JP2001073775A - Compression ignition type internal combustion engine - Google Patents

Abstract

(57) [Problem] To provide an in-cylinder air-fuel mixture with a high fuel efficiency improving effect while avoiding a knocking phenomenon, thereby increasing combustion efficiency and reducing fuel efficiency and emission. When an engine load detected by a load sensor is equal to or less than a predetermined determination value, a load determination unit instructs an auxiliary energy application control unit to apply auxiliary energy to the air-fuel mixture. At this time, the pressure control unit 32 controls the supercharger 13 such that the in-cylinder pressure near the compression top dead center is about 4 MPa and the in-cylinder temperature is about 730 K, and the temperature control unit 33 is Control.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compression ignition type internal combustion engine, and more particularly to a compression ignition type internal combustion engine which applies auxiliary energy to a mixture in a combustion chamber to promote compression self-ignition.

[0002]

2. Description of the Related Art In a compression ignition type internal combustion engine, ignitability,
In an operating region where there is a problem in flammability, a technique using an auxiliary ignition source such as a heating element is known. For example, Japanese Patent Laying-Open No. 1-301944 discloses a technique in which a diesel engine using alcohol fuel is provided with a spark plug as an auxiliary ignition source.

[0003] According to this prior art, the auxiliary ignition source is turned on when the diesel engine is running at a low speed, low load, and high load, and is turned off when the diesel engine is at a medium load. By correcting the fuel injection amount supplied to the engine, the combustion speed is increased by igniting from an auxiliary ignition source in an operation region where there is a problem in flammability, and the fuel efficiency and emission performance at low rotation and low load are improved. Improvement of output and emission performance at high load,
And reduction of noise can be achieved at the same time.

[0004]

However, in the compression ignition combustion, when a low cetane number fuel such as gasoline is used, the ignitability of the fuel itself is poor. A large amount of unburned fuel remains not only at a low load but also at a medium load, which causes a problem that fuel efficiency is deteriorated and HC in exhaust gas is increased. Further, when the auxiliary energy is applied at a high load, there is a problem that the combustion speed becomes too high and a knocking phenomenon occurs.

[0005] Here, FIG.
The relationship between the air-fuel ratio for the required load and the knocking limit when the FF is performed is shown. By providing auxiliary energy, combustion efficiency can be increased and unburned fuel can be reduced,
The air-fuel ratio at the same load can be set to the lean side, and the fuel efficiency can be improved.

However, as shown in FIG. 7, the knocking limit T1 when energy is applied is lower than the knocking limit T0 when energy is not applied. It is possible to put out. Further, the inventors have found that there is an optimum in-cylinder pressure and in-cylinder temperature condition when applying the auxiliary energy.

[0007] Fig. 8 shows contour lines representing the fuel efficiency improvement rate ΔISFC with respect to the in-cylinder temperature T _tdc and the in-cylinder pressure P _tdc near the compression top dead center when auxiliary energy is applied. The in-cylinder pressure and temperature in the vicinity of the compression top dead center where the fuel efficiency is the highest are 4MP, respectively.
a, 730K. Unless energy supplementation is performed in the vicinity of the temperature and pressure conditions, an effective action such as improvement of combustion efficiency by application of supplementary energy cannot be expected.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide an in-cylinder air-fuel mixture with an auxiliary energy in a high fuel efficiency improving state while avoiding a knocking phenomenon, thereby increasing combustion efficiency and reducing fuel efficiency and emission. And a compression ignition type internal combustion engine.

[0009]

According to the first aspect of the present invention,
In order to solve the above problems, in a compression ignition type internal combustion engine that ignites and burns an air-fuel mixture by compression of a piston, pressure control means for controlling an in-cylinder pressure near compression top dead center to around 4 MPa; Temperature control means for controlling the in-cylinder temperature around 730K, energy applying means for applying auxiliary energy to the in-cylinder air-fuel mixture, and determining whether to apply auxiliary energy to the in-cylinder air-fuel mixture based on the required load When it is determined that auxiliary energy is to be applied, the pressure control means and the temperature control means control the in-cylinder pressure and the in-cylinder temperature, and the energy applying means applies auxiliary energy to the in-cylinder air-fuel mixture. And an auxiliary energy application control means for controlling the energy consumption.

