Transient controller and method of operating gas engine

Patent metadata

Field	Value
Publication number	US-11174800-B2
Application number	US-201916580850-A
Country	US
Kind code	B2
Filing date	Sep 24, 2019
Priority date	Sep 24, 2019
Publication date	Nov 16, 2021
Grant date	Nov 16, 2021

Abstract

A controller for an internal combustion engine of a generator set operates the engine at a first, low load condition at a lean air/fuel ratio using hydrogen fuel, and at a second, high load condition at a richer air/fuel ratio using gaseous fuel. The controller transitions from the first condition to the second condition by adding gaseous fuel to achieve the richer air/fuel ratio during a transient event.

First claim

The invention claimed is:

1. An internal combustion engine, comprising:
a cylinder block forming a cylinder;
a gaseous fuel supply providing a gaseous fuel selectively to the cylinder via a gas injector;
a hydrogen fuel supply providing a hydrogen fuel selectively to the cylinder via a hydrogen fuel injector;
a power output shaft arranged to receive a power output of the engine, the power output shaft mechanically connected with a piston disposed reciprocally in the cylinder;
a controller controlling operation of the gas and hydrogen fuel injectors, the controller configured to operate the engine at a baseline engine speed in a first condition in which the power output shaft transfers a first load, the first condition including a first air/fuel ratio in which a majority of fuel is hydrogen fuel and the cylinder is operating using an ultra-lean mixture of air and hydrogen, and at the baseline engine speed in a second condition in which the power output shaft transfers a second load that is higher than the first load, the second condition including a second air/fuel ratio in which a majority of fuel is gaseous fuel;
wherein the controller is programmed to transition from the first condition to the second condition when the controller determines that a speed of the engine droops below the baseline engine speed by adding both additional gaseous fuel and additional hydrogen fuel to achieve the second air/fuel ratio during a transient event in which the first load increases to the second load, wherein the additional gaseous fuel is increased incrementally while the engine has not yet reached the second load, and wherein the additional hydrogen fuel is also increased incrementally until the controller detects pre-ignition to be occurring in the cylinder.

2. The internal combustion engine of claim 1 , wherein the first air/fuel ratio is between 2.5 and 4.

3. The internal combustion engine of claim 1 , further comprising an intake plenum and an exhaust collector fluidly connected with the cylinder, and a turbocharger connected across the intake plenum and the exhaust collector.

4. The internal combustion engine of claim 3 , wherein the gaseous fuel is mixed with incoming air upstream of the turbocharger and delivered to the intake plenum.

5. The internal combustion engine of claim 3 , wherein the hydrogen fuel is provided directly to the intake plenum.

6. The internal combustion engine of claim 1 , wherein the controller operates to adjust an amount of gaseous fuel provided to the cylinder based on a magnitude of the second load.

7. The internal combustion engine of claim 1 , wherein the controller further operates to determine whether the pre-ignition is occurring in the cylinder, and wherein the controller is further configured to cease increasing an amount of hydrogen fuel provided to the cylinder when pre-ignition is detected to be occurring in the cylinder.

8. The internal combustion engine of claim 7 , wherein the controller is configured to increase the amount of hydrogen fuel while pre-ignition is not occurring, and to decrease the amount of hydrogen fuel when pre-ignition occurs.

9. A controller for an internal combustion engine, the internal combustion engine having a cylinder block forming a cylinder, a gaseous fuel supply providing a gaseous fuel selectively to the cylinder via a gaseous fuel injector, a hydrogen fuel supply providing a hydrogen fuel selectively to the cylinder via a hydrogen fuel injector, and a power output shaft arranged to receive a power output of the engine, the power output shaft mechanically connected with a piston disposed reciprocally in the cylinder, the controller is configured to:
at times, operate the engine at a baseline engine speed in a first condition in which the power output is low, wherein the first condition includes operating the engine at an ultra-lean first air/fuel ratio in which a majority of fuel provided to the cylinder is hydrogen fuel;
transition from the first condition to a second condition in response to a step increase in load demand while the engine continues to operate at the baseline engine speed, wherein the transition includes incrementally increasing the gaseous fuel supply to the cylinder and also incrementally increasing the hydrogen fuel supply to the cylinder; and
operate the engine at the second condition in which the power output is high, wherein the second condition includes operating the engine at a second air/fuel ratio in which a majority of fuel provided to the cylinder is gaseous fuel.

10. The controller of claim 9 , wherein the first air/fuel ratio is between 2.5 and 4.

11. The controller of claim 9 , wherein the engine further comprises an intake plenum and an exhaust collector fluidly connected with the cylinder, and a turbocharger connected across the intake plenum and the exhaust collector.

12. The controller of claim 11 , wherein the controller is further configured to cause the gaseous fuel to mix with incoming air upstream of the turbocharger and delivering a mixture at the second air/fuel ratio to the intake plenum.

13. The controller of claim 11 , wherein the controller is further configured to cause the hydrogen fuel to mix directly into the intake plenum.

14. The controller of claim 9 , wherein the controller is further configured to adjust the second air/fuel ratio based on a magnitude of the load demand.

15. The controller of claim 9 , wherein the controller is further configured to determine whether a pre-ignition is occurring in the cylinder, and cease an incremental increase of the hydrogen fuel supply to the cylinder based on presence of pre-ignition in the cylinder.

16. The controller of claim 15 , wherein the controller is further configured to increase the amount of hydrogen fuel while pre-ignition is not occurring, and decrease the amount of hydrogen fuel when pre-ignition occurs.

17. A method for operating an internal combustion engine, the method comprising:
operating the engine at a baseline engine speed at an initial state using primarily a hydrogen fuel at an initial air/fuel ratio that is ultra-lean, the initial state having an initial power output;
determining that a transient event is present, the transient event requiring the engine to transition to a final power output while remaining at the baseline engine speed, wherein the final power output is larger than the initial power output;
activating a transient controller upon determining that the transient event is present, the transient controller operating to:
add a gaseous fuel to enrich the initial air/fuel ratio to a final air/fuel ratio;
control an amount of the gaseous fuel added based on the final power output; and
increase an amount of the hydrogen fuel based on whether pre-ignition is present in at least one engine cylinder.

18. The method of claim 17 , wherein the initial air/fuel ratio is between 2.5 and 4.

19. The method of claim 17 , wherein the transient controller adds gaseous fuel and hydrogen fuel simultaneously when an engine speed drops below a threshold.

20. The method of claim 17 , wherein the transient controller increases an amount of hydrogen fuel while pre-ignition is not occurring, and decreases the amount of hydrogen fuel when pre-ignition occurs.

Assignees

• Caterpillar Inc

Inventors

• Wang Paul
• Maxson Robert J
• Ginter David M
• Bardell Michael

Classifications

• 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

• F02D19/0647

  the gaseous fuel being liquefied petroleum gas [LPG], liquefied natural gas [LNG], compressed natural gas [CNG] or dimethyl ether [DME] · CPC title

• F02D19/0615 Primary

  being initiated by automatic means, e.g. based on engine or vehicle operating conditions · CPC title

• F02D41/0027

  the fuel being gaseous (non-electrical control F02D19/02) · CPC title

• F02D31/007

  controlling fuel supply · CPC title