# US 12,215,642 B2 · Compression ignition engine control

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- Number: US 12,215,642 B2
- Document ID: US12215642B2
- Status: Granted
- Kind: B2
- Application number: 18/465,387
- Filed: 2023-09-12
- Published: 2024-03-21
- Granted: 2025-02-04
- Earliest claimed: 2022-09-12
- Assignees: Regents of the University of Minnesota
- Applicants: Regents of the University of Minnesota
- Inventors: Rajesh Rajamani; Woongsun Jeon
- Web page: https://patentgrep.com/patent/US12215642B2

## CPC

- F02D 35/023: {by determining the cylinder pressure}
- F02D 35/024: {using an estimation}
- F02D 35/027: {using knock sensors}
- F02D 41/009: {using means for generating position or synchronisation signals}
- F02D 41/062: {for starting (F02D41/061 takes precedence)}
- F02D 2041/1433: {using a model or simulation of the system}
- F05D 2270/334: Vibration measurements
- 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)
- F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS

## Abstract

A method of estimating in-cylinder pressure includes receiving a vibration signal from a vibration sensor mounted proximate a compression ignition (CI) engine, receiving angular position information for the CI engine, and determining in-cylinder pressure based on the angular position information and on a combustion component of the vibration signal.

## Claims

### Claim 1

An engine system, comprising:
an engine controller;
a compression ignition (CI) engine connected to the engine controller, the CI engine configured to receive engine control signals from the engine controller and to transmit current engine operating condition measurements to the engine controller, the CI engine having an engine block, the current engine operating condition measurements including angular position information; and
a vibration sensor placed proximate to the engine block,
wherein the engine controller comprises at least one processor configured to:
receive a vibration signal from the vibration sensor;
determine a non-combustion component of the vibration signal indicative of vibrations in the engine block not caused by combustion;
determine a combustion component of the vibration signal based on the non-combustion component of the vibration signal and the vibration signal, wherein the combustion component of the vibration signal is indicative of vibrations in the engine block caused by combustion;
determine an in-cylinder pressure based on the angular position information for a current cycle of the CI engine and on the combustion component of the vibration signal; and
generate revised engine control signals for a next cycle of the CI engine based on the determined in-cylinder pressure.

### Claim 2 (depends on 1)

The system of claim 1, wherein the vibration sensor is one of an accelerometer sensor or an acoustic emission sensor.

### Claim 3 (depends on 1)

The system of claim 1, wherein the at least one processor is further configured to:
determine the non-combustion component of the vibration signal using a feedforward adaptive LMS algorithm that uses crankshaft encoder signals as a reference input to extract crankshaft-position-correlated components from the vibration signal; and
determine the combustion component of the vibration signal by subtracting the non-combustion component of the vibration signal from the vibration signal.

### Claim 4 (depends on 1)

The system of claim 1, wherein to determine the in-cylinder pressure, the at least one processor is further configured to apply a differential model of in-cylinder pressure as a function of the angular position information and of the combustion component of the vibration signal, wherein the differential model is based on a root mean squared (RMS) model of the combustion component of the vibration signal.

### Claim 5 (depends on 1)

The system of claim 1,
wherein the CI engine comprises one or more cylinders,
wherein the at least one processor is further configured to determine one or more of a start of combustion (SOC) value, a CA50 value, and a CA90 value based on the determined in-cylinder pressure and a volume of the one or more cylinders, and
wherein to determine one or more of the CA50 value, the SOC value, and the CA90 value, the at least one processor is configured to determine the crank angle at which a threshold amount of heat release has occurred based on a normalized integration of a heat release rate equation.