JPH02181050A - Intake air pressure detecting device for internal combustion engine - Google Patents

Abstract

PURPOSE:To avoid generation of sampling error by judging stationary and transient conditions according to the deviation between the changes in increase direction and decrease direction and changing over selectively an intake air pressure sampling means according to the above judging results. CONSTITUTION:An increase and decrease change detecting means C is provided which detects the changes in increase direction and decrease direction of intake air pressure detected by an intake air pressure detecting means B according to the detecting signals outputted from a crank angle position detecting means A at every constant crank angle position of an engine. According to the deviation between the changes in increase direction and decrease direction, the stationary and transient operation is judged by a judging means D. A sampling means E for transient operation and a sampling means F for stationary operation which differ from each other, set as the final detecting value by sampling intake air pressure are provided, and these means are changed over selectively by the judging means D according to the judging results of the judging means D for intake pressure sampling.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an intake pressure detection device for an internal combustion engine, and more specifically, to an intake pressure detection device for detecting intake pressure for use in setting fuel supply amount, etc. Related to improving the discrimination between steady and transient operation of an engine in an intake pressure detection device configured to set the final detected value by sampling the detection signal from the sensor using different sampling methods during transient operation and steady operation of the engine. .

<Prior art> Conventionally, an intake pressure sensor that detects intake pressure (intake negative pressure) is installed in the intake passage of an engine, and the amount of fuel supplied to the engine is set based on the intake pressure detected by the intake pressure sensor. A fuel supply control device configured to control is known (see Japanese Patent Application Laid-Open No. 150040/1983).

By the way, the intake pressure detected by the sensor picks up pressure pulsations that occur during steady engine operation, so if the instantaneous value of the detected value is used to set and control the fuel supply amount, the actual intake air amount of the engine will be constant. Even if there is, there is a problem in that the amount of fuel supplied increases or decreases with pressure pulsations, causing fluctuations in the air-fuel ratio.

In order to solve the above problems, there have been proposed systems in which the intake pressure detected by a sensor is sampled using various methods and used for setting the fuel supply amount.

Examples of such intake pressure sampling methods include:
The configuration is configured to perform weighted average processing on the intake pressure detection values sampled in time synchronization, and set this weighted average result as the final detected value.During steady operation, past data is given greater weight in the weighted average calculation to dampen pulsation. There is a structure in which the weighting is reduced during transient operation to ensure transient response. In addition, during transient operation, the data sampled with time synchronization is directly set as the final detected value, and during steady operation, the arithmetic mean value (adding all sample values and calculating the number of samples) for each constant crank angle rotation of the data sampled with time synchronization. There is also a method that aims to eliminate the pulsation effect during steady operation and achieve transient response.

<Problems to be Solved by the Invention> However, as described above, in order to avoid the influence of pressure pulsation during steady operation and ensure detection responsiveness during transient operation, it is necessary to The system that switches the sampling method depending on the situation is configured to determine that a transient operating state occurs when a change in throttle valve opening or a change in engine rotational speed occurs.
If the sampling method switching setting becomes inappropriate near the discrimination boundary between steady and transient operation, for example, as shown in Figure 10, steady state discrimination may be made during transient operation and an intake pressure sampling error may occur. Ta.

That is, when determining a change in throttle valve opening or a change in rotation speed, the actually detected rate of change (amount of change) is compared with a predetermined slice level, and the engine is determined based on the magnitude of the actual value with respect to the slice level. Since it is configured to determine whether it is a transient operating state or a steady operating state, variations in the steady/transient discrimination occur when there is a change near the slice level, and this causes variations in the switching of the sampling method. (It was supposed to happen.

In this way, for example, if it is incorrectly determined that steady operation is in progress during a transient operation (see Figure 10), sampling will be performed during the transient operation at the expense of responsiveness in order to avoid the effects of pulsation. Therefore, execution of this incorrect sampling method deteriorates fuel controllability during that time.

However, in setting the slice level, experiments were conducted by actually operating the engine, and the slice level was determined so that in operating conditions where pressure pulsations occur, steady operation is determined and sampling processing is performed to attenuate the pulsations. There was also the problem that the level needed to be finely adjusted and set, which required time for development.

The present invention has been made in view of the above-mentioned problems, and includes an intake pressure detection device configured to sample intake pressure detected values using different methods during transient operation and steady operation of the engine. The purpose is to improve the accuracy of sampling method switching by improving the accuracy of operation discrimination, and to avoid the effects of pressure pulsation during steady operation and ensure responsiveness during transient operation in all operating conditions. shall be.

<Means for Solving the Problems> Therefore, as shown in FIG. 1, the present invention includes an intake pressure detection means provided in the intake passage of the engine to detect the intake pressure, and a detection means for detecting the intake pressure at each constant crank angle position of the engine. a crank angle position detection means for outputting a signal; and an increase/decrease amount of change for detecting an increase direction change amount and a decrease direction change amount of the detected intake pressure, respectively, while the detection signal is output from the crank angle position detection means. a detection means; a steady/transient operation determining means for determining whether the engine is in steady or transient operation based on the deviation between the increasing and decreasing changes detected by the increase/decrease change detecting means; and the intake pressure detecting means. The sampling means for transient operation and the sampling means for steady operation, which are different from each other, are switched and selected according to the above-mentioned steady/transient operation discrimination, and the intake pressure is set as the final detected value. An intake pressure detection device for an internal combustion engine is configured to include sampling switching means for sampling.

