Method and apparatus for fuel injection and dynamic combustion control

Patent metadata

Field	Value
Publication number	US-9850827-B2
Application number	US-201415107885-A
Country	US
Kind code	B2
Filing date	Dec 16, 2014
Priority date	Dec 23, 2013
Publication date	Dec 26, 2017
Grant date	Dec 26, 2017

Abstract

Emission targets, such as NOx levels, for gaseous fuelled internal combustion engines that burn a gaseous fuel in a diffusion combustion mode are increasingly more challenging to achieve. A method of fuel injection for an internal combustion engine fuelled with a gaseous fuel comprises introducing a first amount of pilot fuel in a first stage of fuel injection; introducing a first amount of main fuel (the gaseous fuel) in a second stage of fuel injection; and introducing a second amount of main fuel in a third stage of fuel injection. The first and second amounts of main fuel contribute to load and speed demand of the internal combustion engine. Engine maps calibrated for different engine performance can be employed in different regions of the load and speed range of the engine. The engine maps are blended when the engine transitions between two regions; and momentary excursions into different regions do not change the engine calibration.

First claim

What is claimed is:

1. A method of fuel injection for an internal combustion engine fuelled with a gaseous fuel comprising:
introducing a first amount of pilot fuel in a first stage of fuel injection;
introducing a first amount of main fuel in a second stage of fuel injection; and
introducing a second amount of main fuel in a third stage of fuel injection, said first and second amounts of main fuel contribute to load and speed demand of said internal combustion engine;
wherein said main fuel is said gaseous fuel, and said pilot fuel and said main fuel burn in a diffusion combustion mode.

2. The method of claim 1 , wherein when an operating point of said internal combustion engine transitions from a first characteristic region to a second characteristic region, for at least one of said first, second and third stages of fuel injection the method further comprising:
employing calibrations from a first engine map after said operating point transitions into said second characteristic region while a first measured parameter is less than a first predetermined threshold;
while said first measured parameter is between said first predetermined threshold and a second predetermined threshold:
blending calibrations from said first engine map and a second engine map; and
employing said blended calibrations; and

employing calibrations from said second engine map when said first measured parameter is greater than said second predetermined threshold.

3. The method of claim 2 , wherein at least one of:
said first measured parameter is time and said first and second predetermined thresholds are first and second predetermined time thresholds respectively; and
said first measured parameter is a temperature characteristic of combustion temperature and said first and second predetermined thresholds are first and second predetermined temperature thresholds respectively.

4. The method of claim 2 further comprising employing said first engine map in said first characteristic region.

5. The method of claim 2 wherein at least one of:
said calibrations from said first and second engine maps comprise fuelling and timing calibrations; and
a ratio is employed to blend said first and second engine maps.

6. The method of claim 1 wherein at least one of:
said first stage of fuel injection occurs between 50° BTDC and 10° BTDC; and
said second stage of fuel injection occurs between 30° BTDC and 0° BTDC; and
said third stage of fuel injection occurs between 20° BTDC and 20° ATDC; and
a separation timing between an ending of a fuel injection pulse employed in said first stage of fuel injection and a beginning of a fuel injection pulse employed in said second stage of fuel injection is between 200 and 400 microseconds; and
a separation timing between an ending of a fuel injection pulse employed in said second stage of fuel injection and a beginning of a fuel injection pulse employed in said third stage of fuel injection is between 500 and 750 microseconds.

7. The method of claim 1 further comprising at least one of:
introducing a second amount of pilot fuel in a fourth stage of fuel injection; and
introducing a second amount of pilot fuel in a fourth stage of fuel injection, wherein said fourth stage of fuel injection occurs between 0° ATDC and 50° ATDC.

