# US 10,374,383 B2 · Laser ignition device

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- Number: US 10,374,383 B2
- Document ID: US10374383B2
- Status: Granted
- Kind: B2
- Application number: 15/952,762
- Filed: 2018-04-13
- Published: 2018-10-25
- Granted: 2019-08-06
- Earliest claimed: 2017-04-24
- Assignees: Inter-University Research Institute Corporation National Institutes of Natural Sciences
- Applicants: Inter-University Research Institute Corporation National Institutes of Natural Sciences
- Inventors: Takunori Taira; Hwan Hong Lim
- Web page: https://patentgrep.com/patent/US10374383B2

## CPC

- H01S 3/1115: using intracavity saturable absorbers
- F02P 23/04: Other physical ignition means, e.g. using laser rays
- H01S 3/0627: {the resonator being monolithic, e.g. microlaser}
- H01S 3/10038: {Amplitude control}
- H01S 3/1022: {by controlling the optical pumping}
- F02P 5/00: Advancing or retarding ignition; Control therefor
- H01S 3/0014: {Monitoring arrangements not otherwise provided for (photometry G01J1/00, e.g. G01J1/4257; radiation pyrometry G01J5/00; measuring coherence of light G01J9/00; measuring wavelength of light G01J9/00, e.g. G01J9/0246; measuring optical pulses G01J11/00; calorimetrically measuring power of laser beams G01K17/003)}
- H01S 3/0612: {Non-homogeneous structure (H01S3/07 takes precedence)}
- H01S 3/094053: {Fibre coupled pump, e.g. delivering pump light using a fibre or a fibre bundle}
- H01S 3/094076: {Pulsed or modulated pumping (H01S3/1024 takes precedence)}
- H01S 3/09415: {the pumping beam being parallel to the lasing mode of the pumped medium, e.g. end-pumping}
- H01S 3/113: using intracavity saturable absorbers
- H01S 3/1611: {neodymium}
- H01S 3/1643: {YAG}
- H01S: DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- 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)

## Abstract

To provide a laser ignition device in which the ignition efficiency is improved and the laser pulse energy necessary for ignition is minimized by optimizing the pulse time width of laser. The laser ignition device includes: a pulse laser oscillator 1 configured to output a beam having a wavelength λ [μm] and a beam quality M2; an energy controller 2 configured to control energy of pulse laser outputted from the pulse laser oscillator 1; a lens 3 having a focal length f [mm] and configured to focus the pulse laser outputted from the pulse laser oscillator 1; and a pulse time width controller 14 configured to control a time width of the pulse laser, wherein the pulse time width controller 14 controls the time width of the pulse laser to be 0.6 to 2 ns.

## Claims

### Claim 1

A laser ignition device comprising:
a pulse laser oscillator configured to output a beam having a wavelength λ [μm] and a beam quality M2;
an energy controller configured to control energy of pulse laser outputted from the pulse laser oscillator;
a lens having a focal length f [mm] and configured to focus the pulse laser outputted from the pulse laser oscillator; and
a pulse time width controller configured to control a time width of the pulse laser, wherein
the pulse time width controller controls the time width of the pulse laser to be 0.57 to 0.63 ns.

### Claim 2 (depends on 1)

The laser ignition device according to claim 1, wherein the M2 is less than 4.

### Claim 3 (depends on 1)

The laser ignition device according to claim 1, wherein when a beam diameter of the pulse laser incident on the lens is D [mm], fλ/D is set to be 1.4 to 3.5 μm.

### Claim 4 (depends on 1)

The laser ignition device according to claim 1, wherein when a beam diameter of the pulse laser incident on the lens is D [mm], fλ/D is set to be 2.1 to 2.8 μm.