Further, instead of the steady/transient operation determining means, a deviation change calculation is performed to calculate the deviation between the increasing direction change amount and the decreasing direction change amount detected by the increase/decrease change amount detection means and the average value of this deviation. and a deviation change dependent steady/transient operation determining means for determining whether the engine is in steady or transient operation based on the deviation calculated by the deviation change calculating means. It is preferable to configure the sampling means to be switched and selected depending on whether the engine is in steady or transient operation.

Furthermore, the deviation calculated by the deviation change calculating means is converted into a value indicating the degree of steady operation or transient operation, and based on this converted value, the steady/transient operation is determined by the deviation change dependent steady/transient operation determining means. A means for converting the degree of steady/transient operation may be provided.

<Operation> In this configuration, the intake pressure detection means is provided in the intake passage of the engine and detects the intake pressure (intake negative pressure) of the engine. Further, the crank angular position detection means outputs a detection signal at each constant crank angular position of the engine.

Here, the increase/decrease change amount detecting means detects the amount of change in the increasing direction and the decreasing direction of the intake pressure detected by the intake pressure detecting means between the detection signals output from the crank angle position detecting means at every fixed crank angle position. The amount of change is detected respectively. That is, the increase/decrease amount detection means detects how much the intake pressure changes in the increase/decrease direction between constant crank angles.

The steady/transient operation determining means determines whether the engine is in a steady operating state or in a transient operating state, based on the deviation between the increasing and decreasing changes in intake pressure between constant crank angles detected as described above. state.

Further, there is provided a sampling means for transient operation and a sampling means for steady operation, which are different from each other and which sample the intake pressure detected by the intake pressure detection means and set it as the final detected value of the intake pressure, The sampling switching means selects and switches between the two sampling means depending on whether steady operation or transient operation of the engine is determined by the steady/transient operation determining means as described above. As a result, when the engine is in steady operation, the intake pressure is sampled by the sampling means for steady operation, and when the engine is in transient operation, the intake pressure is sampled by the sampling means for transient operation, and each sampling means is used to sample the intake pressure. The final detected value of is set.

On the other hand, when a deviation change calculating means and a deviation change dependent steady/transient operation determining means are provided in place of the steady/transient operation determining means, the deviation change calculating means detects the increase/decrease amount detected by the increase/decrease amount detecting means. The deviation change-dependent steady/transient operation determining means calculates the deviation between the increasing direction change amount and the decreasing direction change amount and the average value of these deviations, and the deviation change dependent steady/transient operation discrimination means is based on the deviation calculated by the deviation change calculation means. to determine whether the engine is in steady or transient operation. That is, the deviation change dependent steady/transient operation determining means determines whether the deviation between the increasing amount of change and the decreasing amount of change is
Steady or transient operation of the engine is determined based on whether or not there has been a significant change.

In addition, as mentioned above, when determining whether the engine is in steady or transient operation based on the deviation between the amount of change in the increasing direction and the amount of change in the decreasing direction, and the average value of these deviations, the degree of steady or transient operation is determined. The conversion means converts the deviation calculated by the deviation change calculating means into a value indicating the degree of steady operation or transient operation, and based on this converted value, the steady/transient operation is determined by the deviation change dependent steady/transient operation determining means. Have them make a judgment. The deviation calculated by the deviation change calculation means is a numerical value according to the amount of change in intake pressure, and from this numerical value, it is determined how well the current operating state conforms to the expression representing the engine operating state, such as transient operation. Therefore, the deviation calculated by the deviation change calculation means is converted into a value indicating the degree of steady operation or transient operation, and the steady/transient discrimination with ambiguous boundaries is expressed numerically. I made it possible.

<Example> The present invention will be explained in detail below.

In FIG. 2 showing the system configuration of one embodiment, an internal combustion engine 1 includes an air cleaner 2. Air is taken in through the intake duct 3, the throttle chamber 4, and the intake manifold 5. The air cleaner 2 has an intake air (atmospheric) temperature TA ("C")
) is provided with an intake temperature sensor 6 that detects the temperature. The throttle chamber 4 is provided with a throttle valve 7 that operates in conjunction with an accelerator pedal (not shown), and controls the intake air flow rate Q.
control. The throttle valve 7 has its opening TVO.
A throttle sensor 8 including an idle switch 8A that is turned on at its fully closed position (idle position) is attached along with a potentiometer that detects the position.

The intake manifold 5 downstream of the throttle valve 7 is provided with an intake pressure sensor 9 as an intake pressure detection means for detecting intake pressure (intake negative pressure) PB, and an electromagnetic fuel injection valve 10 is provided for each cylinder. It is being fuel injection valve 10
The valve is driven to open by an injection pulse signal output in synchronization with the ignition timing, for example, from a control unit 11 incorporating a microcomputer, which will be described later, and fuel is fed under pressure from a fuel pump (not shown) and controlled to a predetermined pressure by a pressure regulator. It is injected and supplied into the intake manifold 5. That is, the amount of fuel supplied by the fuel injection valve 10 is controlled by the valve opening driving time of the fuel injection valve 10.

