JP3873608B2 - Internal combustion engine control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an internal combustion engine control apparatus that can accurately drive an internal combustion engine in accordance with an operation request of a driver such as a vehicle.
[0002]
[Prior art]
Conventionally, as a control device for an internal combustion engine, a map is used when setting a target throttle opening in order to obtain a target intake air amount to be taken into the internal combustion engine, as described in JP-A-10-30469. The one that performs setting is known.
[0003]
This control device for an internal combustion engine intends to optimize when converting target values such as a target filling amount and a target intake air amount with respect to a load variable into target values for setting a throttle valve of the internal combustion engine.
[0004]
[Problems to be solved by the invention]
However, in such a control device for an internal combustion engine, control is performed in a steady state where there is no drive fluctuation in the internal combustion engine. In a transient state when the drive fluctuates, an accurate target corresponding to the fluctuation is obtained. It is difficult to set the throttle angle and it is difficult to cope with a transient state.
[0005]
In addition, when setting the target throttle opening for obtaining the target intake air amount, a large number of calculations are required based on the map, and enormous adaptation processing is required to obtain more appropriate map data.
[0006]
Therefore, the present invention has been made to solve such a technical problem, and can accurately set a target throttle angle in a transient state of drive fluctuations of an internal combustion engine, and reduce calculation data and calculation processing contents. An object of the present invention is to provide an internal combustion engine control device that can achieve the above.
[0007]
[Means for Solving the Problems]
That is, the internal combustion engine control apparatus according to the present invention is based on the target intake pipe pressure calculated from the target intake air amount to be taken into the internal combustion engine, and the opening area before the throttle valve is operated and the opening area after the throttle valve is operated. Based on the opening area ratio calculation means for calculating the opening area ratio between the throttle valve and the throttle opening before the operation of the throttle valve, the opening area ratio before and after the operation of the throttle valve and the correspondence data of the throttle opening and the opening area of the throttle valve are obtained. And a target throttle opening calculating means for calculating a target throttle opening after the operation of the throttle opening.
[0008]
Moreover, the internal combustion engine control apparatus according to the present invention is characterized in that the opening area ratio calculating means calculates the opening area ratio using the following expression based on the target intake pipe pressure.
[0009]
At (t ₀₊ ) / At (t ₀₋ ) = ((Pm (t ₀ + Δt) −Pm (t ₀ )) / (Δt · (R / V) · T) + mc (t ₀ ) −mp (t ₀ )) / mt (t _0- )
In this equation, At (t ₀₊ ) / At (t ₀₋ ) is the ratio of the opening area before and after the operation of the throttle valve, At (t ₀₊ ) is the opening area after the operation of the throttle valve, and At (t _{0). -} ) Is the opening area before operation of the throttle valve, Pm (t ₀ + Δt) is the target intake pipe pressure after a certain time Δt has elapsed from time t ₀ , Pm (t ₀ ) is the intake pipe pressure at time t ₀ , R is Gas constant, V is the cylinder volume of the internal combustion engine, T is the temperature, mc (t ₀ ) is the amount of intake air to the cylinder, mp (t ₀ ) is the amount of air flowing in from a path other than the throttle valve, and mt (t _{0) -} ) Is the amount of air passing through the throttle before the throttle valve is operated.
[0010]
According to these inventions, since the opening area ratio before and after the operation of the throttle valve according to the target intake pipe pressure is calculated, and the target throttle opening is calculated using the opening area ratio or the like, the drive fluctuations of the internal combustion engine are reduced. Even in the generated transient state, it is possible to accurately set the target throttle opening corresponding to the fluctuation. In addition, since complicated map processing is not required when setting the target throttle opening, it is possible to reduce calculation data and calculation processing contents.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.
[0012]
FIG. 1 is an explanatory diagram of an internal combustion engine control apparatus according to this embodiment.
[0013]
As shown in the figure, the internal combustion engine control device is a device that controls driving of an engine 2 that is an internal combustion engine mounted on a vehicle. The engine 2 includes, for example, a variable valve mechanism, and includes a variable valve timing mechanism 5 that changes opening and closing timings of the intake valve 3 and the exhaust valve 4 as the variable valve mechanism. The variable valve timing mechanism 5 is electrically connected to the ECU 6, operates based on a control signal output from the ECU 6, and outputs a detection signal related to valve timing to the ECU 6 via a detection sensor 7 such as a cam position sensor. To do.
