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Photo-ignition Torch (PITCH) - Combustion Initiator/Gas Generator

The Air Force Research Laboratory (AFRL) invention, PITCH, provides a versatile, ultra-compact, self-contained, scalable, optical (non-contact, EMI safe) ignition platform for initiation of secondary chemical reactions such as combustion, detonation, and gas generation for rapid chamber pressurization. PITCH facilitates millisecond (ms) ignition of solid, liquid, and gaseous combustibles at pressures up to 2,000 psi. The AFRL invention takes advantage of the photo-activated ignition property of carbon-based nanostructures induced by exposure to a low-power flash of light, such as a compact camera flash. The carbon nanostructures are encapsulated with a blend of combustible materials (solid fuels/propellant), which may be tailored for specific applications. PITCH provides adjustable parameters for the initiation of combustion or detonation reactions including: main fuel type, ignition speed and duration, and the length of the ignition flame/plume (>15 cm). In addition, for gas generation applications, the amount of the generated gases and their temperature can be controlled.

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The Technology: 

Basic PITCH consists of a low power light source, AA battery or solar cell operated Xenon flash lamp, the driver/control electronics, and an encapsulated photo-activated carbon nanostructure along with the solid fuel mixture. The solid fuel is ignited a few ms after the Xenon flash is activated and the capsule expels a flame/jet of very hot gases and burning debris (>2000oC) into the secondary volume, typically a combustion chamber, in <30 ms.

A video of the technology in action is available for download here.

  • Effective: Establishes distributed ignition within the combustion chamber much more effectively than typical ignition sources
  • Small size, light weight, low power: A small fraction of the size, weight, and power consumption of comparable ignition units
  • Safe: Photo-activated (EMI safe), environmentally robust, shock resistant, with 2-step electronic safe and armed function
  • Self-contained: Battery-operated (single AA), can be deployed in hard to access and tight spaces such as tiny airbags
  • Versatile: Compatible with solid, liquid, and gaseous fuels; operates at pressures from partial vacuum to 2000 psi; very scalable, can be wireless or remote operation with 100+ feet of wire (Fig. 1), the drop in unit (Fig.2) is suitable for retrofits, and new designs
The Opportunity: 

Currently in use by the inventors for ignition stability test of subscale rocket injectors near 500 psi, PITCH is useful for many applications including spacecraft, satellites, missiles, flairs, gas generators, hybrid airbag inflation devices, and relight of different turbines/combustors with near zero delay time.