JP3709595B2 - In-cylinder direct injection spark ignition engine controller - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control device for an engine such as an automobile, and more particularly to a control device for an in-cylinder direct injection spark ignition engine provided with a direct injection injector that directly injects fuel into a cylinder.
[0002]
[Prior art]
Conventionally known in-cylinder direct injection engines are provided with a direct injection injector that supplies fuel directly into the cylinder, so that it is theoretically possible to supply fuel even in a compression stroke when the intake valve is not open. However, in consideration of the homogenization of the air-fuel mixture due to the flow of the intake air and the time required for sufficient atomization of the injected fuel, fuel is supplied in the intake stroke in accordance with the conventional intake port injection type engine. There are many cases. Also by this method, since the wall flow is eliminated by direct injection, the advantages of the direct injection engine such as improved emission performance can be fully utilized.
[0003]
In such an engine, if the throttle is fully closed while the engine speed is relatively high, it is determined that the driver intends or allows deceleration, and the fuel supply is stopped. It generates deceleration and improves fuel efficiency.
When a predetermined condition such as when the throttle is opened is satisfied, it is determined that the intention to decelerate is interrupted, and the fuel supply is resumed. Even when the engine speed decreases, the fuel supply is restarted to prevent an unexpected engine stop (engine stall).
[0004]
When resuming the fuel supply, sudden changes in torque cause discomfort to the driver and adversely affect drivability. Therefore, the torque generated by retarding the ignition timing has been conventionally suppressed, or Japanese Patent Laid-Open No. 2-196149. As described, a torque operation or the like is performed by sequentially increasing the number of cylinders for restarting fuel injection.
[0005]
[Problems to be solved by the invention]
However, in such a conventional direct-injection direct-injection engine control apparatus, since the fuel supply is restarted from the cylinder that takes the intake stroke after the determination of the fuel supply restart is made, the determination of the fuel supply restart is made. Therefore, it is inevitable that there will be some time delay from when the torque is actually generated.
[0006]
FIG. 20 is a diagram showing in-cylinder pressure and generated torque corresponding to the combustion cycle when fuel supply is resumed in a four-cylinder direct injection gasoline engine. Now, with reference to FIG. 20, consider the case where the fuel supply is restarted when the throttle is opened from the fuel supply stop state. Timing t in the figure₀In the intake stroke injection engine, the fuel supply to the # 1 cylinder that has already entered the intake stroke is not completely in time, and the # 3 cylinder that finally takes the intake stroke is finally complete. Since the fuel supply is resumed, the in-cylinder pressure and the generated torque of the # 1 cylinder are as shown by the broken line in FIG. 20, resulting in a problem that the response is deteriorated.
[0007]
On the other hand, if the torque operation of retarding the ignition timing or increasing the number of cylinders that resume injection is eliminated or alleviated in order to improve the response, there is a problem that drivability deteriorates.
In addition, since the speed of speed reduction varies depending on the operating conditions, when the fuel supply is restarted due to the speed reduction, there is the highest possibility that the engine will fall into an engine stall (when the speed decreases suddenly). However, it is necessary to set the rotational speed for resuming the fuel supply to the safe side in consideration of the delay in torque generation so that the operation can be continued. However, with such a setting, there is a problem that the margin to the engine stall is excessively increased under other conditions, and the fuel consumption cannot be sufficiently improved.
[0008]
In view of such a conventional problem, an object of the present invention is to achieve both improvement in response and prevention of deterioration in drivability, and further improve fuel efficiency and engine stall resistance.
[0009]
[Means for Solving the Problems]
For this reason, in the present invention, the cylinders in the intake stroke when the throttle is opened do not stop the fuel injection, but take advantage of the direct injection method in which the compression stroke injection can be performed, and the ignition from the intake stroke to the compression stroke is performed. Fuel was supplied during the period until then, and the intake stroke injection was performed as usual for the cylinders thereafter.
[0010]
  That is, in the invention according to claim 1, as shown in FIG. 1, the supply determination means A for determining whether the fuel is to be supplied or stopped, and the fuel based on the operating conditions at the time of fuel supply. Supply amount setting means B for setting the supply amount, and direct injection of fuel into the cylinder based on the output of the supply amount setting meansAnd the intake stroke injection is performed after the fuel supply is restarted from the supply stop state by the supply determining means.An in-cylinder having an in-cylinder direct supply means C, an ignition timing setting means D for setting an ignition timing based on operating conditions at the time of fuel supply, and an ignition means E for igniting based on an output of the ignition timing setting means In the control device for the direct injection engine, when fuel is first supplied when the supply determining unit determines the transition from the supply stop state to the supply state, based on the outputs of the supply amount setting unit and the ignition timing setting unit. And a restart cylinder determining means F for determining whether or not the set supply amount can be supplied to the cylinder in the compression stroke at the time of the set ignition timing by the determined ignition timing. In this case, the fuel supply always performed in the compression stroke is restarted from the cylinder in the compression stroke, and when it is determined that it is impossible, the cylinder is always in the compression stroke from the cylinder in the intake stroke when determining the transition. Resume the fuel supply to beThen, the intake stroke injection is performed to the cylinders after the cylinder in the intake stroke when the transition is determined.The restarting cylinder switching means G is provided.
[0011]
  In the invention according to claim 2, when the resumption cylinder determining means supplies the fuel for the first time when the supply determining means determines the transition from the supply stop state to the supply state, the supply amount setting means and the ignition timing are supplied. Based on the output from the setting means, whether or not the set supply amount can be supplied to the cylinder in the compression stroke at the time of the determination of the transition from the supply stop state to the supply state by the set ignition timing. Always judge when transitioning, the cylinder resumedSwitchingThe means is always executed when the transition from the supply stop state to the supply state is determined, and when it is determined that supply to the cylinder in the compression stroke is possible at the time of the transition determination, the means starts from the cylinder in the compression stroke. The fuel supply always performed by the compression stroke injection is restarted. When it is determined that the fuel supply is impossible, the fuel supply always performed by the compression stroke injection is resumed from the cylinder in the intake stroke when the transition is determined.Then, the intake stroke injection is performed to the cylinders after the cylinder in the intake stroke when the transition is determined.It is characterized by that.
