Method of determining a pressure upstream of a compressor for an engine equipped with double supercharging

Patent metadata

Field	Value
Publication number	US-9739281-B2
Application number	US-201314427450-A
Country	US
Kind code	B2
Filing date	Aug 12, 2013
Priority date	Sep 11, 2012
Publication date	Aug 22, 2017
Grant date	Aug 22, 2017

Abstract

The invention relates to a method for determining the pressure P avcm upstream of a mechanical compressor ( 3 ) equipped with a double supercharging circuit of a combustion engine. The pressure P avcm is determined by a dynamic model based on a law of conservation of flow rate in the volume upstream of the mechanical compressor. The model links the pressure P avcm upstream of the mechanical compressor ( 3 ) to a temperature T avcm upstream of the mechanical compressor ( 3 ), to a boost pressure P sural and boost temperature T sural on the intake side of the engine, and to an openness Bypass of the bypass valve ( 4 ).

First claim

The invention claimed is:

1. A method of determining a pressure of a gaseous mixture including fresh air and burnt gas at an intake side of an internal combustion engine upstream of a mechanical compressor, at least one sensor, and a bypass circuit disposed in parallel with the mechanical compressor within a supercharging system of the internal combustion engine which includes a variable geometry turbocharger for compressing the gaseous mixture at the intake side of the engine, comprising:
a) determining a temperature of the gaseous mixture upstream of the mechanical compressor;
b) acquiring a boost pressure and a boost temperature on the intake side of the engine and a degree of opening of the bypass valve by a control unit positioned upstream of an intake manifold of the engine by the at least one sensor;
c) determining the pressure upstream of the mechanical compressor from a dynamic model programmed in a processor which executes programming expressing a conservation-of-flow law involving the gaseous mixture upstream of the mechanical compressor by determining pressure of the gaseous mixture upstream from the mechanical compressor from a temperature of the gaseous mixture upstream from the mechanical compressor and a boost pressure and a boost temperature of the gaseous mixture downstream from the mechanical compressor and a degree of opening of the bypass valve; and
d) controlling with an actuator at least the variable geometry of the turbocharger and the degree of opening of the bypass valve based upon the determined pressure of the gaseous mixture upstream of the mechanical compressor.

2. The method according to claim 1 , wherein the supercharging system comprises an air cooler for cooling a charge which is disposed between the turbocharger and the mechanical compressor and further comprising determining a temperature of the gaseous mixture upstream of the mechanical compressor by using a map of a flow rate passing through the air cooler.

3. The method according to claim 2 wherein the dynamic model is programmed in a processor which executes programming expressing a formula:

P
.

avcm

=

RT
avcm

V
avcm

⁢

(

D
bp

+

D
c

-

D
cm

)

wherein {dot over (P)} avcm is a first derivative with respect to time of pressure P avcm upstream of the mechanical compressor, R is a perfect gas constant, V avcm is a volume upstream of the mechanical compressor, D bp is a flow rate passing through the bypass valve, D c is a flow rate passing through the turbocharger and D cm is a flow rate passing through the mechanical compressor and wherein the flows D bp and D cm are dependent on the pressure P avcm upstream of the mechanical compressor, on the pressure P sural and on a boost temperature T sural on the intake side of the engine and on a degree of opening of the bypass valve.

4. The method according to claim 3 wherein:
determining a flow rate D bp passing through the bypass valve from a pressure drop relationship across the bypass valve programmed in a processor which executes programming, expressing a relationship: D bp =A bp (Bypass)×f(P avcm ,P sural ,T avcm ) where A bp (Bypass) is an area of opening of the bypass valve and f is a flow rate per unit area defined by a formula:

f
⁡

(

P
avcm

,

P
sural

,

T
avcm

)

=

P
sural

RT
avcm

⁢

{

(

P
avcm

P
sural

)

1
γ

⁢

2

γ
-
1

⁢

(

1
-

(

P
avcm

P
sural

)

γ
-
1

γ

)

if
⁢

Assignees

• Ifp Energies Now

Inventors

• Leroy Thomas
• Chauvin Jonathan
• Chasse Alexandre

Classifications

• F02B37/04 Primary

  Engines with exhaust drive and other drive of pumps, e.g. with exhaust-driven pump and mechanically-driven second pump · CPC title

• F04D27/009

  by bleeding, by passing or recycling fluid · CPC title

• F04D25/06

  the pump being electrically driven (F04D25/08 takes precedence) · CPC title

• F02M35/1038

  for temperature or pressure · CPC title

• F02D2200/0402

  the parameter being determined by using a model of the engine intake or its components · CPC title