JPH02308970A - Ignition timing control device - Google Patents

Abstract

PURPOSE:To maintain driveability by using a data table determining the ignition timing based on the load and rotating speed in advance, and controlling the operation of an ignition coil to the ignition timing corresponding to the rotating speed while the load is assumed as fixed when a load detecting means fails. CONSTITUTION:A control means 21 is inputted with the load detected by an AN detecting means 20 based on the signal of an air flow sensor 13 and the rotating speed signal and the rotating speed signal from a crank angle sensor 17 and controls the operation of an ignition coil 19 to have the corresponding ignition timing by referring to a data table in which the ignition timing is set based on the load and rotating speed as parameters in advance. When a failure occurs in the AN detecting means 20, the control means 21 assumes the load as fixed and controls the operation of the ignition coil 19 to the ignition timing corresponding to the rotating speed. Driveability can be satisfactorily controlled even when the load detecting means fails.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ignition timing control device for an engine.

[Conventional technology]

In conventional ignition timing control devices, an airflow sensor detects the intake air amount of the engine, calculates the load from this intake air amount and rotation speed, and controls the ignition timing based on this load and rotation speed. It is being said. Here, when the load cannot be detected due to a disconnection of a connecting wire of the air flow sensor, etc., the ignition timing is fixed at a predetermined timing.

[Problem to be solved by the invention]

However, when the ignition timing is fixed as described above, drivability naturally deteriorates and knocking occurs, resulting in poor quality.

This invention was made to solve the above-mentioned problems, and an object thereof is to obtain an ignition timing control device that can adjust the ignition timing to 111111 with good operability even when the load detection means fails. .

(Means for Solving the Problems) The ignition timing control device according to the present invention includes a storage means for storing the ignition timing according to the engine load and rotation speed as a data table, and a failure detection means for detecting a failure of the load detection means. and control means for fixing the load and controlling the ignition timing based on the data table and the rotational speed when the load detection means fails.

[For production]

In this invention, when the load detection means fails, the load is kept at a fixed value and the ignition timing is varied according to changes in the rotational speed.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. 1st
The figure shows the configuration of the ignition timing control device, l is the engine, 1
0 is an air cleaner provided on the upstream side of the AFS C Karman vortex air flow sensor) 13 that detects the amount of intake air; 1
1 is a surge tank, 12 is a throttle valve, 14 is an injector, 15 is an intake pipe, and 16 is an exhaust pipe. AF
S13 outputs a pulse according to the amount of air taken into the engine 1, and the crank angle sensor 17 outputs a pulse according to the rotation of the engine 1 (for example, the crank angle is 180 degrees from the rise of the pulse to the next rise. ) is output. 20
is an AN detection means that counts the number of output pulses of the AFS 13 that fall between a predetermined crank angle of the engine 1 based on the output of the AFS 13 and the output of the crank angle sensor 17. 24 is a throttle opening sensor attached to the thrower I/Leharbe 12, which detects the throttle opening. 21 is a control means, the output of the ANiN detection means 20, the atmospheric pressure sensor 24,
The output of the water temperature sensor 18 (for example, a thermistor) that detects the cooling water temperature of the engine 1 and the output of the crank angle sensor 17 that detects the rotation speed of the engine 1 are input, and the driving time of the injector 14 and the energization of the ignition coil 19 are controlled. ,
This controls the amount of fuel supplied to the engine 1 and the ignition timing.

Further, the ignition coil 19 supplies its output voltage to the ignition plug 23 via the power distributor 22 to perform ignition.

FIG. 2 shows a more specific configuration of this embodiment, and 30 is A.
A control device that receives the outputs of the FS 13, crank angle sensor 17, water temperature sensor 18, and throttle opening sensor 24 and controls the four injectors 14 and ignition coil 19 provided for each cylinder of the engine 1; It corresponds to the N detection means 20 and the control means 21, and the ROM 41, R
Microcomputer (CPU) 40 with AM42
It is composed of etc. Further, 31 is a 2-frequency divider connected to the output of the AFS 13, and 32 is an exclusive OR gate with one input of the output of the 2-frequency divider 31 and the other input connected to the output P of the CPU 40. , its output is connected to the counter 33 and inputs P and l of the CPU 40. 34 is an interface connected between the water temperature sensor 18 and the A/D converter 35, and the output of the A/D″:1 inverter 35 is C
It is input to PU40. 36 is a waveform shaping circuit, into which the output of the crank angle sensor 17 is input, and its output is sent to the CPU 4.
0 is input to the interrupt human power P4 and the counter 37.

