JP2001073774A - Premix compression self-ignition engine and its control - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable to make adequate self-ignition timing, with simple construction, in premix self-ignition engine maintaining rotation of crankshaft taking in fuel and oxygen-containing gas for combustion into burning chamber of cylinder, and making premix air compressed self-ignited and burning. SOLUTION: This control system is provided, on one hand, with compression self-ignition timing detector A to detect the timing of compression self-ignition in engine actuation cycle, and at least temperature control measure B to adjust the temperature of wall face of combustion chamber 6, and control measure C to control timing of compression self-ignition by actuating temperature control B based on the self-ignition timing detected by the detector A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion chamber for a cylinder, in which fuel and oxygen-containing gas for combustion are sucked into a combustion chamber of a cylinder, and the premixed air is compressed and ignited in the combustion chamber for combustion, thereby reducing the rotation of a crankshaft. The present invention relates to a homogeneous charge compression ignition engine to be maintained, and to a technique for maintaining a preferable operating state in such an engine.

[0002]

2. Description of the Related Art Engines, which are internal combustion engines, are roughly classified into a spark ignition engine (Otto cycle engine) and a diesel engine which injects liquid fuel into compressed air. In the case of a conventional diesel engine, since the compression power of the injected fuel is large and the mechanism is complicated, the overwhelming majority is a spark ignition engine (hereinafter referred to as SI engine). S
The I engine sends a premixed gas of air (an example of oxygen-containing gas for combustion) and fuel to a cylinder, compresses the cylinder, and forcibly ignites with a spark plug. It is known that the efficiency of the engine increases as the compression ratio increases. However, in the SI engine, when the compression ratio increases, knocking occurs.
It can be suppressed to about 0. Knocking is a phenomenon in which an unburned portion spontaneously combusts and generates a shock wave before a spark-ignited combustion wave spreads over the entire cylinder, and the establishment of the spontaneous ignition condition is extremely temperature-dependent. . The reason why knocking is likely to occur when the compression ratio is increased is that the temperature of the unburned portion increases with the increase in the compression ratio.

[0003] Recently, the concept of a homogeneous charge compression ignition engine that actively utilizes spontaneous ignition has become a hot topic.
This was originally conceived for the purpose of preventing the particulates of fuel-injected diesel, but rather than injecting the fuel into the compressed air, it mainly uses air and fuel like SI engines. The pre-mixed gas is supplied to the cylinder, spontaneously ignites by compression, and continues to rotate. By applying this method to gas engines, it is possible to avoid knocking problems,
It is possible to increase the compression ratio and obtain high efficiency.

[0004]

One of the major problems in realizing the above-mentioned homogeneous charge compression self-ignition engine is control of the ignition timing. In the SI engine, the ignition timing can be controlled by the spark ignition timing, and in the fuel injection diesel, the ignition timing can be controlled by the fuel injection timing. However, in the case of the homogeneous charge compression self-ignition engine, if the ignition timing is not properly controlled, the ignition timing is not changed. Due to changes in the elapsed time, engine load, air ratio, and the like, the timing at which self-ignition occurs changes, and operation cannot be continued. Accordingly, it is an object of the present invention to provide a technique capable of making the self-ignition timing appropriate in a homogeneous charge compression self-ignition engine.

[0005]

According to the present invention, a fuel and an oxygen-containing gas for combustion are suctioned into a combustion chamber of a cylinder, and a premixed gas is compressed and ignited in the combustion chamber. The characteristic configuration of the control method of the homogeneous charge compression ignition engine for burning and maintaining the rotation of the crankshaft can detect the timing of the compression ignition in the engine operation cycle, as described in claim 1. And controlling the temperature of the wall surface of the combustion chamber based on the detected timing of the compression ignition, thereby controlling the timing of the compression ignition. It is in.

