JPH044467B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an ignition timing control device for an internal combustion engine.

It is well known that the octane number of gasoline has a strong correlation with knock resistance in internal combustion engines. In other words, the higher the octane number, the more difficult it is to knock. FIG. 1 shows the ignition timing-output shaft torque characteristics of an internal combustion engine using commercially available regular gasoline and premium gasoline (which has a higher octane number than regular gasoline). Point A is the knock limit point when regular gasoline is used, and point B is the knock limit point when premium gasoline is used. Knock occurs when the ignition timing is advanced beyond the knock limit point. According to FIG. 1, when premium gasoline is used, the ignition timing can be advanced to point B, so it is possible to improve the output shaft torque compared to when regular gasoline is used. FIG. 2 is an ignition timing characteristic diagram showing the ignition timing at points A and B in FIG. 1 with respect to the rotational speed of the internal combustion engine.

In an internal combustion engine with such characteristics, when regular gasoline and premium gasoline are mixed or used interchangeably, engine output can be increased by advancing the ignition timing according to the mixing ratio of regular gasoline and premium gasoline. It becomes possible to improve.

[Prior art]

By the way, in conventional ignition timing control devices, the ignition timing characteristics are set only for a predetermined gasoline, for example, regular gasoline.
When using a mixture of premium gasoline or convertible fuel, it was not possible to expect an increase in the engine's output as it was, and the ignition timing had to be reset to the advanced side in some way. In particular, during mixed use, depending on the mixing ratio of regular gasoline and premium gasoline, there is a knock limit point between A and B as shown in Figure 2c, and the possible advance limit changes, so the ignition timing must be reset. It wasn't easy to set up.

[Summary of the invention]

The present invention has been made in view of the above points, and detects the occurrence of a knock using a knock sensor,
Based on the detected value, the ignition timing displacement amount, which indicates the mixture ratio of regular gasoline and premium gasoline in use, is determined, and the ignition timing is set to the advanced or retarded side accordingly.
The purpose is to automatically determine the mixture ratio of regular gasoline and premium gasoline and adjust the ignition timing to the optimal position.

[Embodiment of the Invention] FIG. 8 shows a first embodiment of the invention. 8th
In the figure, reference numeral 1 denotes a knock sensor that is attached to the engine and detects a knock in the engine. Reference numeral 2 designates a knock discriminating unit that determines whether or not a knock has occurred from the output signal of the knock sensor 1, and a band pass filter 2
1, a noise level detector 22, and a comparator 23. The input of the bandpass filter 21 is connected to the knock sensor 1, and the output is connected to one comparison input of the comparator 23 and to the noise level detector 22. The output of the noise level detector 22 is then connected to the other comparison input of the comparator 23. 3
is an ignition timing displacement determination unit that calculates from the output of the knock determination unit 2 and determines the displacement of the ignition timing;
It is composed of an integrator 31, a reset circuit 32, and an adder 33. The input of the integrator 31 is connected to the output of the comparator 23, and the output is connected to one input of the adder 33. Further, the integrator 31 has a reset terminal for resetting the integrated value to zero, and the reset terminal is connected to the output of the reset circuit 32. A storage section 4 stores and holds the output value of the ignition timing displacement determining section 3, and is composed of a peak hold circuit 41 and a reset circuit 42. The input of peak hold circuit 41 is connected to the output of adder 33, and the reset terminal provided in peak hold circuit 41 is connected to reset circuit 42. The output of the peak hold circuit 41 is connected to the other input of the adder 33, and is added to the output value of the integrator 31 by the adder 33. In addition, the peak hold circuit 41
The output of is also connected to a control input of an ignition timing phase shifter 6, which will be explained later. 5 is a reference ignition timing signal generator that generates a reference ignition timing signal for the engine;
Reference numeral 6 denotes an ignition timing phase shifter that controls the phase of the output signal of the reference ignition timing signal generator 5 in accordance with the value of the output of the storage section 4 (output of the peak hold circuit 41).
Reference numeral 7 denotes a switching circuit that energizes the ignition coil 8 on and off in synchronization with the output signal of the ignition timing phase shifter 6 to generate a high voltage necessary for igniting the internal combustion engine. The output of the ignition timing phase shifter 6 is also connected to a reset circuit 32.