Furthermore, a water temperature sensor 12 for detecting the cooling water temperature Tw in the cooling jacket of the engine 1 is provided, and the exhaust passage 1
An oxygen sensor 14 is provided within the engine 3 to detect the air-fuel ratio of the intake air-fuel mixture by detecting the oxygen concentration in the exhaust gas.

The control unit 11 counts the crank unit angle signal PO8 output from the crank angle sensor 15 as a crank angle position detecting means in synchronization with engine rotation for a certain period of time or at a predetermined crank angle position (for example, ATDC90).
Crank reference angle signal REF (4
In the case of cylinders, the engine rotation speed N is detected by measuring the period (every 180 degrees).

In addition, the Lance Mission (attached to Engine 1)
A vehicle speed sensor 16 that detects the vehicle speed, a neutral sensor 17 that detects the neutral position, and the like are provided, and these signals are input to the control unit 11.

Additionally, an auxiliary air passage 18 bypassing the throttle valve 7
is provided with an electromagnetic idle control valve 19 that controls the idle rotation speed via the amount of auxiliary air.

The control unit 11 calculates the fuel injection amount Ti (pulse width of the injection pulse signal) based on the various detection signals detected as described above, and also controls the fuel injection valve 10 based on the set fuel injection amount Ti. Open drive control. Further, the control unit 11 feedback-controls the idle rotation speed to the target idle rotation speed by controlling the opening degree of the idle control valve 190 during idle operation detected based on the idle switch 8A and the neutral sensor 17.

Next, various calculation processes for fuel control performed by the control unit 11 (including the intake pressure detection device for an internal combustion engine according to the present invention) will be explained according to the routines shown in the flowcharts of FIGS. 3 to 6, respectively.

In this embodiment, an increase/decrease amount detection means, a steady/transient operation discrimination means, and a sampling switching means.

The functions of the sampling means for steady operation, the sampling means for transient operation, the deviation change calculation means, the deviation change dependent steady/transient operation discrimination means, and the steady/transient operation degree conversion means are as shown in FIGS. 5 and 6 above. The software is provided as shown in the flowchart.

The routine shown in the flowchart of FIG.
This is a setting routine. First, step 1 (Sl in the figure)
It's Toshide. The same applies hereafter), the intake pressure PB detected by the intake pressure sensor 9 is based on the final detected value PBAV obtained by performing different sampling processes corresponding to steady and transient operation of the engine 1, respectively, as described later. The volumetric efficiency correction coefficient KPB is determined by searching from a map stored in advance in correspondence with the PBAV.

In the next step 2, in step 11 of the background job (BGJ) shown in the flowchart of FIG. Volumetric efficiency correction minute correction coefficient KFLAT found by search
is multiplied by the basic volumetric efficiency correction coefficient KPB searched and found in step 1 to set the volumetric efficiency correction coefficient KQcyQ.

In the next step 3, the basic fuel injection amount 'rppb is calculated according to the following formula.

Tppb=KcoNnxPBAVxKQcyI! ,xK
TA Here, KcoND is a constant, PBAV is the final detected value obtained by sampling the intake pressure PB detected by the intake pressure sensor 9 according to the routine shown in the flowcharts of FIGS. 5 and 6, which will be described later, and KQCVE is The volumetric efficiency correction coefficient calculated in step 3, KTA
is the intake air temperature correction coefficient set by searching from the map based on the intake air temperature TA detected by the intake air temperature sensor 6 in step 12 of the background job shown in the flowchart of FIG.

In the next step 4, the basic fuel injection amount Tppb obtained in step 3 is subjected to various corrections according to the engine operating state according to the following formula to set the final fuel injection amount Ti.

T i = 2 X T p pbXLAMB
D8XC0EFTsHere, the LAMBDA is
The air-fuel ratio of the engine intake air-fuel mixture detected based on the oxygen concentration in the exhaust gas detected by the oxygen sensor 14 is set as the target air-fuel ratio (
C0EF is an air-fuel ratio feedback correction coefficient that is set to approach the stoichiometric air-fuel ratio), C0EF is various correction coefficients that are mainly set based on the basic correction amount that is set according to the cooling water temperature Tw detected by the water temperature sensor 12, and Ts is This is a voltage correction amount for correcting fluctuations in the invalid injection amount of the fuel injection valve 10 due to battery voltage.

The fuel injection amount Ti set in this way is set in an output register, and when the fuel injection timing synchronized with the engine rotation comes, the latest fuel injection amount Ti set in this output register is read out, and this fuel Fuel is injected and supplied to the engine 1 by outputting an injection pulse signal with a pulse width corresponding to the injection amount Ti to the fuel injection valve 10.

In the routine shown in the flowcharts of FIGS. 5 and 6, the reference angle signal R output from the crank angle sensor 15 is
Intake pressure PB (main output from intake pressure sensor 9) between EF, that is, 180° crankshaft rotation in the case of a 4-cylinder engine
Steady/transient operation of the engine 1 is determined based on the amount of change in the increasing direction and decreasing direction, and the sampling method of the intake pressure PB is switched based on this determination. During steady operation, the intake pressure PB is sampled, and during transient operation, the intake pressure P is
B is sampled and the final detected value PBAV is set.

