JP3438362B2 - Control device for internal combustion engine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an internal combustion engine which discriminates between a steady state and an accelerated state of the internal combustion engine and controls the internal combustion engine accordingly.

[0002]

2. Description of the Related Art For example, in an outboard motor engine, a large torque is required from an extremely low speed range, and therefore sufficient torque cannot be obtained unless the ignition timing is advanced in conjunction with throttle operation during acceleration. Therefore, conventionally, a link mechanism for advancing the ignition timing in conjunction with the throttle is provided, or a throttle sensor for detecting the throttle opening is provided for the throttle, and the sensor signal is processed by a microcomputer to obtain the ignition timing. Are trying to control.

However, if a complicated link mechanism or throttle sensor for advancing the ignition timing in conjunction with the throttle operation is provided, the structure becomes complicated and the cost becomes high. Particularly, in the case of the link mechanism, a complicated adjusting function is required. It is necessary and has the drawback of degrading maintainability.

Further, when the ignition timing is controlled only by controlling the throttle opening, the ignition timing required in the steady state of the engine is different from the required ignition timing in the accelerated state, but in the conventional configuration described above, the steady state is set. Since the same ignition timing control is performed regardless of the acceleration state, for example, if the ignition timing control is performed with reference to the acceleration state, the optimum ignition timing cannot be obtained in the steady state.

Therefore, as shown in Japanese Patent Laid-Open No. 63-205462, the amount of change in the engine speed for each reference crank angle is converted into the amount of change in the number of revolutions per unit time to determine the acceleration / deceleration of the engine. There is one in which the ignition timing is corrected according to the determination result.

[0006]

However, in the structure described in the above publication, the acceleration / deceleration of the engine is determined by the instantaneous amount of change in the number of revolutions per unit time. Is effective, but there is a disadvantage that acceleration is erroneously determined in a region where the rotation speed fluctuation is large such as idle. Also, even when the acceleration continues continuously, its rotation contains a slight pulsation,
The pulsation of rotation may be erroneously determined as deceleration during acceleration, and it is difficult to continuously detect the state in which acceleration continues.

The present invention has been made in consideration of such circumstances, and therefore an object thereof is to make accurate acceleration determination from the amount of change in the rotational speed of the internal combustion engine, and to use the determination result as the internal combustion engine. An object of the present invention is to provide a control device for an internal combustion engine, which can be reflected in the control of.

[0008]

In order to achieve the above object, a control device for an internal combustion engine according to claim 1 of the present invention comprises a change amount detecting means for periodically detecting a change amount of the rotational speed of the internal combustion engine, Integrating means for integrating the rotational speed change amount, acceleration determining means for determining whether or not the vehicle is in an acceleration state based on the integrated value of the rotational speed change amount, and the internal combustion engine according to the determination result of the acceleration determining means. And a control means for changing the operating state of the engine.

In this structure, it is preferable that the integrating means includes a reset means for resetting the integrated value when the rotational speed change amount indicates deceleration.

In this case, the reset means may reset the integral value when the deceleration state continues for a predetermined time. Further, as in claim 4, the control means may control the ignition timing of the internal combustion engine.

Alternatively, as in claim 5, the control means switches the ignition timing of the internal combustion engine between an acceleration ignition timing and a steady ignition timing in accordance with the determination result of the acceleration determination means, and the acceleration is performed. The ignition timing may be advanced from the steady-state ignition timing in the low rotation speed region.

[0012]

According to the first aspect of the present invention, the rotational speed change amount of the internal combustion engine is periodically detected by the change amount detection means, and the rotational speed change amount is integrated by the integration means. Then, the acceleration determining means determines whether or not the vehicle is in an accelerating state based on the integrated value of the rotational speed change amount. For example, it is determined whether or not the vehicle is in an accelerating state depending on whether or not the integrated value of the rotational speed change amount exceeds a predetermined value, and the operating means of the internal combustion engine is changed by the control means according to the determination result. In this case, since the acceleration determination is performed by the integrated value of the rotational speed change amount, unlike the above-described known example, it is not affected by the instantaneous rotation fluctuation (pulsation) of the internal combustion engine, and accurate acceleration determination can be performed. Become.

