JP2010048194A - Start control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress HC emissions by promoting vaporization or atomization of fuel in especially a first start cycle when starting an internal combustion engine. <P>SOLUTION: In at least the first cycle in starting, the closing timing (EVC) of an exhaust valve is set to the advanced side of an intake top dead center and a crank angle from the closing timing (EVC) of the exhaust valve to the intake top dead center is controlled to be larger than a crank angle between the opening timing (IVO) of an intake valve and the intake top dead center. In at least the first cycle in starting, the fuel injection timing of a fuel injection valve is so controlled that the fuel injection timing overlaps with the opening timing (IVO) of the intake valve. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a start control device for an internal combustion engine, and more particularly to a start control device for a port injection internal combustion engine that injects fuel into an intake port.

For example, a system described in Japanese Patent Application Laid-Open No. 2007-40150 is known as a technique for suppressing HC emission at the time of starting an internal combustion engine. In the system described in this publication, in the first start cycle in which no combustion gas is present in the combustion chamber, so-called intake asynchronous injection is performed so that the fuel evaporating time in the intake port is long, thereby vaporizing the fuel. Promotes. In the second and subsequent cycles in which combustion gas exists in the combustion chamber, the closing timing of the exhaust valve is controlled to be advanced from the intake top dead center, and the fuel injection timing is set in accordance with the opening timing of the intake valve. Thus, the vaporization of the fuel is promoted by the high-temperature combustion gas blown back from the combustion chamber to the intake port.
JP 2007-40150 A JP 2002-227630 A JP 2003-120348 A

  However, there is still room for improvement in the technique described in Japanese Patent Application Laid-Open No. 2007-40150. This is because of the first cycle of start-up, and there is a limit to the fuel vaporization promoting effect obtained by securing the vaporization time. In the first start cycle in which no combustion gas exists, the temperature in the intake port is strongly influenced by the environmental temperature. For this reason, when the environmental temperature is low, there is a possibility that the fuel is not sufficiently vaporized only by securing the vaporization time.

  The present invention has been made to solve the above-described problems, and promotes the vaporization or atomization of fuel at the start of the internal combustion engine, particularly in the first cycle of the start, thereby suppressing the emission of HC. It is an object of the present invention to provide a start control device for an internal combustion engine.

In order to achieve the above object, a first invention provides a start control device for an internal combustion engine having a fuel injection valve for injecting fuel into an intake port and an exhaust valve capable of adjusting a closing timing.
At least in the first cycle at the start, the closing timing of the exhaust valve is advanced from the intake top dead center, and the crank angle from the closing timing to the intake top dead center depends on the opening timing of the intake valve and the intake air. Exhaust valve closing timing control means for controlling to be larger than the crank angle between the top dead center and
Fuel injection timing control means for controlling the fuel injection timing of the fuel injection valve so that the fuel injection period overlaps the opening timing of the intake valve at least in the first cycle at the start;
It is characterized by having.

According to a second invention, in the first invention,
The fuel injection timing control means controls the fuel injection timing so that the vicinity of the approximate center of the fuel injection period overlaps with the opening timing of the intake valve.

According to a third invention, in the first or second invention,
The fuel injection timing control means divides the fuel injection period into a plurality of times, one of the divided fuel injection periods overlaps with the opening timing of the intake valve, and the other period is within the closing period of the intake valve. Thus, the fuel injection timing is controlled as described above.

According to a fourth invention, in the third invention,
The fuel injection timing control means is characterized in that after the second cycle at start-up, the fuel injection period overlapping with the opening timing of the intake valve is decreased in accordance with the increase in engine speed.

In order to achieve the above object, a fifth aspect of the invention is an internal combustion engine having a fuel injection valve that injects fuel into an intake port, an exhaust valve that can adjust the closing timing, and an intake valve that can adjust the opening timing. In the engine start control device,
Exhaust valve closing timing control means for controlling the closing timing of the exhaust valve to be at an advance side from the intake top dead center at least in the first cycle at the time of start;
An intake valve opening timing control means for controlling the opening timing of the intake valve at a first cycle at the time of starting so that the pressure of the combustion chamber of the internal combustion engine is higher than the pressure of the intake port;
Fuel injection timing control means for controlling the fuel injection timing of the fuel injection valve so that the fuel injection period overlaps the opening timing of the intake valve at least in the first cycle at the start;
It is characterized by having.

In order to achieve the above object, a sixth aspect of the invention is an internal combustion engine having a fuel injection valve that injects fuel into an intake port, an exhaust valve that can adjust the closing timing, and an intake valve that can adjust the opening timing. In the engine start control device,
Exhaust valve closing timing control means for controlling the closing timing of the exhaust valve to be at an advance side from the intake top dead center at least in the first cycle at the time of start;
An intake valve opening timing control means for controlling the opening timing of the intake valve at least in the first cycle at the time of starting so as to be when the blowback occurs from the combustion chamber to the intake port;
Fuel injection timing control means for controlling the fuel injection timing of the fuel injection valve so that the fuel injection period overlaps the opening timing of the intake valve at least in the first cycle at the start;
It is characterized by having.

According to a seventh invention, in the fifth or sixth invention,
The intake valve opening timing control means is characterized in that the opening timing of the intake valve is retarded from the closing timing of the exhaust valve.

The eighth invention is the fifth or sixth invention, wherein
The intake valve opening timing control means is configured to advance the intake valve from the intake top dead center by a crank angle equal to or smaller than a crank angle from the exhaust valve close timing to the intake top dead center. It is characterized by that.

A ninth invention is the fifth or sixth invention, wherein
The exhaust valve closing timing control means is characterized in that the closing timing of the exhaust valve is set to be within 30 degrees as a crank angle on the advance side from the intake top dead center.

  According to the first aspect of the present invention, in the first cycle of starting, the exhaust valve closing timing is on the advance side of the intake top dead center, and the crank angle from the closing timing to the intake top dead center is Since it is controlled to be larger than the crank angle between the opening timing and the intake top dead center, the cylinder gas pressure at the intake valve opening timing is higher than the cylinder gas pressure at the exhaust valve closing timing. Get higher. Therefore, the in-cylinder gas compressed in the combustion chamber from the closing timing of the exhaust valve to the opening timing of the intake valve is blown back to the intake port together with the opening of the intake valve. Since the fuel injection period of the first cycle of the start is overlapped with the opening timing of the intake valve, the in-cylinder gas blown back to the intake port collides with the fuel spray injected from the fuel injection valve. The fuel spray is agitated by the collision of the in-cylinder gas, so that the fuel vapor is more vaporized or the fuel spray is more atomized.

