JP2015075078A - Control unit for compression ignition internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control unit for a compression ignition internal combustion engine which can change the compression ratio without a mechanical construction changing a relative position between a cylinder block and a crank case.SOLUTION: A compression ignition internal combustion engine 1 includes a water injection valve 42 which can supply liquid water of a prescribed temperature or less into a combustion chamber 6, and water supply control means 50 which controls the water injection valve 42 so that an amount of water corresponding to a required compression ratio is supplied into the combustion chamber 6 under the condition in which the temperature in the combustion chamber 6 is less than the prescribed temperature.

Description

  The present invention relates to a control device applied to a compression ignition internal combustion engine capable of changing a compression ratio.

  It is equipped with a variable compression ratio mechanism that can change the volume in the cylinder at the top dead center by changing the relative position of the cylinder block and crankcase in the cylinder axis direction, and controls the variable compression ratio mechanism according to operating conditions. A control device for an internal combustion engine capable of changing the compression ratio is known (see Patent Document 1). In addition, there are Patent Documents 2 to 4 as prior art documents related to the present invention.

JP 2012-233439 A JP 2010-138737 A JP 2007-247588 A Japanese Patent Laid-Open No. 10-318049

  If a variable compression ratio mechanism that changes the relative position between the cylinder block and the crankcase is provided, the drive mechanism for moving the cylinder block is separated from the cylinder block and the crankcase is used. The structure of the mechanism becomes complicated.

  Accordingly, an object of the present invention is to provide a control device for a compression ignition internal combustion engine that can change the compression ratio without adopting a mechanical configuration that changes the relative position between the cylinder block and the crankcase.

  The control apparatus for a compression ignition internal combustion engine of the present invention is applied to a compression ignition internal combustion engine having water supply means capable of supplying liquid water into a combustion chamber at a predetermined temperature or lower, and the temperature in the combustion chamber is less than the predetermined temperature. And a water supply control means for controlling the water supply means so as to supply an amount of water corresponding to the required compression ratio into the combustion chamber (Claim 1).

  According to the control apparatus for a compression ignition internal combustion engine of the present invention, when water is supplied into the combustion chamber in a state where the temperature in the combustion chamber is equal to or lower than a predetermined temperature, the water is maintained in a liquid state. The same effect as that in which the volume of the combustion chamber is reduced by the volume occupied by. Accordingly, the compression ratio can be changed according to the amount of water supplied to the combustion chamber without adopting a mechanical configuration that changes the relative position between the cylinder block and the crankcase.

The figure which showed the whole structure of the compression ignition internal combustion engine to which the control apparatus which concerns on one form of this invention was applied. The figure which showed the cross section cut | disconnected by the plane along the centerline of the cylinder of the compression ignition internal combustion engine of FIG. The flowchart which showed an example of the control routine which ECU performs. The figure which showed the relationship between an engine speed and the water injection quantity required in order to make a geometric compression ratio into 20. FIG. The flowchart which showed the control routine which ECU performs in a 2nd form. The flowchart which showed the control routine which ECU performs in a 3rd form. The figure which showed the relationship between atmospheric pressure and altitude. The figure which showed the relationship between an altitude and the water injection quantity etc. which a water injection valve injects. The flowchart which showed the subroutine of FIG.

(First form)
A compression ignition internal combustion engine (hereinafter referred to as an internal combustion engine) 1 shown in FIG. 1 is mounted on a vehicle (not shown) as a driving power source. The internal combustion engine 1 is configured as an in-line four-cylinder internal combustion engine in which four cylinders 2 are arranged in one direction. As shown in FIG. 2, the internal combustion engine 1 includes a cylinder block 3 in which a cylinder 2 is formed, and a cylinder head 4 that closes an opening of the cylinder 2. A piston 5 is inserted into the cylinder 2, and the piston 5 can reciprocate in the direction of the center line in the cylinder 2. FIG. 2 shows a state where the piston 5 is located at the top dead center. A combustion chamber 6 is formed as a recess on the top surface of the piston 5 facing the cylinder 2. The fuel injection valve 7 is provided in the cylinder head 4 with its tip facing the center of the combustion chamber 6. When the piston 5 is positioned near the top dead center, the fuel injection valve 7 injects fuel into the combustion chamber 6. The glow plug 8 is provided on the cylinder head 4 with its tip protruding into the combustion chamber 6. By heating the glow plug 8, the temperature in the cylinder 2 can be raised. The volume in the cylinder 2 at the top dead center is 35.7 mL, and the stroke volume of the cylinder 2 is 500 mL. Therefore, the geometric compression ratio representing the ratio of the volume at the bottom dead center to the volume at the top dead center is 15.

