JPH09177582A - Control device for cylinder direct injection type spark ignition engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the response in restart of fuel supply and prevent the deterioration in operability. SOLUTION: When a restart of fuel supply is judged by a supply judging means A for judging the supply/supply stop of fuel, fuel supply quantity and ignition timing are set on the basis of operating conditions by a supply quantity setting means B and an ignition timing setting means D. From the fuel supply quantity and the ignition timing, whether the fuel supply by cylinder direct injection type to a cylinder in compressing stroke is in time or not is judged by a restarted cylinder judging means F. On the basis of this judgment, the cylinder to restart fuel supply at first is selected from the cylinders in compression stroke and the cylinders in intake stroke, and switched. At least one of the fuel supply quantity and the ignition timing is corrected according to the combustion frequency from supply start to regulate the generating torque.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a controller for an engine of an automobile or the like, and more particularly to a controller for a direct injection type spark ignition engine having a direct injection injector for directly injecting fuel into a cylinder.

[0002]

2. Description of the Related Art Conventionally known in-cylinder direct injection type engines are equipped with direct injection injectors for directly supplying fuel into cylinders, so that it is possible in principle to supply fuel even in the compression stroke in which the intake valve is not open. Is. However,
Taking into consideration the homogenization of the air-fuel mixture due to the flow of intake air and the securing of a time for the injected fuel to be sufficiently atomized, fuel may be supplied in the intake stroke following the conventional intake port injection type engine. Many. This method also eliminates the wall flow due to direct injection, so that the advantages of the direct injection type engine, such as improved emission performance, can be fully utilized.

In such an engine, when the throttle is fully closed when the engine speed is relatively high, it is determined that the driver intends or allows deceleration, and the fuel is supplied. Stop to generate deceleration, and
We are trying to improve fuel efficiency. Then, when a predetermined condition is satisfied such as when the throttle is opened, it is determined that the intention of deceleration is interrupted, and the fuel supply is restarted. Further, even when the engine speed decreases, the fuel supply is restarted in order to prevent an unexpected engine stop (engine stall).

When the fuel supply is restarted, a sudden change in torque gives a driver discomfort and adversely affects drivability. Therefore, the torque generated is retarded by retarding the ignition timing, or the torque is reduced from the prior art. Torque operation is performed by sequentially increasing the number of cylinders for restarting fuel injection as described in 196149.

[0005]

However, in such a conventional control apparatus for a direct injection type direct injection engine, the fuel supply is restarted from the cylinder which is in the intake stroke after the fuel supply is judged to be restarted. It is unavoidable that there will be some time delay from when the fuel supply is restarted to when the torque is actually generated.

FIG. 20 is a diagram showing the in-cylinder pressure and the generated torque corresponding to the combustion cycle when the fuel supply of the 4-cylinder in-cylinder direct injection gasoline engine is restarted. Now, referring to FIG. 20, let us consider a case where fuel supply is restarted when the throttle is opened from the state where fuel supply is stopped. When the throttle is opened at timing t ₀ in the figure, the intake stroke injection engine has already entered the intake stroke #.
The fuel supply to the 1st cylinder is not completely in time, and the complete fuel supply is finally resumed from the # 3 cylinder which goes through the intake stroke, so that the in-cylinder pressure and the generated torque of the # 1 cylinder are broken lines in FIG. As a result, there was a problem that the response was poor.

On the other hand, if the torque operation of retarding the ignition timing and sequentially increasing the number of cylinders for restarting the injection is eliminated or alleviated in order to improve the response, there is a problem that the drivability deteriorates. Also, since the speed of rotation speed reduction varies depending on the operating conditions, it is most likely that engine stall will occur when fuel supply is restarted due to the decrease in rotation speed (when the rotation speed suddenly decreases). However, in order to continue the operation, it is necessary to set the rotation speed for restarting the fuel supply to the safe side in consideration of the delay in torque generation. However, with such a setting, under other conditions, there is a problem that the margin until the engine stall becomes too large, and the improvement in fuel consumption cannot be achieved sufficiently.

In view of the above conventional problems, the present invention achieves both improved response and prevention of deterioration of drivability,
Furthermore, it aims at improving fuel economy and stalling resistance.

[0009]

Therefore, in the present invention, the characteristic of the direct injection system that the fuel injection is not stopped for the cylinder during the intake stroke when the throttle is opened but the compression stroke injection can be performed is utilized. Then, fuel is supplied between the intake stroke and the ignition of the compression stroke, and the intake stroke injection is performed in the same manner as in the conventional cylinders.