Further, according to a second aspect of the present invention, the integrated value of the rotational speed change amount is reset by the reset means when the rotational speed change amount indicates deceleration. As a result, the integration of the rotational speed change amount can be started from the end of deceleration as the starting point, and the influence of the rotational speed change in the deceleration direction can be eliminated.

In the third aspect, the condition for resetting the integrated value of the rotational speed change amount is that the deceleration state continues for a predetermined time. Therefore, if the deceleration state ends within a predetermined time, the integral is continued without resetting the integral value of the rotational speed change amount. As a result, instantaneous rotation fluctuation (pulsation)
It is possible to continue the integration of the rotational speed change amount without being affected by.

On the other hand, in claim 4, the ignition timing of the internal combustion engine is controlled according to the determination result of the acceleration determination means, but the acceleration determination means is also used for other control of the internal combustion engine such as fuel injection control and intake air amount control. The determination result may be reflected. By using the determination result of the acceleration determination means for ignition timing control,
It is possible to control the ignition timing by distinguishing between the steady state and the accelerated state.

Further, in claim 5, the ignition timing is switched between the ignition timing for acceleration and the ignition timing for steady state according to the determination result of the acceleration determining means. In this case, by advancing the ignition timing at the time of acceleration from the ignition timing at the steady time in the low rotation speed region, the torque is increased during acceleration to improve the acceleration performance.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to an ignition timing control device will be described below with reference to the drawings. As shown in FIG. 1, the control device 11 includes a one-chip microcomputer 12 having a built-in ROM / RAM (not shown), and a drive circuit for driving an ignition coil 13 by an ignition signal output from the microcomputer 12. 14 and a waveform shaping circuit 16 for shaping the pulse signal output from the crank angle sensor 15 and inputting it to the microcomputer 12.
It consists of and. The crank angle sensor 15 is attached to a crankshaft or the like of an engine (internal combustion engine) (not shown), outputs a pulse signal of a constant angular cycle (for example, 15 ° C cycle) in synchronization with the rotation of the engine, and outputs a specific crank signal. The pulse signal is cut at the position and used for cylinder discrimination. The present embodiment is an embodiment for controlling the ignition timing of a three-cylinder engine. Therefore, the drive circuit 14 and the ignition coil 13 in the control device 11 are provided for three cylinders.

RO of the microcomputer 12 described above
M stores various programs for engine control such as ignition control, an ignition cycle start routine shown in FIG. 2, and an acceleration determination routine shown in FIG. The ignition cycle starting routine of FIG. 2 is repeatedly executed in an ignition cycle, and for example, in the case of a three-cylinder engine, it is executed in a 120 ° C. cycle. In this routine, first, at step 101, the engine speed calculation subroutine is called, and the crank angle sensor 1
The engine speed NE is calculated from the signal generation cycle of No. 5.
For this calculation, an angular cycle corresponding to the angle of the ignition cycle is measured and used. For example, in the case of three cylinders, the engine speed is calculated using the rotation time of 120 ° C. It is optimum that the calculation of the engine speed is performed in the ignition cycle, and if it is performed in a cycle shorter than this cycle (for example, 15 ° C. or 60 ° C. A), it is affected by the intra-cycle rotation fluctuation, and the engine speed When calculating the change amount, the change amount is different from the actual change amount, and the normal change amount cannot be determined.

After calculating the engine speed NE, step 1
02, in order to determine the acceleration state of the engine,
In an acceleration determination processing routine shown in FIG. 3, which will be described later, it is determined whether the operating state of the engine is an accelerating state or a steady state, and the acceleration determination flag XACCF is set to 1 or 0 depending on the operating state of the engine.
Set to. After that, the routine proceeds to step 103, and the reference ignition timing AACCB at the time of acceleration corresponding to the engine speed at that time is calculated from the acceleration time ignition timing table stored in advance in the ROM of the microcomputer 12. Next, the routine proceeds to step 104, where the steady-state reference ignition timing ABSE corresponding to the engine speed at that time is calculated from the steady-state ignition timing table stored in advance in the ROM. The ignition timing for acceleration and the ignition timing for steady state are set to have an ignition timing characteristic as shown in FIG. 4, and the ignition timing for acceleration is advanced from the ignition timing for steady state in a low rotation region (for example, a region of 2300 rpm or less). It is set to obtain the highest torque within the allowable limit of knocking.

