JP2001271670A - Multi-cylinder pre-mixed compression self-ignition engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make self-ignition timing in all combustion chambers proper and provide a stable operation state in a multi-cylinder pre-mixed compression self-ignition engine 100 provided with a plurality of cylinders 3 which form combustion chambers 5 on the inside together with inserted pistons 4, compressing air-fuel mixture of a fuel and a gas, containing oxygen in each combustion chamber 5 and burning air-fuel mixture by making air-fuel mixture self-ignite. SOLUTION: This engine is provided with each of air-fuel mixture temperature adjusting means 23 for adjusting each temperature of air-fuel mixture, before compression in each combustion chamber 5, each self-ignition timing detection means 10 for detecting each of self-ignition timing in each combustion chamber 5 and a control means 12 for making each of the air-fuel mixture temperature adjusting means 23 work, based on a detection result of each self- ignition timing detection means 10 and controlling each self-ignition timing in each combustion chamber 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a plurality of cylinders having a combustion chamber formed therein together with an inserted piston, and compresses a mixture of fuel and oxygen-containing gas in each combustion chamber to cause self-ignition. The present invention relates to a multi-cylinder premixed compression ignition engine to be burned, and to a technique for maintaining a preferable operating state in such an engine.

[0002]

2. Description of the Related Art Recently, the concept of a homogeneous charge compression ignition engine that actively utilizes natural ignition has been attracting attention. This kind of homogeneous charge compression ignition engine has been developed for the purpose of preventing the particulates of a diesel engine, and has just begun research and development. The homogeneous charge compression self-ignition engine performs self-ignition using adiabatic compression similarly to the diesel engine.However, instead of injecting fuel into the compressed air in the combustion chamber to cause self-ignition, mainly a spark ignition engine is used. As in an ignition engine, a mixture of fuel and air (an example of an oxygen-containing gas) is formed in a combustion chamber, and the mixture is compressed by a piston in the combustion chamber to raise the temperature to the ignition point of the fuel and self-ignite. To burn the fuel. If this technique is applied to a gas engine, it is possible to increase the compression ratio and to cause the ultra-lean air-fuel mixture to self-ignite and burn, thereby achieving high efficiency and low NOx operation.

[0003]

One of the major problems in realizing the above-mentioned homogeneous charge compression 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, the ignition is started as it is (if the self-ignition timing is not properly controlled). Due to changes in the elapsed time from the start, the engine load, the air ratio, etc., the timing at which self-ignition occurs changes and the operation cannot be continued. In particular, when the homogeneous charge compression ignition engine is configured as a multi-cylinder homogeneous charge compression ignition engine having a plurality of cylinders that form a combustion chamber together with an inserted piston, the operating environment in each cylinder is the same. Otherwise, the operating conditions (self-ignition timing) differ between the cylinders. Also, in the case of a multi-cylinder engine, the supply air is distributed by an air supply manifold or the like and supplied to the combustion chambers. The temperature of the supply air supplied to the combustion chambers is different, and as a result, it is difficult to cause the compression ignition in each of the combustion chambers in the same state.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a multi-cylinder premixed compression ignition engine capable of optimizing the self-ignition timing in all combustion chambers and obtaining a stable operation state in view of the above circumstances. It is to realize.

[0005]

According to a first aspect of the present invention, there is provided a multi-cylinder premix compression self-ignition engine according to the present invention. A fuel-air mixture temperature adjusting means for individually adjusting the temperature; a self-ignition timing detecting means for individually detecting the self-ignition timing in each of the combustion chambers; and a detection by the respective self-ignition timing detecting means. On the basis of the result, a control means for operating the respective air-fuel mixture temperature adjusting means and individually controlling the self-ignition timing in each of the combustion chambers is provided.

[Effects] As in the present configuration, the actual timing of the compression ignition in the operation cycle of the engine is individually detected in each combustion chamber by the self-ignition timing detection means. That is, since the engine operates through the air supply, compression, expansion, and exhaust strokes, it detects at which timing self-ignition occurs on the time axis passing through such strokes. In practice, such self-ignition preferably occurs at the end of the compression stroke or at the beginning of the expansion stroke. Such detection of the actual self-ignition timing may be configured, for example, to detect a change in the internal pressure of each combustion chamber in association with the rotation angle of the crankshaft, or to detect the operating state of each cylinder (for example, The temperature of the cylinders, the temperature of the cooling water flowing through each cylinder, the temperature of the exhaust gas discharged from each combustion chamber, the state of occurrence of knocking in each cylinder, etc.). This can be achieved by estimating the actual self-ignition timing based on the relationship between the self-ignition timings.

