JPS63227959A - Ignition timing control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To avoid the situation in which a correction amount is transferred uniformly to a knocking control, by correcting the ignition timing being based on the correction amount in a more delay timing side of the MBT (minimum advance timing in the time of maximum torque) correction amount and the knocking correction amount when a knocking is in a predetermined level or more. CONSTITUTION:A knocking correction amount is calculated by the first arithmetic means (d) being based on an output of a knocking detecting means (a). While an MBT correction amount, correcting the ignition timing so that a crank angle maximizing an in-cylinder pressure of an engine detected by a pressure detecting means (b), that is, the in-cylinder maximum timing agrees with a target position maximizing generated torque of the engine, is calculated in the second arithmetic means (f). And the engine corrects the basic ignition timing, set in accordance with an engine operative condition, corresponding to the MBT correction amount while sets in a setting means (g) the ignition timing being based on the correction amount in more delay timing side of the knocking correction amount and the MBT correction amount when knocking is in a predetermined level or more, thus controlling an ignition means (h) on the basis of an output of said setting means (g).

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an ignition timing control device for an internal combustion engine such as an automobile, and more specifically, to an ignition timing control device for an internal combustion engine such as an automobile. The present invention relates to a device that improves drivability by performing the steps No. 11 and 11.

(Prior Art) The ignition timing of an internal combustion engine needs to be determined depending on the state of the engine so that the engine can be operated optimally.

Generally speaking, when considering engine efficiency and fuel consumption, the minimum advance angle at maximum torque, so-called M B T (Minimus +
ad-vance for Be5t Torque
), and the ignition timing is changed depending on the engine condition, so-called MBT.
'#Ii control is performed.

However, in certain engine conditions, advancing the ignition timing may cause knocking, making it impossible to operate the engine stably. Therefore, a system has been developed in which so-called knocking control, in which the ignition timing is controlled depending on the presence or absence of knocking, is used in combination with the above-mentioned MBTI1111II. There is a device.

In this device, the pressure inside the combustion chamber (hereinafter referred to as cylinder pressure)
is detected, and the ignition timing is adjusted so that the crank angle at which the pressure is maximum (hereinafter referred to as maximum cylinder pressure timing) θpmax is at a predetermined position that maximizes the torque generated by the engine.
i#]m. At the same time, all knocking is detected by passing the in-cylinder pressure detection signal through a signal processing circuit, and when the knocking level exceeds a predetermined value, it takes priority over MBT control and retards the ignition timing to avoid knocking. Control. When knocking is suppressed, the ignition timing is changed again to MBTt.
llJ to maximize the torque generated by the engine. This is intended to increase the torque generated by the engine as much as possible while suppressing knocking, thereby improving driving performance.

(Problems to be Solved by the Invention) However, in such conventional ignition timing control devices for internal combustion engines, switching between knock control and MBT control is determined only by the presence or absence of knock, and knock does not occur. Then, since the configuration was such that knock control was given priority over MBT control at any time, MBTI
When the ignition timing correction amount by ll'm is smaller than the retardation correction amount for knock control (that is, when the ignition timing by MBT control is on the retard side than the ignition timing by knock control), if MBT control is performed, Even if knock suppression can be achieved without switching to knock control, if knock occurs, the system will unconditionally shift to knock control, making it impossible to improve fuel efficiency or power performance during this period. Ta. In other words, when the ignition timing under MBT11 control is more retarded than the ignition timing under knock control, the MBT
*If J control is selected, it is possible to improve fuel efficiency and output while suppressing the occurrence of knock, but with conventional devices, when knock occurs, priority is always given to knock control, resulting in lower fuel efficiency and output. There seems to be room for improvement in this respect.

