JP2002130102A - Idle engine speed controller for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an idle engine speed controller for an engine capable of preventing a racing-up of engine speed when starting during idling without stepping on an accelerator pedal and only by clutch operation. SOLUTION: This idle engine speed controller for the engine has a feedback means performing feedback control of ignition timing so that the engine speed converges into an idle target engine speed during idling, a lower limit guard means regulating a feedback control variable of the ignition timing by the feedback means or a final ignition timing calculated on the basis of the feedback control variable by a predetermined lower limit guard of a retard side, a starting state detecting means detecting a starting state, an air capacity increasing means increasing an intake air capacity a predetermined amount when the starting state is detected by the starting state detecting means, and a lower limit guard changing means enlarging the lower limit guard of the lower limit guard means to the retard side a predetermined value when the starting state is detected by the starting state detecting means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an idle speed control device for an engine, and more particularly, to an idle speed control device for an engine that performs feedback control of an ignition timing so as to converge an engine speed to an idle target speed during idling operation. It relates to a control device.

[0002]

2. Description of the Related Art Conventionally, as an engine idle speed control device, for example, as disclosed in Japanese Patent Publication No. 7-92037, the engine speed is converged to an idle target speed during idling operation. A device that performs feedback control of the ignition timing is known. In this publication, a lower limit guard and an upper limit guard are set on the retard (advance) side and the advance (advance) side, respectively, with respect to the feedback control amount of the ignition timing, and the feedback range of the ignition timing is set. Regulations are underway to prevent engine stalls. Note that the lower limit guard on the retard side has a smaller value as the absolute value of the intake air charge amount is larger.

[0003]

On the other hand, when a driver drives a manual vehicle (manual transmission vehicle) on a congested road or the like, the driver operates the clutch without depressing the accelerator pedal (with no accelerator). The vehicle may be started. However, if the operation cannot be performed satisfactorily, such an operation may cause the engine rotation to drop and cause engine stall. In order to prevent the engine speed from dropping due to such an operation, it is conceivable to increase the amount of intake air when starting in such a no-accelerator state. However, if the intake air is simply increased, when the load of the transmission is not applied to the engine in the half-clutch state, the increase in the intake air becomes excessive, and the engine speed increases. This increase in engine speed is suppressed by the feedback control of the ignition timing, but since the lower limit guard is set for the feedback control amount of the ignition timing as described above,
It was found that the ignition timing could not be sufficiently retarded to the retard side as needed, and it was found that the feedback control of the ignition timing alone could not solve the engine speed increase due to the increased intake air.

Accordingly, the present invention provides an idle speed control device for an engine which can prevent the engine speed from rising when the vehicle is started only by operating the clutch without depressing the accelerator pedal during idling. It is intended to be.

[0005]

To achieve the above object, an engine idle speed control apparatus according to the present invention comprises:
Feedback means for performing feedback control of the ignition timing so that the engine speed converges to the idle target speed during the idling operation; and feedback control amount of the ignition timing by the feedback means or the final ignition timing calculated based on the feedback control amount. Lower limit guard means for regulating with a predetermined lower limit guard on the retard side, start state detection means for detecting the start state, and air amount increase for increasing the intake air amount by a predetermined amount when the start state is detected by the start state detection means Means, and a lower limit guard changing means for expanding the lower limit guard of the lower limit guard means to the predetermined value retard side when the starting state is detected by the starting state detecting means.

In the present invention having the above-described structure, when the engine is idling, usually, the ignition timing is feedback-controlled so that the engine speed converges to the idle target speed. At this time, by regulating the feedback control amount of the ignition timing by the feedback means or the final ignition timing calculated based on the feedback control amount by the predetermined lower limit guard on the retard side, the ignition timing is excessively retarded and an engine stall occurs. I try to prevent it. On the other hand, when the vehicle is in the starting state at the time of idling, the intake air amount is increased by a predetermined amount, so that the engine speed may be increased. At this time, the lower limit guard is extended to the predetermined value retard side. Therefore, the ignition timing can be retarded more than the lower limit guard, so that the engine speed can be prevented from rising.

In the present invention, the starting state detecting means may determine that the vehicle is in the starting state when it detects that the engine speed has become equal to or lower than a set speed set at a predetermined value lower than the idle target speed. preferable. In the present invention, it is preferable that the air amount increasing means sets the increase value of the intake air amount such that a rotation speed higher than the idle target rotation speed is obtained. Further, the present invention preferably further comprises a retard means for retarding the ignition timing by a predetermined value so that the engine speed is maintained at the idle target speed when the intake air is increased by the air amount increasing means.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings. First, an overall configuration of an engine idle speed control device according to an embodiment of the present invention will be described with reference to FIG. An intake passage 2 and an exhaust passage 4 are connected to the engine 1. From the upstream side, the intake passage 2 has an air cleaner 6, an air flow sensor 8 for detecting an intake air amount, a throttle valve 10 for adjusting an intake air amount in conjunction with an accelerator pedal (not shown), and bypassing the throttle valve 10. A bypass valve 12, provided as
An electromagnetic injector 14 is provided for each cylinder. Further, a throttle sensor 16 for detecting the opening degree of the throttle valve, and an idle switch 18 for turning ON when the throttle valve 10 is fully closed (when the accelerator pedal is not depressed) to detect an idle operation of the engine 1.
Is provided.