Further, the temperature of the air-fuel mixture before compression in each combustion chamber can be individually adjusted by the air-fuel mixture temperature adjusting means. Since the timing until the gas is compressed and reaches the ignition point, that is, the timing of so-called self-ignition, changes, as a result, by the mixture temperature control means,
The compression ignition timing in each combustion chamber can be individually adjusted.

Therefore, the control means activates the air-fuel mixture temperature adjusting means based on the actual compression ignition timing in each combustion chamber detected by the self-ignition timing detecting means, for example, for the actual self-ignition. In a cylinder whose timing is later than the preferable timing, the temperature of the air-fuel mixture before compression is increased, and in a cylinder whose actual self-ignition timing is earlier than the preferable timing, the temperature of the air-fuel mixture before compression is lowered. In addition, the temperature of the air-fuel mixture formed in each combustion chamber can be individually controlled, and control can be performed such that self-ignition at a preferable timing occurs in all combustion chambers. Therefore, it is possible to realize a multi-cylinder premixed compression ignition engine that can make the timing of the self ignition in all the combustion chambers preferable.

[Structure 2] According to a second aspect of the present invention, in addition to the structure of the multi-cylinder type premixed compression self-ignition engine according to the first aspect, the multi-cylinder premixed compression self-ignition engine according to the present invention further comprises: EGR means for supplying an exhaust gas after combustion of the air-fuel mixture to the respective combustion chambers,
E separately adjusting the amount of exhaust gas supplied to each of the combustion chambers and individually adjusting the temperature of the air-fuel mixture before the compression.
And a GR amount adjusting means.

[Effects] As in the present configuration, EGR means and EGR amount adjusting means are provided as air-fuel mixture temperature adjusting means, and a part of exhaust gas is supplied to the combustion chamber before compression self-ignition with adjustment of the supply amount. However, in a cylinder whose actual self-ignition timing is later than the preferable timing, the amount of exhaust gas supplied to the air-fuel mixture before compression is increased, and in a cylinder whose actual self-ignition timing is earlier than the preferable timing, the mixing before compression is increased. Such as reducing the amount of exhaust gas supplied to the air, individually adjusting the amount of exhaust gas supplied to each combustion chamber, individually controlling the temperature of the mixture formed in each combustion chamber, In all the combustion chambers, control can be performed so that self-ignition at a preferable timing occurs.

Further, as the EGR means and the EGR amount adjusting means, each cylinder is provided with an EGR flow path connecting an air supply port and an exhaust port, and an EGR amount adjustment means for adjusting an opening degree of the EGR flow path. Exhaust gas is supplied from the exhaust port to the air supply port via the EGR flow path by utilizing the fact that the pressure of the air supply port is lower than that of the exhaust port, and the supply amount is adjusted by the respective EGR amount adjustment valves. Can be adjusted. Therefore, it is possible to realize a multi-cylinder premixed compression ignition engine with a simple configuration that can make the timing of self-ignition in all the combustion chambers desirable.

Also, without providing such an EGR flow path, by adjusting the opening / closing timing of an intake valve or an exhaust valve in each cylinder individually, it is possible to supply the air-fuel mixture before compression in each combustion chamber. The amount of exhaust gas to be discharged can be adjusted. Specifically, the EGR means and the EG
As the R amount adjusting means, by temporarily opening the air supply valve provided in the combustion chamber during the exhaust stroke, exhaust gas flows into the air supply port during the exhaust stroke, and in the next air supply stroke, The supply air containing the exhaust gas can be supplied to the combustion chamber, and by adjusting the time in which the exhaust gas is temporarily opened in each cylinder, the exhaust gas flowing into each air supply port during the exhaust stroke can be reduced. The amount can be adjusted, and the amount of exhaust gas supplied to each combustion chamber in the next air supply stroke can be adjusted.

