JPH06248988A - Variable compression ratio device for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent any knocking in an engine and to improve fuel consumption by detecting the optimum compression ratio based on the blend rate of emulsion fuel and an engine operation load and setting the optimum ignition timing suitable for the compression ratio. CONSTITUTION:In an engine 1 having a variable compression ratio device 2, a compression ratio is switched to two stages of a high level and a low level through the feed of oil pressure from an oil pressure circuit 3. The oil pressure circuit 3 is controlled by means of a parameter being the number of revolutions of an engine, an engine load, and a blend rate of gasoline and methanol in fuel, based on the optimum compression ratio computed by an ECU 4. Further, after a compression ratio is switched by the variable compression ratio device 2, the optimum ignition timing is calculated by the ECU 4 from an engine load and an ignition timing signal is transmitted to an ignition coil 5. A blend rate of gasoline and alcohol in fuel is measured by a blend rate sensor 10 to input the result to the ECU 4. This constitution causes improvement of fuel consumption as knocking at an engine is prevented from occurring.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable compression ratio device for an internal combustion engine which uses a mixed fuel such as gasoline and methanol having different physical properties.

[0002]

2. Description of the Related Art Conventionally, as shown in Japanese Utility Model Laid-Open No. 3-127053, a compression ratio is set to a low compression ratio in a high load range or a high engine speed range which is larger than the medium load range of the engine to prevent knocking. In order to improve the fuel efficiency etc. by increasing the thermal efficiency in the operating range of medium load or less while preventing it from occurring, various variable compression ratio devices that set the compression ratio to a high compression ratio within the range where knocking does not occur are proposed. Has been done.

[0003]

Since such a conventional variable compression ratio device is applied to an engine using one type of fuel such as gasoline, switching of the compression ratio is judged only by the operating load state of the engine. There were many things. However, recently, an engine using a mixed fuel (e.g., emulsion fuel) in which a plurality of types of fuels having different physical properties are mixed has been developed in order to reduce the combustion temperature and the exhaust gas.

When an emulsion fuel is used in a variable compression ratio device in which compression ratio switching is set for an engine using a single fuel (gasoline / light oil), the variable compression ratio device can be operated without knocking. Despite being in the operating range, when the operation switching range when using a single fuel is reached, the compression ratio switches from high to low, narrowing the operating range in which it can operate at a high compression ratio. Become. Therefore, it becomes impossible to improve the fuel consumption even though the emulsion fuel is used. On the contrary, when a single fuel is used for the variable compression ratio device that sets the compression ratio switching for the engine that uses emulsion fuel, in the operating range where knocking does not occur when emulsion fuel is used. However, in reality, a problem such as knocking occurs.

The present invention is intended to solve the above problems,
By setting the optimum high / low compression ratio switching timing according to the blend ratio of the emulsion fuel and the engine operating load condition, and determining the optimum ignition timing in the operating load condition corresponding to the blend ratio, the emulsion fuel The purpose is to improve fuel efficiency while preventing knocking in the engine using.

[0006]

SUMMARY OF THE INVENTION The present invention is to achieve the above object, and is a variable compression ratio means for varying the compression ratio of an internal combustion engine and an ignition timing switching means for varying the ignition timing of the internal combustion engine. A blend ratio sensor for detecting a mixture ratio of a plurality of types of fuel having different physical properties supplied to the internal combustion engine, an operating load state detecting means for detecting an operating load state of the internal combustion engine, the blend ratio and the operation A compression ratio control means for detecting the optimum compression ratio on the basis of the load condition and outputting a compression ratio switching signal to the variable compression ratio means, and an internal combustion engine for the internal combustion engine on the basis of the operating load condition and the compression ratio switching signal. Ignition timing control means for detecting the optimum ignition timing and outputting the ignition timing switching signal to the ignition timing switching means.

[0007]

According to the present invention, in an engine equipped with a variable compression ratio device to which emulsion fuel is applied, the compression ratio is switched based on the engine operating load state according to the blend ratio of the emulsion fuel supplied to the internal combustion engine, and the operation thereof is performed. By setting the optimum ignition timing for the load state, it is possible to improve fuel efficiency while preventing knocking in an engine equipped with a variable compression ratio device using emulsion fuel.

