# US 2014/0196704 A1 · Turbocharger boost control using exhaust pressure estimated from engine cylinder pressure

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- Number: US 2014/0196704 A1
- Document ID: US20140196704A1
- Status: Published application
- Kind: A1
- Application number: 14/009,357
- Filed: 2012-04-19
- Published: 2014-07-17
- Earliest claimed: 2011-04-22
- Assignees: BorgWarner Inc.
- Inventors: John Shutty; Wolfgang Wenzel
- Web page: https://patentgrep.com/patent/US20140196704A1

## CPC

- F02D 41/0007: {for control of turbo-charged or super-charged engines (control of the pumps per se F02B37/12)}
- F02B 37/18: by bypassing exhaust {from the inlet to the outlet of turbine or to the atmosphere}
- F02D 35/023: {by determining the cylinder pressure}
- F02D 41/145: {with determination means using an estimation}
- F02D 2041/141: {using a feed-forward control element}
- F02D 2041/1419: {the control loops being cascaded, i.e. being placed in series or nested}
- F02D 2200/0406: Intake manifold pressure
- F02M 26/05: High pressure loops, i.e. wherein recirculated exhaust gas is taken out from the exhaust system upstream of the turbine and reintroduced into the intake system downstream of the compressor
- F02M 26/25: with coolers having bypasses
- Y02T 10/12: Improving ICE efficiencies
- 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)
- F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G)
- F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

Controlling turbocharger boost pressure using exhaust pressure estimated from engine cylinder pressure.

## Claims

### Claim 1

A method comprising:
sensing pressure within an engine cylinder;
estimating exhaust pressure based on the sensed pressure within the engine cylinder; and
controlling turbocharger boost pressure based on the estimated exhaust pressure.

### Claim 2 (depends on 1)

A method as set forth in claim 1, wherein the exhaust pressure is formulaically estimated using the following equation:
Pexhaust=f(Pcyl—max, Pcyl(θ), ν)
where:
Pexhaust=exhaust manifold pressure;
Pcyl=cylinder pressure before combustion, after compression;
Pcyl—max=maximum cylinder pressure over the current combustion cycle;
θ=exhaust valve opening angle;
Pcyl(θ)=cylinder pressure when the engine is in the position where the exhaust valves are open; and
ν=engine revolutions per minute.

### Claim 3 (depends on 1)

The method of claim 1, wherein the estimated exhaust pressure is exhaust pressure at a turbocharger turbine inlet.

### Claim 4

A method comprising:
determining a boost pressure deviation between a boost pressure setpoint and an actual boost pressure;
producing an exhaust pressure setpoint in response to the boost pressure deviation;
determining an exhaust pressure deviation between the exhaust pressure setpoint and an exhaust pressure estimate that is estimated from actual cylinder pressure; and
producing a turbocharger command in response to the exhaust pressure deviation.

### Claim 5 (depends on 4)

A method as set forth in claim 4, further comprising:
sensing cylinder pressure in an engine combustion chamber to provide the actual cylinder pressure; and
sensing turbocharger boost pressure to provide the actual boost pressure.

### Claim 6 (depends on 5)

A method as set forth in claim 5, wherein the step of producing an exhaust pressure setpoint includes using an exhaust pressure closed-loop controller, and the step of producing a turbocharger command includes using a boost pressure closed-loop controller.

### Claim 7

A method comprising:
determining a boost pressure deviation between a boost pressure setpoint and an actual boost pressure;
producing a closed-loop exhaust pressure setpoint adjustment in response to the boost pressure deviation;
producing an open-loop exhaust pressure setpoint from inputs of the boost pressure setpoint and an exhaust gas recirculation parameter;
combining the closed-loop exhaust pressure setpoint adjustment with the open-loop exhaust pressure setpoint to produce an exhaust pressure setpoint;
determining an exhaust pressure deviation between the exhaust pressure setpoint and an exhaust pressure estimate that is estimated from actual cylinder pressure;
producing a closed-loop turbocharger command adjustment in response to the exhaust pressure deviation;
producing an open-loop turbocharger command from an input of the exhaust pressure setpoint; and
combining the closed-loop turbocharger adjustment with the open-loop turbocharger command to produce the turbocharger command.

### Claim 8 (depends on 7)

A method as set forth in claim 7, further comprising:
sensing cylinder pressure in an engine combustion chamber to provide the actual cylinder pressure; and
sensing turbocharger boost pressure to provide the actual boost pressure.

### Claim 9 (depends on 1)

A method as set forth in claim 1 further comprising using a computer program to implement the method.

### Claim 10 (depends on 1)

A product, comprising:
at least one engine cylinder pressure sensor to measure engine cylinder pressure;
at least one turbocharger boost pressure sensor to measure turbocharger boost pressure;
at least one memory device storing program instructions and data;
at least one control system coupled to the sensors and memory and responsive to the program instructions for causing the computer-controlled system to perform a method according to claim 1.

### Claim 11 (depends on 10)

The product of claim 10, wherein the at least one control system includes a boost pressure closed-loop controller, and an exhaust pressure closed-loop controller.

### Claim 12 (depends on 11)

The product of claim 11, wherein the at least one control system is a dual control system also including a boost pressure open-loop controller, and an exhaust pressure open-loop controller.