  In the invention according to claim 3, the supply amount setting means is applied only to the fuel supply performed by the restarting cylinder switching means, and the cylinder pressure detection means during the intake stroke and the exhaust stroke is determined from the pressure value in the cylinder. The amount of intake air into the cylinder is calculated by correcting with the conversion coefficient calculated based on the output of the engine, and the basic fuel supply amount is determined according to the amount of intake air.
[0012]
  In the invention according to claim 4,The supply amount setting means is applied only to fuel supply performed by the restart cylinder switching means, and a value correlated with the pressure value in the cylinder is based on the output of the pressure correlation value detection means during the intake stroke and the exhaust stroke. The pressure value in the cylinder is calculated by correcting with the calculated conversion coefficient, the intake air amount into the cylinder is calculated from the pressure value in the cylinder, and the basic fuel supply amount is calculated according to the intake air amount. It is determined.
[0013]
  When the fuel supply is restarted as described above, the intake stroke is described in terms of “homogenization of the air-fuel mixture due to the flow of intake air and securing of time for sufficient atomization of the injected fuel”. Although slightly inferior to the engine that performs only injection, the state of in-cylinder pressure and generated torque is as shown by the solid line in FIG. 20, and the generated torque rises faster than in the case of only intake stroke injection, improving the response. It becomes possible.
[0014]
In this case, since the fuel is supplied shortly after the throttle is opened, there is a possibility that the response cannot catch up when the air flow meter is used for measuring the intake air amount for calculating the fuel supply amount. In that case, the intake air amount may be approximately calculated from the output of the in-cylinder pressure sensor attached to each cylinder, and the fuel supply amount may be calculated based on the calculated amount.
[0015]
  there,Claim 5In the invention according toThe supply amount setting means calculates the intake air amount into the cylinder based on the output of the in-cylinder pressure detection means for detecting the pressure value in the cylinder, and determines the basic fuel supply amount according to the intake air amount. On the other hand, the predetermined number of combustions after restarting the fuel supply is calculated based on the intake air amount that is transiently calculated from the pressure value in the cylinder, and after the predetermined number of times, the intake air amount to the engine is calculated. Computation method switching means for computing the fuel supply amount based on the output of the intake air amount detection means for direct detection is provided.
  In the invention according to claim 6, the supply amount setting means calculates the pressure value in the cylinder based on the output of the pressure correlation value detection means for detecting a value correlated with the pressure value in the cylinder, The amount of intake air into the cylinder is calculated from the pressure value in the cylinder, and the basic fuel supply amount is determined according to the amount of intake air. The fuel supply amount is calculated based on the intake air amount calculated from the internal pressure value, and after a predetermined number of times, the fuel supply amount is calculated based on the output of the intake air amount detecting means for directly detecting the intake air amount to the engine. Computation method switching means for computation is provided.
[0016]
  Further, in the invention according to claim 7, the predetermined number of combustion times after resumption of fuel supplyDuringCompensation amount correction means for calculating a generated torque for each combustion from the in-cylinder pressure value and further correcting at least one of a supply amount correction coefficient for the next combustion and an ignition timing correction value based on the generated torque. Features.
  Further, in the invention according to claim 8, the supply amount setting means determines the basic fuel supply amount determined on the basis of the intake air amount as the generated torque after the predetermined number of combustion times after the fuel supply resumption determination by the supply determining means. The fuel supply amount is set by correcting with a predetermined supply amount correction coefficient corresponding to the number of times of combustion so as to control.
  Further, in the invention according to claim 9, the ignition timing setting means controls the generated torque with the basic ignition timing determined based on operating conditions for the predetermined number of combustion times after the fuel supply restart decision by the supply determining means. Thus, the ignition timing is set by correcting with a predetermined ignition timing correction value corresponding to the number of times of combustion.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 2 is a system configuration diagram showing an example of an in-cylinder direct injection engine to which the present invention is applied.
In the engine 1 of FIG. 2, intake is performed via a throttle valve 2, a surge tank 3, an intake manifold 4, and an intake valve 5, and fuel is directly supplied to a combustion chamber 7 from a direct injection injector 6 as in-cylinder direct supply means. Is done.
[0018]
The spark plug 8 as an ignition means is provided with an electrode for ignition facing the combustion chamber 7.
As means for detecting the operating condition / state of the engine 1, an air flow meter 9 provided upstream of the throttle valve 2 for measuring the intake air amount, an idle switch (not shown) that is turned on when the throttle valve 2 is fully closed, and the engine There is a crank angle sensor (not shown) for measuring the crank position of 1. The crank angle sensor is directly or indirectly connected to the crankshaft or the camshaft that rotates in conjunction with the crankshaft, and calculates the crank position (crank angle) and the rotational speed of the engine 1.
[0019]
In order to detect the combustion state, an in-cylinder pressure sensor 10 is installed as in-cylinder pressure detecting means. The air-fuel ratio is controlled by adjusting the fuel injection amount with the direct injection injector 6. In addition to this, a water temperature sensor 11 that measures the engine coolant temperature and an O that measures the oxygen concentration in the exhaust gas.₂A sensor 12 and the like are provided.
Further, input / output of information with the outside and various operations are realized by a circuit centered on the microcomputer shown in FIG. Various sensors such as the above-described air flow meter 9 are connected to the input port 13, and information thereof is input. The A / D converter 14 performs A / D conversion so that an analog signal among signals obtained from various sensors via the input port 13 can be handled by a computer. The CPU 15 executes a predetermined calculation based on the input data, and the result is output from the output port 16 as a signal for driving and controlling an external device.
[0020]
The ROM 17 stores a control program and various data described later in advance, and the RAM 18 temporarily stores information during program execution.
Next, a first embodiment of the present invention will be described.
FIG. 4 is a routine for determining fuel supply / stop, and is executed at predetermined time intervals.
[0021]
In step 1 (denoted as S1 in the figure, the same applies hereinafter), it is determined from the fuel supply stop flag Fc whether or not fuel is being supplied.
If fuel is being supplied (Fc = 0), it is determined in step 2 whether or not the idle switch is ON, and in step 3 whether or not the engine speed N is equal to or higher than a predetermined fuel supply stop speed Nfc. Determine.
