WO2013175588A1

WO2013175588A1 - Device for estimating air intake volume for supercharged engine

Info

Publication number: WO2013175588A1
Application number: PCT/JP2012/063189
Authority: WO
Inventors: 高橋　真知子; 龍太郎森口
Original assignee: トヨタ自動車株式会社
Priority date: 2012-05-23
Filing date: 2012-05-23
Publication date: 2013-11-28

Abstract

The purpose of the present invention is to precisely calculate intake air volume, which fluctuates with atmospheric pressure, with a device for estimating air intake volume for a supercharged engine without using an atmospheric pressure sensor. In order to achieve this purpose, the device for estimating air intake volume according to this invention measures the actual intake channel pressure by way of a pressure sensor disposed at a prescribed position in the intake channel, which is from the compressor to the air intake valve, calculates the estimated intake channel pressure under standard atmospheric pressure using a model, and calculates a correction coefficient using the actual intake channel pressure and the estimated intake channel pressure. Then, an estimated intake valve channel air volume under standard atmospheric pressure is calculated using a model, and the intake valve channel air volume under current atmospheric pressure is calculated by way of correcting the estimated intake valve channel air volume using the correction coefficient.

Description

Intake air amount estimation device for supercharged engine

The present invention relates to an intake air amount estimation device for a supercharged engine.

A method for estimating the intake air amount of a supercharged engine using a physical model is known. According to this method, it is possible to accurately estimate the amount of intake air that varies depending on the operating state of an actuator such as a throttle or a wastegate valve.

By the way, atmospheric pressure affects the intake air volume of the engine. For example, in an environment where the atmospheric pressure is low such as a high altitude, if the operation state of the actuator is the same, the amount of intake air is smaller than that in an environment where the atmospheric pressure is high such as a low altitude. Therefore, in order to keep the estimation accuracy of the intake air amount high regardless of the environmental conditions, the influence of the atmospheric pressure on the intake air amount should be considered.

In this regard, Patent Document 1 below discloses that an atmospheric pressure measured by an atmospheric pressure sensor is used for calculation in a physical model in an apparatus that estimates the intake air amount of a supercharged engine using a physical model. ing. A similar technique is also disclosed in Patent Document 2 below. Although the technique disclosed in Patent Document 2 is directed to a naturally aspirated engine, the atmospheric pressure measured by the atmospheric pressure sensor is also used in the calculation in the physical model.

However, when the techniques disclosed in Patent Documents 1 and 2 are employed, it is essential to provide an atmospheric pressure sensor. To reduce the manufacturing cost of the entire engine, we want to reduce the number of sensors equipped on the engine as much as possible. In particular, in the case of a supercharged engine, a supercharging pressure sensor for measuring the supercharging pressure upstream of the throttle or an intake manifold pressure sensor for measuring the intake manifold pressure downstream of the throttle is already provided. There are many cases. Therefore, providing an atmospheric pressure sensor in addition to these pressure sensors is to be avoided if possible from the viewpoint of manufacturing cost.

Therefore, it is conceivable to estimate the atmospheric pressure using information obtained by an existing pressure sensor. For example, in Patent Document 3 below, based on the intake manifold pressure measured by the intake manifold pressure sensor, the throttle opening, and the flow rate of air passing through the throttle, the atmospheric pressure is calculated using a physical model that models the throttle. An estimation technique is disclosed. A similar technique is also disclosed in Patent Document 4 below.

However, the techniques disclosed in Patent Documents 3 and 4 are techniques for a naturally aspirated engine. If it is a naturally aspirated engine, the pressure upstream of the throttle is approximately equal to the atmospheric pressure. However, in the case of a supercharged engine, air is supercharged by the compressor, so the pressure upstream of the throttle does not match the atmospheric pressure. Therefore, the techniques disclosed in Patent Documents 3 and 4 cannot be applied to a supercharged engine.

