Mixing controlled compression ignition with methanol: An experimental study of injection and EGR strategy

Abstract

Methanol is a fuel that can be produced using renewable electricity, green hydrogen, and a carbon-neutral carbon source. As a low-carbon liquid fuel, methanol is a leading candidate as a drop-in replacement fuel for rapid decarbonization of the transportation sector. In this work, methanol is tested experimentally in mixing-controlled compression ignition using a single-cylinder research engine. Specifically, the impact of a double injection strategy and high exhaust gas recirculation (EGR) dilution on performance and emissions parameters are studied. As a single-carbon, oxygenated fuel, methanol has a near-zero sooting potential, meaning there is no soot-NOx tradeoff as EGR dilution is increased. EGR dilution effectively reduces NOx emissions without a significant combustion efficiency or thermal efficiency penalty until the global equivalence ratio exceeds 0.9, at which point, a significant combustion efficiency penalty is incurred in the form of increased CO emissions. If stoichiometric operation with high EGR dilution is considered, engine-out NOx emissions are low, even at very high loads, and NOx aftertreatment is simplified through the use of a three-way catalyst. However, a relative decrease in the net fuel conversion efficiency of up to 8.5% was observed, demonstrating an emissions-efficiency tradeoff. Under lean and stoichiometric conditions, no appreciable agglomeration of particulate matter was observed.

Study on methanol-hydrogen engine in extended-range electric vehicles

“…The ECU used in the experiment was manufactured by BOSCH, model ME788. The Methanol flow control unit (13) controlled the flow of methanol into the methanol dissociating device (1) based on engine information provided by ECU (14).…”

“…Methanol, with a hydrogen mass fraction of 12.5%, is also considered a promising liquid hydrogen carrier due to its ability to conveniently and efficiently produce hydrogen through methods such as dissociating or reforming. 13 Hydrogen has a very high flame speed. 14 Adding hydrogen to the engine can shorten the flame development period, leading to earlier heat release.…”

Renewable Methanol as a Fuel for Heavy-Duty Engines: A Review of Technologies Enabling Single-Fuel Solutions

“…Gainey et al [93] conducted experiments with methanol CI utilizing EGR on a 0.423 L single-cylinder research engine at medium to high loads, employing a standard diesel CR of 16. Their findings indicated a decrease in engine-out NO x emissions with increasing EGR, accompanied by an elongation of the heat release and a slight reduction in efficiency.…”

“…One possibility is employing a pilot injection alongside a larger main injection to spread out the cooling effect induced by methanol injection while utilizing the pilot as a means to preheat the combustion chamber, thereby facilitating the ignition of the main injection. Gainey et al [93] demonstrated that advancing both the pilot and main injections could positively influence efficiency, provided that excessive fuel does not combust before TDC. Additionally, they highlighted the significance of pilot size, emphasizing that an insufficiently sized pilot might fail to adequately assist the main injection in ignition.…”