Systems and methods of using a fuel injector as a pressure sensor to detect top-dead-center for a cylinder

Patent metadata

Field	Value
Publication number	US-12454925-B2
Application number	US-202318495690-A
Country	US
Kind code	B2
Filing date	Oct 26, 2023
Priority date	May 3, 2021
Publication date	Oct 28, 2025
Grant date	Oct 28, 2025

Abstract

A pressure-based piston top-dead-center (“TDC”) position measurement system is disclosed, comprising: a fuel injector configured to inject fuel into a combustion chamber bounded in part by the piston; and a controller configured to control the fuel injector to cause a fuel injection when the piston is at each of a plurality of different positions relative to TDC while ensuring fuel is provided to the fuel injector at a substantially constant pressure. The controller is further configured to estimate a pressure in the combustion chamber in response to each fuel injection, fit a curve to the estimated pressures, and determine a TDC position of the piston as correlating with a maximum pressure on the curve.

First claim

What is claimed is:

1. A system for determining a top-dead-center (“TDC”) position of a piston configured to reciprocate in an engine cylinder, comprising:
a fuel injector fluidically coupled to a fuel accumulator and configured to inject fuel from the fuel accumulator into the engine cylinder;
a pressure sensor positioned to sense pressure of fuel in the fuel accumulator; and
a controller in communication with the fuel injector and the pressure sensor, the controller being programmed to receive signals from the pressure sensor indicating the sensed pressure of fuel in the fuel accumulator,
prevent fuel flow into the fuel accumulator when the sensed pressure of fuel corresponds to a desired fuel pressure,
after fuel flow into the fuel accumulator is prevented, cause the fuel injector to provide a plurality of fuel injections into the engine cylinder when the piston is in a corresponding plurality of positions in the engine cylinder,
estimate a corresponding plurality of cylinder pressures in response to the plurality of fuel injections,
fit a curve to the corresponding plurality of cylinder pressures that have been estimated,
determine a maximum cylinder pressure value on the curve, and
correlate the maximum cylinder pressure value to a true TDC position of the piston.

2. The system of claim 1 , wherein the controller prevents fuel flow into the fuel accumulator by at least one of cutting off operation of a fuel pump or closing an inlet metering valve.

3. The system of claim 1 , wherein each of the plurality of fuel injections is for a fixed period of time.

4. The system of claim 1 , wherein the controller is programmed to estimate a cylinder pressure by calculating a fuel flow through the fuel injector and estimating the cylinder pressure using the calculated fuel flow.

5. The system of claim 1 , wherein the plurality of fuel injections include a first fuel injection when the piston is in a first position in the engine cylinder, a second fuel injection when the piston is in a second position in the engine cylinder, and a third fuel injection when the piston is in a third position in the engine cylinder.

6. The system of claim 1 , wherein the system determines the TDC position of the piston during an engine maintenance event.

7. The system of claim 6 , wherein the controller is programmed to cause the fuel injector to provide the plurality of fuel injections into the engine cylinder during a non-ballistic region of a curve corresponding to the fuel injector.

8. A method of using a fuel injector to determine a top-dead-center (“TDC”) position of a piston configured to reciprocate in an engine cylinder, comprising:
receiving signals from a pressure sensor indicating a sensed pressure of fuel in a fuel accumulator fluidically coupled to the fuel injector;
responding to the sensed pressure of fuel corresponding to a desired fuel pressure, preventing fuel flow into the fuel accumulator;
after preventing fuel flow into the fuel accumulator, causing the fuel injector to provide a plurality of fuel injections into the engine cylinder when the piston is in a corresponding plurality of positions in the engine cylinder;
estimating a corresponding plurality of cylinder pressures in response to the plurality of fuel injections;
estimating a plurality of accumulator fuel pressure drop measurements for injections corresponding to the corresponding plurality of cylinder pressures;
fitting a curve to the plurality of accumulator fuel pressure drop measurements that have been estimated;
determining a maximum pressure drop value on the curve; and
correlating the maximum pressure drop value to a true TDC position of the piston.

9. The method of claim 8 , wherein preventing fuel flow into the fuel accumulator includes at least one of cutting off operation of a fuel pump or closing an inlet metering valve.

10. The method of claim 8 , wherein each of the plurality of fuel injections is for a fixed period of time.

11. The method of claim 8 , wherein estimating a corresponding plurality of cylinder pressures includes calculating fuel flows through the fuel injector and estimating the cylinder pressures using the calculated fuel flows.

12. The method of claim 8 , wherein the plurality of fuel injections include a first fuel injection when the piston is in a first position in the engine cylinder, a second fuel injection when the piston is in a second position in the engine cylinder, and a third fuel injection when the piston is in a third position in the engine cylinder.

13. The method of claim 8 , wherein the method is performed during an engine maintenance event.

14. The method of claim 8 , wherein causing the fuel injector to provide a plurality of fuel injections into the engine cylinder when the piston is in a corresponding plurality of positions in the engine cylinder includes providing the plurality of fuel injections during a non-ballistic region of a curve corresponding to the fuel injector.

15. A pressure-based piston top-dead-center (“TDC”) position measurement system, comprising:
a fuel injector configured to inject fuel into a combustion chamber bounded in part by a piston; and
a controller configured to control the fuel injector to cause a fuel injection when the piston is at each of a plurality of different positions relative to TDC while ensuring fuel is provided to the fuel injector at a substantially constant pressure;
wherein the controller is further configured to estimate a pressure in the combustion chamber in response to each fuel injection, fit a curve to the pressures in the combustion chamber that have been estimated, and determine a TDC position of the piston as correlating with a maximum pressure on the curve.

16. The system of claim 15 , wherein the fuel is provided to the fuel injector at the substantially constant pressure by a fuel accumulator, the controller deactivating an input source to the fuel accumulator before causing the fuel injections.

17. The system of claim 16 , wherein the input source is one of a fuel pump or an inlet metering valve.

18. The system of claim 15 , wherein each of the fuel injections is for a fixed period of time.

19. The system of claim 15 , wherein the controller is configured to estimate a pressure in the combustion chamber using a calculated fuel flow through the fuel injector.

20. The system of claim 15 , wherein the plurality of different positions of the piston includes at least three different positions.

Assignees

• Cummins Inc

Inventors

• Nair Shailesh
• Borate Mayur H
• Mulukutla Srinivas Kumar
• Sahu Panendra Kumar
• Carey David Michael

Classifications

• F02D2200/0602

  Fuel pressure · CPC title

• F02D2200/024

  Fluid pressure of lubricating oil or working fluid · CPC title

• F02D2041/389

  for injecting directly into the cylinder · CPC title

• F02D1/06

  by means dependent on pressure of engine working fluid (F02D1/08 takes precedence) · CPC title

• F02D2250/14

  Timing of measurement, e.g. synchronisation of measurements to the engine cycle · CPC title