According to a second aspect of the present invention, there is provided a compression ignition type internal combustion engine according to the first aspect.
In-cylinder pressure detecting means for detecting in-cylinder pressure, and in-cylinder temperature detecting means for detecting in-cylinder temperature, wherein the pressure control means includes an in-cylinder near a compression top dead center by the in-cylinder pressure detecting means. The gist is that the pressure detection value is controlled to be around 4 MPa, and the temperature control means controls the in-cylinder temperature detection value near the compression top dead center by the in-cylinder temperature detection unit to be around 730 K. I do.

According to a third aspect of the present invention, there is provided a compression ignition type internal combustion engine according to the first aspect, wherein:
Further comprising intake pressure detecting means for detecting intake pressure, intake air temperature detecting means for detecting intake air temperature, and polytropic index calculating means for calculating a polytropic index of the in-cylinder air-fuel mixture; And controlling the intake pressure so as to be a target intake pressure calculated based on the target in-cylinder pressure of 4 MPa near the point and the polytropic index, and the temperature control means controls the target in-cylinder temperature 730 near the compression top dead center.
The gist of the present invention is to control the intake air temperature so that the target intake air temperature is calculated based on K and the polytropic index.

According to a fourth aspect of the present invention, there is provided a compression ignition type internal combustion engine according to the third aspect, wherein:
The polytropic index calculating means includes a fuel injection amount detecting means for detecting a fuel injection amount and an air flow rate detecting means for detecting an intake air flow rate, and a polytropic index based on the detected fuel injection amount and the air flow rate. Is to be calculated.

According to a fifth aspect of the present invention, in the compression ignition type internal combustion engine according to any one of the first to fourth aspects, the auxiliary energy application control means has a load. The gist of the present invention is to stop the energy application when the determination value is exceeded.

According to a sixth aspect of the present invention, there is provided a compression ignition type internal combustion engine as set forth in any one of the first to fifth aspects, wherein an ignition plug is provided as the energy applying means. The gist is to provide auxiliary energy to the in-cylinder mixture by at least one or more discharges of the spark plug.

According to a seventh aspect of the present invention, there is provided a compression ignition type internal combustion engine according to any one of the first to fifth aspects, wherein a laser beam irradiation device is provided as the energy applying means. The gist is that auxiliary energy is given to the air-fuel mixture in the cylinder by the laser light irradiated by the laser irradiation device.

[0016]

According to the first aspect of the present invention, it is determined whether or not to apply auxiliary energy to the air-fuel mixture based on the required load.
The pressure control means and the temperature control means control the in-cylinder pressure near the compression top dead center and the in-cylinder temperature near 4 MPa and 730 K, and the energy applying means applies auxiliary energy to the in-cylinder air-fuel mixture. At the time of a high load that may cause a knocking phenomenon, the application of auxiliary energy is stopped to control the in-cylinder pressure and the in-cylinder temperature near the compression top dead center to high values of the energy assist effect without deteriorating the high load limit. Thus, there is an effect that improvement in fuel efficiency and reduction in emission can be realized at the same time.

According to the second aspect of the invention, in addition to the effect of the first aspect, the in-cylinder pressure detecting means for detecting the in-cylinder pressure and the in-cylinder temperature detecting means for detecting the in-cylinder temperature are provided. Further comprising controlling the in-cylinder pressure detection value near the compression top dead center by the in-cylinder pressure detection means to be around 4 MPa;
Since the in-cylinder temperature detected by the in-cylinder temperature detector near the compression top dead center is controlled to be around 730 K, the in-cylinder pressure and the in-cylinder temperature can be accurately reduced based on the detected values. There is an effect that the state can be controlled to be high.

According to the third aspect of the present invention, in addition to the effects of the first aspect, the intake pressure detecting means, the intake temperature detecting means, and the polytropic index calculating means for calculating the polytropic index of the in-cylinder mixture are provided. The pressure control means and the temperature control means calculate the target intake pressure and the target intake temperature based on the target in-cylinder pressure and the target in-cylinder temperature near the compression top dead center and the polytropic index, and become the target values. The intake pressure and the intake air temperature are controlled at the same time. Therefore, the intake pressure detection means and the intake air temperature detection means which are technically established and have high reliability without directly measuring the in-cylinder pressure and the in-cylinder temperature which are high temperature and high pressure. The effect that the in-cylinder pressure and the in-cylinder temperature in the vicinity of the compression top dead center can be accurately controlled with a relatively simple configuration using the above-described method.

