# US 11,078,826 B1 · Gaseous fuel engine and sparkless operating strategy therefor

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- Number: US 11,078,826 B1
- Document ID: US11078826B1
- Status: Granted
- Kind: B1
- Application number: 17/082,401
- Filed: 2020-10-28
- Granted: 2021-08-03
- Earliest claimed: 2020-10-28
- Assignees: Caterpillar Inc.
- Applicants: Caterpillar Inc.
- Inventors: David Yu-Zhang Chang
- Web page: https://patentgrep.com/patent/US11078826B1

## CPC

- F02B 19/12: with positive ignition (engines with non-timed positive ignition, and with incandescent chambers F02B9/08)
- F02B 19/06: with auxiliary piston in chamber for transferring ignited charge to cylinder space
- F02B 19/14: with compression ignition
- F02D 19/024: {by controlling fuel injectors}
- F02D 41/0027: {the fuel being gaseous (non-electrical control F02D19/02)}
- F02M 21/0275: {for in-cylinder direct injection, e.g. injector combined with spark plug}
- F02B 19/108: {with fuel injection at least into pre-combustion chamber, i.e. injector mounted directly in the pre-combustion chamber}
- F02P 13/00: Sparking plugs structurally combined with other parts of internal-combustion engines ({connection of ignition coil to spark plug connector F02P3/02;} with fuel injectors F02M57/06 {; spark plug connector per se H01T13/04 – H01T13/06; predominant aspects of sparking plug, see H01T13/40 – H01T13/44})
- Y02T 10/12: Improving ICE efficiencies
- Y02T 10/30: Use of alternative fuels, e.g. biofuels
- F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G)
- F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W)
- F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02P: IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES ({anti-pollution means for internal-combustion engines F02B17/00}; specially adapted for rotary-piston or oscillating-piston engines F02B53/12; {ignition of gas turbine plants F02C7/26; ignition of jet propulsion plants F02K9/95; starting of combustion engines F02N9/00}; ignition of combustion apparatus in general, glowing plugs F23Q; measuring of physical variables in general G01; controlling in general G05; data processing in general G06; electrical components in general see Section H; {ignition coils H01F38/12}; sparking plugs H01T13/00)
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

Operating an internal combustion engine system includes advancing a prechamber piston in a fuel delivery igniter to push a main charge of fuel from a prechamber into a cylinder, and advancing the prechamber piston to compression-ignite a pilot charge within the prechamber. Combustion gases of the pilot charge are conveyed into the cylinder to ignite the main charge. Operation of the engine system provides sparkless gaseous fuel ignition.

## Claims

### Claim 1

A method of operating an internal combustion engine system comprising:
advancing a prechamber piston in a fuel delivery igniter to push a main charge of fuel from a prechamber in the fuel delivery igniter into a cylinder in an internal combustion engine;
advancing the prechamber piston in the fuel delivery igniter to compression-ignite a pilot charge of the fuel within the prechamber;
conveying combustion gases of the compression-ignited pilot charge of the fuel from the prechamber into the cylinder;
igniting the main charge of fuel in the cylinder by way of the combustion gases of the compression-ignited pilot charge; and
urging a main piston in the internal combustion engine toward a bottom-dead-center (BDC) position in a power stroke based on combustion of the main charge of fuel ignited by way of the combustion gases of the compression-ignited pilot charge.

### Claim 2 (depends on 1)

The method of claim 1 wherein the fuel is a gaseous fuel.

### Claim 3 (depends on 2)

The method of claim 2 wherein the gaseous fuel includes hydrogen.

### Claim 4 (depends on 2)

The method of claim 2 further comprising supplying all of the main charge of fuel and the pilot charge of fuel into the prechamber through a fuel inlet in the fuel delivery igniter separate from a nozzle outlet in the fuel delivery igniter.

### Claim 5 (depends on 4)

The method of claim 4 further comprising stopping or reversing the prechamber piston between the pushing of the main charge of fuel and the compression-igniting of the pilot charge of fuel.

### Claim 6 (depends on 2)

The method of claim 2 wherein:
the advancing of the prechamber piston to push a main charge occurs at least in part during an intake stroke of the main piston; and
the advancing of the prechamber piston to compression-ignite a pilot charge occurs at least in part during a compression stroke of the main piston.

### Claim 7 (depends on 6)

The method of claim 6 wherein:
the advancing of the prechamber piston to push a main charge includes advancing the prechamber piston at a slower speed; and
the advancing of the prechamber piston to compression-ignite a pilot charge includes advancing the prechamber piston at a faster speed.

