JP2000265867A - Premixed compressed self ignition engine and controlling method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make self ignition timing proper by a simple structure in a premixed compressed self ignition engine sucking fuel and gas containing oxygen for combustion within a cylinder, performing compressed self ignition for premixed gas and burning premixed gas within the cylinder and maintaining rotation of a crankshaft. SOLUTION: A structure in which timing of compressed self ignition in an engine operation cycle can be detected, premixed gas and a ratio of specific heat are different and control gas 21 non-reactive within a cylinder 3 can be supplied within the cylinder 3 is made. Based on timing of detected compressed self ignition, supply amount of control gas 21 to be supplied within the cylinder 3 is controlled and timing of compressed self ignition is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to premixing in which fuel and oxygen-containing gas for combustion are taken into a cylinder, and premixed gas is compressed and ignited in the cylinder to maintain rotation of a crankshaft. The present invention relates to a compression ignition engine and 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, the compression power of the injected fuel is large and the mechanism is complicated, so the overwhelming majority is a spark ignition engine (hereinafter referred to as SI engine). SI
The engine sends air (an example of an oxygen-containing gas for combustion) and a premixed fuel of fuel to a cylinder, compresses the cylinder, and forcibly ignites with a spark plug. By the way, it is known that the efficiency of the engine increases as the compression ratio increases. However, in the case of the SI engine, when the compression ratio is increased, knocking occurs.
Can be suppressed to the extent. 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 more likely to occur when the compression ratio is increased is that the temperature of the unburned portion increases as the compression ratio increases.

[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. 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 sucked into a cylinder, and the premixed gas is compressed and ignited in the cylinder for combustion. The characteristic means of the control method of the homogeneous charge compression ignition engine for maintaining the rotation of the crankshaft is capable of detecting the timing of the compression ignition in an engine operation cycle, as described in claim 1, and A control gas having a specific heat ratio different from that of the premixed gas and not reacting in the cylinder can be supplied to the cylinder, and a control gas supplied to the cylinder is supplied based on the detected timing of the compression ignition. And controlling the timing of the compression auto-ignition.

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.

According to the present invention, a control gas having a specific heat ratio different from that of the premixed gas and not reacting in the cylinder is configured to be supplied to the cylinder. By controlling the amount of control gas supplied to the cylinder, the specific heat ratio of the premixed gas in the cylinder can be changed, and the adiabatic compression temperature can be changed. As a result, the timing of compression ignition can be controlled. Can be. That is, when using a control gas having a specific heat ratio larger than that of the premixed gas, it is possible to increase the temperature after the adiabatic compression with respect to the supply amount of the control gas supplied to the premixed gas to advance the timing of self-ignition. Conversely, if the specific heat ratio is smaller than the premixed gas, the temperature of the control gas supplied to the premixed gas should be reduced by lowering the temperature after adiabatic compression to delay the timing of self-ignition. By controlling the supply amount of the control gas, for example, preferable compression ignition can be realized.

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, a premixed compression ignition engine is constructed in which fuel and oxygen-containing gas for combustion are sucked into a cylinder, and the premixed gas is compressed and ignited and burned in the cylinder to maintain the rotation of the crankshaft. A compression auto-ignition timing detection means for detecting the timing of the compression self-ignition in the engine operation cycle, and a control gas supply amount in the cylinder for supplying a control gas having a specific heat ratio different from that of the premixed gas and not reacting in the cylinder. Control gas supply means for supplying the control gas with the control gas supply means, based on the compression ignition timing detected by the compression ignition timing detection means, and controlling the compression ignition timing. The control means is provided.

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, there is provided a control gas supply means for supplying a control gas having a specific heat ratio different from that of the premixed gas and not reacting in the cylinder with supply amount adjustment in the cylinder. 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, the control gas supply means is actuated to control the pre-charge in the cylinder. The temperature after adiabatic compression is changed by changing the specific heat ratio of the air-fuel mixture. As a result, the timing of compression self-ignition can be changed and controlled, and for example, this can be set to a preferable state. For example, when a control gas having a specific heat ratio smaller than that of the pre-mixed gas and not reacting in the cylinder is used as the control gas, the control means controls the compression ignition to perform in accordance with the information detected by the compression ignition timing detection means. Detect the delay or advance of the actual compression ignition timing with respect to the crankshaft angle timing at which
When there is a delay in the timing of the actual compression ignition, the supply amount of the control gas supplied into the cylinder is controlled to decrease, and when there is an advance in the actual compression ignition timing, It is preferable that the supply amount of the control gas supplied into the cylinder is controlled to increase.