JP 2009-121356 A JP 2004-197614 A JP 2008-144641 A JP 2011-144682 A

The present invention has been made in view of the above problems, and an object of the present invention is to accurately calculate an intake air amount that is influenced by atmospheric pressure without using an atmospheric pressure sensor in an intake air amount estimation device for a supercharged engine. And

The intake air amount estimation device according to the present invention measures the pressure in the intake passage by a pressure sensor arranged at a predetermined position of the intake passage from the compressor to the intake valve. As an example of such a pressure sensor, a general supercharging pressure sensor or an intake manifold pressure sensor can be cited as a supercharged engine. The supercharging pressure sensor is arranged in the intake passage from the compressor to the throttle. The intake manifold pressure sensor is disposed in the intake passage from the throttle to the intake valve.

In addition, the intake air amount estimation device according to the present invention calculates the estimated intake passage pressure under the standard atmospheric pressure using a model in parallel with measuring the actual intake passage pressure by the pressure sensor. . The model used for calculating the estimated intake passage pressure is a model that represents the relationship that holds between the operating state of the actuator, the atmospheric pressure, and the intake passage pressure at the predetermined position. The actuator in this model is an actuator that acts on the relationship between the atmospheric pressure and the pressure in the intake passage at the predetermined position, and a throttle, a waste gate valve, and the like correspond to the actuator. By inputting the operating state of the actuator and the standard atmospheric pressure into the model, the estimated intake passage pressure under the standard atmospheric pressure is calculated.

The intake air amount estimation device according to the present invention calculates the correction coefficient using the actual intake passage pressure and the estimated intake passage pressure. Preferably, the pressure ratio between the actual intake passage pressure and the estimated intake passage pressure is calculated as a correction coefficient.

Furthermore, the intake air amount estimation device according to the present invention calculates the estimated intake valve passage air amount under standard atmospheric pressure using a model. The model used for calculating the estimated intake valve passing air amount is a model that represents the relationship that holds between the operating state of the actuator, the atmospheric pressure, and the intake valve passing air amount. The actuator in this model is an actuator that affects the relationship between the atmospheric pressure and the amount of air passing through the intake valve, and the throttle timing, the wastegate valve, the valve timing variable mechanism of the intake valve and the exhaust valve, and the like correspond to the actuator. By inputting the operating state of the actuator and the standard atmospheric pressure into the model, the estimated intake valve passing air amount under the standard atmospheric pressure is calculated.

The intake air amount estimation device according to the present invention calculates the intake valve passage air amount under the current atmospheric pressure by correcting the estimated intake valve passage air amount using a correction coefficient. According to the inventors of the present application, at least when the engine is in a steady state, it is confirmed that the amount of air passing through the intake valve is proportional to the atmospheric pressure if the operation state of the related actuator is the same. . In addition, at least when the engine is in a steady state, it is confirmed that the pressure in the intake passage at a predetermined position of the intake passage from the compressor to the intake valve is proportional to the atmospheric pressure if the operation state of the related actuator is the same. ing. From these facts, multiply the estimated intake valve passage air amount under standard atmospheric pressure by the correction coefficient calculated using the actual intake passage pressure and the estimated intake passage pressure under standard atmospheric pressure. Thus, it is understood that the estimated intake valve passing air amount under the standard atmospheric pressure can be converted into the intake valve passing air amount under the current atmospheric pressure.

As described above, according to the intake air amount estimation device according to the present invention, an atmospheric pressure sensor is not required by using a pressure sensor disposed at a predetermined position in the intake passage from the compressor to the intake valve. The amount of air passing through the intake valve under the current atmospheric pressure can be calculated. The final intake air amount, that is, the amount of air remaining in the cylinder and contributing to combustion is calculated by subtracting the scavenging amount from the intake valve passing air amount.

It is a functional block diagram which shows the structure of the intake air amount estimation apparatus of the supercharged engine which concerns on Embodiment 1 of this invention. It is a functional block diagram which shows the detail of the air model which the intake air amount estimation apparatus shown in FIG. 1 uses. It is a flowchart which shows the calculation procedure of the intake valve passage air amount by the intake air amount estimation device shown in FIG. It is a functional block diagram which shows the structure of the intake air amount estimation apparatus of the supercharged engine which concerns on Embodiment 2 of this invention. FIG. 5 is a flowchart showing a calculation procedure of an intake valve passage air amount by the intake air amount estimation device shown in FIG. 4;

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described with reference to the drawings.