A pressure regulator 20, a fuel pump 22, and a fuel tank 24 are connected to the injector 14, and the fuel in the fuel tank 24 is supplied at a predetermined pressure. Further, a water temperature sensor 26 for detecting the temperature of the cooling water of the engine 1, a rotation speed sensor 28 for detecting the engine speed, and a cam angle sensor 29 for detecting the cam angle of a supply / exhaust valve (not shown) are also provided. . Also,
An ignition plug 30 is provided for each cylinder of the engine 1.

On the other hand, an oxygen sensor 32 for detecting the oxygen concentration in the exhaust gas, a catalyst device 34 for purifying harmful components in the exhaust gas, and a
An oxygen sensor 36 is provided for jointly detecting deterioration of the catalyst device 34 with the oxygen sensor 32. Further, a clutch switch 37 for detecting whether the clutch is in a neutral state in which the clutch is on (not engaged) or in a gear-in state in which the clutch is off (engaged) is provided on the clutch (not shown) side. Further, an external load 40 is provided, and the external load 40 includes electric loads such as an air conditioner, a transmission (shift to a D range), and an all-in-allator. Reference numeral 38 denotes a control unit. The control unit 38 reads signals from the various sensors described above, the clutch switch 37, and the external load 40, and controls the throttle valve 10, the injector 14, and the like based on these signals, and ignites. This is for controlling the ignition timing of the plug 30 and the like.

Next, the contents of feedback control for setting the engine speed to the target idle speed during idling will be described with reference to FIGS. First, FIG.
And FIG. 6, the idle start flag (xidsta)
Will be described. In FIG. 2, “S” indicates each step. In FIG. 2, in S1, it is determined whether or not the engine coolant temperature is equal to or higher than a predetermined value (for example, 70 ° C.). If the water temperature is low, the process proceeds to S2, and the idle start flag (xidsta) is set to "0". this is,
FIG. 6 shows a state before time t ₁ . Next, if the water temperature is equal to or higher than the predetermined value, the process proceeds to S3, where the engine speed (ne) is set to a predetermined value (KSNIDST),
rpm is determined. If the engine speed is not equal to or greater than the predetermined value, the vehicle is started only by operating the clutch without depressing the accelerator pedal (no accelerator state). Therefore, such a state is determined to be the start state, and S4 Proceed to. In S4, the idle start flag (xidsta) is set to “1”. This is because, in FIG. 6, in the state of time t ₁ ~t _2.

Next, in S3, if the engine speed is equal to or more than the predetermined value, the process proceeds to S5, where it is determined whether or not the ISC first increased air amount (cedrnl) is "0" (see FIG. 6). If it is not "0", the process proceeds to S4, and the idle start flag (xidsta) is set to "1". This is because, in FIG. 6, in the state of time t ₂ ~t _4. The ISC first additional air amount (cedrnl) will be described later in detail. Next, in S5, if the first increased air amount for ISC (cedrnl) is "0", the increase of the intake air by the first increased air amount for ISC has been completed, so the process proceeds to S2. Idle start flag (xi
dsta) is set to “0”. This is because, in FIG. 6, in the state of time t ₄ later. Thus, FIG.
The idle start flag (xidsta) shown in FIG.

Next, referring to FIGS. 3, 4 and 6, the increase value (ce) of the intake air amount in the starting state during the idling operation will be described.
The setting routine of dr) will be described. In FIG. 3, "S" indicates each step. First, in S10, it is determined whether or not an idle start flag (xidsta) is “1”. If it is not "1", that is, if it is "0", the process proceeds to S11 and the clutch switch (xgrin)
Is "1". Here, when the clutch switch (xgrin) is “0”, the clutch is on (not engaged).
And "neutral" which is in a half-clutch state,
“1” indicates “gear-in” in which the clutch is off (engaged), and these states are determined by a signal from the clutch switch 37. If the idle start flag (xidsta) is not "1", that is, if it is "neutral", the process proceeds to S12. In S12, it is determined whether or not the idle start flag (xidsta) is "1". In this case, since it is "0", the process proceeds to S13, and the second increase for ISC indicating the actual increase in intake air. The air amount (cedr) is set to “0”. This is the state before time t ₁ in FIG.