Next, the operation of each part will be explained. FIG. 4 shows the operation of each part of the knock discriminating section 2. As shown in FIG. The knock sensor 1 is a generally well-known vibration acceleration sensor,
It is attached to the cylinder block of an engine, converts the mechanical vibration of the engine into an electrical signal, and outputs a vibration wave signal as shown in FIG. 4a. The bandpass filter 21 passes only the frequency component peculiar to the knock from the output signal of the knock sensor 1, suppresses noise components other than the knock, and outputs a signal with a good S/N ratio as shown in A of Fig. 4b. . The noise level detector 22 can be composed of, for example, a half-wave rectifier circuit, an averaging circuit, an amplifier circuit, etc., and converts the output signal of the bandpass filter 21 (a in FIG. 4b) into a direct current by half-wave rectifying and averaging. It is converted to a voltage level and further amplified at a predetermined amplification degree, and as shown in Figure 4b, B, the output signal of the band pass filter 21 (Figure 4B, A) is higher than the noise component and lower than the knock component. outputs a low level DC voltage. Comparator 2
3 compares the output signal of the band pass filter 21 (A in FIG. 4B) and the output signal of the noise level detector 22 (B in FIG. 4B), and if no knock occurs (FIG. 4C section). ) has bandpass filter 2.
1 (a in Figure 4b) does not exceed the output signal of the noise level detector 22 (b in Figure 4b), nothing is output.On the other hand, if a knock occurs (Fig. 4b) In part D), the output signal of the bandpass filter 21 (a in Fig. 4b) is sent to the noise level detector 2.
In order to exceed the output signal No. 2 (b in FIG. 4), a pulse train is output as shown in FIG. 4c. Therefore, the occurrence of a knock can be determined by the presence or absence of a pulse train (FIG. 4c) from the output of the comparator 23.

FIG. 5 shows the operation of each part of the ignition timing displacement determining section 3, the storage section 4, and the ignition timing phase shifter 6. The integrator 31 integrates the pulse train (FIG. 5c) output from the comparator 23. On the other hand, the reset circuit 32 receives the output signal (ignition signal) of the ignition timing phase shifter 6, outputs a pulse as shown in FIG. Reset to . Therefore, the output of the integrator 31 has a waveform as shown in FIG. 5d, in which the output voltage increases when a knock occurs and is reset at each ignition timing.

Next, the adder 33 uses the output value of the integrator 31 (FIG. 5d) and the peak hold circuit 41 (described later).
and the output value of However, the output value of the peak hold circuit 41 that is added is the value before addition,
This value is held inside the adder 33 while the value of the integrator 31 is being input. A peak hold circuit 41 holds the peak value of the output of the adder 33. FIG. 5f shows the peak hold circuit 41
The output waveform of is shown. The reset circuit 42 outputs a high level pulse when starting the engine.
FIG. 5g shows the output pulses of the reset circuit 42. First, when starting the engine, the peak hold circuit 4
1 is reset by the reset circuit 42, and the output becomes zero level. When a knock occurs in the engine and a pulse train appears in the output of the comparator 23 as shown in FIG. 5c, the integrator 31 integrates the pulse train (FIG. 5d), and the adder 33 The integrated output value and the output value of the peak hold circuit 41 before addition are added, and the peak hold circuit 41 holds the peak value of the output of the adder 33 (FIG. 5f).
The above operation continues until no knocks occur in the engine, and the output value of the peak hold circuit 41 increases.