In controlling the operation of the engine, the timing of compression ignition is important. Therefore, first, the actual timing of the compression ignition in the operation cycle of the engine is detected. That is, the engine is used for intake, compression, expansion,
Since the operation is performed through the exhaust stroke, it is detected at which timing self-ignition occurs on a time axis passing through such a stroke. In practice, such self-ignition preferably occurs at the end of the compression stroke or at the beginning of the expansion stroke. Such detection can be performed, for example, by detecting a change in internal pressure or temperature in the cylinder in association with the rotation angle of the crankshaft.

In the present invention, at least the temperature of the wall surface of the combustion chamber is adjustable, and the temperature of the wall surface of the combustion chamber is changed based on the detected timing of compression ignition. By changing the temperature of the premixed gas in the combustion chamber, the compression temperature can be changed, and as a result, the timing of the compression self-ignition can be controlled. That is, when the temperature of the wall of the combustion chamber is increased, the temperature of the premixed gas after compression is increased, and the timing of the self-ignition can be advanced. Conversely, when the temperature of the wall of the combustion chamber is decreased, the compression Later the temperature drops and the timing of self-ignition can be delayed. Thus, by controlling the temperature of the wall surface of the combustion chamber in this way, for example, self-ignition can be performed at a preferable timing. Further, in the present application, at least the temperature of the wall surface of the combustion chamber is changed in order to change the temperature of the premixed gas in the combustion chamber. However, the temperature of the entire cylinder is changed, and as a result, the wall surface of the combustion chamber is changed. May be changed, the temperature of the cylinder head having a large contact area with the combustion chamber after compression may be changed, and at least the temperature of the wall surface of the combustion chamber of the present invention is changed. Of course, such a configuration is also included.

The above description relates to a method for controlling the timing of compression ignition, and such a homogeneous charge compression ignition engine may be configured as follows. preferable. That is, the fuel and the oxygen-containing gas for combustion are sucked into the combustion chamber of the cylinder,
A premixed compression ignition engine for compressively igniting and burning a premixed gas in the combustion chamber to maintain rotation of a crankshaft, wherein a compression ignition timing for detecting a timing of the compression ignition in an engine operation cycle. Along with detecting means, further comprising temperature adjusting means for adjusting at least the temperature of the wall surface of the combustion chamber, based on the timing of compression ignition detected by the compression ignition timing detection means, operating the temperature adjustment means And control means for controlling the timing of the compression self-ignition.

In this homogeneous charge compression ignition engine, the compression ignition timing detecting means detects the compression ignition timing over time in the engine operation cycle. On the other hand, a temperature adjusting means for adjusting at least the temperature of the wall surface of the combustion chamber is provided. Now, the engine of the present application is provided with control means, based on the compression ignition timing detected by the compression ignition timing detection means by this control means, by operating the temperature adjustment means, at least the combustion chamber The temperature of the premixed gas after compression is changed by changing the temperature of the wall surface. result,
The timing of compression ignition can be changed and controlled,
For example, this can be in a favorable state. For example, the control means detects a delay or advance of the actual compression ignition timing with respect to the crankshaft angle timing at which compression ignition should occur, according to the information detected by the compression ignition timing detection means, If there is a delay in the timing of compression self-ignition, the temperature of the wall surface of the combustion chamber is controlled to a high temperature side, and if the actual timing of compression self-ignition is advanced, the temperature of the wall surface of the combustion chamber is reduced. It is preferable to control to the low temperature side.

Generally, in a homogeneous charge compression ignition engine, a preferable timing for compression ignition is specified in relation to the rotation angle of the crankshaft. That is, it is preferable that the compression ignition timing is near the timing at which the piston is at the top dead center. Such an ideal timing is almost unique when the specifications and operating conditions of the engine are specified. Is decided. This is the crankshaft rotation angle timing at which compression ignition should occur. Therefore, it is possible to obtain such information in advance, and to detect the delay or advance of the actual compression ignition timing with respect to this timing by the control means. In this case, it is possible to set a preferable timing by controlling the wall surface of the combustion chamber to a high temperature side or a low temperature side by controlling the control means.

