JP4151268B2 - Stop control device for internal combustion engine with electromagnetically driven valve - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a stop control device for an internal combustion engine provided with an electromagnetically driven valve, and more particularly to a stop control device suitable for controlling an internal combustion engine provided with an intake valve or an exhaust valve constituted by an electromagnetically driven valve.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as disclosed in, for example, Japanese Patent Laid-Open No. 10-18820, an internal combustion engine including an intake valve and an exhaust valve configured by electromagnetically driven valves is known. This electromagnetically driven valve maintains a neutral position when not energized, and can perform a predetermined drive control to realize a valve closing position or a valve opening position. In such an internal combustion engine, since the drive timing of the intake valve and the exhaust valve can be freely controlled, it is possible to ensure a high degree of freedom in various controls as compared with the case where they are driven by a cam mechanism. .
[0003]
In the conventional internal combustion engine, when energization to the electromagnetically driven valve is stopped at the same time that the engine is required to stop, the intake valve and the exhaust valve are in a neutral state, that is, a half-open state at that time. In this case, there is a problem that the combustion gas flows back to the intake system in the cylinder in the explosion process, and a problem that the unburned gas flows back to the intake system in the cylinder in the compression stroke.
[0004]
Therefore, in the above-described conventional internal combustion engine, after the engine stop command is generated, the electromagnetically driven valve is driven until the combustion gas or unburned gas remaining in the cylinder is discharged to the exhaust system as exhaust gas. Control is to be continued. For this reason, in the conventional internal combustion engine, although the intake valve and the exhaust valve are constituted by electromagnetically driven valves, there is a problem that the combustion gas and the unburned gas flow back to the intake system when the engine is stopped. Can be reliably prevented.
[0005]
[Problems to be solved by the invention]
During operation of the internal combustion engine, the opening and closing timings of the intake valve and the exhaust valve are determined according to various demands such as improvement of fuel consumption. Therefore, the opening / closing timing is not necessarily suitable for scavenging the residual gas in the cylinder. In other words, in the conventional internal combustion engine, in order to prevent the backflow of combustion gas and unburned gas, the control of the electromagnetically driven valve is performed after the engine stop command. I will not. For this reason, the conventional internal combustion engine has a problem that it takes a certain amount of time until the scavenging of the remaining gas is finished after the stop command is issued.
[0006]
The present invention has been made to solve the above-described problems. After the engine stop command is issued, the scavenging is quickly performed by driving the electromagnetically driven valve according to a rule suitable for scavenging the remaining gas. It is an object of the present invention to provide a stop control device for an internal combustion engine that can be terminated in a short time.
[0007]
[Means for Solving the Problems]
  In order to achieve the above object, the invention according to claim 1 is a stop control device for an internal combustion engine provided with an electromagnetically driven valve that functions as an intake valve or an exhaust valve.
  First driving means for driving the electromagnetically driven valve according to a first rule during operation of the internal combustion engine;
  After the stop command for the internal combustion engine, instead of the first rule, the electromagnetic drive is performed according to the second rule that can scavenge the cylinder gas of the internal combustion engine with higher pump efficiency than the first rule. Second driving means for driving the valve;,
  The first rule is a rule for scavenging in-cylinder gas of an internal combustion engine with lower pump efficiency than the second rule.A stop control apparatus for an internal combustion engine.
  It is characterized by providing.
[0009]
  Claim2The described invention is claimed.1The internal combustion engine stop control device according to claim 1,
  A rotational speed detection means for detecting the engine rotational speed;
  A second rule setting means for setting the second rule according to the engine speed;
  It is characterized by providing.
[0010]
  Claim3The invention described in claim 1Or 2The internal combustion engine stop control device according to claim 1,
  The electromagnetically driven valve includes both an exhaust electromagnetically driven valve that functions as an exhaust valve and an intake electromagnetically driven valve that functions as an intake valve,
  When at least the engine speed belongs to a predetermined low rotation range, the exhaust electromagnetically driven valve is opened at the bottom dead center of the piston and closed at the top dead center of the piston. It is provided with the 2nd rule fixing means which makes the rule which makes a valve open at a piston top dead center and closes at a piston bottom dead center said 2nd rule.
[0011]
  Claim4The invention described in claims 1 to3A stop control device for an internal combustion engine according to any one of
  New injection prohibiting means for prohibiting the start of new fuel injection into the cylinder after the stop command of the internal combustion engine;
  In each cylinder, effective ignition processing means for performing an effective ignition process for burning unburned gas existing therein,
  In each cylinder, the first drive means is made effective until the exhaust valve is opened for the first time after the last effective ignition process is executed. After the valve opening, the first drive means is used instead. Drive rule switching means for enabling the second drive means;
  It is characterized by providing.
[0012]
  The invention according to claim 5 is a stop control device for an internal combustion engine provided with an electromagnetically driven valve that functions as an intake valve or an exhaust valve,
  Multi-stroke operation means for causing the internal combustion engine to perform multi-stroke operation during operation of the internal combustion engine;
  After the internal combustion engine stop command, the internal combustion engine is compared with the multi-stroke operation.In one cycleA small stroke operation means for performing a small stroke operation with a small number of strokes;
  It is characterized by providing.
[0013]
  Claim6The invention described in claims 1 to5A stop control device for an internal combustion engine according to any one of
  A flow resistance control mechanism for controlling the flow resistance of the intake passage of the internal combustion engine;
  After the stop command for the internal combustion engine, a mechanism control means for controlling the flow resistance control mechanism so that the flow resistance becomes a predetermined value or less;
  It is characterized by providing.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected to the element which is common in each figure, and the overlapping description is abbreviate | omitted.
[0015]
Embodiment 1 FIG.