The supercharged engine to which the intake air amount estimation device according to the present embodiment is applied is a spark ignition type four-cycle reciprocating engine equipped with an electronically controlled throttle. The supercharger according to the present embodiment is a turbo-type supercharger that drives a compressor disposed in an intake passage by rotation of a turbine disposed in an exhaust passage. The turbocharger is provided with a waste gate valve that bypasses the turbine and an air bypass valve that bypasses the compressor. An intercooler is provided between the compressor and the throttle for cooling the air whose temperature has increased due to compression by the compressor. A supercharging pressure sensor for measuring the supercharging pressure is attached to the outlet of the intercooler in the intake passage.

The operation of the supercharged engine is controlled by an in-vehicle ECU (Electronic Control Unit) which is a computer. The ECU has various functions such as vehicle control and engine control. The intake air amount estimation device according to the present embodiment is realized as part of the function of the ECU. Specifically, when the program stored in the memory is executed by the CPU, the ECU functions as an intake air amount estimation device.

FIG. 1 is a functional block diagram showing a configuration of an intake air amount estimation device 100 realized by the ECU functioning in accordance with a program. The intake air amount estimation device 100 according to the present embodiment includes an estimated boost pressure calculation unit 102, a correction coefficient calculation unit 104, an estimated intake valve passage air amount calculation unit 106, and an actual intake valve passage air amount calculation unit 108. These calculation units are calculation units that are virtually realized by a program being executed by a CPU. However, each of these calculation units may be configured by independent hardware.

The estimated supercharging pressure calculation unit 102 is a calculation unit that calculates an estimated supercharging pressure under the standard atmospheric pressure based on the current operating state of the actuator. The estimated supercharging pressure calculation unit 102 uses an air model for calculating the estimated supercharging pressure. The air model is a dynamic model that expresses the behavior of air in the intake passage from the air cleaner to the intake valve using mathematical formulas. Details of the air model used in the present embodiment will be described later.

The correction coefficient calculation unit 104 is a calculation unit that calculates a correction coefficient using the actual boost pressure measured by the boost pressure sensor 10 and the estimated boost pressure calculated by the estimated boost pressure calculation unit 102. A pressure ratio between the actual supercharging pressure and the estimated supercharging pressure is calculated as a correction coefficient. The actual supercharging pressure measured by the supercharging pressure sensor 10 is a supercharging pressure under the current atmospheric pressure, and the estimated supercharging pressure is a supercharging pressure under the standard atmospheric pressure. From experimental data, it has been confirmed that the pressure ratio between the actual supercharging pressure and the estimated supercharging pressure is equal to the pressure ratio between the current atmospheric pressure and the standard atmospheric pressure.

The estimated intake valve passage air amount calculation unit 106 is a calculation unit that calculates an estimated intake valve passage air amount under the standard atmospheric pressure based on the current operating state of the actuator. The estimated intake valve passing air amount calculation unit 106 uses an air model for calculating the estimated intake valve passing air amount. The air model used by the estimated intake valve passing air amount calculation unit 106 is the same air model as the air model used by the estimated boost pressure calculation unit 102.

The actual intake valve passing air amount calculating unit 108 uses the estimated intake valve passing air amount calculated by the estimated intake valve passing air amount calculating unit 106 and the correction coefficient calculated by the correction coefficient calculating unit 104 to obtain the current large value. This is a calculation unit for calculating the amount of air passing through the intake valve under atmospheric pressure. The correction coefficient, which is the pressure ratio between the actual boost pressure obtained under the current boost pressure and the estimated boost pressure under the standard atmospheric pressure, is used as the estimated intake valve passing air volume under the standard atmospheric pressure. By multiplying, the intake valve passing air amount under the current atmospheric pressure is calculated. It has been confirmed from experimental data obtained by the inventors that the calculated value of the intake valve passing air amount obtained in this way matches the actual value of the intake valve passing air amount.