  According to the second aspect of the invention, since the fuel spray near the center of the fuel injection period has a small particle size and is stable, the effect of promoting vaporization or atomization is achieved by colliding the in-cylinder gas with the fuel spray. Can be enhanced as.

  According to the third aspect of the invention, a part of the fuel can be vaporized or atomized by colliding the in-cylinder gas with the fuel spray, and the remaining fuel is vaporized by securing the vaporization time in the intake port. Can be promoted.

  According to the fourth aspect of the present invention, the fuel injection period that overlaps with the opening timing of the intake valve is shortened in accordance with the blowback time that becomes shorter as the engine speed increases, so that the agitation effect due to the blowback cannot be obtained. Generation of spray can be suppressed.

  According to the fifth aspect of the present invention, in the first cycle of starting, the exhaust valve closing timing is set to an advance side from the intake top dead center, so that the in-cylinder gas is compressed as the piston rises after the exhaust valve is closed. Is done. The pressure in the combustion chamber changes according to the subsequent vertical movement of the piston, but the intake valve is opened when the pressure in the combustion chamber of the internal combustion engine is higher than the pressure in the intake port. For this reason, when the intake valve is opened, the in-cylinder gas compressed in the combustion chamber is blown back to the intake port. Since the fuel injection period of the first cycle of the start is overlapped with the opening timing of the intake valve, the in-cylinder gas blown back to the intake port collides with the fuel spray injected from the fuel injection valve. The fuel spray is agitated by the collision of the in-cylinder gas, so that the fuel vapor is more vaporized or the fuel spray is more atomized.

  According to the sixth aspect of the present invention, in the first cycle of the start, the exhaust valve is closed at the advance side of the intake top dead center so that the in-cylinder gas is compressed as the piston rises after the exhaust valve is closed. Is done. The pressure in the combustion chamber changes according to the subsequent vertical movement of the piston, and the pressure difference between the pressure in the intake port and the pressure in the combustion chamber changes accordingly. The valve is opened. That is, in-cylinder gas is blown back from the combustion chamber to the intake port when the intake valve is opened in the first start cycle. Since the fuel injection period of the first cycle of the start is overlapped with the opening timing of the intake valve, the in-cylinder gas blown back to the intake port collides with the fuel spray injected from the fuel injection valve. The fuel spray is agitated by the collision of the in-cylinder gas, so that the fuel vapor is more vaporized or the fuel spray is more atomized.

  According to the seventh aspect of the present invention, the in-cylinder gas is compressed between the closing timing of the exhaust valve and the opening timing of the intake valve by setting the opening timing of the intake valve to the retard side of the closing timing of the exhaust valve. be able to.

  According to the eighth invention, the opening timing of the intake valve is set to the advance side of the intake top dead center by a crank angle equal to or smaller than the crank angle from the closing timing of the exhaust valve to the intake top dead center. Thus, the pressure of the in-cylinder gas at the opening timing of the intake valve can be reliably made higher than the pressure of the in-cylinder gas at the closing timing of the exhaust valve.

  According to the ninth aspect of the present invention, the in-cylinder gas can be appropriately compressed by setting the closing timing of the exhaust valve within 30 degrees in terms of the crank angle to the advance side from the intake top dead center.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below with reference to FIGS. 1 to 5.

  FIG. 1 is a diagram showing a schematic configuration of an internal combustion engine to which a start control device as Embodiment 1 of the present invention is applied. The internal combustion engine according to this embodiment is a spark ignition type four-stroke engine. The internal combustion engine includes a cylinder block 6 in which a piston 8 is disposed, and a cylinder head 4 assembled to the cylinder block 6. A space from the upper surface of the piston 8 to the cylinder head 4 forms a combustion chamber 10. A spark plug 16 is attached to the top of the combustion chamber 10. The cylinder head 4 is formed with an intake port 36 and an exhaust port 40 that communicate with the combustion chamber 10.

  An intake valve 12 that controls a communication state between the intake port 36 and the combustion chamber 10 is provided at a connection portion between the intake port 36 and the combustion chamber 10. The drive system of the intake valve 12 is provided with an intake valve timing control device 22 that variably controls the opening / closing timing of the intake valve 12 (hereinafter referred to as intake valve timing). In this embodiment, as the intake valve timing control device 22, the hydraulic pressure that can change the opening timing and the closing timing of the intake valve 12 at the same time by changing the phase angle of the cam shaft with respect to the crankshaft 18 while keeping the operating angle constant. A variable valve timing mechanism (VVT) is used. The intake valve timing control device 22 has a lock structure for preventing malfunction when the hydraulic pressure is not sufficiently increased. This lock structure locks the operation of the intake valve timing control device 22 when the hydraulic pressure is low, and automatically releases the lock when the hydraulic pressure rises to a certain level. When the intake valve timing control device 22 is locked by the lock structure, the opening timing of the intake valve 12 is fixed in the vicinity of the intake TDC, more specifically, slightly advanced from the intake TDC.

  On the other hand, an exhaust valve 14 for controlling a communication state between the exhaust port 40 and the combustion chamber 10 is provided at a connection portion between the exhaust port 40 and the combustion chamber 10. The drive system of the exhaust valve 14 is provided with an exhaust valve timing control device 24 that variably controls the opening / closing timing of the exhaust valve 14 (hereinafter referred to as exhaust valve timing). As the exhaust valve timing control device 24, a hydraulic valve timing variable mechanism is used as in the intake valve timing control device 22. When the exhaust valve timing control device 24 is locked by the lock structure, the exhaust valve timing is fixed at the most advanced position.

  An intake pipe 30 is connected to the intake port 36. A throttle 32 is disposed in the intake pipe 30. The intake pipe 30 branches for each cylinder downstream of the throttle 32 and is connected to an intake port 36 of each cylinder. A fuel injection valve 34 that injects fuel into the intake port 36 is attached in the vicinity of the connection portion of the intake pipe 30 with the intake port 36.