The routine shown in the flowchart of FIG. 5 is executed at predetermined minute intervals (for example, 1 ms), and the amount of change in the intake pressure PB in the increasing and decreasing directions is detected by this routine.

First, in step 21, a voltage signal output from the crank angle sensor 15 according to the intake pressure PB is A/D converted to obtain an instantaneous value of the intake pressure PB.

Then, in the next step 22, the minimum value P of the intake pressure PB obtained in step 21 and the intake pressure PB up to the previous time is calculated.
Compare with BMIN.

Here, when it is determined that the intake pressure PB obtained in step 21 this time is smaller than the minimum value PBMIN up to the previous time, the process proceeds to step 23 and sets the intake pressure PB obtained in step 21 this time to the minimum value PBMIN. Perform update settings for PBMIN. After setting the update of the minimum value PBMIN, in step 24, the amount of change in the decreasing direction (MAX-+MI
N) is calculated according to the following formula.

[DoAX-+MIN] ←PBMAX-PBMIN The fact that the minimum value PBMIN has been updated this time indicates that the intake pressure PB is changing in the decreasing direction, so
By calculating the minimum value PBMIN updated this time from the maximum value PBMAX set up to the previous time in vA, the amount of change in the decreasing direction [MAX-+)LIN) can be obtained. The maximum value PBMAX and minimum value PBMIN are as follows:
As will be described later, when the reference angle signal REF is output from the crank angle sensor 15, the final detected value PB at that time
Because it is configured so that each AV is set,
The maximum value PBMAX and the minimum value PBMIN are the maximum and minimum values of the intake pressure PB during the reference angle signal REF.

On the other hand, when it is determined in step 22 that the intake pressure PB obtained in step 21 this time is greater than or equal to the minimum value PBMIN, the process proceeds to step 25 and the intake pressure PB obtained in step 21 this time is the maximum value set up to the previous time. Value PBMAX
Determine whether or not it exceeds.

Here, if it is determined that the current value exceeds the maximum value PBMAX, the process proceeds to step 26, sets the intake pressure PB obtained in this step 21 to the maximum value PHMAX, and sets PBMAX.
Configure update settings. After setting the update of PBMAX, the process proceeds to step 27 and the amount of change in the increasing direction (MIN-+M
AX) is calculated according to the following formula.

[MIlt-+MAX] ←PBMAX-PBMIN Also, in step 25, the intake pressure P obtained in step 21 this time
When B is determined to be less than the maximum value PBMAX, the current intake pressure PB is a value located between the maximum value PBMAX and the minimum value PBMIN set up to the previous time, so the maximum and minimum values are The process proceeds to step 28 without performing update settings or calculating the amount of change.

In step 28, the transient flag Ftr is determined to determine whether the engine 1 is in steady or transient operation. The transient flag F
tr is set in the routine shown in the flowchart of FIG. 6, which will be described later, based on the amount of change in the increasing direction and the amount of change in the decreasing direction calculated as described above, and when set to 1, the engine 1 indicates a state in which transient operation is determined, and when zero is set, it indicates a state in which steady operation is determined.

Therefore, when it is determined in step 28 that the transient flag Ftr is 1, the engine 1 is in a transient operating state;
In this case, proceed to step 29 and proceed to step 21 this time.
Set the intake pressure PB obtained in step 1 to the final detected value PBAV. Therefore, when the engine 1 is in a transient operating state, the final detected value PBAV is updated every minute according to the intake pressure detected value PB according to this routine. During transient operation of engine 1, the true intake pressure PB corresponding to fuel supply amount control increases and decreases, and it is necessary to shorten the update interval time of the final detected value PBAV as much as possible to ensure detection responsiveness. Sometimes, the final detected value PBAV is updated every time this routine is executed.

On the other hand, when it is determined in step 28 that the transient flag Ftr is zero and the engine 1 is in a steady operating state, the intake pressure PB detected by the intake pressure sensor 9 also pulsates due to the pressure pulsations occurring in the intake passage. Therefore, in the same way as during transient operation, the intake pressure PB is
When the final detected value PBAV is updated by sampling the pulsation, the final detected value PBAV picks up the pulsation and fluctuates. In order to ensure the inertia effect of the intake and exhaust of the engine 1, for example, in a four-cylinder engine, the intake system is generally set so that pressure pulsations occur with one cycle of crank angle 180 degrees.

The pulsation of the intake pressure PB in the steady operating state of the engine 1 is
It does not correspond to changes in the required fuel amount (intake air amount), but since it is a steady operating state, the true intake pressure PB corresponding to the required fuel amount is constant. Therefore, when the final detected value PBAV pulsates by sampling the intake pressure PB at minute intervals as in the case of transient operation, this final detected value P
The fuel injection amount Ti set using BAV will fluctuate, leading to fluctuations in the air-fuel ratio. Therefore, in this routine, the final detected value PBAV is not updated and this routine is ended, and the final detected value PBA is updated in the routine shown in the flowchart of FIG. 6 to avoid the influence of pulsation.
Make sure that V is updated.

