06-01-2015, 12:28 AM
I want information about the vehicles which are using vva mechanism and about bench market and about project and how we approch to enchance engine Performance and Emission Requirement
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variable valve actuating mechanism to enchance engine performance and emission ppt t
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I want information about the vehicles which are using vva mechanism and about bench market and about project and how we approch to enchance engine Performance and Emission Requirement
12-04-2017, 01:02 PM
The vast majority of car and truck engines operate either with the SI engine or the CI engine. The valves of these engines have a mechanically driven valve movement fixed with respect to the position of the crankshaft for all operating conditions. These valve movements, such as (valve lift profile, valve event and opening duration), are determined during the design stage of the motor by fixing the cam profile and its position. Valve times were designed, in general, for average performance and had no method of varying timing or elevation. This procedure provided adequate operation at medium speeds and loads, but was not optimized for high or low speeds and at idle. In the modern world, one of the biggest concerns is the increasingly exhausting oil supply. The automotive industry especially impacted, in 2011, the world consumed 85 million barrels of oil a day. Oil remains an important source of energy, as well as in the future. Despite the fact that the world consumption of fossil fuels continues to grow to 118 million barrels per day by 2030. In addition, the released emission of the internal combustion engines that contaminate the environment. Global demand for cars is on the rise - a forecast predicts that the number of vehicles worldwide will increase five-fold by 2050 to 2.9 billion. Control of greenhouse gas emissions has begun to add to the numerous constraints that vehicle manufacturers meet. Reducing engine fuel consumption becomes a primary requirement for manufacturers and designers, as well as complying with current and future emissions laws naturally.
The effects of variable valve timing and elevation are studied to improve the thermal efficiency of a diesel engine, keeping emission levels low. Under high load conditions, the anticipated closing of one of the intake valves or the early opening of the intake valve improves the vortex intensity without higher pump losses and the delayed closing of the intake valve reduces the Effective compression ratio, and advanced fuel injection timing. Accordingly, a low NOx formation and an improved thermal performance can be achieved simultaneously. Under low load conditions, injected fuel is dispersed in the cylinder by air turbulence due to the small amount of fuel, and the increased effective compression ratio achieved by the early closing of the intake valve is effective to reduce emissions Of hydrocarbons. It is confirmed that the variable valve timing and synchronization system introduced in this research can flexibly change the engine parameters governing the combustion of the engine under various engine operating conditions. As a result, a 40 percent reduction in engine NOxemissions and a 4 percent improvement in fuel consumption in the new European Driving Cycle (NEDC) is achieved. In addition, the low-end torque could be increased by 40 percent by using the exhaust pressure pulse by adjusting the exhaust valve opening time and the overlap of the intake and exhaust valve opening around the Top dead center in the intake stroke. To improve these benefits, a new piston chamber with deep valve bags is developed and its effect investigated.
The effects of variable valve timing and elevation are studied to improve the thermal efficiency of a diesel engine, keeping emission levels low. Under high load conditions, the anticipated closing of one of the intake valves or the early opening of the intake valve improves the vortex intensity without higher pump losses and the delayed closing of the intake valve reduces the Effective compression ratio, and advanced fuel injection timing. Accordingly, a low NOx formation and an improved thermal performance can be achieved simultaneously. Under low load conditions, injected fuel is dispersed in the cylinder by air turbulence due to the small amount of fuel, and the increased effective compression ratio achieved by the early closing of the intake valve is effective to reduce emissions Of hydrocarbons. It is confirmed that the variable valve timing and synchronization system introduced in this research can flexibly change the engine parameters governing the combustion of the engine under various engine operating conditions. As a result, a 40 percent reduction in engine NOxemissions and a 4 percent improvement in fuel consumption in the new European Driving Cycle (NEDC) is achieved. In addition, the low-end torque could be increased by 40 percent by using the exhaust pressure pulse by adjusting the exhaust valve opening time and the overlap of the intake and exhaust valve opening around the Top dead center in the intake stroke. To improve these benefits, a new piston chamber with deep valve bags is developed and its effect investigated.
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