According to a fourth aspect of the present invention, in addition to the effect of the third aspect of the present invention, the polytropic index calculating means includes a fuel injection amount detecting means and an air flow rate detecting means. Since the polytropic index is calculated from the injection amount and the air flow rate, there is an effect that an accurate polytropic index can be calculated according to the operation state.

According to the fifth aspect of the present invention, in addition to the effects of the first to fourth aspects of the present invention, the auxiliary energy application control means performs the energy application when the load exceeds a certain judgment value. Since the engine is stopped, the combustion speed at the time of high load is promoted, and it is possible to avoid occurrence of knocking.

According to the sixth aspect of the invention, in addition to the effects of the first to fifth aspects of the present invention, at least one or more discharges are performed by the ignition plug as the energy applying means to provide the auxiliary energy. Therefore, it is possible to provide a compression ignition type internal combustion engine equipped with an inexpensive, durable and reliable energy applying means using an ignition system in a technically completed area.

According to the seventh aspect of the invention, in addition to the effects of the first to fifth aspects, the auxiliary energy is applied by the laser beam irradiation device as the energy applying means. Auxiliary energy can be applied to the air-fuel mixture in a linear region instead of a point, and a wide range of the air-fuel mixture is activated, so that fuel efficiency can be further improved and exhaust gas can be further reduced. it can.

According to the seventh aspect of the present invention, a more effective energy assisting effect can be obtained by selectively using laser light in a wavelength band that easily excites the hydrocarbon fuel. .

[0024]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a system configuration diagram showing a configuration of a first embodiment of a compression ignition type internal combustion engine according to the present invention. The internal combustion engine of the present embodiment includes a combustion chamber 1, at least one intake port 2, an intake valve 3 located at an inlet of the combustion chamber 1 downstream of the intake port 2, and a piston 4.
At least one fuel injection valve 5 located at the intake port 2, an in-cylinder pressure sensor 6 for measuring an in-cylinder pressure,
An in-cylinder temperature sensor 7 for measuring an in-cylinder temperature, a spark plug 8 as an output of an auxiliary energy applying means, and an engine control unit (hereinafter abbreviated as ECU) 9
And at least one exhaust port 10 and exhaust port 1
0, an exhaust valve 11 located at a combustion chamber outlet, and a load sensor 12 for detecting an engine load such as an accelerator opening.
, A supercharger 13 located upstream of the intake port 2, an intake heater 14 located upstream of the intake port 2, and a crank angle sensor 15.

The supercharger 13 is, for example, a turbocharger or a supercharger. The intake heater 14 may be, for example, an electric heater, a heater that exchanges heat between engine cooling water and intake air, or an EGR device.

The ECU 9 compares the output signal of the load sensor 12 with a predetermined determination value, and determines whether or not the load exceeds the determination value.
1, a pressure control unit 32 that controls the supercharger 13 to control the in-cylinder pressure near the compression top dead center to around 4 MPa, and an intake heater 14 based on the determination result of the load determination unit 31. 730K in the cylinder near the compression top dead center
A temperature control unit 33 for controlling the vicinity of the vehicle and an ignition circuit which constitutes a part of the auxiliary energy applying means are built in and a load determination unit 31 is provided.
And an auxiliary energy application control unit 34 that controls the discharge of the ignition plug 8 based on the determination result.

Fuel such as gasoline is supplied from the fuel injection valve 5 at a time when the intake valve 3 is closed, that is, at a time other than the intake stroke. The fuel injection valve 5 is directed so that the injected fuel hits the intake valve 3 directly, and the injected fuel is promoted to be vaporized by the intake valve 3 sufficiently heated by the heat transmitted from the combustion chamber 1.

The fuel injection valve 5 may be provided at a position where fuel is directly injected into the cylinder. In the intake stroke in which the intake valve 3 is opened and fresh air is sucked into the combustion chamber 1, the fuel supplied from the fuel injection valve 5 is sufficiently mixed with the fresh air and spreads throughout the combustion chamber. Subsequently, the compressor enters the compression stroke, and the air-fuel mixture in the combustion chamber is compressed and heated by the rise of the piston 4, leading to ignition.

