JP2004360562A - Control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for an internal combustion engine capable of taking a knocking countermeasures without deteriorating output torque and fuel economy of an internal combustion engine. <P>SOLUTION: This device is provided with the internal combustion engine 1 having a plurality of cylinders 1a - 1d, an intake air quantity control means 7a - 7d individually controlling intake air to each cylinder 1a - 1d of the internal combustion engine 1, a fuel injection means 9a - 9d individually controlling fuel injection quantity to each cylinder 1a - 1d of the internal combustion engine 1, a knocking detection means 13 detecting knocking of the internal combustion engine for each cylinder, and a control means 14 controlling intake air quantity of each cylinder by the intake air control means 7a - 7d and fuel injection quantity corresponding to intake air quantity by the fuel injection means 9a - 9d. In this device, the knocking detection means 14 detects knocking, the control means 14 performs control to reduce intake air quantity of the cylinder where knocking occurs. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a knocking control of a vehicular internal combustion engine, and more particularly to a control device of an internal combustion engine that performs knocking control while reducing fuel consumption.
[0002]
[Prior art]
In a vehicle internal combustion engine, particularly an internal combustion engine having supercharging or an internal combustion engine having a high compression ratio, knocking occurs during high load operation of the internal combustion engine. The temperature boundary layer that protects the wall surface from the high-temperature combustion gas is destroyed, which may lead to an accident that the components constituting the combustion chamber are melted and damaged. For this reason, when knocking occurs, knocking control that detects knocking vibration occurring in the internal combustion engine and retards the ignition timing according to a signal of the knocking vibration is generally performed.
[0003]
On the other hand, the internal combustion engine has an optimum ignition timing called MBT (Minimum Advanced for Best Torque), and the generated torque of the internal combustion engine decreases even if the ignition timing is advanced or retarded from this MBT. At the same time, fuel economy deteriorates. Therefore, the ignition timing is usually set at or near the MBT, but in the conventional internal combustion engine, when knocking occurs, the retard control is performed, so that the fuel efficiency of the cylinder on which the retard control is performed deteriorates. Will do.
[0004]
As a technique for reducing such adverse effects, for example, there is a technique disclosed in Patent Document 1. The technique disclosed in this document is based on a knock margin which is a difference between a maximum ignition angle (timing) at which knocking occurs in the present operating state of the internal combustion engine and an actual ignition angle in a state where the engine is retarded by knocking. Angle determination means for determining the angle of advance, advance angle setting means for setting the advance angle larger as the knock margin angle is larger, and ignition timing control means for advancing the actual ignition timing by the angle set by the advance angle setting means With this arrangement, the actual ignition timing delayed by knocking is made to quickly approach the MBT.
[0005]
[Patent Document 1]
JP-A-8-165974 (page 3, page 4, FIGS. 1 to 5)
[0006]
[Problems to be solved by the invention]
As described above, even if the ignition timing approaches the MBT quickly, the ignition timing is delayed along with the occurrence of knocking, and during a period outside the MBT region, torque decreases and fuel consumption deteriorates, and knocking occurs. In a use state in which the ignition occurs, if the ignition timing returns to the vicinity of the MBT, knocking occurs again, and as a result, the retard and the advance are repeated, so that the retard control is performed as a whole, For a cylinder that has been subjected to retard control, a decrease in torque and a deterioration in fuel economy are inevitable.
[0007]
The present invention has been made in order to solve such a problem, and has focused on the fact that knocking can be prevented even by controlling the amount of intake air to a cylinder in addition to retarding the ignition timing. An object of the present invention is to provide a control device for an internal combustion engine capable of taking measures against knocking without reducing fuel consumption.
