Power-based turbocharger boost control techniques

Patent metadata

Field	Value
Publication number	US-10584630-B2
Application number	US-201715586806-A
Country	US
Kind code	B2
Filing date	May 4, 2017
Priority date	Jun 6, 2016
Publication date	Mar 10, 2020
Grant date	Mar 10, 2020

Abstract

A power-based control system and method for an engine comprising a turbocharger involve obtaining a set of parameters that each affect exhaust gas energy and using the set of parameters to (i) determine a target mass flow into the engine and a target boost for the turbocharger to achieve a torque request, (ii) determine a target power for a compressor of the turbocharger to achieve the target engine mass flow and the target turbocharger boost, (iii) determine a target pressure ratio and a target mass exhaust flow for the turbine of the turbocharger to achieve a target turbine power equal to the target compressor power, and (iv) determine a target position of the wastegate valve to achieve the target turbine pressure ratio and mass exhaust flow, and commanding a wastegate valve to the target position.

First claim

What is claimed is:

1. A control system for an engine comprising a turbocharger, the system comprising:
a wastegate valve configured to variably open and close to control a pressure of an exhaust gas in an exhaust system of the engine at a turbine of the turbocharger; and
a controller configured to:
obtain, from a set of one or more sensors, a set of parameters;
using the set of parameters, determine a target position of the wastegate valve by performing the following steps:
(i) determine a target engine mass flow into the engine and a target turbocharger boost for the turbocharger to achieve a torque request;
(ii) determine a target power for a compressor of the turbocharger to achieve the target engine mass flow and the target turbocharger boost;
(iii) derive a turbine model based on a turbine power model, the turbine power model based on at least one of a target turbine mass exhaust flow, an exhaust gas specific heat, an exhaust gas specific heat ratio, a turbine efficiency, a turbine inlet temperature, and a turbine pressure ratio of the turbine, wherein the derived turbine model includes a turbine pressure ratio calibration map that is a function of a corrected turbine power and a corrected turbine speed;
(iv) determine a target turbine pressure ratio using the turbine pressure ratio calibration map of the derived turbine model and a target turbine power equal to the target compressor power;
(v) determine a target mass exhaust flow using a turbine flow map and the target turbine pressure ratio, wherein the turbine flow map is a function of the target turbine pressure ratio and the corrected turbine speed; and
(vi) determine the target position of the wastegate valve to achieve the target turbine pressure ratio and the target mass exhaust flow; and

command the wastegate valve to the target position.

2. The system of claim 1 , wherein the controller is configured to utilize a complete model of the turbocharger to determine the target compressor power, the target turbine pressure ratio and the target mass exhaust flow for the turbine, and the target position of the wastegate valve.

3. The system of claim 2 , wherein the controller is configured to determine the target compressor power using a compressor power model portion of the complete turbocharger model, the compressor power model utilizing the following equation:

P
C

=

m
.

⁢

⁢

c
p

⁢

T

1
⁢

⁢
C

η
C

⁢

(

PR

(

γ
-
1

γ

)

-
1

)

,

where P C is the target compressor power, {dot over (m)} is a target compressor mass flow, c p and γ are a specific heat and a specific heat ratio of intake air, respectively, T 1C is a compressor inlet temperature, PR is a compressor pressure ratio, which represents a ratio between compressor outlet pressure and compressor inlet pressure, and η C represents compressor efficiency.

4. The system of claim 3 , wherein the controller is configured to determine the target turbine pressure ratio and mass exhaust flow using the derived turbine model, which is a portion of the complete turbocharger model, the derived turbine model being derived from the following equation:

P
T

=

m
.

⁢

⁢

η
T

⁢

c
p

⁢

T

1
⁢
T

(

1
-

PR

(

γ
-
1

γ

)

)

,

where P T is the target turbine power, {dot over (m)} is the target turbine mass exhaust flow, c p and γ are the specific heat and the specific heat ratio of the exhaust gas, respectively, η T represents the turbine efficiency, T 1T is the turbine inlet temperature, and PR represents the turbine pressure ratio, which represents a ratio between turbine outlet and inlet pressures.

5. The system of claim 4 , wherein the controller is further configured to:
determine an orifice flow area for the wastegate valve to achieve the target turbine pressure ratio and the target turbine mass exhaust flow; and
determine the target position of the wastegate valve to achieve the determined orifice flow area.

6. The system of claim 5 , wherein the wastegate valve is an electrically-actuated wastegate valve that comprises an electric actuator configured to variably open and close the wastegate valve.

7. The system of claim 5 , wherein the controller is configured to determine the orifice flow area using a wastegate model portion of the complete turbocharger model, the wastegate model utilizing the following equation:

CdA
=

m
.

ρ
⁢

Assignees

• Lawrence David A
• Bayer Ethan
• Bucknell John
• Fca Us Llc

Inventors

• Lawrence David A
• Bayer Ethan
• Bucknell John

Classifications

• F02D23/00

  Controlling engines characterised by their being supercharged · CPC title

• F02D41/0007

  for control of turbo-charged or super-charged engines (control of the pumps per se F02B37/12) · CPC title

• F02B37/162

  by bypassing, e.g. partially, intake air from pump inlet to pump outlet · CPC title

• F02B37/183 Primary

  Arrangements of bypass valves or actuators therefor · CPC title

• F02B2037/122

  Control of rotational speed of the pump · CPC title