On the other hand, the ignition timing phase shifter 6 controls the phase of the input signal to be retarded in accordance with the control voltage. This ignition timing phase shifter 6 is a well-known technique in ignition timing control devices, and its explanation will be omitted here. The reference ignition timing signal generator 5 detects the rotation of the crankshaft of the engine and outputs a signal indicating when to ignite, and is, for example, an ignition signal generator built in a distributor. The ignition timing characteristics of the reference ignition timing signal generator 5 are set depending on the engine speed and load, and regarding the engine speed, the characteristics are set as shown in FIG. 2B. The output signal of the reference ignition timing signal generator 5 is shown as shown in FIG. 5h, and is input to the ignition timing phase shifter 6. Then, the output of the peak hold circuit 41 is input to the control voltage input of the ignition timing phase shifter 6, and the output signal of the reference ignition timing signal generator 5 is retarded in accordance with the output value of the peak hold circuit 41. . The output signal of the ignition timing phase shifter 6 is shown in FIG. 5i. Now, when the output of the peak hold circuit 41 is at zero level, the ignition timing phase shifter 6 does not perform a phase shifting operation, and the output signal of the reference ignition timing signal generator 5 appears as it is at its output, so that the actual The ignition timing characteristics for ignition remain as shown in FIG. 2B. Further, when a knock occurs in the engine, the ignition timing displacement determining section 3 calculates the retard phase shift amount, and the output value of the peak hold circuit 41 increases, the ignition timing phase shifter 6 changes to the state shown in FIG. As shown, the output signal (h in FIG. 5) of the reference ignition timing signal generator 5 is retarded in phase in accordance with the output value of the peak hold circuit 41. Therefore, the ignition timing characteristic in actual ignition is as shown by the broken line shown in section 2c.

Therefore, when using premium gasoline,
In the ignition timing characteristics shown in Fig. 2B, no knock occurs, so the ignition timing does not retard, and the second
If the characteristics shown in Figure B remain the same, and if regular gasoline or a mixture of regular and premium gasoline is used, the ignition timing characteristics shown in Figure 2 B are in the region where knocks occur, so the engine A knock occurs. As described above, the knock discrimination section 2, the ignition timing displacement amount determination section 3,
The amount of knock occurrence is detected by the storage unit 4 and the ignition timing phase shifter 6, and the ignition timing is retarded according to the amount of knock occurrence, so when regular gasoline or a mixture of regular and premium gasoline is used. Also, the ignition timing is fixed to the ignition timing characteristic that does not cause knocking (Fig. 2A when regular gasoline is used, and Fig. 2C when regular and premium mixed gasoline is used). Therefore, the amount of nozzles generated is correlated with the octane number of the gasoline used, and also with the mixing ratio of regular gasoline and premium gasoline.

In the above embodiment, the ignition timing displacement amount determining section 3 and the storage section 4 are configured with analog circuits, but when the ignition timing phase shifter 6 is configured with a digital circuit, the following sections are configured with digital circuits. Similar operations and effects can be obtained even if the configuration is configured as follows. The integrator 31 may be replaced with a counter, the adder 33 with a digital adder, and the peak hold circuit 41 with a digital memory.

Next, a second embodiment of the present invention will be described. This embodiment differs from the first embodiment in the configuration and operation of the ignition timing displacement determining section 3 and storage section 4. FIG. 6 shows the configuration of this embodiment. However, the storage section 4 is included in the ignition timing displacement determining section 3. In FIG. 6, 34 is a pulse generator, 35
36 is a timer, 37 is an integrator, and 38 is a reset circuit. The input of the pulse generator 34 is connected to the output of the comparator 23, and the output is connected to the counter 35.
connected to the counting input of Also, timer 36 is connected to the reset input of counter 35. Integrator 3
7 integrates the output of the counter 35, and its output is connected to the ignition timing phase shifter 6. Further, the other configurations are similar to those of the embodiment described above, and the same reference numerals as in FIG. 3 indicate the same parts.