Next, in S10, when it is determined that the idling start flag (xidsta) is "1", the process proceeds to S14, where the ISC first increased air amount (cedr) is set.
nl). Here, the first increased air amount (cedrnl) for ISC is calculated by the following equation.

Cedrnl = TICEDRM * {(KI
NIDSTH-ne) / (KINDISTH-KINI
DSTL)}

Here, TICEDRM is a correction amount (increase in intake air) set according to the vehicle speed.
DSTH is a predetermined engine speed (for example, 650 rpm) in the vicinity of the engine speed (KSNIDST) for determining the starting state at the time of starting the no-accelerator (see FIG. 4). Similarly, KINIDSTL is also predetermined. (For example, 550 rpm) (see FIG. 4). FIG. 4 shows (KINIDTH-ne) / (KIN
FIG. 4 is a diagram showing a relationship between (IDSTH-KINIDSTL) and the engine speed. (KINIDTH-ne) /
(KINIDSTH-KINIDSTL) is a correction amount (increase in intake air) set according to the vehicle speed (TICED
RM) is a coefficient (0 to 1) that is multiplied by RM). When the engine speed is between KINIDSTH to KINIDSTL,
The value is between 0 and 1 and the engine speed is KINIDS
When the engine speed is equal to or lower than TL, the value is “1”, and the engine speed is KI.
When it is equal to or more than NIDSTH, it becomes "0" and the amount of intake air is not increased. Thus, IS
A first increased air amount (cedrnl) for C is calculated.

Next, the program proceeds to S11, in which it is determined whether or not the clutch switch (xgrin) is "1". If it is determined that the value is "0", that is, "neutral", the program proceeds to S12. . In S12, it is determined whether or not the idle start flag (xidsta) is "1". In this case, since it is "1", the process proceeds to S15, and the second increase for ISC indicating the actual increase in intake air is performed. Air volume (ced
r) is set to “cedrnl” which is the first increased air amount for ISC calculated in S14. This is shown in FIG.
It is a state of time t ₁ ~t _3.

Next, if it is determined in step S11 that the clutch switch (xgrin) is "1", that is, "gear-in", the process proceeds to step S16, where the ISC for indicating the actual increase of the intake air is used. Second increased air volume (cedr)
Is set to “TICEDRM”. Here, "TICE
"DRM" is an increase in the intake air set according to the vehicle speed. This is because, in FIG. 6, in the state of time t ₃ or later. In this manner, the actual increase in the intake air in the starting state at the time of idling, that is, the second increased air amount for ISC (ce)
dr) is determined. In the present embodiment, the increase in the intake air is set so that the engine speed is higher than the idle target speed.

Next, a routine for setting the final ignition timing (thtig) during the idling operation will be described with reference to FIGS. In FIG. 5, "S" indicates each step. First, in S20, the ignition timing (TMPIG) is calculated. The ignition timing (TMPIG) is obtained by adding the coolant temperature correction amount and the starting retard amount (thtides) to the basic ignition timing.
ta), and is calculated by adding a correction amount such as an external load correction amount. The basic ignition timing is a value set according to the engine speed and the load, and the starting retard amount (thidstst).
a) is a value for maintaining the engine rotation speed higher than the idle target rotation speed at the idle target rotation speed due to the increase in the intake air when the intake air intake amount is increased. In the present embodiment, the ignition timing (TMPIG)
However, feedback control is performed such that the engine speed converges to the idle target speed during idling.

Next, the program proceeds to S21, in which the ignition timing (TMPI
It is determined whether or not G) is ahead of the advance-side upper limit guard (KATHTX).
To set the final ignition timing (thtig) to the upper limit guard (KATHTX). Next, in S21,
In the case of NO, the process proceeds to S23, in which it is determined whether or not the idle start flag (xidsta) is "1". If not, the process proceeds to S24, in which the clutch switch (xg
rin) is later than the lower limit guard (KATHTN) on the retard side. If YES, S
Proceeding to 25, the final ignition timing (thtig) is set to the lower limit guard (KATHTN).

Next, in step S23, when it is determined that the idle start flag (xidsta) is "1", the process proceeds to step S23.
Proceed to 26 and set the clutch switch (xgrin) to "1"
It is determined whether or not. In the case of "1", it is "gear-in", so it proceeds to S24, and in the case of "0", it is "neutral", so it proceeds to S27. As described above, on condition that the idling start flag (xidsta) is “1” and the clutch switch (xgrin) is “neutral”, the ignition timing (TMPI
G) is extended lower limit guard (K
(ATHIDST) is determined.
If YES, the process proceeds to S28 and the final ignition timing (tht
ig) is set as the expansion lower limit guard (KATHIDST).