Next, the routine proceeds to step 105, where it is determined whether the operating condition of the engine is the accelerating condition or the steady condition.
It is determined whether or not the ACCF is 1, and if the acceleration determination flag XACCF is 0 (steady), step 106
And the ignition timing AESA is changed to the reference ignition timing A in the steady state.
Set BSE. On the other hand, the acceleration determination flag XACCF
Is 1 (acceleration), the routine proceeds to step 107, where the ignition timing AESA is set to the reference ignition timing AACCB during acceleration. The processing of steps 106 and 107 functions as control means for changing the operating state of the engine (ignition timing in this embodiment) according to the result of the acceleration determination (step 105).

After setting the ignition timing AESA, step 10
8 to perform various ignition timing correction control (for example, knocking control and correction of the angle of the crank angle sensor 15 serving as a reference), and then to step 109, in order to generate an ignition signal at a predetermined angle, The process of converting the angle into time is performed, the ignition timing is set in the timer, and this routine is ended.

Next, the processing contents of the acceleration determination processing routine executed in step 102 will be described with reference to the flowchart of FIG. First, in step 201, the engine speed change amount DELNE is calculated by the following equation.

DELNE = NE-NEOLD NE: latest engine speed NEOLD: previous engine speed The process of step 201 functions as a change amount detecting means in the claims. After the change amount calculation, the latest engine speed NE is set to NEOL for the next change amount calculation.
Store and hold as D. After that, the routine proceeds to step 202, where it is determined whether the change in the engine speed is in the deceleration direction or the acceleration direction, based on whether the change amount DELNE is smaller than 0 or not. If the change amount DELNE is 0 or more (change in the acceleration direction), the process proceeds to step 203 and the change amount DR
LNE is integrated (integrated), and the change amount integrated value DNEINT is calculated by the following equation.

DNEINT = DNEINT + DRLNE The processing of step 203 functions as an integrating means for integrating the rotational speed change amount in the claims. Deceleration generation counter CACC after calculation of rotation speed change amount DNEINT
After clearing D, the process proceeds to step 208. here,
The deceleration generation counter CACCD is a counter that counts the number of continuous rotation speed changes in the deceleration direction (rotation speed change amount DELNEH <0).

On the other hand, in step 202, the change amount DELNE
When is smaller than 0 (that is, when decelerating), the routine proceeds to step 204, where the state of the acceleration determination flag XACCF is checked. If the acceleration determination flag XACCFCF is 1, that is, if the previous time is the acceleration state and the current time is the deceleration state, the process proceeds to step 205 and the deceleration occurrence counter CAC
The CD is counted up, and the process proceeds to step 206. In this step 206, the deceleration occurrence counter CAC
It is determined whether or not CD (the number of continuous changes in the number of revolutions in the deceleration direction) is greater than a preset number of times KCACD.
Is larger than KCACCD, the routine proceeds to step 207, where the deceleration generation counter CACCD is cleared, the integral value DNEINT of the change amount is reset, and the routine proceeds to step 208.

On the other hand, when the acceleration determination flag XACCF is 0 in step 204, that is, when the previous deceleration state is also determined, the process proceeds to step 207 and the deceleration occurrence counter CACCD and the integral value DNEINT of the change amount are reset. Then, the process proceeds to step 208. The processing of steps 202 to 207 described above functions as a reset unit that resets the integrated value DNEINT of the change amount when the rotational speed change amount DELNE is in the negative state (that is, the deceleration state) for a predetermined time.

On the other hand, in step 208, the change amount integrated value DNEINT is set to the preset determination value KDNEINT.
Acceleration judgment is performed by comparing with the change amount integrated value DNEIN
If T is larger than the determination value KDNEINT, it is determined that the vehicle is in an accelerated state, and the acceleration determination flag XA is determined in step 210.
Set CCF to 1. On the other hand, the change amount integrated value D
If NEINT is less than or equal to the determination value KDNEINT, it is determined to be in a steady state, and the acceleration determination flag X is determined in step 209.
Clear the ACCF (XACCF = 0). The processing of these steps 208 to 210 functions as the acceleration determination means in the claims. With the above processing, the acceleration determination routine ends.

