142 results about "Autoignition temperature" patented technology

A combustor method and apparatus is provided. The method utilizes flameless combustion with one or more of three improvements to enhance ignition of the flameless combustor. A catalytic surface can be provided within a combustion chamber to provide flameless combustion at least in the vicinity of the catalytic surface at a temperature that is much lower than the autoignition temperature of fuel in air without the presence of the catalytic surface. Nitrous oxide or supplemental oxygen may also be used as an oxidant either instead of air or with air to reduce ignition temperatures. Further, electrical energy can be passed through the fuel conduit, raising the temperature of the conduit to a temperature above which the fuel will ignite when combined with the oxidant.

A process heater is provided utilizing flameless combustion, the process heater having: an oxidation reaction chamber, the oxidation reaction chamber having an inlet for oxidant, an outlet for combustion products, and a flow path between the inlet and the outlet; a fuel conduit capable of transporting a fuel mixture to a plurality of fuel nozzles within the oxidation reaction chamber, each nozzle providing communication from within the fuel conduit to the oxidation chamber, with each nozzle along the flowpath between the inlet and the outlet; a preheater in communication with the oxidation chamber inlet, the preheater capable of increasing the temperature of the oxidant to a temperature resulting in the combined oxidant and fuel from the fuel nozzle closest to the oxidation chamber inlet being greater than the autoignition temperature of the combined oxidant and fuel from the fuel nozzle closest to the oxidation chamber inlet; and a process chamber in a heat exchange relationship to the oxidation reaction chamber wherein the heat transferred from the oxidation section does not causes the temperature of the mixture within the oxidation reaction chamber in the vicinity of each fuel nozzle to decrease below the auto ignition temperature of the combined mixture in the oxidation chamber in the vicinity of that fuel nozzle.

A liquid primary fuel is ignited by HCCI with the assistance of the early injection of a liquid pilot fuel. Pilot fuel injection and/or ignition are preferably controlled so as to permit the injected pilot fuel to become thoroughly distributed through and mixed with the primary fuel/air charge in the combustion chamber and vaporized prior to ignition. Pilot fuel having a lower autoignition temperature will be ignited by compression ignition, followed by the ignition of the homogeneous mixture of the primary fuel and air. HCCI combustion of the primary fuel is facilitated by 1) selection of the properties of the primary and pilot fuels and 2) obtaining a homogenous mixture of primary fuel and air by injecting primary fuel into the engine's intake air stream in the form of finely atomized droplets having a mean diameter in the micron range.

A method of operating an internal combustion engine having a combustion chamber with a piston and a spark plug, comprising during a first mode, bringing the temperature of the combustion chamber to auto-ignition temperature by adjusting engine operating conditions and producing auto-ignition in said combustion chamber without requiring spark from said spark plug; and during a second mode, bringing the temperature of the combustion chamber close to auto-ignition temperature by adjusting engine operating conditions, forming a small cloud of stratified air-fuel mixture near said spark plug, igniting said fuel cloud by a spark form said spark plug, and then causing cylinder pressure to rise, thereby producing auto-ignition at other sites in said combustion chamber wherein said first mode is implemented in a first operating range and said second mode is implemented only in a second operating range where engine speed and load are lower than said first operating range.

A method of operating an internal combustion engine having a combustion chamber with a piston, comprising: inducting at least air and fuel vapors from a fuel vapor system; and adjusting an operating condition of the engine so that a mixture of air and fuel in the combustion chamber, including said fuel vapor, approaches, but does not achieve, said autoignition temperature; and performing a spark from the spark plug so that said mixture substantially auto-ignites.

An apparatus and method for igniting a gaseous fuel directly introduced into a combustion chamber of an internal combustion engine comprises steps of heating a space near a fuel injector nozzle; introducing a pilot amount of the gaseous fuel in the combustion chamber during a first stage injection event; controlling residency of the pilot amount in the space such that a temperature of the pilot amount increases to an auto-ignition temperature of the gaseous fuel whereby ignition occurs; introducing a main amount of the gaseous fuel during a second stage injection event after the first stage injection event; and using heat from combustion of the pilot amount to ignite the main amount.