(Object of the Invention) Therefore, the present invention corrects the ignition timing based on the more retarded correction amount of the knock correction amount and the MBT correction amount when knock occurs.
The purpose of this is to avoid the situation where the ignition timing is retarded than the ignition timing caused by the knock control, and to improve the fuel efficiency and driving performance of the engine by effectively controlling the MBTwI by avoiding the situation where the ignition timing is retarded than the ignition timing caused by the knock control. It is said that

(Means for Solving the Problems) In order to achieve the above object, the ignition timing control device for an internal combustion engine according to the present invention includes a knock detection means a for detecting knocking occurring in the engine, and a pressure detection means for detecting the cylinder pressure of the engine. The detection means includes an operation state detection means C that detects the operating state of the engine, and a first one that calculates a knock correction amount that corrects the ignition timing so as to suppress knocking to a predetermined level based on the output of the knock detection means a. Maximum timing detection means e for detecting the crank angle at which the cylinder pressure is maximum as the cylinder pressure maximum timing based on the outputs of the calculation means d and the pressure detection means S.
and an MBT that corrects the ignition timing so that the maximum cylinder pressure timing matches the target position where the engine generates the maximum torque.
A second calculation means f that calculates the correction amount and sets the basic ignition timing based on the operating state of the engine, and sets the basic ignition timing based on the MBT.
an ignition timing setting means g that corrects the ignition timing according to the correction amount and also corrects the ignition timing based on a correction amount on the retard side of the knock correction amount and the MBT correction amount when the knocking is at a predetermined level or more; and ignition means for igniting the air-fuel mixture based on the output of the setting means g.

(Operation) In the present invention, the knock correction amount and the MBT correction amount are calculated, and when a knock occurs, the ignition timing is corrected based on the correction amount on the retard side of the knock correction amount and the MBT correction amount. Therefore, even if the ignition timing under MBT control is on the retarded side than the ignition timing under knock control, a situation in which the ignition timing is uniformly shifted to knock control is avoided, and MBr[?
11 will improve the fuel efficiency and driving performance of the engine.

(Example) Hereinafter, the present invention will be explained based on the drawings.

2 to 7 are diagrams showing an embodiment of the present invention.

First, the configuration will be explained. In FIG. 2, 1a to 1f are cylinder pressure sensors (pressure detection means), and cylinder pressure sensor 1
A to 1f convert the in-cylinder pressure in each cylinder (six cylinders in this embodiment) into an electric charge using a piezoelectric element, and output a charge signal S+-3i. The outputs S1 to S of the cylinder pressure sensors 1a to 1f are input to the knock detection means 2, and the knock detection means 2
is a multiplexer (MPX>3, input amplifier 4, bandpass filter (BPF) 5 and peak hold circuit 6
Consisted of. Signals S, ~S6 are multiplexer 3
A switching signal Sc from a microcomputer 7, which will be described later, is further input to the multiplexer 3 at a predetermined timing.

Every time this switching signal Sc is input, the multiplexer 3 changes the outputs of the cylinder pressure sensors 1a to 1f to S, -Ss -3s
-3h -3z → S4 is switched in the order and inputted to the input amplifier 4. The input amplifier 4 amplifies these signals and outputs them as a signal S to the band pass filter 5, and the band pass filter 5 passes only the signal S in the frequency band corresponding to the knock vibration out of the signal S and removes the peak. Hold circuit 6
Output to.

The peak hold circuit 6 holds the maximum amplitude value (peak value) of the signal S, and outputs it to the microcomputer 7 as a value corresponding to knock energy. This peak hold processing is performed based on a peak hold set/reset signal from the microcomputer 7, and includes, for example, an area where knocking is expected to occur (TD
C-ATDC approximately 50°). The peak hold value is used as data for detecting the level of noaking. Note that the holding of the peak value is not limited to the peak hold circuit 6, and may be performed using, for example, a rectifying integrator.Furthermore, the intake air flow rate Qa is detected by the air flow meter 8, and the engine crank angle is detected by the crank angle. It is detected by the angle sensor 9. The crank angle sensor 9 detects the compression top dead center (TDC) of each cylinder at every explosion interval (120° for a 6-cylinder engine, 180° for a 4-cylinder engine).
At a previous predetermined position, for example, B T D C70'' (while outputting a reference signal Ca that becomes a Hl level pulse,
A unit signal CI that becomes an (H) level pulse is output for each unit angle (for example, 1°) of the crank angle. Note that by counting the pulses of the signal Ca, the engine rotation speed N
can be known.