FIG. 7 shows the operation of each part of the ignition timing displacement determination section 3. The pulse generator 34 outputs pulses as shown in FIG. 7j in response to the pulse train outputted by the comparator 23 (FIG. 7c). That is, the pulse generator 34
outputs one pulse for each knock occurrence for one ignition. The output pulses of the pulse generator 34 are counted by a counter 35, and the contents of the count are shown in FIG. 7k. The timer 36 outputs a pulse at predetermined time intervals as shown in FIG. 7l, and the pulse resets the count value of the counter 35 to zero. Further, the output of the counter 35 becomes high level when the count value of the counter 35 exceeds a predetermined value (count value 3 in FIG. 5) as shown in FIG. 7m. That is, when a predetermined number of knocks occur within a predetermined time, the counter 35 outputs a high level signal. This is to calculate the knock occurrence rate. Then, the integrator 37 integrates the output of the counter 35 (m in FIG. 7) and stores and holds the integrated value as shown in n in FIG. 7. Similar to the reset circuit 42 in the first embodiment, the reset circuit 38 outputs a pulse when the engine is started, and resets the integrated value of the integrator 37 to zero level. On the other hand, the ignition timing phase shifter 6 retards the reference ignition timing signal according to the output level of the integrator 37.

Therefore, according to this embodiment, by calculating the knock occurrence rate of the engine and integrating the results, the ignition timing characteristics are fixed as shown in Fig. 2c when using regular gasoline or a mixture of regular and premium gasoline. can do.

In the above embodiment, the knock occurrence rate is calculated and the ignition timing is retarded, but the output pulse of the comparator 23 may be directly input to the integrator 37 for simplicity.

Regarding the reset circuit 42 and the reset circuit 38 in the above two embodiments, the method of generating a pulse when starting the engine has been shown, but it is also possible to It is also possible to detect that new gasoline has been injected by detecting a change in the gasoline remaining gauge and output a reset pulse.

Incidentally, in the first and second embodiments described above, the reference ignition signal is retarded in phase according to the output of the storage section 4, but the two reference ignition timing signals having different ignition timing characteristics are The ignition timing may be changed depending on the output of the storage section 4 between the two. This is the third
An example will be described below.

FIG. 8 shows a block diagram of an eighth embodiment of the present invention. In FIG. 8, the same reference numerals as in FIG. 8 indicate the same parts. Reference numeral 9 denotes a proportional coefficient calculator, which converts the signal level output from the storage section 4 into a proportional coefficient. 10 is a first ignition timing characteristic storage unit (hereinafter referred to as
ROM10) and 11 are second ignition timing storage units (hereinafter referred to as ROM11), and as shown in Fig. 9, ignition timing data is stored in memory addresses determined by the engine speed and load. remembered. 12 is an interpolation calculator;
Input the data of ROM10 and ROM11 and the output value of the proportional coefficient calculator 9, and input the data of ROM10 and ROM11.
An interpolation operation is performed between the data using the coefficients output from the proportional coefficient calculator 9, and the result of the operation is output.
13 is a crank angle sensor that detects the crank rotation angle of the engine, and 14 is a pressure sensor that detects the intake air pressure of the engine. 15 is an ignition timing calculator which calculates the engine speed from the output signal of the crank angle sensor 13, detects the load state of the engine from the pressure sensor 14, and calculates a value determined based on the engine speed and load. is converted into an address value, and the address value is output to ROM10 and ROM11. Also, the ignition timing calculator 15 is the interpolator 1
Read the output data of 2, crank angle sensor 1
The ignition timing is calculated from the output data of the interpolation calculator 12 using the output signal of 3 as a reference, and the ignition signal is output to the switching circuit 7.

Next, the calculation methods of the proportional coefficient calculator 9 and the interpolation calculator 12 will be explained. Now, when the proportional coefficient calculator 9 receives the signal level of V _R from the storage section 4, it divides this V _R by the preset maximum output level V _Rnax from the storage section 4, and calculates the division result. is the proportional coefficient k (=V _R /V _RMAX ). Therefore, as can be seen from the first and second embodiments described above, when premium gasoline is used, k=0, when regular gasoline is used, k=1, and when premium and regular gasoline is used, 0<k<1. Become. Therefore, it can be seen that k is a coefficient indicating the mixing ratio of premium gasoline and regular gasoline.

