JP2006090220A - Output control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an output control device for an internal combustion engine, having a simple structure and capable of securely suppressing vibration at the time of stepping on an accelerator and at the time of return operation. <P>SOLUTION: Based on an accelerator opening (APS), a target throttle opening is calculated via a predetermined transfer function C (s) including a resonance frequency element and an attenuation coefficient element. At this time, the resonance frequency element and the attenuation coefficient element of the predetermined transfer function C (s) are varied in accordance with the accelerator opening (APS). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an output control device for an internal combustion engine, and more particularly to a technique for reducing vibration (acceleration / deceleration shock) during accelerator operation of a vehicle.

  In general, vibration (acceleration / deceleration shock) occurs when the accelerator of the vehicle is depressed or returned (particularly when the accelerator is depressed suddenly). Such acceleration / deceleration shock is caused by a sudden change in engine torque caused by a sudden accelerator depression or return operation, resulting in torsional vibration in the drive system. Such a torsional vibration of the drive system appears as a vibration phenomenon in the longitudinal direction of the vehicle body.

A method of slowly opening the throttle is widely known in order to suppress the vibration of the drive system that occurs due to such an accelerator operation. However, such a method impairs the feeling of acceleration.
For this reason, one of the applicants of the present application has proposed that a compensator is interposed upstream of the control input of the electronic throttle valve (ETV) to cancel the resonance of the drive system (in the middle of the torque rise). Has been proposed (Patent Document 1 and the like).
JP 2004-68702 A

However, even in the technique disclosed in Patent Document 1 above, it has been confirmed that a good compensation effect can be obtained in a region where the opening of the ETV is low, but vibration cannot be sufficiently suppressed in a region where the opening is high. It was done.
This phenomenon is deeply related to the characteristics of the ETV and the intake pipe through subsequent studies. In addition to the fact that a large amount of air passes through the ETV immediately after the ETV is greatly opened from the low intake pipe pressure, in particular, the intake pipe pressure It has been found that when the pressure exceeds the critical pressure, the ETV opening area and the passing air amount are not proportional and show non-linearity. In other words, it has become clear that the boost pressure (Pb) in the intake manifold cannot exceed the atmospheric pressure (Pa), which makes it difficult to sufficiently suppress vibration.

Thus, how to compensate the characteristics of the ETV and the intake pipe in order to surely suppress the vibration becomes a problem.
The present invention has been made to solve such problems, and an object of the present invention is to provide an output control device for an internal combustion engine that can reliably suppress vibrations when the accelerator is depressed or returned by a simple configuration. Is to provide.

  In order to achieve the above-mentioned object, the output control device for an internal combustion engine according to claim 1 is set to compensate for vibration of a secondary resonance system generated in the vehicle with respect to a change in accelerator opening, In an output control device for an internal combustion engine that controls a throttle opening using a predetermined transfer function including a coefficient element, an accelerator opening detecting means for detecting an accelerator opening and detected by the accelerator opening detecting means A target throttle opening calculating means for calculating a target throttle opening through the predetermined transfer function based on the accelerator opening, and a throttle opening based on the target throttle opening calculated by the target throttle opening calculating means A throttle opening adjusting means for adjusting the throttle opening, and the target throttle opening calculating means is an accelerator detected by the accelerator opening detecting means. And calculates a target throttle opening degree by varying the resonant frequency elements and the damping coefficient elements of the predetermined transfer function depending on the time.

That is, the target throttle opening is calculated through a predetermined transfer function based on the accelerator opening, and at this time, the resonance frequency element and the damping coefficient element of the predetermined transfer function are varied according to the accelerator opening, The target throttle opening is appropriately calculated so as to effectively suppress the torsional vibration of the drive system.
In the output control apparatus for an internal combustion engine according to claim 2, when ω _m is a resonance frequency, ζ _m is a damping coefficient, s is a Laplace operator, and A is a constant, the predetermined transfer function is (s ² + Aω _m s + ω _m ²⁾ a _{^{/ (s 2 + 2ζ m ω}} m s + ω m 2), the target throttle opening degree calculation means, small enough resonant frequency omega _m accelerator opening is large, increasing the damping factor zeta _m It is characterized by that.

