JP2612386B2 - Supercharging pressure detection device for supercharged 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 supercharging pressure detecting device for detecting a supercharging pressure for various controls such as air-fuel ratio correction in an internal combustion engine having a supercharger such as a turbocharger. .

[0002]

2. Description of the Related Art In an internal combustion engine with a supercharger, a supercharging pressure is generally detected by using a supercharging pressure sensor in order to perform an air-fuel ratio correction or the like corresponding to the supercharging pressure. Since the pressure sensor is adversely affected by the vibration, a supercharging pressure sensor is usually supported on the vehicle body side of the automobile, and the supercharging pressure is guided from the intake system of the internal combustion engine to the supercharging pressure sensor via a pipe.

On the other hand, when a supercharging pressure sensor is connected via a pipe as described above, an air column vibration occurs in the pipe during a steady state, especially in a high load range, so that the detected pressure value vibrates and accurate detection can be performed. Absent. Therefore, it is common practice to sample the output of the supercharging pressure sensor at regular intervals and obtain a weighted average to eliminate the influence of air column vibration. Also, during acceleration, it is necessary to detect a rise in the boost pressure with good response.Therefore, the acceleration is determined from the rate of change of the throttle opening, and the weight coefficient of the weighted average is changed between during acceleration and during steady state. ing. That is, the weighted average _{P AV} of the supercharging pressure P obtains a sampling value P, _{P AV} weighted average of previous 'and the weight coefficient and _{W, P AV = P · W} + P AV' as · (1-W) However, when accelerating, the weight coefficient W is set to a relatively large value to ensure follow-up to acceleration changes, and when steady, the weight coefficient W is set to a relatively small value to eliminate the influence of air column vibration. It is.

[0004]

However, in an internal combustion engine with a supercharger such as a turbocharger, there is a delay in response to a change in supercharging pressure. Even after it is determined that the pressure has been increased, the supercharging pressure continues to increase. Therefore, if the steady-state weight coefficient W given at this time is set to be small, it is impossible to follow the rise of the supercharging pressure, and appropriate control cannot be performed. On the other hand, if the weighting coefficient W in the steady state is set to be large, the influence of the air column vibration is increased.

[0005]

Accordingly, a supercharging pressure detecting device according to the present invention, as shown in FIG. 1, has a supercharging pressure sensor attached via a pipe to an intake system of a supercharged internal combustion engine. 1, sampling means 2 for sampling the detection value of the supercharging pressure sensor 1 at regular intervals, first weighted averaging means 3 for calculating a weighted average of the sampling values using a first weighting coefficient, Second weighted averaging means 4 for calculating the weighted average of the sampled values using a second weighting coefficient
Acceleration detecting means 5 for detecting that the internal combustion engine is in an accelerating state based on a change in throttle opening, weighted average by the first weighted average means 3 and weighted by the second weighted average means 4 A supercharging pressure increase period detecting means 6 for comparing the average with the average to detect that the internal combustion engine is in a supercharging pressure increase period after the end of acceleration. And a third weighted averaging means 7 for calculating a supercharged pressure by calculating a weighted average of the sampled values using predetermined weighting factors corresponding to the respective periods. And

[0006]

When it is determined that the internal combustion engine is accelerating from the change in the throttle opening, a small value is given as a weighting coefficient of the weighted average for detecting the boost pressure. In a completely steady state, a sufficiently large value is given as a weight coefficient, and the influence of air column vibration is eliminated. Then, if it is determined that the boost pressure period is after acceleration, a weight coefficient of an intermediate magnitude is given, and the boost pressure can be followed. The determination as to whether or not the boost pressure period is after acceleration is made by comparing the weighted average by the first weighted average means 3 with the weighted average by the second weighted average means 4.
That is, while the boost pressure is increasing, the respective weighted averages have different values. In a completely steady state, each weighted average is an approximate value. Thereby, it is possible to accurately grasp whether the supercharging pressure is actually increasing.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 2 is an explanatory view of the configuration of an internal combustion engine provided with a supercharging pressure detecting device according to the present invention, in which a turbocharger 14 is provided between an intake passage 12 and an exhaust passage 13 of an internal combustion engine 11.
Is provided, and an air flow meter 15 is disposed upstream of the compressor 14 a in the intake passage 12. Further, a throttle valve 16 is provided downstream of the compressor 14a in the intake passage 12, and at a position downstream of the throttle valve 16,
A supercharging pressure sensor 18 is connected via a pipe 17.
The throttle valve 16 is provided with a throttle valve opening sensor 19 for detecting its opening. 20 is the internal combustion engine 11
A crank angle sensor 21 for detecting the rotational speed of the engine is a control unit for performing various controls of the internal combustion engine 11 such as a fuel injection amount and an ignition timing. Various corrections and the like are performed based on the correction.

