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In Brazil, in the last few years, there has been a tendency to the use of alternative fuels. One of them is Compressed Natural Gas (CNG) and it is used due to its low cost, low fuel consumption and available technology. An originally gasoline or alcohol fuel engine can be also fuelled by CNG with some modifications, turning it into a multi-fuel engine. Commonly, however, the original compression ratio is unchanged, not allowing to explore CNG higher resistance to knock. This work aims at obtaining and analyzing the 1.3-L 8v FIRE FLEX engine performance curves for different compression ratios. A 5th generation BRC CNG multi-point fuel injection system is used for 11:1, 12,5:1 and 15:1 compression ratios and a development engine control unit and its calibration software were used to perform the system electronic management.

In this work an analysis of the performance of a multi-fuel engine fuelled allowing for the concentration of alcohol in gasoline and the use of CNG. The engine used was a four cylinder, 1.242-L, multi-fuel engine in full load, respecting the air/fuel rate established by the manufactures in the engine original calibration. A CNG BRC 5th generation multi-point fuel injection system was installed in order to run with CNG. The calibration and adjustments were made using a development engine control unit for the different fuels. This work presents a comparison among the performance curves aiming to obtain the best relation among torque, power and specific fuel consumption for the various proposed configurations.

Trends of the automotive market require the application of new engine technologies, which allows for the use of different types of fuel. Currently available multi-fuel engines operate with constant compression ratio irrespective to the fuel being used, however for best performance the engine should work with a variable compression ratio. Although technically possible, this is not considered feasible for a low-cost product. In order to circumvent this and other losses, it was devised an innovative approach, which adopts turbocharging to allow optimum performance for different fuels, without changing compression ratio, an advance that can be added to low cost products. Alternatively, this approach can be used as an optimization tool along more conventional engines development. This advance will be implemented into a 1.3 8v FIRE FLEX MULTI-FUEL engine capable of operating with Gasoline E25, E94 ethyl hydrate, any blend of Gasoline E25 and Alcohol E94, and natural gas.

This work presents an analysis of the performance of a multi-fuel engine fuelled by gasoline, alcohol, a mixture of gasoline and alcohol and CNG. The tests are made using a four cylinder, 1.242-L, multi-fuel engine in full load, respecting the air/fuel rate established by the manufactures in the engine original calibration. In order to run with CNG, it was installed a BRC 5th generation multi-point fuel injection system. The calibration and adjustments were made using a development engine control unit for the different fuels. In this work, the performance curves are compared aiming to obtain the best relation among torque, power and specific fuel consumption for the various proposed configurations.

The new trends of the automotive market require the application of new technologies to a concept of engines, which allows for the use of different types of fuel. The multi-fuel engines available in the market display only one compression ratio, therefore being subject to optimization, as to obtain maximum efficiency the engine must work with a variable compression ratio. Although technically possible, this procedure is not considered feasible for a low-cost product. This work proposes a system, which allows for each type of fuel to attain peak efficiency through a variance in the engine intake pressure and without changing its compression ratio, a feature that can be added to a low-cost product. The gains obtained with this project will be shown in each stage of the experiment and compared to those of the original configuration of the engine. The methodology to be used is the DOE - Design of Experiment.

In this work is proposed the installation of a turbocharger in a low dislocated volume engine, aiming to achieve a higher effective mean pressure and air fuel mixture density, for a better performance of the converted engine. This analysis is made through experimental tests in a break bench, following the Brazilian standard NBR ISO 1585. The results presented shows the basic behavior of the torque curves, power and gas emission, which reflects the changes in performance with both fuels for a aspirated and turbocharged engine, for all the engine rotation speeds. These results show the technical and economical viability of the conversion to Vehicular Natural Gas of a low cc engine, when adapted a commercial turbocharger kit.