JPS63120820A - Control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To control an engine obtaining its high efficiency, low fuel consumption and high output, by providing a valve timing mechanism to be further combined with the combination between a supercharger and a variable compression ratio mechanism and adequately controlling these combinations of the operations. CONSTITUTION:Signals from an operative condition detecting sensor 10 are input to each input interface circuit 21, 23 of an engine control computer (ECU20), and after a CPU24 performs predetermined calculation, the signal of the sensor 10 is fed from an output interface circuit 26 to an equipment of variable timing mechanism 30, variable compression ratio mechanism 40, supercharger 50 and an ignitor 60 or the like of a spark plug 61. Here each zone A-C, respectively corresponding to a light load, intermediate load and a high load, is set. And the ECU20, when, for instance, the zone A is set, respectively controls the variable compression ratio mechanism 40 to high compression ratio, variable valve timing mechanism 30 to the valve timing of small intake amount and the supercharger 50 to be turned off. In this way, an engine obtains its high efficiency, low fuel consumption and high output.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a control device for an internal combustion engine that includes a supercharger, a variable compression ratio mechanism, and a variable valve timing mechanism.

[Prior Art] Conventionally, a supercharger, a variable compression ratio mechanism, and a variable valve timing mechanism are known individually, or two of the three mentioned above are known.
Combinations of the two are known.

However, there is no known internal combustion engine that combines the above three at the same time, and in particular, there seems to be no engine that combines a variable valve timing mechanism with a supercharger and a variable compression ratio mechanism.

[Problems to be Solved by the Invention] Therefore, in an internal combustion engine that simultaneously combines a supercharger, a variable compression ratio mechanism, and a variable valve timing mechanism, how can these operating conditions be controlled in combination? unknown. If the combination of these operations is incorrect, improvements in engine output, efficiency, and fuel efficiency may be hindered.

The present invention further combines a turbocharger and a variable compression ratio mechanism with a valve timing mechanism, and by appropriately controlling the combination of these operations, it is possible to obtain high efficiency, low fuel consumption, and high output of the engine. purpose.

Means for Solving the Problems] To achieve the above object, the control device for an internal combustion engine according to the present invention includes: (a) an internal combustion engine; and (b) a supercharger and a variable supercharger provided for the internal combustion engine. A compression ratio mechanism, a variable valve timing mechanism, (c) an operating condition detection sensor provided for the internal combustion engine, and (d) an operating condition detection sensor that receives input from the map to determine zone A, medium load, which corresponds to light loads. Zone B corresponding to the load and Zone C corresponding to the high load are determined, and when going to zone (A), the variable compression ratio mechanism is set to a high compression ratio, the variable valve timing mechanism is set to a small intake amount valve timing, Control the turbocharger to OFF, and (B) Zone B
(C) In zone C, the variable compression ratio mechanism is controlled to a low compression ratio, the variable valve timing mechanism is controlled to normal intake air amount valve timing, and the supercharger is controlled to supercharging OFF. Consists of an internal combustion engine control device that outputs output and controls the ratio mechanism to a low compression ratio, the variable valve timing Ml+i to a small intake amount valve timing, and the supercharger to supercharging ON. .

[Function] The present invention described above includes a mechanism (variable valve timing mechanism) that can reduce the amount of intake air by increasing pump loss (without relying on a throttle valve), a variable compression ratio mechanism, and a supercharging unit with an intercooler. In an internal combustion engine, it operates as follows.

(a) At light loads, the compression ratio is increased and the amount of intake air is reduced to achieve highly efficient combustion with less air while maintaining a high degree of compression and less pump loss.

(b) During medium-angle loads, the compression ratio is kept normal (for example, around 20, which is about the same as a non-supercharged fixed compression ratio engine), and the amount of intake air is increased. Also, at this time, supercharging is not performed as with light loads. This provides high efficiency without knocking problems during moderate intake air.

(c) At high loads, the compression ratio is normal and intercooled supercharging is performed while the intake air volume is controlled in a decreasing direction, resulting in effective supercharging without knocking while maintaining a high compression ratio, resulting in high efficiency and high output. can be obtained.

Furthermore, when the load is light and low engine output (torque) is desired, it is essential for overall fuel efficiency to efficiently draw in a small amount of air-fuel mixture (air + fuel) and combust it with high efficiency. It is. When intake air is restricted by a typical throttle valve, pumping loss occurs due to negative pressure generated within the intake pipe. In contrast, the intake valve closing timing is advanced or delayed from the most efficient timing. Alternatively, a valve provided in the intake pipe may be used to perform a similar function, thereby shortening the actual intake stroke and controlling the amount of intake air without increasing pumping loss. However, if the volume of the combustion chamber at the top dead center of the piston remains large, the actual compression degree of the air-fuel mixture decreases due to the small amount of intake air, resulting in poor combustion. Here, by using a variable compression ratio mechanism to reduce the volume of the combustion chamber, the actual compression ratio can be kept high, and the overall fuel efficiency under light loads can be significantly increased through low pumping loss and high combustion efficiency. I can do it.