[0008]
[Means for Solving the Problems]
A control device for an internal combustion engine according to the present invention includes: an internal combustion engine having a plurality of cylinders; intake air amount control means for individually controlling intake air for each cylinder of the internal combustion engine; and individually controlling a fuel injection amount for each cylinder of the internal combustion engine. A fuel injection means, a knock detection means for detecting knocking of each cylinder of the internal combustion engine, an individual intake amount of each cylinder by an intake amount control means, and a fuel injection amount corresponding to the intake amount by the fuel injection means. The knocking detection means detects knocking, and the control means controls the cylinder in which knocking has occurred to reduce the intake air amount.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiment 1 FIG.
FIG. 1 is a system configuration diagram of an internal combustion engine illustrating a control device for an internal combustion engine according to a first embodiment of the present invention, and FIG. 2 is a characteristic diagram showing an average effective pressure and fuel consumption in the vicinity of MBT. In FIG. 1, a four-cylinder internal combustion engine will be described as an example.
[0010]
In FIG. 1, an internal combustion engine 1 has cylinders 1a to 1d having a high compression ratio, and each cylinder 1a to 1d is provided with intake valves 2a to 2d and exhaust valves 3a to 3d. The intake valves 2a to 2d are provided at the connecting portions between the cylinders 1a to 1d and the intake branch pipes 4a to 4d, and the intake branch pipes 4a to 4d are integrated into one at the upstream portion to connect the intake pipe 5 to the intake pipes. The intake pipe 5 is connected to an air cleaner 6 to distribute intake air from the air cleaner 6 from the intake pipe 5 to each of the intake branch pipes 4a to 4d and to supply the intake branch pipes 4a to 4d to the cylinders 1a to 1d.
[0011]
The intake branch pipes 4a to 4d are provided with electronically controlled throttle valves (hereinafter referred to as ETVs) 7a to 7d as intake amount control means, intake pressure sensors 8a to 8d, and fuel injection valves 9a to 9d. , ETVs 7a to 7d individually control the intake air amount of each cylinder 1a to 1d. The intake pressure sensors 8a to 8d can be provided with a single intake pressure sensor and can be switched according to the stroke of each cylinder 1a to 1d. Exhaust valves 3a to 3d are provided at the connection between the cylinders 1a to 1d and the exhaust pipe 10. The exhaust pipe 10 is provided with an air-fuel ratio sensor 11 for detecting the air-fuel ratio of the internal combustion engine 1.
[0012]
The internal combustion engine 1 is provided with a cylinder identification sensor 12 capable of detecting the stroke and the rotational speed of each of the cylinders 1a to 1d, and a knocking detection means 13 for detecting a knocking signal. The signal output from knocking detection means 13 is input to control means 14. The control means 14 operates the ETVs 7a to 7d to individually adjust the intake air quantity of each of the cylinders 1a to 1d in the internal combustion engine 1, and the fuel injection valves 9a to 9d to operate the fuel injection. Individual fuel injection amount adjusting means 14b for individually adjusting the amount is included.
[0013]
The control means 14 calculates the amount of intake air for each of the cylinders 1a to 1d based on the operation amount of an accelerator pedal (not shown) operated by the driver and controls the ETVs 7a to 7d. After detection at 8a to 8d and identification of the cylinder by the cylinder identification sensor 12, the fuel injection amount for each cylinder is instructed to the fuel injection valves 9a to 9d. The individual intake air amount adjusting means 14a performs feedback control based on a signal from an air-fuel ratio sensor 11 provided in the exhaust pipe 10 to adjust the air-fuel ratio of each of the cylinders 1a to 1d.
[0014]
The control unit 14 has an ignition timing control unit (not shown), and controls the MTB or the vicinity of the MTB by controlling the ignition timing control unit with the output of the individual fuel injection amount adjusting unit 14b. FIG. 2 shows the effect of ignition at or near the MTB. The average effective pressure becomes maximum as shown by the curve (a) in the figure, and the ignition by the MTB as shown by the curve (b) in the figure. The fuel consumption will show the lowest value. That is, by performing ignition with MTB, the internal combustion engine 1 can be operated with the highest efficiency.