FIG. 1 is a diagram for explaining the configuration of the first embodiment of the present invention. The configuration shown in FIG. 1 includes an internal combustion engine 10. An intake passage 12 and an exhaust passage 14 communicate with the internal combustion engine 10. The intake passage 12 includes an air filter 16 at an upstream end. An intake air temperature sensor 18 is assembled to the air filter 16.
[0016]
An air flow meter 20 is disposed downstream of the air filter 16. The air flow meter 20 is a sensor that detects an intake air amount Ga that flows through the intake passage 12. A throttle valve 22 is provided downstream of the air flow meter 20. The throttle valve 22 is an electronically controlled throttle valve that can control the throttle opening independently of the accelerator opening. In the vicinity of the throttle valve 22, a throttle sensor 24 for detecting the throttle opening degree TA and an idle switch 26 that is turned on when the throttle valve 22 is fully closed are arranged.
[0017]
A surge tank 28 is provided downstream of the throttle valve 22. Further, a fuel injection valve 30 for injecting fuel into the intake port of the internal combustion engine 10 is disposed further downstream of the surge tank.
[0018]
A catalyst 32 communicates with the exhaust passage 14. The catalyst 32 can store a certain amount of oxygen. If the exhaust gas contains unburned components such as HC and CO, the catalyst 32 oxidizes them using the stored oxygen. If the gas contains oxidizing components such as NOx, they can be reduced and the released oxygen can be stored. The exhaust gas discharged from the internal combustion engine 10 is purified by being treated as described above inside the catalyst 32.
[0019]
In the exhaust passage 14, upstream of the catalyst 32, exhaust O₂A sensor 34 is arranged. Exhaust O₂The sensor 34 is a sensor that changes the output according to the oxygen concentration in the gas to be detected. When the exhaust air-fuel ratio becomes rich, a voltage near 1 V is generated until the air-fuel ratio becomes lean thereafter. When the exhaust air-fuel ratio becomes lean, the sensor generates a voltage of about 0.1 V until the air-fuel ratio becomes rich thereafter.
[0020]
In the present embodiment, the catalyst 32 is provided in the exhaust passage 14. However, a NOx absorbent may be disposed in the exhaust passage 14 instead of the catalyst 32 or together with the catalyst 32. In this embodiment, the exhaust O₂Although the sensor 34 is provided, the exhaust passage 14 has an exhaust O 2.₂Instead of sensor 34 or exhaust O₂In addition to the sensor 34, an air-fuel ratio sensor that can linearly detect the air-fuel ratio may be arranged.
[0021]
The internal combustion engine 10 includes an intake electromagnetic drive valve 38 that drives the intake valve 36 with electromagnetic force, and an exhaust electromagnetic drive valve 42 that drives the exhaust valve 40 with electromagnetic force. Further, the internal combustion engine 10 is assembled with a spark plug 44 whose tip is exposed in the cylinder and a rotational speed sensor 46 for detecting the engine rotational speed NE.
[0022]
The intake electromagnetic drive valve 38 maintains the intake valve 36 in a neutral position, that is, a half-open position when not energized, and receives the drive signal supplied from the outside to move the intake valve 36 to a fully open position and a fully closed position. It is a mechanism that can do. Similarly, the exhaust electromagnetic drive valve 42 can maintain the exhaust valve 40 in the neutral position when not energized, and can move the exhaust valve 40 to the fully open position and the fully closed position in response to a drive signal supplied from the outside. Mechanism.
[0023]
The system of this embodiment includes an ECU (Electronic Control Unit) 50 as shown in FIG. The ECU 50 is connected to an ignition switch (IG switch) 52 and an accelerator opening sensor 54 together with the various sensors described above. The fuel injection valve 30, the intake electromagnetic drive valve 38, the exhaust electromagnetic drive valve 42, and the like described above are controlled by the ECU 50. Further, the spark plug 44 performs an ignition process at a timing determined by the ECU 50.
[0024]
Next, the operation of the system of this embodiment will be described with reference to FIGS.
FIG. 2 is a timing chart for explaining the operation of the system of this embodiment. In FIG. 2, # 1 to # 4 represent the first to fourth cylinders of the internal combustion engine 10, respectively. The horizontal axis corresponds to the crank angle, and the waveforms displayed together with the symbol Ex or In are the valve opening profiles of the exhaust valve 40 and the intake valve 36, respectively. Furthermore, hatched rectangular areas and timings indicated by arrows represent fuel injection periods and ignition timings, respectively.
[0025]
In the example shown in FIG. 2, the IG switch 52 is turned off during the fuel injection period of the # 1 cylinder. That is, this timing chart exemplifies a case where a stop command for the internal combustion engine 10 is issued during the fuel injection period of the # 1 cylinder.
[0026]
Among the valve opening profiles shown in FIG. 2, those indicated by thin lines are profiles determined so as to satisfy various demands for efficiently operating the internal combustion engine 10 such as realization of high fuel consumption. Hereinafter, the rule for determining the profile is referred to as “first rule”. FIG. 2 shows, as an example of the profile determined according to the first rule, the profile of the exhaust valve 40 in which the valve opening period is from before the bottom dead center (BDC) to immediately after the top dead center (TDC), and the top dead center. A profile of the intake valve 36 in which the valve opening period is from just before the point (TDC) to after the bottom dead center (BDC) is shown.
[0027]
Further, among the valve opening profiles shown in FIG. 2, those indicated by bold lines are profiles for operating the piston with the highest pump efficiency. Hereinafter, the rule for determining the profile is referred to as a “second rule”. FIG. 2 shows, as an example of a profile determined according to the second rule, the profile of the exhaust valve 40 in which the valve opening period is from the bottom dead center (BDC) to the top dead center (TDC), and the top dead center ( A profile of the intake valve 36 in which the valve opening period is from TDC) to bottom dead center (BDC) is shown.