The homogeneous charge compression ignition engine can secure a substantially preferable operating state with the above configuration. The timing of the self ignition can be determined, for example, by the elapsed time from the start of operation of the engine, the engine load, the air ratio, or the environment. In some cases, it is preferable to appropriately set the timing of self-ignition directly in response to changes in operating conditions such as temperature, humidity, and atmospheric pressure, and to maintain a favorable operating state of the engine. In this case, the following configuration can be adopted. The following is a proposal for appropriately adjusting the temperature of the wall surface of the combustion chamber to obtain a preferable operation state in response to such a change in the operation condition.

That is, the fuel and the oxygen-containing gas for combustion are drawn into the combustion chamber of the cylinder, and the premixed gas is compressed and ignited and burned in the combustion chamber to maintain the rotation of the crankshaft. As described in claim 3, the ignition engine is configured to include an operating condition detecting unit that detects an operating condition of the engine, and a temperature adjusting unit that adjusts at least a temperature of a wall surface of the combustion chamber. Control means is provided for controlling the timing of the compression self-ignition by operating the temperature adjusting means based on the operating condition detected by the operating condition detecting means.

In this configuration, the operating condition detecting means detects an operating condition which is considered to affect the self-ignition timing. Such operating conditions are, for example, the elapsed time from the start of operation of the engine, the engine load, the air ratio, the ambient temperature, the humidity, and the atmospheric pressure, as described above.
On the other hand, similarly to the example described so far, a temperature adjusting means for adjusting at least the temperature of the wall surface of the combustion chamber is provided. And the control means can control the timing of the compression ignition by operating the temperature adjusting means based on the operating condition detected by the operating condition detecting means. That is, for example, information for setting the temperature of the wall surface of the combustion chamber or setting the change tendency in accordance with the operation condition or corresponding to the change tendency of the operation condition is stored in the control means in advance. The temperature of the wall of the combustion chamber is controlled in accordance with the standard information obtained in advance. In this way, a favorable operating state can be ensured in accordance with the operating condition or in response to a change in the operating condition, together with the temperature adjustment of the wall surface of the combustion chamber.

Further, such a homogeneous charge compression ignition engine can be configured as follows. That is, as described in claim 4, the temperature adjusting means includes a cooling means for cooling at least a wall surface of the combustion chamber with a cooling liquid, and a cooling capacity adjusting means for adjusting a cooling capacity of the cooling means. is there. In this configuration, a water-cooling type is adopted, and in order to cool the wall surface of the combustion chamber, the cooling liquid is circulated to a space for feeding the cooling liquid such as a water jacket provided inside the cylinder member of the wall surface. The temperature of the wall of the combustion chamber can be adjusted by changing the cooling capacity of the cooling liquid, that is, the ability to cool the wall of the combustion chamber, and the control means adjusts the cooling capacity to control the combustion. The temperature of the wall of the chamber can be changed, the temperature of the premixed gas after compression can be changed, and the compression ignition timing can be controlled,
A favorable operation state can be ensured.

Further, the cooling capacity adjusting means may be a flow rate adjusting means for adjusting the flow rate of the cooling liquid. That is, by changing the flow rate of the cooling liquid by a flow control means such as a flow control valve or a rotary valve, the ability of the cooling liquid to cool the wall surface of the combustion chamber can be changed, and as a result, the temperature of the wall surface of the combustion chamber can be changed. Can be changed. Therefore, by operating the flow rate adjusting means in the control means, as a result, the temperature of the wall surface of the combustion chamber can be changed, and the timing of compression ignition can be controlled.

The cooling capacity adjusting means may be a cooling liquid temperature adjusting means for adjusting the temperature of the cooling liquid. . That is, by changing the temperature of the coolant by the coolant temperature adjusting means, the ability of the coolant to cool the wall surface of the combustion chamber can be changed, and as a result, the temperature of the wall surface of the combustion chamber can be changed. As before, the timing of the compression ignition can be controlled by the control means. Further, both of these cooling capacity adjusting means can be provided. That is, by adjusting the flow rate of the cooling liquid and the temperature of the cooling liquid, the cooling capacity of the cooling means can be significantly changed.