There are two kinds of set values used in this acceleration judgment routine, namely, a deceleration occurrence counter judgment value KCACCD and an acceleration judgment value KDNEINT of the change amount integrated value.
These are values to be set for each engine, and in this embodiment, they are set as follows. KCACCD = 1 KDNEINT = 300 rpm With this setting, in this embodiment, the change amount integrated value DNEI
When NT exceeds 300 rpm, it is determined to be in an accelerated state,
Further, the change amount integrated value DNEINT is reset when the determination that the rotation speed change amount DELNE is in the negative state (that is, the deceleration state) continues twice (240 ° C. in crank angle).

An example of the case where the ignition timing control described above is performed will be described with reference to the time charts shown in FIGS. 5 and 6. In FIGS. 5 and 6, (a) is the acceleration determination flag XACCF, and (b) is the rotational speed variation integrated value DN.
EINT, (c) shows the engine rotational speed NE, (d) shows the ignition timing AESA, and (e) shows the rotational speed change amount DELNE.

First, in FIG. 5, when the throttle is opened and the operating state of the engine becomes the accelerating state, the engine speed NE starts to increase. As a result, the change amount DELNE of the engine speed in the acceleration direction is detected, and the change amount integrated value DNEINT increases. This change amount integrated value DNE
When INT becomes larger than the acceleration determination value KDEINT, it is determined that acceleration has occurred, and the acceleration determination flag XACC
Set F to 1. Along with this, ignition timing AESA
Is switched from the ignition timing setting during steady state to the ignition timing setting during acceleration, and the ignition timing is greatly advanced. While the acceleration continues, the acceleration determination flag is maintained at 1 and the ignition timing is controlled by the ignition timing set value at the time of acceleration. When the acceleration is completed and the engine shifts to the steady state, the acceleration determination flag XACCF is cleared and the ignition timing is switched to the ignition timing setting for the steady state.

FIG. 6 is a time chart showing in detail the change when acceleration occurs from the steady state (idle). In the steady state (idle), the engine speed is relatively unstable, and changes in the acceleration direction may occur multiple times in succession. However, the change in the deceleration direction has been repeated a predetermined number of times
Since the change amount integrated value DNEINT is reset when D (for example, twice) continuously occurs, the change amount integrated value DN is maintained during the steady state (idle) as shown in FIG. 6B.
EINT never exceeds the acceleration judgment value KDNEINT.

Thereafter, when acceleration occurs, the amount of change in the number of revolutions DELNE per one time is large, and the change in the increasing direction continuously occurs. As a result, the change amount integrated value DNEIN
T rapidly increases and exceeds the acceleration determination value KDNEINT, at which point it is determined that the vehicle is in an accelerating state and the acceleration determination flag XACCF is set to 1. In the latter half of acceleration, changes in the acceleration direction are shown on average, but changes in the deceleration direction may occur in each cycle. However, if the change in the deceleration direction does not occur continuously for a predetermined number of times KCACC D (for example, 2), the change amount integrated value DNEINT is not reset, and the acceleration determination continues. As a result, it is possible to quickly determine the occurrence of acceleration, and it is possible to maintain the determination state until the acceleration ends.

In this way, in the present embodiment, the acceleration state and the steady state can be discriminated only by the pulse signal having a constant angular period output from the crank angle sensor 15 in a cycle of the engine rotation. Therefore, it is not necessary to provide a complicated link mechanism or a throttle sensor for advancing the ignition timing at the time of acceleration, so that the configuration can be simplified and the cost can be reduced. Moreover, since the ignition timing control value is switched by switching the ignition timing setting value according to the acceleration state and the steady state, it is possible to control the ignition timing optimal for the acceleration state and the steady state, regardless of the operating state of the engine. The optimum ignition timing control can always be performed, and engine performance can be improved.

In this embodiment, step 10
After calculating the ignition timing from the ignition timing table at the time of acceleration and at the time of steady state at 3 and 104, at steps 105 and 107,
The acceleration timing ignition timing or the steady time ignition timing is used depending on the state of the acceleration determination flag XACCF. However, each ignition timing calculation subroutine is called after determining the state of the acceleration determination flag XACCF. May be.