[0015]
In the internal combustion engine 1 configured as described above, when the knocking detection unit 13 detects a knocking signal during operation, the individual intake air amount adjustment unit 14a of the control unit 14 sends a command to the ETVs 7a to 7d to operate the ETVs 7a to 7d. The individual fuel injection amount adjusting means 14b controls the fuel injection amount of the corresponding cylinder to maintain the air-fuel ratio at a predetermined value based on this control. Control is performed to suppress knocking by reducing the amount of air and the amount of fuel.
[0016]
The occurrence of knocking is in the combustion stroke in a four-cycle internal combustion engine.To detect the occurrence of knocking and suppress knocking in the next combustion stroke, the amount of intake air in the next combustion stroke, or Although it is necessary to control the ignition timing, in the conventional internal combustion engine, the volume from the throttle valve to each cylinder becomes large because the throttle valve is present in the united intake pipe 5, and the throttle valve It is difficult to respond quickly to the control of the intake air amount even if the operation is accelerated, and the output of the internal combustion engine is reduced due to the decrease in the intake air amount of all cylinders. The timing was controlled by the retard control.
[0017]
In the control device for an internal combustion engine according to the present invention, the ETVs 7a to 7d are provided in the intake branch pipes 4a to 4d, respectively, and the intake control is performed independently for each cylinder. The knocking control can be performed with good responsiveness by the intake control. For example, even if the volume of each of the intake valves 2a to 2d on the downstream side of the ETVs 7a to 7d is 1.5 times the stroke volume of each of the cylinders 1a to 1d. If the ETVs 7a to 7d are closed before the intake valves 2a to 2d are opened, the intake air amount can be reduced to about 60% or less, knocking can be suppressed with sufficient responsiveness, and knocking does not occur. The output of the cylinder can be maintained.
[0018]
Further, by controlling the amount of decrease in the amount of air charged to the knocking-occurring cylinder in accordance with the signal intensity of the knocking detection means 13, knocking control can be performed without excessively reducing the output of the cylinder. If the return of the filling air amount is performed at once with the stop, a hunting phenomenon occurs between the occurrence of knocking and the stop.Therefore, by gradually increasing the return of the filling air amount with the rotation, hunting does not occur and fuel efficiency is maintained. Knocking can be effectively suppressed.
[0019]
Embodiment 2 FIG.
FIG. 3 is a system configuration diagram of an internal combustion engine illustrating a control apparatus for an internal combustion engine according to a second embodiment of the present invention. In FIG. The control device of the engine changes to the ETVs 7a to 7d with respect to the first embodiment, controls the amount of intake air by the opening period and the opening timing of the intake valves 15a to 15d, and adds an air flow sensor to the intake pipe 5. 16 are provided.
[0020]
The intake valves 15a to 15d are electronically controlled in valve opening period and valve opening timing or valve opening operation amount. For example, electronic direct acting valve control means and the like are used, and the intake valves 15a to 15d are interlocked with an accelerator pedal (not shown). In addition to controlling the amount of intake air, the amount of intake air is also controlled by a signal from knocking detection means 13. With this configuration, the control device 14 controls the electronic direct-acting valve control means used for the intake valves 15a to 15d, so that the charged intake air amount for each cylinder can be individually and rapidly performed. In addition, the ignition timing is set at the best timing of fuel efficiency irrespective of knocking, and knocking control can be performed with good responsiveness by intake control.
[0021]
Embodiment 3 FIG.
FIG. 4 is a system configuration diagram of an internal combustion engine illustrating a control apparatus for an internal combustion engine according to a third embodiment of the present invention. In FIG. The engine control device is provided with in-cylinder pressure sensors 17a to 17d with respect to the first embodiment, and functions of the intake pressure sensors 8a to 8d, the knocking detection means 13, and the cylinder identification sensor 12 are provided by the in-cylinder pressure sensors 17a to 17d. Some are replaced.
