Exhaust Emissions and Combustion Characteristics of a Direct Injection (DI) Diesel Engine Fueled with Methanol−Diesel Fuel Blends at Different Injection Timings

Abstract

In the recent years, environmental concerns and depletion in petroleum resources have forced researchers to concentrate on finding renewable alternatives to conventional petroleum fuels. Therefore, alcohols as renewable and alternative energy sources for the diesel engines gain importance. For this reason, in this study, the performance, exhaust emissions, and combustion characteristics of a single cylinder diesel engine have been experimentally investigated under different injection timings when methanol-blended diesel fuel was used from 0 to 15%, with an increment of 5%. The tests were conducted at three different injection timings (15°, 20°, and 25°CA BTDC) by changing the thickness of advance shim. All tests were conducted at four different loads (5, 10, 15, and 20 Nm) at constant engine speed of 2200 rpm. The experimental test results showed that BSFC, BSEC, combustion efficiency, and NO x and CO 2 emissions increased as BTE, rate of heat release, peak cylinder pressure, smoke number, and CO and UHC emissions decreased with an increasing amount of methanol in the fuel blend. In comparison to the values at the original injection timing (20°CA BTDC), the values at the retarded injection timing (15°CA BTDC) of peak cylinder pressure, rate of heat release, combustion efficiency, and NO x and CO 2 emissions decreased, while smoke number and UHC and CO emissions increased at all test conditions. On the other hand, The advanced injection timing (25°CA BTDC), smoke number, and UHC and CO emissions diminished and peak cylinder pressure, rate of heat release, combustion efficiency, and NO x and CO 2 emissions increased at all test conditions. In terms of BSFC, BSEC, and BTE, retarded and advanced injection timings gave negative results in all fuel blends compared to original injection timing.

Experimental and Kinetic Modeling Study of Methanol Ignition and Oxidation at High Pressure

“…At the outlet of the reactor, the pressure was reduced down to atmospheric pressure prior to analysis. A gas chromatograph, equipped with TCD and FID detectors, was used to measure CH 3 OH, C 2 H 5 OH, CH 4 , O 2 , CO, and CO 2 . The uncertainty of the measurements was estimated to be ±5%.…”

“…Its range of production sources and its chemical structure, with a high oxygen content and no C-C bonds, causes methanol to be one of the most important oxygenated additives. For these reasons, a number of studies have addressed the use of methanol-diesel blends in diesel engines [2][3][4][5]. Most of the authors conclude that the addition of methanol reduces the emissions of particulates and NO x , even though some reported results seem contradictory.…”

Autoignition of methanol: Experiments and computations

“…The utilization of a given fuel in an internal combustion engine is greatly influenced by its physical and chemical properties. The combustion of methanol in compression ignition engines in conjunction with diesel and diesel-like fuels has been extensively studied [4][5][6][7][8][9][10][11][12][13][14][15]. Similar combustion studies have also been conducted in spark ignition engines using gasoline and methanol fuels simultaneously [16][17][18][19][20].…”

Combustion Characteristics of an Indirect Injection (IDI) Diesel Engine Fueled with Ethanol/Diesel and Methanol/Diesel Blends at Different Injection Timings

“…The oxygenated alternative fuels such as methanol and ethanol have provided more oxygen during combustion. Therefore, the oxygenated alternative fuels and blends with gasoline and diesel fuel are more clean combustion processes than that of diesel and gasoline fuels [1][2][3][4][5][6][7]. The studies related to the alternative fuels should be enhanced for diesel engines especially for indirect injection (IDI) diesel engines.…”

“…Canakci et al [2] experimentally investigated the combustion and exhaust emissions of a single cylinder diesel engine at three (25, 20 or iginal injection timing and 15 o CA BTDC) different injection timings when methanol/diesel fuel blends were used from 0 to 15%, with an increment of 5%. The results indicated that the P max decreased and the ID increased with the increase of methanol mass fraction at all injection timings.…”