8. An apparatus for fuel injection in an internal combustion engine fuelled with a gaseous fuel comprising:
a direct injection apparatus for directly introducing a pilot fuel and a main fuel into a combustion chamber of said internal combustion engine, said main fuel is said gaseous fuel;
a pilot fuel supply system delivering said pilot fuel to said direct injection apparatus;
a main fuel supply system delivering said main fuel to said direct injection apparatus;
a controller configured to actuate said direct injection apparatus to introduce said pilot fuel and said main fuel into said combustion chamber, and programmed to:
actuate said direct injection apparatus in a first stage of fuel injection to introduce a first amount of pilot fuel;
actuate said direct injection apparatus in a second stage of fuel injection to introduce a first amount of main fuel; and
actuate said direct injection apparatus in a third stage of fuel injection to introduce a second amount of main fuel, said first and second amounts of main fuel contribute to load and speed demand of said internal combustion engine;

wherein said pilot fuel and said main fuel burn in a diffusion combustion mode.

9. The apparatus of claim 8 , wherein when an operating point of said internal combustion engine transitions from a first characteristic region to a second characteristic region, for at least one of said first, second and third stages of fuel injection said controller is further programmed to:
employ calibrations from a first engine map after said operating point transitions into said second characteristic region while a first measured parameter is less than a first predetermined threshold;
while said first measured parameter is between said first predetermined threshold and a second predetermined threshold:
blend calibrations from said first engine map and a second engine map; and
employ said blended calibrations; and

employ calibrations from said second engine map when said first measured parameter is greater than said second predetermined threshold.

10. The apparatus of claim 9 wherein at least one of:
said first measured parameter is time and said first and second predetermined thresholds are first and second predetermined time thresholds respectively; and
said first measured parameter is a temperature characteristic of combustion temperature and said first and second predetermined thresholds are first and second predetermined temperature thresholds respectively.

11. The apparatus of claim 9 wherein at least one of:
said controller is further programmed to employ said first engine map in said first characteristic region; and
said calibrations from said first and second engine maps comprise fuelling and timing calibrations; and
a ratio is employed to blend said first and second engine maps.

12. The apparatus of claim 8 wherein at least one of:
said first stage of fuel injection occurs between 50° BTDC and 10° BTDC; and
said second stage of fuel injection occurs between 30° BTDC and 0° BTDC; and
said third stage of fuel injection occurs between 20° BTDC and 20° ATDC.

13. The apparatus of claim 8 wherein at least one of:
a separation timing between an ending of a fuel injection pulse employed in said first stage of fuel injection and a beginning of a fuel injection pulse employed in said second stage of fuel injection is between 200 and 400 microseconds; and
a separation timing between an ending of a fuel injection pulse employed in said second stage of fuel injection and a beginning of a fuel injection pulse employed in said third stage of fuel injection is between 500 and 750 microseconds.

14. The apparatus of claim 8 wherein at least one of:
said controller is further programmed to actuate said direct injection apparatus in a fourth stage of fuel injection to introduce a second amount of pilot fuel; and
said controller is further programmed to actuate said direct injection apparatus in a fourth stage of fuel injection to introduce a second amount of pilot fuel, and said fourth stage of fuel injection occurs between 0° ATDC and 50° ATDC.

15. The apparatus of claim 8 wherein at least one of:
said direct injection apparatus comprises a concentric needle fuel injection valve; and
said direct injection apparatus comprises a pilot fuel direct injector operativ

Assignees

• Westport Power Inc

Inventors

• Fei Wei
• Walker James D
• Mctaggart-Cowan Gordon P
• Mann Kenneth R

Classifications

• F02D35/025

  by determining temperatures inside the cylinder, e.g. combustion temperatures · CPC title

• F02D41/3064

  with special control during transition between modes · CPC title

• F02B43/00

  Engines characterised by operating on gaseous fuels; Plants including such engines (engines characterised by the gas-air charge being ignited by compression ignition of an additional fuel F02B7/06; engines convertible from gas to other fuel consumption F02B69/04) · CPC title

• F02D41/0025

  Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures · CPC title

• F02D41/401

  Controlling injection timing (F02D41/402 takes precedence) · CPC title