[0028]
The valve timing for operating the internal combustion engine 10 efficiently may be different from the valve timing for the purpose of maximizing pump efficiency. That is, when the throttle is fully opened (at the time of WOT), the valve timing for maximizing the pump efficiency matches the valve timing for realizing efficient operation, but the idling state that is a general state before the internal combustion engine 10 is stopped. For example, there is a valve timing that maximizes the fuel consumption characteristics apart from the valve timing that maximizes the pump efficiency. For this reason, the valve timing determined in accordance with the first rule and the valve timing determined in accordance with the second rule are generally different.
[0029]
By the way, in the system of the present embodiment, when the IG switch 52 is turned off, the start of fuel injection into a new cylinder is prohibited. In the example shown in FIG. 2, since the fuel injection of the # 1 cylinder has already started when the IG switch 52 is turned off, the fuel injection to the cylinder # 1 is executed as usual. Thereafter, fuel injection into other cylinders is prohibited. Hereinafter, like the # 1 cylinder shown in FIG. 2, the cylinder that is supplied with the injected fuel last is referred to as a “final injection cylinder”.
[0030]
In the system according to the present embodiment, the ignition process is continuously performed on the cylinder in which the unburned gas remains in the cylinder even after the IG switch 52 is turned off. Hereinafter, the ignition process executed in a state where unburned gas exists in the cylinder is referred to as “effective ignition process”. That is, the system of the present embodiment continues the ignition process in the internal combustion engine 10 at least until the effective ignition process is performed on the fuel injected into the final injection cylinder.
[0031]
In the example shown in FIG. 2, since the # 1 cylinder is supplied with the injected fuel when the IG is turned off, after the IG is turned off, the effective ignition process is executed only once in order to burn the fuel. The That is, in this example, for the # 1 cylinder, after the IG switch 52 is turned off, the first ignition process performed for the # 1 cylinder is the last effective ignition process.
[0032]
For the # 3 cylinder, no unburned gas remains in the cylinder at the moment of IG off. Further, after that, unburned gas is not supplied into the cylinder. Therefore, for the # 3 cylinder, the effective ignition process is not executed after the IG is turned off. Therefore, in the example shown in FIG. 2, for the # 3 cylinder, the ignition process performed immediately before IG OFF is the last effective ignition process.
[0033]
For the # 4 cylinder and the # 1 cylinder, unburned gas remains in the cylinder at the moment of IG off. Therefore, for these cylinders, after the IG is turned off, the effective ignition process is executed only once. Therefore, in the example shown in FIG. 2, for the # 4 cylinder and the # 1 cylinder, the ignition process that is executed for the first time after the IG is turned off is the last effective ignition process.
[0034]
The last effective ignition process described above is performed on the fuel injected normally in all the cylinders. Therefore, it is desirable that the last effective ignition process is performed in a state where the intake air amount is controlled as usual in all the cylinders. Therefore, in the system of this embodiment, after the IG switch 52 is turned off, the valve opening profile of the intake valve 36 is not immediately switched. More specifically, the valve opening profile of the intake valve 36 is determined by the first rule for the cylinders for which the last effective ignition processing has not been executed even after the IG switch 52 is turned off, and the last effective ignition is determined. The decision rule is switched to the second rule from the cylinder for which the processing has been completed.
[0035]
Further, when the effective ignition process is executed in the internal combustion engine 10, the output of the internal combustion engine 10 changes according to the timing at which the exhaust valve 40 opens thereafter. That is, when the exhaust valve 40 is opened early after the effective ignition process (after the explosion stroke), the output of the internal combustion engine may be reduced by exhausting the combustion pressure early. On the other hand, if the opening timing of the exhaust valve is delayed after the effective ignition processing, the output of the internal combustion engine may be increased by converting the combustion pressure into an output over a long period of time. Therefore, in order to suppress the output fluctuation of the internal combustion engine 10, the valve opening profile is determined by a normal method until the exhaust valve 40 is opened after the last effective ignition process is performed. That is, it is desirable to be determined by the first rule.
[0036]
Therefore, in the system of the present embodiment, with respect to the valve opening profile of the exhaust valve 40, the valve opening timing is set to the first time until the exhaust valve 40 is opened for the first time after the last effective ignition process is executed. The rules are to decide. Then, from the timing of closing the exhaust valve 40 opened at that timing, the profile determination rule is switched to the second rule.
[0037]
In the system of the present embodiment, the rules for determining the opening profiles of the intake valve 36 and the exhaust valve 40 are switched based on the above concept. As a result of switching between the first rule and the second rule in this way, in the system of the present embodiment, after the IG switch 52 is turned off, a normal valve is not produced without causing an output fluctuation of the internal combustion engine 10. Switching from timing to valve timing suitable for scavenging is possible.
[0038]
FIG. 3 is a flowchart of an ignition / injection control routine executed by the ECU 50 to realize the functions related to the stop of the fuel injection after the IG is turned off and the execution of the effective ignition process among the functions described above.
In the routine shown in FIG. 3, it is first determined whether or not the IG switch 52 is turned off (step 100).
[0039]
When the IG switch 52 is turned off, the condition of step 100 is satisfied, and then execution of new fuel injection to a new cylinder is prohibited (step 102).
In the example shown in FIG. 2, the fuel injection to the # 1 cylinder is made the last fuel injection by the processing of step 102.
[0040]
Next, the cylinder that has been supplied with the injected fuel last, that is, the final injected cylinder is determined (step 104).
In the example shown in FIG. 2, the # 1 cylinder is determined as the final injection cylinder by the process of step 104.
[0041]
Next, it is determined whether or not the ignition of the final injection cylinder has ended, that is, whether or not the effective ignition process for burning the fuel injected last into the final injection cylinder has been executed (step 106).
[0042]
In the example shown in FIG. 2, the condition of step 106 is established by performing the ignition process in the # 1 cylinder which is the final injection cylinder. When this condition is satisfied, next, a process for ending the ignition control is executed (step 108).