In one embodiment, a total pilot injection amount is calculated from the difference between a compressed gas temperature in a cylinder and a fuel self-ignition temperature. As pilot injection, a plurality of instances of divided pilot injection are performed, and by setting the injection amount per one instance of divided pilot injection to an injector minimum limit injection amount, each divided pilot injection amount is suppressed, and the penetration of fuel is suppressed to a low level so that attachment of fuel to a wall face is avoided, and also, fuel is caused to accumulate in the center portion of the cylinder.

Mixtures of high explosives with materials that readily absorb microwaves ignite more readily when exposed to microwave energy than the corresponding neat explosives. A charge of HMX (0.5 gram) mixed with carbon nanotubes (1 percent by mass) ignited with 7.5 joules at an average rate of 750 W for 10 milliseconds. To raise a charge of the same mass of neat HMX to an autoignition temperature of 200 degrees Celsius would require much more energy (about 110 joules) for a longer duration (about 150 milliseconds).

A fuel management system mounted on a vehicle is operative to feed individually or a mixture of grades of relatively low, intermediate, and high autoignition temperature fuels to an associated internal combustion engine. The system includes an on board separation unit (OBS unit) for receiving and separating intermediate autoignition temperature (IAT) fuel into low and high autoignition temperature fuels, LAT and HAT, respectively. The production rate of the LAT and HAT fuels by the OBS unit is controlled to substantially match the consumption requirements of the engine at any given time for the LAT and HAT fuels.

A method of operating an internal combustion engine having a combustion chamber with a piston and a spark plug, when transitioning between spark ignition combustion and autoignition combustion, creating a first mixture of air and fuel, adjusting an operating condition of the engine so that said first mixture of air and fuel in the combustion chamber approaches, but does not achieve, the autoignition temperature, and performing a spark from the spark plug so that at least a portion of said first mixture combusts to raise a remaining portion of said first mixture to said autoignition temperature.

A method of operating an internal combustion engine having a combustion chamber with a piston is disclosed. The method comprising during a first mode, adjusting an operating condition of the engine so that a first mixture of air and fuel in the combustion chamber attains an autoignition temperature and therefore combusts without performing a spark from the spark plug; and during a second mode, adjusting said operating condition of the engine so that a second mixture of air and fuel in the combustion chamber approaches, but does not achieve, said autoignition temperature; and performing a spark from the spark plug after top dead center of piston position so that said second mixture combusts.

A method of operating an internal combustion engine having a combustion chamber with a piston, comprising of adjusting an operating parameter of the engine so that a mixture of air and fuel in the combustion chamber approaches, but does not achieve, an autoignition temperature, and performing a spark from the spark plug so that said second mixture combusts; adjusting a timing of said spark from the spark plug; and adjusting an operating parameter to increase a correlation between said adjusted spark timing and timing of said combustion.

Described herein are embodiments of systems and methods for oxidizing gases. In some embodiments, a reaction chamber is configured to receive a fuel gas and maintain the gas at a temperature within the reaction chamber that is above an autoignition temperature of the gas. The reaction chamber may also be configured to maintain a reaction temperature within the reaction chamber below a flameout temperature. In some embodiments, heat and product gases from the oxidation process can be used, for example, to drive a turbine, reciprocating engine, and injected back into the reaction chamber.

In a method for the combustion of a fuel, a fuel or a premixed combustible mixture is introduced into a combustion space as a combustible fluid open jet. The velocity of the open jet is selected in such a way that it is impossible for a stable flame front to form, i.e. is in any event greater than the flame front velocity, and that, on account of a jet pump effect, flue gas is mixed into the combustible fluid jet from the combustion chamber in a jet-induced recirculation internally within the combustion chamber. The admixed flue gas dilutes and heats the combustible fluid. The heating causes the spontaneous ignition temperature to be exceeded, and a low-pollutant volumetric flame is formed in a highly dilute atmosphere.

Embodiments of the present invention provide a fuel supply system for combustion engines, whereby the temperatures of an oxidizer and fuel may be increased so that the temperatures approach but do not achieve an auto-ignition temperature for the fuel charge. The fuel charge may result in substantial improvements in fuel efficiency.