  As shown in FIG. 1, an intake passage 10 and an exhaust passage 11 are connected to each cylinder 2. The internal combustion engine 1 is equipped with a turbocharger 12 that supercharges intake air using exhaust energy. The intake passage 10 is provided with an intake manifold 13, and intake air flowing through the intake passage 10 is distributed by the intake manifold 13 and is filled in each cylinder 2. The exhaust passage 11 includes an exhaust manifold 14, a diesel particulate filter 15 and a catalyst 16. Exhaust gas discharged from each cylinder 2 is collected by an exhaust manifold 14, and the collected exhaust gas is discharged into the atmosphere after particulate matter is removed by a diesel particulate filter 15 and harmful substances are removed by a catalyst 16. .

  The internal combustion engine 1 is provided with a first EGR device 20 and a second EGR device 30 as EGR devices that take out a part of the exhaust gas from the exhaust passage 11 and recirculate it as EGR gas in the intake passage 10. The first EGR device 20 includes a first EGR passage 21 that extracts a part of exhaust gas from the exhaust passage 11 as EGR gas and guides it to the intake passage 10, and a first EGR valve 22 that can adjust the flow rate of the EGR gas flowing through the first EGR passage 21. I have. Similarly, the second EGR device 30 includes a second EGR passage 31 and a second EGR valve 32 that can adjust the flow rate of the EGR gas flowing through the second EGR passage 31. Further, an EGR cooler passage 33 is branched from the exhaust passage 11 downstream from the catalyst 16, and an EGR cooler 34 is provided in the EGR cooler passage 33. The exhaust gas passing through the EGR cooler passage 33 is cooled by the EGR cooler 34 and then merged into the exhaust passage 11. An EGR cooler valve 35 is provided at a position where the EGR cooler passage 33 and the exhaust passage 11 merge. The EGR cooler valve 35 can adjust the flow rate of the exhaust gas flowing through the EGR cooler passage 33.

  When the temperature of the exhaust gas passing through the EGR cooler 34 decreases so as to straddle the dew point temperature inside the EGR cooler 34, the water vapor in the exhaust gas is condensed (condensed) in the EGR cooler 34 and becomes water. The water condensed by the EGR cooler 34 is stored in the condensed water tank 40. The condensed water tank 40 is provided with a water level sensor 41 that can detect the amount of stored water. The intake manifold 13 is provided with a water injection valve 42 as water supply means. The water stored in the condensed water tank 40 is supplied to the water injection valve 42 via the water supply pipe 43. The water supply pipe 43 is provided with a water injection pump 44 for supplying water stored in the condensed water tank 40 to the water injection valve 43. When the water injection valve 42 injects water into the intake manifold 13, the injected water is sucked into the cylinder 2 together with the intake air flowing through the intake manifold 13, so that water is supplied into the combustion chamber 6. If the temperature in the combustion chamber 6 is a low temperature that does not vaporize water, when water is supplied into the combustion chamber 6, the volume of the combustion chamber 6 is reduced by the volume occupied by liquid water in the combustion chamber 6. The same effect as that which became. Therefore, the compression ratio of the cylinder 2 can be changed according to the amount of water supplied by the water injection valve 42.

  Control of each part of the internal combustion engine 1 is controlled by an engine control unit (ECU) 50 configured as a computer. The ECU 50 includes a microprocessor and peripheral devices such as RAM and ROM necessary for its operation. The ECU 50 performs various controls on the water injection valve 42, the water injection pump 44, the glow plug 8, and the like. The ECU 50 receives output signals from the water level sensor 41, the atmospheric pressure sensor 51, the engine outlet water temperature sensor 52, the crank angle sensor 53, and the like. The atmospheric pressure sensor 51 is installed in a place with little temperature change in the engine room, and can detect the atmospheric pressure. The engine outlet water temperature sensor 52 can detect the temperature of engine cooling water that has passed through the water jackets of the cylinder block 3 and the cylinder head 4. Based on the output of the crank angle sensor 53, the engine speed (engine speed) can be detected.

