Search

This study presents the parametric investigation of syngas fuelled homogeneous charge compression ignition (HCCI) engine. The chemical kinetic simulation of the syngas HCCI engine is performed using the stochastic reactor model (SRM). This study first compares and evaluates the performance of different reaction mechanisms for the HCCI engine. The experimental combustion pressure data is compared with numerically investigated combustion pressure to validate the reaction mechanisms. Results indicate that a numerically simulated combustion pressure using a detailed reaction mechanism consisting of 173 reactions and 32 species (CRECK-2014) is well-matched with the profile of experimental combustion pressure. The validated reaction mechanism is further used to investigate the HCCI engine at different engine speeds for various equivalence ratio (ϕ) , syngas composition (hydrogen addition (H 2 :CO)) and inlet valve closing temperature (T i v c). The sensitivity analysis is performed to find the prominent reactions in the oxidation reaction mechanism. Based on the combustion characteristics, syngas HCCI maps are developed. The effect of engine operating conditions on combustion and emission characteristics is also investigated. Furthermore, the result of engine operating parameters on converting fuel energy into physical exergy, chemical exergy, work exergy, and heat loss exergy is also briefly discussed. • Parametric investigation of syngas fuelled HCCI engine conducted. • CRECK-2014 reaction mechanism consisting of 173-reactions and 32-species is used. • Syngas HCCI operating maps for optimal performance are developed. • Crank angle-based exergy analysis for syngas HCCI engine is performed. • X w o r k increases with an increase in the ϕ for constant engine speed, T i v c , and H 2 : C O. [ABSTRACT FROM AUTHOR]

In present study, the effect of fuel premixing ratio, direct fuel injection timings and engine compression ratio on the soot particle emissions in nano-size range from a non-road compression ignition engine is investigated. Experiments are conducted on modified dual fuel single cylinder engine at 1500 rpm. To run the engine in dual fuel mode, port fuel injection (PFI) system is installed by modifying intake manifold of the engine and developing a PFI controller. Experiments are conducted for various fuel premixing ratio of gasoline/methanol-diesel at different engine load, diesel fuel injection timing and compression ratios. Differential mobility spectrometer based particle sizer is used for investigation of the soot particle number-size distribution, surface area-size distribution, particle mass-size distribution and total particle number concentration from the engine exhaust at various test conditions. Results revealed that total particle number concentration is higher at full engine load and increases with fuel premixing ratio (especially in case of methanol-diesel dual fuel operation). Additionally, the peak particle number and mass concentration reduces with an increase in compression ratio of the engine. [ABSTRACT FROM AUTHOR]

Analysis of measured in-cylinder pressure data provides various parameters that characterize engine combustion process. Advanced engine control technologies use cylinder pressure based combustion parameters for closed loop control. Four step signal processing (i) absolute pressure correction, (ii) crank angle position referencing, (iii) cycle averaging and (iv) filtering is typically applied to get sufficiently accurate cylinder pressure data for an engine cycle. This paper focuses on cycle averaging and filtering of in-cylinder pressure signal from a conventional compression ignition (CI) engine. Experiments are conducted at different engine load and compression ratios at 1500 rpm. The in-cylinder pressure trace of 2500 consecutive engine cycles is recorded and analyzed. Effect of in-cylinder pressure signal noise and cyclic variation on combustion analysis is investigated. A method based on standard deviation of pressure and pressure rise rate is used to find sufficient minimum number of engine cycles to be recorded for averaging to get reasonably accurate pressure data independent of cyclic variability. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nanoparticle and carbonyl emission from methanol-diesel dual fuel was investigated. • Health risk assessment for nanoparticle and carbonyl emissions was conducted. • Methanol-diesel engines carbonyl emission has a higher cancer risk potential. • Diesel engine nanoparticles showed higher lung load and longer retention period. • At high loads, Methanol in diesel engines can reduce health risks significantly. Engine-emitted nanoparticles pose a threat to respiratory health, prompting the exploration of solutions like low carbon alternative fuels (methanol) and reactivity-controlled compression ignition (RCCI) engines. However, employing methanol in RCCI engines releases carcinogenic carbonyl compounds. The present study aims to experimentally investigate nanoparticle and carbonyl emissions from conventional diesel (CDC), gasoline-diesel RCCI (GD-RCCI) and methanol-diesel RCCI (MD-RCCI) engines. This study focuses on predicting lung loading caused by emitted nanoparticles and the potential cancer risk associated with carbonyl compounds. The investigation explores the impact of engine load (lower and medium) and fuel premixing ratio (r p) on particle and carbonyl emissions in RCCI engines. Findings reveal that MD-RCCI reduces total particle number (TPN) emissions by 60% compared to CDC. Results indicate that the concentration of nucleation mode particles (NMPs) decreases as engine load increases, while accumulation mode particles (AMPs) increase for both CDC and MD-RCCI combustion modes. With an increase in r p , the NMPs in the MD-RCCI and GD-RCCI engines are increased. Furthermore, the emission of HCHO and CH 3 CHO decreases with an increase in engine load. As the r p increases, HCHO and CH 3 CHO increase significantly. The forecast for lung loading reveals that nanoparticles emitted by CDC show a 30 % higher lung load compared to MD-RCCI. Additionally, as engine load increases, lung loading due to particles increases in CDC and decreases in MD-RCCI. In all test conditions, RCCI combustion demonstrates lower lung retention compared to CDC engine. The lung loading of particles of MD-RCCI decreases significantly with an increase in premixing ratio for a constant load as compared to GD-RCCI. The MD-RCCI engine shows higher cancer risk potential as compared to CDC and GD-RCCI engines. Operating the MD-RCCI engine at medium loads is advantageous for environmental and human health considerations. [ABSTRACT FROM AUTHOR]

Highlights: [•] Fuel injection pressure & timings affect engine performance, emissions and combustion. [•] Rapid combustion, higher cylinder pressure & ROHR at advanced injection timings. [•] Superior performance at lower FIP giving lower BSFC & emissions, & higher BTE. [•] Emission characteristics improve with advanced fuel injection timings. [•] Particulate number concentration in a CI engine increases with increasing engine load. [Copyright &y& Elsevier]