JP2005171867A - Cylinder direct injection continuous combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylinder direct injection continuous combustion engine capable of solving a problem of fouling, suppressing degradation of emission and providing sufficient output. <P>SOLUTION: In the cylinder direct injection combustion engine continuously injecting fuel from a fuel injection valve 22 toward an ignition plug 30 in a combustion chamber during a compression stroke and making spray continuously ignited and burnt, a water temperature sensor 34 detecting temperature of the engine is provided and an injection style control means making fuel injection from the fuel injection valve 22 in a style of multiplex fuel injection or pilot injection and main injection when engine temperature is a predetermined value or less. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an in-cylinder fuel injection internal combustion engine that injects and supplies fuel into a combustion chamber, and more particularly, to inject and supply fuel from a fuel injection valve into a combustion chamber having an ignition source so as to perform continuous flame combustion. The present invention relates to a direct injecting continuous combustion engine.

  Conventionally, as the in-cylinder direct injection continuous combustion engine, for example, the one described in Non-Patent Document 1 is known. In this non-patent document 1, an air swirl is generated in a constant circumferential direction in the combustion chamber of a two-valve engine, and the fuel injected from a fuel injection valve attached to the side of the head immediately before ignition is swirled. It is vaporized and mixed by being put on, and is continuously ignited by a spark plug arranged in the vicinity of the injection valve so as to perform continuous flame combustion, thereby realizing knock-free combustion.

Paper "ELIMINATION OF COMBUSTION KNOCK -TEXACO COMBUSTION PROCESS" SAE Quarterly Transaction (1950)

  By the way, in the engine described in Non-Patent Document 1, the fuel is continuously injected from the fuel injection valve attached to the side surface of the head toward the ignition plug, and the spray is continuously ignited. To make it burn. Therefore, the fuel spray is continuously applied to the spark plug. Therefore, when the spark plug is not sufficiently heated, such as when the engine is cold, or when the spark plug is cooled by a large amount of fuel injection, Since the fuel covers the plug and its evaporation is not completely performed, smoldering or the like may occur as a result. As a result, there has been a problem that the engine emission deteriorates and sufficient output cannot be obtained.

  An object of the present invention is to provide an in-cylinder direct injection continuous combustion engine that can solve the conventional smoldering problem, suppress the deterioration of emission, and obtain a sufficient output.

  A direct injection continuous combustion engine according to an embodiment of the present invention that achieves the above object continuously injects fuel from a fuel injection valve toward an ignition source in a combustion chamber in a compression stroke, and continuously sprays the fuel. An in-cylinder direct injection continuous combustion engine that is ignited and combusted is provided with engine temperature detection means for detecting the temperature of the engine, and when the engine temperature is equal to or lower than a predetermined value based on the detection result by the engine temperature detection means, The present invention is characterized in that there is provided an injection form control means for making fuel injection from the injection valve into a form of multiple fuel injection or pilot injection and main injection.

A direct injection continuous combustion engine according to another embodiment of the present invention that achieves the above object continuously injects fuel from a fuel injection valve toward an ignition source in a combustion chamber in a compression stroke, and continuously sprays the fuel. An in-cylinder direct injection continuous combustion engine that is ignited and combusted is provided with an engine temperature detecting means for detecting the engine temperature and an engine load detecting means for detecting the engine load, the engine temperature detecting means and the engine load detecting When the engine temperature is equal to or lower than a predetermined value and the engine load is higher than the predetermined value based on the detection result by the means, the fuel injection from the fuel injection valve is in the form of multiple fuel injection or pilot injection and main injection. Control means is provided.
The main injection may be multiple fuel injection.

  According to the in-cylinder direct injection continuous combustion engine according to one aspect of the present invention, normally, in the compression stroke, fuel is injected from the fuel injection valve toward the ignition source, and the spray mixed with air is continuously produced. It is ignited and burned. Therefore, when the engine temperature is not more than a predetermined value as a result of detection by the engine temperature detecting means, the fuel injection from the fuel injection valve is changed to the form of multiple fuel injection or pilot injection and main injection by the injection form control means. Be changed. Therefore, the temperature of the ignition source is appropriately maintained, and good ignition or ignition and continuous combustion are realized.

