region and in a high rotation region of the engine, compared to a low rotation region, based on a detection signal from the rotation speed detection means. A control device for a turbocharged engine.