Further, in such a homogeneous charge compression ignition engine, the temperature of the coolant can be adjusted as follows. That is, as described in claim 7, the cooling means is means for circulating the cooling liquid in a radiator portion where the cooling liquid is air-cooled by a fan and in the cylinder, and the cooling capacity adjusting means is provided. Means for adjusting the number of revolutions of the fan to adjust the temperature of the coolant supplied into the cylinder.
By adjusting the rotation speed of the fan provided in the radiator in this way, the amount of heat radiation of the coolant after flowing through the cylinder can be changed, and as a result, the temperature of the coolant supplied to the cylinder can be reduced. Can be changed. Therefore, by controlling the number of revolutions of the fan by the control means, the cooling capacity of the cooling liquid changes, and as a result, the temperature of the wall surface of the combustion chamber is changed, and the temperature of the premixed air after compression is changed. As a result, the compression ignition timing can be controlled, and a favorable operating state of the homogeneous charge compression ignition engine can be ensured with a simple configuration.

[0018] In the premixed compression ignition engine, the cooling liquid is a liquid having a boiling point higher than 100 ° C (101 kPa (1 atm)). Is preferred. As in the present invention,
In order to actively control the temperature of the combustion chamber and control the timing of the premixed compression auto-ignition, when a coolant having a boiling point of 100 ° C. or less is used as a coolant, the coolant boils,
Since it may not be possible to accurately control the temperature of the wall surface of the combustion chamber, as described above, by using a liquid having a boiling point higher than 100 ° C. as the cooling liquid, the cooling liquid can be accurately controlled without boiling. Since the temperature of the wall surface of the combustion chamber can be adjusted in a short time, the timing of compression ignition can be reliably controlled. As such a liquid, a liquid having a boiling point as high as possible is preferable, but a liquid having a boiling point of about 250 ° C. or less is easily available.

Further, in such a homogeneous charge compression ignition engine, the coolant is preferably an engine oil, and mineral oil or the like used for the engine oil is preferably used. Since the boiling point is higher than 100 ° C., as described above, the temperature of the wall of the combustion chamber can be accurately adjusted to control the timing of compression ignition,
A premixed compression ignition engine that performs compression ignition at a preferable timing can be configured.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of a homogeneous charge compression ignition engine 100 according to the present invention will be described with reference to FIG. Engine 10
Numeral 0 denotes an engine using natural gas as a fuel.
Cylinder head 5 equipped with an exhaust valve 2 and a piston 4
Is provided. The piston 4 is connected to the crankshaft 9 by a connecting rod 8, and a rotational output is obtained on the crankshaft 9 as the piston 4 reciprocates. With this configuration, a premixed gas of natural gas and air is guided into the combustion chamber 6 in the cylinder 3 through the intake passage 13 and the intake valve 1, and after undergoing a compression / expansion stroke, is subjected to the exhaust valve 2 and the exhaust passage. The air is exhausted to the exhaust side via the air outlet 14. In addition, the engine 100 supplies water CW (an example of a cooling liquid) into a water jacket 20 provided inside a member of the cylinder 3 so as to take heat of the cylinder 3 by cooling the cylinder 3 and the like with water. A water cooling system 50 that radiates heat in the radiator 23 is provided. That is, the cooling water CW pressure-fed by the water pump 27 is supplied into the water jacket 20 in the cylinder 3 through the supply port 21, removes heat from the cylinder 3 and the cylinder head 5, and is discharged from the discharge port 22.
The discharged cooling water CW is supplied to the bypass flow path 25 or the radiator 23 by the thermostat 2 described later, and the cooling water CW supplied to the radiator discharges internal heat to the atmosphere with the help of the fan 24. , Water jacket 20. Further, when the cooling water CW is at a low temperature, for example, at the time of starting the engine, the thermostat 26 allows the cooling water CW to flow through the bypass passage 25 and does not radiate the heat of the cooling water CW. When the cooling water CW reaches, for example, about 70 ° C., the cooling water CW is circulated through the radiator 23 to radiate heat. Such a cooling system 50 is the same as that provided in a conventional engine. In the present invention, as will be described later, a flow control valve 28 such as a rotary valve for controlling the flow rate of the cooling water CW is used. Have.

