Abstract:One of the important design parameters for internal combustion engines is the geometric compression ratio. It is defined by the ratio of the maximum volume of the combustion chamber at the bottom dead centre (BDC) piston position and a minimum volume of the combustion chamber at the top dead centre (TDC) piston position. Conventional engines have this parameter set unchangeable, what is not the solution ensuring optimal benefits coming from the heat release in the combustion process, especially under altering conditions of load and speed in which they perform powering the road vehicles. It is reflected mainly in exhaust emission problem. Despite a considerable progress, further improving the ecological and energetic performances of the piston engines faces severe system limits, elimination of which requires major changes in engine design, including conversion the fixed compression ratio into the flexible one. For such innovative engine designs with so-called variable compression ratio VCR feature the geometric compression ratio parameter is as the one of the operation regulators. Keywords:Variable Compression Ratio, Variable-Length Connecting rod, Variation of Combustion Chamber Volume, Connecting Rod Linkages, Variation of Piston Deck Height, Moving Crankshaft Axis I. INTRODUCTIONOne key features affecting thermal efficiency is the compression ratio, which is always a compromise in fixed compression ratio spark ignition (SI) engines. If the compression ratio is higher than the designed limit, the fuel will pre-ignite causing knocking, which could damage the engine. Generally, the operating conditions of SI engines vary widely, such as stop and go city traffic, highway motoring at constant speed, or high-speed freeway driving. Unfortunately, most of the time SI engines in city driving conditions operate at relatively low power levels under slow accelerations, low speeds, or light loads, which lead to low thermal efficiency and hence higher fuel consumption [1]. As the engine load decreases, the temperature in the end gas drops, so that high compression ratio could be employed without the risk of knocking in naturally aspirated or boosted engines. Raising the compression ratio from 8 to 14 produces an efficiency gain from 50 to 65 per cent (a 15 per cent gain), whereas going from 16 to 20 produces a gain from 67 to 70 per cent (a 3 per cent gain). The effects of compression ratio with respect to thermal efficiency. Designing high performance vehicles that are fuel efficient and clean is difficult since we also want them to remain inexpensive. It is therefore necessary to find simple, low cost and effective solutions and that is the whole strategy of the Variable Compression Ratio (VCR) engine producers. Far from being a revolution, VCR engines are a major evolution of conventional engines. The concept of variable compression ratio (VCR) promises improved engine performance, efficiency and reduced emissions. The higher cylinder pressures and temperatures during the early part of combustion and small resid...

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In a world where environment protection and energy conservation are growing concerns, the development of electric and hybrid vehicles (EV/HEV) has taken on an accelerated pace. The dream of having commercially viable electric/hybrid vehicles is becoming a reality. EVs and HEVs are gradually available in the market. This study reviews the present status of electric and hybrid vehicles worldwide, with emphasis on the engineering and technologies. The paper also includes a view on the latest development on batteries with high charge storage & vehicle chassis, suspension, body with embedded battery.