Effects of Water Ratio in Hydrous Ethanol on the Combustion and Emissions of a Hydrous Ethanol/Gasoline Combined Injection Engine under Different Excess Air Ratios

Abstract

Ethanol is usually combined with gasoline to manufacture ethanol−gasoline with excellent combustion characteristics. However, extracting water from hydrous ethanol to manufacture anhydrous ethanol consumed much energy, which increases the production cost of ethanol− gasoline. Many researchers have studied the combustion and emissions of hydrous ethanol−gasoline to explore the application of hydrous ethanol− gasoline as the fuel for spark-ignition engines. Most previous studies changed the hydrous ethanol ratio with fixed purity in hydrous ethanol− gasoline to study the effects of hydrous ethanol. Different from previous studies, this paper studied the effects of water ratio (Wr) in hydrous ethanol on the combustion and emissions of a hydrous ethanol/gasoline combined injection engine under different excess air ratio (λ) values. The ratios of ethanol and gasoline keep constant, while the purity of hydrous ethanol changes during the research. The experiment adopted the combined injection mode with hydrous ethanol direct injection plus gasoline port injection; the direct injection ratio was 20%. The experiment set three λ (0.9, 1, and 1.2) and five Wrs (0, 5, 10, 15, and 20%). The test engine's speed was 1500 rpm, and the intake manifold absolute pressure was 48 kPa. Results showed that water inhibited combustion, prolonged CA 0-10 and CA 10-90, reduced P max and T max , and delayed AP max ; larger λ made the deterioration on combustion more obvious, and the smaller λ had a larger tolerance to water. Water could increase torque and improve emissions, but different parameters corresponded to different optimal Wrs. For torque, the optimal Wr was 5%. For HC emissions, the optimal Wr was 0%; for CO emissions, the optimal value was 5%; and for NO x emissions, the best value was 20%. The best Wr was 10% for particle number (PN) emissions. Under the optimal Wr condition, when λ values were 0.9, 1, and 1.2, compared with pure gasoline, the torque increased by 7.

Influence of fuel mixture and catalyst on the ethanol burner flue gas composition

“…Co-combustion of methanol with ethanol also caused lower values than in the case of ethanol combustion (50/50 -decrease by 16%; 70/30 -decrease by 15%; 50/50 -decrease by 7%). Comparable results were obtained during the ethanol/water mixtures combustion described in studies of Breaux [14], Sileghem et al [29] and Li et al [32]. Catalyst usage did not affect the values of emitted NO x .…”

Effect of Exhaust Gas Recirculation and Spark Timing on Combustion and Emission Performance of an Oxygen-Enriched Gasoline Engine

“…2,3 In many studies on engine clean combustion technology, renewable oxyfuels, such as methanol, ethanol, and butanol, were the most prominent. 4,5 Their oxygen atoms contained in the molecular structure can help to increase the chain-reacting rate and improve the microscopic combustion state of the mixture. Compared with traditional alkane fuels, oxyfuels have cleaner combustion products.…”

“…In many studies on engine clean combustion technology, renewable oxyfuels, such as methanol, ethanol, and butanol, were the most prominent. , Their oxygen atoms contained in the molecular structure can help to increase the chain-reacting rate and improve the microscopic combustion state of the mixture. Compared with traditional alkane fuels, oxyfuels have cleaner combustion products. , Among the common oxyfuels, ethanol is the most widely used commercial fuel because of its lower toxicity, lower production cost, better evaporation characteristics, and superior combustion characteristic. , However, the large heat of vaporization and low vapor pressure endow the engine with poor cold start capability in cold weather . The dependence on crops makes them unable to be fully promoted in some food-stressed countries and regions .…”

“… 2 , 6 Among the common oxyfuels, ethanol is the most widely used commercial fuel because of its lower toxicity, lower production cost, better evaporation characteristics, and superior combustion characteristic. 5 , 7 However, the large heat of vaporization and low vapor pressure endow the engine with poor cold start capability in cold weather. 8 The dependence on crops makes them unable to be fully promoted in some food-stressed countries and regions.…”

Experimental and Numerical Study on the Effect of NO2 on n-Butanol/Biodiesel Dual-Fuel Combustion in a Compression Ignition Engine

“…The use of biomass oxygenated fuels in engines can alleviate their reliance on petroleum resources while also lowering soot emissions. The most widely investigated biomass fuels included alcohols (methanol, 22 ethanol, 23 and n -butanol 24 ), furans (2,5-dimethylfuran 25 and 2-methyl furan 26 ), and biodiesel. 27 Compared to methanol and ethanol, n -butanol has a greater energy density and hydrophobicity.…”