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, by controlling the control means to control the supply amount of the control gas supplied into the cylinder to the increasing side or to control the supply amount of the control gas to the decreasing side, a preferable timing is obtained. be able to.

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. In response to such changes in operating conditions, adjust the control gas supply amount appropriately,
Proposals for obtaining a favorable operating state are as follows.

That is, a premixed compression ignition engine in which fuel and oxygen-containing gas for combustion are sucked into a cylinder, and the premixed gas is compressed and ignited and burned in the cylinder to maintain rotation of a crankshaft. As described in claim 3, the apparatus further comprises operating condition detecting means for detecting operating conditions of the engine, and the control gas having a specific heat ratio different from the premixed gas and not reacting in the cylinder is used as the control gas. Control gas supply means for supplying a supply amount in the cylinder with adjustment of the supply amount, based on the operating condition detected by the operating condition detecting means, the control gas supply means is operated to control the timing of the compression ignition. Control means for performing the operation.

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, as in the example described so far, by providing a control gas supply means for supplying a control gas having a specific heat ratio different from that of the premixed gas and not reacting in the cylinder with supply amount adjustment in the cylinder. The control gas can be supplied into the cylinder. The control means can control the timing of the compression ignition by operating the control gas supply means based on the operating condition detected by the operating condition detecting means. That is, for example, the control means stores in advance information for setting the control gas supply amount or setting the change tendency in accordance with the operation condition or in response to such a change tendency of the operation condition. The control amount of the control gas supplied into the cylinder is controlled according to such reference information obtained in advance. In this way, a favorable operation state can be ensured in accordance with the operating conditions or in response to a change in the operating conditions, together with the adjustment of the control gas supply amount.

Further, as described in claim 4,
The control gas is carbon dioxide gas, nitrogen gas, water vapor,
It is preferable to use argon gas or helium gas. Carbon dioxide gas, nitrogen gas, water vapor, argon gas, or helium gas can be used as the control gas. In engines mainly composed of natural gas, carbon dioxide gas and water vapor can be used as control gases having a lower specific heat ratio than the premixed gas, and argon gas and helium gas can be used as control gases having a higher specific heat ratio than the premixed gas. it can.

It is preferable that the premixed compression ignition engine be provided with a separating device for separating the exhaust gas discharged from the cylinder to obtain a control gas. In this configuration,
A separation device for separating exhaust gas is provided, and it is possible to obtain carbon dioxide gas or water vapor as a control gas having a specific heat ratio different from that of the premixed gas and not reacting in the cylinder. By the control gas supply means, it is possible to control the supply amount of the control gas obtained from the exhaust gas into the cylinder,
The timing of compression ignition can be controlled.

Among these control gases, carbon dioxide contained in the exhaust gas discharged from the cylinder is obtained by subjecting the exhaust gas to a pressure swing method (PSA method) or a heat regeneration method (TS
A) can be obtained by separation using a separation device using method A), and this can be supplied as control gas with control of the supply amount to the cylinder by control gas supply means, and the timing of compression ignition can be controlled. .
Each of the aforementioned exhaust gas separation methods uses an adsorbent,
PSA is a method of separating substances by adsorption and desorption.
In the adsorption process, the specific adsorption component is adsorbed by operating under normal temperature and pressure, and in the desorption process, the specific adsorption component is desorbed by reducing the pressure to atmospheric pressure or lower. In this method, a specific adsorption component is adsorbed by operating at a low temperature, and in the desorption process, the specific adsorption component is desorbed by heating. When the compression ignition engine of the present application is provided with a separation device for separating exhaust gas by using the TSA method and configured to obtain carbon dioxide gas as a control gas, heat energy of the exhaust gas is used as a heat source of the separation device. Alternatively, the exhaust gas generated by the combustion may be supplied as a heat source to the separation device, and the exhaust gas may be separated using the exhaust gas supplied to the separation device.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 The structure of a homogeneous charge compression ignition engine 100 according to the present invention will be described with reference to FIG.
The engine 100 is an engine using natural gas as a fuel, and includes a cylinder 3 having an intake valve 1 and an exhaust valve 2, and an engine body 5 having a piston 4 housed in the cylinder 3. I have. Piston 4 is connecting rod 8
Thus, a rotational output is obtained from the crankshaft 9 according to the reciprocating motion of the piston 4. With this configuration, the premixed gas of natural gas and air is supplied to the intake passage 1
3. The gas is guided into the cylinder 3 via the intake valve 1, passes through the compression / expansion process, and is then exhausted to the exhaust side via the exhaust valve 2 and the exhaust path 14.