As a result, thereafter, the supply of the ignition current to the spark plug 44 is stopped in all the cylinders.
[0043]
FIG. 4 is a flowchart of a valve timing control routine executed by the ECU 50 in order to realize the function of switching the determination rules of the valve opening profiles of the intake valve 36 and the exhaust valve 40 among the functions described with reference to FIG. . Note that the routine shown in FIG. 4 is a routine executed for each cylinder.
[0044]
In the routine shown in FIG. 4, it is first determined whether or not the IG switch 52 is turned off (step 110).
[0045]
As a result, if it is determined that the IG switch 52 is not turned off, the first rule is selected as the valve opening profile determination rule for the intake valve 36 and the exhaust valve 40 in order to operate the internal combustion engine 10 efficiently. (Step 112).
[0046]
On the other hand, if it is determined in step 110 that the IG switch 52 has been turned off, it is then determined whether or not the last effective ignition process has ended in the cylinder to be processed (step 1). 114).
[0047]
In the system of the present embodiment, an ignition history and a fuel injection history are stored for each cylinder. Specifically, in step 114, it is determined whether fuel injection has been started after the most recent ignition process. As a result, when it is determined that the fuel injection has been started, it is determined that the last effective ignition process has not yet ended in the cylinder. On the other hand, if it is determined that fuel injection has not started after the most recent ignition process, it is determined that the last effective ignition has ended in the cylinder.
[0048]
If it is determined in step 114 that the last effective ignition process in the cylinder has not yet been completed, the process of step 112 is continuously executed to use the first rule. On the other hand, if it is determined that the last effective ignition process has been completed, it is then determined whether or not the exhaust valve 40 has been opened after the ignition process (step 116).
[0049]
As a result, if it is determined that the exhaust valve 40 has not yet been opened after the last effective ignition process, the process of step 112 is continued to use the first rule. On the other hand, when it is determined that the exhaust valve 40 has already been opened, in order to achieve valve timing suitable for scavenging of the in-cylinder gas, as a rule for determining the valve opening profiles of the intake valve 36 and the exhaust valve 40, A second rule is selected (step 118).
[0050]
When the routine shown in FIG. 4 described above is executed for each cylinder, the valve timing of each cylinder is sequentially determined according to the first rule after the IG switch 52 is turned off as shown in FIG. It is possible to switch from the determined timing to the timing determined by the second rule.
[0051]
By the way, in the present embodiment, the second rule is a valve timing for operating the piston with the highest pump efficiency as described. According to this rule, for example, in a low engine speed range where the engine speed is sufficiently low, the opening timing of the exhaust valve 40 is determined from the bottom dead center (BDC) to the top dead center (TDC), and the intake valve 36 The valve opening time is determined from top dead center (TDC) to bottom dead center (BDC).
[0052]
According to such a valve opening profile, in-cylinder gas can be discharged to the exhaust system without performing unnecessary pump work in the process of moving the piston from the bottom dead center toward the top dead center. Further, fresh air can be taken into the cylinder from the intake system without performing unnecessary pump work in the process of moving the piston from the top dead center toward the bottom dead center. For this reason, according to said valve opening profile, the exhaust gas which remain | survives in each cylinder can be scavenged efficiently with the highest pump efficiency.
[0053]
By the way, the valve timing for operating the piston with the highest pump efficiency varies depending on the engine speed NE. The ECU 50 stores a map that defines the relationship between the valve timing that maximizes the pump efficiency and the engine speed NE. When the second rule is selected in step 118, the ECU 50 refers to the map and determines the optimum valve timing based on the engine speed NE. Therefore, according to the system of the present embodiment, the in-cylinder gas can always be scavenged with the highest pump efficiency regardless of the engine speed NE when the IG switch 52 is turned off.
[0054]
FIG. 5 is a flowchart of a valve drive stop control routine executed by the ECU 50 in order to end the valve drive for scavenging at an appropriate timing.
In the routine shown in FIG. 5, it is first determined whether or not the final injection cylinder has been determined (step 120).
[0055]
When the final injection cylinder is determined by the processing of step 104 (see FIG. 3), the condition of step 120 is satisfied, and then the determination processing of the leading cylinder is performed (step 122).
The first cylinder is the cylinder in which the switching of the profile determination rule is executed first, and is determined based on the final injection cylinder that has been determined. For example, in the example shown in FIG. 2, the final injection cylinder is determined as the # 1 cylinder, and the # 3 cylinder is determined as the leading cylinder based on the determination result. When the final injection cylinder is the # 3 cylinder, the # 4 cylinder, or the # 2 cylinder, the # 4 cylinder, the # 2 cylinder, or the # 1 cylinder is determined as the leading cylinder.
[0056]
Once the leading cylinder is determined, the number of scavenging cycles executed for that cylinder is then a predetermined number N.₀It is determined whether or not this is the case (step 124).
Here, a series of flow until the intake valve 36 is opened and fresh air is introduced into the cylinder, and then the exhaust valve 40 is opened and the fresh air is discharged is defined as one scavenging cycle.
[0057]
The processing of step 124 is performed by the number of scavenging cycles ≧ N₀It is repeatedly executed until the above condition is satisfied. As a result, when the above condition is satisfied, thereafter, the driving of the intake electromagnetic drive valve 38 and the exhaust electromagnetic drive valve 42 is stopped in order from the top cylinder. That is, in the example shown in FIG.₀When the scavenging cycle is executed, the power supply to the intake electromagnetic drive valve 38 and the exhaust electromagnetic drive valve 40 of the # 3 cylinder is stopped at that time. Thereafter, every time the exhaust stroke is sequentially completed in the # 4 cylinder, the # 2 cylinder, and the # 1 cylinder, the power supply to the intake electromagnetic drive valve 38 and the exhaust electromagnetic drive valve 40 of those cylinders is stopped.
