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.

A fuel supply apparatus includes a material fuel tank, a separator, a condenser, a first fuel tank, and a first storage device. The material fuel tank is to store a material fuel. The separator is to separate the material fuel supplied from the material fuel tank into a first fuel and a second fuel. The condenser is to condense the first fuel supplied from the separator through a primary-order recovery passage. The first fuel tank is to store the first fuel supplied from the condenser through a secondary-order recovery passage. The first storage device is provided in the secondary-order recovery passage to temporarily store the first fuel supplied from the condenser.

A method of determining the cetane number of a fuel in an internal combustion engine comprising, during running of the engine, i) with respect to one cylinder, performing a routine including a series of injections such that for each injection a quantity of fuel is injected into the cylinder, and during the routine varying the angle at which the injections takes place with respect to crankshaft angle; ii) measuring engine speed at intervals during the series of injections and determining values for changes in engine speed consequent to the injections; iii) determining cetane number from a pre-stored relationship relating the cetane number to changes in engine speed consequent to changes in the test injection angle.

Techniques for separating a fuel on-board a vehicle include mixing an input fuel stream and a fluid solvent; separating the mixture into a first liquid fuel stream and a second liquid fuel stream, the first liquid fuel stream including a first portion of the input fuel stream defined by a first auto-ignition characteristic value and the fluid solvent, the second liquid fuel stream including a second portion of the input fuel stream defined by a second auto-ignition characteristic value that is different than the first auto-ignition characteristic value; separating the first liquid fuel stream into the fluid solvent and the first portion of the input fuel stream; directing the first portion of the input fuel stream to a first fuel tank on the vehicle; and directing the second portion of the input fuel stream to a second fuel tank on the vehicle.

Methods and systems are provided for synergizing the benefits of an electric fuel separator in a hybrid vehicle system. A vehicle controller may hold the engine in a narrow operating range where usage of a selected higher octane or lower octane fuel fraction is optimal while using motor and/or CVT adjustments to address transients generated as driver demand varies. The controller may also adjust a fuel separator speed/pressure opportunistically during regenerative braking to maximize electrical usage as well as at low load conditions to enable extended engine operation in a more fuel efficient load region.

A control apparatus for an internal combustion engine, includes circuitry. The circuitry is configured to control a ratio of an amount of low octane number fuel to be supplied to a cylinder to a total amount of the low octane number fuel and a high octane number fuel to be supplied to the cylinder in order to control an overall octane number of fuel to be supplied to the cylinder. The high octane number fuel has a second octane number higher than a first octane number of the low octane number fuel. The circuitry is configured to calculate a maximum octane number of the fuel to be supplied into the cylinder. The circuitry is configured to restrict a power generated by the internal combustion engine based on the maximum octane number.

A fuel separation system includes a fuel separator configured to receive a fuel stream and separate the fuel stream, based on a volatility of the fuel stream, into a vapor stream defined by a first auto-ignition characteristic value and a first liquid stream defined by a second auto-ignition characteristic value, the second auto-ignition characteristic value greater than the first auto-ignition characteristic value; and a control system communicably coupled to the fuel separator and operable to receive an input from an engine, the input including an engine operating condition, the control system configured to adjust an operating parameter of the fuel separator, based at least in part on the engine operating condition, to vary at least one of the first or second auto-ignition characteristic values.

A fuel separation system includes a fuel separator configured to receive a fuel stream and separate the fuel stream, based on a volatility of the fuel stream, into a vapor stream defined by a first auto-ignition characteristic value and a first liquid stream defined by a second auto-ignition characteristic value, the second auto-ignition characteristic value greater than the first auto-ignition characteristic value; and a heat exchanger fluidly coupled between a fuel input of the fuel stream and the fuel separator, the heat exchanger configured to transfer heat from the vapor stream to the fuel stream, and output a heated fuel stream to the fuel separator and a second liquid stream defined by the first auto-ignition characteristic value.

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.

The present invention relates to fuel systems for diesel engines. In particular, the invention relates to a dual fuel supply system (10) for a diesel engine having an indirect-injection system (12). The invention extends to a diesel engine incorporating the dual fuel supply system (10) and to a vehicle that incorporates a diesel engine having the dual fuel supply system (10). The dual-fuel supply system (10) includes a mixed fuel supply system (17) that includes a first stage (14) having a diesel tank (42) and LPG tank (44), and as second stage (16) to supply the fuel mixture to the injection system (12). The dual-fuel supply system (10) also includes diesel supply system (80) for delivering diesel to the injection system (12). Moreover, the dual fuel system (10) is configured to permit selective change over between the diesel supply system (80) and the mixed fuel system (17) to supply the injection system (12) selectively with either diesel or liquid fuel mixture respectively.