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The effect of variation in injection pressure and Injection timing on the performance and exhaust emission characteristics of a direct injection, naturally aspirated Diesel engine operating on Diesel and Diesel-Biodiesel Blends were studied. A three-way factorial design consisting of four levels of injection pressure (150,210, 265,320 bar), four levels of injection timing (19° btdc, 21.5° btdc, 26° btdc, and 30.5° btdc) and five different fuel types (D100, B10, B20, B40, and B60) were employed in this test. The experimental analysis shows that when operating with Linseed Oil Methyl Ester-Diesel blends, we could increase the injection pressure by about 25% over the normal value of 20MPa. The engine performance and exhaust emission characteristics of the engine operating on the ester fuels at advanced injection timing were better than when operating at increased injection pressure.

Increasing the efficiency of engine auxiliary systems have become a challenge. Oil pump, identified for this study, is one such engine system which is used for lubrication of engine parts. To achieve higher efficiencies, there is a need for math-based analysis and design. This can be achieved by means of Computational Fluid Dynamics (CFD). The main aim of this paper is to simulate the flow through Gerotor Oil pump using Computational Fluid Dynamics. A 3D model of the entire flow domain is created and meshed in preprocessor GAMBIT. The mesh for various pressure outlet conditions is exported to FLUENT solver for analysis. The predicted results are validated with the experimental results. The comparison shows that the CFD predictions are in good agreement with experimental results. In particular, such a simulation offers a scope for visualizing the flow through the Gerotor oil pump.

A single cylinder, direct injection diesel engine was run on water diesel emulsion at a constant speed of 1500 rpm under variable load conditions. Water to diesel ratio of 0.4 on the mass basis was used. Tests indicated a considerable reduction in smoke and NO levels. This was accompanied by an increase in brake thermal efficiency at high outputs. HC & CO levels, ignition delay and rate of pressure rise went up. The heat release rate in the premixed burn period was higher. When the oxygen concentration in the intake air was enhanced in steps up to 25% along with the use of water diesel emulsion, the brake thermal efficiency was improved and there was a further reduction in the smoke level. HC and CO levels also dropped. NO emission went up due to increased temperature and oxygen availability. An oxygen concentration of 24% by volume was optimal as the NO levels were near about base diesel values.

This paper deals with the experimental investigation carried out to study the effect of expansion ratio (ER) on the brake thermal efficiency of a spark ignition ( S.I. ) engine. Intake valve closure timing (IVCT) and clearance volume have been suitably altered to achieve different ERs and compression ratios (CRs). For the modified engines the ratio of ER to CR ranges from 1:1 to 2.27:1, for CRs of 6,7, and 8:1. The results have been compared with the standard version of the engine with compression ratio of 7 and 8:1. Brake thermal efficiency improvement up to 35% has been achieved with a combination of variable IVCT (VIVCT) and variable CR (VCR) at part - load operation. Results show that in this system CR can be lowered without penalizing the thermal efficiency of the engine. Results indicate that the thermal efficiency of an Extended Expansion Engine with a CR of 6:1 and ER/CR equal to 1.5 is equal to the thermal efficiency of a standard engine with a CR of 8:1.

Three catalysts based on X-zeolite have been developed by exchanging its Na+ ion with Copper, Nickel and Vanadium metal ions and tested in a stationary SI engine exhaust to observe their potentialities for NOx and CO controlling. The catalyst Cu-X, in comparison to Ni-X and V-X, exhibits much better NOx and CO reduction performance at any temperature. Maximum NOx conversion efficiencies achieved with Cu-X, Ni-X and V-X are 62.2%, 59.7% and 56.1% respectively. Unlike noble metals, the doped X-zeolite catalysts, studied here, maintain their peak NOx reduction performance through a wider range of A/F ratio. Back pressure developed across the catalyst bed is found to be well within the acceptable limits.