[0008]

Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 is a configuration diagram showing a system that employs a variable compression ratio device for an engine and switches the compression ratio under operating load conditions. FIG. 2 is a cross-sectional view in the crankshaft direction of a variable compression ratio device in which an eccentric sleeve is incorporated at the large end of the connecting rod and the compression ratio is switched between high and low stages. FIG. 3 is a Y arrow view of the variable compression ratio device of FIG. 2 seen from the Y direction.
4 and 5 are detailed views of the eccentric sleeve locking means surrounded by the broken line IV in FIG. 2, FIG. 4 showing a low compression ratio state, and FIG. 5 showing a high compression ratio state. FIG. 6 shows a hydraulic circuit for supplying hydraulic pressure to the eccentric sleeve locking means.
FIG. 7 is a flowchart for detecting the optimum compression ratio and the optimum ignition timing after detecting the engine operating load state. Figure 8
Is a map for detecting the optimum compression ratio according to the fuel mixture ratio (blade ratio) with the engine load and engine speed as parameters. FIG. 9 is a map for calculating the optimum ignition timing from the output torque and the fuel blend ratio.

First, the overall configuration of the present invention will be described with reference to FIG. Reference numeral 1 is an engine equipped with a variable compression ratio device 2 that switches the compression ratio between two stages, high and low, and switches the compression ratio to two stages, high and low, by supplying hydraulic pressure from a hydraulic circuit 3. The hydraulic circuit 3 is controlled based on the optimum compression ratio calculated by the ECU (electro control unit) 4 with the engine speed, the engine load, and the blend ratio of gasoline and methanol in the fuel as parameters. Further, the ECU 4 calculates the optimum ignition timing from the compression ratio and the engine load after the variable compression ratio device 2 switches the compression ratio, and sends an ignition timing signal to the ignition coil 5. The engine load is the air flow sensor 6,
It is detected in the ECU 4 by the information of the throttle position sensor 7, the water temperature sensor 8, the engine speed sensor 11, and the like. The blend ratio M of gasoline and alcohol in the fuel is measured by the blend ratio sensor 10 provided in the delivery pipe 9 and input to the ECU 4.

Next, the variable compression ratio device 2 will be described with reference to FIGS. 2 and 3. As shown in FIG. 3, the connecting rod 21 has a small end pivotally supported by a piston pin 23 of a piston 22 that reciprocates in the cylinder of the engine, and a large end thereof connected by a crank pin 25 of a crankshaft 24. Is pivoted to. An eccentric sleeve 26 is rotatably provided at the pivotal support portion at the large end of the connecting rod 21 so that the bearing hole of the connecting rod 21 and the crank pin 25 as a support shaft inserted through the bearing hole are eccentric to each other. Has been. That is, the eccentric sleeve 26 is configured such that the center of its inner peripheral circle and the center of its outer peripheral circle are eccentric, and when the outer periphery of the crank pin 25 is rotated 180 degrees from the maximum eccentric position, it takes the minimum eccentric position.

Further, the eccentric sleeve locking means 27 is
A stopper pin 28 is provided as a pin member that moves in the axial direction of the eccentric sleeve 26 (axial direction of the crankshaft 24). By operating this stopper pin 28 with a hydraulic drive mechanism 29 as a piston type fluid pressure mechanism,
Two engaging portions 30, 31 formed on the eccentric sleeve 26
The stopper pin 28 is engaged with the eccentric sleeve 2
The rotation of 6 is fixed at each of the maximum eccentric position and the minimum eccentric position.

Next, the eccentric sleeve locking means 27 will be described with reference to FIGS. 4 and 5. 4 shows a low compression ratio state, and FIG. 5 shows a high compression ratio state. A flange-shaped piston portion 28a is provided at an intermediate portion of the stopper pin 28.
Is integrally provided with an enlarged diameter, and the stopper pin 28 with the piston portion 28a is fitted into the through hole 19 formed in the large end portion of the connecting rod 21. The through hole 19 penetrates the large end of the connecting rod 21 in the axial direction of the crankshaft 24 and is configured as a three-step hole having three diameters. The small diameter hole 19a located at one end is a stopper. The diameter of the pin 28 is substantially the same as that of the medium-diameter hole portion 19b located in the middle portion and is substantially the same as the diameter of the piston portion 28a, and the large-diameter hole portion 19c located at the other end portion is set larger than the piston 28a. .