  Further, the internal combustion engine according to the present embodiment includes an ECU (Electronic Control Unit) 50 as a control device thereof. In addition to the intake valve timing control device 22, the exhaust valve timing control device 24, the fuel injection valve 34, the throttle 32, and the spark plug 16, various devices such as the starter 20 are connected to the output side of the ECU 50. Various sensors such as a crank angle sensor 52, a water temperature sensor 54, an air flow sensor 56, and various switches such as a start switch 58 are connected to the input side of the ECU 50. The crank angle sensor 52 is a sensor that outputs a signal corresponding to the rotation angle of the crankshaft 18. The water temperature sensor 54 is a sensor that outputs a signal corresponding to the cooling water temperature of the internal combustion engine. The air flow sensor 56 is a sensor that outputs a signal corresponding to the flow rate of air sucked into the intake pipe 30. The start switch 58 is a switch that receives a start request from the driver to the internal combustion engine. The ECU 50 drives each device in accordance with a predetermined control program based on the outputs of these sensors and switches.

  The present embodiment is characterized by the control of the exhaust valve timing at the start and the control of the fuel injection timing among the control of the internal combustion engine executed by the ECU 50. FIG. 2 is a flowchart showing the contents of the exhaust valve timing control executed by the ECU 50 in the present embodiment. The routine shown in FIG. 2 is executed at the same time as the start switch 58 is turned on and cranking of the internal combustion engine is started by the starter 20. This routine is executed for each cylinder.

  According to the routine shown in FIG. 2, the exhaust valve early closing control is performed as the control of the exhaust valve timing at the start (step S2). The exhaust valve early closing control is continued until the water temperature measured by the water temperature sensor 54 reaches the target water temperature (step S4). The target water temperature used in the determination in step S4 is a reference value for determining whether or not the internal combustion engine has been sufficiently warmed through the warm-up operation after starting. When the water temperature reaches the target water temperature, the control of the exhaust valve timing is switched from the exhaust valve early closing control at the start to the exhaust valve normal control (step S6).

  Details of the exhaust valve early closing control and the exhaust valve normal control will be described with reference to FIG. FIG. 3 is a diagram illustrating the opening / closing timings of the intake valve 12 and the exhaust valve 14 for the exhaust valve early closing control and the exhaust valve normal control, respectively. In FIG. 3, EVO represents the opening timing of the exhaust valve 14, EVC represents the closing timing of the exhaust valve 14, and the crank angle from EVO to EVC (shown by a black arc) represents the opening period of the exhaust valve 14. IVO represents the opening timing of the intake valve 12, IVC represents the closing timing of the intake valve 12, and the crank angle (indicated by a white arc) from IVO to IVC represents the opening period of the intake valve 12.

  As shown in FIG. 3, the exhaust valve early closing control is control for setting the closing timing of the exhaust valve 14 to the advance side with respect to the intake TDC and to the advance side with respect to the closing timing of the intake valve 12. . As described above, the exhaust valve timing control device 24 is provided with a lock structure, and the exhaust valve timing is fixed at the most advanced position until the hydraulic pressure increases. Further, due to the lock structure of the intake valve timing control device 22, the intake valve timing is fixed at a position where the opening timing is slightly advanced from the intake TDC. Therefore, at the start of the internal combustion engine, at least for the first cycle of the start, the exhaust valve early closing control is automatically performed due to the structure of the exhaust valve timing control device 24 and the intake valve timing control device 22.

  The exhaust valve normal control is control for setting the exhaust valve timing at an appropriate position on the output performance of the internal combustion engine. In the example shown in FIG. 3, the exhaust valve timing is controlled so that the open period of the exhaust valve 14 and the open period of the intake valve 12 overlap. Such normal exhaust valve control is possible after the lock of the exhaust valve timing control device 24 by the lock structure is released. When the determination in step S4 is satisfied, that is, when the warm-up of the internal combustion engine is completed, the hydraulic pressure is sufficiently increased and the lock of the exhaust valve timing control device 24 by the lock structure is released.

  As described above, in the present embodiment, the exhaust valve timing control at the start refers to the exhaust valve early closing control. In parallel with the exhaust valve early closing control, the fuel injection timing control at the start is performed. FIG. 4 is a diagram for explaining the contents of the fuel injection timing control at the time of start executed in the present embodiment. FIG. 4 shows changes in the exhaust valve timing and intake valve timing by the exhaust valve early closing control, and the flow velocity of the intake valve portion (the connection portion between the intake port 36 and the combustion chamber 10) realized by the exhaust valve early closing control. Is also shown.

  As shown in FIG. 4, during the exhaust valve early closing control, the exhaust valve 14 is closed before the intake TDC, and the intake valve 12 is opened near the intake TDC. As a result, the gas in the combustion chamber 10 (hereinafter referred to as in-cylinder gas) is compressed by the piston 8 during the period from the closing timing of the exhaust valve 14 to the opening timing of the intake valve 12 to become high temperature and high pressure, and the intake valve 12 is opened. At the same time, the air is blown back to the intake port 36. This blowback occurs when the pressure in the combustion chamber 10 of the internal combustion engine is higher than the pressure in the intake port 36, and generates a high-speed gas flow from the combustion chamber 10 toward the intake port 36. The gas blown back to the intake port 36 is again sucked into the combustion chamber 10 from the intake port 36 as the piston 8 descends. In FIG. 4, the flow rate of gas from the intake port 36 toward the combustion chamber 10 is indicated by +, and the flow rate of gas from the combustion chamber 10 toward the intake port 36 is indicated by −. During normal control of the exhaust valve, there is a period in which both the exhaust valve 14 and the intake valve 12 are open near the intake TDC. During this period, the pressure in the intake port 36 and the pressure in the combustion chamber 10 are substantially the same, so that the in-cylinder gas is blown back to the intake port 36 little or substantially.

  The fuel injection period shown in FIG. 4 is a fuel injection period by fuel injection timing control at the time of starting. In the present embodiment, the fuel injection timing is controlled so that the vicinity of the approximate center of the fuel injection period overlaps the opening timing of the intake valve 12. In other words, the fuel injection is started before the opening timing of the intake valve 12 (advanced side), and the fuel is continuously injected at the opening timing of the intake valve 12, and after the opening timing of the intake valve 12. The fuel injection ends on the retarded side. According to this, the high-speed in-cylinder gas blown back from the combustion chamber 10 to the intake port 36 when the intake valve 12 is opened can collide with the fuel spray injected from the fuel injection valve 34. The fuel spray is agitated by the collision of the in-cylinder gas, and becomes a vaporized fuel vapor or a more atomized fuel spray.

  Further, the fuel injection timing control at the start is continuously performed from the first cycle until the exhaust valve early closing control is switched to the exhaust valve normal control. In this case, the in-cylinder gas blown back differs between the first start cycle and the second and subsequent cycles. From the second cycle onward, high-temperature and high-pressure combustion gas obtained by fuel combustion is blown back. On the other hand, in the first start cycle, the air compressed to high temperature and high pressure by the piston 8 is blown back. The air blown back at the first start cycle is not as hot as the combustion gas blown back after the second start cycle. However, the fuel spray agitation effect by the collision of the blown-in cylinder gas can be obtained equally. By being agitated by blow-back, the fuel spray becomes fuel vapor that has been further vaporized or fuel spray that has been further atomized. Therefore, according to the start control according to the present embodiment, it is possible to promote fuel vaporization or atomization from the first start cycle, thereby suppressing the discharge of HC at the start.

  The reason why the vicinity of the center of the fuel injection period overlaps with the opening timing of the intake valve 12 rather than immediately after the start or the end of the fuel injection period is to promote the vaporization or atomization of fuel spray due to the collision of the in-cylinder gas. This is to bring out the maximum. FIG. 5 is a graph showing changes in the particle size of the fuel spray within the fuel injection period. The fuel injected immediately after the start of injection collides with the air having no movement at the tip of the fuel injection valve 34, and becomes a spray with a large particle size and hardly vaporized. In addition, since the fuel injection pressure decreases in the latter half of the injection, the spray particle sizes become uneven. On the other hand, the fuel spray injected near the center of the fuel injection period has a small particle size and is stable. By making the in-cylinder gas collide with the stable fuel spray having a small particle size, the effect of promoting vaporization or atomization can be enhanced as a whole.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described with reference to FIGS. 1 and 6 to 8.

  The start control device as the second embodiment of the present invention is applied to the internal combustion engine having the configuration shown in FIG. 1 as in the first embodiment. Therefore, in the following description, it is assumed that the configuration shown in FIG.

  The difference between the present embodiment and the first embodiment is in the fuel injection control at the time of start executed by the ECU 50. The exhaust valve timing control at the start is the same as that in the first embodiment. FIG. 6 is a flowchart showing the contents of the fuel injection control at the time of start executed by the ECU 50 in the present embodiment. The routine shown in FIG. 6 is started at the same time when the start switch 58 is turned on and cranking of the internal combustion engine is started by the starter 20. This routine is executed for each cylinder.

  In the first step S100 of this routine, it is determined whether or not this time is the first start cycle. If this time is the first cycle of starting, fuel injection control is performed by the processing after step S102, and if this time is after the second starting cycle, fuel injection control is performed by processing after step S114. That is, in the present embodiment, there is a difference in the content of the fuel injection control between the first start cycle and the second and subsequent start cycles.

  If this is the first start cycle, first, the starting water temperature (thws) measured by the water temperature sensor 54 in step S102 is captured. In the next step S104, the starting injection amount (tausta) is obtained from the map based on the starting water temperature (thws). In step S106, the starting injection amount (tausta) is set as the final injection amount (TAU). The final injection amount (TAU) is converted into a fuel injection period.

  In step S108, it is determined whether the starting water temperature (thws) is lower than the reference temperature (α). The reference temperature (α) is a water temperature at which sufficient vaporization of the injected fuel in the intake port 36 can be expected. The situation where the water temperature (thws) at the start is higher than the reference temperature (α) is, for example, when restarting from an idling stop. If the starting water temperature (thws) is higher than the reference temperature (α), the process proceeds to step S112, and normal fuel injection timing control is performed. The normal fuel injection timing control is fuel injection timing control in a situation where a special vaporization or atomization promoting effect is not required. Specifically, intake asynchronous injection control or intake synchronous injection control is used. In the intake asynchronous injection control, fuel is injected within a period during which the intake valve 12 is closed. In the intake synchronous injection control, fuel is injected when the intake valve 12 is open.

  When the starting water temperature (thws) is lower than the reference temperature (α), the process of step S110 is performed. In step S110, the fuel injection timing is controlled so that the fuel injection period overlaps the opening timing of the intake valve 12. Since the opening timing of the intake valve 12 is in the vicinity of the intake TDC, the fuel injection at this time is hereinafter referred to as intake TDC injection control. As described in the first embodiment, according to the intake TDC injection control, the fuel spray can be stirred by the collision of the blown-in cylinder gas, and the vaporization or atomization of the fuel spray is promoted by the stirring effect. Can do.

  If it is determined in step S100 that this is the second start cycle, first, in step S114, the fuel injection amount increase correction rate (fwl) corresponding to the starting water temperature (thws) is obtained. FIG. 7 is a diagram showing an image of a map for obtaining the increase correction rate (fwl) from the starting water temperature (thws). As the starting water temperature (thws) is lower, the increasing correction factor (fwl) is set larger. When the starting water temperature (thws) is higher than a certain temperature, the increasing correction factor (fwl) is set to zero.

  In the next step S116, the basic fuel injection amount (tau) is calculated. For calculation of the basic injection amount (tau), the intake air amount (Ga) calculated from the signal from the air flow sensor 56 and the engine speed (NE) calculated from the signal from the crank angle sensor 52 are used.

In step S118, the final injection amount (TAU) is calculated by the following equation using the basic injection amount (tau) calculated in step S116 and the increase correction factor (fwl) calculated in step S114. In the following equation, fwlk is an attenuation coefficient for attenuating the increase correction factor (fwl). The initial value of Fwlk is set to 1, and the value decreases every rotation.
TAU = tau x (1 + fwl x fwlk)

  In the next step S120, a reference value used in the determination described later is calculated. The determination is a determination for switching the fuel injection timing, and whether or not the integrated value (hereinafter referred to as integrated Ga) from the start of the intake air amount is larger than the integrated Ga (gaft) serving as a switching reference. Determined. FIG. 8 is a diagram showing an image of a map for obtaining the switching reference integrated Ga (gaft) from the starting water temperature (thws). The lower the starting water temperature (thws), the larger the switching reference integrated Ga (gaft) is set. If the starting water temperature (thws) is equal to or higher than a certain temperature, the switching reference integrated Ga (gaft) is set to zero.

  In step S122, the integrated Ga (gat) value from the start is updated based on a signal acquired from the airflow sensor 56 between the previous time and the current time. Then, in the next step 124, it is determined whether or not the accumulated Ga (gat) calculated up to the present in step S122 exceeds the switching reference accumulated Ga (gaft) calculated in step S120.

  As a result of the determination in step S124, when the accumulated Ga (gat) up to the present does not exceed the switching reference accumulated Ga (gaft), the process proceeds to step S110, and intake TDC injection control is performed as in the first cycle of start. That is, the fuel injection timing is controlled so that the fuel injection period overlaps with the opening timing of the intake valve 12 until the integrated Ga (gat) exceeds the switching reference integrated Ga (gaft) after the second cycle of starting. Thereby, the high-temperature combustion gas blown back from the inside of the combustion chamber 10 can collide with the fuel spray, and vaporization or atomization of the fuel spray can be promoted by the heat of the combustion gas and the stirring effect due to the collision.

  When the accumulated Ga (gat) up to the present exceeds the switching reference accumulated Ga (gaft), the process proceeds to step S126. By selecting step S126, the control of the fuel injection timing is switched from the intake TDC injection control to the intake asynchronous injection control. In addition, when the starting water temperature (thws) is high and the switching reference integrated Ga (gaft) is set to zero, intake asynchronous injection control is performed from the second start cycle.

Embodiment 3 FIG.
Next, Embodiment 3 of the present invention will be described with reference to FIG. 1 and FIG.

  The start control device as the third embodiment of the present invention is applied to the internal combustion engine having the configuration shown in FIG. 1 as in the first embodiment. Therefore, in the following description, it is assumed that the configuration shown in FIG.

  This embodiment is characterized by the fuel injection control at the time of start executed by the ECU 50. The start-up fuel injection control according to the present embodiment is based on the start-up fuel injection control according to the second embodiment. FIG. 9 is a flowchart showing the contents of the fuel injection control at the time of start executed by the ECU 50 in the present embodiment. Among the processes shown in the flowchart of FIG. 9, processes that are the same as those in the second embodiment are denoted by the same step numbers as those in the second embodiment. In the following, description of processes common to the second embodiment will be omitted or simplified, and processes different from those of the second embodiment will be mainly described.

  The feature of the routine shown in FIG. 9 is in the processing when it is determined in step S108 that the water temperature (thws) at start-up is lower than the reference temperature (α). According to this routine, the process of step S200 is performed instead of the process of step S110 according to the second embodiment.

  In step S200, control is performed in which the final injection amount (TAU) calculated in step S106 is divided into multiple injections (hereinafter referred to as multiple injection control). Here, the final injection amount (TAU) is divided into 1: 3, and a quarter of the final injection amount (TAU) is injected by the intake TDC injection control. Then, the final injection amount (TAU) 3/4 is injected by the intake asynchronous injection control prior to the intake TDC injection control. The injection end timing of the intake asynchronous injection control is set to a timing (for example, 90 ° BTDC) such that the fuel injection period does not overlap with the fuel injection period of the intake TDC injection control.

  As described above, in the start control according to the present embodiment, at least for the first cycle of start, the intake TDC injection control and the intake asynchronous injection control are used together as the fuel injection timing control. According to this, the following effects can be obtained as compared with the case where only intake TDC injection control is used.

  According to the intake TDC injection control, the in-cylinder gas blown back from the combustion chamber 10 can collide with the fuel spray. However, as shown in FIG. 4, the in-cylinder gas blow-back time is shorter than the fuel injection period. For this reason, not all fuel sprays can obtain a stirring effect by blowing back. Therefore, in the present embodiment, intake TDC injection control is performed for an amount of fuel that can provide a stirring effect by blowback, and the remaining fuel is injected early by intake asynchronous injection control. By injecting the fuel that cannot be agitated by blowing back at an early stage, it is possible to secure the atomization time in the intake port and the time in which the fuel that has not been atomized accumulates near the intake valve 12 by its own weight. The fuel accumulated in the vicinity of the intake valve 12 is blown back to the upstream side of the intake port 36 by the blow back when the intake valve 12 is opened, and the vaporization or atomization is promoted. Therefore, according to the start control according to the present embodiment, it is possible to promote vaporization or atomization of the entire injected fuel, thereby suppressing HC emission at the start.

  In the routine shown in FIG. 9, the blow ratio of intake TDC injection control and intake asynchronous injection control is set to 1: 3, but this is only an example. The blowing ratio can be set as appropriate, such as 1: 4.

Embodiment 4 FIG.
Next, a fourth embodiment of the present invention will be described with reference to FIG. 1, FIG. 10, and FIG.

  The start control device as the fourth embodiment of the present invention is applied to the internal combustion engine having the configuration shown in FIG. 1 as in the first embodiment. Therefore, in the following description, it is assumed that the configuration shown in FIG.

  This embodiment is characterized by the fuel injection control at the time of start executed by the ECU 50. The start-up fuel injection control according to the present embodiment is based on the start-up fuel injection control according to the third embodiment. FIG. 10 is a flowchart showing the content of the fuel injection control at the time of start executed by the ECU 50 in the present embodiment. Of the processes shown in the flowchart of FIG. 10, processes that are the same as those in the third embodiment are denoted by the same step numbers as those in the third embodiment. In the following, description of processes common to the third embodiment is omitted or simplified, and processes different from those of the third embodiment are mainly described.

  The feature of the routine shown in FIG. 10 resides in the processing after the second start cycle. According to this routine, if it is determined in step S124 that the accumulated Ga (gat) up to the present time does not exceed the switching reference accumulated Ga (gaft), the process replaces the process of step S200 according to the third embodiment. Subsequent processing is performed.

  First, in step S300, an upper limit fuel injection amount (hereinafter referred to as intake TDC injection amount) (tautdc) by intake TDC injection control is determined based on the current engine speed (NE). The intake TDC injection amount (tautdc) is an upper limit value of the fuel injection amount at which an agitation effect by blowing back is obtained. FIG. 11 is a diagram showing a map image for obtaining the intake TDC injection amount (tautdc) from the engine speed (NE). In this map, the intake TDC injection amount (tautdc) decreases as the engine speed (NE) increases. This is because after the second cycle of start-up, the blow-back time becomes shorter as the engine speed (NE) increases, and accordingly, the intake TDC injection amount (tautdc) is reduced accordingly.

