JPH07197828A - Idling rotational speed controller of internal combustion engine - Google Patents

Abstract

PURPOSE:To improve controllability of idling rotational speed of an internal combustion engine by setting a target output torque and target throttle opening by an output torque found out from the condition of an engine and a load torque necessary for outer load drive preliminarily stored so as to feed-forward control it, when an outer load is applied. CONSTITUTION:Output torque TE of an engine is estimated by an output torque estimation means (e) from engine rotational speed NE and throttle opening TVO. Load torque RTE is read out preliminarily from an outer load torque memory means (g) for storing the load torque RTE necessary for the outer load drive when application of the outer load is detected by an outer load detection means (f), and target output torque TES is calculated by a target output torque calculation means (h) from the estimated engine output torque TE and the load torque RTE. Target throttle opening TVOS is set from the target output torque TES by a target throttle opening feed forward setting means (i) in stead of a target throttle opening feedback set means (a) during a required period from the time when the outer load is applied.

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 internal combustion engine using an electronic throttle valve control device.

[0002]

2. Description of the Related Art Conventionally, as an idle speed control device for an internal combustion engine using a single-valve type electronic throttle valve control device having no auxiliary intake system, Japanese Patent Laid-Open No. 1-271 has been proposed.
The one disclosed in Japanese Patent No. 636 is known. In this engine, normally, during idle operation, the engine speed is compared with the target idle speed, and the drive signal (current value) to the throttle valve drive actuator is feedback-controlled to match them, and the throttle opening (Throttle valve opening) is controlled. Then, when the operation of the external load (air conditioner, power steering, etc.) is detected, the feedback control is stopped for a predetermined period, and the target drive signal (current value to the actuator) according to the external load is set, and the control by this is performed. It is switching.

[0003]

However, when an external load is applied and the target drive signal is simply determined and controlled according to the external load, the state of the engine is not taken into consideration at all, and the temperature, the power supply voltage, etc. are not taken into consideration. Are susceptible to changes in the operating environment of the system and changes in the system over time, require non-linear corrections, and in order to control the engine speed, which is the final control target, experimentally when each external load is input. However, there is a problem that it is necessary to accurately obtain the drive signal value.

In view of such conventional problems, an object of the present invention is to improve the idle speed control when an external load is applied.

[0005]

Therefore, according to the present invention, as shown in FIG. 1, a target throttle opening degree is set to be increased or decreased in a direction in which the engine speed is compared with a target idle speed to make them match. An idle speed control device for an internal combustion engine, which comprises throttle opening feedback setting means a and throttle valve control means b for driving and controlling the throttle valve so that the set target throttle opening and the actual throttle opening match. In, the following means c to i are provided.

[0006] The engine speed detecting means c is configured to detect the engine speed (N
E) is detected. The throttle opening detection means d detects the throttle opening (TVO). Output torque estimating means e
Estimates the output torque (TE) of the engine from the detected engine speed (NE) and throttle opening (TVO). The external load detection means f detects that an external load has been applied.

The load torque storage means g stores a load torque (RTE) required to drive an external load and gives it. The target output torque calculation means h calculates the target output torque (TE) from the engine output torque (TE) estimated by the output torque estimation means e and the load torque (RTE) given by the load torque storage means g.
S) is calculated.

The target throttle opening feedforward setting means i replaces the target throttle opening feedback setting means a for a predetermined period from the time when an external load is applied, and replaces the target throttle opening feedback setting means a with the engine speed detected by the engine speed detecting means c. The target throttle opening (TVOS) is set from the number (NE) and the target output torque (TES) calculated by the target output torque calculating means h.

Further, as shown by a dotted line in FIG. 1, it is preferable to provide a correcting means j of the load torque (RTE) applied from the load torque storing means g to the target output torque calculating means h. As shown in FIG. 2, the correction means j is composed of the following means j-1 to j-3.