One operation cycle of the engine is completed through an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke. Normally, in the intake stroke, only the intake valve 1 is opened, and suction of premixed air is performed. In the compression stroke, both the intake valve 1 and the exhaust valve 2 are closed, and the piston 4 moves in a direction to reduce the space in the combustion chamber 6, and the gas in the combustion chamber 6 is compressed. The position of the piston 4 in a state where the compression is completed is called a top dead center, and the compression ignition in the present application preferably occurs at a timing when the piston 4 is located near this position. The expansion stroke is a stroke in which the piston 4 moves in a direction to increase the space inside the combustion chamber 6 due to the high-pressure gas generated by the combustion. Even during this process, the intake valve 1 and the exhaust valve 2 are both closed. Further, in the exhaust stroke, the exhaust valve 2
Only the open state is set, and the exhaust gas in the cylinder 3 is discharged as the piston 4 moves in the direction to reduce the space in the cylinder 3. The above strokes are the ones that a four-stroke engine normally has. Basically, a homogeneous charge compression ignition engine is no different from other engines except that ignition is caused by heat generated by compression. .

Hereinafter, the characteristic configuration of the present invention will be described.
The water cooling system 50 of the engine 100 shown in FIG. 1 includes a flow control valve 28 for controlling the flow of the cooling water CW. On the other hand, an internal pressure sensor 10 for detecting an internal pressure in the cylinder 3 is provided, and a crank angle sensor 11 for detecting an angle of the crankshaft 9 is provided. The output information from the internal pressure sensor 10 is compared with a preset set value, and the comparison result and the detected crank angle are sent to the control device 12 provided in the engine. Therefore, the control device 12 can obtain information on the state of the internal pressure in the cylinder with respect to the crank angle and the set value at each time point. The timing at which the cylinder internal pressure exceeds the set value is the actual self-ignition timing. As described above, the means for detecting the timing of compression ignition in the operation cycle of the engine includes:
This is referred to as compression ignition timing detection means A. Here, the compression ignition timing detecting means A recognizes the crankshaft angle as information replacing the time axis of the operation cycle, and detects at what timing the crankshaft angle is at which compression ignition occurs. Thus, the timing of self-ignition is specified.

On the other hand, the combustion regulating valve 28 will be described. The opening of the combustion regulating valve 28 is controlled by the control device 12, and by changing the flow rate of the cooling water CW, Changing the temperature of cylinder 3
As a result, the temperature of the wall surface of the combustion chamber 6 can be changed.
The means for adjusting the temperature of the cooling water CW to adjust the temperature of the wall surface of the combustion chamber 6 in this manner is referred to as temperature adjusting means B.

As described above, by adjusting the temperature of the wall surface of the combustion chamber 6 by the temperature adjusting means B, the temperature of the premixed gas in the combustion chamber 6 can be adjusted.
When the flow rate of W is increased, the temperature of the cylinder 3 and the wall surface of the combustion chamber 6 is decreased, and the temperature of the premixed gas in the combustion chamber 6 is decreased. Conversely, when the flow rate of the cooling water CW is decreased, the cylinder 3 and the temperature of the wall surface of the combustion chamber 6 rise, and the temperature of the premixed gas in the combustion chamber 6 rises. Therefore, by adjusting the temperature of the wall surface of the combustion chamber 6 by the temperature adjusting means B, the combustion chamber 6
Can change the temperature of the premixed gas after compression in the
When the temperature of the premixed gas increases, the compression ignition timing becomes earlier, and when the temperature of the premixed gas decreases, the compression ignition timing becomes later. By utilizing this fact, the temperature of the wall surface of the combustion chamber 6 is changed by the temperature adjusting means B, so that the timing of the compression self-ignition can be changed to achieve a preferable self-ignition timing.