In the flowchart of FIG. 5, step 30 whose flow direction is indicated by a dotted line is necessary when sampling the intake pressure during steady operation according to the routine shown in the flowchart of FIG. 7, which will be described later. This step is unnecessary when sampling the intake pressure PB using the routines shown in the flowcharts of FIGS. 5 and 6 as one set.

The routine shown in the flowchart of FIG. 6 is executed every time the reference angle signal REF is output from the crank angle sensor 15.

Here, first in step 41, the recent reference angle signal R
The difference ΔPB between the two is calculated by subtracting the amount of change in the increasing direction (MIN-+MAX) from the amount of change in the decreasing direction (MAX→MIN) calculated and set for each EF according to the flowchart in FIG.

Then, in the next step 42, a weighted average value ΔPBAV of the deviation ΔPB is calculated according to the following equation.

In addition, ΔPBA used for calculating the weighted average value ΔPBAV above
V is the value calculated in step 42 when this routine was executed last time, and the deviation PB is the value calculated in step 41 this time, and in step 42, the weighted average value ΔPBAV up to the previous time and the current deviation ΔPB are calculated. is weighted average.

In the next step 43, the deviation ΔΔPB between the deviation ΔPB calculated in step 41 and the weighted average value PBAV calculated in step 42 is calculated.

Since the weighted average value ΔPBAV is a value that blunts the change in the deviation ΔPB, the deviation ΔΔPB is equal to the deviation ΔP.
This is a value that indicates whether or not B is changing significantly, and if the change in ΔPB is small during steady operation, ΔΔPB should be a value close to zero.

In other words, ΔPB is not necessarily zero even during steady operation, but if the engine 1 is in steady operation and the intake pressure PB is pulsating around a constant value, ΔPB will be approximately constant, so ΔΔPB has a value close to zero. However, if the engine 1 is operated in a transient manner and the intake pressure PB shows an overall increasing or decreasing tendency even though it is accompanied by pulsations, the balance between the amount of change in the increasing direction and the amount of change in the decreasing direction during steady operation is When the deviation ΔPB collapses and the intake pressure PB suddenly changes during sudden acceleration or deceleration, the deviation ΔPB changes greatly, resulting in ΔΔ
The absolute value of PB increases during sudden acceleration and deceleration.

When the deviation ΔΔPB corresponding to the rate of change in the true intake pressure PB is calculated as described above, the next step 44
Then, the deviation ΔΔPB is expressed as the degree of transient operation of the engine 1 (“
It is converted into a membership value mtr indicating the degree of conformity to the "transient operation" set. control unit 1 in advance
A membership function (conversion map) for converting the deviation ΔΔPB into a membership value mtr is stored in the ROM of the microcomputer built in 1, and the deviation ΔΔ calculated in step 43 from this map is stored in the ROM of the microcomputer 1.
The membership value mtr corresponding to PB is searched.

The membership value mtr is a state that is completely suitable for determining that the engine 1 is in a transient operating state when its absolute value (plus/minus of the numerical value depends on the difference in acceleration/deceleration) is 1, The closer it gets to zero, the closer it gets to the state that should be determined to be a steady operating state, and when it is zero, it indicates a state that is completely suitable for determining that the engine is in a steady operating state. 1
The purpose is to quantify the states of steady-state operation and transient operation, which are difficult to express numerically, as the degree of compliance for each. Note that the deviation ΔΔPB is the membership value mtr
The membership function used for the conversion is set through experiments or the like while making the actual intake pressure PB (true intake pressure PB) change correspond to the deviation ΔΔPB.

The deviation ΔPB between the amount of change in the decreasing direction (MAX-+MIN) and the amount of change in the increasing direction CMIN-+MAX), and the deviation ΔPB
After converting the weighted average value ΔPBAV of By comparing the value with a predetermined value (for example, 0.3),
It is determined whether the engine 1 is in a steady operating state or a transient operating state. Note that the predetermined value is appropriately set depending on the engine 1 based on the membership function, the relationship with the pressure pulsation generation situation of the engine 1, and the like.

If the absolute value of the membership value mtr is 1, it indicates that it is completely compatible with the transient operation determination, so in step 45, the absolute value of the membership value mtr is greater than or equal to the predetermined value and is closer to 1. If it is determined that this is the case, the process proceeds to step 46 to perform transient operation determination. Step 4
In step 6, the transient flag Ftr is set to 1, which corresponds to transient determination.

On the other hand, when it is determined in step 45 that the absolute value of the membership value mtr is less than the predetermined value, the process proceeds to step 47 to determine steady operation since the absolute value of the membership value mtr is closer to zero than the predetermined value.

In step 47, the transient flag Ftr is set to zero corresponding to the determination of steady operation, and in the next step 48, the latest intake pressure PB is set to the final detected value PBAV.

In this way, the transient flag Ftr is set by comparing the absolute value of the membership value mtr with a predetermined value, and the determination of the transient flag Ftr determines whether the steady state in step 28 of the flowchart of FIG.・Transient operation determination is performed.