Further, according to the in-cylinder direct injection continuous combustion engine according to another aspect of the present invention, when the engine temperature is equal to or lower than the predetermined value and the engine load is higher than the predetermined value, the injection form control means causes the fuel from the fuel injection valve to The injection is changed to a form of multiple fuel injection or pilot injection and main injection. Accordingly, the temperature is appropriately maintained without excessively cooling the ignition source, and good ignition or ignition and continuous combustion are realized.
As a result, in any embodiment of the present invention, the deterioration of emissions is suppressed, and a sufficient output can be obtained.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of a direct injection continuous combustion engine according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a cross-sectional view of a principal part showing a schematic configuration of an in-cylinder direct injection continuous combustion engine (hereinafter referred to as an engine) 10 to which the present invention is applied. The engine 10 shown in FIG. 1 is a four-cycle water-cooled gasoline engine. The engine 10 includes a cylinder block 12 in which a plurality of cylinders and cooling water passages are formed, and a cylinder head 14 fixed to the upper portion of the cylinder block 12. A crankshaft 16 serving as an engine output shaft is rotatably supported on the cylinder block 12, and this crankshaft is connected via a connecting rod to a piston 18 slidably loaded in each cylinder.

  A timing rotor having a plurality of teeth formed on the periphery thereof is attached to the end of the crankshaft 16, and an electromagnetic pickup is attached to the cylinder block 12 near the timing rotor. The timing rotor and the electromagnetic pickup constitute an engine speed sensor 20.

  A combustion chamber surrounded by the top surface of the piston 18 and the inner wall surface of the cylinder head 14 is formed above the piston 18 of each cylinder. A fuel injection valve 22 is attached to the cylinder head 14 so as to inject toward the center of the combustion chamber of each cylinder. The fuel injection valve 22 is connected to a delivery pipe (not shown) and is connected. Fuel supplied from the illustrated fuel tank is pressurized and supplied by a fuel pump.

  Further, in the portion of the cylinder head 14 facing the combustion chamber of each cylinder, two open ends of the intake port 24 are formed in parallel, and two open ends of the exhaust port 26 are also formed in parallel. Yes. The cylinder head 14 is provided with an intake valve 25 that opens and closes each open end of the intake port 24 and an exhaust valve 27 that opens and closes each open end of the exhaust port 26 so as to freely advance and retract. Further, an ignition plug 30 as an ignition source in which an ignition gap is located at a portion of the cylinder head 14 facing the upper part of the combustion chamber of each cylinder is disposed substantially on the cylinder axis.

  As shown in FIG. 2, the fuel injection valve 22 is arranged so that the spray is injected in the direction between the intake valves 25 arranged in parallel when viewed from the cylinder axial direction, and the spray of high-pressure fuel is almost the cylinder shaft. A spark plug 30 arranged on the line is reached. On the other hand, with respect to the spark plug 30, the cylinder head combustion chamber surface that forms the combustion chamber on the opposite side of the fuel injection valve 22 has a substantially fan-like shape having a required 40 T between the exhaust valves 27 that are parallel to each other when viewed from the cylinder axial direction. A diversion bank 40 is provided.

The diversion bank 40 is formed so that its cross section gradually changes from a triangle to a fine trapezoid and a thick trapezoid as it goes from the main 40T toward the cylinder side wall, and partially surrounds the exhaust valve 27. As a result, when the exhaust valve 27 is lifted, each opening end of the exhaust port 26 is partially masked by the diversion bank 40. The height of the diversion bank 40 is substantially equal to the lower surface of the cylinder head 14.
A substantially conical or partially spherical cavity 45 is provided on the top surface of the piston 18 forming the combustion chamber.

  An intake throttle valve (not shown) is provided in the intake passage upstream of the intake port 24 to control the output of the engine 10. An intake negative pressure sensor 32 for detecting the engine load is provided in the intake passage downstream of the intake throttle valve, and a water temperature sensor 34 for detecting the engine cooling water temperature is provided in the cylinder block 12.

  The engine 10 configured as described above is provided with an electronic control unit (ECU) 100 for controlling the operation of the engine 10. The ECU 100 is connected to the engine speed sensor 20, the intake negative pressure sensor 32, and the water temperature sensor 34 together with various sensors for parameters necessary for grasping the operating state as is well known, and the output signal of each sensor. Is input to the ECU 100.