With the above-described configuration, the control unit 12 provides the self-ignition timing information (actually, the crank pressure exceeding the set value at each crank angle to the set value at each crank angle) to the control device 12. Corner information) is input. On the other hand, the control device 12 includes a storage unit 120 therein, and according to the operating conditions,
Information on the timing (specific crank angle) at which compression ignition should occur is provided. Such a preferred timing of self-ignition is known empirically when the specification of the engine is fixed, and can be stored in advance.
In the control device 12, the actual self-ignition timing (cylinder angle at which the cylinder internal pressure exceeds the set value) detected by the compression self-ignition timing detection means A during the operation of the engine and the preferable self-ignition timing ( (Preferable cylinder angle). In this way, the delay or advance of the actual self-ignition timing is determined. Based on the result, the control device 12 determines the flow rate of the cooling water CW stored in advance, activates the temperature adjusting means B, and sets the flow rate adjusting valve 28.
Thereby, the flow rate of the cooling water CW is set, and the temperature of the wall surface of the combustion chamber 6 is changed.

As described above, the delay or advance of the actual compression ignition timing is detected in accordance with the information detected by the compression ignition timing detection means A, the temperature adjusting means B is operated, and the temperature of the wall surface of the combustion chamber 6 is detected. Is called control means C, and the control means C controls the combustion chamber 6.
The wall surface has a preferable temperature, and the compression self-ignition is performed in a preferable state of the temperature of the premixed gas after compression, and the timing of the compression self-ignition can be set to an appropriate timing.

Now, in addition to the detection information from the internal pressure sensor 10 and the crank angle sensor 11 as described above, load information on the engine and temperature and humidity information on the environment around the engine are input to the control device 12. The system may be configured as described above. Based on the input information, the temperature adjusting means B is operated to control the flow rate of the cooling water CW, that is, the temperature of the wall surface of the combustion chamber 6 is controlled, and the self-ignition timing Can also be controlled. This configuration will be described below. With respect to the engine load, a configuration is employed in which an engine load detection sensor 17 (an example of means) for monitoring the required number of revolutions of the engine and the like is provided. When the engine load detected by the detecting means 17 increases, the flow rate of the cooling water CW is controlled to increase, the temperature of the wall surface of the combustion chamber 6 is changed to low temperature, and When the temperature is lowered and the engine load decreases, the cooling water C
By controlling the flow rate of W to the decreasing side, the temperature of the wall surface of the combustion chamber 6 can be changed to the higher temperature side, and the temperature of the compressed premixed gas can be increased. As a result, the self-ignition engine of the present invention can well cope with the engine load, and can self-ignite at a preferable timing. Further, with regard to the environmental temperature, a temperature sensor 18 (an example of an environmental temperature detecting means) for detecting the environmental temperature is provided, and when the environmental temperature detected by the environmental temperature detecting means 18 rises, the cooling water CW
Is controlled to increase, the temperature of the wall surface of the combustion chamber 6 is changed to low temperature, and when the environmental temperature decreases, the cooling water C
By controlling the flow rate of W to the decreasing side, the temperature of the wall surface of the combustion chamber 6 can be changed to the higher temperature side. As a result, the timing of self-ignition can be set to a preferable timing even with respect to fluctuations in environmental temperature and the like. Here, the load sensor 17
Means for detecting the operating conditions of the engine, such as the engine and the environmental temperature sensor 18, are referred to as operating condition detecting means D.