Further, as the EGR means and the EGR amount adjusting means, an exhaust valve provided in the combustion chamber is temporarily opened during an air supply stroke, so that exhaust gas from an exhaust port is discharged during the air supply stroke. By adjusting the time to open temporarily in each cylinder,
The amount of exhaust gas supplied to each combustion chamber during the air supply stroke can be adjusted. Further, as the EGR means and the EGR amount adjusting means, the exhaust valve closes the exhaust valve before the BDC (bottom dead center) in the exhaust stroke, so that the exhaust gas of the combustion chamber is completely exhausted to the exhaust port side in the exhaust stroke. Since the exhaust gas cannot be discharged, a part of the exhaust gas can be left in the next air supply stroke, and the amount of the exhaust gas remaining in each combustion chamber is adjusted by adjusting the timing of closing the exhaust valve in each cylinder. be able to.

[Structure 3] A multi-cylinder premixed compression ignition engine according to the present invention, in addition to the structure of the multi-cylinder premix compression self-ignition engine of Structure 1, as described in claim 3, An after-mixture temperature adjusting means is provided in each of the air supply ports for separately introducing fresh air into each of the combustion chambers, and after-cooling each of the fresh air in each of the air supply ports with cooling amount adjustment. It is a cooler.

[Effects] As in the present configuration, each air supply port is provided with an aftercooler, and at least one of the flow rate and the temperature of the cooling water supplied to the aftercooler is adjusted to adjust the air-fuel mixture by the aftercooler. Alternatively, by adjusting the cooling amount of the fresh air of the air (oxygen-containing gas), it is possible to adjust the temperature of the supply air supplied to each combustion chamber and adjust the temperature of each air-fuel mixture before compression. it can. Therefore, it is possible to realize a multi-cylinder premixed compression ignition engine with a simple configuration that can make the timing of self-ignition in all the combustion chambers desirable.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of a homogeneous charge compression ignition engine 100 of the present application will be described with reference to the drawings. Engine 10
Numeral 0 denotes a multi-cylinder engine provided with four cylinders 3 each having therein a combustion chamber 5 together with a piston 4 inserted therein. The respective pistons 4a, 4b, 4c, 4d are connected to one crankshaft 9 by connecting rods 8a, 8b, 8c, 8d, and a rotational output is obtained on the crankshaft 9 according to the reciprocating motion of each piston 4. Can be With this configuration, the air-fuel mixture is supplied to the air supply ports 13a, 13b, and 13 connected to the respective combustion chambers 5 in the air supply manifold 13.
c, 13d and the air supply valves 1a, 1b, 1c, 1d,
Guided to the respective combustion chambers 5a, 5b, 5c, 5d,
After the expansion stroke, the air is exhausted to the exhaust manifold 14 via the exhaust valves 2a, 2b, 2c, 2d and the exhaust ports 14a, 14b, 14c, 14d.

One operation cycle of the engine is completed through an air supply stroke, a compression stroke, an expansion stroke, and an exhaust stroke. Normally, in the air supply stroke, only the air supply valve 1 is opened to suction the premixed air. In the compression stroke, the supply valve 1 and the exhaust valve 2 are both closed, the piston 4 moves in a direction to decrease the combustion chamber 5, and the gas in the combustion chamber 5 is compressed. The position of the piston 4 in a state where the compression is completed is called TDC (top dead center), and the compression ignition in the present application preferably occurs at a timing when the piston 4 is located near the TDC. The expansion stroke is a stroke in which the piston 4 moves in a direction to increase the space in the cylinder 3 by high-pressure gas generated by combustion. The position of the piston 4 in a state where the increase is completed is called a bottom dead center. Even during this stroke, the air supply valve 1 and the exhaust valve 2 are both closed. Further, in the exhaust stroke, the exhaust valve 2 is normally opened and the piston 4
The exhaust gas in the cylinder 3 is discharged with the movement of the combustion chamber 5 in the direction of decreasing the combustion chamber 5. The above process is a process that a four-stroke engine normally has, and basically, the homogeneous charge compression self-ignition engine is different from other engines except that self-ignition is caused by heat generated by compression. Absent.