Next, the air model used in this embodiment will be described. FIG. 2 is a functional block diagram showing details of the air model. The air model includes a plurality of element models, that is, a wastegate valve response model M0, a turbo speed model M1, a compressor model M2, an intercooler model M3, a throttle model M4, an intake manifold model M5, an intake valve model M6, an air cleaner model M7, and an air The bypass valve model M8 is used. Hereinafter, the contents of these element models included in the air model will be described. However, these element models are publicly known, and since they are not characteristic points in the present invention, description of the details of each element model such as mathematical formulas and maps is omitted.

The waste gate valve response model M0 is a model for calculating the actual opening degree of the waste gate valve from the instruction opening degree with respect to the waste gate valve, and the response characteristic of the actual opening degree with respect to the instruction opening degree is modeled. In the waste gate valve response model M0, the current indicated opening degree inputted to the waste gate valve is inputted.

The turbo speed model M1 is a model of the rotational behavior of the supercharger, and a relationship that is established among the intake valve flow rate, the wastegate valve opening degree, and the turbo speed is modeled. In the turbo speed model M1, information such as a waste gate valve opening “wgv” calculated in the waste gate valve response model M0 and an intake valve flow rate “mc” calculated in an intake valve model M6 described later is input. The turbo speed “Ntb” is calculated from the input information.

The compressor model M2 is a turbocharger compressor model, and models the relationship that holds between the turbo speed, the supercharging pressure (compressor downstream pressure), the air cleaner downstream pressure (compressor upstream pressure), and the compressor flow rate. Has been. In the compressor model M2, the turbo speed “Ntb” calculated by the turbo speed model M1, the supercharging pressure “Pic” calculated by the intercooler model M3 described later, and the air cleaner calculated by the air cleaner model M7 described later. Information such as the downstream pressure “Pac” is input, and the compressor flow rate “mcp” is calculated from the input information.

The intercooler model M3 is a physical model constructed based on the conservation law regarding the air in the intercooler in the intake passage. As the intercooler model M3, specifically, an energy conservation law formula and a flow rate conservation law formula are used. In the intercooler model M3, a flow rate obtained by subtracting an air bypass valve flow rate “mabv” calculated in an air bypass valve model M8 described later from a compressor flow rate “mcp” calculated in the compressor model M2, and a throttle model M4 described later. Information such as the throttle flow rate “mt” is input, and the supercharging pressure “Pic” is calculated from the input information.

The throttle model M4 is a model for calculating the flow rate of air passing through the throttle. Specifically, the throttle model M4 is based on a differential pressure before and after the throttle, a flow passage area determined by the throttle opening, and a flow coefficient. The orifice flow rate formula is used. In the throttle model M4, the measured value of the throttle opening by the throttle opening sensor, the supercharging pressure “Pic” calculated by the intercooler model M3, and the intake manifold pressure “Pm” calculated by the intake manifold model M5 described later. The throttle flow rate “mt” is calculated from the input information.

The intake manifold model M5 is a physical model constructed on the basis of the conservation law regarding air in the intake manifold model. As the intake manifold model M5, specifically, an energy conservation law equation and a flow rate conservation law equation are used. In the intake manifold model M5, information such as a throttle flow rate “mt” calculated by the throttle model M4 and an intake valve flow rate “mc” calculated by an intake valve model M6 to be described later is input. The model pressure “Pm” is calculated.

The intake valve model M6 is a model based on the experimental results of examining the relationship between the intake valve flow rate and the intake manifold model pressure. Based on empirical rules obtained through experiments, in the intake valve model M6, the relationship between the intake air amount and the intake pipe pressure is approximated by a broken line (or a straight line). The coefficient of the equation of the broken line (or straight line) is not a constant, but is a variable determined by the engine speed, the wastegate valve opening, the valve timing of the intake valve, the valve timing of the exhaust valve, and the like. In the intake valve model M6, in addition to the intake manifold model pressure “Pm” calculated by the intake manifold model M5, information such as the engine speed, the wastegate valve opening, the intake valve timing, and the exhaust valve timing is input. The intake valve flow rate “mc” is calculated from the input information.

The air cleaner model M7 is a model for calculating the pressure loss generated in the air cleaner disposed at the inlet of the intake passage. The air cleaner model M7 calculates a value obtained by subtracting the pressure loss from the standard atmospheric pressure as the air cleaner downstream pressure “Pac”. The standard atmospheric pressure value is stored in the ECU memory as a default value. The pressure loss can be calculated from the flow rate of air passing through the air cleaner. In the air cleaner model M7, the flow rate obtained by subtracting the air bypass valve flow rate “mabv” from the compressor flow rate “mcp” is used as the flow rate of the air that has passed through the air cleaner.