On the other hand, the ROM 10 and ROM 11 receive address values corresponding to the engine speed and load from the ignition timing calculator 15, and output the ignition timing data stored at the addresses to the interpolation calculator 12. Now, set the ignition timing characteristics of ROM10 for premium gasoline, set the ignition timing data at the above address to θ _B , set the ignition timing characteristics of ROM11 for regular gasoline, and set the ignition timing data at the above address to θ B. If _A , ROM1
Since the ignition timing characteristic of 0 is set to be the same as that of the ROM 11 or to the advanced side, θ _A ≦ θ _B. Therefore, the interpolation calculator 12 calculates θ _B - (θ _B - _{θ A} )·k, and if the result is θ _C , θ _C is the distance between θ _B and θ _A , k: (1-k ) is the value internally divided into Therefore, since k=0 when premium gasoline is used, θ _C =
When using regular gasoline, k = 1, so θ _C = θ _A. When using premium and regular gasoline, 0 < k _< 1, so θ _A <
θ _C < θ _B.

Therefore, θ _C is θ _A and θ _B based on the coefficient k that indicates the blending ratio of premium gasoline and regular gasoline.
Therefore, even when premium gasoline and regular gasoline are mixed, by performing the above interpolation calculation, it is possible to obtain the optimal ignition timing according to the mixing ratio of premium gasoline and regular gasoline. I can do it.

〔Effect of the invention〕

As explained above, according to the present invention, when regular gasoline and premium gasoline are mixed and used, the knock sensor detects the occurrence of a knock, and based on this, the displacement amount of the reference ignition timing is calculated, thereby regulating the knock. This has the effect of automatically adjusting the standard ignition timing characteristics to the optimum ignition timing without knocking in a mixed gasoline of Yura gasoline and premium gasoline. In addition, the amount of knock occurrence or the knock occurrence rate is detected based on the knock occurrence, and the octane number is determined based on the knock occurrence amount or knock occurrence rate to determine the amount of displacement of the ignition timing. It is possible to accurately determine the amount of time displacement. moreover,
The amount of displacement in the ignition timing is temporarily stored, and the ignition timing is changed based on this memorized value.
Stable ignition timing control can be performed.

[Brief explanation of drawings]

1 is an output shaft torque characteristic diagram of the engine, FIG. 2 is an ignition timing characteristic diagram of the engine, FIG. 3 is a block configuration diagram showing the first embodiment of the present invention, and FIG. An explanatory diagram of the operation, FIG. 5 is an explanatory diagram of the operation of the ignition timing variation determining section 3, the storage section 4, and the ignition timing phase shifter 6. FIG. 6 is a block diagram showing the second embodiment of the present invention. FIG. 7 is an explanatory diagram of the operation of the ignition timing variation determination unit 3 of the second embodiment, FIG. 8 is a block diagram showing the third embodiment of the present invention, and FIG.
FIG. 3 is an ignition timing characteristic diagram in an embodiment of the present invention. 1 is a knock sensor, 2 is a knock discrimination section, 3 is an ignition timing displacement determining section, 4 is a storage section, 5 is a reference ignition timing signal generator, 6 is an ignition timing phase shifter, 7 is a switching circuit, and 8 is an ignition coil. It is. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A knock sensor that detects a knock in an internal combustion engine;
Knock determination means determines whether or not a knock has occurred from the output of the knock sensor, and the amount or rate of knock occurrence is calculated from the output of the knock determination means, and the octane value of the fuel used is determined based on the amount or rate of knock occurrence. displacement determining means for determining the amount of displacement of the standard ignition timing of the engine by determining the amount of displacement of the standard ignition timing of the engine; storage means for storing the maximum value of the output of this displacement amount determining means; An ignition timing control device for an internal combustion engine, comprising an ignition timing displacement means for displacing the ignition timing. 2. The ignition timing control device for an internal combustion engine according to claim 1, wherein the ignition timing shifting means shifts the reference ignition timing signal in accordance with the output of the storage means. 3. Ignition of an internal combustion engine according to claim 1, wherein the ignition timing shifting means displaces the ignition timing between two reference ignition timing signals having different ignition timing characteristics according to the output of the storage means. Timing control device. 4. Claim 1, wherein the storage means is provided with a reset circuit that initializes the stored contents to a predetermined value when refueling or starting the engine, etc.
An ignition timing control device for an internal combustion engine as described in 2.