That is, the resonance frequency ω _m of the transfer function consisting of (s ² + Aω _m s + ω _m ² ) / (s ² + 2ζ _m ω _m s + ω _m ² ) is decreased and the damping coefficient ζ _m is increased as the accelerator opening increases. Thus, the target throttle opening is appropriately calculated to more effectively suppress the torsional vibration of the drive system.
In the output control device for an internal combustion engine according to claim 3, when ω ₁ and ω ₂ are resonance frequencies, Kn is a proportional coefficient, and s is a Laplace operator, the predetermined transfer function is {s ² + (ω ₁ + Ω ₂ −ω ₁ × ω ₂ × Kn) s + ω ₁ × ω ₂ } / {s ² + (ω ₁ + ω ₂ ) s + ω ₁ × ω ₂ }, and the target throttle opening calculation means is an accelerator opening As the value increases, ω ₁ × ω ₂ decreases and Kn increases.

That is, as the accelerator opening increases, {s ² + (ω ₁ + ω ₂ −ω ₁ × ω ₂ × Kn) s + ω ₁ × ω ₂ } / {s ² + (ω ₁ + ω ₂ ) s + ω ₁ × ω ₂ } By reducing ω ₁ × ω ₂ of the transfer function and increasing the proportionality coefficient Kn, the target throttle opening is appropriately calculated so as to more effectively suppress the torsional vibration of the drive system.

According to the output control apparatus for an internal combustion engine of claim 1, the resonance frequency element and the damping coefficient element of the predetermined transfer function for calculating the target throttle opening are made variable according to the accelerator opening. It is possible to reliably suppress the torsional vibration of the drive system with an appropriate opening, and to suitably reduce unpleasant acceleration / deceleration shocks given to the vehicle occupant.
According to the output control apparatus for an internal combustion engine of claim 2, the resonance frequency ω of the transfer function consisting of (s ² + Aω _m s + ω _m ² ) / (s ² + 2ζ _m ω _m s + ω _m ² ) as the accelerator opening increases. small _m, by increasing the damping coefficient zeta _m, it is possible to reliably suppress the torsional vibration of the drive system of the target throttle opening degree as appropriate with a simple configuration.

According to the output control device for an internal combustion engine of claim 3, the larger the accelerator opening, the more {s ² + (ω ₁ + ω ₂ −ω ₁ × ω ₂ × Kn) s + ω ₁ × ω ₂ } / {s ² + Drive the target throttle opening to an appropriate value with a simple configuration by reducing ω ₁ × ω ₂ of the transfer function consisting of (ω ₁ + ω ₂ ) s + ω ₁ × ω ₂ } and increasing the proportionality coefficient Kn. The torsional vibration of the system can be reliably suppressed.

Hereinafter, an embodiment of an output control device for an internal combustion engine according to the present invention will be described with reference to the drawings.
The present invention is applied to an engine (gasoline engine) provided with a so-called electronic throttle valve (ETV, throttle opening adjusting means) in which an accelerator pedal and a throttle are electrically connected.

Referring to FIG. 1, a control model of a system including an output control device according to the present invention is shown in a block diagram.
According to the block diagram, in the control model, an operation amount of an accelerator pedal, that is, a signal from an accelerator opening sensor (APS, accelerator opening detecting means) 10 that detects an accelerator opening is an ECU (electronic control unit). It is input to a compensator (target throttle opening calculation means) 20 which is a part. When the signal from the compensator 20 is input to the ETV 30, the opening degree of the ETV 30 is controlled based on the output of the compensator 20. Then, the boost pressure Pb in the intake manifold 40 changes in accordance with the throttle opening signal from the throttle opening sensor (TPS) 35 and the engine rotational speed Ne, whereby the torque Te of the engine 50 changes, and the vehicle 60 The acceleration Acc changes.