However, in such a multi-cylinder homogeneous charge compression ignition engine 100, the timing of self-ignition in the combustion chamber 5 changes due to a change in temperature of the air-fuel mixture before compression. In the multi-cylinder premixed compression ignition engine 100 as described above, the air-fuel mixture is distributed by the air supply manifold 13 and the combustion chambers 5a, 5b, 5c, and 5d are separated.
, The flow path until the mixture is supplied is different in each of the combustion chambers 5a, 5b, 5c, 5d. For example, the temperature of the supplied air-fuel mixture is low in the combustion chamber 5a having the short circulation path, and the temperature of the air-fuel mixture supplied is high in the short combustion chamber 5d having the long circulation path, As a result, it was difficult to cause compression ignition in each of the same conditions. Therefore, in the multi-cylinder premixed compression ignition engine 100 according to the present invention, the timing of the self ignition in all the combustion chambers 5a, 5b, 5c, 5d can be made desirable.
The characteristic configuration will be described below.

The engine 100 shown in FIG. 1 has an internal pressure sensor 10 for detecting the internal pressure of each combustion chamber 5 individually.
a, 10b, 10c, 10d, and a crank angle sensor 1 for detecting the angle of the crankshaft 9.
1 is provided. The output information from the internal pressure sensor 10 is compared with a preset value, and the comparison result is as follows:
The detected crank angle is 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 of each combustion chamber 5 with respect to the crank angle and the set value at each time point. The timing at which the internal pressure of each combustion chamber 5 exceeds the set value is the actual compression ignition timing.
The means for individually detecting the timing of compression ignition in the operation cycle of the engine in each combustion chamber 5 is referred to as compression ignition timing detection means. Here, the compression ignition timing detection means recognizes the angle of the crankshaft 9 as information replacing the time axis of the operation cycle, and detects at what timing the compression ignition occurs at the crankshaft 9. Then, the timing of compression self-ignition is specified.

The engine 100 has respective air supply ports 13a, 13b, 13c, 13d and an exhaust port 1
4a, 14b, 14c, and 14d are connected, and EGR amount adjustment valves 20a, 20b, 20c, and 20d capable of adjusting a flow path opening degree.
EGR flow path 21 having (an example of EGR amount adjusting means)
a, 21b, 21c, 21d (an example of EGR means) are provided to supply the exhaust gas from the exhaust port 14 with a high internal pressure to the air supply port 13 with a low internal pressure, and to adjust the supply amount. As a result, the air-fuel mixture in which a part of the high-temperature exhaust gas is mixed is supplied to each combustion chamber 5, and the temperature of the air-fuel mixture before compression in each combustion chamber 5 can be individually adjusted. Means can be configured.

With the above configuration, the control device 12 provides the timing information of the actual compression auto-ignition of each combustion chamber 5 in one operation cycle of the engine 100 (actually, the combustion chamber pressure reaches the set value at each crank angle). On the other hand, crank angle information exceeding this is input separately. on the other hand,
The control device 12 includes a storage unit 120 therein, and includes information on a timing (a specific crank angle) at which compression ignition should occur in accordance with an operating condition. Such a preferred timing of compression ignition is known empirically when the specification of the engine is fixed, and can be stored in advance. Then, in the control device 12, during the operation of the engine, the actual compression ignition timing detected by the compression ignition timing detection means (cylinder angle at which the pressure in the combustion chamber exceeds the set value);
A comparison with the preferred compression ignition timing (preferable cylinder angle) will be made. In this way, it is determined whether the timing of the actual compression ignition is delayed or advanced.

Based on the result, the control device 12 controls the respective EGR amount adjusting valves 20 for the delay or advance of the compression ignition timing stored in advance.
Is determined, the respective EGR amount adjusting valves 20 are individually controlled, the amount of exhaust gas supplied to the air-fuel mixture before compression in each combustion chamber 5 is controlled, and the temperature of the air-fuel mixture is controlled. As described above, according to the information detected by the compression ignition detection means, the delay or advance of the actual compression ignition timing is detected, and the temperature of the air-fuel mixture in each combustion chamber 5 before compression is individually controlled. Is called control means. By this control means, a predetermined amount of exhaust gas is supplied to each of the combustion chambers 5 before compression ignition, and the temperature of compression ignition in a preferable state is reached, so that the timing of compression ignition in all combustion chambers 5 is adjusted. Appropriate timing can be set.

[Other Embodiments] A multi-cylinder homogeneous charge compression ignition engine according to the present invention will be described below with reference to another embodiment different from the above-described embodiment.