Therefore, when the stopper pin 28 with the piston portion 28a is inserted into the through hole 19, the stopper pin 28 is liquid-tightly inserted into the small diameter hole portion 19a of the through hole 19 and the medium diameter hole portion of the through hole 19 is inserted. Piston part 2 on 19b
8a is fitted in a liquid-tight manner. Then, a return spring 32 is inserted, and a cap 33 having a through hole 19 having substantially the same shape as the large-diameter portion 19c of the through hole 19 and having the same shape as the stopper pin 28 in the central passage portion is fitted, and the cap 33 is connected to the connecting rod. When the stopper pin 28 is fixed to the through hole 19 of the cap 33, one end of the stopper pin 28 is fitted in the small diameter portion 19a of the through hole 19 in a liquid tight manner, and the other end is fitted in the through hole 19 of the cap 33 in a liquid tight manner. Thus, the medium diameter portion 19b of the through hole 19 is divided into two chambers 34 and 35 by the piston portion 28a. The hydraulic passages 36 and 37 are connected to the chambers 34 and 35, respectively. Accordingly, these two chambers are configured as hydraulic chambers (fluid pressure chambers) 34 and 35 formed on both sides of the piston portion 28a. The return spring 32 is arranged in the hydraulic chamber 34, and urges the stopper pin 28 with the piston portion 28a toward the hydraulic chamber 35. The pressure receiving areas on both sides of the piston portion 28a are set to be equal.

As a result, the stopper pin 28 is moved by moving the piston portion 28a connected to the stopper pin 28 by the piston 28a attached to the stopper pin 28, the hydraulic chambers 34 and 35, the return spring 32, the cap 33, and the like. To drive.

The eccentric sleeve 26 is shown in FIGS.
As shown in FIG. 5, the connecting rod 21 has the flange portions 26a and 26b axially separated from each other so as to sandwich the large end portion thereof, but the eccentric sleeve 26 in one of the flange portions 26a is located at the maximum eccentric position. In part,
A notch-shaped engaging portion 30 is formed, and a position portion (1 with respect to the flange portion 26a where the eccentric sleeve 26 in the other flange portion 26b takes the minimum eccentric position).
At a position rotated by 80 degrees), a notch-shaped engaging portion 31 (FIG. 2) is formed, and the stopper pin 28 moves to the right as shown in FIG. And the eccentric sleeve 26 is fixed to the large end of the connecting rod 21 at the maximum eccentric position. Further, the stopper pin 28 moves to the left as shown in FIGS. 2 and 4, the stopper pin 28 and the engaging portion 31 engage with each other, and the eccentric sleeve 26 is at the minimum eccentric position.
It is fixed to the large end of 1.

When the eccentric sleeve 26 is fixed to the large end of the connecting rod 21 at the maximum eccentric position,
The connecting rod 21 is apparently in the most extended state, and a high compression ratio can be realized. Further, when the eccentric sleeve 26 is fixed to the connecting rod 26 at the minimum eccentric position, the connecting rod is apparently in the most contracted state, and the low compression ratio state can be realized.

Means for applying a desired hydraulic pressure (standard hydraulic pressure) in advance through hydraulic passages 36, 37 and stopper pins 28 with a piston portion 28a are provided in the hydraulic chambers 34, 35 formed on both sides of the piston portion 28a. Means for applying a hydraulic pressure (standard hydraulic pressure + α) higher than the standard hydraulic pressure to the hydraulic chamber 35 in order to move the return spring 32 to the hydraulic chamber 34 side against the urging force is provided. That is, as shown in FIG. 2, the hydraulic passages 36 and 37 pass from the crank journal 38 of the crankshaft 24 through the crank arm 39 portion, and from the crank pin 23 through the large end portion of the connecting rod 21 to the hydraulic chambers 36 and 37, respectively.
37 is connected for communication.