The engine rotational speed storage means j-1 at the time of load entry is
The engine speed (NE ₀ ) at the time when an external load is applied is stored. The engine speed maintaining output torque estimating means j-2 is an output required to maintain the engine speed from the engine speed (NE ₀ ) at the time when an external load is applied and the current throttle opening (TVO). Estimate the torque (TE ₁ ).

The load torque correcting means j-3 has a current output torque (T) estimated by the output torque estimating means e.
E) and the engine speed maintenance output torque estimating means j-2
Engine speed maintenance output torque (TE ₁ ) estimated by
Then, the load torque correction amount is calculated, and the load torque (RTE) from the load torque storage means g is temporarily corrected.

Further, as shown by a dotted line in FIG. 1, a load torque (RTE) updating means k stored in the load torque storing means g may be provided. As shown in FIG. 3, the updating means k is composed of the following means k-1 to k-3. The load-torque output torque storage means k-1 stores the output torque (TE ₀ ) of the engine estimated by the output torque estimation means e when an external load is applied.

The load torque calculating means k-2 has a current output torque (TE) estimated by the output torque estimating means e after a predetermined period has elapsed from the time when the external load is applied.
And the output torque (TE) at the time when the external load stored by the load rush output torque storage means k-1 is applied.
₀ ) and the load torque (RTE) is calculated. The load torque updating means k-3 calculates the calculated load torque (RT
The stored value of the load torque storage means g is rewritten by E).

[0014]

In the above construction, the engine state, that is, the output torque of the engine obtained from the engine speed and the throttle opening, and the load torque required to drive the external load stored in advance are used. A target throttle opening degree is set so that an output torque sufficient to cancel the load torque is further output when an external load is applied. As a result, the engine speed can be quickly converged to the target idle speed in consideration of the state of the engine.

Further, the output torque required to maintain the engine speed is estimated from the engine speed at the time when an external load is applied and the current throttle opening, and the load is calculated from this and the current output torque. The torque correction amount is calculated and the load torque from the load torque storage means is temporarily corrected. Thereby, the load torque according to the external load can be made more appropriate.

Further, after a lapse of a predetermined period from the time when the external load is applied, that is, when the engine speed converges near the target idle speed, the output torque at the time when the external load is applied and the current output torque are calculated. The load torque is calculated by calculation, and the stored value of the load torque storage means is updated.
As a result, stable control becomes possible at the next load rush.

[0017]

EXAMPLE An example of the present invention will be described below. FIG. 4 shows the system configuration. Reference numeral 1 is a microprocessor unit, 2 is an input unit for taking in signals from various sensors and A / D converters, 3 is an output unit for outputting control signals, and 4 is a memory for storing programs and data.

Reference numeral 5 is an accelerator sensor for detecting an accelerator opening (amount of depression of an accelerator pedal), 6 is a throttle sensor as a throttle opening detecting means for detecting a throttle opening, and 7 is an engine speed for detecting an engine speed. A crank angle sensor as a detection means, 8 is a power steering switch as an external load detection means provided as a trigger for increasing the output of the engine when a load of a hydraulic pump for power steering is applied, and 9 is an accelerator sensor 5 or A / which converts the voltage value from the throttle sensor 6 into a digital value
It is a D converter.

Reference numeral 10 is a motor as an actuator for driving a throttle valve, 11 is a battery, 12 is a relay for controlling motor energization, 13 is a transistor for relay control, and 14-17.
Is a transistor for controlling the motor conduction direction, and 18 is a resistor. Here, by turning on the transistor 13,
The relay 12 is closed to supply current to the motor 10. At this time, by turning on the transistors 14 and 17, the direction of the current flowing through the motor 10 is, for example, the throttle valve opening direction, and the transistors 15 and 16 are turned on. By turning on and, the direction of the current flowing through the motor 10 is set to, for example, the throttle valve closing direction.

FIGS. 5 and 6 are flowcharts of the idle speed control routine executed by the microprocessor unit 1 at a predetermined cycle during idle operation. In step 1 (denoted as S1 in the figure, the same applies hereinafter),
The external load is detected, and the type of load is set in the flag R. Specifically, as shown in FIG. 7, it is determined whether or not the power steering switch is ON (S101), R = 0 is set when the power steering switch is OFF (S102), and R = when the power steering switch is ON. It is set to 1 (S103). Although only one type of external load is used here, a plurality of types may be used.