The air bypass valve model M8 is a model for calculating the flow rate of air returned from the downstream side to the upstream side of the compressor by the air bypass valve. As the air bypass valve model M8, a throttle equation is used. In the air bypass valve model M8, information such as the air cleaner downstream pressure “Pac” calculated by the air cleaner model M7, the supercharging pressure “Pic” calculated by the intercooler model M3, and the operation flag of the air bypass valve are input. The air bypass valve flow rate “mabv” is calculated from the input information.

According to the air model configured as described above, the boost pressure realized by the current throttle opening, the current wastegate valve opening, and the current air bypass valve opening at the standard atmospheric pressure is the intercooler model M3. Is output from. The estimated supercharging pressure calculation unit 102 calculates the supercharging pressure output from the intercooler model M3 as the estimated supercharging pressure “Pic0” under the standard atmospheric pressure.

Further, according to the air model configured as described above, the intake manifold pressure realized by the current throttle opening, the current wastegate valve opening, and the current air bypass valve opening at the standard atmospheric pressure is the intake manifold pressure. Output from model M5. The estimated intake valve passage air amount calculation unit 106 calculates the intake valve passage air amount based on the intake manifold pressure output from the intake manifold model M5, and calculates the calculated intake valve passage air amount “under standard atmospheric pressure”. Calculated as KL0 ”.

Finally, the calculation procedure of the intake valve passage air amount by the intake air amount estimation device 100 according to the present embodiment is confirmed by the flowchart shown in FIG.

In step S102, the estimated supercharging pressure calculation unit 102 calculates the estimated supercharging pressure “Pic0” under the standard atmospheric pressure. Specifically, the supercharging pressure output from the intercooler model M3 in the calculation using the air model is calculated as the estimated supercharging pressure “Pic0” under the standard atmospheric pressure.

In step S104, the actual boost pressure “Pic” measured by the boost pressure sensor 10 is taken into the intake air amount estimation device 100. Note that the execution order of step S102 and step S104 may be reversed or may be executed in parallel.

In step S106, the correction coefficient calculation unit 104 calculates the pressure ratio “Pic / Pic0” between the actual supercharging pressure “Pic” and the estimated supercharging pressure “Pic0” as a correction coefficient.

In step S108, the estimated intake manifold passage air amount calculation unit 106 calculates the estimated intake manifold pressure “Pm0” under the standard atmospheric pressure. Specifically, the intake manifold pressure output from the intake manifold model M5 is calculated as the estimated intake manifold pressure “Pm0” under the standard atmospheric pressure in the calculation using the air model.

In step S110, the estimated intake valve passing air amount calculation unit 106 calculates the estimated intake valve passing air amount “KL0” under the standard atmospheric pressure from the estimated intake manifold pressure “Pm0” under the standard atmospheric pressure. . From the intake manifold pressure, the intake valve flow rate can be obtained by using the intake valve model M6, and the intake valve passing air amount is calculated by multiplying the intake valve flow rate by the valve opening time per cycle of the intake valve. Can do.

In step S112, the actual intake valve passing air amount calculation unit 108 calculates the intake valve passing air amount “KL” under the current atmospheric pressure by the following equation. As shown in this equation, the estimated intake valve passing air amount “KL0” under standard atmospheric pressure is multiplied by the pressure ratio “Pic / Pic0” between the actual boost pressure “Pic” and the estimated boost pressure “Pic0”. Thus, the estimated intake valve passing air amount “KL0” under the standard atmospheric pressure can be converted into the intake valve passing air amount “KL” under the current atmospheric pressure.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described with reference to the drawings.

The intake air amount estimation device according to the present embodiment is suitable for a supercharged engine similar to that of the first embodiment. However, the supercharged engine according to the present embodiment does not include a supercharging pressure sensor, but instead includes an intake manifold pressure sensor. The intake manifold pressure sensor is attached between the throttle and the intake valve in the intake passage. It has been.