[0022]
If it is determined in step 2 and step 3 that the idle switch is ON (throttle valve fully closed) and the engine speed N is equal to or higher than the predetermined fuel supply stop speed Nfc, the process proceeds to step 4 to supply fuel. The fuel supply is stopped by setting the stop flag Fc = 1.
If the determinations in step 2 and step 3 are other than the above, the fuel supply is continued.
[0023]
If it is determined in step 1 that the fuel supply is stopped (Fc = 1), it is determined in step 5 whether or not the idle switch has been turned off. In step 6, the engine speed N is determined. It is determined whether or not the fuel supply restart speed Nrc has fallen below.
If it is determined in step 5 and step 6 that the idle switch is turned off (in other words, the accelerator pedal is depressed) or the engine speed N falls below a predetermined fuel supply restart speed Nrc, In step 7, the fuel supply stop flag Fc = 0 is set, and the fuel supply is resumed.
[0024]
The above routine corresponds to supply determination means.
FIG. 5 is a routine for setting the fuel supply amount and the ignition timing when the fuel supply is restarted from the fuel supply stop state, and is executed when the fuel supply is restarted.
First, in step 11, a resumption flag Frec = 1 indicating that the fuel supply resumption procedure is in progress.
[0025]
In step 12, the initial value n is substituted into the counter C. This n is a constant that determines how many combustion costs it takes to smoothly transition from resumption of fuel supply to steady operation, and may be a value that differs for each operating condition, or may be a constant value regardless of the operating condition.
In step 13, the basic fuel supply amount Ti of the cylinder a during the compression stroke is calculated when it is determined to restart the fuel supply.
[0026]
Here, FIG. 6 is a flow showing a specific process for calculating the basic fuel supply amount Ti, and step 13 is executed in accordance therewith.
In step 31 of FIG. 6, the cylinder pressure Pcyl of the cylinder is read from the cylinder pressure sensor 10 at a predetermined timing. In step 32, the cylinder intake air amount Tp of the cylinder is calculated from the read cylinder pressure. In step 33, the basic fuel supply amount Ti is calculated based on Tp calculated in the preceding stage, and the process returns to the flow of FIG. Steps 31 to 33 correspond to supply amount setting means.
[0027]
In step 14 of FIG. 5, the basic fuel supply amount Ti calculated in the previous stage is multiplied by a supply amount correction coefficient Lean (C) to prevent deterioration of operability when fuel supply is resumed, and the corrected fuel supply amount Tiadj = Let Ti × Lean (C). Here, Lean (C) is a table value that is determined by the value of the counter C, and approaches 1 as the value of the counter C decreases, for example, as shown in FIG.
[0028]
In the subsequent step 15, the basic ignition timing Advmap at that time is read from the map based on the intake air amount Tp calculated in step 13 and the operating conditions such as the rotational speed N or the cylinder intake air-fuel ratio.
In step 16, it is determined whether or not it is possible to finish supplying the corrected fuel supply amount Tiadj to the cylinder a in the compression stroke by the read basic ignition timing Advmap. This step 16 corresponds to restart cylinder determining means.
[0029]
If it is determined in step 16 that the supply can be completed, Tiadj is substituted for the fuel supply amount Tiout in step 17, and Advmap is substituted for the ignition timing Adv in step 18. In step 19, the counter C is decremented by one.
Here, steps 15 and 18 correspond to ignition timing setting means.
When it is determined in step 16 that fuel cannot be supplied to the cylinder a during the compression stroke, or after the processing up to step 19 is completed, the routine proceeds to step 20.
[0030]
In step 20, it is determined whether or not the resumption of fuel supply is in the intake stroke, and whether or not the intake valve of the cylinder b that is going to the compression stroke next to the cylinder a is closed.
If the intake valve of the cylinder b is not closed, a time is waited until the cylinder is closed. If the intake valve is closed, the basic fuel supply amount Ti for the cylinder b is calculated in step 21. This step 21 uses steps 31 to 33 shown in FIG.
[0031]
In step 22, the obtained basic fuel supply amount Ti is multiplied by a supply amount correction coefficient Lean (C) to obtain Tiadj = Ti × Lean (C).
In the following step 23, the basic ignition timing Advmap of the cylinder b is read from a predetermined map.
Then, from the results of step 22 and step 23, the fuel supply amount Tiout = Tiadj is set at step 24, the ignition timing Adv = Advmap is set at step 25, and the value of the counter C is decremented by 1 at step 26, and the process is ended.
[0032]
Steps 17 to 26 correspond to restart cylinder switching means.
Here, the time waiting for the intake valve to close in step 20 is that when calculating the intake air amount from the in-cylinder pressure, the intake air amount is more accurate when the valve is closed and the cylinder is in the closed space Therefore, when the cylinder intake air amount is obtained by the air flow meter 9, it is not necessary to wait for this time.
[0033]
After the routine of FIG. 5 is completed, the fuel supply amount and ignition timing for each cylinder are set by the routine shown in FIG. 8 until the cumulative number of combustions after the fuel supply is resumed reaches n times. This routine uses the reference signal from the crank angle sensor
At every 180 ° CA).
First, at step 41, the supply restart flag Frec is checked. When Frec = 1, it is determined that the fuel supply procedure is in progress, and at step 42, whether the counter C is 0 or less (already n times fuel supply). Check whether the restart procedure is completed.
[0034]
If the counter C is not less than 0 in step 42, the counter is decremented by 1 in step 43, and the cylinder intake air amount Tp is calculated from the history of measured values of the air flow meter 9 in step 44. In step 45, the basic fuel supply amount Ti is calculated based on Tp calculated in step 44, and in step 46, the fuel supply amount Tiout = Ti × Lean (C) is obtained by multiplying Ti by the supply amount correction coefficient Lean (C). .
[0035]
In step 47, the basic ignition timing Advmap corresponding to the operating state such as the intake air amount Tp, the rotational speed N, the air-fuel ratio at that time is read from a predetermined ignition timing map, and in step 48, Advmap is substituted into the ignition timing Adv. finish.
If the counter C is 0 or less in step 42, it is determined that the fuel supply restart procedure has been completed. In step 49, the supply restart flag Frec is set to 0, and the following are set to normal combustion conditions.