[Another Embodiment] (A) In the above embodiment, the water cooling system 5 is used as the temperature adjusting means B for adjusting the temperature of the wall surface of the combustion chamber 6.
Although the configuration in which the flow rate adjusting valve 28 for adjusting the flow rate of the cooling water CW of 0 is provided has been described, it is also possible to adjust the discharge rate of the water pump 27 to adjust the flow rate of the cooling water CW. . In addition to adjusting the flow rate of the cooling water CW to adjust the temperature of the wall surface of the combustion chamber 6, the cooling water CW
It is also possible to adjust the temperature of the wall surface of the combustion chamber 6 by changing the temperature of the cooling water in the radiator 23, as shown in FIG. By changing the heat release amount of the CW, it is possible to change the temperature of the cooling water CW supplied to the water jacket 20 to change the temperature of the wall surface of the combustion chamber 6. , The compression ignition timing is controlled based on the detection result, and the preferable operation state can be maintained. (B) As a fuel that can be used for the premixed compression ignition engine of the present application, city gas or the like is suitable.
Any fuel, such as propane, methanol, hydrogen, etc., can be used. (C) In generating the premixed gas, the fuel may be mixed with a gas containing oxygen for combustion of the fuel. For example, air is generally used as the oxygen-containing gas for combustion. It is. However, as such a gas, it is possible to use, for example, an oxygen-enriched gas having an oxygen component content higher than that of air. (D) In the above-described embodiment, the timing of self-ignition is detected as a timing at which the cylinder internal pressure exceeds a predetermined set value, but such timing detection is based on temperature and vibration. Also, there is a method using a photo sensor for detecting light emission of self-ignition, and further, a knocking sensor is attached to a cylinder,
It may be detected from the signal of this sensor. Further, although the timing in the operation cycle is specified in relation to the crankshaft angle, the timing may be specified on the time axis. (E) In the above-described embodiment, the case where the engine load and the environmental temperature are mainly described as the operating conditions of the engine has been described. However, the operating conditions that affect the self-ignition include the environmental humidity and the atmospheric pressure. , The elapsed time from the start, the air ratio, the supercharging pressure, the fuel gas composition, and the like. Therefore, it is preferable to provide a sensor for detecting these states and perform control according to the output of this sensor. For example, the temperature of the wall surface of the combustion chamber 6 is increased with respect to an increase in the environmental humidity, and the temperature of the wall surface of the combustion chamber 6 is decreased with a decrease in the environmental humidity. When is short, it is preferable to control the temperature of the wall surface of the combustion chamber 6 to be relatively increased, and to control the temperature of the wall surface of the combustion chamber 6 to be reduced with time. Similarly, with respect to the air ratio, the temperature of the wall surface of the combustion chamber 6 is increased when the air ratio is increased, and the temperature of the wall surface of the combustion chamber 6 is decreased when the air ratio is decreased. Here, the air ratio is often set in the range of 2 to 6 in the case of a homogeneous charge compression ignition engine, and corresponds to a change in ascent / descent in this range. (F) In the above embodiment, the description has been given in relation to a so-called four-cycle engine. However, the present application is applicable to a two-cycle engine. (G) In the above-described embodiment, the structure in which the premixed gas that is the premixed gas of the fuel and the oxygen-containing gas for combustion is sucked into the cylinder has been described. The invention of the present application is also applicable to a structure in which the premixed gas is separately supplied, for example, into a cylinder at an initial stage of a compression stroke to form a premixed gas, and the mixture is compressed and self-ignited. (H) In the above embodiment, based on the operating condition of the engine detected by the operating condition detecting means D,
The configuration has been described in which the temperature and the flow rate of the cooling water CW are changed and self-ignition is performed at a preferable timing. However, if the temperature of the cooling water CW corresponding to this operating condition is known in advance, the control means A temperature sensor or the like for detecting the temperature of the cooling water CW, and the temperature of the cooling water CW is determined based on the detected operating conditions and the stored relationship. It can also be configured to set. (I) In the above embodiment and another embodiment, the configuration in which the temperature of the wall surface of the combustion chamber is adjusted by the cooling water CW of water has been described. However, it is also possible to use a liquid higher than 100 ° C. as a cooling liquid, and to adjust the temperature of the wall of the combustion chamber with such a liquid, thereby accurately adjusting the temperature of the wall of the high-temperature combustion chamber. Thus, the timing of compression ignition can be reliably controlled.