When the transient flag Ftr was determined to be zero in the flowchart of FIG. 5, the final detection value PBAV was not updated, but instead, the final detection value PBAV was updated in step 47 of the flowchart of FIG. It will be done. Therefore, according to the sampling method of the intake pressure PB according to the flowcharts in FIGS. 5 and 6, sampling is performed at minute intervals when determining the transient operation of the engine 1, and when the engine 1 is in steady operation, the reference angle Sampling is performed for each signal REF (constant crank angle).

During steady operation of the engine 1, although the true intake pressure PB is constant, the detected value of the intake pressure PB is pulsating due to the influence of pressure pulsations occurring in the intake passage.
By sampling the intake pressure at a period that substantially matches the period of the pulsation, it is possible to avoid the pulsation from being picked up by the final detected value PBAV. However, the reference angle signal REF is set so that the center value of the pulsation is sampled.
It is obvious that it is desirable to set the pulsation to be output at the timing when the pulsation crosses its center value.

After setting the transient flag Ftr and setting the final detected value PBAV during steady operation, in the next step 49, the intake pressure PB(
7) In order to wait for setting the maximum (iPBMAX) and minimum value PBMIN and detecting the amount of change in the decreasing direction (MAX-+MIN) and the amount of change in the increasing direction (MIN-MAX), set the latest final value to the maximum value PBMAX and minimum value PBMIN. Detection value P
While setting BAV, the amount of change in the decreasing direction [:MAX-
MIN] and the amount of change in the increasing direction CMIN→MAX) are reset to zero.

As described above, in this embodiment, in the configuration in which the sampling method of the intake pressure PB is switched between steady and transient operation of the engine 1, the amount of change in the decreasing direction [MAX-+MIN] of the intake pressure PB between the reference angle signal REF and the increasing direction Amount of change (
MxN-+nnx) are detected, the state of change of the deviation ΔPB between the two is known, and when PB is changing to the deviation, it is determined that the engine 1 is in a transient operating state. This makes it possible to accurately determine steady-state operating conditions that require intake pressure sampling to attenuate and avoid pulsation effects, while transient operating conditions that require detection responsiveness in sampling due to changes in the true intake pressure PB. can be determined with high accuracy, and intake pressure PB sampling can be performed using a sampling method suitable for each in steady and transient operation.

In addition, when controlling the sampling method of the intake pressure PB depending on the steady/transient operation of the engine 1,
The sampling method for each transient operation is as described in Section 5 above.
Other embodiments of the sampling method, which are not limited to those shown in the figure and the flowchart of FIG. 6, will be described below.

The routine shown in the flowchart of FIG. 7 is a pair of the routine shown in the flowchart of FIG. As in the first embodiment, this is performed at minute intervals.

The routine shown in the flowchart of FIG. 7 is executed every time the reference angle signal REF is output from the crank angle sensor 15, similar to the flowchart of FIG.
Here, each arithmetic processing in steps 51 to 54 is the same as steps 41 to 44 in the flowchart of FIG. 6, so a description thereof will be omitted, and steps from step 55 onward will be described, although certain explanations will be repeated.

PB to the deviation between the amount of change in the decreasing direction (MAX-+MIN) and the amount of change in the increasing direction CMIN-+MAX), and the deviation ΔPB
Calculate the weighted average value ΔPBAV and the deviation ΔΔPB,
When this deviation ΔΔPB is converted into a membership value mtr, in the next step 55, the membership value mt
The absolute value of r is compared with a predetermined value (for example, 0.4).

When it is determined that the absolute value of the membership value mtr is greater than or equal to a predetermined value, the engine 1 is in a transient operating state, so the process proceeds to step 56, where the transient flag Ftr is set to 1, and the membership value mtr is set to 1. When it is determined that the absolute value of mtr is less than a predetermined value, the engine 1 is in a steady operating state, so the process proceeds to step 57 and zero is set in the transient flag Ftr.

When engine 1 is determined to be in steady operation, the transient flag F is set in step 57.
After setting tr to zero, the arithmetic mean value (the sum of sample values divided by the number of sample values) of the intake pressure PB is calculated in step 58, and the arithmetic mean value is set as the final detected value PBA.
Enter into V.

In order to perform the arithmetic mean of the intake pressure PB as described above, in step 30 (the step in which the flow direction is indicated by a dotted line) in the flowchart of FIG. An operation of adding to PBSUM and counting up a counter value n for counting the number of samples are performed, and in step 58, the integrated value PBSUM obtained between the outputs of the reference angle signal REF is added to the counter. By dividing by the value n, the calculated average of the intake pressure PB between the outputs of the reference angle signal REF can be obtained.

Therefore, in the case of the second embodiment shown in the flowchart of FIG. 7, during transient operation, the intake pressure PB is sampled at minute intervals as in the first embodiment, but during steady operation, the intake pressure PB is sampled at minute intervals between the reference angle signals REF. The arithmetic mean value of the intake pressure PB sampled at each time is determined and the reference angle signal RE is calculated.
The arithmetic mean value is set to the final detected value PBAV for each F.