[0036]
That is, in step 50, the cylinder intake air amount Tp is calculated from the measured value history of the air flow meter 9, and in step 51, the basic fuel supply amount Ti is calculated based on Tp. Without correcting this value, Ti is substituted into the fuel supply amount Tiout in step 52, and the ignition timing Adv is set in steps 47 and 48, and the process is terminated.
Further, when the supply restart flag Frec = 0 in step 41, the fuel supply restart procedure has been completed, so steps 50 to 52 and steps 47 to 48 are performed in the same manner, and the process is ended.
[0037]
Here, actual fuel supply and ignition based on the set values are executed by a higher-order interrupt procedure (not shown), which is the same in the following embodiments.
Examples of in-cylinder pressure and generated torque of each cylinder of the four-cylinder direct injection engine using the processing described so far are shown in FIGS.
The solid line in FIG. 9 shows the case where the fuel supply can be restarted from the cylinder a that was in the compression stroke when the determination of the fuel supply restart was made (resumption of fuel supply from the # 2 cylinder).
[0038]
Also, the solid line in FIG. 10 is the case where the fuel supply is restarted from the cylinder b that was in the intake stroke when the determination of the fuel supply restart was made (fuel supply restart from the # 1 cylinder).
In either case, the fuel supply can be restarted so that the torque is generated with good response and smoothness as compared with the case where the fuel supply is performed only in the conventional intake stroke (broken line in the figure).
[0039]
In the above description, when the cylinder intake air amount Tp is calculated from the in-cylinder pressure according to the procedure shown in FIG. 6, the in-cylinder pressure sensor can detect the absolute pressure value, but some sensors have a correlation with the pressure. Some values can be detected, but not absolute pressure values.
In this case, the procedure shown in FIG. 11 is used instead of FIG. 6 as the supply amount setting means. Here, it is assumed that the in-cylinder pressure sensor 10 as the pressure correlation value detection means detects a value proportional to the pressure.
[0040]
FIG. 12 is a diagram showing the output of the in-cylinder pressure sensor corresponding to the crank angle.
With reference to FIGS. 11 and 12 at the same time, in step 61, the sensor output V1 in the latest intake stroke of the cylinder is read, and in step 62, the sensor output V2 in the latest exhaust stroke of the cylinder is read.
Here, the in-cylinder pressure Pex (substantially equal to the exhaust pressure) in the exhaust stroke is almost known for each operating condition, and when the fuel supply is stopped, the in-cylinder pressure in the intake stroke is corrected to a certain level Pin. In step 63, a conversion coefficient K for converting the pressure correlation value to an absolute pressure is calculated as in the following equation.
K = (Pex−Pin) / (V2−V1)
In step 64, the output V of the in-cylinder pressure sensor is read. In step 65, the following equation is read.
The pressure correlation value read by the conversion coefficient K is converted into an absolute pressure value.
[0041]
Pcyl = Pin + K × (V−Vin)
Here, Vin is a stored value of the in-cylinder pressure sensor output during the intake stroke.
In step 66, the cylinder intake air amount Tp is calculated based on the absolute pressure obtained in step 65, and in step 67, the basic fuel supply amount Ti is calculated based on Tp.
[0042]
In the first embodiment described above, after the fuel supply is resumed, the predetermined number of combustions corrects the fuel supply amount so that the torque is recovered smoothly. This is because the ignition timing is used instead of the fuel supply amount. It is good also as a structure which correct | amends.
Next, a second embodiment using ignition timing correction will be described.
FIG. 13 is a flowchart showing a procedure for correcting the ignition timing when the fuel supply is resumed.
[0043]
First, when it is determined by the routine of FIG. 2 that the fuel supply is restarted, the restart flag Frec indicating that the fuel supply restart procedure is in progress is set to 1 in step 71, and in step 72, the initial value n is assigned to the counter C. To do.
Next, at step 73, the basic fuel supply amount Ti is calculated in accordance with the processing of FIG. 6 or FIG.
[0044]
In step 74, the basic ignition timing Advmap at that time is read from a predetermined map based on operating conditions such as the intake air amount Tp and the rotational speed N. In the following step 75, the ignition timing correction value Ret (C) is subtracted (retarded) from the basic ignition timing Advmap in order to prevent deterioration in drivability when the fuel supply is resumed, and Advadj = Advmap−Ret (C). Here, Ret (C) is a table value that decreases as the value of the counter C decreases, for example, as shown in FIG.
[0045]
In step 76, it is determined whether or not the basic fuel supply amount Ti can be injected into the cylinder a during the compression stroke by the corrected ignition timing.
If it is determined that the supply can be completed in step 76, Ti is substituted for the fuel supply amount Tiout in step 77, Advadj is substituted for the ignition timing Adv in step 78, and the value of the counter C is decreased by 1 in step 79.
[0046]
When it is determined in step 76 that fuel cannot be supplied to the cylinder a during the compression stroke, or when the processing up to step 79 is completed, the routine proceeds to step 80, and when it is determined to restart the fuel supply. It is determined whether or not the intake valve of the cylinder b that was in the air stroke has been closed.
If the intake valve is not closed, a time is waited until the intake valve is closed. If the intake valve is closed, the basic fuel supply amount Ti for the cylinder b is calculated in step 81 in the same manner as in step 73.
[0047]
In step 82, the basic ignition timing Advmap is read from a predetermined map in the same manner as in step 74. In step 83, correction by Ret (C) is performed, and Advadj = Advmap−Ret (C). In step 84, Ti is substituted for the fuel supply amount Tiout of the cylinder b in the intake stroke, and in step 85, the ignition timing Advadj corrected for retarding is substituted in the ignition timing Adv. In step 86, the value of the counter C is decreased by one. finish.
[0048]
Here, the time waiting in step 80 is the same as in the first embodiment.
After the routine of FIG. 13 is completed, the fuel supply amount and the ignition timing for each cylinder are set by the routine shown in FIG. 15 until the cumulative number of combustion after the fuel supply restarts reaches n times. This routine uses the reference signal from the crank angle sensor
At every 180 ° CA).