<1> In the above embodiment, the EGR means and the EGR amount adjusting means as the air-fuel mixture temperature adjusting means are constituted by the EGR flow path 21 and the EGR amount adjusting valve 20, but will be described separately below. It can also be configured as follows. That is, as shown in FIG.
a, 1b, 1c, 1d and exhaust valves 2a, 2b, 2c, 2
An opening / closing timing setting mechanism 19a, 19b, 19c, 19d for opening and closing d at an arbitrary timing is provided. The opening / closing timing setting mechanism 19 is controlled by the control device 12, and has a time during which the air supply valve 1 is temporarily opened during the exhaust stroke as an EGR means, and supplies the air via the air supply valve 1 during the exhaust stroke. Air ports 13a, 13b, 13
Part of the exhaust gas is discharged to c and 13d, and the exhaust gas is supplied to the combustion chamber 5 in the next air supply stroke. Further, by individually controlling the time during which each air supply valve 1 is temporarily opened in the exhaust stroke, E
As the GR amount adjusting means, the amount of exhaust gas supplied to each combustion chamber can be adjusted, and the temperature of the air-fuel mixture before compression can be individually adjusted in each combustion chamber 5.

Also, separately, the EGR means has a time during which the exhaust valve 2 is temporarily opened during the air supply stroke,
Part of the exhaust gas together with the air-fuel mixture is supplied to the combustion chamber 5 during the air supply process.
It can also be configured to supply air. In this case, the EGR amount adjusting means adjusts the amount of exhaust gas supplied to each combustion chamber by adjusting the time during which the exhaust valve 2 is temporarily opened during the air supply stroke. In the combustion chamber 5, the temperature of the air-fuel mixture before compression can be individually adjusted.

Further, as an EGR means, in a later stage of the exhaust stroke, the exhaust valve 2 is closed before BDC,
A part of the exhaust gas may be left in the combustion chamber 5 and the exhaust gas may be supplied to the air-fuel mixture supplied to the next supply stroke.
Further, by adjusting the timing of closing the exhaust valve, the amount of exhaust gas supplied to the air-fuel mixture can be adjusted.

<2> In the above-described embodiment, the configuration in which the EGR means and the EGR amount adjusting means for supplying the exhaust gas with adjusting the supply amount to the air-fuel mixture and the EGR amount adjusting means as the air-fuel mixture temperature adjusting means has been described. As shown in FIG. 3, each air supply port 13a, 13b, 13c, 13d is provided with an aftercooler 22a, 22b, 22c, 22d, and a flow rate adjustment for adjusting the flow rate of the cooling water flowing in the aftercooler 22. Each of the combustion chambers 5a, 5b, 5c, 5d is provided with a respective one of the valves 23a, 23b, 23c, 23d, and by controlling each of the flow regulating valves 23 individually by the control means.
The temperature of the air-fuel mixture supplied to the can be adjusted separately

<3> As a fuel that can be used in the multi-cylinder premixed compression ignition engine of the present invention, city gas or the like is suitable, but any fuel such as gasoline, propane, methanol, and hydrogen can be used. Can be.

<4> In order to generate the air-fuel mixture supplied to the combustion chamber, the fuel may be mixed with a gas containing oxygen for combustion of the fuel. It is common to use air as the. However, such gases include, for example,
It is possible to use an oxygen-enriched gas or the like having an oxygen content higher than that of air.

<5> In the above embodiment, the timing of the compression ignition was detected as a timing at which the pressure in the combustion chamber exceeds a predetermined set value.
There is also a method using a photo sensor for detecting light emission of self-ignition. Further, a knocking sensor may be attached to a cylinder, and detection may be performed based on a signal from this sensor. Furthermore, although the timing in the operation cycle is specified in relation to the crankshaft angle, the timing may be specified on the time axis.