  Here, the ECU 100 includes a CPU, a ROM, a RAM, a backup RAM, an input port, an output port, and the like connected to each other by a bidirectional bus, and an A / D converter (A / D) connected to the input port. It is comprised with the microcomputer provided with. The A / D converter is connected to a sensor that outputs a signal in an analog signal format, such as an intake negative pressure sensor 32, a water temperature sensor 34, and the like via electric wiring, and the output signal of each sensor is converted from the analog signal format. After converting to digital signal format, send to input port. The output port is connected to the fuel injection valve 22, the spark plug 30 and the like via electric wiring, and transmits the control signal to each.

  The ROM includes a fuel injection amount control routine for determining the fuel injection amount, a fuel injection timing control routine for determining the fuel injection timing, an energization control routine for controlling energization to the spark plug 30, and the like. A control routine necessary for controlling the engine 10 is stored. The RAM stores output signals from each sensor, CPU calculation results, and the like. The calculation result is, for example, an engine speed calculated based on an output signal of the engine speed sensor 20. Various data stored in the RAM are rewritten to the latest data every time the engine speed sensor 20 outputs a signal. Note that the backup RAM is a non-volatile memory that retains data even after the operation of the engine 10 is stopped, and stores learning values related to various controls, information for specifying a location where an abnormality has occurred, and the like. The CPU operates in accordance with an application program stored in the ROM, and executes control of the fuel injection mode that is the gist of the present invention in addition to well-known control of the fuel injection amount and the like.

  Therefore, one form of control in the engine 10 of the present embodiment will be described with reference to FIG. In the control mode shown in FIG. 3, when control is started, it is determined in step S31 whether or not the engine cooling water temperature detected by the water temperature sensor 34, that is, the engine temperature is equal to or lower than a predetermined value T1. As a result of the determination, if NO, that is, higher than the predetermined value T1, the process proceeds to step S32, and normal continuous fuel injection is performed. In this continuous fuel injection, an amount of fuel corresponding to the operating state of the engine is continuously injected from the fuel injection valve 22 toward the spark plug 30, and the spray mixed with air starts injection as shown in FIG. Are ignited and burned continuously by the spark plug 30 started to ignite at substantially the same time.

  On the other hand, if the result of determination in step S31 is YES, that is, if the engine temperature is equal to or lower than the predetermined value T1, the routine proceeds to step S33, where multiple fuel injection is performed by the injection mode control means. In this multiple fuel injection, fuel injection from the fuel injection valve 22 is intermittently performed at regular intervals as shown in FIG. In the case of this multiple fuel injection, the ignition plug 30 is also ignited almost continuously with the start of the first injection, and is continuously ignited. Accordingly, the temperature of the spark plug 30 is appropriately maintained, and good ignition or ignition and continuous combustion are realized.

  Another form of control in the engine 10 of the present embodiment will be described with reference to FIG. In the control mode shown in FIG. 6, as in the above mode, when the control is started, it is determined in step S61 whether or not the engine cooling water temperature detected by the water temperature sensor 34 and the engine temperature is equal to or lower than a predetermined value T1. Is done. If the result of this determination is NO, that is, it is higher than the predetermined value T1, the routine proceeds to step S62, where normal continuous fuel injection is performed. In this continuous fuel injection, an amount of fuel corresponding to the operating state of the engine is continuously injected from the fuel injection valve 22 toward the spark plug 30, and the spray mixed with air is injected as shown in FIG. It is ignited and burned continuously by the spark plug 30 started to ignite at about the same time as the start.

  On the other hand, if the result of determination in step S61 is YES, that is, if the engine temperature is equal to or lower than the predetermined value T1, the routine proceeds to step S63, where pilot injection and main injection are performed by the injection mode control means. In the pilot injection and the main injection, as shown in FIG. 7, the ignition plug 30 is also started to be ignited at about the same time as the start of a small amount of pilot injection and continuously ignited. Thereafter, main fuel injection is performed for a predetermined period from the pilot injection toward the spark plug 30 that is continuously ignited. Accordingly, the temperature of the spark plug 30 is appropriately maintained, and good ignition or ignition and continuous combustion are realized. The main fuel injection described here is continuous injection, but may be multiple fuel injection as described above as long as a required amount of fuel is secured.