Next, the hydraulic circuit 3 for applying hydraulic pressure to the eccentric sleeve lock means 27 will be described with reference to FIG. A portion of the hydraulic passage 36 outside the crankshaft 24 is connected to the main gallery 40 side, and a portion of the hydraulic passage 37 outside the crankshaft 24 is connected to the sub oil pump 41 or the main gallery 40 side. That is, the lubricating oil from the oil tank or the oil pan 42 is supplied to the main gallery 40 via the oil filter 44 as the lubricating oil of the required hydraulic pressure (the hydraulic pressure that supplies the standard hydraulic pressure) by the oil pump with the relief valve 43. Lubricating oil of standard hydraulic pressure is supplied from the gallery 40 through the hydraulic passage 36. Further, the lubricating oil from the main gallery 40 is supplied to the sub oil pump 41 and discharged as a higher oil pressure (standard oil pressure + α), but the oil pressure from the sub oil pump 41 is switched by the switching valve 45. The hydraulic pressure from the main gallery 40 is selectively supplied to the hydraulic pressure passage 37 via the. That is, when the switching valve 45 is set to the position a, the standard hydraulic pressure from the main gallery 40 is supplied to the hydraulic passage 37, and further, the switching valve 4
When 5 is set to the b position, the high oil pressure (standard oil pressure + α) from the sub oil pump 41 is supplied to the oil pressure passage 37.

Therefore, the switching valve 45 is set to b.
Position of the sub oil pump 4 to the hydraulic passage 37.
The high hydraulic pressure from 1 (standard hydraulic pressure + α) is supplied to the hydraulic chamber 35. At this time, since the standard hydraulic pressure from the main gallery 40 is supplied into the hydraulic chamber 34 via the hydraulic passage 36, the stopper pin 28 with the piston portion 28a is moved to the position shown in FIG. 5 against the urging force of the return spring 15. As shown, the stopper pin 28 is disengaged from the engaging portion 31, and the connecting rod 21, the crankshaft 24, and the eccentric sleeve 26 rotate relative to each other.
The stopper pin 28 and the engaging portion 30 are engaged with each other, and the connecting rod 21 is fixed at the maximum eccentric position of the eccentric sleeve 26, and the high compression ratio state is achieved.

When the switching valve 45 is set to the position "a", the standard hydraulic pressure from the main gallery 40 is supplied to the hydraulic passage 37, and the standard hydraulic pressure is also supplied to the hydraulic chamber 35. At this time, the standard oil pressure is supplied from the main gallery 40 into the oil pressure chamber 34 through the oil pressure passage 36, so that the urging force of the return spring 32 causes the piston 28a to move in the opposite direction to the above. As shown in FIGS. 2 and 4, the attached stopper pin 28 moves leftward to disengage from the engagement portion 30 of the eccentric sleeve 21, engages with the stopper pin 28 and the engagement portion 31, and When the eccentric sleeve 26 is at the minimum eccentric position, the connecting rod 21 is
It is fixed to the large end of the and becomes a low compression ratio state.

Further, the relief valve 45 is (standard hydraulic pressure +
The pressure difference α between α) and the standard hydraulic pressure is adjusted to be constant. Further, when the oil control valve 46 is set to the position a, the pilot oil pressure of the switching valve 45 is lowered and the switching valve 45 can be set to the position a. Further, when the oil control valve 46 is set to the b position, the pilot oil pressure of the switching valve 45 rises and the switching valve 45 can be set to the b position. And this oil control valve 46 is EC
The switching signal from U4 switches the positions to a and b, respectively.

Next, the ECU 40 will be described in detail with reference to FIG. When an ignition key switch (not shown) is turned on, the blend ratio sensor 10 arranged in the delivery pipe 9 detects the mixing ratio (blend ratio) M of methanol to gasoline in the delivery pipe 9.
The blend ratio M is read by the ECU 4 in step S101.

In step S102, the intake air amount A and the engine speed N are read. The intake air amount A is measured by an air flow sensor 6 arranged upstream of the throttle valve in the intake passage, and the engine speed N is detected by an engine speed sensor 11 provided in a drive system or the like. The compression ratio position sensor 12 reads whether the compression ratio of the variable compression ratio device 2 is a high compression ratio or a low compression ratio.

Next, steps S103 to S10
In 8, the high / low of the compression ratio of the variable compression ratio device is determined from the intake air amount A, the engine speed N, and the blend ratio M. In step S103, it is detected from the map shown in FIG. 8 which of the high and low compression ratios is suitable for the current engine load based on the parameters of the intake air amount A, the engine speed N, and the blend ratio M fetched in step S102. To do. For example, when the intake air amount A is a, the engine speed N is n, and the blend ratio M is m, it can be read from the map of FIG. 8 that the engine load is point Q. And M = m in the map
Since the point Q is on the low compression ratio side from the line, it can be seen that the low compression ratio operation is suitable for the current engine load. That is, even with the same engine operating load, the blend ratio M
Depending on the position of the line of M = k (where k is a predetermined value) according to
Different low compression ratios are more suitable.

Next, in step S104, step S10 is performed.
It is determined whether the optimum compression ratio detected in 3 is in the high compression ratio region. In steps S105 and S106, it is read whether the current compression ratio read by the compression ratio position sensor 12 in step S102 is set to high or low. It is determined whether or not the compression ratio state exists.

In step S105, the variable compression ratio device is determined to be in the actual low compression ratio state, and in step S1
When it is determined in 04 that the optimum compression ratio is in the high compression ratio state, in step S107, although the high compression ratio is suitable for the current engine operating load, the variable compression ratio device sets the low compression ratio. Judge that it has become. So E
CU4 sends a signal to switch the compression ratio from low to high,
The oil control valve 46 of the hydraulic circuit 10 is switched to the position of b, and a hydraulic pressure higher than the required hydraulic pressure (standard hydraulic pressure + α) is supplied to the hydraulic passage 37, and the stopper pin 28 moves to the right as shown in FIG. When the eccentric sleeve 26 is engaged with the joint portion 30 and the eccentric sleeve 26 is at the maximum eccentric position, the connecting rod 2
It is fixed at the large end of 1, and the compression ratio switches from low to high.

Similarly, when it is determined in step S106 that the variable compression ratio device is in the actual high compression ratio state, and in step S104 that the optimum compression ratio is in the low compression ratio state, in step S108, Under the current engine operating load condition, the variable compression ratio device determines that the high compression ratio is achieved although the low compression ratio is suitable. Therefore, the ECU 4 issues a signal for switching the compression ratio from high to low, and the oil control valve 4 of the hydraulic circuit 10
6 is switched to the position a, and the required standard hydraulic pressure is supplied to the hydraulic passage 37. As shown in FIGS.
8 moves to the left and engages with the engaging portion 31, the eccentric sleeve 26 is fixed to the large end of the connecting rod 21 at the minimum eccentric position, and the compression ratio switches from high to low.

If it is determined in step S104 that the optimum compression ratio region is the high compression ratio region, and in step S105 that the variable compression ratio device is actually in the high compression ratio state, the optimum compression ratio region is determined to be the optimum compression ratio region. It matches the actual compression ratio,
The ECU 4 does not issue the compression ratio switching signal, and the step S
Go to 109. On the other hand, in step S104, the optimum compression ratio area is determined to be the low compression ratio area, and in step S106,
When it is determined that the variable compression ratio device is actually in the low compression ratio state, the optimum compression ratio and the actual compression ratio match, and the ECU 4 does not issue the compression ratio switching signal and proceeds to step S110. .

Next, in steps S109 to S112, the optimum ignition timing is determined from the compression ratio state of the variable compression ratio device, the blend ratio M, the intake air amount A, and the engine speed N. When it is determined in step S105 that the compression ratio is high, or when the compression ratio is switched to the high compression ratio in step S107, the output torque is changed according to the engine speed N and the intake air amount A read in step S102 in step S109. Calculate Further, in step S111, the optimum ignition timing in the high compression ratio state according to the blend ratio M is determined by a map as shown in FIG. 9, for example, and an ignition timing signal is transmitted to the ignition coil 5 shown in FIG.

Similarly, when it is judged in step S106 that the state is a low compression ratio state, or when the compression ratio is switched to the low compression ratio in step S108, step S110 is followed by step S
The output torque is calculated from the engine speed N and the intake air amount A read at 102. Further step S112
Then, the optimum ignition timing in the low compression ratio state according to the blend ratio M is determined by a map as shown in FIG. 9, for example, and an ignition timing signal is transmitted to the ignition coil 5 shown in FIG.

According to the variable compression ratio device for an internal combustion engine as described above, the blending ratio M of gasoline and methanol detected by the blending ratio sensor 10 is input to the ECU 4.
The optimum compression ratio is detected from the high and low compression ratios in the ECU 4 based on the engine speed N, the intake air amount A, the blend ratio M, and the actual compression ratio P. The optimum compression ratio at this time is the same operating load depending on the blending ratio M of gasoline and methanol, that is, the line of M = k shown in FIG. 8 approaches the high compression ratio side or the low compression ratio side. However, whether the high compression ratio operation or the low compression ratio operation is suitable depends on the value of the blend ratio M. When the actual compression ratio and the optimum compression ratio are different, a switching control signal is transmitted from the ECU 4 to the oil control valve 46, and the switching valve 45 is switched, so that the standard hydraulic pressure is applied to the hydraulic pressure passages 36 and 37. Alternatively, the hydraulic passage 36 is the standard hydraulic pressure, and the hydraulic passage 37 is the (standard hydraulic pressure +
α) is applied, and the stopper pin 2 with the piston portion 28a
8 is moved, the eccentric sleeve 26 is fixed at the maximum / minimum eccentric position, the connecting rod 21 is fixed, and the compression ratio is changed.