[0014]
The engine 2 is provided with a crank position sensor 12. The crank position sensor 12 is a sensor that detects the engine speed, is connected to the ECU 6, and outputs a detection signal to the ECU 6.
[0015]
The engine 2 is provided with an injector 9 that injects fuel into the combustion chamber 8. The injector 9 is fuel injection means for supplying fuel to the combustion chamber 8, and is installed for each cylinder 10 provided in the engine 2. The combustion chamber 8 is formed above the piston 11 disposed in the cylinder 10. An intake valve 3 and an exhaust valve 4 are disposed above the combustion chamber 8.
[0016]
An intake pipe 20 including an intake manifold, a surge tank, and the like is connected to the upstream side of the intake valve 3. A throttle valve 23 is provided in the middle of the intake pipe 20. The throttle valve 23 operates based on a control signal from the ECU 6. The throttle opening of the throttle valve 23 is detected by a throttle position sensor 24 and input to the ECU 6.
[0017]
An air cleaner 22 is installed in the upstream portion of the throttle valve 23 of the intake pipe 20. An air flow meter 25 is provided at a downstream position of the air cleaner 22. The air flow meter 25 is intake air amount detection means for detecting the intake air amount. A detection signal of the air flow meter 25 is input to the ECU 6.
[0018]
The ECU 6 controls the entire internal combustion engine control device 10 and is mainly composed of a computer including a CPU, a ROM, and a RAM. Various control routines including an engine control routine are stored in the ROM.
[0019]
A purge passage 30 joins the downstream portion of the throttle valve 23 of the intake pipe 20. The purge passage 30 is a passage through which predetermined air flows into the engine 2 without passing through the throttle valve 23, and is connected to a charcoal canister (not shown), and introduces fuel evaporative gas from the charcoal canister into the intake system of the engine 2. To do. For this reason, the amount of air sucked into the engine 2 is the sum of the amount of air passing through the slot valve 23 and the amount of air introduced into the intake pipe 20 through the purge passage 30.
[0020]
Next, the operation of the internal combustion engine control apparatus according to this embodiment will be described.
[0021]
FIG. 2 is a flowchart showing the operation of the internal combustion engine control device.
[0022]
In step S10 (hereinafter, simply referred to as “S10”. The same applies to other steps), the throttle opening degree TA, the engine speed NE, the valve timing VT, and the air flow rate QA are read. .
[0023]
Reading of the throttle opening degree TA is performed based on the output signal of the throttle position sensor 24. Reading of the engine speed NE is performed based on an output signal of the crank position sensor 12. Reading of the valve timing VT is performed based on the output signal of the detection sensor 7. Reading of the air flow rate QA is performed based on an output signal of the air flow meter 25.
[0024]
Then, the process proceeds to S12, and the target intake air amount mc (t ₀ + Δt) is calculated. The target intake air amount mc (t ₀ + Δt) is set based on the accelerator operation state of the driver of the vehicle, and is calculated based on, for example, the accelerator opening (accelerator operation amount). Further, the target intake air amount mc (t ₀ + Δt) is an intake air amount after a fixed time Δt has elapsed from the current time t ₀ . The fixed time Δt is a time set based on, for example, the time until the intake valve 3 is closed, and is set in the ECU 6 in advance.
[0025]
Then, the process proceeds to S14, and the target intake pressure Pm (t ₀ + Δt) is calculated. The target intake pressure Pm (t ₀ + Δt) is calculated based on the target intake air amount mc (t ₀ + Δt). For example, the relationship between the intake air amount mc and the intake pressure Pm is approximated by a linear expression of mc = a · Pm−b, and the target intake pressure Pm (t ₀ + Δt) is obtained by back calculation using this linear expression.
[0026]
If the amount of air flowing into the intake pipe 20 is min (t ₀ ) and the amount of air flowing out from the intake pipe 20, that is, the amount of intake air into the cylinder is mc (t ₀ ), the amount of air flowing in the intake pipe 20 is min. (t _0), the outflow air quantity mc (t ₀₎ and the mass conservation law is expressed by the following equation (1).
[0027]
Pm (t ₀ + Δt) = Pm (t ₀ ) + Δt · (R / V) · T · (min (t ₀ ) −mc (t ₀ )) (1)
Here, Pm (t ₀ ) is the current intake pressure. R is a gas constant, V is a cylinder volume when the intake valve 3 is closed, and T is a temperature.
[0028]
Therefore, from the above equation (1), the inflow air amount min (t ₀ ) is expressed by the following equation (2).
