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In the 21st Century, a majority of both engine and vehicle development is concerned with environmental laws pointed primarily towards the limitation and control of engine emissions. Increasingly stringent emissions and fuel economy standards have long remained a source of challenges for research in automobile engine technology development towards the more thermally efficient and less polluting engine. The Exhaust Gas Recirculation (EGR), Variable Compression Ratio (VCR) and Variable Valve Actuation (VVA) are the known ways for improvement of fuel economy, emission and performance. There is a high potential in reducing the exhaust emissions, especially NOx emissions by EGR, a principle technique used to control the SI engine NOx emission. A fraction of the exhaust gases is being re-circulated through a control valve from the exhaust to the engine intake system. The re-circulated exhaust gas usually mixes with the fresh fuel-air mixture just below the throttle valve, mainly as a result of reduction in the maximum combustion temperature. The level of NOx production is very sensitive to this temperature (this, incidentally, has discouraged the development of the so-called adiabatic engine in which fuel economy is improved by reducing in-cylinder heat losses). The higher compression ratio leads to the higher SI engine efficiency. The fuel economy and efficiency of SI engines has been improved by the VCR technique. In order to vary the compression ratio, some methods of varying the geometric compression ratio through changing the clearance volume is required. Modification of the compression ratio is being done by moving the cylinder head, variation of combustion chamber volume using a secondary piston or valve, variation of piston deck height, modification of connecting rod geometry, moving the crankpin within the crankshaft, and moving the crankshaft axis. Varying the engine valve-open duration, lift and phasing are known ways to improve engine performance, increase fuel
Your Price $195.00
List Price $195.00