First, in step 91, the value of the supply restart flag Frec is checked. If the flag is 1, it is determined that the fuel supply procedure is in progress. In step 92, whether or not the counter C is 0 or less (already n times of fuel supply). Check whether the restart procedure is completed.
[0049]
If the counter is not less than 0 in step 92, the counter is decremented by 1 in step 93, and the cylinder intake air amount Tp is calculated from the history of measured values of the air flow meter 9 in step 94.
In step 95, the basic ignition timing Advmap corresponding to the operation state such as the intake air amount Tp, the rotational speed N, the air-fuel ratio at that time is read from a predetermined ignition timing map, and in step 96, retard correction Advmap-Ret (C ) Is substituted into the ignition timing Adv.
[0050]
In step 97, the basic fuel supply amount Ti is calculated based on Tp calculated in step 94. In step 98, Ti is substituted for the fuel supply amount Tiout, and the process is terminated.
If the counter C is 1 or less in step 92, it is determined that the fuel supply restart procedure has been completed. In step 99, the supply restart flag Frec is set to 0, and the following are set to normal combustion conditions.
[0051]
That is, in step 100, the cylinder intake air amount Tp is calculated from the history of measured values of the air flow meter 9, and in step 101, the basic ignition timing Advmap is read from a predetermined ignition timing map based on Tp. In step 102, the basic ignition timing Advmap is not corrected, but is substituted into the ignition timing Adv. In steps 97 and 98, Ti is substituted into the fuel supply amount Tiout, and the process is terminated.
[0052]
If the supply restart flag Frec is not set in step 91, the fuel supply restart procedure is completed, and thus the procedures of steps 100 to 102 and steps 97 to 98 are similarly completed.
Even when the second embodiment is applied, when the fuel supply is restarted from the cylinder a that was in the compression stroke when the determination of the fuel supply restart was made, the in-cylinder pressure and the generated torque are When the fuel supply is resumed from the cylinder b during the intake stroke because the timing of the fuel supply restart is late and the fuel supply is resumed from the cylinder b during the intake stroke, as shown by the solid line in FIG. (Fuel supply resumes from # 1 cylinder).
[0053]
In either case, as in the first embodiment, the fuel is responsive and has a smooth torque generation as compared with the case where fuel is supplied only by the conventional intake stroke (broken line in the figure). Supply can be resumed.
Next, a third embodiment is shown.
This uses both the torque correction by correcting the fuel supply amount used in the first embodiment and the torque correction by correcting the ignition timing used in the second embodiment, as shown in FIGS. It is executed by the procedure.
[0054]
FIG. 16 is a flowchart showing a procedure for correcting both the fuel supply amount and the ignition timing when the fuel supply is resumed.
In steps 111 to 116, similarly to the first and second embodiments, the corrected fuel supply amount Tiadj (= Ti × Lean (C)) corrected by the supply amount correction coefficient Lean (C), and the ignition timing A corrected ignition timing Advadj (= Advmap−Ret (C)) corrected by the correction value Ret (C) is calculated.
[0055]
If it is determined in the following step 117 that the fuel supply can be resumed from the cylinder a in the compression stroke, the fuel supply amount Tiout is set to Tiadj and the ignition timing Adv is set to Advadj in steps 118 and 119. Substituting and decrementing the value of the counter C by one.
If it is determined in step 117 that it is impossible to restart the fuel supply from the cylinder a during the compression stroke, or if the processing up to step 120 is completed, the fuel supply is performed in steps 121 to 125. In the state where the valve of the cylinder B that was in the intake stroke when the resumption of the engine is judged to be closed, the fuel supply amount Tiout (= Ti × Lean (C)) and the ignition timing Adv (= Advmap−Ret) (C)) is set based on the same expression, and the value of the counter C is decremented by 1 in step 126 and the process is terminated.
[0056]
FIG. 17 is a routine for setting the fuel supply amount and the ignition timing for each cylinder until the cumulative number of combustion after the resumption of fuel supply reaches n after the completion of the routine of FIG.
Here again, as in the first and second embodiments, the supply restart flag Frec is checked in step 131, and if the flag is 1, it is determined that the fuel supply procedure is in progress. Check if it is 0 or less.
[0057]
If the counter is not less than 0 in step 132, the counter is decremented by 1 in step 133, and the cylinder intake air amount Tp is calculated from the history of measured values of the air flow meter 9 in step 134. In steps 135 to 138, the lean-corrected fuel supply amount Tiout (= Ti × Lean (C)) and the retard-corrected ignition timing Adv (= Advmap−Ret (C)) during the fuel supply restart procedure are set. To finish.
[0058]
Also, if the supply restart flag Frec is 0 in step 131 and if the counter C is 0 or less in step 132, the fuel supply restart procedure is complete, so the normal conditions are used in steps 140 to 144. The fuel supply amount Tiout (= Ti) and the ignition timing Adv (= Advmap) are set and the process ends.
In this embodiment, the same counter C is used for the fuel supply amount correction and the ignition timing correction, and the number of corrections is the same n times. However, these are different counters C1 and C2, and the correction times are also n1. And n2, the number of fuel supply corrections and the number of ignition timing corrections may be set separately.
[0059]
Next, a fourth embodiment will be described.
In the first to third embodiments, the amount of cylinder intake air in the cylinder b that was in the intake stroke when the determination of restart of fuel supply was made is calculated from the output of the in-cylinder pressure sensor 10 ( The cylinder intake air amount of the subsequent cylinders is calculated from the history of measured values of the air flow meter 9. However, when the time delay until the air flow meter 9 can detect the correct intake air amount is large, the cylinder intake air is determined based on the detection value of the in-cylinder pressure sensor 10 for a predetermined period corresponding to the time delay. The amount may be calculated, and then the process may proceed to cylinder intake air amount calculation based on the detection value of the air flow meter 9.
[0060]
FIG. 18 is a routine showing a procedure for switching between the calculation of the cylinder intake air amount based on the detection value of the in-cylinder pressure sensor 10 and the calculation of the cylinder intake air amount based on the history of measured values of the air flow meter 9. In this embodiment, this routine can be used in place of step 44 and step 50 of FIG.
When this routine is used in the first embodiment, simultaneously with the setting of the counter C in step 12 of FIG. 5, the initial value Mn is set to the down counter M that is subtracted for each combustion when the fuel supply is resumed. In step 151, it is checked whether the counter M is 0 or less (whether the cylinder intake air amount calculation period by the in-cylinder pressure sensor has ended Mn times).
[0061]
If the counter M is not less than 0, the cylinder intake air amount Tp is calculated based on the value detected by the in-cylinder pressure sensor 10 at step 152, and the counter M is decremented by 1 at 153 and the process is terminated.
If the counter M becomes 0 or less in step 151, the cylinder intake air amount is calculated based on the history of the measured value of the air flow meter 9 in step 154, and the process ends.
[0062]
The above routine corresponds to the calculation method switching means.
Here, the initial value Mn of the counter M is a value corresponding to a time constant until the air flow meter 9 can detect an accurate intake air amount, and may be different for each operating condition, regardless of the operating condition. It may be a constant value.
The routine of FIG. 18 can be similarly used in the second and third embodiments.
[0063]
Next, a fifth embodiment will be described.
In the first to fourth embodiments, when the fuel supply amount and the ignition timing are corrected in order to correct the torque at the time of restarting the fuel supply, a supply amount correction coefficient Lean (C) which is a predetermined table value or an ignition Although the timing correction value Ret (C) is used, these can be used as variables to be further corrected based on the generated torque for each cycle obtained from the output of the in-cylinder pressure sensor 10 mounted on each cylinder. Good.
[0064]
FIG. 19 shows an example of a routine for calculating the generated torque (indicated mean effective pressure) for each cycle from the in-cylinder pressure value every 4 ° CA, and is executed for each exhaust top dead center of each cylinder.
First, at step 161, the counter S and the integral value P are cleared.
Next, in step 162, the in-cylinder pressure Pcyl at that time is read, and in step 163, the volume change rate dV (S) at the crank angle at that time is read from the map.
[0065]
In step 164, the product of Pcyl read in step 162 and the map value dV (S) read in step 163 is calculated, and dP = Pcyl × dV (S). In step 165, dP is added to the previous integrated value P by the equation P = P + dP, and this is set as the new integrated value P. In step 166, the value of the counter S is incremented by one.
[0066]
In Step 167, it is checked whether or not S> 180 (720 ° CA has been completed). If not satisfied, the process proceeds to Step 168. After waiting for the crank angle to advance by 4 ° CA, the process returns to Step 162. When S> 180 is established in step 167, the indicated mean effective pressure Pi is calculated from the integral value P and the stroke volume Vs in step 169 by the formula Pi = P / Vs.
[0067]
In step 170, the generated torque Ui is obtained from the indicated mean effective pressure Pi, and in step 171 the generated torque Ui is compared with the target value U of the generated torque at the time of resumption of fuel supply obtained in advance for each operating condition. If there is no difference between the generated torque Ui and the target torque U, the process is terminated. If there is a difference, in step 172, the correction coefficient Lean (C) and / or the correction value Ret (C ) Is corrected and the process ends.
[0068]
The above routine corresponds to correction amount correction means.
In this way, even if hardware changes with time such as changes in the operating environment and changes in injector characteristics occur, the torque generated when the fuel supply is resumed can be set to a desirable value.
[0069]
【The invention's effect】
As described above, according to the present invention, when it is determined that good combustion can be achieved in a cylinder that is in the compression stroke when it is determined that the fuel supply is restarted, the cylinder in the compression stroke Otherwise, by restarting the fuel supply from the cylinder during the intake stroke, the fuel supply is restarted at a cycle earlier than in the case of the conventional port injection, and the predetermined combustion cycle after the restart of the fuel supply is By performing torque control by correction and correction of ignition timing, both improvement in response and prevention of deterioration in drivability can be achieved, and resistance to engine stall can be improved.
[0070]
  That is,Claims 1 to 6According to the invention according to the present invention, when the fuel supply is resumed from the fuel supply stop state in the in-cylinder direct injection engine, the fuel supply restart at that time is in an optimum condition depending on the timing when the fuel supply restart is determined. This can be executed from the cylinder. As a result, there is an effect that an improvement in response and an improvement in fuel consumption can be achieved by reducing the number of revolutions for restarting fuel supply.
[0071]
  In particular, according to the third aspect of the invention, even when the responsiveness of the intake air amount sensor is not high, the intake air amount at the time of resumption of fuel supply can be quickly obtained, and the optimum fuel supply amount can be set. effective.
  According to the invention of claim 4, even when the absolute pressure value in the cylinder cannot be detected, the intake air amount at the time of resumption of fuel supply can be quickly obtained, and the optimum fuel supply amount is set. There is an effect that can be done.
[0072]
  According to the fifth and sixth aspects of the invention, when the intake air amount immediately after the fuel supply is resumed is detected directly, the predetermined period after the fuel supply is resumed even if the detected value is not highly responsive. By detecting the intake air amount approximately from the in-cylinder pressure value, there is an effect that the required fuel amount can be obtained quickly and accurately.
  Moreover, according to the invention which concerns on Claim 7, the generated torque after fuel supply resumption is adjusted correctly, and there exists an effect that a more desirable characteristic can be acquired.
[0073]
  According to the eighth aspect of the present invention, when the fuel supply is resumed from the state where the fuel supply is stopped, the amount of fuel to be supplied is controlled, and the generated torque is adjusted so that the drivability when the fuel supply is resumed. There is an effect that it is possible to alleviate the deterioration.
  According to the ninth aspect of the present invention, when the fuel supply is resumed from the state where the fuel supply is stopped, the ignition timing is controlled and the generated torque is adjusted so that the drivability when the fuel supply is resumed is deteriorated. There is an effect that can be reduced.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a basic configuration of the present invention.
FIG. 2 is a system configuration diagram showing an engine portion of an embodiment of the present invention.
FIG. 3 is a system configuration diagram illustrating a circuit portion of an embodiment of the present invention.
FIG. 4 is a flowchart for determining fuel supply / stopping executed at predetermined time intervals.
FIG. 5 is a flowchart for setting a fuel supply restart cylinder, fuel supply amount, ignition timing, and fuel supply amount correction method;
FIG. 6 is a flowchart showing a specific process for calculating a basic fuel supply amount Ti.
FIG. 7 is a view showing an example of a table for determining a supply amount correction coefficient Lean (C) from the value of the counter C.
FIG. 8 is a flowchart for setting a fuel supply amount and ignition timing for each cylinder up to n times of cumulative combustion after restarting fuel supply.
FIG. 9 is a diagram showing in-cylinder pressure and generated torque when fuel supply is restarted from a cylinder that was in the compression stroke when fuel supply restart determination was made.
FIG. 10 is a diagram showing in-cylinder pressure and generated torque when fuel supply is resumed from a cylinder that was in the intake stroke at the time of fuel supply resumption determination.
FIG. 11 is a flowchart for calculating a fuel supply amount based on a correlation value of in-cylinder pressure.
FIG. 12 is a diagram showing the output of the in-cylinder pressure sensor corresponding to the crank angle.
FIG. 13 is a flowchart for setting a cylinder for restarting fuel supply, a fuel supply amount, an ignition timing, and a method for correcting the ignition timing.
FIG. 14 is a view showing an example of a table for determining the ignition timing correction value Ret (C) from the value of the counter C.
FIG. 15 is a flowchart for setting a fuel supply amount and ignition timing for each cylinder up to n times of cumulative combustion after restarting fuel supply.
FIG. 16 is a flowchart showing a procedure for correcting both the fuel supply amount and the ignition timing when the fuel supply is resumed.
FIG. 17 is a flowchart for setting the fuel supply amount and ignition timing for each cylinder up to n times of cumulative combustion after restarting the fuel supply.
FIG. 18 is a flowchart showing a switching procedure for calculating the cylinder intake air amount.
FIG. 19 is a flowchart for calculating the generated torque for each cycle from the in-cylinder pressure value for every 4 ° CA.
FIG. 20 is a diagram showing in-cylinder pressure and generated torque when resuming fuel supply between a port injection engine and a direct injection engine.
[Explanation of symbols]
1 engine
2 Throttle valve
3 Surge tank
4 Intake manifold
5 Intake valve
6 Direct injector
7 Combustion chamber
8 Spark plug
9 Air flow meter
10 In-cylinder pressure sensor
11 Water temperature sensor
12 O₂Sensor

Claims (9)

Supply determination means for determining whether to supply or stop supplying fuel;
A supply amount setting means for setting a fuel supply amount based on operating conditions at the time of fuel supply;
In-cylinder direct supply means for directly injecting and supplying fuel into the cylinder based on the output of the supply amount setting means, and performing intake stroke injection after resumption of fuel supply from the supply stop state by the supply determining means ;
Ignition timing setting means for setting an ignition timing based on operating conditions at the time of fuel supply;
Ignition means for igniting based on the output of the ignition timing setting means;
In the in-cylinder direct injection engine control device having
When the fuel is first supplied when the supply determining unit determines the transition from the supply stop state to the supply state, the set supply amount is set based on the outputs of the supply amount setting unit and the ignition timing setting unit. Resuming cylinder determining means for determining whether it is possible to supply to the cylinder in the compression stroke at the time of determining the transition by the ignition timing;
When it is determined that it is possible, the fuel supply performed by the compression stroke injection is always restarted from the cylinder that is in the compression stroke, and when it is determined that it is not possible, the cylinder that is in the intake stroke when determining the transition Resuming cylinder switching means for always restarting the fuel supply performed by the compression stroke injection, and performing the intake stroke injection to the cylinder after the cylinder in the intake stroke at the time of the transition determination ;
An in-cylinder direct injection engine control device characterized by comprising: The restart cylinder determining means is set based on the outputs of the supply amount setting means and the ignition timing setting means when supplying fuel for the first time when the supply determining means determines the transition from the supply stop state to the supply state. Whether or not it is possible to supply to the cylinder in the compression stroke at the time of the determination of the transition by the set ignition timing, always at the time of determination of the transition from the supply stop state to the supply state,
The restarting cylinder switching means is always executed when the transition from the supply stop state to the supply state is determined, and when it is determined that the cylinder can be supplied to the cylinder in the compression stroke when the transition is determined, the compression stroke is performed. always resumes fuel supply performed by the compression stroke injection, if it is determined that it is impossible to resume the fuel supply to be performed always compression stroke injection from a cylinder in the intake stroke at the time the determination of the transition from one cylinder 2. The in- cylinder direct injection engine control device according to claim 1 , wherein an intake stroke injection is performed to a cylinder after a cylinder in an intake stroke when the transition is determined . Supply determination means for determining whether to supply or stop supplying fuel;
A supply amount setting means for setting a fuel supply amount based on operating conditions at the time of fuel supply;
In-cylinder direct supply means for directly injecting and supplying fuel into the cylinder based on the output of the supply amount setting means, and performing intake stroke injection after resumption of fuel supply from the supply stop state by the supply determining means ;
Ignition timing setting means for setting an ignition timing based on operating conditions at the time of fuel supply;
Ignition means for igniting based on the output of the ignition timing setting means;
In the in-cylinder direct injection engine control device having
When the fuel is first supplied when the supply determining unit determines the transition from the supply stop state to the supply state, the set supply amount is set based on the outputs of the supply amount setting unit and the ignition timing setting unit. Resuming cylinder determining means for determining whether it is possible to supply to the cylinder in the compression stroke at the time of determining the transition by the ignition timing;
If it is determined to be a resumes fuel supply from the cylinder in the compression stroke, if it is determined that it is impossible to resume the fuel supply from the cylinder in the intake stroke at the time the determination of the transition, the Resuming cylinder switching means for performing the intake stroke injection to the cylinder after the cylinder in the intake stroke at the time of transition determination ;
Provided,
The supply amount setting means is applied only to the fuel supply performed by the restart cylinder switching means, and the pressure value in the cylinder is calculated by a conversion coefficient calculated based on the output of the in-cylinder pressure detection means during the intake stroke and the exhaust stroke. A control device for a direct injection type in-cylinder engine, which corrects to calculate an intake air amount into the cylinder and determines a basic fuel supply amount according to the intake air amount. Supply determination means for determining whether to supply or stop supplying fuel;
A supply amount setting means for setting a fuel supply amount based on operating conditions at the time of fuel supply;
In-cylinder direct supply means for directly injecting and supplying fuel into the cylinder based on the output of the supply amount setting means, and performing intake stroke injection after resumption of fuel supply from the supply stop state by the supply determining means ;
Ignition timing setting means for setting an ignition timing based on operating conditions at the time of fuel supply;
Ignition means for igniting based on the output of the ignition timing setting means;
In the in-cylinder direct injection engine control device having
When the fuel is first supplied when the supply determining unit determines the transition from the supply stop state to the supply state, the set supply amount is set based on the outputs of the supply amount setting unit and the ignition timing setting unit. Resuming cylinder determining means for determining whether it is possible to supply to the cylinder in the compression stroke at the time of determining the transition by the ignition timing;
If it is determined to be a resumes fuel supply from the cylinder in the compression stroke, if it is determined that it is impossible to resume the fuel supply from the cylinder in the intake stroke at the time the determination of the transition, the Resuming cylinder switching means for performing the intake stroke injection to the cylinder after the cylinder in the intake stroke at the time of transition determination ;
Provided,
The supply amount setting means is applied only to fuel supply performed by the restart cylinder switching means, and a value correlated with the pressure value in the cylinder is based on the output of the pressure correlation value detection means during the intake stroke and the exhaust stroke. The pressure value in the cylinder is calculated by correcting with the calculated conversion coefficient, the intake air amount into the cylinder is calculated from the pressure value in the cylinder, and the basic fuel supply amount is calculated according to the intake air amount. A control apparatus for an in-cylinder direct injection engine characterized by being determined. Supply determination means for determining whether to supply or stop supplying fuel;
A supply amount setting means for setting a fuel supply amount based on operating conditions at the time of fuel supply;
In-cylinder direct supply means for directly injecting and supplying fuel into the cylinder based on the output of the supply amount setting means, and performing intake stroke injection after resumption of fuel supply from the supply stop state by the supply determining means ;
Ignition timing setting means for setting an ignition timing based on operating conditions at the time of fuel supply;
Ignition means for igniting based on the output of the ignition timing setting means;
In the in-cylinder direct injection engine control device having
When the fuel is first supplied when the supply determining unit determines the transition from the supply stop state to the supply state, the set supply amount is set based on the outputs of the supply amount setting unit and the ignition timing setting unit. Resuming cylinder determining means for determining whether it is possible to supply to the cylinder in the compression stroke at the time of determining the transition by the ignition timing;
If it is determined to be a resumes fuel supply from the cylinder in the compression stroke, if it is determined that it is impossible to resume the fuel supply from the cylinder in the intake stroke at the time the determination of the transition, the Resuming cylinder switching means for performing the intake stroke injection in the cylinder after the cylinder in the intake stroke at the time of determination of transition ,
The supply amount setting means calculates the intake air amount into the cylinder based on the output of the in-cylinder pressure detection means for detecting the pressure value in the cylinder, and determines the basic fuel supply amount according to the intake air amount. On the other hand, the predetermined number of combustions after restarting the fuel supply is calculated based on the intake air amount that is transiently calculated from the pressure value in the cylinder, and after the predetermined number of times, the intake air amount to the engine is calculated. A control apparatus for an in-cylinder direct injection engine, comprising: a calculation method switching means for calculating a fuel supply amount based on an output of an intake air amount detection means for direct detection. Supply determination means for determining whether to supply or stop supplying fuel;
A supply amount setting means for setting a fuel supply amount based on operating conditions at the time of fuel supply;
In-cylinder direct supply means for directly injecting and supplying fuel into the cylinder based on the output of the supply amount setting means, and performing intake stroke injection after resumption of fuel supply from the supply stop state by the supply determining means ;
Ignition timing setting means for setting an ignition timing based on operating conditions at the time of fuel supply;
Ignition means for igniting based on the output of the ignition timing setting means;
In the in-cylinder direct injection engine control device having
When the fuel is first supplied when the supply determining unit determines the transition from the supply stop state to the supply state, the set supply amount is set based on the outputs of the supply amount setting unit and the ignition timing setting unit. Resuming cylinder determining means for determining whether it is possible to supply to the cylinder in the compression stroke at the time of determining the transition by the ignition timing;
If it is determined to be a resumes fuel supply from the cylinder in the compression stroke, if it is determined that it is impossible to resume the fuel supply from the cylinder in the intake stroke at the time the determination of the transition, the Resuming cylinder switching means for performing the intake stroke injection in the cylinder after the cylinder in the intake stroke at the time of determination of transition ,
The supply amount setting means calculates the pressure value in the cylinder based on the output of the pressure correlation value detection means for detecting a value correlated with the pressure value in the cylinder, and further calculates the pressure value in the cylinder from the pressure value in the cylinder. The basic fuel supply amount is determined in accordance with the intake air amount, while the predetermined number of combustions after the restart of the fuel supply is transiently calculated from the pressure value in the cylinder And a calculation method switching means for calculating the fuel supply amount based on the output of the intake air amount detection means for directly detecting the intake air amount to the engine after a predetermined number of times. In-cylinder direct injection engine control device.   The generated torque for each combustion is calculated from the in-cylinder pressure value for a predetermined number of times after the fuel supply is resumed, and at least one of the supply amount correction coefficient and the ignition timing correction value for the next combustion time is calculated based on the generated torque. The control device for a direct injection type in-cylinder engine according to any one of claims 1 to 6, further comprising correction amount correction means for further correcting the above.   The supply amount setting means corresponds to a basic fuel supply amount determined based on the intake air amount during a predetermined number of combustions after the fuel supply resumption is determined by the supply determination unit so as to control the generated torque. 8. The control device for a direct injection type in-cylinder engine according to claim 1, wherein the fuel supply amount is set by correcting with the predetermined supply amount correction coefficient.   The ignition timing setting means sets a basic ignition timing determined based on operating conditions during a predetermined number of times of combustion after the fuel supply resumption is determined by the supply determination means to a predetermined number corresponding to the number of combustions so as to control the generated torque. The in-cylinder direct injection type engine control device according to any one of claims 1 to 8, wherein the ignition timing is set by correcting with an ignition timing correction value.

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