A fuel composition having a boiling range of between 95 to 440 degrees Fahrenheit containing (a) a saturates content below 55 vol %; (b) a RON of from about 88 to about 91; (c) an olefins content of from about 0 to about 5 vol %; (d) an aromatics content of from about 32 to about 40 vol %; (e) an ethanol content of from about 8 to about 16 vol %; (f) an octane sensitivity of from about 8 to about 11; and the fuel composition is used in an HCCI engine.

Some embodiments described herein relate to a method of operating a compression ignition engine. The method of operating the compression ignition engine includes opening an intake valve to draw a volume of air into a combustion chamber, closing an intake valve, and moving a piston from a bottom-dead-center (BDC) position to a top-dead-center (TDC) position in the combustion chamber at a compression ratio of at least about 15:1. The method further includes injecting a volume of fuel into the combustion chamber at an engine crank angle between about 330 degrees and about 365 degrees during a first time period. The fuel has a cetane number less than about 40. The method further includes combusting substantially all of the volume of fuel. In some embodiments, a delay between injecting the volume of fuel into the combustion chamber and initiation of combustion is less than about 2 ms.

Methods and systems are provided for an auto-ignition internal combustion engine comprising an exhaust gas recirculation arrangement, an intake system, and an exhaust gas discharge system for the discharge of exhaust gases, in which the internal combustion engine is operable, at least in a first, stoichiometric operating mode, by way of a spatial ignition method (HCCI mode). For the aftertreatment of the exhaust gas in the first operating mode, a three-way catalytic converter is provided in the exhaust gas discharge system for reducing nitrogen oxides and oxidizing unburned hydrocarbons and carbon monoxide. In this way, the auto-ignition internal combustion engine has a greater window of operation in the HCCI mode than conventional auto-ignition internal combustion engines.

A residual gas ignitor for use in igniting a fuel-air mixture within a main combustion chamber of an engine. The residual gas ignitor includes at least one inlet/outlet port, a residual gas ignitor chamber for receiving a combustion gas from the main combustion chamber, an ignitor valve for opening and closing the at least one inlet/outlet port, an actuator for actuating the ignitor valve to open and close the at least one inlet/outlet port, a valve guide for keeping the ignitor valve in a correct orientation within the residual gas ignitor, a preload spring for being in compression when the actuator disposes the ignitor valve into the closed position, and a heating element for maintaining or increasing a temperature of the combustion gas while the combustion gas is in the residual gas ignitor chamber. The residual gas ignitor may be used in engines for initiating combustion of fuel-air mixtures.

A residual gas ignitor for use in igniting a fuel-air mixture within a main combustion chamber of an engine. The residual gas ignitor includes at least one inlet/outlet port, a residual gas ignitor chamber for receiving a combustion gas from the main combustion chamber, an ignitor valve for opening and closing the at least one inlet/outlet port, an actuator for actuating the ignitor valve to open and close the at least one inlet/outlet port, a valve guide for keeping the ignitor valve in a correct orientation within the residual gas ignitor, a preload spring for being in compression when the actuator disposes the ignitor valve into the closed position, and a heating element for maintaining or increasing a temperature of the combustion gas while the combustion gas is in the residual gas ignitor chamber. The residual gas ignitor may be used in engines for initiating combustion of fuel-air mixtures.

An engine system capable of controlling an intake air flow includes a combustion chamber, an ignition plug, an intake air flow control valve, and a controller. The controller performs, in at least a part of an operating range, SPCCI combustion in which after jump-spark ignition combustion of a portion of a mixture gas inside the combustion chamber by a jump-spark ignition of the ignition plug, compression ignition combustion of the remaining mixture gas is carried out by a self-ignition. The controller strengthens, at least in a part of the operating range of SPCCI combustion, the intake air flow inside the combustion chamber by controlling the intake air flow control valve. The controller controls, in a middle-load range of the operating range where SPCCI combustion is performed, the intake air flow control valve so that the intake air flow becomes weaker than in a high-load range and a low-load range.

An engine system capable of controlling an intake air flow includes a combustion chamber, an ignition plug, an intake air flow control valve, and a controller. The controller performs, in at least a part of an operating range, SPCCI combustion in which after jump-spark ignition combustion of a portion of a mixture gas inside the combustion chamber by a jump-spark ignition of the ignition plug, compression ignition combustion of the remaining mixture gas is carried out by a self-ignition. The controller strengthens, at least in a part of the operating range of SPCCI combustion, the intake air flow inside the combustion chamber by controlling the intake air flow control valve. The controller controls, in a middle-load range of the operating range where SPCCI combustion is performed, the intake air flow control valve so that the intake air flow becomes weaker than in a high-load range and a low-load range.

An engine control apparatus includes an ignition control section and an injection control section. When partial compression ignition combustion is carried out, the ignition control section causes an ignition plug to carry out: main ignition in which a spark is generated in a late period of a compression stroke or an initial period of an expansion stroke to initiate the SI combustion; and preceding ignition in which the spark is generated at earlier timing than the main ignition. Also, when the partial compression ignition combustion is carried out, the injection control section causes the injector to inject fuel at such timing that the fuel exists in a cylinder at an earlier time point than the preceding ignition. Energy of the preceding ignition is set to be higher when an engine speed is high than when the engine speed is low.

Provided is an ignition control section and an injection control section. When partial compression ignition combustion is carried out, the ignition control section causes an ignition plug to carry out: main ignition in which a spark is generated in a late period of a compression stroke or an initial period of an expansion stroke to initiate SI combustion; and preceding ignition in which the spark is generated at earlier timing than the main ignition. Also, when the partial compression ignition combustion is carried out, the injection control section causes an injector to inject fuel at such timing that the fuel exists in a cylinder at an earlier time point than the preceding ignition. Ignition timing of the preceding ignition is set to be more retarded when an in-cylinder pressure specified by an in-cylinder pressure specification section is high than when the in-cylinder pressure is low.

A fuel for an internal combustion engine includes a fatty alkyl ether having a formula corresponding to formula (II): ##STR00001##
wherein x is 1-8, and y is 0 to 3; and the alkyl is an alkyl group having a number of carbon atoms that is less than the number of carbon atoms in the alkyl chain on the opposite side of the oxygen atom. The fatty alky ether can be used as a neat fuel or blend with biodiesel, diesel, ethanol or other fuels. The fatty alkyl ethers are improved in cetane number and cold flow properties over a biodiesel with fatty acid methyl acid methyl ester compounds. This is particularly valuable for compression ignition engines. A method of combustion in several types of engines is also disclosed.