A vehicular propulsion system, a vehicular fuel system and a method of operating an internal combustion engine. A separation unit that makes up a part of the fuel system may selectively receive and separate at least a portion of onboard fuel and a flowable adsorbent in order to separate the fuel into octane-enhanced and cetane-enhanced fuel components. A controller may be used to determine a particular operating condition of the internal combustion engine such that the onboard fuel can be sent to one or more combustion chambers within the internal combustion engine without first passing through the separation unit during one operating condition, or instead to the separation unit in situations where the internal combustion engine may require an octane-rich or cetane-rich mixture in another operating condition.

A vehicular propulsion system, a vehicular fuel system and a method of producing fuel for an internal combustion engine. A separation unit that makes up a part of the fuel system includes one or more adsorbent-based reaction chambers to selectively receive and separate at least a portion of onboard fuel into octane-enhanced and cetane-enhanced components. Regeneration of an adsorbate takes place through interaction with a solvent, while subsequent separation allows the solvent to be reused. A controller may be used to determine a particular operational condition of the internal combustion engine such that the onboard fuel can be sent to one or more combustion chambers within the internal combustion engine without first passing through the separation unit, or instead to the separation unit in situations where the internal combustion engine may require an octane-rich or cetane-rich mixture.

Methods and systems for starting and stopping a diesel engine are presented. In one example, a cetane enhancer is selectively mixed with diesel fuel to provide a cetane enhanced diesel fuel. A diesel engine may be supplied the cetane enhanced diesel fuel after an engine cold start to improve catalyst light off time and engine emissions.

Methods and systems for operating an engine with different fuels having different cetane levels are described. In one example, start of fuel injection timing for engine cylinders may be adjusted responsive to engine deceleration or combustion phase during engine cranking. The start of fuel injection timing may be retarded for higher cetane fuels and advanced for lower cetane fuels.

Methods and systems are provided for accurately determining the composition of a knock control fluid using sensors already present in the engine system. An intake or an exhaust oxygen sensor is used to estimate the water and the alcohol content of a knock control fluid that is direct injected into an engine cylinder responsive to an indication of abnormal combustion. A change in the pumping current of the oxygen sensor due to the water content of the knock control fluid is distinguished from a change in the pumping current of the oxygen sensor due to the alcohol content of the knock control fluid.

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 application is directed to systems and methods for on-board fuel separation. The system includes: a source fuel tank for liquid fuel; a pump; and a membrane module. The membrane module includes a hydrophilic membrane, a retentate channel, and a permeate channel. The retentate and permeate channels are on opposing sides of the membrane. The membrane module receives fuel from the source fuel tank and separates the liquid fuel into a high octane fraction that collects in the retentate channel and a low octane fraction that diffuses through the membrane to the permeate channel. The system further includes a low octane fuel tank for receiving at least a portion of the low octane fraction, a high octane fuel tank for receiving at least a portion of the high octane fraction, and an engine configured to selectively receive at least a portion of the low and high octane fractions.

A vehicular propulsion system, a vehicular fuel system and a method of operating an internal combustion engine. A separation unit that makes up a part of the fuel system includes one or more adsorbent-based chambers such that the separation unit may selectively receive and separate at least a portion of onboard fuel into octane-enhanced and cetane-enhanced fuel components. A supply tank includes three compartments where the first contains the onboard fuel, the second receives a vaporized adsorbate from the separation unit and condenses at least a part of it into one of an octane-rich fuel component or a cetane-rich fuel component, while the third may either store the condensed and enriched fuel component or help condense more of the vaporized adsorbate. The condensing takes place through heat exchange between the onboard fuel and the vaporized adsorbate that are present within the various compartments of the supply tank. A controller may be used to determine a particular operational condition of the internal combustion engine such that the onboard fuel can be sent to one or more combustion chambers within the internal combustion engine without first passing through the separation unit, or instead to the separation unit in situations where the internal combustion engine may require an octane-rich or cetane-rich mixture.

The present disclosure relates to a miniaturized fuel laboratory system having exterior dimensions enabling the system to be at least one of hand-holdable or contained on a component. The system makes use of a processor, a fuel inlet port for receiving a quantity of fuel to be used as a fuel test sample, and at least one fuel sensor in communication with the fuel inlet port for receiving the fuel test sample. The processor uses the information obtained by the fuel sensor to determine at least one characteristic of the fuel test sample.

Methods and systems for starting and stopping a diesel engine are presented. In one example, a cetane enhancer is selectively mixed with diesel fuel to provide a cetane enhanced diesel fuel. A diesel engine may be supplied the cetane enhanced diesel fuel after an engine cold start to improve catalyst light off time and engine emissions.