The air flow meter 8 and the crank angle sensor 9 constitute an operating state detecting means 10, and the outputs of the operating state detecting means 10, the input amplifier 4, and the peak hold circuit 6 are input to the microcomputer 7. The microcomputer 7 performs ignition timing control based on this information. The microcomputer 7 has functions as a first calculation means, a maximum timing detection means, a second calculation means, and an ignition timing setting means, and includes a CPU II, a ROM 12, a RAM 13,
It is composed of an A/D converter 14 and an I10 interface 15, which are connected to each other by a common bus 16. The A/D converter 14 converts Qa, etc. input as an analog signal into a digital signal, and converts it into a digital signal.
ROM12 or RAM at the specified time according to the instructions.
Output to 13. The CP Ull takes in necessary external data according to the program written in the ROM 12, and while exchanging data with the RAM 13, calculates processing values necessary for knock suppression control and MBTiii control. The processed data is output to the I10 interface 15 as necessary. Signals from various sensors are input to the I10 interface 15, and the I10 interface 15 outputs a switching signal Sc to the multiplexer 3, a peak hold set/reset signal to the peak hold circuit 6, and an ignition signal Sp. is output to the ignition means 16. R
The OM 12 stores calculation programs for the CPU Ull, and the RAM 13 stores data used in calculations in the form of a map or the like. The ignition signal Sp is input to the ignition means 17, and the ignition signal 17 is composed of a spark plug, an ignition coil, a distributor, etc.
A high pressure pulse is generated based on p and ignites the air-fuel mixture.

Next, the effect will be explained.

FIG. 3 is a flowchart showing an ignition timing control program, and this program is executed once every predetermined period. First, in PI, engine speed N and engine load (
In addition to using the intake air amount Qa as data, for example, data based on load sensor output such as throttle valve opening or intake pipe internal pressure may also be used)
Basic ignition timing A from the table map with parameters
Look up DVφ and calculate MBT correction amount γ for performing MBTIII# in P2. The MBT control control amount takes a value as shown in FIG. 4 depending on the cylinder pressure maximum timing θpa+axO value. Here, K is the target position of MBT control, and is set to a predetermined value in the crank angle that maximizes the torque generated by the engine, for example, in the range of ATDCIO° to 20'' (in this example, it is set to -15°). ).The calculation of the MBT correction amount γ will be explained in detail later in FIG. The detected knocking level is compared with a value exceeding a frequency of about 10% to determine whether or not knocking has occurred, and based on the determination result, the knock correction amount β is determined by the calculation formula described later using the method described in FIG. 7, which will be described later. There is also a method in which the knock correction amount β takes a value as shown in FIG. Calculate the quantity FB.

FB-FB' +min (7, β> ・------・■
However, FB': Previous value m1n (r, β): MBT correction amount γ or knock correction amount β, whichever corrects the ignition timing to the retarded side. Therefore, in steps P2 and P3 above, each is independent. Of the MBT correction amount γ or the knock correction amount β calculated in The switching state is avoided, and M
Even when the BT correction amount is smaller than the knock correction amount β (that is, the ignition timing under MBTIJ control is on the retarded side than the ignition timing under knock control), MBT\VH8 can be maintained.

Next, the final ignition timing ADV is determined at P according to the following formula.

ADV=ADVφ10FB ・・・・・・■And P,
Based on this ADv, (70''-ADV) is sent to the register of the ■/○ interface 15, the ignition signal Sp is output at a predetermined ignition timing, and the current process ends.

FIG. 6 is a flowchart showing a subroutine for MBT control, which corresponds to step P2 described in FIG. 3 above. First, the current MBT correction r s according to the 0 formula at pH
Find tew.

However, γ. 4. : Previous value M : Constant K of 1 or more : Target position Next, the MBT correction amount is within the range regulated by the force angle limit value (for example, +10°) and the retardation limit value (for example, -10°) at pH. If it is not within this range, the current γ is limited to one of the respective limit values, and if it is within this range, that value is adopted as γ. In this way, M
The BT correction amount γ is 10 around the target position K as shown in FIG.

is calculated within the range of , and feedback control that follows the so-called target is performed. Note that since the detection of θpmax is conventionally well known, a detailed explanation will be omitted here.

