Abstract
Notwithstanding the policies that move towards electrified powertrains, the transportation sector mainly employs internal combustion engines as the primary propulsion system. In this regard, for medium- to heavy-duty applications, as well as for on- and off-road applications, diesel engines are preferred because of the better efficiency, lower CO2, and greater robustness compared to spark-ignition engines. Due to its use at a large scale, the internal combustion engines as a source of energy depletion and pollutant emissions must further improved. In this sense, the adoption of alternative combustion concepts using cleaner fuels than diesel (e.g., natural gas, ethanol and methanol) presents a viable solution for improving the efficiency and emissions of the future powertrains. Particularly, the methane–diesel dual-fuel concept represents a possible solution for compression ignition engines because the use of the low-carbon methane fuel, a main constituent of natural gas, as primary fuel significantly reduces the CO2 emissions compared to conventional liquid fuels. Nonetheless, other issues concerning higher total hydrocarbon (THC) and CO emissions, mainly at low load conditions, are found. To minimize this issue, this research paper evaluates, through a new and alternative approach, the effects of different engine control parameters, such as rail pressure, pilot quantity, start of injection and premixed ratio in terms of efficiency and emissions, and compared to the conventional diesel combustion mode. Indeed, for a deeper understanding of the results, a 1-Dimensional spray model is used to model the air-fuel mixing phenomenon in response to the variations of the calibration parameters that condition the subsequent dual-fuel combustion evolution. Specific variation settings, in terms of premixed ratio, injection pressure, pilot quantity and combustion phasing are proposed for further efficiency improvements.
Highlights
The higher efficiency of the compression ignition (CI) engines compared to the spark ignition (SI)engines justifies the spread of this propulsion system in the transport sector
Regarding the emissions, CI engines operating under conventional diesel combustion (CDC) are characterized by the well-known NOx-soot trade-off, which imposes the manufacturers to couple the vehicle with complex aftertreatment systems (ATS)—diesel oxidation catalyst, diesel particulate filter and selective catalytic reduction—to meet the severe pollutant emission standards imposed by the legislation [1]
Three levels of pilot quantity injection were studied with a fixed premixed ratio of 50%
Summary
The higher efficiency of the compression ignition (CI) engines compared to the spark ignition (SI)engines justifies the spread of this propulsion system in the transport sector. The higher efficiency of the compression ignition (CI) engines compared to the spark ignition (SI). Energies 2020, 13, 3734 urea, etc.), at the expense of CO2 , in comparison to SI engines [2] For these reasons, in the field of internal combustion engines (ICE), there is an important interest in studying and applying advanced combustion concepts [3,4,5] and specific fuels to face the issues encountered with the conventional technologies [6,7]. The PPC concept, applied to ICEs, is prospectively able to simultaneously reduce the NOx and soot emissions, shorten the combustion duration and reduce heat transfer losses inside the cylinder as compared to CDC [8,9]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