During steady operation, if the configuration is such that the arithmetic mean value of the intake pressure PB between the reference angle signals REF is set to the final detected value PBAV, the output timing of the reference angle signal REF will be around the point where the pulsation of the intake pressure PB crosses its center value. Even if it is not set to , the pulsation shows one period of change during the 18° rotation, which is the output interval of the reference angle signal REF (in the case of a 4-cylinder engine), so the arithmetic average result almost matches the center value of the pulsation. Therefore, even when pressure pulsation occurs during steady operation, the true intake pressure PB (pulsation center value) can be set as the final detected value PBAV.

In step 59, the maximum value PBMAX and the minimum value PBMI of the intake pressure PB during the next reference angle signal REF are determined.
In order to wait for the setting of N and the detection of the amount of change in the decreasing direction (MAX → MIN) and the amount of change in the increasing direction (MIN → MAX), the latest final detected value PBAV is set for the maximum value PBMAX and the minimum value PBMIN, while Amount of change in decreasing direction (M
AX-+MIN) and increasing direction change CMIN-+MA
X) is reset to zero.

Also, in step 60, the next reference angle signal R
In order to obtain the arithmetic mean of the intake pressure PB during EF, the integration value PBSUM and the count value n are each reset to zero, and the integration calculation and calculation in step 30 of the flowchart of FIG. 5 described above are carried out until the next reference angle signal REF. make it happen.

Furthermore, other embodiments of the sampling method in which the intake pressure PB is sampled in different ways during steady and transient operation of the engine 1 will be described according to the routines shown in the flowcharts of FIGS. 8 and 9, respectively.

The routine shown in the flowchart of FIG. 8 is executed every predetermined minute time (for example, 1 ms), and each calculation process in steps 71 to 77 is as follows:
Steps 21-- in the flowchart of FIG. 5 described above
This is similar to step 27, and in steps 71 to 77, the amount of change in the direction of decrease [MAX-+MIN] and the amount of change in the direction of increase (MIN-+MAX) of the intake pressure PB between the reference angle signal REF are detected, respectively. It has become.

Then, in the next step 78, the transient flag Ftr is determined. This transient flag Ftr is set according to the routine shown in the flowchart of FIG. 9, which will be described later, in the same manner as the flowcharts of FIGS. 6 and 7 described above, and 1 is set in the transient flag Ftr. Sometimes, it is determined that the engine 1 is in a transient operation, and when the transient flag Ftr is set to zero, it is determined that the engine 1 is in steady operation.

When it is determined in step 78 that the transient flag Ftr is 1, the process proceeds to step 79 and the final detected value PBAV
This time, the intake pressure PB obtained by A/D conversion in step 71 is
Set. Also, in step 78, the transient flag Ftr
When it is determined that is zero, the process proceeds to step 80, where the intake pressure PB is weighted averaged according to the following equation, and the result is set as the final detected value PBAV.

In the above weighted average calculation formula, the numerator PBA■ is the current final detected value, and by weighted averaging this final detected value PBAV and the latest intake pressure PB, the intake pressure P
The final detection (!P B A V is newly set by slowing down the change in B, and 2X is the past final detection value PB
This indicates weighting for AV, and the larger 2× is, the more the change in the final detected value PBAV can be blunted.

That is, when the transient operation of the engine 1 has not been determined, the final detected value PBAV of the intake pressure PB is updated and set every time the routine shown in the flowchart of FIG. 8 is executed at minute intervals to ensure detection responsiveness. However, when the steady operation of the engine 1 is determined, the change in the final detected value PB is slowed down with respect to the change in the intake pressure PB by calculating the weighted average according to the above-mentioned calculation formula, so that the change in the final detected value PB becomes slower with respect to the change in the intake pressure PB. This is to prevent pressure pulsations occurring from being picked up by the final detected value PBAV.

On the other hand, the routine shown in the flowchart of FIG. 9 is executed every time the reference angle signal REF is output from the crank angle sensor 15, and each calculation process in steps 91 to 94 is performed as described above. Although similar to steps 41 to 44 or steps 51 to 54 in the flowcharts of FIGS. 6 and 7, and detailed explanation will be omitted, in steps 91 to 94,
PB is calculated for the deviation between the amount of change in the decreasing direction (MAX→MIN) and the amount of change in the increasing direction (?llN-+MAX), and a weighted average value ΔPBAV of PB is calculated for the deviation, and further, the above-mentioned ΔP B / Deviation Δ between '1゜■ and 8PB
ΔPB is calculated, and the deviation ΔΔPB is converted into membership 4Fimt,r indicating the degree of transient operation using a predetermined membership function.

Then, in step 95, the transient/steady state of the engine 1 is determined by comparing the absolute value of the membership value mtr obtained by converting the deviation ΔΔPB with a predetermined value (for example, 0.25).

When the absolute value of the membership value mtr is greater than or equal to a predetermined value, the amount of change in the decreasing direction of the intake pressure PB (MAX-
Since the engine 1 is in a transient operating state where the deviation ΔPB between +[N) and the amount of change in the increasing direction (MIN-MAX) is changing significantly, the process advances to step 96 and the transient flag Ftr is set to 1. Furthermore, when the absolute value of the membership value mtr is smaller than a predetermined value, the deviation ΔPB between the amount of change in the decreasing direction [MAX-+MIN] and the amount of change in the increasing direction [MIN-+MAX] of the intake pressure PB is stable. Since the engine 1 is in a steady operating state, the process advances to step 97 and the transient flag Ftr is set to zero. The transient flag Ftr set in this way is determined in step 78 of the routine shown in the flowchart of FIG. 8, and the steady state/transient state of the engine 1 is determined.