At this time, the output from the load sensor 12 is input to the ECU 9, and when the output from the load sensor 12 does not exceed a certain judgment value, the ECU 9 discharges the spark plug 8 at least once to assist. Perform energy application.

At this time, the crank angle sensor 15
, The pressure and temperature near the compression top dead center are detected from the pressure output from the in-cylinder pressure sensor 6 and the temperature output from the in-cylinder temperature sensor 7.
a, If the temperature is around 730K, the operation is continued. When the pressure has not reached 4 MPa and the temperature has not reached near 730 K, the supercharger 13 is operated by the output from the ECU 9 to increase the supercharging pressure until the target pressure value is reached.

Thereafter, when the temperature does not reach the target value, the intake heater 14 is operated, and the output of the intake heater 14 is increased until the temperature reaches the target temperature value. When the output from the load sensor 12 exceeds a certain judgment value, the ECU 9
The load determination unit 31 outputs an energy application stop signal to the auxiliary energy application control unit 34 to stop the discharge from the ignition plug 8.

FIG. 2 is a flowchart illustrating the flow of control in the first embodiment. In FIG. 2, first, the load sensor 12 detects a required load (Step 10, hereinafter, Step is abbreviated as S). The output of the load sensor 12 is compared with a predetermined determination value by a load determination unit 31 of the ECU 9. If the output exceeds the determination value, it is determined that energy assist is not performed. It is determined that assistance is provided (S12). When it is determined that the energy is to be assisted, the pressure near the compression top dead center is detected by the in-cylinder pressure sensor 6 (S14). Next, the pressure in the vicinity of the compression top dead center is the target pressure 4 by the pressure control unit 32.
It is determined whether the pressure is within a predetermined range from MPa (S16),
If it exceeds the predetermined range, the supercharger 13 is operated (S18), and the output of the supercharger 13 is adjusted (S20).
The process returns to the pressure detection near the compression top dead center by the in-cylinder pressure sensor 6.

If it is determined in S16 that the pressure near the compression top dead center is within a predetermined range from 4 MPa, then the temperature near the compression top dead center is detected by the in-cylinder temperature sensor 7 (S2).
2). Next, the temperature control unit 33 determines whether the temperature near the compression top dead center is within a predetermined range from the target temperature of 730K (S24), and if it is outside the predetermined range, activates the intake air heating 14 (S24). (S26), the output of the intake heater 14 is adjusted (S28), and the process returns to the detection of pressure near the compression top dead center by the in-cylinder pressure sensor 6 in S14.

Thus, the target in-cylinder pressure 4 near the compression top dead center
MPa, the target in-cylinder temperature is set to 730K, and under the condition that the energy assisting effect is in a high pressure and temperature range, a discharge instruction from the assisting energy application control unit 34;
Alternatively, the discharge is supplied at least once from the ignition plug 8 by directly supplying a discharge current, and auxiliary energy is given to the air-fuel mixture.

As described above, according to the first embodiment, the auxiliary energy supply is turned on in accordance with the required load.
/ OFF control, and in addition, by controlling the pressure and temperature near the compression top dead center to optimal values to maximize the effect of energy application, improve fuel efficiency and reduce emissions without deteriorating high load limits Can be realized. Further, according to the first embodiment, since the pressure and temperature near the top dead center of the direct compression are detected, the calculation load of the control system can be reduced.

FIG. 3 is a system configuration diagram showing the configuration of a second embodiment of the compression ignition type internal combustion engine according to the present invention. In the second embodiment, instead of directly measuring the in-cylinder pressure and the in-cylinder temperature, the in-cylinder pressure and the in-cylinder temperature near the compression top dead center due to the polytropic change of the air-fuel mixture from the intake pressure and the intake temperature are measured. When calculating and applying auxiliary energy, these in-cylinder pressure and in-cylinder temperature are optimal values of 4MP.
a, and is controlled to be 730K.

For this reason, instead of the in-cylinder pressure sensor 6 for measuring the in-cylinder pressure and the in-cylinder temperature sensor 7 for measuring the in-cylinder temperature in the first embodiment, the supercharger 13 is provided upstream of the intake port 2. An intake pressure sensor 16 located downstream of the intake port 2 and measuring intake pressure, an intake temperature sensor 17 located upstream of the intake port 2 and downstream of the heater 14 and measuring intake air temperature, and supplying fuel to the fuel injection valve 5. A point composed of a fuel flow meter 18 located in the middle of the fuel pipe 20 to be supplied and an air flow meter 19 located upstream of the supercharger 13 and the pressure and temperature near the compression top dead center are detected. The means is different from the configuration of the first embodiment.

Although the internal configuration of the ECU 9 is different, the load determining unit 31 and the auxiliary energy applying control unit 34 are the same, but a polytropic index calculating unit 35 is added, and the functions of the pressure control unit 36 and the temperature control unit 37 are the same. Different from one embodiment.

That is, based on the fuel amount measured by the fuel flow meter 18 and the intake air amount measured by the air flow meter 19, the polytropic index calculating section 35 calculates the polytropic index n of the air-fuel mixture which dynamically changes. . Then, using this polytropic index n, the pressure control unit 36 controls the supercharger 13 so that the in-cylinder pressure near the compression top dead center becomes 4 MPa, and the temperature control unit 37 similarly sets the compression top dead center The intake heater 14 is controlled so that the nearby in-cylinder temperature becomes 730K.

To calculate the polytropic index n, the constant pressure specific heat Cp is obtained from the air-fuel ratio (A / F) of the air-fuel mixture, and the constant pressure specific heat Cp is calculated.
The specific heat ratio κ is determined from p. Then, the coefficient α for obtaining the polytropic index n from the specific heat ratio κ is obtained by referring to a map as shown in FIG. 6, and the polytropic index n can be obtained by n = ακ.

Next, an equation for calculating the specific heat ratio κ of the air-fuel mixture from the air-fuel ratio will be described in detail. In the following description, the subscript AIR
Indicates the air, the suffix fuel indicates the fuel, and the suffix without the suffix indicates each value in the air-fuel mixture. The specific heat at constant pressure is Cp, the gas constant is Ro, the number of moles is n, and the molecular weight is m. The average molecular weights of air and fuel are constants, and if the air-fuel ratio A / F is determined, the molar ratio between air and fuel is determined. When the molar ratio is further determined, the specific heat Cp of the air-fuel mixture is determined, so that the specific heat ratio κ of the air-fuel mixture can be calculated.

[0042]

[Number 1] _{κ = Cp / (Cp-Ro} ) ... (1) CP = (n AIR · Cp AIR + n fuel · Cp fuel) / (n AI R + n fuel) ... (2) A / F = (n AIR · M _AIR ) / (n _fuel · m _fuel ) (3) Next, using the polytropic index n thus obtained, the pressure and temperature near the compression top dead center, the intake pressure (compression start pressure), and the intake air The relationship of the temperature (compression start temperature) is shown.

Since the cylinder volume (V1) when the compression bottom dead center or the intake valve is closed and the cylinder volume (V2) at the compression top dead center are known by the engine, the compression ratio ε = V1 / V2 is calculated from this. .

The compression start pressure is P1, the compression start volume is V1, the pressure target value at the compression top dead center is P2, the volume at the compression top dead center is V2, and the compression process is adiabatic change of perfect gas (ideal gas). Then, if it is assumed that PV ＾ n = constant polytrope change, the following equation (4) holds.

[0045]

P1V1 ＾ n = P2V2 ＾ n (4) From this, P2 = P1 (V1 / V2) ＾ n (5) P2 = P1 × ε ＾ n (6) where ε (= V1 / V2) is a compression ratio, and “＾” is a symbol indicating a power. n is the polytropic index.

From the equation (6), the pressure target value P at the compression top dead center is obtained.
The compression start pressure P1 required for 2 to be 4 MPa is obtained, and the supercharger 13 is controlled so that the intake pressure Pin output from the intake pressure sensor 16 becomes the required compression start pressure P1.

Here, the compression start pressure P1 is equal to the intake pressure Pin, but an appropriate correction may be made. Further, the required heating amount is calculated by the ECU 9 from the intake air temperature Tin, which is the output of the intake air temperature sensor 17, and the calculated polytropic index n so as to reach the temperature target value 730K of the compression top dead center.

The relationship between the compression start temperature T1 and the compression top dead center temperature T2 used for calculating the required heating amount is shown below.
This includes the characteristic equation (state equation) of complete gas PV = RT
From the above, respective characteristic expressions of the compression start point (P1, V1, T1) and the compression top dead center (P2, V2, T2) are as follows:

P1V1 = RT1 (7) P2V2 = RT2 (8) Therefore, T2 = T1 (P2V2) / (P1V1) (9) When P2 = P1 × ε ＾ n of Expression (6) is substituted into Expression (9), T2 = T1 × ε ＾ (n-1) ( 10) Alternatively, T1 = T2 × ε ＾ (1-n) (11) Here, ε is a compression ratio, and “＾” is a symbol indicating a power.
n is the polytropic index.

From the equation (11), the required compression start temperature T1 is calculated with the target temperature T2 of the compression top dead center = 730K. Then, the required heating amount for heating the intake air to T1 is calculated using the difference between the required compression start temperature T1 and the measured intake air temperature Tin, the intake air amount, and the specific heat (constant) of the air. You. Here, the intake air temperature Tin = the compression start temperature T1, but an appropriate correction may be made.

By controlling the outputs of the supercharger 13 and the intake heater 14 in accordance with the required supercharging pressure and the required heating amount, the same effects as in the first embodiment can be obtained. FIG. 4 shows a control flowchart of the second embodiment.

In FIG. 4, first, the load sensor 12 detects a required load (S50). The output of the load sensor 12 is compared with a predetermined determination value by a load determination unit 31 of the ECU 9. If the output exceeds the determination value, it is determined that energy assist is not performed. It is determined that assistance is provided (S52). When it is determined that the energy is to be supplemented, the intake air amount is determined by the air flow meter 19 (S54), and the fuel flow rate is determined by the fuel flow meter 18 (S5).
6) Detect each.

Next, based on the detected air flow rate and fuel flow rate, the polytropic index calculator 35 calculates a polytropic index n (S58). Next, the intake pressure is detected by the intake pressure sensor 16 (S60), the intake temperature is detected by the intake temperature sensor 17 (S62), and the pressure control unit 36 and the temperature control unit 37 respectively set the target pressure value near the compression top dead center (S60). The required supercharging pressure and the required heating amount are calculated based on the polytrope change from the pressure target pressure (4 MPa) and the same temperature target value (730 K) (S64).

Then, the supercharger 13 is operated (S6).
6) The output of the supercharger 13 is adjusted so as to attain the necessary supercharging pressure (S68), and the intake heater 14 is operated (S7).
0), the output of the intake heater is adjusted so as to attain the required heating amount (S72).

Thus, the target in-cylinder pressure 4 near the compression top dead center
MPa, the target in-cylinder temperature is set to 730K, and under the condition that the energy assisting effect is in a high pressure and temperature range, a discharge instruction from the assisting energy application control unit 34;
Alternatively, the discharge is supplied at least once from the ignition plug 8 by directly supplying a discharge current, and auxiliary energy is given to the air-fuel mixture.

The second embodiment uses a cylinder pressure sensor and a cylinder temperature sensor exposed to high temperature and high pressure,
Since the components used in general gasoline internal combustion engines, such as an intake pressure sensor and an intake temperature sensor, are adopted, the engine design is easy and cost-effective, and the reliability is excellent.

FIG. 5 shows a system configuration diagram of the third embodiment. This embodiment is different from the second embodiment in that the spark plug 8
Is replaced by a laser irradiation device 21. As the wavelength of the laser beam of the laser irradiation device, one having a wavelength at which the hydrocarbon fuel is easily excited is used. Thereby, an effect similar to that of the first embodiment can be obtained.

Further, in the third embodiment, not only energy assisting by points but also energy assisting by lines can be performed, so that energy assisting can be performed over a wide range of the air-fuel mixture in the combustion chamber. By selectively using laser light in a wavelength band that easily excites fuel, an effective auxiliary effect of energy can be obtained.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram showing a configuration of a first embodiment of a compression ignition type internal combustion engine according to the present invention.

FIG. 2 is a control flowchart illustrating the operation of the first embodiment.

FIG. 3 is a system configuration diagram showing a configuration of a second embodiment.

FIG. 4 is a control flowchart illustrating the operation of the second embodiment.