### Claim 8 (depends on 2)

The method of claim 2 wherein the prechamber piston is hydraulically actuated, and further comprising blocking a hydraulic actuation chamber for the prechamber piston from a drain to initiate the advancing of the prechamber piston to push a main charge, and to initiate the advancing of the prechamber piston to compression-ignite a pilot charge.

### Claim 9

A fuel system for a gaseous fuel engine comprising:
a gaseous fuel conduit;
a fuel delivery igniter including a housing having formed therein each of a prechamber, a fuel inlet to the prechamber fluidly connected to the gaseous fuel conduit, and a nozzle outlet from the prechamber, and further including a prechamber piston movable in the prechamber between a retracted position and an advanced position;
a fueling and ignition control system including an electronically controlled actuator structured to advance the prechamber piston through the prechamber, and an electronic control unit coupled with the electronically controlled actuator;
the electronic control unit is structured to:
monitor an engine timing of a gaseous fuel engine in an engine cycle;
command advancing the prechamber piston, using the electronically controlled actuator, according to an earlier engine timing in the engine cycle such that the prechamber piston pushes a main charge of gaseous fuel from the prechamber through the nozzle outlet; and
command advancing the prechamber piston, using the electronically controlled actuator, according to a later engine timing in the engine cycle such that the prechamber piston compression-ignites a pilot charge of the gaseous fuel within the prechamber.

### Claim 10 (depends on 9)

The fuel system of claim 9 wherein the earlier engine timing occurs during an intake stroke of a main piston in the gaseous fuel engine, and the later engine timing occurs during a compression stroke of the main piston.

### Claim 11 (depends on 10)

The fuel system of claim 10 wherein the advancing of the prechamber piston according to the earlier engine timing occurs at a slower prechamber piston speed, and the advancing of the prechamber piston according to the later engine timing occurs at a faster prechamber piston speed.

### Claim 12 (depends on 11)

The fuel system of claim 11 wherein the electronic control unit is further structured to command stopping or reversing of the prechamber piston after the pushing of the main charge of gaseous fuel and prior to the compression-igniting of the pilot charge of gaseous fuel.

### Claim 13 (depends on 9)

The fuel system of claim 9 wherein the housing has a hydraulic control chamber formed therein, and the electronically controlled actuator includes a piston head of the prechamber piston exposed to a fluid pressure of the hydraulic control chamber, and a chamber pressure control valve.

### Claim 14 (depends on 13)

The fuel system of claim 13 further comprising a gaseous fuel supply, a fuel pressure regulator positioned fluidly between the gaseous fuel supply and the gaseous fuel conduit, and a gaseous fuel admission valve positioned fluidly between the gaseous fuel supply and the fuel pressure regulator.

### Claim 15 (depends on 14)

The fuel system of claim 14 wherein the gaseous fuel includes hydrogen and the gaseous fuel supply includes at least one of a hydrogen tank or a reformer.

### Claim 16

A method for sparkless operation of a gaseous fuel internal combustion engine system comprising:
feeding a gaseous fuel from a gaseous fuel supply into a prechamber in a fuel delivery igniter;
pushing unignited gaseous fuel from the prechamber into a cylinder in a gaseous fuel engine using a prechamber piston during an intake stroke of a main piston in the cylinder;
mixing the unignited gaseous fuel with air in the cylinder;
compression-igniting gaseous fuel in the prechamber using the prechamber piston;
conveying combustion gases of the compression-ignited gaseous fuel into the mixture of unignited gaseous fuel and air; and
igniting the mixture of unignited gaseous fuel and air by way of the combustion gases of the compression-ignited gaseous fuel.

### Claim 17 (depends on 16)

The method of claim 16 further comprising hydraulically actuating the prechamber piston to push the unignited gaseous fuel into the cylinder, and hydraulically actuating the prechamber piston to compression-ignite the gaseous fuel in the prechamber.

### Claim 18 (depends on 17)

The method of claim 17 further comprising moving the prechamber piston at a slower speed to push the unignited gaseous fuel into the cylinder, and moving the prechamber piston at a faster speed to compression-ignite the gaseous fuel in the prechamber.

### Claim 19 (depends on 18)

The method of claim 18 further comprising stopping or reversing the prechamber piston between the pushing of the unignited gaseous fuel and the compression-igniting of the gaseous fuel.

### Claim 20 (depends on 18)

The method of claim 18 wherein the gaseous fuel includes hydrogen.