Abstract: Methods and systems for utilizing heated fuel to compensate for a low cetane number, cetane number variance and sub-optimal engine cold-start performance in internal combustion engines are disclosed herein. Systems comprise a heater, a sensor, and an engine control unit (“ECU”). Methods can comprise detecting variables that affect combustion, calculating conditions inside a combustion chamber, determining the difference between current ignition delay and a desired ignition delay, estimating a cetane number of a fuel, and using the data to determine a suitable temperature that will compensate for cetane number and improve the ignition delay. Other methods comprise sending a signal to a heater in communication with a fuel injection system such that said heater warms fuel within the fuel injection system prior to injecting the fuel into a combustion chamber.

Abstract: An exhaust gas recirculation (EGR) system is employed in a supercritically fueled direct-injection compression ignition engine system. The EGR system may include multiple stages, where a portion of exhaust gas is diverted from upstream of a turbine of a turbocharger and a second portion is diverted from downstream of the turbine.