Rahul Ganti

Laser Ignition • An alternate way to ignite the air fuel mixture • Starts with stimulus of a laser light source • Short but powerful flash • No durable components Pros • No erosion (durability) • No heat sink (quenching) • Flexibility in determining the ignition site • Less disturbance of the flow-field • Low "wall-plug" efficiency • High pressure requires lower energy for breakdown • Faster time scale (finer control ignition timing) • Improves lean burn performance in NG engines ( extension = 0.15 – 0.3, up to l = 1.8-1.9 ) Cons • Cost of technology • Size of the laser • Energy can be wasted before the beam reaches the focal point Market & Challenges Laser Ignition Market • Mazda RX-9 and GM V-8 engines could soon be powered by lasers as • Still experimental, not yet commercialized Technical Challenges • Not so far behind but still far enough. • The devices are too big, too expensive and still have a point ignition. • The laser energy is transmitted through free space and into an optical plug, energy in the form of photons is wasted before the beam reach the focal point. • The efficiency of energy transfer to near-threshold laser sparks is substantially lower than to electrical sparks, so more power is required to heat laser sparks. • Volume of a typical electrical ignition spark is 10^-3 cm3 while that for laser ignition is 10^-5.Hence charge is less. • The researchers are confident that the fiber-optic laser cables' technical challenges will soon be overcome. • Japanese researchers have created a laser system small enough to fit into an engine cylinder head. • Federal Mogul still considering options like micro waves and Corona* Patents 6796278 Method for using lasers to ignite air fuel mixture in, multiple, customizable, locations 7741762 Pre ignition chamber to control ignition process and flame front 7741762 Laser Ignition Methods and apparatuses for laser ignited engines The invention involves incorporation of a laser ignition system in any type of spark-ignition engine, including a direct-injection engine. The laser ignition system includes a pulsed laser of sufficient energy (e.g., 100 mJ/pulse or more in one embodiment) to create a discharge at the focal point of the focused laser beam. The system also includes a window and window holder to allow optical access into the combustion chamber for the laser pulse, and adaptive optics that allow adjustment of the location of the beam focal point within the combustion chamber. The laser ignition system may be combined with an engine configuration in which the fuel is injected directly into the combustion chamber. Several different combustion chamber configurations are possible. 7741762 Laser Ignition Dual-spark pre-chambered spark igniter A spark igniter for an engine having at least one engine cylinder, comprising: a spark plug body; a first electrode, extending a first distance from the top of the spark plug body; a second electrode, spaced from the first electrode and extending from the top of the spark body a second distance, which is greater than that of the first electrode; a ground strap connected to electrical ground, and having a spark gap from the second electrode; And a precombustion chamber enclosing the first electrode and the second electrode, the chamber having a bottom end and having a top end with at least one orifice in fluid communication with the at least one engine cylinder; wherein the spark end of the first electrode is closer to the bottom end of the precombustion chamber than the spark end of the second electrode, and the spark end of the second electrode is closer to the top end of the precombustion chamber than the spark end of the first electrode. Laser Ignition Laser car ignition systems promise better fuel efficiency and lower pollution than conventional ones. As calls for improved energy efficiency and reduced auto emissions grow ever louder, lasers are being investigated as possible replacements for the conventional spark plug.