One cycle of the 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, the intake valve 1 and the exhaust valve 2 are both closed, the piston 4 moves in a direction to reduce the space in the cylinder 3, and the gas in the cylinder 3 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 in the cylinder 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 application will be described.
In the intake passage 13 of the engine 100 shown in FIG. 1, a control gas supply device 22 capable of supplying carbon dioxide gas to the intake passage 13 as a control gas 21 having a specific heat ratio smaller than that of city gas as fuel is provided. With this configuration,
The control gas 21 can be mixed with the premixed gas supplied into the cylinder 3. 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. The means for detecting the timing of compression ignition in the operation cycle of the engine in this way 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 aforementioned control gas supply device 2
2 will be described.
The control gas 21 is provided with a carbon dioxide gas having a specific heat ratio smaller than that of the premixed gas of city gas as the control gas 21, and is configured to be able to supply the control gas 21 to the intake passage 13 through the flow path 23. The supply amount of the control gas 21 can be set, and based on an output signal of the control device 12,
A predetermined amount of control gas 21 is supplied to the premixed gas.
In this way, the means for setting the amount of the control gas 21 that can be supplied to the premixed gas and supplying the gas to the premixed gas is referred to as control gas supply means B.

As shown in FIG. 2, the control gas 21
As, when the premixed gas is supplied with a carbon dioxide gas having a specific heat ratio smaller than that of the premixed gas and not reacting in the cylinder, the specific heat ratio of the premixed gas decreases in proportion to the supply amount of the carbon dioxide gas, When the supply amount of carbon dioxide gas is increased, the specific heat ratio of the premixed gas changes in a decreasing direction. Therefore, the temperature after adiabatic compression can be changed by adjusting the amount of the control gas 21. That is, as shown in FIG.
When the control gas 21 having a specific heat ratio smaller than that of the premixed gas of the city gas, such as carbon dioxide, is increased, the temperature after the adiabatic compression becomes low, and the timing of the compression self-ignition is delayed. By utilizing this fact, by changing the amount of the control gas 21 supplied to the premixed gas, it is possible to change the timing of the compression self-ignition and to achieve a preferable self-ignition timing.

With the above configuration, the control device 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 supply amount of the control gas 21 to the premixed gas stored in advance, activates the control gas supply means B, and controls the control gas supply device 22 to control the control gas. 21 is supplied to the premixture before compression ignition.

As described above, according to the information detected by the compression ignition timing detection means A, the delay or advance of the actual compression ignition timing is detected, the control gas supply means B is operated, and the pre-compression ignition timing is determined. The means for controlling the amount of the control gas 21 supplied to the air-fuel mixture is referred to as control means C. With this control means C, compression self-ignition is performed in a state where the specific heat ratio of the pre-air-fuel mixture is favorable, and the timing of compression self-ignition is set Appropriate timing can be set.

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 control gas supply means B may be operated based on the input information to control the amount of the control gas 21 supplied to the premixed gas, that is, the specific heat ratio of the premixed gas may be adjusted. It can also control the self-ignition timing. 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 supply amount of the control gas 21 having a specific heat ratio smaller than that of the premixed gas is controlled to the increasing side to lower the cylinder temperature after adiabatic compression, thereby reducing the engine load. Is reduced, the supply amount of the control gas 21 having a specific heat ratio smaller than that of the pre-mixed gas is controlled to a reduced side, so that the temperature in the cylinder after the adiabatic compression can be increased. As a result, the self-ignition engine of the present invention can well cope with the engine load. Further, with respect 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 pre-mixed gas is detected. When the control gas 21 having a specific heat ratio smaller than that of the supplied premixed gas is controlled to increase, and the environmental temperature decreases,
It can be controlled to decrease. 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, means for detecting the operating condition of the engine, such as the load sensor 17 and the environmental temperature sensor 18, is referred to as operating condition detecting means D.

