Effects of Methanol Substitution on Performance and Emission in a LPG-Fueled SI Engine
01 Nov 2019-pp 193-205
TL;DR: In this article, the effects of methanol substitution were investigated in reduction of NOx emissions at 100% throttle condition by injecting 10, 20 and 30% of methenol on energy basis into the intake port of engine.
Abstract: The current rate of depletion of fossil fuels has created an imbalance in the energy exchange. Stricter emission standards are enforced in order to control the environmental pollution and global warming. Both these factors have led to a shift from usage of conventional fossil fuels to other alternative resources. LPG serves as a viable alternative option owing to its suitability to fuel SI engines and its obtainability from large scale shale gas reserves. Being a gas at atmospheric condition, it offers proper homogenization and is best suited for lean-burn conditions. Adding methanol in small amount to LPG lowers the combustion temperature due to the latent heat of vaporization and improves lean operation due to oxygen content contributing in reduction of NOx. This work is focused on NOx reduction as it is hazardous and main constituent in the formation of PM, smog and acid rains. An experimental study is conducted in a single cylinder diesel engine modified to operate as SI engine at an optimized compression ratio of 10.5:1 and 1500 rpm fueled by LPG. The effects of methanol substitution were investigated in reduction of NOx emissions at 100% throttle condition by injecting 10, 20 and 30% of methanol on energy basis into the intake port of engine. The results have been analyzed with Brake Effective Mean Pressure (BMEP) as it serves as an important yardstick to compare different criteria. The experiments were performed at BMEPs of 4, 4.5,5 and 5.5 bar. There is a significant improvement in brake thermal efficiency along with decrease in the NOx emission as the percentage of methanol in the fuel goes higher. The decrease in NOx is significant ranging from 83% at 4 bar BMEP to 12% at 5.5 bar. The lean operation was also improved on addition of methanol.
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TL;DR: In this article , the performance of an EPI + CDI engine at different compressed nature gas direct injection ratio (CDIr) and DIT was studied at the speed of 1500rmp, and the results showed that, with the increase of CDIr or the delay of direct injection timing (DIT), torque, Pmax and NOx first increases and then decreases; CA 10−90, CoVIMEP, CO and particle number (PN) first decreases and then increases; HC keeps decreasing.
5 citations
TL;DR: In this paper , the authors studied the performance of an ethanol spark ignition (SI) engine under lean-burn conditions with dual-injection with ethanol port injection and compressed natural gas (CNG) direct injection.
Abstract: Conventional ethanol spark ignition (SI) engines have poor fuel atomization and mixture formation. The objective of this paper is to improve the combustion and emission performance of ethanol SI engines under lean-burn conditions through the dual-injection mode with ethanol port injection and compressed natural gas (CNG) direct injection (CDI+EPI). This paper studies the engine performance at 1500 rpm under five CNG direct injection ratios (CDIr) and five excess air ratios (λ). The results show that as the CDIr increases under lean-burn conditions, the following occurs: the minimum advance for best torque (MBT), the coefficient of variation (CoVIMEP), and CO and HC emissions decrease; the crankshaft rotation or time with cumulative heat release rate ranging from 10% to 90% (CA 10–90) and NOx emissions first decrease and then increase; and torque, peak in-cylinder pressure (Pmax), and the λ limit first increase and then decrease. The larger the CDIr is, the less influence λ has on the MBT. When CDIr = 15%, the CoVIMEP can be effectively reduced, the engine can still work stably in all lean-burn conditions, and the λ limit will reach the maximum value of 1.73, 19.31% higher than that of the original engine (CDIr = 0). When λ = 1.1, CO emissions decrease the most and HC emissions decrease the least. At this time, CO and HC emissions decrease by 1.56 vol % and 30 ppm, respectively, on average for every 0.1 decrease in λ. For CA 10–90, torque, and Pmax, λ = 1.1, 15% CDI, and 85% EPI is the optimal combination under lean-burn conditions. When CDIr ≥ 15%, NOx emissions are at an ideal level. Under lean-burn conditions, direct-injection CNG can form a good stratified natural gas/ethanol mixture in the cylinder, effectively improving the engine’s power and stability and reducing emissions. The λ = 1.1, 15% CDI, 85% EPI combination provides a cutting-edge and outstanding solution for a natural gas/ethanol combined injection SI engine.
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7,426 citations
TL;DR: In this paper, the performance and pollutant emission of a commercial SI engine using ethanol-gasoline blended fuels with various blended rates (0, 5, 10, 20, 30%).
614 citations
Book•
23 Aug 2013
TL;DR: A spark-ignition four-stroke gasoline engine, of the commonly mass-produced type having a plurality of cylinders provided each with two poppet valves mounted in a cylinder-head of the engine and constituting respectively an inlet valve, for passing a fuel-air mixture to the cylinder, and an exhaust valve for passing exhaust gases to an exhaust manifold of an engine, is given exhaust valves which are at least 7% greater in area than the inlet valves.
Abstract: A spark-ignition four-stroke gasoline engine, of the commonly mass-produced type having a plurality of cylinders provided each with two poppet valves mounted in a cylinder-head of the engine and constituting respectively an inlet valve, for passing a fuel-air mixture to the cylinder, and an exhaust valve for passing exhaust gases to an exhaust manifold of the engine, is given exhaust valves which are at least 7% greater in area than the inlet valves.
388 citations
TL;DR: In this article, a 3-cylinder port fuel injection engine was adopted to study engine power, torque, fuel economy, emissions including regulated and non-regulated pollutants and cold start performance with the fuel of low fraction methanol in gasoline.
263 citations
Book•
01 Jan 1995
TL;DR: In this article, basic principles of air-standard cycles and their analysis fuel-air cycles and actual cycles were reviewed. And the analysis of actual and air-air cycle parameters and characteristics of two-stroke engines were presented.
Abstract: Review of basic principles air-standard cycles and their analysis fuel-air cycles and their analysis actual cycles and their analysis fuels carburetion injection ignition combustion and combustion chambers engine friction and lubrication heat rejection and cooling measurements and testing performance parameters and characteristics two-stroke engines.
227 citations