Turbine expansion ratio estimation for model-based boost control

Patent metadata

Field	Value
Publication number	US-9822697-B2
Application number	US-201414294559-A
Country	US
Kind code	B2
Filing date	Jun 3, 2014
Priority date	Jun 3, 2014
Publication date	Nov 21, 2017
Grant date	Nov 21, 2017

Abstract

A method for controlling a turbine of an engine system to achieve a desired boost pressure is provided. The method determines a desired exhaust gas pressure based on the desired boost pressure by using a model for a power balance between the turbine and a compressor of the engine system. The method generates a base command for controlling a position of a vane of the turbine based on a ratio of the desired exhaust gas pressure to a measured turbine outlet pressure.

First claim

What is claimed is:

1. A method for controlling a turbine of an engine system to achieve a commanded boost pressure, the method comprising:
determining, in a control module, an exhaust gas pressure based on the commanded boost pressure by using a model for a power balance between the turbine and a compressor of the engine system using an equation

p

ex
,
dsr

=

p
to

⁢

f
⁡

(

m
.

ex

⁢

T
ex

p
to

,

P

c
,
dsr

h
t

)

,

wherein where p ex,dsr is exhaust gas pressure; p to is a measured turbine outlet pressure, {dot over (m)} ex is an estimated exhaust gas flow rate, T ex is an estimated temperature of the exhaust gas, p to is a measured turbine outlet pressure, P c,dsr is a power to be generated by the compressor, and h t is an exhaust gas enthalpy flow;
generating, at the control module, a base command for controlling a position of a vane of the turbine to a threshold ratio of the exhaust gas pressure to a measured turbine outlet pressure;
sending a vane position command from the control module to the turbine of the engine system; and
adjusting the vane position of the turbine.

2. The method of claim 1 , further comprising:
generating a compensation command based on a difference between the commanded boost pressure and a measured boost pressure;
generating a final command based on the base command and the compensation command; and
sending the final command to the turbine to control the turbine.

3. The method of claim 1 , wherein the turbine is a variable geometry turbine (VGT).

4. The method of claim 1 , wherein the generating the base command comprises using a function

f
(

p
ex

p
to

,

m
.

ex

p
ex

RT
ex

·

f
1

⁡

(

p
ex

p
to

)

)

,

wherein p ex is an estimated exhaust gas pressure, p to is a measured turbine outlet pressure, p ex /p to is a turbine expansion ratio, {dot over (m)} ex is an exhaust gas flow rate, T ex is an estimated exhaust gas temperature, and R is ideal gas constant.

5. The method of claim 1 , further comprising mapping the ratio of the exhaust gas pressure to the measured turbine outlet pressure to a look up table for estimated turbine expansion ratio values indexed by different velocity values of an engine of the engine system and different desired compressor pressure ratio values.

6. The method of claim 1 , further comprising mapping the ratio of the exhaust gas pressure to the measured turbine outlet pressure to a look up table for estimated turbine expansion ratio values indexed by different velocity values of an engine of the engine system and different fuel consumption rate values of the engine.

7. An engine system comprising:
an engine;
a turbine driven by exhaust gas from the engine;
a compressor driven by the turbine; and
a control module for controlling the turbine to achieve a commanded boost pressure, the control module comprising a processor coupled to a memory, the control module configured to:
determine an exhaust gas pressure based on the commanded boost pressure by using a model for a power balance between the turbine and a compressor of the engine system using an equation

p

ex
,
dsr

=

p
to

⁢

f
⁡

(

m
.

ex

⁢

T
ex

p
to

,

Assignees

• Gm Global Tech Operations Llc

Inventors

• Ge Ping
• Wang Yue-Yun

Classifications

• Y02T10/12

  Improving ICE efficiencies · CPC title

• F02B37/24 Primary

  by using pumps or turbines with adjustable guide vanes · CPC title

• F02D41/1447

  with determination means using an estimation · CPC title

• F02D41/0007

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

• F02B37/12

  Control of the pumps · CPC title