Next, in S24, NO and S
27, that is, when the ignition timing (TMPIG) is set to the advance-side upper limit guard (KATH
TX), and the lower limit guard (K
ATHTN) or extended lower limit guard (KATHIDST)
If it is more advanced, that is, if it is within the feedback range, the process proceeds to S29, and the final ignition timing (thtig) is set to the ignition timing (TMPIG) calculated in S20.

In this embodiment, the ignition timing is feedback-controlled so that the engine speed converges to the idle speed.
IG) feedback control amount lower limit guard (KATH
TN) and the expansion lower limit guard (KATHIDST), but the final ignition timing (thtig) is controlled by the lower limit guard (KATHTN) and the expansion lower limit guard (KA).
THIDST).

According to the above-described embodiment, when the engine is idling, the ignition timing (TMPI) is usually set so that the engine speed (ne) converges to the idle target speed.
G) is feedback-controlled. At this time, the feedback control amount of the ignition timing or the final ignition timing calculated based on the feedback control amount is based on the advance upper limit guard (KATHX) and the retard side lower limit guard (K
ATHTN). Thereby, in the feedback control of the ignition timing, the occurrence of engine stall is prevented. On the other hand, when the vehicle is in the starting state at the time of idling, specifically, when the vehicle starts only by operating the clutch without depressing the accelerator pedal, the intake air amount is increased by a predetermined amount. The ignition timing can be retarded more than the lower limit guard because it has been changed to the lower limit guard expanded to the predetermined value retard side, thereby preventing the engine speed from rising due to the increase in the intake air amount can do.

[0025]

As described above, according to the engine idle speed control apparatus of the present invention, when the vehicle is started only by operating the clutch without depressing the accelerator pedal during idling, the engine speed increases. Can be prevented.

[Brief description of the drawings]

FIG. 1 is an overall schematic diagram showing an embodiment of an engine idle speed control device of the present invention.

FIG. 2 is a flowchart showing a routine for setting an idle start flag (xidsta) in one embodiment of the present invention.

FIG. 3 is a flowchart illustrating a routine for setting an increase value (cedr) of an intake air amount in a start state during idling according to an embodiment of the present invention.

FIG. 4 is a flow chart showing (K) used in the setting routine of FIG.
INIDSTH-ne) / (KINIDSTH-KIN
FIG. 3 is a diagram showing a relationship between (IDSTL) and an engine speed.

FIG. 5 is a flowchart illustrating a routine for setting a final ignition timing (thtig) during idle operation according to an embodiment of the present invention.

FIG. 6 is a time chart showing the content of an engine idle speed control according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Intake passage 8 Air flow sensor 10 Throttle valve 14 Injector 16 Throttle sensor 18 Idle switch 28 Speed sensor 37 Clutch switch 38 Control unit 40 External load

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) F02D 43/00 301 F02P 5/15 K E M (72) Inventor Kenji Tanaka 3 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture No. 1 Mazda Motor Corporation F-term (reference) 3G022 CA00 CA03 DA02 DA10 EA05 FA04 GA05 GA08 GA09 GA20 3G084 BA06 BA17 CA03 DA00 EA11 EB11 FA07 FA10 FA20 FA30 FA33 3G093 AA05 CA04 CB05 DA01 DA05 DA06 DA07 DA09 DA11 DB10 DB11 DB11 DB10 EC01 FA04 FA11 FB01 FB02 3G301 JA03 KA07 KB01 LA00 LA04 ND01 NE01 NE12 NE17 NE19 PA01Z PA11Z PA14Z PD09Z PE01A PE01Z PE03Z PE08Z PF06Z PF08Z PF10Z

Claims (4)

[Claims] A feedback means for performing feedback control of an ignition timing so that an engine speed converges to an idle target speed during an idling operation, and a feedback control amount of an ignition timing by the feedback means or a feedback control amount calculated based on the feedback control amount. Lower limit guard means for regulating the final ignition timing by a predetermined lower limit guard on the retard side; starting state detecting means for detecting the starting state; and a predetermined amount of intake air when the starting state is detected by the starting state detecting means. Air amount increasing means for increasing, and lower limit changing means for expanding the lower limit guard of the lower limit guard means to a predetermined value retard side when the starting state is detected by the starting state detecting means. Engine idle speed control device. 2. The vehicle according to claim 1, wherein the start state detecting means detects the start state when detecting a state in which the engine speed becomes equal to or lower than a set speed set at a predetermined value lower than the idle target speed. Engine idle speed control device. 3. The engine idle speed control device according to claim 2, wherein the air amount increasing means sets the increase value of the intake air amount such that a rotational speed higher than the idle target rotational speed is obtained. 4. The engine according to claim 3, further comprising a retard means for retarding the ignition timing by a predetermined value so that the engine speed is maintained at the idle target speed when the intake air is increased by the air amount increasing means. Idle speed control device.