For example, when the ECU 4 determines that the optimum compression ratio is in the high compression ratio state, but the actual compression ratio is in the low compression ratio state, the ECU 4 sends the control valve 46 a low compression ratio to a high compression ratio. A switching control signal for switching to is transmitted. As a result, the oil control valve 46 is in the b position, the pilot hydraulic pressure is increased, and the switching valve 45 is in the b position. As a result, the hydraulic passage 37 is supplied with a high hydraulic pressure (standard hydraulic pressure + α) from the sub oil pump 41 to the hydraulic chamber 35, and resists the biasing force of the return spring 15 so that the stopper pin 28 with the piston portion 28a moves to the position shown in FIG. As shown in the drawing, the stopper pin 28 and the engaging portion 30 are engaged with each other in the rightward direction, and the eccentric sleeve 26 is fixed to the connecting rod 21 at the maximum position to be in the high compression ratio state.

On the other hand, when the ECU 4 determines that the optimum compression ratio is in the low compression ratio state but the actual compression ratio is in the high compression ratio state, the ECU 4 sends the control valve 46 to the high compression ratio to the low compression ratio. A switching control signal for switching to is transmitted. As a result, the oil control valve 46 is set to the position a, the pilot hydraulic pressure is reduced, and the switching valve 45 is set to the position a. As a result, the hydraulic passage 37 is supplied with the standard hydraulic pressure from the main gallery 40 to the hydraulic chamber 35, and the stopper pin 28 with the piston portion 28a is moved by the urging force of the return spring 15 as shown in FIG.
Then, as shown in FIG. 4, the stopper pin 28 and the engaging portion 31 are engaged with each other by moving to the right, and the connecting rod 21 is fixed at the minimum position of the eccentric sleeve 26, and the low compression ratio state is achieved.

Further, the optimum ignition timing is determined by the engine operating load, the compression ratio state of the variable compression ratio device, and the blend ratio M of gasoline and methanol. Generally, when the amount of methanol having a high octane number is large, that is, when the blend ratio M is large, the ignition timing limit under the same engine load advances to the advance side. As a result, when a fuel having a large blend ratio M is used, it is possible to perform ignition at an ignition timing at which a larger torque can be obtained.

For example, according to FIG. 9, when M = 0, the variable compression ratio device is set to a high compression ratio state and when the ignition timing is moved to the retard side in order to obtain a high output, knocking occurs, so that a high compression ratio state occurs. The maximum torque at is only T1. However, since knocking does not occur at a low compression ratio, the ignition timing can be advanced relative to the ignition timing at which the maximum torque T2 is obtained, and a larger torque T2 than at a high compression ratio can be obtained. Further, when the blend ratio M becomes a blend ratio larger than M = 0, for example, M = m, the ignition timing limit can be moved to the advance side, so that the maximum torque T3 in the high compression ratio state is It becomes larger than the maximum torque T4. Therefore, it is possible to advance the ignition timing to a position where a torque larger than the maximum torque in the low compression ratio state is obtained in the high compression ratio state, and fuel consumption is improved.

Therefore, in order to avoid knocking in the high compression ratio state, the ignition timing limit must be retarded as compared with the low compression ratio state. However, when the blend ratio M is large, the ignition timing limit is increased. As the vehicle advances to the advance side, the region where the engine can be operated at a high compression ratio without causing knocking is increased compared to when M = 0 (gasoline only). Therefore, even in the operation load region where the engine is operated at a low compression ratio in the past, a region where the maximum torque can be obtained at the high compression ratio operation can be obtained, and the fuel consumption and the maximum torque can be improved. Further, in the operating load region where the high compression ratio operation has been performed conventionally, the region where the engine can be operated without knocking increases, and the maximum torque can be obtained. As a result, not only the optimum compression ratio and the optimum ignition timing according to the blend ratio M of the emulsion fuel during engine operation can be obtained, but also in the emulsion fuel of a fuel with a high octane number such as gasoline + methanol, only the gasoline fuel Compared to when in use, the operating range in the high compression ratio state can be increased, and high output and fuel efficiency can be obtained.