[0058]
According to the above processing, in all cylinders, N₀Multiple scavenging cycles can be performed. Where N₀The number of times is a predetermined number of times necessary and sufficient for scavenging the exhaust gas in the cylinder. For this reason, according to the system of this embodiment, when the internal combustion engine 10 is stopped, the in-cylinder gas can be surely scavenged in all the cylinders.
[0059]
By the way, after the IG switch 52 is turned off, the number of scavenging cycles to be executed to replace the in-cylinder gas from the exhaust gas to the fresh air changes according to the exhaust pipe pressure at that time. In other words, when a high exhaust pipe pressure is generated when the IG switch 52 is turned off, it is difficult for the exhaust gas to flow out from each cylinder to the exhaust passage 14, so that the cylinder is less than when the exhaust pipe pressure is low. Many scavenging cycles are required for scavenging the internal gas.
[0060]
FIG. 6 is a flowchart of a modified example of the valve drive stop control routine executed by the ECU 50 in order to meet the above request. In FIG. 6, the same steps as those shown in FIG. 5 are denoted by the same reference numerals, and the description thereof is omitted or simplified.
[0061]
The routine shown in FIG. 6 is the same as the routine shown in FIG. 5 except that the processes in steps 130 to 134 are executed prior to the process in step 120. That is, in the routine shown in FIG. 6, it is first determined whether or not the IG switch 52 is turned off (step 130).
[0062]
As a result, if it is determined that the IG switch 52 has been turned off, the intake air amount GA at that time is then detected (step 132).
The operating state of the internal combustion engine 10 is reflected in the intake air amount GA. More specifically, the intake air amount GA has a correlation with the pressure of the exhaust gas discharged from the internal combustion engine 10, that is, the exhaust pipe pressure. Therefore, the intake air amount GA detected in this step 132 can be treated as a characteristic value of the exhaust pipe pressure when the IG switch 52 is turned off.
[0063]
In the routine shown in FIG. 6, next, the predetermined number of times N is determined based on the intake air amount GA detected in step 132.₀Is set (step 134).
The ECU 50 stores a map that defines the number of scavenging cycles necessary for scavenging the in-cylinder gas in relation to the intake air amount GA, that is, in relation to the exhaust pipe pressure. In step 134, the map is referred to for a predetermined number of times N corresponding to the exhaust pipe pressure.₀Is set.
[0064]
Thereafter, the predetermined number N set in this way₀The processing of steps 120 to 126 is executed using. In this case, when a high exhaust pipe pressure is generated at the moment when the IG switch 52 is turned off, the number of scavenging cycles can be increased as compared with a case where the exhaust pipe pressure is low. Therefore, according to the modification shown in FIG. 6, the scavenging cycle can always be executed without waste regardless of the operating state of the internal combustion engine 10 when the IG switch 52 is turned off.
[0065]
In the first embodiment described above, when the IG switch 52 is turned off, the process for scavenging the in-cylinder gas is executed. However, the timing at which the process should be performed is limited to this example. Is not to be done. For example, in an eco-run vehicle having a function of stopping idling when the vehicle is stopped, or a hybrid vehicle using both an internal combustion engine and a motor, a stop command is issued not only to the IG switch 52 but also to the internal combustion engine. It is good also as performing the process for the scavenging mentioned above whenever it emits.
[0066]
In the first embodiment described above, the valve timing determined by the second rule is determined based on the engine speed NE, but the present invention is not limited to this. That is, the valve timing determined by the second rule is always the opening timing of the exhaust valve 40 from the bottom dead center to the top dead center, and the opening timing of the intake valve 36 from the top dead center to the bottom dead center. It may be.
[0067]
In the first embodiment described above, the ECU 50 drives the intake electromagnetic drive valve 38 and the exhaust electromagnetic drive valve 40 in accordance with the first rule selected in step 112, so The "second drive means" according to claim 1 is realized by driving the intake electromagnetic drive valve 38 and the exhaust electromagnetic drive valve 40 according to the second rule selected in step 118, respectively. Has been.
[0068]
  Further, in the first embodiment described above, the ECU 50 detects the engine speed NE based on the output of the speed sensor 46, so that the above-mentioned claims are made.2The above-mentioned “rotation speed detecting means” sets the second rule based on the rotation speed NE, and thereby the claim.2The “second rule setting means” described is realized.
[0069]
  Further, in the first embodiment described above, the ECU 50 sets the valve opening profile illustrated in FIG.3The described “second rule fixing means” is realized.
[0070]
  Further, in the first embodiment described above, the ECU 50 executes the process of step 102 described above.4The above-described “new injection prohibiting means” executes the effective ignition process at a predetermined timing until the ignition control is terminated by the process of step 108.4The "effective ignition processing means" described above executes the processing of steps 110 to 118 described above.4The described “driving rule switching means” is realized.
[0071]
Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described with reference to FIGS. The system of the present embodiment uses the configuration of the first embodiment to cause the ECU 50 to further execute the routine shown in FIG. 8 and execute the routine shown in FIG. 9 instead of the routine shown in FIG. Can be realized.
[0072]
FIG. 7 is a timing chart for explaining the operation of the system of this embodiment. The timing chart shown in FIG. 7 is the same as the timing chart shown in FIG. 2 except that a timing at which the throttle valve 22 is fully opened is added.
[0073]
In the system of the present embodiment, in-cylinder gas scavenging processing is performed using the valve timing determined by the second rule after the IG switch 52 is turned off, as in the case of the first embodiment. At this time, the in-cylinder gas can be scavenged more efficiently as the intake pipe pressure is closer to the atmospheric pressure. Therefore, in this embodiment, after the IG switch 52 is turned off, the throttle valve 22 is fully opened at an appropriate timing.