Since supercharging is not necessary for the desired output during medium load, supercharging is turned off and the intake valve timing is optimized to increase the amount of intake air. At this time, the volume of the combustion chamber is increased in accordance with the increase in the amount of intake air to enable operation without problems such as knocking. This condition is considered to be the same as a normal engine without a supercharger.

Supercharging is used for the higher power output desired at higher loads. Here, if the valve timing, combustion chamber volume, etc. remain as they were during the above-mentioned medium load, knocking becomes a problem due to excessive compression of the air-fuel mixture. Here, the combustion chamber volume is usually increased to lower the compression ratio. However, fixedly expanding the combustion chamber volume not only lowers the degree of compression at medium and low loads and reduces efficiency, but even if the combustion chamber volume is expanded with a variable compression ratio mechanism, the expansion ratio will also drop at the same time. This makes it easy to reduce efficiency. Here, by restricting the intake air, the actual intake stroke is reduced and knocking can be suppressed. At this time, the supercharged intake air is cooled by the intercooler, so its pressure and temperature drop, and even if the air-fuel mixture is sent into the cylinder by the boost pressure more than the stroke reduction caused by the intake air restriction, it will not knock and will remain large. Combined with this expansion ratio, it is possible to obtain high output with high combustion efficiency.

The combination of supercharging, variable compression ratio (combustion chamber volume), and variable valve timing (intake restriction) enables highly efficient operation over a wide load range, resulting in low fuel consumption and high output.

Supercharging, variable compression ratio (VCR), and variable valve timing (
This invention aims to achieve high efficiency by combining three types of VVT (VVT), but since VVT is used for both light loads and high loads, the three have been successful.

All three have their own characteristics and advantages, but they also have disadvantages. The combination of VCR and VVT, supercharging and VVT increases the advantages and cancels out the disadvantages. Furthermore, there are very few ideas for realizing VCRs and VVTs, and VVTs have only recently been put into practical use, so they cannot be said to be common, and their effects are not yet satisfactory.

Furthermore, VCRs are extremely difficult, and only a few prototype engines have been released to the public. It is thought that due to the difficulty of each of these, there have been no proposals considering combinations.

[Embodiments] Hereinafter, preferred embodiments of the control device for an internal combustion engine according to the present invention will be described with reference to the drawings.

FIGS. 1 and 2 show the control flow and map of the engine control computer used in the present invention.
3 to 5 show examples and characteristics of a variable valve timing device applicable to the present invention, FIGS. 6 and 7 show an example of a variable compression ratio mechanism applicable to the present invention, and FIGS. FIG. 9 shows a supercharger applicable to the present invention, and FIG. 10 shows a block diagram of these mechanisms and the connection between the supercharger and an engine control computer.

In FIG. 10, 10 indicates an operating condition detection sensor,
For example, it includes a knock sensor 11, an air flow meter 12, a water temperature sensor 13, an intake pipe pressure sensor 14, a throttle position sensor 15, a distributor 16, a starter 17, an air conditioner switch 18, a vehicle speed sensor 19, and the like. A signal from the driving condition detection sensor 10 is input to an engine control computer (ECU) 20. ECU2
0 has an analog signal input interface circuit 21 and a digital signal input interface circuit 23,
The input interface and source circuit 21 is an A/D converter 22
through which it is converted into a digital signal. These input signals are sent to a control processor unit (CPU) 24. The CPU 24 is supplied with power from a constant voltage power supply 25 and performs a deception to be described later. The output of the CPU 24 is sent to each mechanism and device through an output interface circuit 26 to control them.

The output signal from the output interface circuit 26 is the variable valve timing mechanism 30, variable compression ratio machine) l140.

It is sent to the supercharger 50 (supercharger, turbocharger) and also to other equipment, such as the igniter 60 of the spark plug 61.

FIG. 3 shows an example of a variable valve timing mechanism 30 that can be used in the present invention. In the drawing, a rotary valve 33 that rotates in synchronization with the rotation of the engine is disposed downstream of the throttle valve 32 in the intake passage 31 of the engine body 1. By controlling the opening and closing of the rotary valve 33, the opening area of the intake port is controlled as shown in FIG. 4, and the valve timing is substantially controlled. That is, in Figure 4, song 1
1a indicates normal valve timing, the curved line indicates the opening/closing timing of the rotary valve 33, and the hatched area where these two overlap is the intake area. The valve timing is made variable by changing the opening/closing degree and opening/closing timing of the rotary valve 33.