That is, in the invention according to claim 1, FIG.
As shown in FIG. 5, supply determining means A for determining whether to supply or stop supplying the fuel, and supply amount setting means B for setting the fuel supply amount based on the operating condition when the fuel is supplied, An in-cylinder direct supply means C for directly injecting fuel into the cylinder based on the output of the supply amount setting means; an ignition timing setting means D for setting an ignition timing based on an operating condition when the fuel is supplied; In a control device for a direct injection type cylinder engine having ignition means E for igniting on the basis of an output of an ignition timing setting means, fuel is first supplied when the supply judging means judges a transition from a supply stopped state to a supply state. At this time, based on the outputs of the supply amount setting means and the ignition timing setting means, the set supply amount is supplied to the cylinder in the compression stroke at the time of the determination of the transition by the set ignition timing. Resumption cylinder determination means F for determining whether or not is possible, and if it is determined to be possible, fuel supply is resumed from the cylinder in the compression stroke, and if it is determined to be impossible, the transition Resuming cylinder switching means G for restarting fuel supply from the cylinder in the intake stroke at the time of determination is provided.

Further, in the invention according to claim 2, the supply amount setting means determines the predetermined number of combustions after the fuel supply restart determination by the supply determining means is the basic fuel supply amount determined based on the intake air amount. The fuel supply amount is corrected by a predetermined supply amount correction coefficient corresponding to the number of combustions so as to control the generated torque. Also, in the invention according to claim 3, the ignition timing setting means controls the generated torque, the basic ignition timing determined based on the operating condition, the predetermined number of combustions after the fuel supply restart determination by the supply determination means. As described above, the ignition timing is set by being corrected by a predetermined ignition timing correction value corresponding to the number of combustions.

Further, in the invention according to claim 4, the supply amount setting means calculates the intake air amount into the cylinder based on the output of the in-cylinder pressure detecting means for detecting the pressure value in the cylinder, It is characterized in that the basic fuel supply amount is determined according to the intake air amount. Further, in the invention according to claim 5, 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 having a correlation with the pressure value in the cylinder. The intake air amount into the cylinder is calculated from the pressure value in the cylinder, and the basic fuel supply amount is determined according to the intake air amount.

When the fuel supply is restarted as described above, in terms of the above-mentioned "securing the time for homogenizing the air-fuel mixture by the flow of the intake air and sufficiently atomizing the injected fuel". Although it is slightly inferior to an engine that performs only intake stroke injection, the state of in-cylinder pressure and generated torque is as shown by the solid line in Fig. 20. It becomes possible to improve.

Further, in this case, the fuel is supplied soon after the throttle is opened. Therefore, when the air flow meter is used to measure the intake air amount for calculating the fuel supply amount, the response may not catch up. But in that case,
The intake air amount may be approximately calculated from the output of the in-cylinder pressure sensor mounted in each cylinder, and the fuel supply amount may be calculated based on this.

Therefore, in the invention according to claim 6, the supply amount setting means transiently supplies the fuel based on the intake air amount calculated from the pressure value in the cylinder for a predetermined number of combustions after restart of the fuel supply. The present invention is characterized by including a calculation method switching unit that calculates the amount of fuel and calculates the fuel supply amount based on the output of the intake air amount detecting unit that directly detects the amount of intake air to the engine after a predetermined number of times.

Further, in the invention according to claim 7, the predetermined number of combustions after the fuel supply is restarted is calculated by calculating the generated torque for each combustion from the in-cylinder pressure value, and based on the generated torque, the supply amount of the next combustion is calculated. It is characterized by further comprising a correction amount correction means for further correcting at least one of the correction coefficient and the ignition timing correction value.

[0017]

BEST MODE FOR CARRYING OUT 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 a cylinder direct injection engine to which the present invention is applied. In the engine 1 of FIG. 2, intake is performed through the throttle valve 2, the surge tank 3, the intake manifold 4, and the intake valve 5, and the fuel is directly supplied to the combustion chamber 7 from the direct injection injector 6 as the in-cylinder direct supply means. To be done.

The spark plug 8 as the ignition means is
An electrode for ignition is provided so as to face the inside of the combustion chamber 7. As a 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 amount of intake air, and a throttle valve 2
Idle switch (not shown) that is turned on at the fully closed position of
There is a crank angle sensor (not shown) that measures the crank position of the engine 1. The crank angle sensor is directly or indirectly connected via a gear to a crank shaft or a cam shaft that rotates in conjunction with the crank shaft, and calculates the crank position (crank angle) and the rotation speed of the engine 1.