[0074]
By the way, in the system of the present embodiment, even after the IG switch 52 is turned off, the intake stroke on the premise of the effective ignition process is executed in the final injection cylinder. In this intake stroke, it is desirable that the normal intake air amount be sucked into the final injection cylinder. That is, in the final injection cylinder, it is desirable that the throttle opening be controlled as usual while the intake stroke on the premise of the effective ignition process is being executed.
[0075]
Therefore, in the present embodiment, the throttle valve 22 is not fully opened immediately after the IG switch 52 is turned off, and the throttle valve 22 is fully opened after the intake stroke of the final injection cylinder is completed. Therefore, in the example shown in FIG. 2, the throttle valve 22 is fully opened in synchronization with the timing when the intake valve 36 of the # 1 cylinder, which is the final injection cylinder, is closed. According to such processing, after the IG switch 52 is turned off, switching from the normal operation to the scavenging cycle can be performed smoothly without changing the output of the internal combustion engine 10.
[0076]
FIG. 8 is a flowchart of a throttle control routine executed by the ECU 50 for realizing the above-described functions related to the throttle valve 22.
In the routine shown in FIG. 8, first, it is determined whether or not the final injection cylinder has been determined by the process of step 104 (see FIG. 3) (step 140).
[0077]
When the IG switch 52 is turned off and the final injection cylinder is determined, the condition of step 140 is satisfied. When this condition is satisfied, next, whether or not the intake valve 36 of the final injection cylinder has transitioned from the open state to the closed state, that is, the final intake stroke in the final injection cylinder on the premise of the effective ignition process is performed. It is determined whether or not the processing has been completed (step 142).
The intake electromagnetic drive valve 38 and the exhaust electromagnetic drive valve 42 incorporate a lift position sensor for detecting the lift position of the intake valve 36 or the exhaust valve 40. The ECU 50 executes the determination process of step 142 based on the output of the lift position sensor.
[0078]
When the condition of step 142 is satisfied, a process for fully opening the throttle valve 22 is executed (step 144).
When this process is executed, the ventilation resistance of the intake passage 12 becomes sufficiently small, and the intake pipe pressure becomes substantially atmospheric pressure. For this reason, in subsequent scavenging cycles, high pump efficiency is realized in all cylinders, and scavenging of in-cylinder gas is performed efficiently.
[0079]
In the routine shown in FIG. 8, it is next determined whether or not the driving of the intake electromagnetic drive valve 38 and the exhaust electromagnetic drive valve 42 has been stopped for all the cylinders, that is, whether or not the desired scavenging cycle has been completed for all the cylinders. (Step 146).
[0080]
As a result, when it is determined that the condition of step 146 is satisfied, energization to the throttle valve 22 is stopped (step 148).
[0081]
FIG. 9 is a flowchart of a valve drive stop control routine that the ECU 50 executes in order to end the valve drive for scavenging in the present embodiment. In FIG. 9, the same steps as those shown in FIG. 5 are denoted by the same reference numerals, and the description thereof is omitted or simplified.
[0082]
The routine shown in FIG. 9 is the same as the routine shown in FIG. 5 except that the processing in steps 120 and 122 is replaced with the processing in steps 150 and 152.
That is, in the routine shown in FIG. 9, it is first determined whether or not the intake negative pressure has become substantially zero, that is, whether or not it has become atmospheric pressure (step 150).
The intake negative pressure may be measured by providing an intake pressure sensor in the intake passage, or may be estimated by a known method from the intake air amount GA detected by the air flow meter 20.
[0083]
In the system of this embodiment, as described above, after the IG switch 52 is turned off, the throttle valve 22 is fully opened. For this reason, the intake negative pressure becomes substantially zero soon after the IG switch 52 is turned off. When the intake negative pressure becomes substantially 0, the condition of step 150 is satisfied, and then a process of determining the leading cylinder is executed (step 152).
In step 152, specifically, after the condition of step 150 is satisfied, the cylinder in which the intake valve 36 is opened next is determined as the leading cylinder. According to the above processing, the cylinder in which the intake stroke is executed for the first time after the intake negative pressure becomes substantially zero can be determined as the leading cylinder.
[0084]
Thereafter, the processing in steps 124 and 126 is executed in the same manner as in the routine shown in FIG. 5, with the cylinder determined in step 152 as the leading cylinder. As a result, in all cylinders, after the intake negative pressure becomes substantially zero, a predetermined number of times N₀Scavenging cycles are performed. According to such processing, after the IG switch 52 is turned off, the exhaust gas remaining in the cylinder can be replaced with fresh air efficiently and reliably in all the cylinders.
[0085]
In the second embodiment described above, the throttle valve 22 is fully opened after the IG switch 52 is turned off. However, the present invention is not limited to this. That is, the throttle valve 22 may be opened so that the airflow resistance of the intake passage 12 is reduced to the extent that efficient scavenging is possible.
[0086]
In the second embodiment described above, the valve drive stop is controlled by the routine shown in FIG. 9 while focusing on the fact that the intake negative pressure approaches the atmospheric pressure after the IG switch 52 is turned off. However, the method for controlling the stoppage is not limited to this. That is, also in this embodiment, the stop of valve driving may be controlled according to the routine shown in FIG.
[0087]
In the second embodiment described above, since the throttle valve 22 is electronically controlled, the ventilation resistance of the intake passage 12 is reduced by opening the throttle valve 22, but the present invention is not limited to this. It is not something. That is, when the throttle valve 22 is a mechanical type that opens and closes in conjunction with the accelerator opening, a known idle speed control valve (ISCV) is provided in parallel with the throttle valve 22, and this ISCV is electronically connected. The ventilation resistance of the intake passage 12 may be lowered by opening the valve. Further, when the throttle valve 22 is a mechanical type, an opener known as a mechanism for preventing the closed adhering during stoppage may be incorporated in the throttle valve 22 and the opener may be used to reduce the ventilation resistance. Good.