FIG. 4 is a functional block diagram showing the configuration of the intake air amount estimation device 200 according to the present embodiment. The intake air amount estimating apparatus 200 according to the present embodiment includes an estimated intake manifold pressure calculating unit 202, a correction coefficient calculating unit 204, an estimated intake valve passing air amount calculating unit 206, and an actual intake valve passing air amount calculating unit 208. These calculation units are calculation units that are virtually realized by a program being executed by a CPU. However, each of these calculation units may be configured by independent hardware.

The estimated intake manifold pressure calculation unit 202 is a calculation unit that calculates an estimated intake manifold pressure under standard atmospheric pressure based on the current operating state of the actuator. The estimated intake manifold pressure calculating unit 202 uses an air model for calculating the estimated intake manifold pressure. The air model is a dynamic model that expresses the behavior of air in the intake passage from the air cleaner to the intake valve using mathematical formulas. The air model used in the present embodiment is the same air model shown in FIG. 2 as that used in the first embodiment. According to this air model, the intake manifold model M5 outputs the intake manifold pressure realized by the current throttle opening, the current wastegate valve opening, and the current air bypass valve opening at the standard atmospheric pressure.

The correction coefficient calculation unit 204 is a calculation unit that calculates a correction coefficient using the actual intake manifold pressure measured by the intake manifold pressure sensor 20 and the estimated intake manifold pressure calculated by the estimated intake manifold pressure calculation unit 202. In the present embodiment, the pressure ratio between the actual intake manifold pressure and the estimated intake manifold pressure is calculated as a correction coefficient. The actual intake manifold pressure measured by the intake manifold pressure sensor 20 is the intake manifold pressure under the current atmospheric pressure, and the estimated intake manifold pressure is the intake manifold pressure under the standard atmospheric pressure. From experimental data, it has been confirmed that the pressure ratio between the actual intake manifold pressure and the estimated intake manifold pressure is equal to the pressure ratio between the current atmospheric pressure and the standard atmospheric pressure.

The estimated intake valve passage air amount calculation unit 206 has the same function as the estimated intake valve passage air amount calculation unit 106 of the first embodiment. The estimated intake valve passing air amount calculation unit 206 calculates an estimated intake valve passing air amount under standard atmospheric pressure using the air model shown in FIG.

The actual intake valve passing air amount calculation unit 208 has the same function as the actual intake valve passing air amount calculation unit 208 of the first embodiment. By multiplying the estimated intake valve passing air amount by the correction coefficient calculated by the correction coefficient calculating unit 204, the intake valve passing air amount under the current atmospheric pressure is calculated. It has been confirmed from experimental data obtained by the inventors that the calculated value of the intake valve passing air amount obtained in this way matches the actual value of the intake valve passing air amount.

FIG. 5 is a flowchart showing the calculation procedure of the intake valve passing air amount by the intake air amount estimating apparatus 200 according to the present embodiment.

In step S202, the estimated intake manifold pressure “Pm0” under the standard atmospheric pressure is calculated by the estimated intake manifold pressure calculating unit 202. Specifically, in the calculation by the air model, the intake manifold pressure output from the intake manifold model M5 is calculated as the intake manifold pressure “Pm0” under the standard atmospheric pressure.

In step S204, the actual intake manifold pressure “Pm” measured by the intake manifold pressure sensor 20 is taken into the intake air amount estimation device 100. Note that the execution order of step S202 and step S204 may be reversed or executed in parallel.

In step S206, the correction coefficient calculation unit 204 calculates the pressure ratio “Pm / Pm0” between the actual intake manifold pressure “Pm” and the estimated intake manifold pressure “Pm0” as a correction coefficient.

In step S208, the estimated intake valve passing air amount calculation unit 206 calculates the estimated intake valve passing air amount “KL0” under the standard atmospheric pressure from the estimated intake manifold pressure “Pm0” under the standard atmospheric pressure. .