In order to detect the combustion state, an in-cylinder pressure sensor 10 as an in-cylinder pressure detecting means is mounted. The air-fuel ratio is controlled by adjusting the fuel injection amount by the direct injection injector 6. In addition to this, a water temperature sensor 11 that measures the cooling water temperature of the engine and O ₂ that measures the oxygen concentration in the exhaust gas
The sensor 12 and the like are provided. Input / output of information to / from the outside and various calculations are realized by a circuit centered on the microcomputer shown in FIG. Various sensors such as the air flow meter 9 described above are connected to the input port 13, and the information thereof is input. A / D converter 14
Then, of the signals obtained from various sensors via the input port 13, analog signals are A / D converted so that they can be handled by a computer. Then, 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 / controlling an external device.

The ROM 17 previously stores a control program, various data, etc., which will be described later, and the RAM 18 temporarily stores information during execution of the program. Next, a first embodiment of the present invention will be described. FIG. 4 is a routine for determining whether to supply or stop the fuel, which is executed every predetermined time.

Step 1 (denoted as S1 in the figure, the same applies hereinafter)
Then, it is determined from the fuel supply stop flag Fc whether the fuel is being supplied. When fuel is supplied (Fc = 0),
In Step 2, determine whether the idle switch is ON,
In step 3, it is determined whether the engine speed N is equal to or higher than a predetermined fuel supply stop speed Nfc.

When the idle switch is ON (throttle valve is fully closed) and the engine speed N is a predetermined fuel supply stop speed Nfc in the determination of step 2 and step 3.
In the above case, the routine proceeds to step 4, where the fuel supply stop flag Fc is set to 1 and the fuel supply is stopped. In addition, in the cases other than the above by the judgment of step 2 and step 3,
Continue to supply fuel.

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, and in step 6, the engine speed is changed. It is determined whether or not the number N is lower than a predetermined fuel supply restart speed Nrc. Whether the idle switch is turned off (in other words, the accelerator pedal is depressed) or the engine speed N is a predetermined fuel supply restart speed N depending on the determinations in step 5 and step 6
If it is less than rc, in step 7, the fuel supply stop flag Fc is set to 0 and the fuel supply is restarted.

The above routine corresponds to supply determining means. FIG. 5 is a routine for setting the fuel supply amount and the ignition timing when the fuel supply is resumed from the state where the fuel supply is stopped, and is executed when the fuel supply is resumed. First, at step 11, a restart flag Frec = 1 indicating that the fuel supply restart procedure is in progress is set.

Then, in step 12, the initial value n is substituted into the counter C. This n is a constant that determines how many combustions are required to smoothly transition from the resumption of fuel supply to a steady operation, and may be a different value for each operating condition or a constant value regardless of the operating condition. In step 13, the cylinder a which is in the compression stroke when the fuel supply is restarted is determined.
The basic fuel supply amount Ti of is calculated.

Here, FIG. 6 is a flow chart showing a concrete 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, and in step 32, the cylinder intake air amount Tp of the cylinder is calculated from the read cylinder pressure. Then, in step 33, the basic fuel supply amount Ti is calculated based on Tp calculated in the previous stage, and the process is returned to the flow of FIG. The steps 31 to 33 correspond to the supply amount setting means.

In step 14 of FIG. 5, the basic fuel supply amount Ti calculated in the preceding stage is multiplied by the supply amount correction coefficient Lean (C) in order to prevent deterioration of drivability at the time of restarting the fuel supply, and the corrected fuel supply is performed. The quantity Tiadj = Ti * Lean (C). Here, Lean (C) is determined by the value of the counter C, for example, 1 as the value of the counter C decreases as shown in FIG.
Is a table value approaching.

In the following step 15, the basic ignition timing Advmap at that time is read from the map based on the operating conditions such as the intake air amount Tp calculated in step 13, the rotational speed N or the cylinder intake air-fuel ratio. Then, in step 16, it is judged 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 the reopening cylinder determination means.

If it is determined in step 16 that the fuel supply can be completed, in step 17 the fuel supply amount Tiout is set to Tiadj
Is substituted, and in step 18, Advmap is substituted for the ignition timing Adv. Then, in step 19, the counter C is decremented by 1.
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 process proceeds to step 20.

In step 20, it is judged whether the intake valve is in the intake stroke when the fuel supply is judged to be restarted, and the intake valve of the cylinder b, which is to undergo the compression stroke next to the cylinder a, is closed. If the intake valve of the cylinder b is not closed, wait 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 21.
This step 21 uses steps 31 to 33 shown in FIG. 6 similarly to step 13.

Then, in step 22, the obtained basic fuel supply amount Ti is multiplied by the supply amount correction coefficient Lean (C),
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, based on the results of step 22 and step 23, the fuel supply amount Tiout = Tiadj is set in step 24, the ignition timing Adv = Advmap is set in step 25, and the value of the counter C is decremented by 1 in step 26.