In the present invention, the variable compression ratio device 2 in which the eccentric sleeve 26 is provided at the large end portion of the connecting rod 21 has been described, but the present invention is not limited to this, and the eccentric sleeve is provided at the small end portion. Alternatively, the present invention can be applied to all devices that change the compression ratio, that is, not to switch between high and low stages, but to change the compression ratio by providing a piston or a valve on the top surface of the combustion chamber. Further, in order to detect the engine load state, it is obtained by the intake air amount A by the air flow sensor 6 and the engine speed N by the engine speed sensor 11, but the present invention is not limited to this. Cooling water temperature sensor 8
For example, it may be detected by a sensor that can obtain an engine load.

According to the present invention, the optimum compression ratio is detected based on the blending ratio of the emulsion fuel supplied to the engine and the engine operating load, and the optimum ignition timing suitable for it is set, so that the engine operating load is always maintained. The optimum compression ratio can be obtained, and high output and low fuel consumption can be produced.

[Brief description of drawings]

FIG. 1 is an overall view of a variable compression ratio device for an internal combustion engine according to an embodiment of the present invention.

2 is a crankshaft axial sectional view of a variable compression ratio device in which an eccentric sleeve is incorporated in a large end portion of a connecting rod of the engine 1 shown in FIG. 1 and a compression ratio is switched between high and low stages.

FIG. 3 is a Y arrow view of the variable compression ratio device of FIG. 2 viewed from the Y direction.

FIG. 4 is a detailed view of the eccentric sleeve locking means surrounded by the broken line IV in FIG. 2, showing a low compression ratio state.

5 is a detailed view of the eccentric sleeve locking means surrounded by a broken line IV in FIG. 2, showing a high compression ratio state.

FIG. 6 is a hydraulic circuit for supplying hydraulic pressure to eccentric sleeve locking means.

FIG. 7 is a flowchart for detecting the optimum compression ratio and the optimum ignition timing after detecting the engine operating load state.

FIG. 8 is a map for detecting an optimum compression ratio according to a blending ratio of fuel with engine load and engine speed as parameters.

FIG. 9 is a map for calculating an optimum ignition timing from an output torque and a blend ratio of fuel.

[Explanation of symbols]

 1 Engine 2 Variable Compression Ratio Device 3 Hydraulic Circuit 4 Electronic Computer Unit (ECU) 5 Ignition Coil 6 Air Flow Sensor 7 Throttle Position Sensor 8 Water Temperature Sensor 9 Delivery Pipe 10 Blend Ratio Sensor 11 Engine Speed Sensor 12 Compression Ratio Position Sensor 19 Through Hole 19a Through hole small diameter part 19b Through hole medium diameter part 19c Through hole large diameter part 21 Connecting rod 22 Piston 23 Piston pin 24 Crankshaft 25 Crank pin 26 Eccentric sleeve 27 Eccentric sleeve locking means 28 Stopper pin 28a (Stopper pin) Piston part 29 Hydraulic drive mechanism 30, 31 Engagement part 32 Return spring 33 Cap 34, 35 Chamber (hydraulic chamber) 36, 37 Hydraulic passage 38 Crank jar Le 39 crank arm 40 main gallery 41 sub oil pump 42 oil pan 43 relief valve 44 oil filter 45 switching valve 46 oil control valve

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location F02D 45/00 345 B 7536-3G 364 K 7536-3G 366 F 7536-3G F02P 5/15 B

Claims (1)

[Claims] 1. A variable compression ratio means for varying a compression ratio of an internal combustion engine, an ignition timing switching means for varying an ignition timing of the internal combustion engine, and a plurality of types of fuel mixtures supplied to the internal combustion engine having different physical properties. A blend ratio sensor for detecting a ratio, an operating load state detecting means for detecting an operating load condition of the internal combustion engine, the optimum compression ratio is detected based on the blend ratio and the operating load condition, and a compression ratio switching signal is set as the above. The compression ratio control means for outputting to the variable compression ratio means, the optimum ignition timing of the internal combustion engine is detected based on the operating load state and the compression ratio switching signal, and the ignition timing switching signal is output to the ignition timing switching means. A variable compression ratio device for an internal combustion engine, comprising: