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Variable Valve Actuation system (VVA) is a technology developed for improving fuel economy, reducing emissions, and enhancing engine performance mainly by reducing pumping losses. Many automakers have used VVA in their engine projects with excellent results. Usually, VVA systems are built to control the valve events in four different ways: changing the amplitude of the valve lift, the valve opening angle, the valve closing angle or a combination of those modes. A special attention at the calibration activity is needed to reach the optimum performance of this system, beyond this, it was necessary to develop a different way to calibrate, much more focused on the development of the combustion and the gas exchange process requiring an intense use of a pressure indicating system. This work presents a comparison between different way of actuation in combustion analysis of a VVA system on a spark ignition engine.

In a torch ignition engine system the combustion starts in a prechamber, where the pressure increase pushes the combustion jet flames through calibrated nozzles to be precisely targeted into the main combustion chamber. The paper presents the layout of the prototype engine and the developed fuel injection system. It continues with a detailed description of the performance of the torch ignition engine running on a gasoline/ethanol blend for different mixture stratification levels as well as engine speeds and loads. Also detailed analyses of specific fuel consumption, thermal and combustion efficiency, specific emissions of CO2 and the main combustion parameters are carried out. A supplementary decrease in NOX emissions was obtained by use of Brazilian pure hydrated fuel. The paper concludes presenting the main results obtained in this work, which show significant increase of the torch ignition engine performance in comparison with the commercial baseline engine.

In a torch ignition engine system the combustion starts in a prechamber, where the pressure increase pushes the combustion jet flames through calibrated nozzles to be precisely targeted into the main combustion chamber. The paper presents the layout of the prototype engine and the developed fuel injection system. It continues with a detailed description of the performance of the torch ignition engine running on a gasoline/ethanol blend for different mixture stratification levels as well as engine speeds and loads. Also detailed analyses of specific fuel consumption, thermal and combustion efficiency, specific emissions of CO2 and the main combustion parameters are carried out. A supplementary decrease in NOX emissions was obtained by use of Brazilian pure hydrated fuel. The paper concludes presenting the main results obtained in this work, which show significant increase of the torch ignition engine performance in comparison with the commercial baseline engine.

In a torch ignition engine system the combustion starts in a prechamber, where the pressure increase pushes the combustion jet flames through calibrated nozzles to be precisely targeted into the main combustion chamber. The paper presents the layout of the prototype engine and the developed fuel injection system. It continues with a detailed description of the performance of the torch ignition engine running on a gasoline/ethanol blend for different mixture stratification levels as well as engine speeds and loads. Also detailed analyses of specific fuel consumption, thermal and combustion efficiency, specific emissions of CO2 and the main combustion parameters are carried out. A supplementary decrease in NOX emissions was obtained by use of Brazilian pure hydrated fuel. The paper concludes presenting the main results obtained in this work, which show significant increase of the torch ignition engine performance in comparison with the commercial baseline engine.