[0088]
  In the above-described second embodiment, the electronically controlled throttle valve 22 or the ISCV or opener provided together with the mechanical throttle valve 22 is the above-mentioned claim.6And the ECU 50 executes the processing of the above-mentioned step 144 to execute the processing of the above-mentioned step 144.6The described “mechanism control means” is realized.
[0089]
Embodiment 3 FIG.
Next, Embodiment 3 of the present invention will be described with reference to FIG. 10 and FIG. The system of the present embodiment can be realized by causing the ECU 50 to further execute the routine shown in FIG. 11 using the configuration of the first or second embodiment.
[0090]
  FIG. 10 is a timing chart for explaining the operation of the system of this embodiment. In the timing chart shown in FIG. 10, the intake stroke and the exhaust stroke are repeated in the cylinder where the scavenging process is started.ProcessThe timing chart shown in FIG. 7 is the same as that shown in FIG.
[0091]
  In the system according to the present embodiment, after the IG switch 52 is turned off, the in-cylinder gas scavenging process is performed using the valve timing determined by the second rule, as in the first or second embodiment. Is called. Here, in the first or second embodiment, the intake electromagnetic drive valve 38 and the exhaust electromagnetic drive valve 42 are 4 even during the scavenging process.ProcessIt is driven in a pattern that assumes driving.
[0092]
That is, in the first or second embodiment, even after the scavenging process is started, after the intake stroke is executed following the exhaust stroke, the compression stroke and the expansion stroke are performed with the intake valve 36 and the exhaust valve 40 being closed. After that, the exhaust stroke is executed again. After the scavenging process is started, fuel is not burned in the cylinder. Therefore, in this case, there is no practical benefit of performing the compression stroke and the expansion stroke.
[0093]
  In the system of the present embodiment, since the intake valve 36 and the exhaust valve 40 are electromagnetically driven, the operation of the internal combustion engine 10 is different from the case where they are cam-driven.ProcessThe number can be changed. More specifically, the intake valve 36 and the exhaust valve 40 are set to 4ProcessDriving in a pattern corresponding to drivingProcessIt is also possible to drive with a pattern corresponding to driving.
[0094]
  Therefore, in this embodiment, after the IG switch 52 is turned off and the scavenging process is started, the drive pattern of the intake valve 36 and the exhaust valve 40 is switched, and the intake stroke and the exhaust stroke are repeatedly executed 2ProcessThe internal combustion engine 10 is operated in the mode. In this case, the compression stroke and the expansion stroke are omitted, and the vertical movement of the piston is all used for scavenging the in-cylinder gas.ProcessCompared to operating in mode, pump work can be increased and scavenging efficiency can be increased.
[0095]
FIG. 11 is a flowchart of a valve timing control routine executed by the ECU 50 to realize the above function. Note that the routine shown in FIG. 11 is a routine executed for each cylinder.
[0096]
In the routine shown in FIG. 11, it is first determined whether or not the IG switch 52 has been turned off (step 160).
[0097]
  As a result, if it is determined that the IG switch 52 is not turned off, the internal combustion engine 10 may be operated in a normal manner.ProcessAn operation mode is selected (step 162).
  In this case, the ECU 50 has many to be realized.ProcessDriving (eg 4ProcessThe intake valve 36 and the exhaust valve 40 are driven in a pattern corresponding to (operation).
[0098]
On the other hand, if it is determined in step 160 that the IG switch 52 is turned off, it is next determined whether or not the last effective ignition process has been completed in the cylinder to be processed (step 1). 164).
More specifically, it is determined whether fuel injection has been started after the most recent ignition process. As a result, when it is determined that the fuel injection has been started, it is determined that the last effective ignition process has not yet ended in the cylinder. On the other hand, if it is determined that fuel injection has not started after the most recent ignition process, it is determined that the last effective ignition has ended in the cylinder.
[0099]
  If it is determined in step 164 that the last effective ignition process in the cylinder has not yet been completed,ProcessIn order to continue the operation mode, the process of step 162 is executed. On the other hand, if it is determined that the last effective ignition process has been completed, then a small amount is required to enable efficient scavenging.ProcessAn operation mode is selected (step 166).
  In this case, the ECU 50 isProcessDriving (eg 2ProcessThe intake valve 36 and the exhaust valve 40 are driven in a pattern corresponding to (operation).
[0100]
  As described above, according to the routine shown in FIG. 11, when the final effective ignition process is completed and the scavenging process is started in each cylinder, the operation of the internal combustion engine 10 is performed at that time. Many modesProcessLow from operation modeProcessSwitch to operation mode. For this reason, according to the system of the present embodiment, it is possible to realize higher scavenging by realizing higher pump efficiency than in the case of the first or second embodiment.
[0101]
  In the above-described third embodiment, the multi-stroke operation is described as a four-stroke operation and the small-stroke operation is described as a two-stroke operation. However, the present invention is not limited to this. That is, the multi-stroke operation may be other than the four-stroke operation, such as the six-stroke operation, and the low-stroke operation is more than the multi-stroke operation.In one cycleIt is sufficient if the number of strokes is small.
[0102]
  In the third embodiment described above, the function of the first or second embodiment, that is, the function of switching the determination rule of the valve opening profile of the intake valve 36 or the exhaust valve 40 from the first rule to the second rule, Operation of the internal combustion engine 10ProcessAlthough it is assumed to be used in combination with a function for switching the number, the present invention is not limited to this. That is, the latter function may be used separately from the former function.
[0103]
  In the above-described third embodiment, the ECU 50 executes the process of step 162 described above.ProcessThe “operating means” executes the process of step 166 to thereby reduce theProcessEach “operating means” is realized.
[0104]
【The invention's effect】
  Since the present invention is configured as described above, the following effects can be obtained.
  According to the first aspect of the present invention, during operation of the internal combustion engine, the electromagnetically driven valve is driven according to the first rule suitable for operating the internal combustion engine.High pump efficiency, suitable for scavenging in-cylinder gasThe electromagnetically driven valve can be driven according to the second rule.
[0106]
  Claim2According to the described invention, the second rule for scavenging the in-cylinder gas can be set to a rule capable of realizing efficient scavenging based on the engine speed.
[0107]
  Claim3According to the described invention, when at least the engine speed belongs to the predetermined low speed range, the exhaust valve is opened at the bottom dead center, the exhaust valve is closed at the top dead center, and the intake valve is opened. Furthermore, the intake valve can then be closed at bottom dead center. By using such valve timing in the low turning point region, it is possible to achieve the highest pump efficiency and efficiently scavenge the in-cylinder gas.
[0108]
  Claim4According to the described invention, in each cylinder, the electromagnetically driven valve can be driven according to the first rule until the exhaust valve is opened for the first time after the last effective ignition process is executed. Until the exhaust valve is opened for the first time after the last effective ignition processing, the valve timing affects the output of the internal combustion engine. On the other hand, after the valve is opened, combustion does not occur in the cylinder, so that the output of the internal combustion engine is not affected by the valve timing. Therefore, according to the present invention, the drivability is deteriorated by using the first rule while the valve timing affects the output of the internal combustion engine and using the second rule after the influence no longer occurs. It is possible to quickly end the scavenging without any trouble.
[0109]
  Claim5According to the described invention, during operation of the internal combustion engine, many suitable for operating the internal combustion engine.ProcessAfter adopting the operation mode and commanding to stop the internal combustion engine, a small amount suitable for quickly scavenging the in-cylinder gas.ProcessSwitch to operation mode.
[0110]
  Claim6According to the described invention, after the stop command for the internal combustion engine, it is possible to reduce the flow resistance of the intake passage and create a state in which scavenging is easy.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining a system configuration according to a first embodiment of the present invention.
FIG. 2 is a timing chart for explaining the operation of the system according to the first embodiment of the present invention.
FIG. 3 is a flowchart of an ignition / injection control routine executed in the first embodiment of the present invention.
FIG. 4 is a flowchart of a valve timing control routine executed in Embodiment 1 of the present invention.
FIG. 5 is a flowchart of a valve drive stop control routine executed in the first embodiment of the present invention.
FIG. 6 is a flowchart of a modified example of the valve drive stop control routine executed in the first embodiment of the present invention.
FIG. 7 is a timing chart for explaining the operation of the system according to the second embodiment of the present invention;
FIG. 8 is a flowchart of a throttle control routine executed in Embodiment 2 of the present invention.
FIG. 9 is a flowchart of a valve drive stop control routine executed in the second embodiment of the present invention.
FIG. 10 is a timing chart for explaining the operation of the system according to the third embodiment of the present invention.
FIG. 11 is a flowchart of a valve timing control routine executed in the third embodiment of the present invention.
[Explanation of symbols]
10 Internal combustion engine
12 Intake passage
14 Exhaust passage
22 Throttle valve
30 Fuel injection valve
36 Intake valve
38 Intake electromagnetic drive valve
40 Exhaust valve
42 Exhaust solenoid drive valve
44 Spark plug
50 ECU (Electronic Control Unit)

Claims (6)

A stop control device for an internal combustion engine having an electromagnetically driven valve that functions as an intake valve or an exhaust valve,
First driving means for driving the electromagnetically driven valve according to a first rule during operation of the internal combustion engine;
After the stop command for the internal combustion engine, instead of the first rule, the electromagnetic drive is performed according to the second rule that can scavenge the cylinder gas of the internal combustion engine with higher pump efficiency than the first rule. Second driving means for driving the valve ,
The first rule, the internal combustion engine stop control device according to claim rule der Rukoto scavenging at low pump efficiency than the cylinder interior gas of the internal combustion engine to the second rule. A rotational speed detection means for detecting the engine rotational speed;
A second rule setting means for setting the second rule according to the engine speed;
The stop control device for an internal combustion engine according to claim 1, comprising: The electromagnetically driven valve includes both an exhaust electromagnetically driven valve that functions as an exhaust valve and an intake electromagnetically driven valve that functions as an intake valve,
When at least the engine speed belongs to a predetermined low rotation range, the exhaust electromagnetically driven valve is opened at the bottom dead center of the piston and closed at the top dead center of the piston. 3. The internal combustion engine according to claim 1, further comprising: a second rule fixing unit that sets a rule for opening the valve at a piston top dead center and closing at a piston bottom dead center as the second rule. Stop control device. New injection prohibiting means for prohibiting the start of new fuel injection into the cylinder after the stop command of the internal combustion engine;
In each cylinder, effective ignition processing means for performing an effective ignition process for burning unburned gas existing therein,
In each cylinder, the first drive means is made effective until the exhaust valve is opened for the first time after the last effective ignition process is executed. After the valve opening, the first drive means is used instead. Drive rule switching means for enabling the second drive means;
The stop control device for an internal combustion engine according to any one of claims 1 to 3, further comprising: A stop control device for an internal combustion engine having an electromagnetically driven valve that functions as an intake valve or an exhaust valve,
Multi-stroke operation means for causing the internal combustion engine to perform multi-stroke operation during operation of the internal combustion engine;
A low stroke operation means for causing the internal combustion engine to perform a small stroke operation in which the number of strokes in one cycle is smaller than that in the multi stroke operation after the stop command of the internal combustion engine;
A stop control device for an internal combustion engine, comprising: A flow resistance control mechanism for controlling the flow resistance of the intake passage of the internal combustion engine;
After the stop command for the internal combustion engine, a mechanism control means for controlling the flow resistance control mechanism so that the flow resistance becomes a predetermined value or less;
The stop control device for an internal combustion engine according to any one of claims 1 to 5, further comprising:

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