In the block diagram, the transfer characteristic from the torque generation of the engine 50 by the boost pressure Pb to the acceleration Acc of the vehicle 60, that is, the transfer function G (s) of the system from the engine 50 to the vehicle 60 is simulated by a secondary resonance system. In this case, the transfer function is expressed as the following equation (1).
G (s) = Kω _p ² / s ² + 2ζ _p ω _p s + ω _p ² (1)
Here, s is a Laplace operator, and ω _p and ζ _p are the resonance frequency and damping coefficient of the system from the engine 50 to the vehicle 60, respectively. The resonance frequency f is actually ω / 2π and ω = 2πf. Hereinafter, for convenience, ω will be referred to as the resonance frequency.

Thus, when the transfer function G (s) from the torque generation of the engine 50 to the acceleration Acc of the vehicle 60 is set, the transfer function C (s) of the compensator 20 for suppressing the vibration of the secondary resonance system is The following equation (2) can be given (predetermined transfer function).
C (s) = (s ² + 2ζ _p ω _m s + ω _m ² ) / (s ² + 2ζ _m ω _m s + ω _m ² ) … (2)
Here, s is a Laplace operator, and ω _m and ζ _m are a resonance frequency and a damping coefficient in the compensator 20, respectively. Since ζ _p can be set to a constant, the 2ζ _p portion of equation (2) can be rewritten as A (constant).

In this equation, in a linear region where the boost pressure Pb in the intake manifold 40 does not exceed the atmospheric pressure Pa and the ETV opening area is proportional to the passing air amount, ω _m = ω _p and ζ _m is set to an appropriate value. Thus, a desired acceleration response in which torsional vibration (hereinafter simply referred to as vibration) of the drive system is suppressed can be obtained.
However, in the non-linear region where the boost pressure Pb in the intake manifold 40 exceeds the atmospheric pressure Pa and the ETV opening area and the passing air amount are not proportional to each other, an acceleration response that suppresses the vibration of the drive system is always obtained. I can't.

In this case, theoretically, if the resonance frequency ω _m and the damping coefficient ζ _m are made variable, an acceleration response in which the vibration of the drive system is satisfactorily suppressed can be obtained.
Specifically, in the nonlinear region, the resonance frequency ω _m is decreased and the damping coefficient ζ _m is increased as the accelerator opening (APS value) is increased. Actually, as shown in FIGS. 2 and 3, the relationship between the accelerator opening and ω _m , the accelerator input and ζ _m is previously mapped for each gear position of the transmission (not shown), and these maps are used. The resonance frequency ω _m and the damping coefficient ζ _m are read out from.

As a result, it is possible to obtain a good acceleration response that sufficiently suppresses vibration of the drive system at any accelerator opening, that is, a compensation effect, with a simple configuration.
Referring to FIG. 4, theoretical values of APS value, TPS value, boost pressure Pb, and acceleration Acc when the accelerator opening is changed from 6% to 30% are shown. Referring to FIG. 5, the accelerator opening is 6%. → The theoretical values of APS value, TPS value, boost pressure Pb, and acceleration Acc when increased to 80% are shown, and the solid line in the figure shows the resonance frequency ω _m and the damping coefficient ζ _m in FIG. The figure shows the case where it is variable according to the map, and the broken line shows the case where the resonance frequency ω _m and the damping coefficient ζ _m are constant. As shown in these figures, the resonance frequency ω _m and the damping coefficient ζ _m By making each of them variable according to the above map, the TPS response, that is, the torque that cancels the resonance of the drive system (the torque that once decreases during the torque rise) Generation can be controlled properly The vibration of the acceleration Acc can be attenuated to reliably suppress the vibration of the drive system.

