System and method of operating an internal combustion engine

Patent metadata

Field	Value
Publication number	US-10094324-B2
Application number	US-201313905691-A
Country	US
Kind code	B2
Filing date	May 30, 2013
Priority date	May 30, 2013
Publication date	Oct 9, 2018
Grant date	Oct 9, 2018

Abstract

A method of operating an internal combustion engine is provided. The method includes combusting a mixture of fresh air and fuel within multiple cylinders. The method also includes directing a first portion of exhaust gases into a first-stage turbine and a second-stage turbine of a turbocharger for expanding the exhaust gases, directing a second portion of exhaust gases from the exhaust manifold via an exhaust channel bypassing the first-stage turbine and recirculating a third portion of exhaust gases into an intake manifold after mixing with fresh air. The method includes controlling at least one of: reducing a normal engine speed at each engine power setting while maintaining constant engine power level by increasing a fuel injection per cycle; concurrently increasing a flow rate of the third portion of exhaust gas during recirculation; and advancing a fuel injection timing for reducing emission levels that meets Tier 4 requirements.

First claim

The invention claimed is:

1. A method of operating an internal combustion engine, the method comprising:
combusting a mixture of a flow of fresh air and a fuel within a plurality of cylinders, wherein the fuel is injected from a fuel injection system into the plurality of cylinders;
directing a first portion of exhaust gases from an exhaust manifold into a first-stage turbine and a second-stage turbine of a turbocharger for expanding the first portion of the exhaust gases;
recirculating a second portion of exhaust gases from the exhaust manifold into an intake manifold after mixing with the flow of fresh air; and
reducing nitrogen oxide (NOx) and particulate matter (PM) emission levels by
reducing the engine speed while operating the internal combustion engine at a given engine power while further maintaining the given engine power constant by increasing a fuel injection duration per cycle for increasing torque; and
concurrently increasing a flow rate of the second portion of exhaust gas during recirculation;
advancing a fuel injection timing.

2. The method of claim 1 , further comprising increasing an injection pressure at a given engine power while reducing the engine speed at each engine power setting for maintaining constant engine power level.

3. The method of claim 1 , further comprising reducing the engine speed at the given engine power based on not exceeding a threshold limit of a plurality of operating parameters comprising peak cylinder pressures and engine shaft bearing loads.

4. The method of claim 1 , further comprising reducing the engine speed at a given engine power based on an air-handling system requirement of an oxygen-to-fuel ratio of at least a threshold value for respective engine power.

5. The method of claim 4 , further comprising increasing a boost pressure for maintaining the oxygen-to-fuel ratio of at least a threshold value at each engine power setting by controlling at least one of a variable valve position in the exhaust channel bypassing the first stage turbine, a variable geometry turbocharger, a supercharger, and a subsystem of a plurality of compressors arranged for increasing the boost pressure.

6. The method of claim 1 , wherein the flow rate of the exhaust gas recirculation is increased by about 40 percent while advancing the fuel injection timing.

7. The method of claim 1 , further comprising concurrently reducing the engine speed, increasing the exhaust gas recirculation, advancing the fuel injection timing, increasing an injection pressure and lowering a compression ratio in response to both the nitrogen oxide (NOx) and particulate matter (PM) emission levels of the exhaust gases of the engine.

8. The method of claim 7 , further comprising lowering the compression ratio in each cylinder from about 17.1 to about 15.1.

9. The method of claim 1 , further comprising reducing the engine speed in real time in response to a maximum emission levels of nitrogen oxide (NOx) detected by a sensing system in exhaust gases and particulate matter (PM) inferred from the sensing of oxygen-to-fuel ratio in the intake manifold.

10. The method of claim 1 , further comprising cooling the second portion of exhaust gases prior to entering the intake manifold by an exhaust gas recirculation cooler.

11. The method of claim 1 , further comprising cooling the fresh air using one or more heat exchangers in an intake channel having a first stage compressor and a second-stage compressor.

