JPH03260374A - Ignition timing control device of internal combustion engine - Google Patents

Abstract

PURPOSE:To improve responsiveness relating to a rotation fluctuation by change- setting correction timing advance, determined in accordance with an operation condition for correcting the basic ignition timing advance at idle time, to a large value when heavy fuel is used as compared with non-heavy fuel being used. CONSTITUTION:An idle condition detecting means 11 and an engine speed detecting means 12 are provided, and the basic ignition timing advance at idle time is corrected by correction ignition timing advance in accordance with an engine speed deviation to calculate ignition timing so that the actual engine speed obtains a target engine speed when an internal combustion engine 10 is detected in an idle condition by an ignition timing calculating means 13 to which detection signals of these means 11, 12 are input. An ignition means 14 is ignition-operated by timing in accordance with this ignition timing. Here a fuel quality detecting means 17, which detects difficulty to vaporize of fuel in a fuel tank 15, is provided. The correction timing advance is change-set to a large value by a correction timing advance variable means 18 when heavy fuel is used as compared with non-heavy fuel being used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ignition timing calculation means for internal combustion engine open, and in particular, for the purpose of idle stabilization, it is possible to calculate the engine speed and target engine speed when the internal combustion engine is in the idle state. Adjust the ignition timing according to the deviation from the number! This invention relates to an ignition timing control device.

[Conventional technology]

The engine speed when the internal combustion engine is in the idle state is set at a low speed from the viewpoint of improving fuel efficiency and reducing vibration. , the amount of unburned components in the exhaust gas increases, the engine speed becomes unstable, and in extreme cases, engine stalling occurs.

Therefore, in order to stabilize the engine speed when an internal combustion engine is idling (hereinafter referred to as idling speed), it has been conventionally done so that the engine speed becomes the target speed (for example, the average value of the idling speed). Basic ignition advance angle θ at idle
8A3. It has been proposed to correct the ignition advance angle θid according to the difference between the engine rotation speed and the m rotation speed (
[Problems to be Solved by the Invention] However, in the above-mentioned conventional 5A position, the corrected ignition advance angle θi
When calculating dl, 1! used for internal combustion engines! ! Since the distillation characteristics (fuel properties) of the fuel are not taken into consideration, the followability of the correction may not be sufficient depending on the fuel properties of the fuel used, resulting in deterioration of the stability of the idle speed.

That is, to explain this in more detail, for example, based on whether or not 50% or more of the fuel evaporates at 100°C, in addition to normal fuel, 50%
Light fuel with a lot of low-boiling seafood that evaporates more than 50%
There are heavy fuels with a lot of high-boiling seafood that evaporates.

Therefore, the amount of fuel that flows in liquid form and adheres to the walls of the intake pipe without evaporating is greater in heavy fuel than in light fuel.
For this reason, the amount of liquid fuel adhering to the inner wall surface of the intake boat is larger for heavy fuel, which has a larger amount of fuel that flows in liquid form, than for light fuel.

On the other hand, the fuel from the fuel injection valve and a portion of the fuel adhering to the inner wall of the intake boat enter the combustion chamber of the engine, but the amount of fuel supplied to the combustion chamber is determined from these amounts of fuel This value is obtained by subtracting the amount of fuel that adheres to the inner wall of the boat.

However, the amount of fuel adhering to the inner wall surface of the intake boat is unstable, and as mentioned above, the amount of heavy fuel is larger. The amount does not remain constant and varies from cycle to cycle, resulting in large cycle-to-cycle fluctuations in the air-fuel ratio. Therefore, even if the corrected ignition advance angle θidl is suitable for correcting fluctuations in idle speed when using non-heavy fuel such as light fuel or regular fuel, the followability of the correction is insufficient when using heavy fuel, and the idle This leads to deterioration of stability. On the other hand, the corrected ignition advance angle θidl suitable when using heavy fuel
If it is set to , the correction width becomes excessive when non-heavy fuel is used, and the overcorrection also deteriorates the idle stability.

The present invention has been made in view of the above points, and by setting the corrected ignition advance angle to a larger value when using heavy fuel than when using non-heavy fuel, it is possible to stabilize the idle when using heavy fuel. Ignition timing of internal combustion engine that can improve performance 1iIJIll
The purpose is to provide equipment.