In step 2, the value of the flag R is set to the previous value (1
It is determined whether R ≠ R ₀ (the type of external load has changed) by comparing with the value R ₀ (before the cycle), and if R ≠ R ₀ , the current engine speed NE is loaded in step 3. It is stored as the engine speed NE ₀ at the time of turning on. This portion corresponds to the engine rotational speed storage means upon load application. At step 4, since it is the next time, the value of the present flag R is substituted into R ₀ .

In step 5, it is determined whether the flag R ≠ 0 (external load is applied). [When no external load is applied] When no external load is applied (when R = 0), the process proceeds from step 5 to step 22.

In step 22, a count value C, which will be described later, is set.
Reset _FWD to 0. Then, the routine proceeds to step 23, where the current engine speed NE and the target idle speed NES
When NE ≧ NES, the target throttle opening TVOS is set to the predetermined value ΔTVO with respect to the current value in step 24.
If NE <NES, the target throttle opening TVOS is increased by a predetermined amount ΔTVO with respect to the current value in step 25. This part corresponds to the target throttle opening feedback setting means.

Then, the routine proceeds to step 26, where the motor drive time TIME required to displace the throttle valve from the current throttle opening TVO to the target throttle opening TVOS is calculated according to the following equation. This portion corresponds to the throttle valve control means. TIME = (TVOS-TVO) × K (where K is a constant) When the motor drive time TIME is a positive value,
During that time, the throttle valve is driven in the opening direction, and in the case of a negative value, the throttle valve is driven in the closing direction during that time. [When external load is applied] When external load is applied (when R ≠ 0), step 5 to step 6
Go to.

In step 6, the absolute value of the deviation between the engine speed NE and the target idle speed NES | NE-NES |
Is greater than the threshold TH. This is to determine whether or not feedforward control is necessary based on the deviation between the two. When | NE-NES |> TH,
The feedforward control is considered necessary at the time of load rush, and the process proceeds to step 7. When | NE-NES | ≤TH, it is considered that the feedforward control is unnecessary, and the routine proceeds to step 19.

In step 7, it is determined whether or not the count value C _FWD indicating the number of times the feedforward control is performed is zero. As a result, if C _FWD = 0, the process proceeds to step 8, and if C _FWD ≠ 0, the process proceeds to step 12. In step 8, the output torque TE of the engine is obtained by referring to the map from the current engine speed NE and the current throttle opening TVO. The map used here is obtained by experimentally storing the output torque of the engine with respect to the engine speed and the throttle opening. This portion corresponds to the output torque estimating means.

In the next step 9, the output torque TE obtained in step 8 is stored as the output torque TE ₀ at the time of load inrush. This portion corresponds to the output torque storage means upon load inrush. In the next step 10, the load torque storage means (RA) that stores the load torque RTE required to drive the external load according to the value of the flag R (type of external load).
The stored value of the load torque RTE corresponding to the value of the flag R is read from M) and the load torque RTE is set. Specifically, as shown in FIG. 8, it is determined whether or not the flag R = 1 (S1001), and when R = 0, RTE = 0 is set (S100).
2) When R = 1, RTE = MRTE (S100
3).

In the next step 11, the count value C _FWD indicating the number of times the feedforward control is performed is set to 1 and
Go to step 17. In step 17, the target output torque TES is calculated by adding the load torque RTE to the current output torque TE as in the following equation. This portion corresponds to the target output torque calculation means.

TES = TE + RTE In the next step 18, the target throttle opening TVOS is obtained from the current engine speed NE and the target output torque TES by referring to the map. The map used here may be the one used in step 8, and it may be read in reverse. This portion corresponds to the target throttle opening feedforward setting means.