FIG. 5 shows a valve timing mechanism 30 different from that shown in FIG. 3, in which a step motor 34 is used to change the set torsion angle of a camshaft 35, thereby changing the valve timing. . These valve timing mechanisms 30 are individually known mechanisms.

6 and 7 show an example of the variable compression ratio mechanism 40, and as a variable compression ratio mechanism alone,
This is publicly known in 91340 and the like. The variable compression ratio mechanism 40 includes an eccentric bearing 43 rotatably interposed between a piston pin 41 and a connecting rod 42, which is a cylindrical body whose inner and outer circumferences are eccentric with respect to each other.
By moving the lock pin 45 in and out of the lock pin hole 46 formed in the eccentric bearing 43 using hydraulic pressure from 4, the rotation of the eccentric bearing 43 is freed or restrained, and the relative position of the piston 47 with respect to the connecting rod 42 is adjusted. This makes the compression ratio variable.

The compression ratio can be switched between high and low using the eccentric bearing 43.
This is done by switching a hydraulic control valve 48 (see FIG. 10) provided in a passage connected to the hydraulic passage 44.

Pressure oil is supplied to the hydraulic passage from the oil pan through a pump 49.
This is oil pumped up by

The variable compression ratio mechanism may be of a type other than the eccentric bearing type, for example, one that changes the volume of the combustion chamber by moving the piston in and out of the combustion chamber.

8 and 9 show several examples of supercharging [50].

A supercharger 50 in FIG. 8 is an engine with a turbocharger, and a return passage 51 is provided in the intake passage to control the amount of supercharging. The supercharger 50 in FIG. 9 has a waste gate valve 52
For supercharging, a passage bypassing the turbine 50 is provided in the engine exhaust passage 53, and this passage is opened and closed by a wastegate valve 52, and the opening and closing is performed by a diaphragm 55 controlled by a solenoid valve 54. Supercharger 5
0 may be a supercharger in addition to a turbocharger, and the supercharger may be turned on and off by an S/C electromagnetic clutch 56 (see FIG. 10).

The control flow of the engine control computer 20 is shown in FIG. 1, and its map is shown in FIG. Referring to FIG. 1, in block 24a, an operational interrupt is performed, and in block 24b, Q/N and N (Q: intake air pressure, N: engine speed) are input based on the signal from the operating condition sensor 10. Since the engine load is known from Q/N and N, in block 24G, using a map as shown in Fig. 2, it is determined whether the engine load is in zone A corresponding to light load or in zone A corresponding to medium load. However, it is determined whether it is in zone C, which corresponds to high load. The map is determined by engine bench testing and stored. When the engine load is in the A zone, the engine moves along the line of the A zone in FIG.
Turn off supercharging and proceed to block 24m to return. It does not matter where the steps of blocks 24d, 24e, and 24f occur.

When the engine load is medium load, proceed along the 8-zone line from block 24c, change the variable compression ratio to low compression ratio in block 24C7, change the variable valve timing to normal air amount valve timing in block 24h, and block Turn off supercharging at 24i, proceed to block 24m and return. It does not matter where the blocks 24CJ, 24h, and 24i are placed.

When the engine load is high, the engine moves from block 24c along the C zone line, sets the variable compression ratio to a low compression ratio at block 24j, sets the variable valve timing to a valve timing with a small intake air amount at block 24, and sets the variable compression ratio to a low compression ratio at block 24j. Turn on supercharging at 24J, proceed to block 24m and return. It does not matter where the blocks 24j, 24k, and 241 are placed.

These signals are sent to the engine control computer 20
The output signal is sent to each device and mechanism through the output interface circuit 26 (see FIG. 10) and is controlled to satisfy the output signal. Block 24m from interrupt of block 24a
The calculation for returning is repeated at intervals of a fraction or several times the engine rotation.

Next, the operation of the present invention will be explained.

During light loads, the engine control computer 24
This results in a high compression ratio, low intake air amount, and supercharging F. When low engine output (torque) is desired under light loads, it is essential for overall fuel efficiency to efficiently draw in a small amount of air-fuel mixture (air and fuel) and combust it with high efficiency. Supercharging is not necessary when the load is light. When intake air is restricted by a typical throttle valve, pumping loss occurs due to negative pressure generated within the intake pipe. To solve this problem, the intake valve can be closed earlier (Figure 12) or later than the most efficient timing (Figure 11), or by having a valve installed in the intake pipe perform the same function. 3 and 4), the amount of intake air is restricted without increasing the pumping loss by shortening the actual intake stroke. In Figures 11 and 12, the dotted line shows the pumping loss (shaded area) when the valve timing is advanced (Figure 12) or delayed (Figure 11) when the valve timing is advanced (Figure 12) or delayed (Figure 11). , indicating that pumping losses are decreasing. However, if the volume of the combustion chamber at the top dead center of the piston remains large, the actual compression degree of the air-fuel mixture decreases due to the small amount of intake air, resulting in poor combustion. Here, by reducing the volume of the combustion chamber using a variable compression ratio mechanism, it is possible to keep the actual compression ratio high, reduce pumping, and achieve high combustion efficiency, thereby greatly increasing overall fuel efficiency under light loads.