12. The method of claim 1 , wherein the operating of the internal combustion engine in accordance with a Miller cycle comprises:
moving a piston from a top dead center position towards a bottom dead center position in an engine cylinder;
closing an intake valve of the internal combustion engine when the piston is about the bottom dead center position in the engine cylinder during an intake stroke;
opening an exhaust valve for a predetermined time period when the piston is about the bottom dead center position of the engine cylinder after closing the intake valve during an exhaust stroke so as to exhaust a predetermined quantity of fresh charge from the engine cylinder via the exhaust valve.

13. A system comprising:
an internal combustion engine comprising a plurality of cylinders of the engine for combusting a mixture of fresh air and fuel;
a fuel injection system for injecting fuel into the plurality of cylinders of the engine;
a turbocharger unit including a turbine coupled via a turbocharger shaft to a compressor, wherein the compressor is configured to receive the fresh air and discharge a compressed air stream to an intake manifold of the internal combustion engine;
a first flow path for allowing a first portion of exhaust gases from an exhaust manifold into the turbine for expanding the first portion of the exhaust gases;
a second flow path for allowing a second portion of exhaust gases from the exhaust manifold via an exhaust channel bypassing a first-stage turbine;
a third flow path for recirculating a third portion of exhaust gases from the exhaust manifold into the intake manifold after mixing with the fresh air; and
a controller comprising a plurality of sensors for sensing a plurality of operating parameters, wherein the controller is configured to reduce nitrogen oxide (NOx) and particulate matter (PM) emission levels by a) reducing the engine speed at a given engine power while maintaining the given engine power constant by increasing a fuel injection duration per cycle for increasing torque, b) increasing a flow rate of the exhaust gas recirculation, c) increasing injection pressure, and d) advancing a fuel injection timing.

14. The system of claim 13 , wherein the controller is further configured to lower the compression ratio in each cylinder from about 17.1 to about 15.1.

15. The system of claim 13 , further comprising an exhaust gas recirculation cooler located in the third flow path carrying the third portion of exhaust gases into the intake manifold and one or more intercoolers located in an intake channel having a first stage compressor and a second stage compressor.

16. The system of claim 14 , wherein the third flow path comprises an EGR control valve for controlling the flow of the second portion of the exhaust gases.

17. The system of claim 13 , wherein the controller is configured to concurrently increase the exhaust gas recirculation (EGR) and advance the fuel injection timings in response to both the nitrogen oxide (NOx) and particulate matter (PM) emission levels of the exhaust gases of the engine.

18. The system of claim 13 , wherein the controller is configured to concurrently reduce the engine speed at each engine power setting based on a plurality of operating parameters comprising peak cylinder pressures and engine shaft bearing loads, an air-handling system requirement of an oxygen-to-fuel ratio of at least a threshold value at the respective engine power setting, and increase the exhaust gas recirculation and advance the fuel injection timing in response to both the nitrogen oxide (NOx) and particulate matter (PM) emission levels of the exhaust gases of the engine.

19. A controller for an internal combustion engine, comprising:
a plurality of sensors for sensing a plurality of operating parameters of the engine;
a control unit configured to reduce nitrogen oxide (NOx) and particulate matter (PM) emission levels of the engine at each engine power setting
by a) concurrently reducing the engine speed at corresponding engine power setting while maintaining the engine power constant by increasing a

Assignees

• Gen Electric

Inventors

• Lavertu Thomas Michael
• Klingbeil Adam Edgar
• Primus Roy James
• Akinyemi Omowoleola Chukwuemeka
• Gummadavelli Venu Gopal
• Record Barry Allen
• Yager James Henry

Classifications

• F02M26/10

  having means to increase the pressure difference between the exhaust and intake system, e.g. venturis, variable geometry turbines, check valves using pressure pulsations or throttles in the air intake or exhaust system · CPC title

• F02B37/18

  by bypassing exhaust {from the inlet to the outlet of turbine or to the atmosphere} · CPC title

• F02D31/001

  Electric control of rotation speed · CPC title

• F02M26/23

  Layout, e.g. schematics · CPC title

• F02D2250/18

  Control of the engine output torque · CPC title