In step S210, the actual intake valve passing air amount calculation unit 208 calculates the intake valve passing air amount “KL” under the current atmospheric pressure by the following equation. As shown in this equation, the estimated intake valve passing air amount “KL0” under standard atmospheric pressure is multiplied by the pressure ratio “Pm / Pm0” between the actual intake manifold pressure “Pm” and the estimated intake manifold pressure “Pm0”. Thus, the estimated intake valve passing air amount “KL0” under the standard atmospheric pressure can be converted into the intake valve passing air amount “KL” under the current atmospheric pressure.

Others.
The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the first embodiment, the pressure ratio between the actual supercharging pressure and the estimated supercharging pressure is calculated and used as a correction coefficient. However, a map that associates the correction coefficient with the actual supercharging pressure and the estimated supercharging pressure is prepared. In addition, the correction coefficient may be determined from the map. The same applies to the second embodiment. A map that associates the correction coefficient with the actual intake manifold pressure and the estimated intake manifold pressure may be prepared, and the correction coefficient may be determined from the map.

Further, the model used for calculating the estimated supercharging pressure and the estimated intake manifold pressure is not limited to the one shown in FIG. The air model shown in FIG. 2 is a dynamic model in which a dynamic relationship between parameters is described. However, in the present invention, a model in which a static relationship between parameters in a steady state is described can be used.

In the supercharged engine to which the intake air amount estimation device according to the present invention is applied, an intercooler and an air bypass valve are not essential. Conversely, an EGR device may be provided in a supercharged engine to which the intake air amount estimation device according to the present invention is applied. In that case, what is necessary is just to change the structure of the air model shown in FIG. 2 according to the equipment to abbreviate | omit or the equipment to add. For example, in the case of a supercharged engine having no air bypass valve, the air bypass model may be omitted from the air model. Further, in the case of a supercharged engine having an EGR device, the EGR model may be added to the air model.

DESCRIPTION OF SYMBOLS 10 Supercharging pressure sensor 20 Intake manifold pressure sensor 100 Intake air amount estimation apparatus 102 Estimated supercharging pressure calculation unit 104 Correction coefficient calculation unit 106 Estimated intake valve passage air amount calculation unit 108 Actual intake valve passage air amount calculation unit 200 Intake air amount Estimator 202 Estimated intake manifold pressure calculating unit 204 Correction coefficient calculating unit 206 Estimated intake valve passing air amount calculating unit 208 Actual intake valve passing air amount calculating unit M0 Wastegate valve response model M1 Turbo speed model M2 Compressor model M3 Intercooler model M4 Throttle model M5 Intake manifold model M6 Intake valve model M7 Air cleaner model M8 Air bypass valve

Claims

In an intake air amount estimation device for a supercharged engine comprising a pressure sensor at a predetermined position in an intake passage from a compressor to an intake valve,
Means for acquiring an actual intake passage pressure at the predetermined position measured by the pressure sensor;
Based on the operating state of the actuator acting on the relationship between the atmospheric pressure and the pressure in the intake passage at the predetermined position, the relationship between the operating state of the actuator and the atmospheric pressure and the pressure in the intake passage at the predetermined position is expressed. Means for calculating an estimated intake passage pressure under standard atmospheric pressure at the predetermined position using a model;
Means for calculating a correction coefficient using the actual intake passage pressure and the estimated intake passage pressure;
Based on the operating state of the actuator that affects the relationship between the atmospheric pressure and the intake valve passing air amount, a model that represents the relationship between the operating state of the actuator and the atmospheric pressure and the intake valve passing air amount is used as a standard. Means for calculating an estimated intake valve passing air amount under atmospheric pressure;
Means for calculating the intake valve passage air amount under the current atmospheric pressure by correcting the estimated intake valve passage air amount using the correction coefficient;
An intake air amount estimation device for a supercharged engine comprising:
A supercharged engine intake air amount estimation device, wherein a pressure ratio between the actual intake passage internal pressure and the estimated intake passage internal pressure is calculated as the correction coefficient.
3. The intake air amount estimation device for a supercharged engine according to claim 1, wherein the pressure sensor is a supercharging pressure sensor arranged in an intake passage from a compressor to a throttle.
3. The intake air amount estimation device for a supercharged engine according to claim 1, wherein the pressure sensor is an intake manifold pressure sensor disposed in an intake passage from a throttle to an intake valve.