After this, the routine proceeds to step 26, where the motor drive time TIME required to displace the throttle valve from the current throttle opening TVO to the target throttle opening TVOS is TIME = (TVOS-TVO).
Calculate K. If C _FWD ≠ 0 in the determination in step 7, the process proceeds to step 12, and it is determined whether C _FWD = 1.
As a result, if C _FWD = 1 then proceed to step 13
_{If FWD} ≠ 1 (C _FWD = 2), go to step 23.

Therefore, after the feedforward control for the first time is performed, the feedforward control for the second time is performed, so that the process proceeds to step 13. In step 13, the output torque TE of the engine is obtained by referring to the map from the current engine speed NE and the current throttle opening TVO. The map used here is also the one used in step 8. This part also corresponds to the output torque estimating means.

In the next step 14, the output torque required to maintain the engine speed by referring to the map from the engine speed NE ₀ at the time of load entry and the current throttle opening TVO stored in step 9 (Engine speed maintenance output torque) TE ₁ is calculated. The map used here is also the one used in step 8. This portion corresponds to the engine speed maintaining output torque estimating means.

In the next step 15, the difference between the current output torque TE and the engine speed maintenance output torque TE ₁ is calculated as in the following equation, and this is calculated as the load torque correction amount (TE-T).
E ₁ ), the load torque RTE is corrected by subtracting the load torque correction amount (TE-TE ₁ ) from the load torque RTE given from the load torque storage means. This portion corresponds to the load torque correction means.

RTE = RTE- (TE-TE ₁ ) At the next step 16, the count value C _FWD indicating the number of times the feedforward control is performed is set to 2, and the _routine proceeds to step 17. In step 17, as described above, the load torque RTE (however, after correction) is added to the current output torque TE to calculate the target output torque TES = TE + RTE. In the next step 18, as described above, the target throttle opening TVOS is set from the current engine speed NE and the target output torque TES. Then, the process proceeds to step 26, and as described above, the motor drive time TIME = (TVO required to displace the throttle valve from the current throttle opening TVO to the target throttle opening TVOS.
Calculate S-TVO) * K.

C _FWD ≠ 1 (C _FWD
= 2), go to step 23. Therefore, after the second feedforward control is performed, the feedback control is performed, and thus the process proceeds to step 23. In step 23,
As described above, the current engine speed NE is compared with the target idle speed NES. If NE ≧ NES, the target throttle opening TVOS is decreased in step 24, and NE <
In case of NES, in step 25 the target throttle opening TV
Increase OS. Then, the process proceeds to step 26, and as described above, the motor drive time TIME = (TVOS-TV required to displace the throttle valve from the current throttle opening TVO to the target throttle opening TVOS.
Calculate O) × K.

After the engine speed NE has converged to the vicinity of the target idle speed NES by the two times of feedforward control and the subsequent feedback control, | NE-NES | ≤TH is determined in step 6 by the judgment. Therefore, go to step 19. At step 19, the current engine speed N
The output torque TE of the engine is searched from E and the current throttle opening TVO by referring to the map. The map used here is also the one used in step 8. This part also corresponds to the output torque estimating means.

In the next step 20, the load torque RTE is calculated by subtracting the output torque TE ₀ upon load inrush stored in step 9 from the current output torque TE as in the following equation. This part corresponds to the load torque calculating means. RTE = TE-TE _{0 In the} next step 21, the stored value in the load torque storage means is rewritten with the load torque RTE calculated in step 20. Specifically, as shown in FIG. 9, flag R = 1
It is determined whether or not (S21O1), and if R = 1, the calculated load torque RTE is set as the stored value MRTE (S2102).
This part corresponds to the load torque updating means.

At the next step 22, the count value C _FWD indicating the number of times the feedforward control is performed is cleared to 0, and the _routine proceeds to step 23. In step 23, as described above, the current engine speed NE and the target idle speed NES
When NE ≧ NES, the target throttle opening TVOS is decreased in step 24, and when NE <NES, the target throttle opening TVOS is increased in step 25. Then proceed to step 26 and, as described above,
Target throttle opening T from current throttle opening TVO
The motor drive time TIME = (TVOS−TVO) × K required to displace the throttle valve to VOS is calculated.