The output of the counter 37 is also input to the CPU 40.

38 is a timer connected to the interrupt P of the CPU 40;
39 is an A/D converter that A/D converts the battery voltage ■8 and inputs it to the CPU 40; 50 is an A/D converter that A/D converts the output of the throttle opening sensor 24 and inputs it to the CPtJ 40; 43 is the CPU 40 and the driver 44, and the output of the driver 44 is connected to each injector 14. Reference numeral 45 denotes an interface to which the output of the crank angle sensor 17 is input, and inputs a 1 degree signal of the crank angle to timers 46 and 47. timer 47
The output of the waveform shaping circuit 36 and the output of the CPU 40 are also input, and the outputs are input to the reset terminals of the timer 46 and the DF/F 48. The output of the CPU 40 is also input to the timer 46, and the output is input to the set terminal of the DF/F 48.

The output of D-F/F 4 B is input to the ignition coil 19 via the driver 49 .

Next, the operation of the above configuration will be explained. The output of the AFS 13 is frequency-divided by a two-frequency divider 31 and input to a counter 33 via an exclusive OR gate 32 controlled by the CPU 40. Counter 33 measures the period between falling edges of gate 32's output. The CPU 40 interrupts the falling edge of the gate 32 by the human power P3, performs interrupt processing every time the output pulse period of the AFS 13 or the frequency is divided by two, and measures the period of the counter 33. Also, it is converted into a voltage by the interface 34 of the water temperature sensor 18, and converted into a digital value by the A/D converter 35 at predetermined time intervals.
It is taken into PU40. The output of the crank angle sensor 17 is transmitted via the waveform shaping circuit 36 (,
, the timer 47 and the counter 37 are manually operated. CPlJ
40 performs an interrupt process every time the output of the crank angle sensor 17 rises, and detects the period between these rises using the output of the counter 37. The A/D converter 50 A/D converts the output of the throttle opening sensor 24 and outputs it to the CPU 40 . The timer 38 generates an interrupt signal to the interrupt signal P of the CPU 40 at predetermined intervals. The A/D converter 39 A/D converts the battery voltage 8, and the CP TJ 40 takes in data of this battery voltage at predetermined intervals. The timer 43 is preset by the CPU 40 and the output port P
2 to output a pulse of a predetermined width, and this output drives the injector 14 via the driver 44. Further, the CPU 40 sets the energization angle Tl1w in the timer 46 and sets the ignition timing in the timer 47. As shown in FIG. 9, timers 46 and 47 count the 1° signal output from the crank angle sensor 17, and output a signal to the DF/F 48 when the count reaches zero.

The timer 47 starts counting at the rising edge of the crank angle.
When it becomes zero, a reset signal is sent to the D-F/F 48, and the current to the ignition coil 19 is cut off. The timer 46 starts counting down when the timer 47 reaches zero, and when it reaches zero, D
- Set F/F4B and energize the ignition coil 19.

Next, the operation of the CPU 40 will be explained with reference to FIGS. 3 to 6. Figure 3 shows the main program of the CPU 40,
When a reset signal is input to PL) 40, step 1
In step 101, the output of the water temperature sensor 18 is A/D converted and stored in the RAM 42 as WT. Step 10
2, A/D converts the battery voltage and stores Vn in RAM42.
be memorized as . In step 103, the output of the throttle opening sensor 24 is A/D converted and stored in the RAM 42 as TP. In step 104, 30/TR is calculated from the period TR of the crank angle sensor 7, and the rotational speed N is determined. Calculate. In step 105, the load data AN
From the rotation speed N, calculate A, N-N, /30, and get A
Calculate the output frequency F of FS13. Step 106
Now, the basic driving time conversion coefficient KP is calculated from fl set as shown in FIG. 4 for the output frequency F. In step 107, the conversion coefficient KF is corrected using the water temperature data WT and stored in the RAM 42 as a driving time conversion coefficient. In step 108, the data table f3 stored in advance in the ROM 41 is mapped from the battery voltage data (1), and the wasted time To is calculated and stored in the RAM 42. In step 109, the energization angle T'DW of the ignition coil 19 is calculated at the rotation speed N, and in step 110, T ew=
180 Te1l is calculated, and T' is set in the timer 46 in step 111.

In step 112, it is determined whether the input flag of the AFS 13 is set. If it is set, the process proceeds to step 113; if it is reset, the process proceeds to step 115. In step 113, the input flag of the AFS 13 is set to a reset signal, and in step 114, a time T is set to the input timer of the AFS 13. In step 115, AFS1
It is determined whether or not the input timer 3 is zero, and if it is zero, it is determined in step 116 that A, F S 13 has failed, and a fail flag is set. If the value is not zero, the fail flag of the AFS 13 is set in step 117, and an error is made. After processing steps 116 and 117, the process returns to step 101 again.

Figure 5 shows interrupting human power P3! 1] This shows the interrupt processing for the output signal of the AFS 13. In step 201, AFS1
In step 202, the output Tp of the counter 33 is detected and the counter 33 is cleared. This T is the period between the rises of the gate 32. In step 203, the period Ta is stored in the RAM 42 as the output pulse period T of the AFS 13, and in step 204, the remaining pulse data Po is added to the accumulated pulse data P and l, and the result is set as new accumulated pulse data PR. This integrated pulse data P is the one that integrates the number of pulses of the AFS 13 output during the rise of the crank angle sensor 17, and is
For convenience of processing, one pulse of FS13 is multiplied by 156. In step 205, the remaining pulse data P is set to 156, and in step 206, the CPU 40's P port is inverted, and the interrupt processing is ended.

FIGS. 6(5) and 6(b) show an interrupt process when an interrupt signal is generated in the interrupt P4 of the CPU 40 due to the output of the crank angle sensor 17. In step 301, it is determined whether or not the fail flag of the AFS 13 is set. If it is set, the process proceeds to step 324, and if it is reset, the process proceeds to step 302. In step 302, the period between the rises of the crank angle sensor 17 is read from the counter 37, stored in the RAM 42 as the period TR, and the counter 37 is cleared. In step 303, the period Ti
It is determined whether or not there is an output of the AFS 13 within the period, and if there is, in step 304, the time difference Δ between the time tel of the immediately preceding output pulse of the AFS 13 and the current interrupt time tow of the crank angle sensor 17 is calculated as −toz to+ is calculated and set as the period 'rS. A F S within period T, l]
, 3, the period TR is set to the period T in step 305.

In step 306, the time difference Δt is converted into output pulse data ΔP of A, F S 13 by calculating 156×Ts/Ta. That is, the pulse data ΔP is calculated assuming that the previous output pulse period of the AFS 13 and the current output pulse period of the AFS 13 are the same. Step 307
Then, if the pulse data ΔP is smaller than 156, the process proceeds to step 309, and if it is larger, ΔP is set to 15 in step 308.
Clip to 6. In step 309, the pulse data ΔP is subtracted from the remaining pulse data P, and new remaining pulse data Pn is obtained. In step 310, if the remaining pulse data P, is positive, the process advances to step 313; otherwise, the calculated value of the pulse data ΔP is A F S 1.3
Since it is larger than the output pulse of Δ
P is set to be the same as P, and the remaining pulse data P0 is set to zero in step 312. In step 313, the pulse data ΔP is added to the integrated pulse data PR to obtain new integrated pulse data PR. This PR corresponds to the number of pulses that the AFS 13 is thought to have output during the current rise of the crank angle sensor 17. In step 314, the load data AN calculated up to the previous rise of the crank angle sensor 17 is
From the integrated pulse data P, K1・AN+K z P
Calculate R and use the result as new load data AN
shall be. In step 315, the load data AN is set to a predetermined value α.
If it is larger, it is clipped to α in step 316, so that the load data AN is thicker than the actual value even when the engine 1 is fully open (so that it is not too thick.In step 317, the integrated pulse data P is cleared. Step 31
8, from the load data AN and the drive time conversion coefficient, and the wasted time T, the drive time data T, =AN -K, +T,
is calculated, and in step 319 the drive time data 'rl
is set in the timer 43, and the timer 43 is set in step 320.
By triggering, four injectors 14 are simultaneously driven in accordance with data T1. In step 321, the rotational speed N1 is calculated from the above-mentioned T7, and in step 322, the ignition time A is determined by mapping from A, N, and N to the data table f shown in FIG. 10 stored in the ROM 41 in advance. In step 323, this result is set in the timer 47, and the interrupt processing ends.

On the other hand, if the fail flag of the AFS 13 is set, that is, when the AFS 13 fails, it is determined in step 324 whether the throttle opening data TP is greater than a predetermined value TP, and if it is smaller, the driving time is determined in step 326. Data T, is set to PW, and if it is larger, it is determined in step 325 whether T P is larger than T P 2, which is larger than TP+, and if it is smaller, T is determined in step 328.
, is set in PW2. Also, if it is large, step 3
27, T is set to PW3. In step 329, waste time T is added to this T1, in step 330, this T1 is set in the timer 43, and in step 331, the timer 43 is triggered to drive the injector 14. In step 332, the number of revolutions is N. In step 333, the maximum value A N of the load data AN is calculated, and the 10th
It is determined by mapping the data table fS shown in the figure to the ignition time. At this time, the number of rotations is N. Also performs interpolation calculations. In step 334, the ignition time A is set in the timer 47, and the interrupt processing is ended.

FIG. 7 shows the operation of the input timer of the AFS 13, which counts down until it reaches zero.

FIG. 8 shows the timing when the frequency division flag is cleared in the process of FIG. 3 and FIGS. 17 output is shown. (C1 indicates the remaining pulse data PD, which is set to 156 at each rise and fall of the frequency divider 31 (A, the rise of the output pulse of FS13), and is set to 156 at each rise of the crank angle sensor 17, for example, PB (= Pn 156 X
It is changed to the calculation result of Ts/Ta. fdl indicates a change in the integrated pulse data P, and shows how the remaining pulse data P and l are integrated each time the output of the frequency divider 31 rises or falls.

In the above embodiment, the output pulses of the AFS 13 during the rising edge of the crank angle sensor 17 were counted, but this may also be during the falling edge, or the output pulses of the AFS 13 during several periods of the crank angle sensor 17. You can also click the numbers. Further, although the output pulses of A and FS 13 are counted, the number of output pulses may be multiplied by a constant corresponding to the output frequency of A and FS 13 and then counted. Also, AFS
Although the load data was fixed at the maximum value A N w at the time of No. 13 failure, it may be fixed at an intermediate value.

〔Effect of the invention〕

As described above, according to the present invention, when a failure occurs in the load detection means, a data table in which the ignition timing is determined in advance based on the load and the rotational speed is used to control the ignition timing to correspond to the rotational speed with the load fixed. Since the ignition timing is varied according to the rotation speed, drivability can be improved. Furthermore, there is no need to use a special data table, and there is no need to increase memory capacity.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an ignition timing control device according to the present invention, FIG. 2 is a block diagram showing a specific embodiment of the ignition timing control device for the internal combustion engine, and FIGS. 6 and 7 are flowcharts 1 and 4 showing the operation of the ignition timing control device for an internal combustion engine according to an embodiment of the present invention, and FIG.
A diagram showing the relationship between the basic drive time conversion coefficient and the output frequency. FIG. 8 is a timing chart showing the timing of the flows in FIGS. 3, 5, and 6. FIG. 9 is a timing chart showing the on/off operation of the ignition coil. Chart, Figure 10 is R
This is an ignition timing map stored in the OM. 1... Engine, 12... Throttle valve, 13
... Air flow sensor (Karman vortex flowmeter), 17.
・・Crank angle sensor, 19・・Ignition coil, 20・
... AN detection means, 21 ... control means, 24 ... throttle opening sensor. Note that the same reference numerals in the figures indicate the same or corresponding parts. Agent Masuo Oiwa Figure 5

Claims (1)

[Claims] Failure of the load detection means for detecting the engine load, the rotation speed detection means for detecting the engine rotation speed, the storage means for storing the ignition timing according to the engine load and rotation speed as a data table, and the load detection means. failure detection means for detecting the above data table and the engine speed based on the data table, the load, and the rotational speed; An ignition timing control device comprising a control means for controlling the ignition timing.