  The internal combustion engine 1 ignites the fuel by compressing the air taken into the cylinder 2 to a high temperature. When the internal combustion engine 1 is started in a state where the temperature in the combustion chamber 6 is low, the intake air is compressed in the cylinder 2. Even then, the piston 5, the cylinder head 4 and the cylinder block 3 are deprived of heat, and the intake air does not reach the temperature at which the fuel is ignited, which may cause a starting failure. Therefore, in the present embodiment, when the temperature of the engine cooling water as the temperature in the combustion chamber 6 is less than a predetermined temperature of 10 ° C., the compression ratio is increased by the water injection by the water injection valve 42 or the glow plug. By heating 8 and raising the temperature in the cylinder 2, the occurrence of a start failure of the internal combustion engine 1 is suppressed.

  FIG. 3 is a flowchart illustrating an example of a control routine executed by the ECU 50. The program of the control routine of FIG. 3 is held in the ECU 50 and is read and executed when starting the internal combustion engine 1. The ECU 50 functions as water supply control means according to the present invention by executing the control routine of FIG.

  In this control routine, the ECU 50 first detects the temperature of the engine cooling water as a physical quantity representative of the temperature in the combustion chamber 6 from the output of the engine outlet water temperature sensor 52 in step S11. This is because there is no particular problem even if the temperature in the combustion chamber 6 and the temperature of the engine coolant are handled equally. In the next step S12, the ECU 50 determines whether the temperature of the engine coolant is less than a predetermined temperature of 10 ° C. When the temperature of the engine cooling water is less than 10 ° C., the process proceeds to step S13 for low temperature start control. On the other hand, if the engine coolant temperature is not less than 10 ° C., the process proceeds to step S17, the internal combustion engine 1 is started without operating the water injection valve 42 and the glow plug 8, and the current routine is terminated.

  In step S13, the ECU 50 determines whether the temperature of the engine coolant is 2 ° C. or higher. If the engine coolant temperature is 2 ° C. or higher, the process proceeds to step S14. On the other hand, when the temperature of the engine coolant is not 2 ° C. or higher, the process proceeds to step S15.

  In step S <b> 14, the ECU 50 detects the amount of water stored in the condensed water tank 40 from the output of the water level sensor 41 and determines whether the amount of stored water is one third or more of the volume of the condensed water tank 40. If the amount of stored water is 1/3 or more of the volume of the condensed water tank 40, the process proceeds to step S16. On the other hand, if the amount of stored water is not more than one third of the volume of the condensed water tank 40, the process proceeds to step S15.

  In step S <b> 15, the ECU 50 starts the internal combustion engine 1 after heating the glow plug 8. Then, the current routine is terminated.

  In step S16, when the internal combustion engine 1 is started, the ECU 50 starts the water injection pump 44 and causes the water injection valve 42 to inject water at a predetermined water injection amount. The water injection amount is within a range in which the pressure in the cylinder 2 at the top dead center does not increase as the internal combustion engine 1 is broken, and the temperature of the gas in the cylinder 2 at the top dead center is increased by compression to a temperature at which the fuel can be ignited. Within range. For example, the liquid water occupies 8.7 mL of the 35.7 mL volume in the cylinder 2 at the top dead center, so that the volume occupied by the gas in the cylinder 2 at the top dead center is 27.0 mL. When the compression ratio is calculated, 19.5 is obtained. If water is injected into the water injection valve 42 so that the geometric compression ratio becomes 19.5, the pressure in the cylinder 2 at the top dead center does not increase as the internal combustion engine 1 is broken, and the fuel can be ignited. The temperature of the gas in the cylinder 2 can be raised to the temperature. In order for liquid water to occupy 8.7 mL of the volume in the cylinder 2, if the engine speed at the start is 300 rpm, that is, 2.5 cycles per second, one injection valve 42 supplies water to the four cylinders 2. Since it is supplied, the water injection valve 42 is injected at a water injection amount of 87 mL per second.

  When the ECU 50 executes the control routine of FIG. 3 described above, even if the internal combustion engine 1 is started in a state where the temperature in the combustion chamber 6 where the temperature of the engine cooling water is less than 10 ° C. is low, a start failure occurs. Can be suppressed.