[0022]
Even in such a configuration, the cylinder pressure sensors 17a to 17d can detect the intake pressure and the knocking, and the stroke of each cylinder can be determined. Therefore, similarly to the first and second embodiments, the charging of each cylinder is performed. In addition to being able to perform the intake air amount individually and at a high speed, the ignition timing is set to the best timing of fuel efficiency irrespective of knocking, and knocking control can be performed with good responsiveness by intake control.
[0023]
【The invention's effect】
As described above, according to the control apparatus for an internal combustion engine of the present invention, the intake air amount control means for individually controlling the intake air for each cylinder of the internal combustion engine having a plurality of cylinders, and the fuel injection amount for each cylinder individually A fuel injection means, a knock detection means for detecting knocking of each cylinder, an intake air amount for each cylinder by the intake air amount control means, and a control means for controlling the fuel injection amount by the fuel injection means, When the knocking detecting means detects the knocking, the control means reduces the intake air amount for the cylinder in which the knocking has occurred. To control the knocking with good responsiveness, to obtain a control device for an internal combustion engine having good fuel consumption and good responsiveness to knocking. One in which it is bet.
[Brief description of the drawings]
FIG. 1 is a system configuration diagram illustrating a control device for an internal combustion engine according to a first embodiment of the present invention.
FIG. 2 is a characteristic diagram illustrating a control device for an internal combustion engine according to Embodiment 1 of the present invention.
FIG. 3 is a system configuration diagram illustrating a control device for an internal combustion engine according to a second embodiment of the present invention.
FIG. 4 is a system configuration diagram illustrating a control device for an internal combustion engine according to a third embodiment of the present invention.
[Explanation of symbols]
1 internal combustion engine, 1a-1d each cylinder,
2a-2d, 15a-15d intake valve, 3a-3d exhaust valve,
4a to 4d intake branch pipe, 5 intake pipe, 6 air cleaner,
7a-7d ETV (intake air amount control means), 8a-8d intake pressure sensor,
9a to 9d fuel injection valve, 10 exhaust pipe, 11 air-fuel ratio sensor,
12 cylinder identification sensor, 13 knocking detection means,
14 control means, 14a individual intake air amount adjusting means,
14b individual fuel injection amount adjusting means, 16 air flow sensor,
17a-17d In-cylinder pressure sensor.

Claims (7)

An internal combustion engine having a plurality of cylinders, an intake air amount control means for individually controlling intake air for each cylinder of the internal combustion engine, a fuel injection means for individually controlling a fuel injection amount for each cylinder of the internal combustion engine, Knocking detection means for detecting knocking of a cylinder, control means for controlling an individual intake amount of each cylinder by the intake amount control means, and a fuel injection amount corresponding to the intake amount by the fuel injection means; A control device for an internal combustion engine, characterized in that when the means detects knocking, the control means controls the cylinder in which knocking has occurred so as to reduce the intake air amount. 2. The control device for an internal combustion engine according to claim 1, wherein the control unit controls the intake air amount control unit in accordance with knocking intensity to change an intake air amount for a cylinder in which knocking has occurred. 3. The control device for an internal combustion engine according to claim 1, wherein the control unit gradually increases the intake air amount to the cylinder in which knocking has disappeared when the knocking detection unit stops detecting knocking. 4. The control device for an internal combustion engine according to claim 1, wherein the intake air amount control unit is provided in an intake branch pipe that distributes intake air to each cylinder of the internal combustion engine. 5. The volume between the intake amount control means provided in the intake branch pipe and the intake valve of each cylinder is 1.5 times or less the stroke volume of each cylinder. Internal combustion engine control device. 4. The control device for an internal combustion engine according to claim 1, wherein an individual intake amount of each cylinder is controlled by an opening / closing period or a valve operating amount of an intake valve provided in each cylinder. 5. 7. The control device for an internal combustion engine according to claim 1, wherein an in-cylinder pressure sensor is provided for each cylinder, and knocking is detected by the in-cylinder pressure sensor.

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