Steps 17 to 26 correspond to restart cylinder switching means. Here, waiting time until the intake valve is closed in step 20 is because when the intake air amount is calculated from the cylinder pressure, it is more accurate if the valve is closed and the cylinder becomes a closed space. Therefore, when the cylinder intake air amount is obtained by the air flow meter 9, this waiting time is not necessary.

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 restarted becomes n times. This routine is started by the reference signal from the crank angle sensor (every 180 ° CA in the case of four cylinders). First, in step 41, the supply restart flag Fre
c is checked, and when Frec = 1, it is determined that the fuel supply procedure is in progress, and in the following step 42, it is determined whether or not the counter C is 0 or less (whether or not the fuel supply resumption procedure has been completed n times). To check.

When the counter C is not 0 or less 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 the measured value 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, Ti is multiplied by the supply amount correction coefficient Lean (C) to obtain the fuel supply amount Tiout = Ti x Lean (C). .

In step 47, the intake air amount T at that time is calculated.
The basic ignition timing Advmap corresponding to the operating conditions such as p, rotational speed N, air-fuel ratio, etc. is read from a predetermined ignition timing map, and Advmap is substituted for the ignition timing Adv in step 48, and the processing is ended. If the counter C is 0 or less at step 42, it is determined that the fuel supply resumption procedure is completed, and at step 49, the supply resumption flag Frec is set to 0 so that the following normal combustion conditions are satisfied.

That is, in step 50, the cylinder intake air amount Tp is calculated from the history of the measured values 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 for the fuel supply amount Tiout in step 52, the ignition timing Adv is set in steps 47 and 48, and the process ends. If the supply resumption flag Frec = 0 in step 41, the fuel supply resumption procedure has been completed, so steps 50 to 52 and steps 47 to 48 are similarly executed and the process is completed.

Here, it is assumed that the actual fuel supply and ignition based on the set values are executed by an upper interrupt procedure (not shown), and this is the same in the following embodiments. An example of the in-cylinder pressure of each cylinder and the generated torque of the four-cylinder direct injection engine using the processing described so far is shown in FIG.
And FIG. The solid line in FIG. 9 indicates the case where the fuel supply can be resumed from the cylinder a that was in the compression stroke when the fuel supply restart was determined (fuel supply restart from the # 2 cylinder).

The solid line in FIG. 10 shows the case where the fuel supply is restarted from the cylinder b which was in the intake stroke when the fuel supply restart was judged (fuel supply restarted from the # 1 cylinder). In either case, the fuel supply can be restarted so that the torque is generated with good response and smoothly as compared with the case where the fuel supply is performed only by the conventional intake stroke (broken line in the figure).

In the above description, when the cylinder intake air amount Tp is calculated from the cylinder pressure by the procedure shown in FIG. 6, the cylinder pressure sensor can detect the absolute pressure value. There are some that can detect related values 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 premised that the in-cylinder pressure sensor 10 as the pressure correlation value detecting means detects a value proportional to the pressure.

FIG. 12 is a diagram showing the output of the in-cylinder pressure sensor corresponding to the crank angle. Referring to FIG. 11 and FIG. 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 in the exhaust stroke (substantially equal to the exhaust pressure)
Is almost known for each operating condition, and when the auxiliary air is corrected so that the in-cylinder pressure during the intake stroke becomes a certain level Pin when the fuel supply is stopped, in step 63 the pressure correlation value is absolute as shown in the following equation. A conversion coefficient K for converting into pressure is calculated. K = (Pex-Pin) / (V2-V1) In step 64, the output V of the in-cylinder pressure sensor is read, and in step 65, the pressure correlation value read by the conversion coefficient K is converted into an absolute pressure value as in the following equation.

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 the step
At 67, the basic fuel supply amount Ti is calculated based on Tp.

In the above-described first embodiment, after the fuel supply is restarted, the fuel supply amount is corrected for a predetermined number of combustions to recover the torque smoothly. Alternatively, the ignition timing may be corrected. Next, a second embodiment using the correction of the ignition timing will be described. FIG. 13 is a flowchart showing a procedure for correcting the ignition timing when the fuel supply is restarted.

First, when the restart of the fuel supply is judged by the routine of FIG. 2, the restart flag Frec indicating that the fuel supply restart procedure is in progress is set to 1 in step 71, and in the following step 72, the initial value is set in the counter C. Substitute n. Next, at step 73, the basic fuel supply amount Ti is calculated according to the processing of FIG. 6 or 11.

Then, in step 74, the intake air amount Tp
Then, the basic ignition timing Advmap at that time is read from a predetermined map based on the operating conditions such as the rotational speed N. In the following step 75, the ignition timing correction value Ret is changed from the basic ignition timing Advmap in order to prevent deterioration of drivability when the fuel supply is restarted.
(C) is subtracted (retarded), and Advadj = Advmap −
Ret (C). Here, Ret (C) is, for example, as shown in FIG.
The table value decreases as the value of the counter C decreases as shown in FIG.

In step 76, it is judged whether or not it is possible to finish the injection of the basic fuel supply amount Ti into the cylinder a during the compression stroke by the corrected ignition timing. When it is determined that the fuel supply can be completed in step 76, Ti is substituted for the fuel supply amount Tiout in step 77, and the ignition timing Adv is set to A in step 78.
Substituting dvadj, the value of counter C is set to 1 in step 79.
cut back.

When it is judged 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, when it is judged that the fuel supply is restarted. . It is determined whether or not the intake valve of the cylinder b during the air stroke is closed. If the intake valve is not closed, wait until the intake valve is closed. If the intake valve is closed, the basic fuel supply amount Ti for cylinder b is calculated in step 81 in the same manner as in step 73.

In step 82, the basic ignition timing Advmap is read from a predetermined map in the same manner as in step 74, and correction is performed by Ret (C) in step 83, and Advadj = Advma
p − Ret (C). Then, in step 84, the fuel supply amount Tiout of the cylinder b in the intake stroke is Ti, and in step 85 the ignition timing Advad is retard corrected to the ignition timing Adv.
Substituting j, the value of the counter C is decremented by 1 in step 86, and the process ends.

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 combustions after the fuel supply is restarted becomes n times. This routine uses the reference signal from the crank angle sensor (1
Every 80 ° CA). First, in step 91, the value of the supply resumption flag Frec is checked, and the flag is set to 1
If it is, it is determined that the fuel supply procedure is in progress, and in the following step 92, it is checked whether or not the counter C is 0 or less (whether or not the fuel supply resumption procedure has been completed n times).

If the counter is not 0 or less 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 the measured values of the air flow meter 9 in step 94. In step 95, 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, etc. at that time is read from a predetermined ignition timing map, and in the following step 96, retard corrected Advmap-
Substitute Ret (C) for ignition timing Adv.

In step 97, T calculated in step 94
The basic fuel supply amount Ti is calculated based on p, and step 98
Then, Ti is substituted into the fuel supply amount Tiout, and the process is ended. When the counter C is 1 or less at step 92, it is determined that the fuel supply resumption procedure is completed, and at step 99, the supply resumption flag Frec is set to 0 so that the following normal combustion conditions are satisfied.

That is, in step 100, the cylinder intake air amount Tp is calculated from the history of the measured values of the air flow meter 9, and in step 101 the basic ignition timing Advma is calculated based on Tp.
Read p from the given ignition timing map. Step 102
Then, the ignition timing Adv is adjusted without correcting the basic ignition timing Advmap.
To the fuel supply amount Tiout in steps 97 and 98.
Substitute i and exit.

In step 91, the supply restart flag Frec is set.
If is not set, the procedure for resuming fuel supply has been completed. Therefore, the procedures of steps 100 to 102 and steps 97 to 98 are similarly performed and completed. Also in the case where the second embodiment is applied, when the fuel supply is restarted from the cylinder a which was in the compression stroke when the fuel supply restart is judged, the in-cylinder pressure and the generated torque are shown in FIG. 9 is the solid line (fuel supply is restarted from the # 2 cylinder), and when fuel supply is restarted from the cylinder b during the intake stroke, the fuel supply is restarted. (Fuel supply is restarted from the # 1 cylinder).

In any case, as in the first embodiment,
Compared to the conventional case where fuel is supplied only in the intake stroke (broken line in the figure), the fuel supply can be restarted so that the response is good and the torque is smoothly generated.
Next, a third embodiment will be described. This uses both the torque correction by the correction of the fuel supply amount used in the first embodiment and the torque correction by the correction of the ignition timing used in the second embodiment, and is shown in FIGS. 16 and 17. It is executed by the procedure described below.

FIG. 16 is a flow chart showing a procedure for correcting both the fuel supply amount and the ignition timing when the fuel supply is restarted. In steps 111 to 116, the corrected fuel supply amount Tiadj (= Ti x Lean corrected by the supply amount correction coefficient Lean (C) is used as in the first and second embodiments.
(C)) and the corrected ignition timing Advadj (= Advmap-Ret (C)) corrected by the ignition timing correction value Ret (C).

