Investigation on the Effect of Port-Injected Methanol on the Performance and Emissions of a Diesel Engine at Different Engine Speeds

Abstract

This study is aimed at investigating the effect of port-injected methanol on the performance and emissions of a diesel engine under different engine loads and engine speeds. Experiments were performed on a fourcylinder diesel engine operating at three engine speeds and five engine loads for each speed. The results show that when methanol is injected into the intake port of the diesel engine, the brake thermal efficiency decreases at low engine loads but has no significant change at medium to high engine loads. There is also a reduction of NO x and particulates but a significant increase in CO, HC, NO 2 , unburned methanol, and formaldehyde emissions. The application of port-injected methanol shows potential greenhouse benefits only at high engine loads with a high level of fumigation methanol. With a diesel oxidation catalyst, the HC, CO, unburned methanol, and formaldehyde emissions are significantly reduced when the exhaust gas temperature is sufficiently high. The results are consistent at each engine speed.

Feasibility of using less viscous and lower cetane (LVLC) fuels in a diesel engine: A review

“…Contrary to fumigation of methanol with diesel, a noticeable increase in NO X and particulate emissions were noted for biodiesel operation with fumigated methanol, while the emissions of CO and HC were increased. Therefore, in order to control the emission of HC and CO, they used DOC while fumigating methanol in their next experimental investigation [191]. In addition to regulated emission, they also extended their study to measure unregulated emission and reported the effect of DOC on both regulated and unregulated emissions.…”

Renewable Methanol with Ignition Improver Additive for Diesel Engines

“…For example, NO 2 concentration increased from 9 to 40 ppm when manifold injection was applied, whereas NO x concentrations were 124 and 130 ppm, respectively. In the fumigation concept, increased NO 2 concentrations were also observed by Cheung et al The manifold injection system could further be developed in both flow design and main injection functionality to investigate the potential of the concept.…”

Methanol as a fuel for internal combustion engines

“…This is thought to be due to the formation of the HO 2 radical during methanol combustion, which reacts with NO to NO 2 through N O + HO 2 → N O 2 +OH. The NO 2 to NO ratio has been found to increase sixfold for some cases, compared to diesel operation [209]. However, the ratio was found to significantly decrease when using a diesel oxidation catalyst [211].…”

“…In most cases the conversion of the base diesel engine to dual fuel operation with methanol is targeted at decreasing the two main pollutants of concern for diesel engines: NO X and PM. Reviewing the reported results, Coulier and Verhelst concluded that dual fuel operation indeed leads to a general drop in NO X emissions across the load and speed range, ranging from a 6% [209] reduction to over 50% [210] depending on load and achievable methanol fraction. This reduction gets more pronounced as the substitution ratio is increased.…”

“…Very few data can be found on formaldehyde emissions in dual fuel operation. Cheung et al [209] measured formaldehyde emissions for dual fuel operation with low methanol substitution ratios (up to 30% on an energy basis) and found them to increase with load and methanol fraction, up to 3.3 times higher than for pure diesel operation. They explain the increased emissions by the lower combustion temperature, although this contradicts the increase with load.…”