  Furthermore, still another form of control in the engine 10 of the present embodiment will be described with reference to FIG. The control mode shown in FIG. 8 is an example in which the fuel injection mode is changed in accordance with the engine load level with respect to the above mode. Therefore, when the control is started, it is determined in step S81 whether or not the engine cooling water temperature detected by the water temperature sensor 34, that is, the engine temperature is equal to or lower than a predetermined value T1. As a result of the determination, if NO, that is, if it is higher than the predetermined value T1, the routine proceeds to step S82, and normal continuous fuel injection is performed. In this continuous fuel injection, an amount of fuel corresponding to the operating state of the engine is continuously injected from the fuel injection valve 22 toward the spark plug 30, and the spray mixed with air is injected as shown in FIG. It is ignited and burned continuously by the spark plug 30 started to ignite at about the same time as the start.

  On the other hand, if the result of determination in step S81 is YES, that is, if the engine temperature is less than or equal to a predetermined value T1, the process proceeds to step S83, whether or not the intake pipe internal pressure detected by the intake negative pressure sensor 32 is greater than or equal to a predetermined value P1 It is then determined whether the engine load is equal to or greater than a predetermined value. As a result of the determination, when NO, that is, smaller than the predetermined value P1, that is, when the load is low, the routine proceeds to step S82, and the normal continuous fuel injection already described is performed. By the way, if the result of determination in step S83 is YES, that is, if the intake pipe internal pressure is a high load equal to or greater than the predetermined value P1, the routine proceeds to step S84, where multiple fuel injection or pilot injection and main injection are performed by the injection mode control means. Is called. In this way, when the engine is under heavy load, if the fuel injection is changed from continuous injection to multiple fuel injection or pilot injection and main injection, the amount of fuel increases corresponding to the load, but ignition is caused by the increased fuel. The temperature is appropriately maintained without excessive cooling of the plug 30, and good ignition or ignition and continuous combustion are realized.

  In the above-described embodiment, the example in which the spark plug that is continuously ignited is used as the ignition source has been described. However, a glow plug may be used instead of the spark plug. Furthermore, in the above-described embodiment, an engine using gasoline as fuel has been described. However, the form of fuel is not limited to this, and other fuels such as light oil and methanol can be used, and their octane number and cetane number can be used. Regardless, knock-free combustion is possible.

It is principal part sectional drawing which shows one Embodiment of the cylinder direct injection continuous combustion engine to which this invention is applied. FIG. 2 is a bottom view seen from the cylinder head combustion chamber surface side of the engine of FIG. It is a flowchart which shows one form of control of embodiment of this invention. It is a time chart which shows the relationship between the continuous fuel injection and continuous ignition in embodiment of this invention. It is a time chart which shows the relationship between the multiple fuel injection and continuous ignition in embodiment of this invention. It is a flowchart which shows the other form of control of embodiment of this invention. It is a time chart which shows the relationship between the pilot, main fuel injection, and continuous ignition in embodiment of this invention. It is a flowchart which shows the further another form of control of embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Engine 22 Fuel injection valve 30 Spark plug 32 Intake negative pressure sensor 34 Water temperature sensor

Claims (3)

In the in-cylinder direct injection continuous combustion engine in which the fuel is continuously injected from the fuel injection valve toward the ignition source in the combustion chamber in the compression stroke, and the spray is continuously ignited and burned,
An engine temperature detecting means for detecting the engine temperature is provided,
An injection mode control means for causing the fuel injection from the fuel injection valve to be in the form of multiple fuel injection or pilot injection and main injection when the engine temperature is below a predetermined value based on the detection result by the engine temperature detection means; An in-cylinder direct injection continuous combustion engine characterized by being provided. In the in-cylinder direct injection continuous combustion engine in which the fuel is continuously injected from the fuel injection valve toward the ignition source in the combustion chamber in the compression stroke, and the spray is continuously ignited and burned,
An engine temperature detecting means for detecting the engine temperature and an engine load detecting means for detecting the engine load;
Based on the detection results by the engine temperature detection means and the engine load detection means, when the engine temperature is equal to or lower than a predetermined value and the engine load is higher than a predetermined value, fuel injection from the fuel injection valve is performed as multiple fuel injection or pilot injection. An in-cylinder direct injection continuous combustion engine, characterized in that it is provided with injection form control means configured to form main injection. The in-cylinder direct injection continuous combustion engine according to claim 2, wherein the main injection is multiple fuel injection.

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