In the following step 117, the cylinder a during the compression stroke
If it is determined that the fuel supply can be restarted from step 118 and step 119, the fuel supply amount Tiout is substituted with Tiadj and the ignition timing Adv is substituted with Advadj, and the counter C is decremented by one. . If it is determined in step 117 that the fuel supply from the cylinder a during the compression stroke cannot be restarted, or if the processing up to step 120 is completed, the fuel supply is performed in steps 121 to 125. When the valve of cylinder B that was in the intake stroke is closed when it is determined that the fuel supply amount Tiout (=
Ti * Lean (C)) and ignition timing Adv (= Advmap-Ret
(C)) based on the same formula, and step 126
Then, the value of the counter C is decremented by 1 and the process ends.

FIG. 17 is a routine for setting the fuel supply amount and the ignition timing for each cylinder until the cumulative number of combustions after the fuel supply is restarted becomes n after the routine of FIG. 16 is completed. Here again, as in the first and second embodiments, in step 131, the supply resumption flag Frec is checked, and when the flag is 1, it is determined that the fuel supply procedure is in progress,
In the following step 132, it is checked whether the counter C is 0 or less.

If the counter is not 0 or less in step 132, the counter is decremented by 1 in step 133, and step 13
At 4, the cylinder intake air amount Tp is calculated from the history of the measured values of the air flow meter 9. And steps 135 to 13
In step 8, the lean-corrected fuel supply amount Tiout (= Ti * Lean (C)) and the retard-corrected ignition timing Adv (= Advmap-Ret (C)) are set during the fuel supply restart procedure, and the process ends.

In step 131, the supply restart flag Fre is set.
If c is 0, and the counter C is 0 in step 132.
In the following cases, since the fuel supply resumption procedure has been completed, the fuel supply amount Tiout (= Ti) and the ignition timing Adv (= Advmap) under the normal conditions are followed in the procedures of steps 140 to 144.
Set and to finish. In this embodiment, the same counter C is used for both the fuel supply amount correction and the ignition timing correction, and the number of corrections is the same n times. However, these are separate counters C1 and C2, and the number of corrections is n1. And n2, the number of times the fuel supply amount is corrected and the number of times the ignition timing is corrected may be different.

Next, a fourth embodiment will be described. In the first to third embodiments, up to the cylinder intake air amount of the cylinder b during the intake stroke when the fuel supply restart is determined is calculated from the output of the in-cylinder pressure sensor 10 (after restarting 1 to
Two combustion cycles), and the cylinder intake air amount of the subsequent cylinder is calculated from the history of the measured values of the air flow meter 9. However, when there is a large time delay until the air flow meter 9 can detect an accurate intake air amount, the cylinder pressure sensor is used for a predetermined period corresponding to the time delay.
The cylinder intake air amount may be calculated based on the detected value of 10, and then the cylinder intake air amount calculation may be performed based on the detected value of the air flow meter 9.

FIG. 18 is a routine showing a procedure for switching between the calculation of the cylinder intake air amount based on the detected value of the in-cylinder pressure sensor 10 and the calculation of the cylinder intake air amount based on the history of the measured values of the air flow meter 9. For example, in the case of the first embodiment, this routine can be used instead of step 44 and step 50 in FIG. When this routine is used in the first embodiment, at the same time as setting the counter C in step 12 of FIG. 5, an initial value Mn is set in the down counter M which is decremented for each combustion when the fuel supply is restarted. Then, in step 151, it is checked whether or not the counter M is 0 or less (whether the cylinder intake air amount calculation period by the cylinder pressure sensor has ended Mn times).

If the counter M is not less than 0, step
At 152, the cylinder intake air amount Tp is calculated based on the detection value of the in-cylinder pressure sensor 10, and at 153, the counter M is decremented by 1, and the process is ended. When the counter M becomes 0 or less in step 151, the cylinder intake air amount is calculated based on the history of the measured values of the air flow meter 9 in step 154, and the process ends.

The above routine corresponds to the arithmetic 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.

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 when the fuel supply is restarted, the supply amount correction coefficient L which is a predetermined table value.
The ean (C) and the ignition timing correction value Ret (C) were used. These are used to obtain the generated torque for each cycle from the output of the in-cylinder pressure sensor 10 mounted in each cylinder, and further calculate the generated torque based on the generated torque. It may be a variable to be corrected.

FIG. 19 shows an example of a routine for calculating the generated torque (indicated average effective pressure) for each cycle from the in-cylinder pressure value for every 4 ° CA, which is executed for each exhaust top dead center of each cylinder. First, in step 161, the counter S and the integral value P are cleared. Next, in step 162, the 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 counter S from the map.