<6> In the above embodiment,
As the self-ignition timing detection means, a configuration in which the occurrence of self-ignition is directly detected by a pressure sensor has been described, but separately, the temperature of each cylinder, the temperature of cooling water flowing through each cylinder, and the discharge from each combustion chamber The actual self-ignition timing can also be estimated by detecting the temperature of the exhaust gas to be emitted by a temperature sensor or the like. That is, in the combustion chambers in which the respective temperatures are low, it is considered that the air-fuel mixture cannot be sufficiently self-ignited, and the amount of exhaust gas supplied to the combustion chamber is increased to increase the amount of the air-fuel mixture before compression. Increase the temperature and accelerate the timing of self-ignition. Also, although each temperature is high enough,
In a combustion chamber where knocking has been confirmed to occur by a knocking sensor or the like, the timing of self-ignition is considered to be too early, and the amount of exhaust gas supplied to the combustion chamber is reduced to lower the temperature of the air-fuel mixture before compression. , Delay the timing of self-ignition. With this configuration, the air-fuel mixture can self-ignite and burn at a preferable timing in all the combustion chambers.

<7> In the above embodiment,
Although described in connection with a so-called four-stroke engine, the present application is also applicable to a two-stroke engine.

<8> In the above embodiment,
Although the structure in which the mixture of the fuel and the oxygen-containing gas for combustion is formed in advance and supplied to the combustion chamber is shown, the fuel and the combustion oxygen-containing gas are separately supplied to the combustion chamber, for example, in the initial stage of the compression stroke. The invention of the present application can also be applied to a structure in which a mixture is formed by supplying fuel, and the mixture is compressed and self-ignited.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an embodiment of a multi-cylinder premixed compression ignition engine of the present invention.

FIG. 2 is a schematic view showing another embodiment of a multi-cylinder premixed compression ignition engine of the present invention.

FIG. 3 is a schematic view showing another embodiment of a multi-cylinder premixed compression ignition engine of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Supply valve 2 Exhaust valve 3 Cylinder 9 Crankshaft 12 Control device 13 Supply manifold 14 Exhaust manifold 100 Multi-cylinder premixed compression ignition engine

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02D 43/00 301 F02D 43/00 301N 301P F02M 25/07 570 F02M 25/07 570M 570J (72) Inventor Takahiro Sako 4-1-2, Hirano-cho, Chuo-ku, Osaka-shi, Osaka Inside Osaka Gas Co., Ltd. (72) Inventor Shoji Asada 4-1-2, Hirano-cho, Chuo-ku, Osaka-shi, Osaka inside Osaka Gas Co., Ltd. (72) Inventor Shunsaku Nakai 4-1-2, Hirano-cho, Chuo-ku, Osaka City, Osaka Prefecture F-term in Osaka Gas Co., Ltd. (reference) DA11 DA23 EA11 EB02 EB06 EB12 EC03 FA02 FA19 FA21 FA37 FA38 3G092 AA05 AA11 AA17 AB01 AB02 AB05 AB06 AB07 AB20 BA09 DA 02 DA08 DA12 DC09 DE15S DF01 EA01 EA02 EA29 EC01 EC09 FA05 FA06 FA15 FB04 GA08 HA04X HA13Z HC01X HD07X HE04Z

Claims (3)

[Claims] 1. A multi-cylinder type engine comprising a plurality of cylinders which form a combustion chamber together with an inserted piston, wherein a mixture of fuel and an oxygen-containing gas is compressed in each combustion chamber, self-ignited and burned. A mixed compression self-ignition engine, each of which comprises a mixture temperature control means for individually adjusting a temperature of the mixture before compression in each of the combustion chambers, and adjusting a timing of the self-ignition in each of the combustion chambers. Self-ignition timing detecting means for individually detecting each, based on the detection results of the respective self-ignition timing detecting means, actuate the respective air-fuel mixture temperature adjusting means, and adjust the self-ignition timing in each of the combustion chambers. A multi-cylinder homogeneous charge compression ignition engine having control means for controlling separately. 2. The EGR system according to claim 1, wherein said mixture temperature control means supplies exhaust gas after combustion of said mixture to said respective combustion chambers.
2. An EGR amount adjusting means for individually adjusting the amount of exhaust gas supplied to each of the combustion chambers and adjusting the temperature of the air-fuel mixture before compression individually. Multi-cylinder premixed compression ignition engine. 3. The air-fuel mixture temperature adjusting means is provided in each of the air supply ports for introducing fresh air into each of the combustion chambers separately, and adjusts the fresh air in each of the air supply ports with a cooling amount adjustment. 2. The multi-cylinder homogeneous charge compression ignition engine according to claim 1, wherein the engine is an aftercooler that individually cools the engine.