(Second form)
Next, a second embodiment of the present invention will be described with reference to FIGS. This form has the same configuration as the first form except that the control method of the water injection valve 42 by the ECU 50 is different. Hereinafter, characteristic portions of the second embodiment will be described, and portions common to the first embodiment will be denoted by the same reference numerals in the drawings and description thereof will be omitted.

  Although the internal combustion engine 1 includes a turbocharger 12, the pressure in the cylinder 2 is low when used under the condition that the supercharging of the intake air does not work. Therefore, the fuel injected by the fuel injection valve 7 jumps too much to the wall surface of the combustion chamber 6. Adhere to. Further, when the temperature in the combustion chamber 6 is low, the fuel adhering to the wall surface of the combustion chamber 6 may be discharged from the cylinder 2 without burning, and the HC emission amount may increase. Therefore, in this embodiment, the use condition of the internal combustion engine 1 determined by the engine speed and the fuel injection amount is within a certain range, and the temperature of the engine coolant as the temperature in the combustion chamber 6 is a predetermined temperature of 60 ° C. If it is less than this, HC emission is suppressed by increasing the compression ratio by water injection by the water injection valve 42.

  FIG. 4 shows a water injection amount of 20 when the geometric compression ratio is calculated by taking the volume excluding the volume occupied by liquid water out of 35.7 mL as the volume in the cylinder 2 at the top dead center as the volume occupied by the gas. And the relationship between the engine speed and the engine speed. This relationship is obtained in advance by numerical calculation or the like and is stored in the ECU 50.

  FIG. 5 is a flowchart illustrating an example of a control routine executed by the ECU 50. The control routine program shown in FIG. 5 is held in the ECU 50, read out in a timely manner, and repeatedly executed at predetermined intervals. The ECU 50 functions as water supply control means according to the present invention by executing the control routine of FIG.

  In this control routine, first in step S21, the ECU 50 detects the temperature of the engine coolant as a physical quantity representative of the temperature in the combustion chamber 6 from the output of the engine outlet water temperature sensor 52. This is because there is no particular problem even if the temperature in the combustion chamber 6 and the temperature of the engine coolant are handled equally. Then, the ECU 50 detects the engine speed from the output of the crank angle sensor 53. In the next step S22, the ECU 50 has an engine cooling water temperature of less than a predetermined temperature of 60 ° C., an engine speed of more than 500 rpm and less than 2000 rpm, and a fuel injection amount of one cycle in one cylinder 2 is 20. Judge whether it is less than cubic mm. If all these conditions are satisfied, the process proceeds to step S23. On the other hand, if none of these conditions is satisfied, the current routine is terminated.

  In step S <b> 23, the ECU 50 detects the amount of water stored in the condensed water tank 40 from the output of the water level sensor 41 and determines whether the amount of stored water is one third or more of the volume of the condensed water tank 40. If the amount of stored water is not less than one third of the volume of the condensed water tank 40, the process proceeds to step S24. On the other hand, if the amount of stored water is not more than one third of the volume of the condensed water tank 40, the process returns to step S21.

  In step S24, the ECU 50 calculates the water injection amount according to the engine speed from the relationship between the water injection amount and the engine speed necessary for setting the geometric compression ratio stored in advance in the ECU 50 to 20. To do. Then, the ECU 50 causes the water injection valve 42 to inject the calculated water injection amount. Then, the process returns to step S21.

  By executing the control routine of FIG. 5 described above by the ECU 50, it is possible to suppress the discharge of HC even if the internal combustion engine 1 is used under the condition that the supercharging of the intake air does not work.

(Third form)
Next, a third embodiment of the present invention will be described with reference to FIG. 6, FIG. 7, FIG. 8, and FIG. This form has the same configuration as the first form except that the control method of the glow plug 8 and the water injection valve 42 by the ECU 50 is different. Hereinafter, characteristic portions of the third embodiment will be described, and portions common to the first embodiment will be denoted by the same reference numerals and description thereof will be omitted.

  As described in the first embodiment, when the internal combustion engine 1 is started in a state where the temperature in the combustion chamber 6 is low, the intake air does not reach the temperature at which the fuel is ignited, which may cause a start failure. Further, when the internal combustion engine 1 is started at a point where the altitude is high and the atmospheric pressure is low, the intake air compressed in the cylinder 2 does not reach a temperature at which the fuel is ignited, which may cause a start failure. Therefore, in the present embodiment, when the temperature of the engine cooling water as the temperature in the combustion chamber 6 is less than 10 ° C., which is a predetermined temperature, or when the altitude is 1000 m or more, the compression ratio is determined by water injection by the water injection valve 42. Is increased, or the glow plug 8 is heated to increase the temperature in the cylinder 2, thereby suppressing the start failure of the internal combustion engine 1.

