Methods and systems are described for combustion engine mode optimization. The system includes a combustion engine, a fuel delivery system, and a controller communicatively coupled to the combustion engine and the fuel delivery system. The controller selects a low temperature combustion mode based on the combustion engine being warmer than a predetermined temperature and low load conditions on the combustion engine. The low temperature combustion mode includes instructions that reduces an intake valve opening duration and an exhaust valve opening duration. The controller reduces the intake valve opening duration and the exhaust valve opening duration to create a delay between an intake valve opening duration and an exhaust valve opening duration in response to selecting the low temperature combustion mode. The delay increases a residual gas temperature in the combustion chamber and induces auto-ignition of fuel in the combustion chamber.

A torch igniter system for a combustor of a gas turbine engine includes a housing defining a combustion chamber, an ignition source disposed at least partially in the combustion chamber, a fuel injector, a first fluid path connecting a first fuel source to the fuel injector, a second fluid path connecting an air source to the fuel injector, and a third fluid path connecting a second fuel source to the combustion chamber. The fuel injector is configured to inject fuel, air, or a mixture of fuel and air into the combustion chamber and to impinge on the ignition source.

A torch igniter system for a combustor of a gas turbine engine includes a housing defining a combustion chamber, an ignition source disposed at least partially in the combustion chamber, a fuel injector, a first fluid path connecting a first fuel source to the fuel injector, a second fluid path connecting an air source to the fuel injector, and a third fluid path connecting a second fuel source to the combustion chamber. The fuel injector is configured to inject fuel, air, or a mixture of fuel and air into the combustion chamber and to impinge on the ignition source.

Embodiments disclosed herein relate generally to systems and methods of operating internal combustion (IC) engines, and more specifically to systems and methods of starting compression ignition (CI) engines when the surrounding environment is significantly colder than the normal operating temperature of the engine (i.e., cold-starting). In some embodiments, the CI engine can include an ignition-assist device. In some embodiments, a method of operating a CI engine during cold-start can include opening an intake valve to draw a volume of air into the combustion chamber, moving a piston from a bottom-dead-center position to a top-dead-center position in a combustion chamber at a compression ratio of between about 15 and about 25, injecting a volume of fuel, the fuel having a cetane number of less than about 30, closing the intake valve, and combusting substantially all of the volume of fuel.

Embodiments disclosed herein relate generally to systems and methods of operating internal combustion (IC) engines, and more specifically to systems and methods of starting compression ignition (CI) engines when the surrounding environment is significantly colder than the normal operating temperature of the engine (i.e., cold-starting). In some embodiments, the CI engine can include an ignition-assist device. In some embodiments, a method of operating a CI engine during cold-start can include opening an intake valve to draw a volume of air into the combustion chamber, moving a piston from a bottom-dead-center position to a top-dead-center position in a combustion chamber at a compression ratio of between about 15 and about 25, injecting a volume of fuel, the fuel having a cetane number of less than about 30, closing the intake valve, and combusting substantially all of the volume of fuel.

An engine control method includes: a first fuel supply step of supplying fuel into the combustion chamber using an injector when a spark plug makes flame in the combustion chamber so that an air-fuel mixture is generated at least around the spark plug, the air-fuel mixture having an air-fuel mass ratio A/F or a gas-fuel mass ratio G/F, in which gas includes air, higher than a stoichiometric air-fuel ratio; after the first fuel supply step, an ignition step of making the flame in the combustion chamber in the compression stroke using the spark plug; and after the ignition step, a second fuel supply step of supplying the fuel into the combustion chamber in the compression stroke using the injector to increase a fuel concentration of the air-fuel mixture in the combustion chamber.

An engine control method includes: a first fuel supply step of supplying fuel into the combustion chamber using an injector when a spark plug makes flame in the combustion chamber so that an air-fuel mixture is generated at least around the spark plug, the air-fuel mixture having an air-fuel mass ratio A/F or a gas-fuel mass ratio G/F, in which gas includes air, higher than a stoichiometric air-fuel ratio; after the first fuel supply step, an ignition step of making the flame in the combustion chamber in the compression stroke using the spark plug; and after the ignition step, a second fuel supply step of supplying the fuel into the combustion chamber in the compression stroke using the injector to increase a fuel concentration of the air-fuel mixture in the combustion chamber.

An internal combustion engine includes a fuel nozzle for injecting a fuel into a combustion chamber, and a plasma igniter for generating one or more pluralities of free radicals within the chamber, and initiating a flame to ignite the fuel. The igniter protrudes into the chamber. A method of igniting a fuel within a combustion chamber and controlling combustion phasing includes injecting a first portion of the fuel into the combustion chamber, energizing the plasma igniter to generate one or more pluralities of free radicals, each plurality having a known voltage, subsequently injecting a second portion of the fuel into the combustion chamber, and closely coupling activation of the plasma igniter with the second injection to ignite the fuel. Combustion phasing of the ignition event is controlled by controlling the number and voltage of the pluralities of free radicals generated by the plasma igniter.

An internal combustion engine includes a fuel nozzle for injecting a fuel into a combustion chamber, and a plasma igniter for generating one or more pluralities of free radicals within the chamber, and initiating a flame to ignite the fuel. The igniter protrudes into the chamber. A method of igniting a fuel within a combustion chamber and controlling combustion phasing includes injecting a first portion of the fuel into the combustion chamber, energizing the plasma igniter to generate one or more pluralities of free radicals, each plurality having a known voltage, subsequently injecting a second portion of the fuel into the combustion chamber, and closely coupling activation of the plasma igniter with the second injection to ignite the fuel. Combustion phasing of the ignition event is controlled by controlling the number and voltage of the pluralities of free radicals generated by the plasma igniter.

Embodiments described herein relate to systems and methods of operating internal combustion (IC) engines by combusting various fuel chemistries therein. Specifically, engines described herein can operate a wide range of fuel chemistries with varying molecular formulas. The chemical compositions of the fuels described herein make them more difficult to ignite than long chain hydrocarbons (i.e., fuels that include 6 or more carbon atoms in a molecule). In some embodiments, engines described herein can combust fuels that have the chemical properties of alcohols. In some embodiments, engines described herein can combust fuels that include hydroxide groups. Examples of such fuels include methanol and/or ethanol. In some embodiments, engines described herein can combust natural gas. These fuel chemistries are difficult to ignite, particularly at low temperatures and during initial engine startup. Systems and methods described herein address these ignition difficulties, particularly in diesel engine architectures.