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The medium and heavy-duty powertrain industry trend is to reduce reliance on diesel fuel and is aligned with continued efforts of achieving ultra-low emissions and high brake efficiencies. Compression Ignition (CI) of late cycle Directly Injected (DI) Natural Gas (NG) shows the potential to match diesel performance in terms of brake efficiency and power density, with the benefit of utilizing a lower carbon content fuel. A primary challenge is to achieve stable ignition of directly injected NG over a wide engine speed and load range without the need for a separate ignition source. This project aims to demonstrate the CI of DI NG through experimental studies with a Single Cylinder Research Engine (SCRE), leading to the development of a mono-fueled NG engine with equivalent performance to that of current diesel technology, 25% lower CO2 emissions, and low engine out methane emissions.

Retaining the diesel combustion process but burning primarily natural gas offers diesel-like efficiencies from a natural-gas fuelled heavy-duty engine. This combustion event is limited by the injection pressure of the fuel, as this dictates the rate of mixing and hence of combustion. Typical late-cycle direct injection applications are limited to approximately 300 bar fuel pressure. The current work reports on tests for the first time at natural gas injection pressures up to 600 bar. The results show that significant efficiency and particulate matter reductions can be achieved at high loads, especially at higher speeds where the combustion is injection rate limited at conventional pressures. Increases in combustion noise and harshness are a drawback of higher pressures, but these can be mitigated by reducing the diameter of the nozzle gas holes to control the fuel injection rate.

In the past few decades, use of energy resources in industrial and transportation sector have reached to its peak resulting in depleting resources and environment squalor. Vegetable oils, which have properties comparable to diesel fuel, are considered promising alternative fuels for unmodified diesel engines. However, high viscosity of vegetable oils is a major challenge which could be reduced by blending with alcohols. The aim of the present study was to investigate the suitability of orange peel oil and n-butanol blends as an alternative fuel for CI engine. Various blends of butanol with orange peel oil were prepared on volumetric basis and named as B10OPO90 (10% n-butanol and 90% orange peel oil), B20OPO80 (20% n-butanol and 80% orange peel oil), B30OPO70 (30% n-butanol and 70% orange peel oil) and B40OPO60 (40% n-butanol and 60% orange peel oil). All blends were found homogenous and various physico-chemical properties were evaluated in accordance to relevant standards.

Diesel Engines are widely used in transportation, industrial and agriculture sectors worldwide due to their versatility and ruggedness. However, they also emit harmful emissions detrimental to human health and environment. Apart from environmental degradation, the perturbation in international crude oil prices is also mandating use of renewable fuels. In this context, vegetable oils such as Jatropha Curcas due to their carbon neutral nature and widespread availability, seems to present a promising alternative to the mineral diesel. Straight vegetable oils (SVO) are not recommended for direct diesel engine application due to their higher viscosity, poor volatility etc. and dilution of straight vegetable oil may effectively enable its direct application in unmodified diesel engines. In the present study, Jatropha oil was diluted with n-Butanol to improve the fuel properties of the blend.

The rising cost and exponential depletion of crude oil in international market has provided an opportunity for the researchers to evaluate the utilization and suitability of various renewable fuels. Amongst variety of alternative fuels, biofuels have the potential to mitigate the vulnerability and the adverse effects of use of fossil fuels. Vegetable/plant oil is better proposition as alternative fuel for diesel engine having much advantage over other alternative fuels. Orange oil from its peel has a huge potential and can be used as an alternate fuel at the most economical purchase rate. In the present investigation experiments were carried out to evaluate performance and emission characteristics of Orange peel oil methyl ester blends (OPOME) (10%, and 20% by volume) on unmodified diesel engine. The properties of these blends were found to be comparable to diesel and confirming to both the American and European standards.

Ever increasing consumption of petroleum derived fuels has been a matter of grave concern due to rapidly depleting global reserves and alarming levels of emissions leading to global warming and climate change. Exhaustive research has been carried out globally to evaluate the suitability of variety of renewable fuels for internal combustion engine applications. Amongst them, vegetable oil methyl esters or biodiesel seem to be a promising alternative for diesel in vital sectors such as transportation, industrial and rural agriculture. For quite some time, the focus for production of biodiesel has shifted towards non-edible oil feedstock from the edible ones, mostly due to food security issues. One such non-edible oil, locally known as Mahua in Indian subcontinent, is a very promising feed stock for biodiesel production. In the present investigation, 5%, 10%, 15% and 20% (v/v %) blends of mahua oil methyl ester (MOME) and diesel were prepared.

In this paper, benefits of high performance CFD computations for ground vehicle aerodynamics are discussed with the examples of Ahmed body and Formula SAE external aerodynamics. Both problems are highly compute intensive in terms of physics and their grid resolutions. Grid resolution is usually kept high to resolve flow separation, wake kind of complex physical phenomenon. For this, computations have been performed for more than 20 million cells grid. Firstly, Reynolds Averaged Navier-Stokes (RANS)-based turbulence study of Ahmed model is done for three slant angle variations, 25°, 30°, and 35°. Sensitivity of solver on solution is analyzed by a grid refinement study. The 2 million and 22 million cells mesh are used for the detailing of solution accuracies and solver speed up. Commercial solver, CFD++, and open source solver, OpenFOAM, are used for RANS computations. Their speed up test is done on supercomputer Eka.

Noise computations are carried out for sunroof opening in automotives at a resonating speed. First, the behavior of baseline opening shape is analyzed through frequency spectrum obtained from acoustic analysis. Then the opening shape is changed to reduce the sound pressure level of buffeting noise. The analysis with new shape is able to reduce the Noise dB levels up to 5dB. Commercial software, Fluent, is used to compute the turbulent flow field. Large-Eddy Simulation is used for better prediction of fluctuating components. Acoustic results obtained from Ffowcs-Williams and Hawkings equations are well compared with other's work.