Hereinafter, an actual design method in the actual vehicle of the compensator 20 as described above will be described.
Referring to FIG. 6, a compensator 20 according to the present invention is shown, and the configuration of the compensator 20 will be described below.
According to FIG. 1, the APS 10 is connected to the input side of the compensator 20, and the ETV 30 is connected to the output side.

The compensator 20 is configured as a feed-forward compensator (FF compensator) as shown by a block diagram in the figure, and realizes an equivalent system of the equation transfer function C (s) of the above equation (2). Accordingly, a proportional element 22, a first primary delay element 24, a second primary delay element 26, and a differential element 28 are provided. Specifically, the proportional element 22 is a proportional coefficient Kn, and the first primary delay element 24 and the second primary delay element 26 are respectively 1 / (s / ω ₁ +1) using the resonance frequencies ω ₁ and ω _2. 1 / (s / ω ₂ +1), and the differential element 28 is s.

The transfer function C (s) ′ of the block diagram of the equivalent system configured as described above is expressed by the following equation (3).
C (s) ′ = {s ² + (ω ₁ + ω ₂ −ω ₁ × ω ₂ × Kn) s + ω ₁ × ω ₂ }
/ {S ² + (ω ₁ + ω ₂ ) s + ω ₁ × ω ₂ } … (3)
Here, when the same equation (3) is compared with the above equation (2), (ω ₁ + ω ₂ −ω ₁ × ω ₂ × Kn) corresponds to 2ζ _p ω _m and ω ₁ × ω ₂ is equal to ω _m corresponds to ^2, it can be seen that corresponds to (ω ₁ + ω ₂₎ is 2ζ _m ω _m.

Thus, for example, if ω ₂ is fixed at 2π × 1 (rad / sec), the resonance frequency ω _m and the attenuation coefficient ζ _m can be changed, that is, ω ₁ and Kn can be made variable. I understand that it doesn't become.
Therefore, as shown in FIG. 7, the block diagram of FIG. 6 is further equivalently modified. As shown in FIGS. 8 and 9, the accelerator opening and ω _m are maintained so as to maintain the relationship between the accelerator opening and the resonance frequency ω _{m and} the relationship between the accelerator opening and the damping coefficient ζ _m shown in FIGS. _1. The relationship between the accelerator input and Kn is mapped in advance for each shift stage of a transmission (not shown) through experiments.

As a result, the ideal compensator 20 can be configured simply, and a good acceleration response with suppressed vibration of the drive system can be obtained at any accelerator opening.
10 to 12, when the accelerator opening is changed from 6% to 40%, from 6% to 80%, from 30% to 80%, the APS value, TPS value, boost pressure Pb, and the measured value of the acceleration Acc are shown, and Kn solid line omega ₁ and in Figure shows the case of the variable in accordance with the map of FIG. 8 and 9 show a case where the broken line is constant and omega ₁ and Kn However, as shown in these figures, by making ω ₁ and Kn variable according to the above map, the resonance frequency ω _m and the damping coefficient ζ _m are respectively shown in FIG. 2 by the transfer function C (s). 3 makes it possible to reproduce the above theoretical values in a variable manner according to the map in FIG. 3, regardless of the accelerator opening, a torque that cancels the TPS response, that is, the resonance of the drive system (once during the torque rise). (Such as a torque reduction) Accordingly, the response of the boost pressure Pb is smoothed, and the vibration of the acceleration Acc is attenuated, so that the vibration of the drive system can be surely suppressed.

Thereby, the unpleasant acceleration / deceleration shock given to the passenger | crew of the vehicle 60 can be reduced suitably.
In particular, in a vehicle equipped with a torque converter type automatic transmission (A / T) or continuously variable transmission (CVT) using a fluid coupling, a direct coupling mode in which the fluid coupling is directly coupled to achieve constant speed running stability. When the accelerator pedal is operated largely with the fluid coupling directly connected and sudden acceleration / deceleration is performed, the direct connection is generally released to avoid acceleration / deceleration shock. By applying, acceleration / deceleration shock can be suitably avoided without releasing the direct connection, and fuel consumption can be improved.