[Embodiment 2] As another embodiment, FIG. 4 shows a case where city gas containing natural gas as a main component is used as a main fuel, an exhaust gas discharged from a cylinder 3 is separated, and carbon dioxide is used as a control gas. 1 shows a configuration of an engine 100 for obtaining gas. In this embodiment, 13A which is city gas is used as a main fuel. By supplying the carbon dioxide gas having a lower specific heat ratio than the city gas to the city gas as the control gas, the timing of the compression ignition can be changed. The engine 100 includes a separation device 30 that separates carbon dioxide from exhaust gas flowing through the exhaust passage 14,
A storage tank 31 for storing the carbon dioxide gas separated by the separation device 30 is provided. The separation device 30 is a device that separates the exhaust gas by the TSA method described above, and uses the heat energy of the exhaust gas as a heat source by flowing the exhaust gas discharged from the cylinder 3 to a heat exchange unit 32 provided in the separation device 30. It is possible. The exhaust gas discharged from the heat exchange section 32 to the exhaust path 15 is further cooled by the cooler 33 and then supplied to the separation device 30, and after extracting carbon dioxide by the TSA method, is discharged to the exhaust path 16.
The carbon dioxide separated from the exhaust gas is the control gas 21
Is temporarily stored in the storage tank 31 via the flow path 17. With these configurations, carbon dioxide gas having a specific heat ratio smaller than that of the premixed gas can be extracted from the exhaust gas, and this carbon dioxide gas is stored as a control gas 21 by the storage tank 31 in the intake passage 13 through the flow path 27. The specific heat ratio of the premixed gas is changed by adjusting the specific heat ratio of the premixed gas by supplying the supply gas with the supply amount adjusted by a flow control valve (not shown) provided in the tank 32, so that the specific heat ratio becomes a suitable self-ignition timing. Can be. The extracted control gas 21 can be supplied to the intake path 13 via the flow path 27 and the control device 1
Based on the output signal from 2, with the adjustment of the supply amount,
The control gas 21 is supplied to the intake path 13. The means for setting the amount of control gas that can be supplied to the premixed gas and supplying the control gas to the premixed gas is referred to as control gas supply means B. With such a configuration, the control means C activates the control gas supply means B in accordance with the information detected by the compression ignition timing detection means A, and controls the control gas 21 to be supplied into the cylinder, as in the above-described embodiment. It is possible to control the supply amount, perform the compression self-ignition in a preferable state after the temperature of the premixed air after the adiabatic compression, and set the timing of the compression self-ignition to an appropriate timing.

Alternative Embodiment (a) As a fuel that can be used for the homogeneous charge 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. (B) In generating the premixed gas, the fuel may be mixed with a gas containing oxygen for combustion of the fuel. For example, it is common to use air 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. (C) In the above-described another embodiment, an example was shown in which city gas was used as the main fuel, and carbon dioxide gas having a small specific heat ratio with the premixed gas of the city gas was used as the control gas. The engine according to the present invention can be configured by using a gas having a specific heat ratio different from the specific heat ratio and not reacting in the cylinder as a control gas. Gas or helium gas, etc.
Water vapor and the like having a specific heat ratio smaller than that of city gas include carbon dioxide gas. (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 supply amount of the control gas is decreased when the environmental humidity increases, and the supply amount of the control gas is increased when the environmental humidity decreases. Regarding the elapsed time from the start, similarly, when using a control gas having a specific heat ratio smaller than that of the premixed gas, if the elapsed time is short, the supply amount of the control gas is relatively reduced and maintained. It is preferable to adjust the supply amount of the control gas in the initial stage to an increase side when a predetermined steady operation time is reached. Similarly, when using a control gas having a specific heat ratio smaller than that of the premixed gas, the supply amount of the control gas is reduced for an increase in the air ratio, and the control gas is reduced for a decrease in the air ratio. Increase the control gas supply. Here, the air ratio is often set in the range of 2 to 6 in the case of the 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 embodiment and another embodiment,
Although the control method has been described in the case of using a control gas having a specific heat ratio smaller than that of the premixed gas as the control gas, when the specific heat ratio is larger than the premixed gas, the control method is the reverse of the case where the specific heat ratio is smaller, that is, If you want to advance the compression ignition timing, increase the control gas supply to increase the temperature after adiabatic compression, and if you want to delay the compression ignition timing, decrease the control gas supply to increase the insulation. The temperature after compression can be reduced. (H) 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. In this case, it is possible to provide the control gas supply means in the fuel flow path, the air flow path, or the cylinder.