In step 164, Pcyl read in step 162 and the map value dV read in step 163 are read.
Calculate the product of (S) and dP = Pcyl × dV (S).
In step 165, dP is added to the previous integrated value P by the formula P = P + dP to obtain a new integrated value P. Then, in step 166, the value of the counter S is incremented by 1.

In step 167, S> 180 (720 ° CA
If it is not satisfied, the routine proceeds to step 168, waits for the crank angle to advance by 4 ° CA, and then returns to step 162. S> 18 in step 167
If 0 is satisfied, in step 169, the indicated mean effective pressure Pi is calculated from the integral value P and the stroke volume Vs by the formula Pi = P / Vs.

In step 170, the indicated mean effective pressure Pi
The generated torque Ui is calculated from the above, and in step 171, the generated torque Ui is compared with the target value U of the generated torque when the fuel supply is restarted, which has been previously calculated for each operating condition. If there is no difference between the generated torque Ui and the target torque U, the processing is terminated as it is, and if there is a difference, in step 172, the correction coefficient Lean (C) and / or the correction value R is set in the direction in which the difference is eliminated.
Correct et (C) and end.

The above routine corresponds to the correction amount correction means. By doing so, the torque generated when the fuel supply is restarted can be made to be a desired value even if the operating environment changes or the characteristics of the injector change, such as changes in hardware over time.

[0069]

As described above, according to the present invention, when it is judged that good combustion can be realized in the cylinder in the compression stroke at the time when it is judged that the fuel supply is restarted, By restarting the fuel supply from the cylinder during the compression stroke, and otherwise from the cylinder during the intake stroke, the fuel supply is restarted at a faster cycle than in the case of conventional port injection, and the predetermined combustion cycle after restarting the fuel supply By performing torque control by correcting the air-fuel ratio and the ignition timing, it is possible to improve response and prevent deterioration of drivability, and improve engine stalling resistance.

That is, according to the invention of claim 1,
When restarting the fuel supply from the state where the fuel supply is stopped in the direct injection type engine, the fuel supply can be restarted from the cylinder under the optimum condition depending on the timing at which the fuel supply is restarted. As a result, there is an effect that the response can be improved and the fuel consumption can be improved by reducing the rotation speed for restarting the fuel supply.

According to the second aspect of the invention, when the fuel supply is restarted from the state where the fuel supply is stopped, by controlling the amount of fuel supplied and adjusting the generated torque, There is an effect that it is possible to reduce the deterioration of drivability. According to the third aspect of the invention, when the fuel supply is restarted from the state where the fuel supply is stopped, the ignition timing is controlled and the generated torque is adjusted, so that the drivability at the time of restarting the fuel supply is deteriorated. There is an effect that it can be reduced.

Further, according to the fourth aspect of the present invention, even if the response of the intake air amount sensor is not high, the intake air amount when the fuel supply is restarted can be quickly obtained, and the optimum fuel supply amount can be obtained. The effect is that it can be set. Further, according to the invention of claim 5, even when the absolute pressure value in the cylinder cannot be detected, the intake air amount at the time of restarting the fuel supply can be quickly obtained, and the optimum fuel supply amount can be set. The effect is that you can do it.

According to the sixth aspect of the invention, when the intake air amount immediately after the fuel supply is restarted is directly detected, even if the response of the detected value is not high, the predetermined period after the fuel supply is restarted. Has an effect that the required fuel amount can be quickly and accurately obtained by approximately detecting the intake air amount from the cylinder pressure value. Further, according to the invention of claim 7, there is an effect that the generated torque after the fuel supply is restarted can be accurately adjusted and more desirable characteristics can be obtained.

[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 performing a fuel supply / stop determination executed at predetermined time intervals.

FIG. 5 is a flowchart for setting a fuel supply restart cylinder, a fuel supply amount, an ignition timing, and a fuel supply amount correction method.

FIG. 6 is a flowchart showing a specific process for calculating the basic fuel supply amount Ti.

FIG. 7: Supply amount correction coefficient Lean based on the value of counter C
The figure which shows an example of the table which determines (C)

FIG. 8 is a flowchart for setting the fuel supply amount and the ignition timing for each cylinder up to the cumulative number of combustions n after the fuel supply is restarted.

FIG. 9 is a diagram showing in-cylinder pressure and generated torque when fuel supply is restarted from a cylinder that was in a compression stroke at the time of fuel supply restart determination.

FIG. 10 is a diagram showing in-cylinder pressure and generated torque when fuel supply is restarted from the cylinder that was in the intake stroke at the time of fuel supply restart 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 fuel supply restart cylinder, a fuel supply amount, an ignition timing, and an ignition timing correction method.