  In the next step S302, it is determined whether or not the final injection amount (TAU) calculated in step S118 is greater than or equal to the intake TDC injection amount (tautdc) obtained in step S300. When the final injection amount (TAU) is equal to or greater than the intake TDC injection amount (tautdc), some fuel cannot be injected by the intake TDC injection control. In this case, the process proceeds to step S306, and multiple-injection control is performed in which fuel is injected separately into intake TDC injection control and intake asynchronous injection control. Specifically, prior to the intake TDC injection control, the difference fuel between the final injection amount (TAU) and the intake TDC injection amount (tautdc) is injected by the intake asynchronous injection control. Then, the fuel corresponding to the intake TDC injection amount (tautdc) is injected by the intake TDC injection control. The injection end timing of the intake asynchronous injection control is set to a timing (for example, 90 ° BTDC) such that the fuel injection period does not overlap with the fuel injection period of the intake TDC injection control.

  On the other hand, when the final injection amount (TAU) is smaller than the intake TDC injection amount (tautdc), all the fuel can be injected by the intake TDC injection control. In that case, first, the process of step S304 is performed. In step S304, the value of the intake TDC injection amount (tautdc) is replaced with the final injection amount (TAU). Thereafter, the process of step S306 is performed. The difference between the final injection amount (TAU) and the intake TDC injection amount (tautdc) is eliminated by the processing in step S304, and the fuel injected by the intake asynchronous injection control becomes zero. Then, all the fuel corresponding to the final injection amount (TAU) is injected by the intake TDC injection control.

  As described above, in the start control according to the present embodiment, after the second start cycle in which the engine speed increases, fuel injection by the intake TDC injection control is performed in accordance with the blowback time that becomes shorter as the engine speed increases. The amount is also reduced. According to this, generation | occurrence | production of the fuel spray which cannot obtain the stirring effect by blowback can be suppressed. Further, the amount of fuel reduced in the intake TDC injection control can ensure an atomization time or the like by early injection by the intake asynchronous injection control. Therefore, according to the start control according to the present embodiment, it is possible to further promote the vaporization or atomization of the injected fuel as a whole after the second start cycle.

Embodiment 5 FIG.
Next, a fifth embodiment of the present invention will be described with reference to FIGS.

  The start control device as the fifth embodiment of the present invention is applied to the internal combustion engine having the configuration shown in FIG. 1 as in the first embodiment. Therefore, in the following description, it is assumed that the configuration shown in FIG.

  This embodiment is characterized by the fuel injection control at the time of start executed by the ECU 50. The start-up fuel injection control according to the present embodiment is based on the start-up fuel injection control according to the fourth embodiment. FIG. 12 is a flowchart showing the contents of fuel injection control at the time of start executed by the ECU 50 in the present embodiment. Of the processes shown in the flowchart of FIG. 12, processes that are the same as those in the fourth embodiment are given the same step numbers as those in the fourth embodiment. In the following, description of processes common to the fourth embodiment is omitted or simplified, and processes different from those of the fourth embodiment are mainly described.

  The routine shown in FIG. 12 is characterized in that the upper limit fuel injection amount of the intake TDC injection control to be performed after the second cycle of the start is set to an amount corresponding to a predetermined crank angle range centered on IVO. The predetermined crank angle range is a range in which an agitation effect by blow-back can be reliably obtained. According to this routine, when it is determined in step S124 that the accumulated Ga (gat) up to the present does not exceed the switching reference accumulated Ga (gaft), step S400 is substituted for the process of step S300 according to the fourth embodiment. And the process of S402 is performed.

  In step S400, the amount of fuel that can be injected in the range of 60 ° crank angle centered on IVO (hereinafter, 60 ° CA injection amount) (tauca) is determined based on the current engine speed (NE). The 60 ° CA injection amount (tauca) decreases as the engine speed (NE) increases. In the next step S402, the 60 ° CA injection amount (tauca) obtained in step S400 is set as the intake TDC injection amount (tautdc).

  After the determination of the next step S302, according to this routine, the process of step S404 is performed instead of the process of step S306 according to the fourth embodiment. In step S404, multiple injection control is performed in which fuel is injected separately into intake TDC injection control and intake asynchronous injection control. However, when the final injection amount (TAU) is smaller than the intake TDC injection amount (tautdc) and the process of step S304 is performed, all the fuel is injected by the intake TDC injection control.

  The intake TDC injection control performed in step S404 is characterized in that the fuel injection period is set based on the end timing of fuel injection. There is no such limitation on the intake TDC injection control executed in step S200 or step S306 according to the third embodiment. Regarding these, the fuel injection period by the intake TDC injection control may be set based on the start timing of the fuel injection. In step S404, the end timing of fuel injection by the intake TDC injection control is 30 ° after the IVO.

  As described above, in the start control according to the present embodiment, intake TDC injection is performed with the 30 ° crank angle after IVO as the injection end timing so that the fuel injection period falls within the range of the 60 ° crank angle centered on IVO. Control is performed. According to this, generation | occurrence | production of the fuel spray which cannot obtain the stirring effect by blowback can be prevented more effectively.

  In the routine shown in FIG. 12, the intake TDC injection amount (tautdc) is an injection amount corresponding to the range of 60 ° crank angle centered on IVO, but the 60 ° crank angle centered on IVO is merely an example. Only. The crank angle range may be set as appropriate according to the positional relationship between the fuel injection valve 34 and the intake valve 12 and the structure of the intake port 36. Further, the crank angle before IVO and the crank angle after IVO may be set differently instead of centering on IVO.

Embodiment 6 FIG.
Next, a sixth embodiment of the present invention will be described with reference to FIGS.

  The start control device as the sixth embodiment of the present invention is applied to the internal combustion engine having the configuration shown in FIG. 1 as in the first embodiment. Therefore, in the following description, it is assumed that the configuration shown in FIG.

  This embodiment is characterized by the fuel injection control at the time of start executed by the ECU 50. The start-up fuel injection control according to the present embodiment is based on the start-up fuel injection control according to the fifth embodiment. FIG. 13 is a flowchart showing the content of the fuel injection control at the time of start executed by the ECU 50 in the present embodiment. Of the processes shown in the flowchart of FIG. 13, processes that are the same as those in the fifth embodiment are denoted by the same step numbers as those in the fifth embodiment. In the following, description of processes common to the fifth embodiment is omitted or simplified, and processes different from those of the fifth embodiment are mainly described.

  The feature of the routine shown in FIG. 13 is that the content of the intake TDC injection control executed after the second cycle of the start is made different depending on whether or not the final injection amount (TAU) is equal to or larger than the intake TDC injection amount (tautdc). According to this routine, when it is determined in step S302 that the final injection amount (TAU) is greater than or equal to the intake TDC injection amount (tautdc), the process of step S404 is performed as in the fifth embodiment. On the other hand, when it is determined that the final injection amount (TAU) is smaller than the intake TDC injection amount (tautdc), the process of step S500 is performed instead of step S404 after the process of step S304.

  The intake TDC injection control performed in step S500 is characterized in that the fuel injection period is set based on the fuel injection start timing, not the fuel injection end timing. In step S500, the start timing of fuel injection by the intake TDC injection control is set to 30 ° crank angle before IVO.

  As described above, in the start control according to the present embodiment, when the final injection amount (TAU) falls within the intake TDC injection amount (tautdc), fuel injection is started from the 30 ° crank angle before the IVO. According to this, the collision ratio between blow-back and fuel spray can be maximized, and the fuel spray agitation effect due to the collision can be further enhanced.

Embodiment 7 FIG.
Next, a seventh embodiment of the present invention will be described with reference to FIG. 1, FIG. 14 and FIG.

  The start control device as the seventh embodiment of the present invention is applied to the internal combustion engine having the configuration shown in FIG. 1 as in the first embodiment. Therefore, in the following description, it is assumed that the configuration shown in FIG.

  The present embodiment is characterized by the opening timing of the intake valve 12 in the first start cycle. The closing timing of the exhaust valve 14 in the first start cycle is on the more advanced side than the intake TDC, as in the first embodiment. More specifically, in the present embodiment, the closing timing of the exhaust valve 14 is set to 30 ° on the advance side with respect to the intake TDC. Considering the balance between the compression effect of the in-cylinder gas due to the early closing of the exhaust valve 14 and the cranking load due to the compression work, the closing timing of the exhaust valve 14 is preferably about 30 °.

  When the closing timing of the exhaust valve 14 is determined as described above, as shown in FIG. 14, the opening timing of the intake valve 12 is retarded from the intake TDC from about 30 ° (30 ° BTDC) to the advance side of the intake TDC. By setting the pressure within the range of about 30 ° (30 ° ATDC) to the side, the pressure of the in-cylinder gas at the opening timing of the intake valve 12 can be made higher than the pressure of the in-cylinder gas at the closing timing of the exhaust valve 14. . That is, blowback to the intake port 36 can be generated. Therefore, if the opening timing of the intake valve 12 is determined within the range shown in FIG. 14 and fuel injection is performed at the opening timing, the fuel spray collides with the in-cylinder gas blown back. The fuel spray is agitated by the collision of the in-cylinder gas, so that the fuel vapor is more vaporized or the fuel spray is more atomized.

  FIG. 15 is a diagram showing opening / closing timings of the intake valve and the exhaust valve during the exhaust valve early closing control according to the present embodiment. As shown in FIG. 15, in the present embodiment, at least the opening timing of the intake valve 12 in the first start cycle is set in the vicinity of the intake TDC. The closer the opening timing of the intake valve 12 is to the intake TDC, the larger the pressure difference between the pressure of the cylinder gas at the opening timing of the intake valve 12 and the pressure of the cylinder gas at the closing timing of the exhaust valve 14 can be increased. Therefore, according to the present embodiment, it is possible to increase the flow rate of blowback of the in-cylinder gas that is generated when the intake valve 12 is opened, and thus it is possible to enhance the fuel spray agitation effect due to the blowback of the cylinder gas. .

Embodiment 8 FIG.
Next, an eighth embodiment of the present invention will be described with reference to FIGS.

  The start control device as the eighth embodiment of the present invention is applied to the internal combustion engine having the configuration shown in FIG. 1 as in the first embodiment. Therefore, in the following description, it is assumed that the configuration shown in FIG.

  In the present embodiment, the opening timing of the intake valve 12 in the first start cycle can be controlled according to, for example, operating conditions. In the present embodiment, as the intake valve timing control device 22, an electromagnetic valve mechanism that drives the intake valve 12 with a solenoid or a motor-driven valve mechanism that rotates a cam with an electric motor is used. Yes. What is common to these valve operating mechanisms is that the intake valve 12 can be opened instantaneously by a valve opening signal.

  As described in the seventh embodiment, when the crank angle from the closing timing of the exhaust valve 14 to the intake TDC is larger than the crank angle between the opening timing of the intake valve 12 and the intake TDC, the intake air When the valve 12 is opened, blowback from the combustion chamber 10 to the intake port 36 can surely occur. However, if blowback occurs, the crank angle from the closing timing of the exhaust valve 14 to the intake TDC is smaller than the crank angle between the opening timing of the intake valve 12 and the intake TDC, as shown in FIG. May be. For example, when the internal energy of the in-cylinder gas increases due to heat applied from the outside between the closing timing of the exhaust valve 14 and the opening timing of the intake valve 12, the opening timing of the intake valve 12 as shown in FIG. Blowback can occur.

  The condition that blowback from the combustion chamber 10 to the intake port 36 is that the pressure of the combustion chamber 10 is higher than the pressure of the intake port 36. Therefore, the ECU 50 according to the present embodiment measures the pressure of the intake port 36 with an intake pipe pressure sensor (not shown) and determines the pressure in the combustion chamber 10 to determine whether or not the above condition is satisfied. Measured by an in-cylinder pressure sensor (not shown). Then, before the pressure in the combustion chamber 10 becomes lower than the pressure in the intake port 36, the intake valve timing control device 22 is operated to open the intake valve 12.

  In the first cycle at the time of starting, the throttle 32 is fully opened, so that the pressure of the intake port 36 is substantially equal to the atmospheric pressure. Therefore, instead of the output value of the intake pipe pressure sensor, the output value of the atmospheric pressure sensor may be compared with the output value of the in-cylinder pressure sensor.

Others.
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, the following modifications may be made.

  In the first embodiment, the vicinity of the approximate center of the fuel injection period overlaps the opening timing of the intake valve 12, but this denies that the opening timing of the intake valve 12 deviates from the center of the fuel injection period. It is not a thing. If at least a part from immediately after the start of the fuel injection period to just before the end overlaps the opening timing of the intake valve 12, the effect of promoting vaporization or atomization of the fuel spray due to the collision of the in-cylinder gas occurs.

