# US 2013/0239669 A1 · Estimation device for cylinder intake air amount in an internal combustion engine

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- Number: US 2013/0239669 A1
- Document ID: US20130239669A1
- Status: Published application
- Kind: A1
- Application number: 13/763,982
- Filed: 2013-02-11
- Published: 2013-09-19
- Earliest claimed: 2012-03-19
- Assignees: Mitsubishi Electric Corporation
- Inventors: Hideki HAGARI; Tomokazu MAKINO
- Web page: https://patentgrep.com/patent/US20130239669A1

## CPC

- G01M 15/08: by monitoring pressure in cylinders
- F02D 41/18: by measuring intake air flow
- G01F 1/00: Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow (measuring a proportion of the volume flow G01F5/00)
- G01F 15/001: {Means for regulating or setting the meter for a predetermined quantity}
- G01F 15/002: {for gases}
- F02D 2041/001: {for engines with variable valve actuation}
- F02D 2200/0402: the parameter being determined by using a model of the engine intake or its components
- F02D 2200/0406: Intake manifold pressure
- F02D 2200/0411: Volumetric efficiency
- G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W)
- G01F: MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME

## Abstract

An estimation device for a cylinder intake air amount in an internal combustion engine is obtained which can estimate an amount of air actually sucked into a cylinder with a high degree of accuracy by using a physical model of an intake system. A volumetric efficiency corresponding value is calculated based on an exhaust efficiency (a linear function of intake pipe internal pressure) which is an index indicating an amount of residual gas which is an exhaust gas after combustion remaining in the cylinder without being discharged from the interior of the cylinder to an exhaust pipe, and an intake efficiency (a linear function of intake pipe internal pressure) which is an index indicating an amount of air coming into the cylinder from an intake pipe excluding the residual gas, whereby the estimation is carried out to a high degree of accuracy with a small number of adaptation constants.

## Claims

### Claim 1

An estimation device for a cylinder intake air amount in an internal combustion engine,
which serves for estimating an amount of intake air sucked into a cylinder in the internal combustion engine (1) which is connected to an intake pipe at a location downstream of a throttle valve (4), said estimation device comprising:
a volumetric efficiency corresponding value calculation unit (22, 22A) that calculates a volumetric efficiency corresponding value (Kv) which is an index indicating an amount of air coming into said cylinder from said intake pipe; and
a cylinder intake air amount estimation unit (21, 21A) that estimates an amount of air actually sucked into said cylinder by using said volumetric efficiency corresponding value (Kv);
wherein said volumetric efficiency corresponding value calculation unit (22, 22A) calculates said volumetric efficiency corresponding value (Kv) based on an exhaust efficiency (Kex), which is an index indicating an amount of residual gas which is an exhaust gas after combustion remaining in said cylinder without being discharged into an exhaust pipe from the interior of said cylinder, and an intake efficiency (Kin), which is an index indicating an amount of air which comes into said cylinder from said intake pipe except for said amount of residual gas.

### Claim 2 (depends on 1)

The estimation device for a cylinder intake air amount in an internal combustion engine, as set forth in claim 1, further comprising:
an intake air amount detection unit (2) that is arranged at the upstream side of said throttle valve (4), and serves to detect an amount of intake air which passes through said throttle valve (4) and is sucked into said internal combustion engine (1); and
a physical model that models a response delay of the intake system until the air having passed through said throttle valve (4) comes into said cylinder;
wherein said cylinder intake air amount estimation unit (21) estimates the amount of air (Qc(n)T(n)) actually sucked into said cylinder based on said amount of intake air, said volumetric efficiency corresponding value (Kv) and said physical model.

### Claim 3 (depends on 1)

The estimation device for a cylinder intake air amount in an internal combustion engine, as set forth in claim 1, further comprising:
an intake pipe internal pressure detection unit (7) that serves to detect a pressure in said intake pipe as an intake pipe Internal pressure (Pb);
wherein said cylinder intake air amount estimation unit (21A) estimates the amount of intake air (Qc(n)T(n)) actually sucked into said cylinder based on said intake pipe internal pressure (Pb) and said volumetric efficiency corresponding value (Kv).

### Claim 4 (depends on 1)

The estimation device for a cylinder intake air amount in an internal combustion engine, as set forth in claim 1, wherein
said volumetric efficiency corresponding value calculation unit (22, 22A) calculates said volumetric efficiency corresponding value (Kv) by using the following expression (1)
[
Expression


1
]
Kv
=
K
in
·
(
ɛ
ɛ
-
1
-
K
ex
·
1
ɛ
-
1
)
,
(
1
)
based on said intake efficiency (Kin), said exhaust efficiency (Kex), and a compression ratio (ε).

### Claim 5 (depends on 4)

The estimation device for a cylinder intake air amount in an internal combustion engine, as set forth in claim 4, wherein
said intake efficiency (Kin) is calculated by using the following expression (2),
[
Expression


2
]
K
in
=
P
in
P
b
·
T
b
T
in
,
(
2
)
based on a cylinder internal pressure (Pin [kPa]) and an intake pipe internal pressure (Pb [kPa]) at the time of the end of an intake stroke, as well as a cylinder internal temperature (Tin [degrees K]) and an intake pipe internal temperature (Tb [degrees K]) at the time of the end of the intake stroke.

### Claim 6 (depends on 5)

The estimation device for a cylinder intake air amount in an internal combustion engine, as set forth in claim 5, wherein
a pressure ratio (Pin/Pb) between said cylinder internal pressure (Pin) and said intake pipe internal pressure (Pb) at the time of the end of said intake stroke, which is used for calculation of said intake efficiency (Kin), is approximated as a linear function of said intake pipe internal pressure (Pb).

### Claim 7 (depends on 4)

The estimation device for a cylinder intake air amount in an internal combustion engine, as set forth in claim 4, wherein
said exhaust efficiency (Kex) is calculated by using the following expression (3),
[
Expression


3
]
K
ex
=
V
ex
V
min
·
P
ex
P
in
·
T
in
T
ex
,
(
3
)
based on a cylinder clearance volume (a volume of a combustion chamber in said cylinder at the time of top dead center) (Vmin [cc]), a residual gas volume (Vex [cc]), a cylinder internal pressure (Pin [kPa]) and an exhaust pipe internal pressure (Pex [kPa]) at the time of the end of an intake stroke, as well as a cylinder internal temperature (Tin [degrees K]) and an exhaust temperature (Tex [degrees K]) at the time of the end of the intake stroke.

### Claim 8 (depends on 7)

The estimation device for a cylinder intake air amount in an internal combustion engine, as set forth in claim 7, wherein
said exhaust efficiency (Kex) is approximated as a linear function of said intake pipe internal pressure (Pb).

### Claim 9 (depends on 5)

The estimation device for a cylinder intake air amount in an internal combustion engine, as set forth in claim 5, wherein
a maximum value of the intake pipe internal pressure between prescribed crank angles of said internal combustion engine (1) is used as said intake pipe internal pressure.