[0027]

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.

FIG. 2 is a diagram showing a relationship between a supply amount of carbon dioxide gas as a control gas and a change in a specific heat ratio of a premixed gas.

FIG. 3 is a diagram showing a relationship between a supply amount of carbon dioxide gas as a control gas and a change in compression ignition timing.

FIG. 4 is a diagram showing a configuration of a premixed compression self-ignition engine system of the present application.

[Explanation of symbols]

 Reference Signs List 3 cylinder 9 crankshaft 12 control device 21 control gas 22 control gas supply device 30 separation device 100 compression self-ignition engine A compression self-ignition timing detection means B control gas supply means C control means D operating condition detection means

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02D 45/00 301 F02D 45/00 301M F02M 25/022 F02M 25/07 570D 25/07 570 25/02 T (72) Inventor Shoji Asada 4-1-2, Hirano-cho, Chuo-ku, Osaka City, Osaka Prefecture Inside of Osaka Gas Co., Ltd. (72) Inventor Koji Moriya 4-1-2, Hirano-cho, Chuo-ku, Osaka City, Osaka Osaka Gas Stock In-house (72) Inventor Yuji Nakamura 4-1-2, Hirano-cho, Chuo-ku, Osaka-shi, Osaka F-term in Osaka Gas Co., Ltd. (reference) 3G023 AA18 AB05 AC01 AC07 AC08 AF02 AG03 3G062 AA01 CA00 ED08 ED10 GA05 GA06 GA18 GA21 3G084 AA01 AA02 AA05 BA13 EB08 FA00 FA01 FA02 FA12 FA14 FA18 FA21 FA25 FA26 FA33 FA38 3G092 AA02 AA03 AA05 AA17 AB02 AB05 AB07 AB08 AB09 AB17 AB18 AB20 B A08 DC09 FA16 HA04Z HA05Z HA11Z HA16Z HB05Z HC01Z HC02Z HC03X HC03Z HC05Z HD07X HD07Z HE01Z HE03Z HE08Z

Claims (5)

[Claims] 1. A premixed compression ignition engine that draws fuel and oxygen-containing gas for combustion into a cylinder, compresses and ignites a premixed gas in the cylinder, burns the mixture, and maintains rotation of a crankshaft. The control method of the above, wherein the timing of the compression self-ignition in the engine operation cycle can be detected, and a control gas having a specific heat ratio different from the premixed gas and not reacting in the cylinder can be supplied into the cylinder, A control method for a homogeneous charge compression ignition engine that controls a supply amount of a control gas supplied into the cylinder based on the detected timing of compression ignition and controls the timing of compression ignition. 2. A premixed compression ignition engine that draws fuel and oxygen-containing gas for combustion into a cylinder, compresses and ignites a premixed gas in the cylinder, burns the mixture, and maintains rotation of a crankshaft. A compression ignition timing detecting means for detecting a timing of the compression ignition in an engine operation cycle, and supplying a control gas having a specific heat ratio different from that of the premixed gas and not reacting in the cylinder to the cylinder. Control gas supply means for supplying with control of the amount, based on the timing of compression self-ignition detected by the compression self-ignition timing detection means, actuate the control gas supply means, the timing of the compression self-ignition A homogeneous charge compression ignition engine having control means for controlling. 3. A premixed compression ignition engine that draws fuel and oxygen-containing gas for combustion into a cylinder, compresses and ignites the premixed gas in the cylinder, burns the mixture, and maintains the rotation of the crankshaft. An operation condition detecting means for detecting an operation condition of an engine, and a control for supplying a control gas having a specific heat ratio different from that of the premixed air and not reacting in the cylinder, with a supply amount adjustment in the cylinder. A premixed compression ignition engine having gas supply means, and control means for controlling the timing of the compression self-ignition by operating the control gas supply means based on the operating conditions detected by the operation condition detection means. . 4. The homogeneous charge compression ignition engine according to claim 2, wherein the control gas is carbon dioxide gas, nitrogen gas, water vapor, argon gas, or helium gas. 5. The premixed compression ignition engine according to claim 2, further comprising a separation device that separates exhaust gas discharged from the cylinder to obtain a control gas.