Engine having hotspot fuel igniter and piston and methodology using same

Patent metadata

Field	Value
Publication number	US-12565865-B2
Application number	US-202418585190-A
Country	US
Kind code	B2
Filing date	Feb 23, 2024
Priority date	Feb 23, 2024
Publication date	Mar 3, 2026
Grant date	Mar 3, 2026

Abstract

An engine includes a piston movable within a combustion cylinder, a direct fuel injector, and a hotspot fuel igniter. The hotspot fuel igniter includes a core exposed to the combustion cylinder, to ignite fuel spray plumes of a directly injected fuel, and an insulator insulating the core from heat transfer with a material of the piston. Applications include igniting a range of fuels, including lower cetane number fuels.

First claim

What is claimed is:

1 . An engine comprising:
an engine housing including a cylinder block and a cylinder head, and having a combustion cylinder formed therein; a piston movable within the combustion cylinder; a direct fuel injector extending into the combustion cylinder and including a plurality of spray orifices; and a hotspot fuel igniter within the piston including a core exposed to the combustion cylinder, and an insulator extending at least partially around the core.

2 . The engine of claim 1 further comprising an ignition aid supported in the cylinder head.

3 . The engine of claim 1 wherein the hotspot fuel igniter further includes a plug, and the insulator extends between the core and the plug.

4 . The engine of claim 1 wherein the core includes a fuel-impingement edge.

5 . The engine of claim 1 wherein an air gap clearance is defined between the hotspot fuel igniter and a material of the piston.

6 . The engine of claim 1 wherein the plurality of spray orifices define a plurality of fuel spray axes through the combustion cylinder, and the hotspot fuel igniter is one of a plurality of hotspot fuel igniters arranged in a regular pattern relative to the plurality of fuel spray axes.

7 . The engine of claim 6 wherein the regular pattern includes an angularly offset pattern relative to the plurality of fuel spray axes, circumferentially around a piston center axis.

8 . The engine of claim 1 wherein the piston includes an annular piston rim extending circumferentially around a combustion bowl, and the hotspot fuel igniter is attached to the annular piston rim.

9 . A piston comprising:
a piston crown formed of a piston crown material, and including a piston crown surface forming an annular piston rim extending circumferentially around a piston center axis; and a plurality of hotspot fuel igniters mounted in the piston crown and each including a core positioned so as to be impinged by an attached flow of a fuel along the piston crown surface, and an insulator insulating the core from the piston crown material.

10 . The piston of claim 9 wherein each respective core includes a fuel-impingement edge.

11 . The piston of claim 10 wherein each fuel-impingement edge is one of a plurality of fuel-impingement edges of each respective hotspot fuel igniter.

12 . The piston of claim 10 wherein the plurality of hotspot fuel igniters each include a plug positioned in a bore in the piston crown and supporting the respective core.

13 . The piston of claim 12 wherein an air gap clearance is defined between each respective plug and the piston crown.

14 . The piston of claim 13 wherein each respective plug defines a plug axis, and the air gap clearance includes an axial air gap clearance and a radial air gap clearance.

15 . The piston of claim 13 wherein the insulator includes a solid phase insulator between the respective plug and core.

16 . The piston of claim 9 wherein the annular piston rim extends circumferentially around a combustion bowl, and the plurality of hotspot fuel igniters includes hotspot fuel igniters within the annular piston rim and hotspot fuel igniters within the combustion bowl.

17 . A method of operating an engine comprising:
directly injecting a fuel into a combustion cylinder in an engine; impinging a plurality of plumes of the directly injected fuel upon a plurality of hotspot fuel igniters in a piston crown of a piston in the combustion cylinder and insulated from heat transfer with a material of the piston; and igniting the plurality of plumes of the directly injected fuel based at least in part upon retained heat of the plurality of hotspot fuel igniters.

18 . The method of claim 17 wherein the impinging a plurality of plumes includes impinging the plurality of plumes upon a fuel-impingement edge of each respective one of the plurality of hotspot fuel igniters exposed to an attached flow of one of the plurality of plumes along a piston crown surface of the piston crown.

19 . The method of claim 17 wherein the directly injected fuel includes a fuel having a cetane number below about 35.

Assignees

• Caterpillar Inc

Inventors

• Koci Chad P
• Coldren Dana R

Classifications

• F02F3/26

  having combustion chamber in piston head (the surface thereof being covered F02F3/14) · CPC title

• F02B2075/125

  Direct injection in the combustion chamber for spark ignition engines, i.e. not in pre-combustion chamber · CPC title

• F02B23/10

  with separate admission of air and fuel into cylinder · CPC title

• F02B9/06

  with non-timed positive ignition, e.g. with hot-spots · CPC title

• F02F3/285 Primary

  the head being provided with an insert located in or on the combustion-gas-swept surface · CPC title