[0039]

As described above, according to the present invention, in the idle speed control using the electronic throttle valve control device, the output torque obtained from the state of the engine is stored in advance when an external load is applied. The target output torque is set from the load torque required to drive the external load, the target throttle opening is set based on this, and feedforward control is performed to set the engine speed to the target speed. It is possible to quickly converge.

Further, the output torque required to maintain the engine speed is estimated from the engine speed at the time when an external load is applied and the current throttle opening, and the load is estimated from this and the current output torque. By calculating the torque correction amount and temporarily correcting the load torque from the load torque storage means, the load torque according to the external load can be made more appropriate.

Furthermore, after a lapse of a predetermined period from the time when the external load is applied, that is, when the engine speed converges near the target idle speed, the output torque at the time when the external load is applied and the current output torque are calculated. By calculating the load torque by calculation and updating the stored value of the load torque storage means, stable control can be performed at the next load rush.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing the configuration of the present invention.

FIG. 2 is a functional block diagram of correction means in FIG.

FIG. 3 is a functional block diagram of updating means in FIG.

FIG. 4 is a system configuration diagram showing an embodiment of the present invention.

FIG. 5 is a flowchart (part 1) of an idle speed control routine.

FIG. 6 is a flowchart of an idle speed control routine (No. 2)

FIG. 7 is a flowchart showing the specific contents of S1 of FIG.

FIG. 8 is a flowchart showing the specific contents of S10 of FIG.

FIG. 9 is a flowchart showing the specific contents of S21 of FIG.

[Explanation of symbols]

 1 Microprocessor unit 5 Throttle sensor 7 Crank angle sensor 8 Power steering switch 10 Motor

Claims (3)

[Claims] 1. A target throttle opening feedback setting means for comparing an engine speed with a target idle speed and increasing / decreasing a target throttle opening in a direction to make them coincide with each other, a set target throttle opening and an actual throttle opening. In an idle speed control device for an internal combustion engine, which comprises a throttle valve control means for driving and controlling a throttle valve so that the throttle opening coincides, an engine speed detecting means for detecting an engine speed and a throttle opening are detected. Throttle opening detection means, output torque estimation means for estimating the output torque of the engine from the detected engine speed and throttle opening, external load detection means for detecting that an external load has been applied, and external load Load torque storage means for storing the load torque required to drive the motor, and the output torque estimation means Target torque calculation means for calculating a target output torque from the output torque of the engine and the load torque given by the load torque storage means, and the target throttle opening feedback setting for a predetermined period from the time when an external load is applied. In place of the means, a target throttle opening feedforward setting means for setting a target throttle opening from the engine speed detected by the engine speed detecting means and the target output torque calculated by the target output torque calculating means, An idle speed control device for an internal combustion engine, comprising: 2. A load rush engine speed storage means for storing the engine speed at the time when an external load is applied, as a means for correcting the load torque applied from the load torque storage means to the target output torque calculation means. An engine speed maintaining output torque estimating means for estimating an output torque required to maintain the engine speed from the engine speed at the time when an external load is applied and the current throttle opening, and the output torque estimating means. From the estimated current output torque and the engine speed maintenance output torque estimated by the engine speed maintenance output torque estimation means, a load torque correction amount is calculated, and the load torque from the load torque storage means is calculated. The idling speed control device for an internal combustion engine according to claim 1, further comprising: a load torque correcting means for correcting. 3. A load rush output torque memory that stores the output torque of the engine estimated at the time when an external load is applied by the output torque estimating means as the load torque updating means stored in the load torque storing means. Means, and after a predetermined period has elapsed from the time when the external load is applied, the current output torque estimated by the output torque estimating means and the time when the external load stored by the load inrush output torque storage means is applied. The load torque calculating means for calculating the load torque from the output torque, and the load torque updating means for rewriting the stored value of the load torque storage means by the calculated load torque are provided. Alternatively, the idle speed control device for an internal combustion engine according to claim 2.