FIG. 3 is a flowchart showing the flow of the supercharging pressure detection process executed in the control unit 21. This process is repeatedly executed, for example, at a constant time or at a constant crank angle. First, in step 1, the detection value P of the boost pressure sensor 18 and the throttle opening T
The VO is read, and in step 2, an acceleration determination is made based on the rate of change ΔTVO of the throttle valve opening TVO. here,
If the acceleration and determined as shown in (a) of FIG. 4, the process proceeds to step 8 to select the largest W ₃ as the weighting factor W. Therefore, the weighted average in the next step 9 is
It performed using the weighting factor W _3, thereby an output which follows a good response to the boost pressure change is obtained. On the other hand, if it is determined in step 2 that it is other than acceleration, steps 3 to 5 are further performed.
It is determined whether the supercharging pressure is increasing. That is, two weighted averages P _AV1 and P _AV2 are obtained using the weight coefficient W ₁ and the weight coefficient W ₂ (steps 3 and 4),
It is determined in step 5 whether or not they substantially match.
As shown in FIG. 4 (b), in a completely steady state, the two weighted averages P _AV1 and P _AV2 have approximate values, and during the boost pressure increase, they have different values. That is, it is determined whether the operation is in the steady state or not. Boost pressure based on the comparison of step 5 is the case it is determined that the rising, the process proceeds to step 6, select the weighting factor W ₂ of intermediate size. Also if the supercharging pressure is not increased, the process proceeds to step 5 it is determined that a complete steady state selects a smaller weight coefficient W _1.

In step 8, a new weighted average _PAV is calculated by using the weighting coefficient W, the sampled value P, and the previous weighted average value _PAV 'as _PAV = PW + _PAV '. (1-W). I do. Note that the weighted averages P _AV1 and P _AV2 are obtained by the same calculation.

According to the configuration in which the weight coefficient W is changed in three stages as described above, as shown by the broken line in FIG. In this state, the influence of air column vibration can be sufficiently eliminated. In particular, even if the boost pressure rise period after the end of acceleration changes depending on operating conditions or the like, the actual rise in the boost pressure is sequentially detected from the comparison between the two weighted averages P _AV1 and P _AV2 . The optimum weighting coefficient W can be set in a form that correctly corresponds to the actual boost pressure rise period.

[0012]

As is apparent from the above description, according to the supercharging pressure detecting device for a supercharged internal combustion engine according to the present invention, the supercharging pressure rising period during steady state, during acceleration and after acceleration of the engine. And the weighted average is calculated using the appropriate weighting factors. Therefore, it is possible to detect the increase in the supercharging pressure following the completion of the acceleration determination due to the response delay of the turbocharger and the like with good response. In addition, it is possible to more reliably eliminate the influence of air column vibration that occurs during a steady state. Also, relatively large air column vibrations can be tolerated, and restrictions on the mounting position of the supercharging pressure sensor are reduced. In particular, even if the boost pressure rise period after the end of acceleration changes depending on operating conditions or the like, the actual rise in the boost pressure is sequentially detected from the comparison of the two weighted averages. An optimal weighting factor can be set in a form that correctly corresponds to the rising period. Moreover, there is no influence of pulsation when detecting the boost pressure rising period.

[Brief description of the drawings]

FIG. 1 is a claim correspondence diagram showing a configuration of the present invention.

FIG. 2 is a configuration explanatory view showing one embodiment of a supercharging pressure detecting device according to the present invention.

FIG. 3 is a flowchart illustrating a flow of a process of detecting a supplementary pressure.

FIG. 4 is a time chart showing an example of a change in supercharging pressure and the like.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Supercharging pressure sensor 2 ... Sampling means 3 ... First weighted averaging means 4 ... Second weighted averaging means 5 ... Acceleration detecting means 6 ... Supercharging pressure rise period detecting means 7 ... Third weighted averaging means

Claims (1)

(57) [Claims] 1. A supercharging pressure sensor attached to an intake system of a supercharged internal combustion engine via a pipe, and a sampling means for sampling a detection value of the supercharging pressure sensor at regular intervals. First weighted averaging means for calculating a weighted average of the sampled values using a first weighting coefficient;
Calculating the weighted average of the weighting values using the second weighting factor
2 means that the internal combustion engine is accelerating.
Acceleration detection means for detecting based on a change in throttle opening,
The weighted average by the first weighted averaging means and the second weight
Boost pressure rises to detect that the internal combustion engine by comparing the weighted average by the averaging means is in the supercharging pressure increase period after the end of acceleration
Period detection means, based on these detections, categorizes into a boost period and a boost pressure period during steady state, during acceleration, and after acceleration, and adds the above sampling value using a predetermined weighting coefficient corresponding to each.
Third weighted averaging means for calculating a weighted average and obtaining a supercharging pressure
And a supercharging pressure detecting device for a supercharged internal combustion engine.