Once the transient flag Ftr is set, the next step 98 is to wait for the detection of the amount of change in the decreasing direction (MAX→MIN) and the amount of change in the increasing direction [HIN-+MAX) of the intake pressure PB between the next reference angle signal REF. In order to
-+MIN) and the amount of change in the increasing direction (MIN→old χ) are each reset to zero.

In this embodiment, the intake pressure detected by the intake pressure detection device according to the present invention is used for fuel injection control, but in addition to fuel injection control, it can also be used for other controls such as ignition timing control. Furthermore, by using the basic fuel injection amount 'rppb set in this embodiment for ignition timing control and automatic shift control, it is possible to improve the accuracy of ignition timing control, etc.

In addition, the intake pressure P
In the configuration for switching the sampling method of B, this embodiment shows a plurality of sampling methods for the intake pressure PB, but the sampling method is not limited to the one shown in this embodiment, and may be any one of the sampling methods required in steady and transient operation of the engine 1. Any suitable sampling performance is acceptable as long as it provides the desired sampling performance.

Further, a constant may be variably set for weighting when calculating the weighted average of the intake pressure PB in accordance with the membership value mtr indicating the degree of transient operation of the engine 1 set in the above embodiment.

<Effects of the Invention> As described above, according to the present invention, the engine is configured to determine whether the engine is steady or transient based on the deviation between the amount of change in the increasing direction and the amount of change in the decreasing direction of the intake pressure between constant crank angles, Since the intake pressure sampling means is switched and selected based on this steady/transient discrimination, it is possible to sample the intake pressure based on highly accurate steady/transient discrimination, and the fuel consumption due to intake pressure sampling errors is The occurrence of engine control errors such as supply amount control can be avoided.

In particular, if the configuration is such that steady/transient discrimination is performed based on the deviation between the amount of change in the increasing direction and the amount of change in the decreasing direction, and the average value of the deviation, the phase of the pressure pulsation that occurs during steady operation can be determined. The stationary/transient state of the engine can be discriminated with high precision regardless of the current state, and sampling switching based on the steady/transient discrimination can be performed satisfactorily.

Furthermore, the deviation between the amount of change in the increasing direction and the amount of change in the decreasing direction and the average value of the deviations are converted into a value indicating the degree of steady or transient operation, and the engine is adjusted based on this converted value. By distinguishing between steady state and transient state, it becomes possible to quantitatively grasp the steady and transient operating state of the engine, and it becomes possible to easily and accurately distinguish between steady state and transient state, which also makes it possible to switch sampling with high precision. become.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a block diagram showing the configuration of the present invention, Fig. 2 is a system schematic diagram showing one embodiment of the present invention, and Figs. Flowchart showing control details,
FIG. 7 is a flowchart showing the control contents of the second embodiment;
8 to 9 are flowcharts 1 and 10 respectively showing the control contents of the third embodiment, and FIG. 10 is a time chart for explaining problems in the conventional steady/transient discrimination. 1... Engine 9... Intake pressure sensor 11...
Control unit 15...Crank angle sensor Patent applicant: Japan Electronics Co., Ltd. Representative Patent attorney: Fujio Sasashima

Claims (3)

[Claims] (1) An intake pressure detection means provided in the intake passage of the engine to detect intake pressure; a crank angle position detection means that outputs a detection signal at each constant crank angle position of the engine; and detection from the crank angle position detection means. Increase/decrease change amount detection means for respectively detecting the amount of change in the increasing direction and the amount of change in the decreasing direction of the detected intake pressure while the signal is output; A steady/transient operation discrimination means for discriminating between steady and transient operation of the engine based on the deviation from the amount of change in direction; and a mutual system for sampling the intake pressure detected by the intake pressure detection means and setting it as a final detected value. An internal combustion engine characterized by comprising: sampling switching means for sampling intake pressure by switching and selecting different sampling means for transient operation and sampling means for steady operation according to the determination of steady/transient operation. Engine intake pressure detection device. (2) A deviation change that calculates the deviation between the amount of change in the increasing direction and the amount of change in the decreasing direction detected by the increase/decrease change amount detecting means, instead of the steady/transient operation determining means, and the average value of the deviations. 2. The engine according to claim 1, further comprising: a calculating means; and a deviation change dependent steady/transient operation determining means for determining steady/transient operation of the engine based on the deviation calculated by the deviation change calculating means. Intake pressure detection device for internal combustion engines. (3) The deviation calculated by the deviation change calculation means is converted into a value indicating the degree of steady operation or transient operation, and based on the converted value, the steady/transient operation is determined by the deviation change dependent steady/transient operation determination means. 3. The intake pressure detection device for an internal combustion engine according to claim 2, further comprising steady/transient operation degree converting means for converting the degree of operation.