[Means to solve the problem]

FIG. 1 shows a basic configuration diagram of the present invention. In the same figure, 10 is internal combustion! Il[1, 11 are idle state detection means.

12 is a rotation speed detection means, and 13 is an ignition timing calculation means.

Reference numeral 14 denotes an ignition means, and in the present invention, the ignition timing calculation means 13 calculates the basic ignition advance angle during idling by adjusting the rotation speed so that the rotation speed detected by the rotation speed detection means 12 becomes the target rotation speed during the idling state. The ignition FR period is calculated by correcting the ignition advance angle according to the deviation between the target rotation speed and the target rotation speed, and the ignition means 1
In the ignition timing control device that controls the ignition of the internal combustion engine 10 at a timing according to the ignition timing calculated by 4, a fuel property detection means 17 detects the difficulty of evaporation of the fuel 16 in the fuel tank 15; It is equipped with a corrected ignition advance angle variable means 18 that changes and sets the corrected ignition advance angle to a larger value when heavy fuel is used than when non-heavy fuel is used.

[Effect]

When using heavy fuel, the air-fuel ratio fluctuates more from cycle to cycle than when using non-heavy fuel, and the idle speed is quite unstable. Therefore, in the present invention, when heavy fuel is used, the corrected ignition advance angle is changed and set to a larger value by the corrected ignition advance angle variable means 18 than when non-heavy fuel is used, so that the stabilizing advance angle is set to a larger value.

The amount of retardation is increased, and responsiveness to rotational fluctuations can be improved. Furthermore, since the corrected ignition advance angle is set to a small value when using real heavy fuel, over-correction can be prevented.

〔Example〕

FIG. 2 shows the S factor in one embodiment of the present invention. In the figure, the same components as in FIG. 1 are given the same reference numerals. This embodiment is an example in which four cylinders are used as the inner*m engine 10, and the microcomputer 21, which will be described later, is used. IIm is done.

In FIG. 2, a surge tank 24 is provided downstream of the air cleaner 22 via a throttle valve 23. An intake temperature sensor 25 is installed near the air cleaner 22 to detect the intake air temperature, and the throttle valve 2
3 is attached with an idle switch 26 that is turned on when the throttle valve 23 is fully closed. This idle switch 26 constitutes the idle state detection means 11. Further, a diaphragm type pressure sensor 27 is attached to the surge tank 24.

Further, a bypass passage 28 is provided which bypasses the throttle valve 23 and communicates the upstream side and the downstream side of the throttle valve 23, and an idler valve whose opening degree is controlled by a solenoid is provided in the middle of the bypass passage 28. A speed control valve (JSCV) 29 is installed. The duty ratio of the current flowing through this l5CV29 is controlled to adjust the valve opening degree to ll11! II. By adjusting the amount of air flowing into the bypass passage 28,
The idle link rotation speed is controlled to the target rotation speed.

The surge tank 24 is communicated with a combustion chamber 33 of an engine 32 (corresponding to the internal combustion engine 10) via an intake manifold 30 and an intake boat 31. A 1 m fuel valve 52 is disposed for each cylinder so that a portion thereof protrudes into the intake manifold 30, and this fuel II valve 52
Fuel 16 into the airflow through the intake manifold 30 at
is injected.

The combustion chamber 33 is connected to the catalyst V! via an exhaust boat 34 and an exhaust manifold 35. It is connected to c1136.

Moreover, 37 is an ignition plug, which is provided so that a part thereof protrudes into the combustion chamber 33. Further, 38 is a piston that reciprocates in the vertical direction in the figure.

The igniter 39 generates a high voltage, and a distributor 40 distributes and supplies this high voltage to the spark plugs 37 of each cylinder. Igniter 39. The distributor 40 and the spark plug 37 constitute the ignition means 14.

The rotation angle sensor 41 detects the rotation of the shaft of the distributor 40 and outputs an engine rotation signal to the microcomputer 21, for example, every 30' CA. That is, the rotation angle sensor 41 constitutes the rotation speed detection means 12 described above.

A water temperature sensor 42 is provided so as to penetrate through the engine block 43 and partially protrude into the water jacket, and detects the temperature of engine cooling water and outputs a water temperature sensor signal. Furthermore, a part of the Ili elementary concentration detection sensor (02 sensor) 53 is connected to the 1
The oxygen concentration in the exhaust gas before entering the catalyst device 36 is detected.

Further, a fuel temperature sensor 44 is provided at the bottom of the fuel tank 15, and the temperature of the fuel 16 is measured by this. A vapor passage 45 is provided in the upper part of the fuel tank 15, and the vapor passage 45 communicates with a canister 47 via a vapor flow meter 46.

The vapor generated in the fuel tank 15 flows into the canister 47 after its flow rate is measured by a vapor flow meter 46 . This vapor flow meter 46 is equipped with a rotating section 48 that responds to the flow rate of vapor, and a signal rotor (not shown) is attached to the rotating section 48.

Further, 49 is a vapor flow rate sensor, which is installed in the housing part of the vapor flow meter 46, and when the jig-pull rotor of the rotating part 48 crosses the vapor flow point +j49, it becomes a high voltage, and when it moves away, it becomes a low voltage (i.e. , rotating part 4
8) generates a vapor flow rate detection signal and sends it to the microcomputer 21. The vapor flow source sensor 49 and the microcomputer 21 constitute the fuel property detection means 17 described above.

On the other hand, the vapor adsorbed in the canister 47 is sucked into the intake manifold 30 via the purge passage 50. Since the purge passage 50 is provided with an orifice (not shown), the negative pressure of the intake manifold 30 is not directly applied to the fuel tank 15. This purge passage 5
The opening degree of the purge control valve 51 provided in the middle of the purge passage 50 is adjusted by adjusting the current flowing from the microcomputer 21 to the renoid, and the purge flow rate flowing through the purge passage 50 is adjusted.

The microcomputer 21 which controls the operation of each part of this embodiment having such a configuration has a hardware configuration as shown in FIG. In the figure, the same components as those in FIG. 2 are denoted by the same reference numerals, and the explanation thereof will be omitted. In FIG. 3, the microcomputer 21 includes a central processing bag M (CPU
)60. Read-only memory (ROM > 61) that stores processing programs. Random access memory (RAM) used as a work area 62. Backup RAM that retains data even after the engine is stopped 63°CPU 6
Clock generator 6 that supplies its master clock to 0
4, which are connected to each other via a bidirectional path line 65, and are also connected to the output port lower 6, the input port lower, and the output ports 8 to 71, respectively.

The microcomputer 21 also receives a pressure detection signal from the pressure sensor 27 taken out through a filter 73 and a buffer 74 in series, an intake temperature detection signal from the intake temperature sensor 25 taken out through a buffer 75, and a buffer 74.
The water temperature sensor signal (chome W) from the water temperature sensor 42 taken out through the buffer 77, the fuel temperature detection signal from the fuel temperature sensor 44 taken out through the buffer 77, and the back 780
The oxygen concentration detection signal from the 02 sensor 53 is supplied to the multiplexer 78 via the oxygen concentration detection signal from the 02 sensor 53. Note that the filter 73 described above is a filter for removing the pulsating component of the intake pipe pressure contained in the output detection signal of the pressure sensor 27.

As a result, each input detection signal of the multiplexer 78 is
The signals are sequentially selected and outputted from the multiplexer 78 under the control of the PLJ 60, converted into digital signals by the A/D converter 79, and stored in the R to M62 via the path line 65.

Further, the microcomputer 21 inputs signals obtained by waveform shaping each detection signal from the rotation angle sensor 41 and the vapor flow rate sensor 49 by a waveform shaping circuit 82, and the output signal of the idle switch 26 after passing through a buffer (not shown). Supply to Poudloa.

Furthermore, the microcomputer 21 has drive circuits 83 to 86.
The signal from the output port 8 is sent to the drive circuit 8.
3 to the igniter 39, a signal from the output port door 9 is supplied to the fuel injection valve 52 via a drive circuit 84 equipped with a down counter, and a signal from the output port door 0 is sent to the fuel injection valve 52 via a drive circuit 85. The output signal from the output port door 1 is supplied to the purge control valve 51 via the drive circuit 86.

The microcomputer 21 having such a hardware configuration realizes the above-described ignition timing calculation means 13 and corrected ignition advance angle variable means 18 through software processing operations.

Next, to explain the processing operation by the microcomputer 21, first, the fuel property detection operation will be explained with reference to FIG. 4.

FIG. 4 shows a calculation routine for detecting fuel properties, which is part of the main routine. In the figure, step 9
1, the flow rate measurement time CvΔ is counted up in a 4+ms routine (not shown), and it is determined whether it has exceeded a predetermined value (here, 10 seconds), and if it is within 10 seconds, this routine ends. , when 10 seconds have passed, the flow rate measurement time CVA is reset to zero in the next step 92. Therefore, steps 92 to 96 are executed once every 10 seconds.

On the other hand, the microcomputer 21 operates only when the output detection signal of the vapor flow rate sensor 49 changes from a low voltage to a high voltage (that is, every time the rotating section 48 rotates once).
It has a vapor flow rate counter (not shown) that is counted up by the external interrupt routine that is activated, and after the count value NVA is set to the variable NVAIO in step 93 following step 92, the process is performed in the next step 94. is reset to zero. Therefore, the value of variable NVAIO is
It shows the number of rotations of the rotating part 48 of the vapor flow meter 46 per 10 seconds, and shows a value proportional to the vapor flow rate.

Next, in step 95, a fuel temperature correction coefficient KVA is calculated based on the fuel temperature detection signal 1-IF obtained by detecting the temperature of the fuel 16 by the fuel temperature sensor 44. That is, even if the fuels have the same distillation characteristics, when the fuel temperature is low, the amount of vapor generated is smaller than when the fuel temperature is high. Therefore, in order to correct the difference in vapor generation amount due to fuel temperature, the value of the fuel temperature correction coefficient KVA is set to become larger as the tm temperature becomes lower.

Next, the microcomputer 21 performs the NVA in step 96.
After calculating the fuel vapor amount NVA10-T per unit time by calculating the arithmetic expression 10*KVA, in step 97, the fuel property coefficient K is calculated based on the value NVA10T.
After calculating F, it is stored in the RAM 62. This fuel property coefficient KF is calculated by calculating the vapor flow rate for 10 seconds by the fuel temperature correction coefficient KV.
This is the value corrected by A, and as shown in Figure 5, when the fuel property coefficient KF is larger than K F 2, it is a light fuel with less high boiling point content, and when KF is smaller than KFI, it is a heavy fuel with a lot of high boiling point content. It can be seen that it is a high quality fuel. In addition, the fuel property coefficient KF includes KFo during normal operation KF2 >KF>K
When the value is within the FI range, it can be considered that the fuel is neither light nor heavy.

In this example, since the unit time of the vapor flow rate is set to 10 seconds, changes in the tN properties during running can also be seen.

Next, processing operations for implementing the corrected ignition advance angle variable means 18 by the microcomputer 21 will be explained with reference to FIGS. 5 and 6. FIG. 6 is a flowchart showing a correction constant calculation routine, in which, as described later, a correction constant K that determines the corrected ignition advance angle θidl is set to a value corresponding to the fuel properties. In FIG. 6, first, CP[J60 reads the fuel property coefficient KF calculated in the fuel property detection routine shown in FIG. 4 from the RAM 62 in step 101.

Subsequently, in step 102, it is determined whether or not the fuel 16 used is heavy fuel. The determination in step 102 is a comparison of whether the fuel property coefficient KF is less than or equal to a predetermined value KF+ smaller than KFo shown in FIG. 5, and KF≦
When KF+, it is determined that the fuel is heavy, and KF>KFI
When , it is determined that the fuel is not heavy fuel. If it is determined that the fuel is heavy fuel, the process proceeds to step 103 and the correction constant K is set to the maximum value of 1.

When it is determined in step 102 that the fuel is not heavy fuel,
Proceeding to step 104, it is determined whether or not the fuel 16 used is light fuel. This determination is made when the fuel property coefficient KF is the fifth.
This is a size comparison to determine whether the fuel is greater than or equal to a predetermined value KF2 which is larger than KF o shown in the figure. When KF≧KF2, it is determined that the fuel is light, and when KF<KF2, it is determined that it is not light fuel. judge.

If it is determined that the fuel is light fuel, the process proceeds to step 105, where the correction constant K is set to the minimum value of 3.

On the other hand, when it is determined in step 104 that the fuel is not a light fuel, the fuel 16 used has a fuel property coefficient KF of KFI <K
This is the case of normal fuel that is neither light nor heavy, where F<KF2, and in this case, proceed to step 106 and set the correction constant K.
2 to a value intermediate between 1 and 3 (i.e., Kl >
K2 > K3).

Step 103. After processing 105 or 106, this subroutine is ended (step 107).

Next, processing operations for realizing the ignition timing calculation means 13 by the microcomputer 21 are shown in FIGS.
This will be explained with reference to Figure 0. Microcomputer 21 is the seventh
After calculating the corrected ignition advance angle θidl using the routine shown in the figure,
Calculate the ignition timing θ using the calculation routine for ignition shown in Figure 9,
The igniter 39 described above is turned on.

The corrected ignition advance angle calculation routine shown in FIG. 7 is started at every predetermined crank angle (for example, 120° CA) and uses the rotational speed signal NE obtained by the rotational angle sensor 41.

The value of the detection signal @LL of the idle switch 26 is read from the RAM 62 described above in step 201, respectively. Next, the process proceeds to step 202, where a weighted average value NEAV of the rotational speed is calculated as the target rotational speed.

This NEAV is calculated based on the following equation, for example.

In other words, the weighted average value NEAV is 3 of the previous weighted average value.
It is obtained by dividing the value obtained by adding the current rotational speed NE to the 1-times value by 32.

Next, in step 2 (based on the above-mentioned belief in step 13), whether it is idle (L = "1") or not in idle state (LL
-“O”). When it is determined that the engine is in the idle state, the process proceeds to step 204, where the idle rotation speed NF is subtracted from the weighted average value NEAV, which is the target rotation speed, to calculate the rotation speed deviation ΔNE.

On the other hand, when it is determined in step 203 that the engine is not in an idle state (in an off-idle state), the process proceeds to step 205, where the current rotational speed NE in an off-idle state is set to a weighted average value NEAV, and then in step 204, NEAVNE is calculated. Therefore, when the engine is not in an idle state, the rotational speed deviation ΔNE is zero.

When the calculation of the rotation speed deviation △NE is completed in step 204, the process proceeds to step 206, moves to the subroutine marked with # in FIG. 6, calculates the correction constant, and then goes to step 20γ in FIG. After calculating the corrected ignition advance angle θidl based on the formula ΔNE and storing it in the RAM 62, this routine ends (step 208).

As mentioned above, the correction constant has a value that depends on the fuel properties, and is set to a larger value when using heavy fuel than when using non-heavy fuel. The corrected ignition advance angle θidl at idle obtained by multiplying by ΔNE becomes maximum when heavy fuel is used when ΔNE is the same. That is, the relationship between the corrected ignition advance angle θidl and the rotational speed deviation ΔNE during idling is as shown in FIG. Note that since ΔNE is zero when the engine is not in an idling state, the value of the corrected ignition advance angle θidl is always zero regardless of the fuel properties.

Using the thus calculated corrected ignition advance angle θidl, the ficrocomputer 21 calculates the ignition timing θ, which is the corrected basic ignition advance angle θBASE during idling, according to the routine shown in FIG. In FIG. 9, step 301
It is determined from the detection signal LL of the idle switch 26 whether or not it is in the idle state (Ll="1"), and when it is determined that it is in the idle state, the process proceeds to step 302, and a one-dimensional map as shown in FIG. 10 is referred to. Then, the basic ignition advance angle θBASE is determined from the idle speed NE at that time.

Subsequently, the CPU 60 stores the corrected ignition advance angle θ1,1 calculated in the routine shown in FIG. 7 from the RAM 62 in step 30.
3, and in the next step 304, the corrected ignition advance angle θ1,1 is added to the basic ignition advance angle θ8A8° to calculate the ignition timing θ at idle, and then this routine ends (step 306).

Note that when it is determined in step 301 that the idle is off, the process proceeds to step 305 and the ignition timing θ is adjusted according to the operating state.
After the calculation is performed and the corrected ignition advance angle θidl is set to zero, this routine ends (step 306).

The above-mentioned igniter 39 turns on the primary current of the ignition coil from a certain crank angle before the calculated ignition timing θ under the control of the ficrocomputer 21, and turns off the above-mentioned -next N current at the timing of the ignition timing θ. As a result, a high voltage is generated and the spark plug 37 is ignited.