When the load is medium, the compression ratio is low, the air amount is normal, and supercharging is turned off. At medium loads, supercharging is not necessary for the desired output, so supercharging is stopped and the intake valve timing is optimized to increase the amount of intake air. This increases the volume of the combustion chamber and allows operation without problems such as knocking.This condition is considered to be the same as a normal engine without a supercharger.

When the load is high, the compression ratio is low, the valve timing is small, and supercharging is turned on. Supercharging is used for the high power output desired at high loads. Here, if the valve timing, combustion chamber volume, etc. remain as they were during the above-mentioned medium load, knocking becomes a problem due to excessive compression of the air-fuel mixture. Here, the combustion chamber volume is usually increased and the compression ratio is lowered. However, fixedly expanding the combustion chamber volume not only lowers the degree of compression at medium and low loads, reducing efficiency;
Even if the volume of the combustion chamber is expanded using a variable compression ratio mechanism, the expansion ratio is also reduced at the same time, which tends to reduce efficiency. here,
By restricting the intake air, the actual intake stroke is reduced and knocking can be suppressed (see FIG. 13). In Fig. 13, if knocking occurs at point A, the intake valve closes early at point B, which causes the compression ratio to drop as shown by the dotted line, and at point C, the temperature drops and the knocking stops. Even if the boost is very high like in D, the intake valve closes earlier and the compression ratio is lowered, so knocking does not occur.

At this time, the supercharged intake air is cooled by the intercooler, so its pressure and temperature drop, and even if the air-fuel mixture is sent into the cylinder by the boost pressure more than the stroke reduction caused by the intake air restriction, it will not knock and will remain large. Combined with this expansion ratio, it is possible to obtain high output with high combustion efficiency.

The combination of supercharging, variable compression ratio (combustion chamber volume), and variable valve timing (intake restriction) enables highly efficient operation over a wide load range, resulting in low fuel consumption and high mountain performance.

[Effects of the Invention] According to the present invention, high efficiency, low fuel consumption, and high output can be achieved under light load, medium load, and high load conditions by appropriately combining supercharging, variable compression ratio, and variable valve timing. obtain.

[Brief explanation of the drawing]

Fig. 1 is a control block diagram of the engine control computer of the internal combustion engine control device of the present invention, Fig. 2 is a map diagram used for the control shown in Fig. 1, and Fig. 3 is a rotary valve installed in the intake pipe as a variable valve timing mechanism. 4 is a characteristic diagram of the mechanism shown in FIG. 3, FIG. 5 is a sectional view of another example of a variable valve timing mechanism, FIG. 6 is a sectional view of an example of a variable compression ratio mechanism, Figure 7 is the 6th
FIG. 8 is a system diagram of an example of a supercharger; FIG. 9 is a system diagram of another example of a supercharger; FIG. 10 is a block diagram of the control device of the present invention; The figure is a cylinder volume-cylinder pressure diagram showing the reduction in pumping loss due to late intake valve timing. Figure 12 is the cylinder volume-cylinder pressure diagram showing the reduction in pumping loss due to early intake valve timing. Figure 13 is the intake air during supercharging. FIG. 3 is a cylinder volume vs. cylinder pressure diagram showing knock control by restriction. 10......Operating condition detection sensor 20
...... Engine control computer 24 ...... Control processor unit 30 ...... Variable valve timing mechanism 40.・・・・・・・・・・・・Variable compression ratio mechanism 50・・・・・・・・・・・・Supercharger patent Applicant Toyota Motor Corporation Agent Patent attorney Tsuneo Degata (et al.) 1 person)

Claims (1)

[Claims] (1) (a) internal combustion engine; (b) supercharger, variable compression ratio mechanism, and variable valve timing mechanism provided for the internal combustion engine; and (c) operating condition detection provided for the internal combustion engine. (d) Receives input from the operating condition detection sensor and determines zone A corresponding to light load, zone B corresponding to medium load, and zone C corresponding to high load based on the map; (B) Zone B
(C) In zone C, the variable compression ratio mechanism is controlled to a low compression ratio, the variable valve timing mechanism is controlled to normal intake air amount valve timing, and the supercharger is controlled to supercharging OFF. A control device for an internal combustion engine comprising an engine control computer that outputs an output and controls a ratio mechanism to a low compression ratio, a variable valve timing mechanism to a small intake air amount valve timing, and a supercharger to turn on supercharging.