  FIG. 6 is a flowchart illustrating an example of a control routine executed by the ECU 50. The program of the control routine of FIG. 6 is held in the ECU 50 and is read out and executed when the internal combustion engine 1 is started.

  In this control routine, first in step S31, the ECU 50 detects the temperature of the engine cooling water as a physical quantity representative of the temperature in the combustion chamber 6 from the output of the engine outlet water temperature sensor 52. This is because there is no particular problem even if the temperature in the combustion chamber 6 and the temperature of the engine coolant are handled equally. The ECU 50 detects the atmospheric pressure P (hPa) from the output of the atmospheric pressure sensor 51 and calculates the altitude h (m) from the following relational expression 1.

  h = (1003.2-P) /0.0992 ... 1

  FIG. 7 is a diagram showing this relational expression. This relational expression is stored in the ECU 50 in advance. In the next step S32, the ECU 50 determines whether the engine coolant temperature is lower than a predetermined temperature of 10 ° C. and the altitude is 1000 m or higher. If the engine coolant temperature is less than 10 ° C. and the altitude is 1000 m or higher, the process proceeds to step S33. On the other hand, when the water temperature of the engine cooling water is not lower than 10 ° C. or the altitude is not 1000 m or higher, the process proceeds to step S37.

  In step S33, the ECU 50 determines whether the engine coolant temperature is 2 ° C. or higher. If the engine coolant temperature is 2 ° C. or higher, the process proceeds to step S34. On the other hand, if the engine coolant temperature is not 2 ° C. or higher, the process proceeds to step S35.

  In step S <b> 34, the ECU 50 detects the amount of water stored in the condensed water tank 40 from the output of the water level sensor 41 and determines whether the amount of stored water is one third or more of the volume of the condensed water tank 40. If the amount of stored water is not less than one third of the volume of the condensed water tank 40, the process proceeds to step S36. On the other hand, if the amount of stored water is not more than one third of the volume of the condensed water tank 40, the process proceeds to step S35.

  In step S35, the ECU 50 starts the internal combustion engine 1 after heating the glow plug 8. Then, the current routine is terminated.

  In step S36, the ECU 50 calculates a water injection amount corresponding to the altitude from the relationship between the altitude h and the water injection amount F shown in FIG. For example, when the altitude is 2000 m or more and less than 3000 m, the water injection amount is 87 mL per second. Then, the ECU 50 starts the internal combustion engine 1 after heating the glow plug 8, starts the water injection pump 44 when the internal combustion engine 1 is started, and causes the water injection valve 42 to inject the calculated water injection amount. Then, the current routine is terminated.

  The water injection amount F in FIG. 8 is obtained in advance by the following calculation. As shown in FIG. 8, when the altitude h is 1000 m or more and less than 2000 m, the water injection amount F is calculated with the control altitude H being 1500 m. Similarly, when the altitude h is 2000 m or more and less than 3000 m, the control altitude H is 2500 m, when the altitude h is 3000 m or more and less than 4000 m, the control altitude H is 3500 m, and when the altitude h is 4000 m or more and less than 5000 m, the control altitude H is Is 4500 m, and the water injection amount F is calculated.

  When the altitude is high and the atmospheric pressure is low, by reducing the volume occupied by gas in the cylinder 2 at the top dead center and increasing the compression ratio, the temperature and pressure in the cylinder 2 at the top dead center are the same as the lowland at an altitude of 0 m. Can be. The value calculated for the altitudes of 1500 m, 2500 m, 3500 m and 4500 m for the volume occupied by the gas in the cylinder 2 at the top dead center where the temperature and pressure in the cylinder 2 can be the same as the low altitude of 0 m is shown in FIG. C (mL). If liquid water occupies the volume V (mL) in FIG. 8 in the volume 35.7 mL in the cylinder 2 at the top dead center, the volume occupied by the gas in the cylinder 2 at the top dead center is the volume C in FIG. can do. For example, in the case of an altitude of 2500 m, water occupies 8.7 mL of the volume V in the volume in the cylinder 2, so that the temperature and pressure in the cylinder 2 at the top dead center can be made the same as a lowland at an altitude of 0 m. . Assuming that the engine speed at start-up is 300 rpm, that is, 2.5 cycles per second, the internal combustion engine 1 has four cylinders 2, and one water injection valve 42 provided in the intake manifold 13 is provided in all four cylinders 2. Since water is supplied, the water injection amount F (mL / s) for occupying the volume V (mL) in the cylinder 2 can be calculated by the following equation 2.