FIG. 7 is a flowchart showing a knock control subroutine, which corresponds to step P described in FIG. 3 above. First, knocking level data X is compared with reference value Xo using pz+. When X>XO, it is determined that knocking has occurred and the ignition timing is retarded, so the current knock correction amount βi1 is determined in accordance with the following equation (2) at Ptt.

β□0−β. , 4-δ1...■However, β.

Ld: Previous value δ1: Retard angle correction amount On the other hand, when x: 5xo, it is determined that knocking has been suppressed and the ignition timing is advanced, so δ7.1 is determined at Pt3 according to the following equation (2).

β, , 8−β. , 4+δ2 ...■ However, δ
t: Advance angle correction amount In this way, the ignition timing is corrected depending on whether or not knocking occurs. At this time, the retard angle correction is δ1 (for example, 1°
CA unit), and the advance angle correction is made more gradually by δ
Next, the knock correction amount β is regulated by the advance angle limit value [0°] and the retard angle limit value (for example, -10''') at Pta. It is checked whether it is within the range, and if it is not within this range, the current β is limited to one of the respective limit values, and if it is within this range, that value is adopted as β.

In this way, the MBT correction 1r and the knock correction amount β are calculated, and when a knock occurs, the ignition timing is corrected based on the more retarded correction amount of the upper MBT correction amount and the knock correction amount β. Therefore, even if a knock occurs, the MB
It is possible to avoid a situation where the T control is uniformly shifted to the knock control, and it is possible to perform MBT@@ as much as possible to improve fuel efficiency and output.

(Effect) According to the present invention, when knock occurs, the ignition timing is corrected based on the more retarded correction amount of the knock correction amount and the MBT correction amount, so that the ignition timing by MBT control is the same as the ignition timing by knock control. MBT avoids the situation where knock control is uniformly applied even when the timing is on the retarded side.
The i#I control can be made more effective, and the fuel efficiency and driving performance of the engine can be improved.

[Brief explanation of the drawing]

FIG. 1 is a basic conceptual diagram of the present invention, FIGS. 2 to 7 are diagrams showing an embodiment of an ignition timing control device for an internal combustion engine according to the present invention, FIG. 2 is an overall configuration diagram thereof, and FIG. is a flowchart showing the ignition timing control program, and Fig. 4 is the flowchart showing the ignition timing control program.
A characteristic diagram of the BT correction amount, FIG. 5 is a characteristic diagram of the knock correction amount, FIG. 6 is a diagram showing a subroutine for calculating the MBT correction amount, and FIG. 7 is a diagram showing a subroutine for calculating the knock correction amount. It is. 1a to 1f...Cylinder pressure sensor (pressure detection means)
2...Knock detection means, 7...Microcomputer (first calculation means,
Maximum timing detection means, second calculation means, ignition timing setting means), 10... Operating state detection means, 17... Ignition means. Figure 3 Figure 4 Figure 5 Figure 6 Figure 7

Claims (1)

[Scope of Claims] a) Knock detection means for detecting knocking occurring in the engine; b) Pressure detection means for detecting the cylinder pressure of the engine; c) Operating state detection means for detecting the operating state of the engine. d) a first calculation means for calculating a knock correction amount for correcting the ignition timing so as to suppress knocking to a predetermined level based on the output of the knock detection means; and e) a first calculation means for calculating the in-cylinder pressure based on the output of the pressure detection means. f) a maximum timing detection means for detecting the crank angle at which the cylinder pressure is at its maximum as the maximum cylinder pressure timing;
a second calculating means for calculating a correction amount; g) setting a basic ignition timing based on the operating state of the engine, correcting it according to the MBT correction amount, and adjusting the knock correction when knocking is at a predetermined level or higher; h) ignition timing setting means for correcting the ignition timing based on a correction amount on the retard side of the amount and the MBT correction amount; and h) ignition means for igniting the air-fuel mixture based on the output of the ignition timing setting means. An ignition timing control device for an internal combustion engine, characterized in that: