JPH02211382A - Ignition timing controller for internal combustion engine - Google Patents

Abstract

PURPOSE:To improve drivability by dissolving the hunting in the ignition timing control during warming process by constituting an ignition timing control means so that the waiting period is changed according to the engine water temperature. CONSTITUTION:An ignition timing controller of an internal combustion engine is constituted of an ignition timing control means 3 which receives the outputs of an operation state detecting means 1 and a knock detecting means 2 and determines the ignition timing according to the operation state and delaying- angle-corrects the determined ignition timing when knock is detected and advance-angle-corrects the delayed angle ignition timing after the waiting for a prescribed time when knock is completed, and an igniting means which receives the output of the means 3 and ignites the mixed gas in an engine combustion chamber. An engine water temperature detecting means 3 for detecting the engine cooling water temperature is installed, and an ignition timing control means 3 is constituted so as to receive the output of the engine water temperature detecting means 5 and changes the waiting period according to the detected engine water temperature.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to an ignition timing control device for an internal combustion engine, and more specifically, to an ignition timing control device for an internal combustion engine in which the return correction after the end of knocking is changed according to the engine water temperature. This invention relates to a timing control device.

(Prior art) When knocking occurs in an internal combustion engine, it makes an abnormal noise that causes discomfort to the occupants. It is common practice to monitor and retard the ignition timing when knocking occurs, and after the knocking has stopped, to return the retarded ignition timing to the advanced side after waiting for an appropriate number of ignitions or an appropriate amount of time.
An example thereof is the technique described in Japanese Patent Publication No. 57-12027.

(Problem to be Solved by the Invention) By the way, in an internal combustion engine, the combustion condition is not good when the cooling water temperature is low. As a result, the difference (knock margin) between the set ignition timing and the ignition timing at which knock occurs (knock zone) is smaller than when warm-up is complete, and the warm-up is completed. The frequency of knocking tends to be higher when compared to the previous technology. Also, the lower the water temperature is, the more the advance angle correction amount is set, the above tendency becomes more pronounced. However, the above-mentioned conventional technology In this case, no special consideration is given to this point, and the waiting period is set uniformly before and after warming up, so knocking occurs frequently during the warming up process, causing ignition timing to advance or lag. There is a problem in that the angles are repeated, hunting occurs in ignition timing control, and drivability deteriorates.

Therefore, the present invention solves the above-mentioned drawbacks of the prior art, and provides an internal combustion engine that changes the standby period according to the engine water temperature, thereby eliminating hunting in ignition timing control during the warm-up process and improving drivability. The purpose of the present invention is to provide an ignition timing control device for an engine.

(Means for Solving the Problems) In order to achieve the above object, the invention described in claim 1 is directed to an operation that detects the operating state of the engine including at least the engine rotation speed and the engine load, as shown in FIG. State detection means l
, a knock detection means 2 that detects the occurrence of knock by detecting vibrations of the engine; the outputs of the knock detection means and the operating state detection means are inputted, the ignition timing is determined according to the operating state, and the knock is detected; The ignition timing control means 3 retards the determined ignition timing when the knocking stops, and waits for a predetermined period and advances the retarded ignition timing when the knocking stops.
and an ignition timing control device for an internal combustion engine comprising an ignition means 4 inputting the output of the ignition timing control means to ignite the air-fuel mixture in the engine combustion chamber, an engine water temperature detection means 5 for detecting the engine cooling water temperature is provided. The ignition timing control means inputs the output of the engine water temperature detection means and changes the standby period according to the detected engine water temperature.

Further, in the ignition timing control device for an internal combustion engine according to the second aspect, the waiting period is configured to be changed to become longer as the engine water temperature becomes lower.

(Function) The ignition timing control device for an internal combustion engine according to claim 1 is configured to change the standby period according to the engine water temperature, so even when the cold advance is set, the ignition timing control device for an internal combustion engine is configured to change the standby period according to the engine water temperature. Knocking is less likely to occur again during the engine process, and drivability is not deteriorated by frequently advancing or retarding the ignition timing. Specifically, as stated in claim 2, the waiting period is changed so that it becomes longer as the engine water temperature decreases, so that the advance angle correction is increased as the temperature decreases. Also, it is possible to effectively avoid deterioration of drivability due to advancement or retardation of the ignition timing.

(Example) The present invention will be described in detail below. FIG. 2 shows the overall configuration of an ignition timing control device for an internal combustion engine according to the present invention.
Referring to the figure, reference numeral 10 indicates a multi-cylinder internal combustion engine for a vehicle, which includes four cylinders or the like. The internal combustion engine 10 is equipped with an intake air passage 12, and the air flowing in from the air cleaner 14 is introduced into the combustion chamber 20 of the - cylinder after passing through the intake manifold while its flow rate is adjusted by a throttle valve 16. A pipe 24 is connected to the intake air passage 12 at an appropriate position downstream of the throttle valve 16 to branch off, and near the end of the branch passage there is an intake air passage that measures the pressure of the intake air in absolute value to detect the engine load. Pressure sensor 26
will be provided. Further, a water temperature sensor 30 serving as the engine water temperature detection means is provided near the cooling water passage 28 of the internal combustion engine 10 to detect the temperature of the engine cooling water, and is located at an appropriate position downstream of the throttle valve 16 in the intake air passage 12. An intake temperature sensor 32 is provided to detect the temperature of air taken into the engine.

Further, a distributor 36 is located near the internal combustion engine 10.
and a crank angle sensor consisting of a magnet that rotates in synchronization with the rotation of a crankshaft (not shown) that rotates as the piston 38 moves up and down, and a rotating body that is placed opposite the magnet. 40 is housed therein, and outputs a pulse signal at every predetermined crank angle. Further, a piezoelectric knock sensor 44 is provided at an appropriate position on the cylinder block 42 of the internal combustion engine 10 to detect vibrations caused by knocks generated from the combustion chamber 20. The output of the sensor 26.30, 32°40.44 such as the above-mentioned intake pressure sensor is
It is sent to the control unit 50.

FIG. 3 shows details of the control unit 50. To explain according to the figure, the outputs of the intake pressure sensor 26, water temperature sensor 30, and intake air temperature sensor 32 are inputted to a level conversion circuit 52 in the control unit to a predetermined level. After being converted into , it is input to the microcomputer 54 . The microcomputer includes an A/D conversion circuit 54a
, ■1054 b, CPU54 c, ROM54 d,
It is equipped with a RAM 54e, a calculation counter, and a timer (the counter and timer are not shown), and the output of the level conversion circuit is output from the A/D according to the command from the CPU 54c.
After being converted into a digital value in the conversion circuit 54a, R
The output of the crank angle sensor 40 is temporarily stored in the AM54e, and the output of the crank angle sensor 40 is waveform-shaped in the waveform shaping circuit 56, and then input into the microcomputer via the l1054b. After being sent to the control unit 50, it is input to the knock detection circuit 60. The knock detection circuit 60 includes filter means 60
a, comparator means 60b, and D/A conversion means 6
0c, and the filter means 60a has a comparator means 6
It is connected to the non-inverting input terminal of 0b, and its inverting input terminal is connected to the D/A conversion means 60c. Further, the comparator means 60b is connected to the microcomputer 54, and the microcomputer 54 is connected to the D/
It is connected to the A conversion means 60c. It should be noted that if a resonance type sensor that generates an output by resonating at a frequency based on the knock is used as the above-mentioned knock sensor 44, the filter means 60a becomes unnecessary as shown by the imaginary line.

In this knock detection circuit 60, the sensor output is sent to the microcomputer 5 in the comparator means 60b.
The noise level is calculated and knock is determined by comparing it with the reference value set by the microcomputer 54, and to explain this point with reference to the timing chart of FIG. In the angular range (for example, ATDC 120 to 140 degrees), the noise level, which is a background value of engine vibration, is output as a comparison reference value to the D/A conversion means 60c. This angular range is shown as "noise gate" in FIG. The output value is D
/A conversion means 60c converts it into an analog value, and compares it with the sensor output level by comparator means 60b. The microcomputer 54 changes this noise level based on the comparison result. The noise level is set to be approximately near the peak value of the sensor output level.

Further, the microcomputer 54 calculates a predetermined coefficient (appropriately set according to the operating condition) based on the noise level in an appropriate rank angle range (ATDCIO to 50 degrees) including the fuel condition shown as "knock gate" in FIG. The knock determination level is calculated by multiplying the knock determination level by the value of the knock determination value), and the calculated knock determination level is output to the comparator means 60b via the D/A conversion means 60c. The comparator means 60b compares the sensor output level with the knock determination level, and determines that a knock has occurred when the sensor output exceeds the knock determination level. Note that the calculation of the noise level and the knock judgment level in this knock detection method is performed in the microcomputer 54 using a software method, but it may also be detected in an analog manner using a hardware circuit (or Various methods may be used to generate the level, such as using an average value of sensor outputs.

As is well known, in the microcomputer, the CPU 54c calculates the engine speed from the output of the crank angle sensor 40, determines the engine load state from the output of the intake pressure sensor 26, and retrieves the basic ignition timing map stored in the ROM 54d. Calculates the basic ignition timing, corrects the basic ignition timing from other operating parameters such as water temperature and intake air temperature, and further corrects the advance/retardation of the ignition timing when there is a knock condition to calculate the final ignition timing. Then, an ignition device 70 consisting of an igniter or the like is commanded to ignite via the output circuit 68, and the spark plug 72 of a predetermined cylinder is ignited via the distributor 36 to ignite the air-fuel mixture in the combustion chamber 20.

Next, the operation of this control device will be explained with reference to the flow chart in FIG. Incidentally, the program shown in FIG. 5 is started by interruption in the microcomputer at every predetermined crank angle.

First, in S10, it is determined from the output of the knock detection circuit 60 described above whether or not a knock has occurred. In the flow chart, addition means correction in the retard direction, and subtraction means correction in the advance direction.This knock correction amount is added to the ignition timing control value as described above, and the final ignition timing is adjusted. Needless to say, the knock correction amount is determined at step 314, and it is determined whether the knock correction amount has reached the retardation upper limit value θRDLMT.
When the knock correction amount is reached, the knock correction amount is fixed at the upper limit value in step 316. Next, in S18, the counter CADV is reset to O, and in S20, the flag FADVT-
Reset to O. These counters and flags will be described later.

When it is determined in 310 that knocking has not occurred, the process proceeds to 322, where it is determined whether the knock correction amount θKN has returned to the upper limit value θADVLMT on the advance angle side, and when it is determined that it has not returned, the process proceeds to S24. Proceed to flag F AD
Determine whether VTW is set to 1. Note that when the knock correction amount θKN has returned to the advance angle upper limit value θADVLMT, θKN=θADVLMT is determined in S23.
Set to .

Therefore, at the first startup, the judgment at 324 is denied and the process goes to S26, where the detected water temperature T- is set to a predetermined value TwA.
The standby ignition number table ADVTW is searched in S28 and 330 according to the comparison result. Since the purpose of this predetermined value TwADV is to eliminate the inconvenience caused by setting the cold advance in the present invention, the predetermined value TwADV is a water temperature value suitable for determining whether or not warm-up is completed, for example, 65°C. shall be. When it is determined in S26 that warm-up is complete, proceed to 32B and ADV TW)
Select the I table and press S when it is determined that the warm-up process is in progress.
30 searches the ADVTWL table. FIG. 6 is an explanatory diagram showing this ADVTWH,L table, and this table is stored in the ROM 54 of the microcomputer mentioned above.
It is stored in d. In addition, as shown in the figure, the low temperature side (7) A
DVTWL is the non-low temperature side (7) ADVTW)! The standby ignition number ADVTW is set larger, and H, L2
Both table values are set so that they become thicker in proportion to the increase in engine speed.

Next, the process proceeds to step 332, where the flag F ADVT- is set to 1, and then, in step S34, a counter CADV, which counts the number of times this flow chart is looped, is incremented. The flag F ADVTW therefore indicates that the table value search has ended. Then, S36
The table value AD searched by the counter value CADV
It is determined whether the VTW has been reached, that is, whether the number of non-knock ignitions has reached the set number of standby ignitions. When the program is started for the first time, it is usually denied and the program is temporarily terminated.

When it is determined that the knock correction amount θKN has been reached at 336 when starting the program from next time onwards, the process proceeds to 338 and the knock correction amount θKN is corrected to the advance side by a predetermined amount Δθ. This is repeated until it is determined that the advance angle has returned to the upper limit value θADVLMT, and when it is confirmed that the advance angle has returned to the upper limit value θADVLMT, in S23 the knock correction amount is limited to the upper limit value, and then the counter CADV, 7 lag is The process ends by resetting FADVT- to 0.In addition, 33
The unit amount of return at 8 or the unit amount of retard at 312 may be set as appropriate, such as 1 degree of crank angle, and the return side and the retard side may be the same or may be different.

As described above, the ignition timing control device for an internal combustion engine according to the present embodiment sets the standby ignition number relatively large when the engine water temperature is low during the warm-up process compared to the number at the end of warm-up.
Even when cold advance is set, knocking is less likely to occur again, and therefore the ignition timing does not need to be frequently advanced or retarded, which has the advantage of improving drivability. In addition, since the low temperature waiting period is set to a large value, it is possible to effectively prevent the recurrence of knocking and improve drivability even when the cold advance is increased as the temperature decreases. I can do it. Although the standby period is expressed in terms of the number of ignitions, it goes without saying that time may also be used.

FIG. 7 shows a second embodiment of the present invention, and the differences from the first embodiment will be mainly explained. After the delay angle is corrected when a knock occurs, when the knock ends (S100 to 3114).
), SL 16 searches for the basic value ADV BASE of the standby ignition number according to the engine speed Ne and intake pressure Pba, 3118 searches for the modified value ADVTW according to the water temperature, and 5120 adds up the two. Final standby ignition number ADV
Determine. FIG. 8 is an explanatory diagram showing the basic value of the standby ignition number, which is searched according to the engine speed and intake pressure from the map values stored in the ROM as shown. Also, the 9th
The figure is a diagram for explaining the water temperature correction value ADVT-, which is searched according to the water temperature from table values in the ROM, which are set so that as the water temperature rises, the standby ignition number becomes shorter as shown in the figure. Note that the remaining steps (3122 to 312B) are similar to those in the first embodiment, so their explanation will be omitted.

In the case of the second embodiment, the effects and advantages are the same as those of the first embodiment, except that the number of standby ignitions is set variably depending on the load condition of the engine.

(Effect of the invention) In the ignition timing control device for an internal combustion engine according to claim 1,
An engine water temperature detection means is provided to detect the engine cooling water temperature,
The ignition timing control means inputs the output of the engine water temperature detection means and changes the standby period according to the detected engine water temperature, so even when cold advance is set, knocking does not occur at low temperatures. This does not occur frequently, and therefore the ignition timing is not frequently advanced or retarded, so drivability during the warm-up process can be greatly improved. Therefore, the waiting period is specifically changed as described in claim 2 (since the engine water temperature is configured to be longer as the engine water temperature is lower, the advance angle correction amount is set to be larger as the temperature is lower). Recurrence of knocking is effectively avoided even when the engine is warmed up, and drivability during the warm-up process can be significantly improved.

[Brief explanation of the drawing]

Fig. 1 is a diagram corresponding to the claims of the present invention, Fig. 2 is a schematic diagram of a control device according to the present invention, Fig. 3 is a block diagram showing details of the control unit, and Fig. 4 is a diagram of the knock detection circuit of the control unit. A timing chart showing the operation, FIG. 5 is a flow chart showing the operation of this device, and FIG. 6 is a flow chart showing the operation of the device.
FIG. 7 is a flow chart showing the second embodiment of the present invention; FIG. 8 is an explanatory diagram showing the basic characteristics of the number of standby ignitions in the chart, and FIG. The figure is an explanatory diagram showing correction characteristics depending on water temperature. ■... Driving condition detection means (intake pressure sensor 26, crank angle sensor 40), 2... Knock detection means (knock sensor 44, knock detection circuit 60, microcomputer 54), 3... Ignition timing Control means (microcomputer 54), 4... Ignition means (ignition device 70,
Disc l-IJ computer 36, spark plug 72), 5.
... Engine water temperature detection means (water temperature sensor 30), 50...
Control unit, 54... Microcomputer, 6
0...knock detection circuit applicant Honda Motor Co., Ltd. agent Patent attorney Yoshi 1) Toyodai! figure

Claims (2)

[Claims] (1) a. Operating state detection means for detecting the operating state of the engine including at least the engine speed and engine load; b. Knock detection means for detecting the occurrence of knock by detecting engine vibration; c. The knock detection. inputting the output of the means and the operating state detecting means, determining the ignition timing according to the operating state, retarding the determined ignition timing when knocking is detected, and retarding the determined ignition timing for a predetermined period when the knocking has ceased. Ignition timing control means for advancing the ignition timing that has been delayed in standby; and d. ignition means for inputting the output of the ignition timing control means to ignite the air-fuel mixture in the combustion chamber of the engine. The timing control device includes g, engine water temperature detection means for detecting the engine cooling water temperature, and the ignition timing control means inputs the output of the engine water temperature detection means and controls the standby according to the detected engine water temperature. An ignition timing control device for an internal combustion engine, characterized in that the period is changed. (2) The ignition timing control device for an internal combustion engine according to claim 1, wherein the standby period is changed to become longer as the engine water temperature becomes lower.