FIG. 5 is a system configuration diagram showing a configuration of a third embodiment.

FIG. 6 is a diagram illustrating a map for calculating a polytropic index.

FIG. 7 is a diagram illustrating a relationship between an air-fuel ratio with respect to a required load and a knocking limit when energy assist is turned ON / OFF.

FIG. 8 is a diagram showing contour lines of a fuel efficiency improvement rate ΔISFC with respect to a temperature T _tdc and a pressure P _tdc near the compression top dead center when auxiliary energy is applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Combustion chamber 2 Intake port 3 Intake valve 4 Piston 5 Fuel injection valve 6 In-cylinder pressure sensor 7 In-cylinder temperature sensor 8 Spark plug 9 Engine control unit (ECU) 10 Exhaust port 11 Exhaust valve 12 Load sensor 13 Supercharger 14 Intake Heater 15 Crank angle sensor 16 Intake pressure sensor 17 Intake temperature sensor 18 Fuel flow meter 19 Air flow meter 20 Fuel pipe 21 Laser irradiation device 31 Load determination unit 32 Pressure control unit 33 Temperature control unit 34 Auxiliary energy application control unit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) F02P 23/04 F02P 23/04 A F term (reference) 3G005 EA04 EA05 FA22 FA35 FA37 JA02 JA11 JA13 JA22 JA23 JA51 3G023 AA02 AA03 AA06 AA18 AB05 AB08 AC04 AC09 AD03 AF03

Claims (7)

[Claims] 1. A compression ignition type internal combustion engine in which an air-fuel mixture is ignited by compression of a piston and burns, a pressure control means for controlling an in-cylinder pressure near a compression top dead center to around 4 MPa, and a cylinder near a compression top dead center. Temperature control means for controlling the internal temperature to around 730K, energy applying means for applying auxiliary energy to the in-cylinder air-fuel mixture, and determining whether to apply auxiliary energy to the in-cylinder air-fuel mixture based on the required load, When it is determined that auxiliary energy is to be applied, the pressure control means and the temperature control means control the in-cylinder pressure and the in-cylinder temperature, and the energy applying means controls so as to apply auxiliary energy to the in-cylinder air-fuel mixture. A compression ignition type internal combustion engine, comprising: 2. An in-cylinder pressure detecting means for detecting an in-cylinder pressure, and an in-cylinder temperature detecting means for detecting an in-cylinder temperature, wherein the pressure control means includes a compression top dead center by the in-cylinder pressure detecting means. The temperature control means controls the detected in-cylinder temperature near the compression top dead center to be about 730K by the in-cylinder temperature detecting means. The compression ignition type internal combustion engine according to claim 1, wherein 3. The pressure control means further comprising: intake pressure detecting means for detecting an intake pressure; intake temperature detecting means for detecting an intake air temperature; and polytropic index calculating means for calculating a polytropic index of the in-cylinder air-fuel mixture. Is the target in-cylinder pressure 4 near the compression top dead center.
And controlling the intake pressure so as to be a target intake pressure calculated based on the MPa and the polytropic index. The temperature control means controls the target in-cylinder temperature 7 near the compression top dead center.
2. The compression ignition type internal combustion engine according to claim 1, wherein the intake air temperature is controlled so as to be a target intake air temperature calculated based on 30K and the polytropic index. 4. The method according to claim 1, wherein
It has a fuel injection amount detecting means for detecting a fuel injection amount and an air flow rate detecting means for detecting an intake air flow rate, and calculates a polytropic index based on the detected fuel injection quantity and the air flow rate. The compression ignition type internal combustion engine according to claim 3. 5. The compression ignition type according to claim 1, wherein said auxiliary energy application control means stops the application of energy when a load exceeds a certain judgment value. Internal combustion engine. 6. The cylinder according to claim 1, wherein an ignition plug is provided as the energy applying means, and auxiliary energy is applied to the air-fuel mixture in the cylinder by at least one discharge of the ignition plug. The compression ignition type internal combustion engine according to claim 1. 7. The apparatus according to claim 1, further comprising a laser light irradiating device as said energy applying means, wherein auxiliary energy is applied to the air-fuel mixture in the cylinder by a laser beam irradiated by said laser irradiating device. A compression ignition type internal combustion engine according to any one of the preceding claims.