1D Simulation and Experimental Analysis on the Effects of the Injection Parameters in Methane–Diesel Dual-Fuel Combustion

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.

Specific and Cumulative Exhaust Gas Emissions in Micro-Scale Generators Fueled by Syngas from Biomass Gasification

“…The next step would be to measure the engine airflow in order to assess the fuel/air ratio that guarantees the best performances and evaluate it at different electrical power outputs as well as analyze the in-cylinder pressure for a better understanding of the combustion process [45].…”

The Effects of Ultra-Low Viscosity Engine Oil on Mechanical Efficiency and Fuel Economy

“…After multiple machining processes, the surface of sliding bearing pair cannot be completely smooth and the dynamic pressure oil film thickness is so small under heavy load conditions and even reaches the order of roughness (several microns), that the rough contact of rough surface cannot be ignored. The contact pressure between rough peaks can be calculated by Greenwood/Tripp model [8]: The comparison of viscosity temperature relationship between SAE 15W40 and SAE 0W20 standard oil depicts in Figure 5, using data from the standard oil database in AVL Excite software.…”

“…Since most of the friction losses in the ICE occur at the cylinder inner surface with piston and piston ring mating and crankshaft bearing friction, the exploration of friction reduction for these sliding friction pairs is mainly in the areas of lubrication additives, application of advanced coating and surface technologies, precise lubrication theory and simulation techniques. Other works performed an overview of the combustion technologies that have been tested able to improve the CO 2 and the NOx-Soot trade-offs such as specific bowl design, innovative fuel injection systems [7][8][9][10] and clean combustion technologies [11,12]. Studies have shown that reducing oil viscosity can be effective in improving fuel efficiency, but the problem that accompanies the application of lower viscosity oils is the accentuation of wear problems caused by the inadequate lubrication carrying capacity of lower viscosity oils [13].…”

Combustion Thermodynamics of Ethanol, n-Heptane, and n-Butanol in a Rapid Compression Machine with a Dual Direct Injection (DDI) Supply System

“…Multiparameter research results on methane and diesel fuel combustion were analyzed in [8]. In that paper, the effects of the premixed ratio, injection pressure, and fuel doses in relation to the engine efficiency were assessed.…”