In this work methanol was port injected while diesel was injected using a common rail system in a single cylinder non-road CI engine. Experiments were conducted with single (SPI) and double (DPI - pilot and main) injection of the directly injected diesel at 75% load and at a constant speed of 1500 rpm. The effects of methanol to diesel energy share (MDES) and injection scheduling on combustion stability, efficiency and emissions were evaluated. Initially, in the SPI mode, the methanol to diesel Energy Share (MDES) was varied, while the injection timing of diesel was always fixed for best brake thermal efficiency (BTE). Increase in the MDES resulted in a reduction in NOx and smoke emissions because of the high latent heat of vaporization of methanol and the oxygen available. Enhanced premixed combustion led to a raise in brake thermal efficiency (BTE). Coefficient of variation of IMEP, peak pressure and BTE were deteriorated which limited the usable MDES to 43%.

Gasoline Direct Injection (GDI) engine is known for its higher power and higher thermal efficiency. Researchers are steadily determining and resolving the problems of fuel injection in a GDI engine. In order to meet the stringent emission norms such as PM and NOx emitted by a GDI engine, it is necessary to investigate the microscopic spray characteristics and fuel-air mixing process. This paper aims to share the fundamental knowledge of the interacting mixture preparation mechanisms at the wide range of fuel injection pressures. The investigations were carried out at five different fuel injection pressures viz: 40, 80, 120, 160, 200 bar, for 24 mg fuel per injection. A high speed CCD camera was used to determine the macroscopic spray characteristics of the GDI injector. It was found that spray penetration length increased with increasing fuel injection pressure. Phase Doppler Interferometry (PDI) was used to determine the droplet size and droplet velocity for different test fuels.

Nowadays, the automotive engines are downsizing, thus offering limited space for engine intake air filter media. This results in higher aerosol velocity through the filter media. At a higher velocity, the aerosol particles reenter into the fluid stream and thereafter penetrate through the filter media. This causes significant reduction in filtration efficiency. Here, an attempt is made to understand the particle penetration behavior of automotive engine intake air filter media. To establish the flow field, numerical simulations are carried out on a panel type pleated air filter with pleat height 26 mm, pleat pitch 4.5 mm and pleat angle 2.50 degree. A series of tests are conducted using ISO 12103 A2 fine dust on a flat cellulosic paper filter media at a range of velocities derived numerically. The methodology followed for modeling the fibrous media using finite volume commercial CFD code for analyzing the flow field is presented.

Gasoline direct injection (GDI) technology is already in use in four wheeler applications owing to the additional benefits in terms of better combustion and fuel economy. The air-assisted in-cylinder injection is the emerging technology for gasoline engines which works with low pressure injection systems unlike gasoline direct injection (GDI) system. GDI systems use high pressure fuel injection, which provides better combustion and reduced fuel consumption. It envisages small droplet size and low penetration rate which will reduce wall wetting and hydrocarbon emissions. This study is concerned with a CFD analysis of an air-assisted injection system to evaluate mixture spray characteristics. For the analysis, the air injector fitted onto a constant volume chamber (CVC) maintained at uniform pressure is considered. The analysis is carried out for various CVC pressures, mixture injection durations and fuel quantities so as to understand the effect on mixture spray characteristics.

The study of aerodynamic forces in hypersonic environments is important to ensure the safety and proper functioning of aerospace vehicles. These forces vary with the angle of attack (AOA) and there exists an optimum angle of attack where the ratio of the lift to drag force is maximum. In this paper, computational analysis has been performed on a blunt cone model to study the aerodynamic characteristics when hypersonic flow is allowed to pass through the model. The flow has a Mach number of 8.44 and the angle of attack is varied from 0º to 20º. The commercial CFD solver ANSYS FLUENT is used for the computational analysis and the mesh is generated using the ICEM CFD module of ANSYS. Air is selected as the working fluid. The simulation is carried out for a time duration of 1.2 ms where it reaches a steady state and the lift and drag forces and coefficients are estimated. The pressure, temperature, and velocity contours at different angles of attack are also observed.