  F = 2.5 × 4 × V ・ ・ ・ ・ ・ ・ 2

  In step S37, the ECU 50 determines whether the temperature of the engine cooling water is less than a predetermined temperature of 10 ° C. When the engine coolant temperature is lower than 10 ° C., low temperature start control is performed, which is control of a portion surrounded by a broken line in FIG. Then, the current routine is terminated. On the other hand, if the engine coolant temperature is not less than 10 ° C., the process proceeds to step S38.

  In step S38, the ECU 50 determines whether the altitude is 1000 m or higher. If the altitude is not 1000 m or higher, the process proceeds to step S39, the internal combustion engine 1 is started without operating the water injection valve 42 and the glow plug 8, and the current routine is terminated. On the other hand, when the altitude is 1000 m or more, the process proceeds to step S40 and highland start control is performed.

  FIG. 9 shows the processing content of step S40. In step S41, the ECU 50 detects the amount of water stored in the condensed water tank 40 from the output of the water level sensor 41, and determines whether the amount of stored water is one third or more of the volume of the condensed water tank 40. If the amount of stored water is not more than one third of the volume of the condensed water tank 40, the process proceeds to step S42. On the other hand, if the amount of stored water is 1/3 or more of the volume of the condensed water tank 40, the process proceeds to step S43.

  In step S42, the ECU 50 starts the internal combustion engine 1 after heating the glow plug 8. Then, the current routine is terminated.

  In step S43, the ECU 50 calculates a water injection amount corresponding to the altitude from the relationship between the altitude h and the water injection amount F shown in FIG. The ECU 50 starts the water injection pump 44 when starting the internal combustion engine 1 and causes the water injection valve 42 to inject the calculated water injection amount. Then, the current routine is terminated.

  When the ECU 50 executes the control routine of FIGS. 6 and 9 described above, the internal combustion engine 1 is started in a state where the temperature in the combustion chamber 6 where the temperature of the engine cooling water is less than 10 ° C. is low, Even when the internal combustion engine 1 is started at a high altitude of 1000 m or more, the occurrence of a start failure of the internal combustion engine 1 can be suppressed. The ECU 50 functions as water supply control means according to the present invention by executing the control routines of FIGS. 6 and 9.

  The present invention is not limited to the above embodiments, and can be implemented in various forms within the scope of the gist of the present invention. In each of the above embodiments, the temperature of the engine coolant is used as a physical quantity representing the temperature in the combustion chamber, but this is only an example. For example, the temperature of the engine oil can be used as a physical quantity representative of the temperature in the combustion chamber. Further, the temperature in the combustion chamber can be directly measured and acquired, or the temperature in the combustion chamber can be acquired by estimation based on the operating state of the internal combustion engine.

  In the above embodiments, the present invention is applied to a four-cylinder internal combustion engine, but the present invention can be applied regardless of the number of cylinders. In the above embodiments, the present invention is applied to an internal combustion engine equipped with a turbocharger. However, the present invention can also be applied to an internal combustion engine not equipped with a turbocharger. In the above embodiments, the present invention is applied to an internal combustion engine equipped with an EGR device. However, the present invention can also be applied to an internal combustion engine not equipped with an EGR device.

DESCRIPTION OF SYMBOLS 1 Compression ignition internal combustion engine 6 Combustion chamber 42 Water injection valve (water supply means)
50 ECU (water supply control means)

Claims (1)

Applied to a compression ignition internal combustion engine comprising water supply means capable of supplying liquid water into a combustion chamber at a predetermined temperature or lower;
Water supply control means is provided for controlling the water supply means so that an amount of water corresponding to a required compression ratio is supplied into the combustion chamber under a condition that the temperature in the combustion chamber is lower than the predetermined temperature. A control apparatus for a compression ignition internal combustion engine.

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