Further, in this embodiment, the pulse signal of the 15 ° C. cycle outputted from the crank angle sensor 15 is used, but the pulse signal of the number of cylinders (ignition cycle) and the cylinder discrimination signal are used. May be.

In addition, the present invention is not limited to the ignition timing control, but the determination result of the acceleration determination may be reflected in other engine control such as fuel injection control and intake air amount control. The present invention can be applied to the control of any engine such as an automobile, a two-wheeled vehicle, an inboard motor, etc., as well as an engine for a machine, and of course, the present invention can be applied to any two-cycle engine, four-cycle engine, and the number of cylinders Needless to say.

[0037]

As is apparent from the above description, according to the control device for an internal combustion engine of claim 1 of the present invention, the acceleration determination is performed by the integrated value of the rotational speed change amount of the internal combustion engine. Acceleration judgment can be performed without being affected by instantaneous rotation fluctuation (pulsation), accurate acceleration judgment can be performed, and it is not necessary to provide a complicated link mechanism or throttle sensor, and the configuration can be simplified. Therefore, the cost can be reduced.

Further, in claim 2, since the integrated value of the rotational speed change amount is reset when the rotational speed change amount indicates deceleration, the integral of the rotational speed change amount is started from the end of deceleration. It is possible to start, and it is possible to eliminate the influence of the change in the rotation speed in the deceleration direction.

In the third aspect, if the deceleration state ends within a predetermined time, the integral is continued without resetting the integral value of the rotational speed change amount, so that there is no influence of the instantaneous rotational fluctuation (pulsation). It is possible to continue the integration of the rotational speed change amount. On the other hand, according to the fourth aspect, since the ignition timing of the internal combustion engine is controlled according to the acceleration determination, it is possible to perform the ignition timing control that distinguishes between the steady state and the accelerated state.

Further, according to claim 5, the ignition timing is switched between the ignition timing for acceleration and the ignition timing for steady state according to the acceleration determination, and the ignition timing for acceleration is advanced from the ignition timing for steady state in the low rotation speed region. Therefore, it is possible to control the ignition timing optimal for the acceleration state and the steady state, and to advance the ignition timing during acceleration to increase the torque.
The acceleration performance can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram of a control system showing an embodiment of the present invention.

FIG. 2 is a flowchart showing a processing flow of an ignition cycle starting routine.

FIG. 3 is a flowchart showing a processing flow of an acceleration determination routine.

FIG. 4 is a diagram showing characteristics of steady-state ignition timing and acceleration-timing ignition timing.

FIG. 5 is a time chart (1) showing an example of control according to the present invention.

FIG. 6 is a time chart showing an example of control according to the present invention (part 2).

[Explanation of symbols]

11 ... Control device, 12 ... Micro computer (change amount detection means, integration means, acceleration determination means, control means, reset means), 13 ... Ignition coil, 15 ... Crank angle sensor.

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Claims (5)

(57) [Claims] 1. A change amount detecting means for periodically detecting a rotational speed change amount of an internal combustion engine, an integrating means for integrating the rotational speed change amount, and an acceleration state based on an integrated value of the rotational speed change amount. An internal-combustion-engine control device comprising: acceleration determining means for determining whether or not there is any; and control means for changing an operating state of the internal combustion engine according to a determination result of the acceleration determining means. 2. The control device for an internal combustion engine according to claim 1, wherein the integrating means has a reset means for resetting the integrated value when the rotational speed change amount indicates deceleration. . 3. The control device for an internal combustion engine according to claim 2, wherein the reset means resets the integrated value when the deceleration state continues for a predetermined time. 4. The control device for an internal combustion engine according to claim 1, wherein the control means controls an ignition timing of the internal combustion engine. 5. The control means switches the ignition timing of the internal combustion engine between an acceleration ignition timing and a steady ignition timing in accordance with a determination result of the acceleration determination means, and sets the acceleration ignition timing in a low rotation speed region. The control device for an internal combustion engine according to claim 4, wherein the ignition timing is advanced from the steady-state ignition timing.