Although the description of the embodiment of the output control device for an internal combustion engine according to the present invention has been completed above, the embodiment is not limited to the above, and various modifications can be made without departing from the gist of the present invention.
For example, in the above embodiment, ω ₂ is fixed to 2π × 1 (rad / sec) and ω ₁ and Kn are made variable in the transfer function C (s) ′, but ω ₁ is fixed, ω ₂ and Kn can be made variable, and all of ω ₁ , ω _2, and Kn can be made variable.

It is a block diagram which shows the control model of the system containing the output control apparatus which concerns on this invention. It is a map which shows the relationship between an accelerator opening and (omega) _m . It is a map which shows the relationship between an accelerator input and (zeta) _m . It is a figure which shows the theoretical value of APS value, TPS value, boost pressure Pb, and acceleration Acc when the accelerator opening is changed from 6% to 30%. It is a figure which shows the theoretical value of APS value and TPS value, boost pressure Pb, and acceleration Acc when accelerator opening is enlarged from 6% to 80%. It is a figure which shows the compensator which concerns on this invention. It is the figure which equivalently deformed the block diagram of FIG. Is a map showing a relationship between the accelerator opening and the omega _1. It is a map which shows the relationship between an accelerator input and Kn. It is a figure which shows the measured value of APS value, TPS value, boost pressure Pb, and acceleration Acc when the accelerator opening is changed from 6% to 40%. It is a figure which shows the measured value of APS value, TPS value, boost pressure Pb, and acceleration Acc when the accelerator opening is 6% → 80%. It is a figure which shows the measured value of APS value, TPS value, boost pressure Pb, and acceleration Acc when the accelerator opening is changed from 30% to 80%.

Explanation of symbols

10 Accelerator position sensor (APS, accelerator position detector)
20 Compensator (Target throttle opening calculation means)
30 Electronic throttle valve (ETV, throttle opening adjustment means)
35 Throttle opening sensor (TPS)
40 intake manifold 50 engine 60 vehicle

Claims (3)

An internal combustion engine that controls the throttle opening using a predetermined transfer function that is set to compensate for vibrations of the secondary resonance system that occur in the vehicle against changes in the accelerator opening, and that includes a resonance frequency element and a damping coefficient element. In the engine output control device,
An accelerator opening detecting means for detecting the accelerator opening;
Target throttle opening calculating means for calculating a target throttle opening via the predetermined transfer function based on the accelerator opening detected by the accelerator opening detecting means;
Throttle opening adjustment means for adjusting the throttle opening based on the target throttle opening calculated by the target throttle opening calculation means,
The target throttle opening calculation means calculates a target throttle opening by varying a resonance frequency element and a damping coefficient element of the predetermined transfer function according to the accelerator opening detected by the accelerator opening detection means. An output control device for an internal combustion engine characterized by the above. When ω _m is a resonance frequency, ζ _m is a damping coefficient, s is a Laplace operator, and A is a constant,
The predetermined transfer function is (s ² + Aω _m s + ω _m ² ) / (s ² + 2ζ _m ω _m s + ω _m ² ),
The target throttle opening degree calculation means, small enough resonant frequency omega _m accelerator opening is large, characterized by increasing the attenuation coefficient zeta _m, output control device for an internal combustion engine according to claim 1. When ω ₁ and ω ₂ are resonance frequencies, Kn is a proportional coefficient, and s is a Laplace operator,
The predetermined transfer function is {s ² + (ω ₁ + ω ₂ −ω ₁ × ω ₂ × Kn) s + ω ₁ × ω ₂ } / {s ² + (ω ₁ + ω ₂ ) s + ω ₁ × ω ₂ } ,
_2. The output control apparatus for an internal combustion engine according to claim 1, wherein the target throttle opening calculation means decreases ω ₁ × ω ₂ and increases Kn as the accelerator opening increases.

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