As described above, when the engine speed NE is lower than the target speed NEAV during idling, the ignition timing θ is advanced in accordance with the difference ΔNE, thereby stabilizing the idling speed. For example, when using heavy fuel, the corrected ignition advance angle θidl is set larger than when using non-heavy fuel, so the engine operates to match the idle speed with the target speed by a certain amount of correction. It is possible to stabilize the idle speed even when using heavy fuel, which has large fluctuations in the idle speed.

On the other hand, when using non-heavy fuel, the corrected ignition advance angle θidl is set smaller than when using heavy fuel, so when using non-heavy fuel, the idle speed is relatively stable. It can prevent sexual deterioration.

It should be noted that the present invention is not limited to the above-mentioned example; for example, the fuel property detection means 17 may be a means for detecting a change in combustion state based on a difference in response speed to a change in operation (Japanese Patent Laid-Open No. 63-66436). , means for detecting the properties of the fuel used based on the temperature difference before and after mixing the intake air and fuel (
Japanese Utility Model Application No. 62-59740, Japanese Utility Model Application No. 62-59142), Means for detecting the specific gravity of fuel (Japanese Utility Model Application No. 62-1
No. 47036), a means for detecting fuel properties based on the ease of evaporation of fuel (Reed Vapor Pressure: RVP) determined from the fuel temperature and the rise time of pressure in the fuel tank (Japanese Utility Model Application No. 62-1161448) , a known fuel property detection means such as a means for detecting the pressure within a fuel tank may be used.

[Effects of the Invention] As described above, according to the present invention, when using heavy fuel, the corrected ignition advance angle at idle is changed to a lower value than when using non-heavy fuel. This has features such as being able to improve idle stability and preventing deterioration of idle stability due to overcorrection when non-heavy fuel is used.

[Brief explanation of drawings]

Figure 1 is a diagram showing the principle of the present invention, Figure 2 is a diagram showing the configuration of an embodiment of the present invention, Figure 3 is a diagram showing the hardware configuration of the microcomputer in Figure 2, and Figure 4 is a diagram showing fuel properties. A flowchart showing the coefficient calculation routine, FIG. 5 is a diagram showing the relationship between fuel property coefficients and fuel properties, FIG. 6 is a 70-chart showing an example of the correction constant calculation routine, and FIG. 7 is a correction ignition advance Flowchart showing one embodiment of the angle calculation routine, FIG. 8 is a diagram showing the relationship between the corrected ignition advance angle and rotational speed deviation calculated by the routine of FIG. 7, and FIG. 9 is a flowchart showing the ignition timing calculation routine. , FIG. 10 is a diagram showing a one-dimensional tube used in FIG. 89. DESCRIPTION OF SYMBOLS 10... Internal combustion engine, 11... Idle state detection means, 12...-Rotational speed detection means, 13...-Ignition timing calculation means, 14... Ignition means, 15... Fuel tank, 1
6...Fuel, 17...Fuel property detection means, 18...
- Correction ignition advance angle variable means, 21-... microcomputer, 26... idle switch, 41... rotation angle sensor, 49... vapor flow rate sensor. Figure 1

Claims (1)

[Scope of Claims] Idle state detection means for detecting that the internal combustion engine is in the idle state; rotation speed detection means for detecting the number of revolutions of the internal combustion engine; and detection that the engine is in the idle state by the idle state detection means. The basic ignition advance angle during idling is corrected by a correction ignition advance angle according to the deviation between the rotation speed and the target rotation speed so that the rotation speed detected by the rotation speed detection means becomes the target rotation speed when the rotation speed is reached. An ignition timing control device for an internal combustion engine, comprising an ignition timing calculation means for calculating the ignition timing based on the ignition timing, and an ignition means for igniting the internal combustion engine at a timing according to the ignition timing from the ignition timing calculation means, comprising: a fuel property detecting means for detecting the difficulty of evaporation of the fuel; and based on a detection signal from the fuel property detecting means, the corrected ignition advance angle is adjusted when the fuel is heavy fuel compared to when non-heavy fuel is used. An ignition timing control device for an internal combustion engine, comprising: a corrected ignition advance angle variable means for changing and setting the ignition advance angle to a larger value.