FIG. 14 shows an ignition timing correction value Ret based on the value of the counter C.
The figure which shows an example of the table which determines (C)

FIG. 15 is a flowchart for setting the fuel supply amount and the ignition timing for each cylinder up to the cumulative number of combustions n after the fuel supply is restarted.

FIG. 16 is a flowchart showing a procedure for correcting both the fuel supply amount and the ignition timing when the fuel supply is restarted.

FIG. 17 is a flowchart for setting the fuel supply amount and the ignition timing for each cylinder up to the cumulative combustion number n after the fuel supply is restarted.

FIG. 18 is a flowchart showing a procedure for switching the cylinder intake air amount calculation.

FIG. 19 is a flowchart for calculating the generated torque for each cycle from the in-cylinder pressure value for each 4 ° CA.

FIG. 20 is a diagram showing in-cylinder pressure and generated torque when fuel supply is restarted between the port injection type engine and the direct injection type engine.

[Explanation of symbols]

1 Engine 2 Throttle Valve 3 Surge Tank 4 Intake Manifold 5 Intake Valve 6 Direct Injection Injector 7 Combustion Chamber 8 Spark Plug 9 Air Flow Meter 10 Cylinder Pressure Sensor 11 Water Temperature Sensor 12 O ₂ Sensor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display F02P 5/15 F02P 5/15 F

Claims (7)

[Claims] 1. A supply determining means for determining whether to supply or stop supplying fuel, supply amount setting means for setting a fuel supply amount based on an operating condition at the time of fuel supply, and the supply. An in-cylinder direct supply means for directly injecting fuel into the cylinder based on the output of the amount setting means; an ignition timing setting means for setting an ignition timing based on an operating condition when the fuel is supplied; and an ignition timing setting means In a control device for a direct injection engine in a cylinder having an ignition means for igniting on the basis of the output of, when the fuel is initially supplied when the supply determination means determines the transition from the supply stopped state to the supply state, Based on the outputs of the supply amount setting means and the ignition timing setting means, it is possible to supply the set supply amount to the cylinder in the compression stroke by the set ignition timing when the transition is judged. Resuming cylinder determining means for determining whether or not it is possible to restart the fuel supply from the cylinder in the compression stroke if it is determined to be possible, and intake air at the time of transition determination if it is determined to be impossible. An in-cylinder direct injection engine control device comprising: a restart cylinder switching means for restarting fuel supply from a cylinder in a stroke. 2. The supply amount setting means controls the generated torque of the basic fuel supply amount, which is determined based on the intake air amount, for the predetermined number of combustions after the fuel supply restart determination of the supply determination means. 2. The control apparatus for a direct injection engine for a cylinder according to claim 1, wherein the fuel supply amount is set by being corrected by a predetermined supply amount correction coefficient corresponding to the number of combustions. 3. The ignition timing setting means sets a predetermined number of combustions after the fuel supply is decided to be restarted by the supply determining means, and sets a basic ignition timing determined based on an operating condition so as to control a generated torque. 3. The control device for a direct injection engine for a cylinder according to claim 1, wherein the ignition timing is set by correcting the ignition timing by a predetermined ignition timing correction value corresponding to. 4. The supply amount setting means calculates the intake air amount into the cylinder based on the output of the in-cylinder pressure detecting means for detecting the pressure value in the cylinder, and the basic fuel is calculated according to the intake air amount. The method for determining a supply amount according to claim 1,
The control device for a direct injection engine in a cylinder according to any one of claims 3 to 4. 5. The supply amount setting means calculates the pressure value in the cylinder based on the output of the pressure correlation value detecting means for detecting a value having a correlation with the pressure value in the cylinder, and further, the pressure in the cylinder is calculated. The intake air amount into the cylinder is calculated from the value, and the basic fuel supply amount is determined according to the intake air amount. In-cylinder direct injection engine control device. 6. The supply amount setting means transiently calculates the fuel supply amount based on the intake air amount calculated from the pressure value in the cylinder for a predetermined number of combustions after the fuel supply is restarted, and the predetermined number of times elapses. A cylinder according to claim 4 or 5, further comprising a calculation method switching means for calculating the fuel supply amount based on the output of the intake air amount detecting means for directly detecting the intake air amount to the engine. Internal direct injection engine control device. 7. The predetermined number of combustions after resuming fuel supply is performed by calculating a torque generated for each combustion from the in-cylinder pressure value, and based on the generated torque, a supply amount correction coefficient and an ignition timing correction value for the next combustion time. 7. The control device for a cylinder direct injection engine according to claim 4, further comprising a correction amount correction unit that further corrects at least one of the above.