[0029]
min (t ₀ ) = (Pm (t ₀ + Δt) −Pm (t ₀ )) / (Δt · (R / V) · T) + mc (t ₀ ) (2)
By setting the throttle opening so that the inflow air amount min (t ₀ ) of the equation (2) can be realized, engine control according to the driver's accelerator operation becomes possible.
[0030]
By the way, the air flowing into the intake pipe 20 is not only passing through the throttle valve 23 but also flowing through a path other than the throttle valve 23 such as the purge passage 30. Here, if the amount of air passing through the throttle valve 23 passing through the throttle valve 23 and flowing into the intake pipe 20 is mt, and the amount of air flowing in from a path other than the throttle valve 23 is mp, the amount of air flowing into the intake pipe 20 is min. It is represented by the following formula (3).
[0031]
min = mt + mp (3)
Then, the process proceeds to S16, and the throttle passing air amount mt (t ₀ ) at time t ₀ is calculated. The throttle passage air amount mt (t ₀ ) is calculated by the following equation (4).
[0032]
mt (t ₀ ) = (Pm (t ₀ + Δt) −Pm (t ₀ )) / (Δt · (R / V) · T) + mc (t ₀ ) −mp (t ₀ ) (4)
This formula (4) is derived from the above formulas (2) and (3). When the inflow air amount mp (t ₀ ) from the path other than the throttle valve 23 is the air amount flowing in through the purge passage 30, the inflow air amount mp (t ₀ ) is, for example, an air-fuel ratio sensor (not shown) or O 2 A value calculated based on an output signal from a sensor or the like or a value directly detected by a flow rate detection sensor or the like is used.
[0033]
Then, the process proceeds to S18, and the throttle opening area ratio At (t ₀₊ ) / At (t ₀₋ ) is calculated before and after the operation of the throttle valve 23. At (t ₀₊ ) is the throttle opening area after the operation of the throttle valve 23, and At (t ₀₋ ) is the throttle opening area before the operation of the throttle valve 23. The calculation of the throttle opening area ratio At (t ₀₊ ) / At (t ₀₋ ) is performed using the following equation (5).
[0034]
At (t ₀₊ ) / At (t ₀₋ ) = ((Pm (t ₀ + Δt) −Pm (t ₀ )) / (Δt · (R / V) · T) + mc (t ₀ ) −mp (t ₀ )) / mt (t _0- ) (5)
Note that mt (t ₀₋ ) is the amount of air passing through the throttle before the operation of the throttle valve 23. As mt (t ₀₋ ), the value of mt before the throttle valve operation is used. Further, At (t ₀₋ ) is the value of At before the throttle valve operation.
[0035]
Here, when the throttle valve 23 operates stepwise at time t ₀ , the throttle passing air amounts mt (t ₀₋ ) and mt (t ₀₊ ) before and after the throttle valve operation are calculated using the throttle opening area At. (6).
[0036]
mt (t ₀₊ ) = (At (t ₀₊ ) / At (t ₀₋ )) · mt (t ₀₋ ) (6)
In this equation (6), since the response of the intake pressure Pm is sufficiently slow with respect to the change of the throttle valve 23, it is assumed that the ratio of the amount of air passing through the throttle before and after the throttle valve operation is equal to the approximate opening area ratio. It will be guided.
[0037]
By substituting the throttle air flow mt of the formula (6) (t ₀₊₎ to throttle air flow mt (t ₀₎ of formula (4), Equation (5) is derived.
[0038]
Then, the process proceeds to S20, and the target throttle opening degree TA (t ₀₊ ) is calculated. The target throttle opening degree TA (t ₀₊ ) is calculated using correspondence data in which the throttle opening degree (throttle angle) and the throttle opening area are associated with each other.
[0039]
For example, as shown in FIG. 3, a table in which the throttle opening (throttle angle) and the throttle opening area are associated with each other is stored in the ECU 6 in advance, and the throttle opening TA before the operation of the throttle valve 23 is stored using the table. (t _0-) corresponding to the determined throttle opening area At (t _0-). Next, the obtained At (t ₀₋ ) is substituted into the equation (5), and the throttle opening area after throttle operation, the throttle opening area At (t ₀₊ ) is calculated. Then, the throttle opening degree TA (t ₀₊ ) corresponding to At (t ₀₊ ) is obtained using the table of FIG.
[0040]
Then, by operating the throttle valve 23 in accordance with the target throttle opening degree TA (t ₀₊ ) obtained in S20, engine control according to the driver's accelerator operation becomes possible.
