METHOD AND APPARATUS FOR PROVIDING FOR HIGH EGR GASEOUS-FUELLED DIRECT INJECTION INTERNAL COMBUSTION ENGINE

• US 20060260585A1
• Filed: 03/28/2006
• Published: 11/23/2006
• Est. Priority Date: 09/30/2003
• Status: Active Grant

• Current Assignee: British Columbia Cancer Agency Branch (Province of British Columbia), Westport Fuel Systems Canada Inc. (Westport Fuel Systems, Inc.)
• Original Assignee: Westport Power Inc. (Westport Fuel Systems, Inc.)
• Inventors: Munshi, Sandeep, Rogak, Steven N., Bushe, W. Kendal, McTaggart-Cowan, Gordon P.
• Granted Patent: US 7,302,918 B2
• Time in Patent Office: Days
• US Class Current: 123/299
• CPC Class Codes: F02B 2275/14 Direct injection into combustion chamber
• CPC Class Codes: F02B 23/0675 the combustion space being substantially spherical, hemispherical, ellipsoid or parabolic
• CPC Class Codes: F02B 29/0406 Layout of the intake air cooling or coolant circuit
• CPC Class Codes: F02B 77/08 Safety, indicating, or supervising devices thermal insulation F02B77/11; monitoring or diagnostic devices for exhaust-gas treatment apparatus F01N11/00
• CPC Class Codes: F02D 13/0265 Negative valve overlap for temporarily storing residual gas in the cylinder
• CPC Class Codes: F02D 19/061 by controlling fuel injectors
• CPC Class Codes: F02D 19/10 peculiar to compression-ignition engines in which the main fuel is gaseous
• CPC Class Codes: F02D 41/0027 the fuel being gaseous non-electrical control F02D19/02
• CPC Class Codes: F02D 41/0072 Estimating, calculating or determining the EGR rate, amount or flow sensors in EGR systems F02M26/45
• CPC Class Codes: F02D 41/144 Sensor in intake manifold
• CPC Class Codes: F02M 25/028 into the charge intakes
• CPC Class Codes: F02M 26/01 Internal exhaust gas recirculation, i.e. wherein the residual exhaust gases are trapped in the cylinder or pushed back from the intake or the exhaust manifold into the combustion chamber without the use of additional passages
• CPC Class Codes: 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
• CPC Class Codes: F02M 26/06 Low pressure loops, i.e. wherein recirculated exhaust gas is taken out from the exhaust downstream of the turbocharger turbine and reintroduced into the intake system upstream of the compressor
• CPC Class Codes: F02M 26/10 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 Class Codes: F02M 26/23 Layout, e.g. schematics
• CPC Class Codes: F02M 26/46 for determining the characteristics of gases, e.g. composition
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies
• CPC Class Codes: Y02T 10/30 Use of alternative fuels, e.g. biofuels
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A method and apparatus adjust pilot fuel injection timing in relation to a main fuel injection timing into a piston cylinder of an operating gaseous-fuelled direct injection internal combustion engine using high levels of EGR. A set of engine parameters are monitored which determine engine load and engine speed and an indicator of EGR concentration within the intake charge. Pilot fuel timing relative to main fuel injection timing is then adjusted according to the engine parameters. High levels of EGR are shown to be tolerated with relatively limited penalties in relation to other emissions typically found with high EGR by reducing the relative injection timing the pilot fuel as compared to main fuel injection timing.

Claims

1. A method of operating a gaseous-fuelled direct injection internal combustion engine defining a combustion chamber, said method comprising:

a. determining an engine speed and engine load for said engine for a cycle of said engine;

b. during said cycle of said engine;

i. directing an intake charge into said combustion chamber, said intake charge having an exhaust gas recirculation (EGR) concentration,

ii. compressing said intake charge within said combustion chamber during a compression stroke of said engine,

iii. directly injecting a gaseous fuel into said combustion chamber at a main fuel timing,

iv. directly injecting a quantity of a pilot fuel into said combustion chamber at a pilot fuel timing relative to said main fuel timing selected by reference to an indicator of said EGR concentration, said engine speed and said engine load, said pilot fuel capable of auto-igniting at a first injection crank angle when a piston is near or at top dead center within said combustion chamber, said combustion chamber partially defined by said piston,

v. burning said gaseous fuel and said pilot fuel, said gaseous fuel ignited as a result of combustion of said pilot fuel.

2. The method of claim 1 wherein said indicator comprises an oxygen concentration in said intake charge.

3. The method of claim 1 wherein said indicator comprises an carbon dioxide concentration in said intake charge.

4. The method of claim 1 wherein said indicator comprises a commanded EGR concentration.

5. The method of claim 1 wherein said indicator comprises an exhaust gas flow through an EGR line, said engine comprising an EGR line.

6. The method of claim 1 wherein said indicator comprises at least one of an exhaust valve timing and an engine load from a previous proximate cycle of said engine.

7. The method of claim 1 wherein said main fuel injection precedes said pilot fuel injection.

8. The method of claim 7 wherein said main fuel injection is when said piston is at or near top dead center near completion of a compression stroke of said engine.

9. The method of claim 1 wherein said exhaust gas concentration is higher than 30%.

10. The method of claim 9 wherein said engine is operating at any point on an engine map of said engine.

11. The method of claim 1 wherein said exhaust gas concentration is between 30% and 50%.

12. The method of claim 1 wherein said gaseous fuel is comprises at least one of:

a. natural gas,

b. methane,

c. propane,

d. liquid petroleum gas,

e. hydrogen,

f. ethane, and

g. blends of natural gas and hydrogen.

13. The method of claim 1 wherein said gaseous fuel is a blend comprising at least two of methane, propane and hydrogen.

14. A gaseous-fuelled direct injection internal combustion engine capable of using exhaust gas recirculation EGR said engine comprising:

a. a controller,

b. a combustion chamber defined by a piston,

c. intake line for introducing a intake charge into said combustion chamber,

d. an main fuel injector for delivering a gaseous fuel to said combustion chamber at a gaseous fuel timing, said gaseous fuel timing being when said piston is at or near top dead center near completion of a compression stroke of said engine,

e. a pilot fuel injector for delivering an auto-ignitable pilot fuel to said combustion chamber at a pilot fuel timing, said pilot fuel injector capable of adjusting said pilot fuel timing and said pilot fuel timing being when said piston is at or near top dead center near completion of said compression stroke of said engine,

f. at least one sensor for monitoring a signal indicative of EGR concentration in said intake charge during a cycle of said engine, said at least one sensor in communication with said controller, said controller in communication with said pilot fuel injector and capable of adjusting said pilot fuel timing relative to said gaseous fuel timing in response to said signal.