[0029]

Thus, the above-mentioned method can realize a homogeneous charge compression ignition engine at a low cost.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a homogeneous charge compression ignition engine system of the present application.

[Explanation of symbols]

 Reference Signs List 3 Cylinder 4 Piston 6 Combustion chamber 9 Crankshaft 12 Controller 50 Water cooling system 100 Premixed compression ignition engine A Compression ignition timing detection means B Temperature adjustment means C Control means D Operating condition detection means CW Cooling water

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3G023 AA02 AA06 AB05 AC01 AC07 AD10 3G092 AA02 AA05 AB08 BA08 DF00 DG07 EA01 EA02 EC09 FA06 FA16 HA11Z HC00X HC01Z HE03Z HE08X

Claims (9)

[Claims] 1. A premixed compressor that inhales fuel and oxygen-containing gas for combustion into a combustion chamber of a cylinder, compresses and ignites a premixed gas in the combustion chamber, and burns the mixture to maintain rotation of a crankshaft. A method for controlling an ignition engine, comprising: a structure capable of detecting a timing of the compression ignition in an engine operation cycle and adjusting at least a temperature of a wall surface of the combustion chamber, based on the detected timing of the compression ignition. And controlling the temperature of the wall surface of the combustion chamber to control the timing of the compression ignition. 2. A premixed compressor that inhales fuel and a combustion oxygen-containing gas into a combustion chamber of a cylinder, compresses and ignites a premixed gas in the combustion chamber, and burns the mixture to maintain rotation of a crankshaft. An ignition engine, comprising: compression ignition timing detection means for detecting a timing of the compression ignition in an engine operation cycle; and temperature adjusting means for adjusting at least a temperature of a wall surface of the combustion chamber; A premixed compression ignition engine having control means for controlling the timing of the compression ignition by operating the temperature adjusting means based on the timing of the compression ignition detected by the timing detection means. 3. A premixed compressor that inhales fuel and an oxygen-containing gas for combustion into a combustion chamber of a cylinder, compresses and ignites a premixed gas in the combustion chamber, and burns the mixture to maintain rotation of a crankshaft. An ignition engine, comprising: operating condition detecting means for detecting an operating condition of the engine; and temperature adjusting means for adjusting at least a temperature of a wall surface of the combustion chamber, wherein the operating condition detected by the operating condition detecting means is A homogeneous charge compression ignition engine having control means for controlling the timing of the compression ignition by operating the temperature adjustment means based on the temperature adjustment means. 4. A cooling means for cooling at least a wall surface of the combustion chamber with a cooling liquid, and a cooling capacity adjusting means for adjusting a cooling capacity of the cooling means. Premixed compression ignition engine. 5. The homogeneous charge compression ignition engine according to claim 4, wherein said cooling capacity adjusting means is a flow rate adjusting means for adjusting a flow rate of said coolant. 6. The homogeneous charge compression ignition engine according to claim 4, wherein the cooling capacity adjusting means is a cooling liquid temperature adjusting means for adjusting a temperature of the cooling liquid. 7. The cooling means is means for circulating the cooling liquid in a radiator portion for cooling the cooling liquid with a fan by air and in the cylinder, and the cooling capacity adjusting means adjusts the rotation speed of the fan. 7. The homogeneous charge compression ignition engine according to claim 6, wherein said means is a means for adjusting the temperature of the cooling liquid supplied into said cylinder. 8. The premixed compression ignition engine according to claim 4, wherein the cooling liquid is a liquid having a boiling point higher than 100 ° C. 9. The homogeneous charge compression ignition engine according to claim 8, wherein the coolant is engine oil.