# US 2017/0284897 A1 · Control system having piston rim damage counting

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- Number: US 2017/0284897 A1
- Document ID: US20170284897A1
- Status: Published application
- Kind: A1
- Application number: 15/087,439
- Filed: 2016-03-31
- Published: 2017-10-05
- Earliest claimed: 2016-03-31
- Assignees: Caterpillar Inc.
- Applicants: Caterpillar Inc.
- Inventors: Austin Paul ROE; Anthony T. PETROU; Matthew ROWAN; Timothy Edward McGREEVY
- Web page: https://patentgrep.com/patent/US20170284897A1

## CPC

- G01M 15/05: by combined monitoring of two or more different engine parameters
- F02B 77/085: {with sensors measuring combustion processes, e.g. knocking, pressure, ionization, combustion flame}
- F02D 35/023: {by determining the cylinder pressure}
- F02D 35/025: {by determining temperatures inside the cylinder, e.g. combustion temperatures}
- G01M 15/08: by monitoring pressure in cylinders
- G05B 17/00: Systems involving the use of models or simulators of said systems (G05B13/00, G05B15/00, G05B19/00 take precedence)
- G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G)
- 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)
- G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G)

## Abstract

An imbedded control system is disclosed for use with an engine having a combustion chamber and an associated piston associated. The control system may have at least one sensor configured to generate a signal indicative of a combustion process occurring inside the combustion chamber, and a controller in communication with the at least one sensor. The controller may be configured to determine an amount of heat and a pressure generated inside the combustion chamber based on the signal and a combustion model, to determine a heat flux through the piston based on the amount of heat and a heat flux model, and to determine a temperature at a rim of the piston based on the heat flux and a thermal model. The controller may be further configured to track a time at the temperature and the pressure, and to determine a damage count of the piston based on the time.

## Claims

### Claim 1

A control system imbedded within an engine having at least one combustion chamber and a piston associated with the at least one combustion chamber, the control system comprising:
at least one sensor configured to generate a signal indicative of a combustion process occurring inside the at least one combustion chamber; and
a controller in communication with the at least one sensor and configured to:
determine an amount of heat and a pressure generated inside the at least one combustion chamber based on the signal and a combustion model of the engine;
determine a heat flux through the piston based on the amount of heat and a heat flux model of the piston;
determine a temperature at a rim of the piston based on the heat flux and a thermal model of the piston;
track a time at the temperature and the pressure; and
determine a damage count of the piston based on the time at the temperature and pressure.

### Claim 2 (depends on 1)

The control system of claim 1, wherein the signal is indicative of at least one of a speed of the engine, a quantity of fuel being injected into the at least one combustion chamber, a timing of the fuel being injected, a pressure of the fuel being injected, a flow rate of air entering the at least one combustion chamber, a temperature of the air, and a pressure of the air.

### Claim 3 (depends on 1)

The control system of claim 1, wherein the controller is configured to determine the damage count in real time.

### Claim 4 (depends on 3)

The control system of claim 3, wherein the controller is configured to determine the damage count at a frequency of about 1 Hz.

### Claim 5 (depends on 1)

The control system of claim 1, wherein the controller is configured to determine the damage count based on a damage model of the piston.

### Claim 6 (depends on 5)

The control system of claim 5, wherein the damage model accounts for damage influenced by oxidation, creep, and fatigue.

### Claim 7 (depends on 1)

The control system of claim 1, wherein the controller is further configured to selectively implement a corrective action based on the damage count and a design limit of the piston.

### Claim 8 (depends on 7)

The control system of claim 7, wherein the controller is configured to generate a notice when the damage count exceeds a first percent of the design limit.

### Claim 9 (depends on 8)

The control system of claim 8, wherein the controller is further configured to recommend servicing of the piston when the damage count exceeds a second percent of the design limit that is greater than the first percent.

### Claim 10 (depends on 9)

The control system of claim 9, wherein the controller is further configured to automatically schedule servicing of the piston when the damage count exceeds a third percent of the design limit that is greater than the second percent.

### Claim 11 (depends on 1)

The control system of claim 1, wherein the thermal model represents heat flow radially outward from a center of the at least one combustion chamber.

### Claim 12 (depends on 1)

The control system of claim 1, wherein:
the signal is a first signal;
the control system further includes a coolant sensor configured to generate a coolant signal indicative of a temperature of coolant circulated through the piston; and
the controller is configured to determine the temperature at the rim of the piston based further on the coolant signal.

### Claim 13 (depends on 12)

The control system of claim 12, wherein the controller is configured to determine the heat flux through the engine based further on known material and geometry data of the piston and the coolant.

### Claim 14 (depends on 1)

The control system of claim 1, wherein the controller is configured to determine the amount of heat generated inside the at least one combustion chamber based further on a known compression ratio of the engine, a known bore diameter of the at least one combustion chamber, a known stroke length of the piston, and an assumed mixing of fuel and air occurring inside the at least one combustion chamber.

### Claim 15 (depends on 1)

The control system of claim 1, wherein the controller is configured to:
determine an average heat flux through the engine during a 720° crank-angle period of operation of the engine;
determine the temperature at the rim of the piston based on the average heat flux; and
determine the heat flux through the piston based on a known position of the piston during the 720° crank-angle period of operation of the engine.

### Claim 16 (depends on 1)

The control system of claim 1, wherein the controller is further configured to determine a current status of the piston based on the damage count and a design limit.

### Claim 17

A method of monitoring an engine by an imbedded control system, the method comprising:
sensing at least one parameter of a combustion process occurring inside at least one combustion chamber of the engine;
determining an amount of heat and a pressure generated inside the at least one combustion chamber based on the at least one parameter, a known compression ratio of the engine, a known bore diameter of the at least one combustion chamber, a known stroke length of an associated piston, an assumed mixing of fuel and air occurring inside the at least one combustion chamber, and a combustion model of the engine;
determining a heat flux through the piston based on the amount of heat, known material and geometry data of the piston, and a heat flux model of the engine;
determining a temperature of coolant circulating through the piston;
determining a temperature at a rim of the piston based on the heat flux, a thermal model of the piston, and the temperature of the coolant;
tracking a time at the temperature and the pressure; and
determining in real-time a damage count of the piston based on the time at the temperature and pressure and based on a damage model of the piston.

### Claim 18 (depends on 17)

The method of claim 17, wherein the at least one parameter is at least one of a speed of the engine, a quantity of fuel being injected into the at least one combustion chamber, a timing of the fuel being injected, a pressure of the fuel being injected, a flow rate of air entering the at least one combustion chamber, a temperature of the air, and a pressure of the air.

### Claim 19 (depends on 17)

The method of claim 17, wherein:
determining the heat flux through the piston includes determining an average heat flux through the piston during a 720° crank-angle period of operation of the engine; and
determining the temperature at the rim of the piston includes determining the temperature at the rim of the piston based on the average heat flux and a known position of the piston during the 720° crank-angle period of operation of the engine.

### Claim 20 (depends on 17)

The method of claim 17, further including determining a current status of the piston based on the damage count and a design limit.