  In each of the third to sixth embodiments, the fuel injection timing control in step S200 that is performed in the first cycle of starting may vary the blow ratio between the intake TDC injection control and the intake asynchronous injection control. it can. For example, the blowing ratio may be changed according to the starting water temperature (thws).

1 is a schematic configuration diagram of an internal combustion engine to which a start control device as Embodiment 1 of the present invention is applied. It is a flowchart which shows the routine of the exhaust valve timing control performed in Embodiment 1 of this invention. It is a figure which shows the opening / closing timing of the intake valve and exhaust valve concerning Embodiment 1 of this invention about each at the time of exhaust valve early closing control, and at the time of exhaust valve normal control. It is a figure for demonstrating the fuel-injection timing control at the time of starting performed in Embodiment 1 of this invention. It is a figure which shows the change of the particle size of the fuel spray within a fuel-injection period. It is a flowchart which shows the routine of the fuel injection timing control at the time of the starting performed in Embodiment 2 of this invention. It is a figure which shows the setting of the increase correction factor (fwl) of the fuel injection quantity with respect to the water temperature (thws) at the time of starting. It is a figure which shows the setting of the injection timing switching reference | standard integration Ga (gaft) with respect to the water temperature (thws) at the time of starting. It is a flowchart which shows the routine of the fuel injection timing control at the time of starting performed in Embodiment 3 of this invention. It is a flowchart which shows the routine of the fuel injection timing control at the time of starting performed in Embodiment 4 of this invention. It is a figure which shows the setting of the intake TDC injection time (tautdc) with respect to engine speed (NE). It is a flowchart which shows the routine of the fuel injection timing control at the time of starting performed in Embodiment 5 of this invention. It is a flowchart which shows the routine of the fuel injection timing control at the time of starting performed in Embodiment 6 of this invention. It is a figure which shows the setting range of the opening timing of the intake valve at the time of the exhaust valve early closing control concerning Embodiment 7 of this invention. It is a figure which shows the opening / closing timing of the intake valve and exhaust valve at the time of exhaust valve early closing control concerning Embodiment 7 of this invention. It is a figure which shows the opening / closing timing of the intake valve and exhaust valve at the time of the exhaust valve early closing control concerning Embodiment 8 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Combustion chamber 12 Intake valve 14 Exhaust valve 16 Spark plug 18 Crankshaft 20 Starter 22 Intake valve timing control device 24 Exhaust valve timing control device 30 Intake pipe 32 Throttle 34 Fuel injection valve 36 Intake port 40 Exhaust port 50 ECU
52 Crank angle sensor 54 Water temperature sensor 56 Air flow sensor 58 Start switch EVO Exhaust valve opening timing EVC Exhaust valve closing timing IVO Intake valve opening timing IVC Intake valve closing timing

Claims (9)

In a start control device for an internal combustion engine having a fuel injection valve for injecting fuel into an intake port and an exhaust valve capable of adjusting a closing timing,
At least in the first cycle at the start, the closing timing of the exhaust valve is advanced from the intake top dead center, and the crank angle from the closing timing to the intake top dead center depends on the opening timing of the intake valve and the intake air. Exhaust valve closing timing control means for controlling to be larger than the crank angle between the top dead center and
Fuel injection timing control means for controlling the fuel injection timing of the fuel injection valve so that the fuel injection period overlaps the opening timing of the intake valve at least in the first cycle at the start;
A start control device for an internal combustion engine, comprising:   2. The start control device for an internal combustion engine according to claim 1, wherein the fuel injection timing control means controls the fuel injection timing so that the vicinity of the substantially center of the fuel injection period overlaps with the opening timing of the intake valve.   The fuel injection timing control means divides the fuel injection period into a plurality of times, one of the divided fuel injection periods overlaps with the opening timing of the intake valve, and the other period is within the closing period of the intake valve. 3. The start control device for an internal combustion engine according to claim 1, wherein the fuel injection timing is controlled as described above.   4. The fuel injection timing control means according to claim 3, wherein the fuel injection period overlapping with the opening timing of the intake valve is decreased in accordance with an increase in engine speed after the second cycle at the start. Start control device for internal combustion engine. In a start control device for an internal combustion engine having a fuel injection valve for injecting fuel into an intake port, an exhaust valve capable of adjusting a closing timing, and an intake valve capable of adjusting an opening timing,
Exhaust valve closing timing control means for controlling the closing timing of the exhaust valve to be at an advance side from the intake top dead center at least in the first cycle at the time of start;
An intake valve opening timing control means for controlling the opening timing of the intake valve at a first cycle at the time of starting so that the pressure of the combustion chamber of the internal combustion engine is higher than the pressure of the intake port;
Fuel injection timing control means for controlling the fuel injection timing of the fuel injection valve so that the fuel injection period overlaps the opening timing of the intake valve at least in the first cycle at the start;
A start control device for an internal combustion engine, comprising: In a start control device for an internal combustion engine having a fuel injection valve for injecting fuel into an intake port, an exhaust valve capable of adjusting a closing timing, and an intake valve capable of adjusting an opening timing,
Exhaust valve closing timing control means for controlling the closing timing of the exhaust valve to be at an advance side from the intake top dead center at least in the first cycle at the time of start;
An intake valve opening timing control means for controlling the opening timing of the intake valve at least in the first cycle at the time of starting so as to be when the blowback occurs from the combustion chamber to the intake port;
Fuel injection timing control means for controlling the fuel injection timing of the fuel injection valve so that the fuel injection period overlaps the opening timing of the intake valve at least in the first cycle at the start;
A start control device for an internal combustion engine, comprising:   The start control device for an internal combustion engine according to claim 5 or 6, wherein the intake valve opening timing control means sets the opening timing of the intake valve to be retarded from the closing timing of the exhaust valve.   The intake valve opening timing control means is configured to advance the intake valve from the intake top dead center by a crank angle equal to or smaller than a crank angle from the exhaust valve close timing to the intake top dead center. The start control device for an internal combustion engine according to claim 5 or 6.   The start of the internal combustion engine according to claim 5 or 6, wherein the exhaust valve closing timing control means sets the closing timing of the exhaust valve within 30 degrees in crank angle to an advance side of intake top dead center. Control device.

Images