[0041]
As described above, according to the internal combustion engine control apparatus according to the present embodiment, the change rate of the opening area of the throttle valve, that is, the throttle opening area ratio, required to obtain the target intake pipe pressure calculated from the target intake air amount. Calculate and calculate the throttle opening area necessary to obtain the target intake pipe pressure from the current throttle opening area calculated from the current throttle opening (throttle angle) and the calculated throttle opening area ratio before the throttle valve operation, The throttle opening (throttle angle) corresponding to this throttle opening area is calculated as the target throttle opening (target throttle angle). That is, the opening area ratio before and after the operation of the throttle valve 23 according to the target intake pipe pressure Pm is calculated, and the target throttle opening is calculated using the opening area ratio and the like. For this reason, even in the transient state in which the drive fluctuation of the internal combustion engine occurs, the target throttle opening corresponding to the fluctuation can be set accurately.
[0042]
Further, since the target throttle opening can be set using an arithmetic expression such as Expression (5) and complicated map processing is not required, the calculation data and the contents of the arithmetic processing can be reduced.
[0043]
Furthermore, since the target throttle opening can be calculated by substituting a predetermined value into an arithmetic expression such as Expression (5) according to the driver's accelerator operation, the control algorithm is simple and the arithmetic processing can be performed quickly. Accordingly, quick control is possible, and appropriate control can be performed in a transient state when the internal combustion engine is driven.
[0044]
In the internal combustion engine control apparatus according to the present embodiment, as shown in S14 to S18 of FIG. 2, each process of the calculation of the target intake pressure, the calculation of the amount of air passing through the throttle, and the calculation of the throttle opening area ratio is performed individually. Although described as a process, these calculation processes may be performed as one calculation process.
[0045]
【The invention's effect】
As described above, according to the present invention, an accurate target throttle opening according to the fluctuation can be set even in the transient state in which the driving fluctuation of the internal combustion engine occurs.
[0046]
In addition, since complicated map processing is not required when setting the target throttle opening, it is possible to reduce calculation data and calculation processing contents.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of an internal combustion engine control apparatus according to an embodiment of the present invention.
FIG. 2 is a flowchart showing an operation of the internal combustion engine control device of FIG. 1;
3 is an explanatory diagram of a throttle angle-throttle opening area characteristic in a control target of the internal combustion engine control device of FIG. 1; FIG.
[Explanation of symbols]
2 ... Engine, 3 ... Intake valve, 4 ... Exhaust valve, 5 ... Variable valve timing mechanism, 6 ... ECU, 20 ... Intake pipe, 23 ... Throttle valve, 24 ... Throttle position sensor, 25 ... Air flow meter, 30 ... Purge passage .

Claims (2)

An opening area ratio for calculating an opening area ratio between an opening area before the throttle valve operation and an opening area after the throttle valve operation based on a target intake pipe pressure calculated from a target intake air amount to be taken into the internal combustion engine A calculation means;
Based on the throttle opening before the operation of the throttle valve, the operation of the throttle opening is performed using the opening area ratio before and after the operation of the throttle valve and the correspondence data of the throttle opening and the opening area of the throttle valve. A target throttle opening calculating means for calculating a later target throttle opening;
An internal combustion engine control device comprising: 2. The internal combustion engine control device according to claim 1, wherein the opening area ratio calculating means calculates the opening area ratio using the following expression based on the target intake pipe pressure.
At (t ₀₊ ) / At (t ₀₋ ) = ((Pm (t ₀ + Δt) −Pm (t ₀ )) / (Δt · (R / V) · T) + mc (t ₀ ) −mp (t ₀ )) / mt (t _0- )
In this equation, At (t ₀₊ ) / At (t ₀₋ ) is the ratio of the opening area before and after the operation of the throttle valve, At (t ₀₊ ) is the opening area after the operation of the throttle valve, and At (t _{0 -} ) Is the opening area before the operation of the throttle valve, Pm (t ₀ + Δt) is the target intake pipe pressure after a fixed time Δt has elapsed from time t ₀ , Pm (t ₀ ) is the intake pipe pressure at time t ₀ , R is Gas constant, V is the cylinder volume of the internal combustion engine, T is the temperature, mc (t ₀ ) is the amount of intake air to the cylinder, mp (t ₀ ) is the amount of air flowing in from a path other than the throttle valve, and mt (t _{0) -} ) The amount of air passing through the throttle before the throttle valve operates.

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