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Carbon Capture and Storage (CCS) techniques in combination with oxy-fuel combustion have been applied as an effective way to achieve nitrogen-free combustion and zero-carbon emissions. The present study has been carried out computationally in the framework of a European project (RIVER) (funded by Interreg North-West Europe) to explore the effect of intake charge temperature on oxy-fuel combustion in an HSDI diesel engine under HCCI combustion mode. Experimental data obtained from a Ford Puma common-rail diesel engine for a conventional part-load condition at 1500 rev/min and 6.8 bar IMEP have been used to validate the CFD model. To simulate the combustion process of HCCI, a reduced chemical n-heptane-n-butanol-PAH model has been adopted. The model has 349 elementary reactions and 76 species. The simulation has been carried out at five different intake charge temperatures (140°C, 160°C, 180°C, 200°C, and 220°C) and five different intake oxygen percentages (15%, 17%, 19%, and 21% v/v).

As the impacts of global warming have become increasingly severe, Oxy-Fuel Combustion (OFC) has been widely considered as a promising solution to reduce Carbon Dioxide (CO2) for achieving net-zero emissions. In this study, a one-dimensional simulation was carried out to study the implementation of OFC technology on a practical turbocharged 4-cylinder Gasoline Direct Injection (GDI) engine with economical oxygen-fuel ratios and commercial gasoline. When the engine is converted from Conventional Air-fuel Combustion (CAC) mode to OFC mode, and the throttle opening, oxygen mass fraction, stoichiometric air-fuel ratio (lambda = 1) are kept constant, it was demonstrated that compared to CAC mode, θF gets a remarkable extension whereas θC is hardly affected. θF and θC are very sensitive to the ignition timing, and Brake Specific Fuel Consumption (BSFC) would benefit significantly from applying Maximum Brake Torque (MBT) ignition timing.

Oxyfuel combustion and nitrogen-free combustion coupled with Carbon Capture and Storage (CCS) techniques have been recently proposed as an efficient method to achieve carbon free emissions and to improve the combustion efficiency in diesel engines. In this study, a 3-D computational fluid dynamics model has been used to evaluate the influence of oxyfuel-HCCI combustion on engine operating conditions and combustion characteristics in a HSDI diesel engine. Investigations have conducted using four different diluent strategies based on the volume fraction of pure oxygen and a diluent gas (carbon dioxide). The first series of investigations has performed at a constant fuel injection rating at which 4.4 mg of fuel has injected per cycle. In the second part of analysis, the engine speed was maintained at 1500 rev/min while the engine loads were varied by changing the fuel injection rates in the range of 2.8 to 5.2 mg/cycle.

Wall temperature in GDI engine is influenced by both water jacket and gas heat source. In turn, wall temperature affects evaporation and mixing characteristics of impingement spray as well as combustion process and emissions. Therefore, in order to accurately simulate combustion process, accurate wall temperature is essential, which can be obtained by conjugate heat transfer (CHT) and piston heat transfer (PHT) models based on mapping combustion results. This CHT model considers temporal interaction between solid parts and cooling water. This paper presents an integrated methodology to reliably predict in-cylinder combustion process and temperature field of a 2.0L GDI engine which includes engine head/block/gasket and water jacket components. A two-way coupling numerical procedure on the basis of this integrated methodology is as follows.

This research presents an experimental study of the laminar burning combustion and emission characteristics of premixed methane -dissociated methanol-air mixtures in a constant volume combustion chamber. All experiments were conducted at 3 bar initial pressure and 373K initial temperature. The dissociated methanol fractions were from 20% to 80% with 20% intervals, and the equivalence ratio varied from 0.6 to 1.8 with 0.2 intervals. The images of flame propagation were visualized by using a schlieren system. The combustion pressure data were measured and exhaust emissions were sampled with a portable exhaust gas analyzer. The results show that the unstretched laminar burning velocities increased significantly with dissociated methanol enrichment. The Markstein length decreased with increasing dissociated methanol fraction and decreasing equivalence ratio.

In the present study, we developed a reduced TRF-PAH chemical reaction mechanism consisted of iso-octane, n-heptane and toluene as gasoline surrogate fuels for GDI (gasoline direct injection) spark ignition engine combustion simulation. The reduced mechanism consists of 85 species and 232 reactions including 17 species and 40 reactions related to the PAHs (polycyclic aromatic hydrocarbons) formation. The present mechanism was validated for extensive validations with experimental ignition delay times in shock tubes and laminar flame speeds in flat flame adiabatic burner for gasoline/air and TRF/air mixtures under various pressures, temperatures and equivalence ratios related to engine conditions. Good agreement was achieved for most of the measurement. Mole fraction profiles of PAHs for n-heptane flame were also simulated and the experimental trends were reproduced well. The vapor-phase and particulate-bound PAHs existed in GDI engine exhaust were sampled and analyzed by GC-MS.

The aim of this research is to experimentally investigate the effects of combustion parameters [ignition timings, injection timings, excess air ratio (λ)] and lubricating oil on particulate matter (PM) emissions from a 2.0 L turbo-charged gasoline direct injection (T-GDI) engine fueled with gasoline (octane number = 97), methanol/gasoline blends and pure methanol. The results of this paper show that the PM number concentration mostly presents a typical bimodal distribution in figures. The particle number concentration mainly concentrates in the nucleation mode. With the increase of methanol volume fraction in the blended fuel, the PM emissions decrease significantly. Furthermore, there are few particles when the engine fueled with pure methanol. As advancing ignition timing, the total PM number rises by over about 200%. Under the pre-ignition condition, the higher in-cylinder temperature may also accelerate the formation of the nucleation mode particles.