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The passenger car automakers are always competing to excel in vehicle characteristics related to passenger comfort and driveability aspects. The engine calibration is a theoretical and experimental procedure with the intention to extract maximum efficiency from the engine and guarantee satisfactory levels of driving for both conventional and racing cars. This paper describes the calibration procedure of a Formula SAE race car engine. The engine was a four cylinder 600 cm3 four-strokes with modified intake and exhaust systems, controlled by an engine control unit (Motec M800 ECU). These engines present optimized characteristics for high speed, in exchange for some combustion degradation in some specific operating conditions at low speed that may impair vehicle driveability. Therefore, good tip-in reaction and the progression of the torque delivery are fundamental criteria to increase the vehicle performance, specially, to those submitted to short acceleration distances.

Ethanol with high levels of hydration is a low cost fuel that offers the potential to replace fossil fuels and contribute to lower carbon dioxide (CO2) emissions. However, it presents several ignition challenges depending on the hydration level and ambient temperature. Advanced combustion concepts such as homogeneous charge compression ignition (HCCI) have shown to be very tolerant to the water content in the fuel due to their non-flame propagating nature. Moreover, HCCI tends to increase engine efficiency while reducing oxides of nitrogen (NOx) emissions. In this sense, the present research demonstrates the operation of a 3-cylinder power generator engine in which two cylinders operate on conventional diesel combustion (CDC) and provide recycled exhaust gas (EGR) for the last cylinder running on wet ethanol HCCI combustion. At low engine loads the cylinders operating on CDC provide high oxygen content EGR for the dedicated HCCI cylinder.

Low cost ethanol with high levels of hydrations is a fuel that can be easily produced and that offers the potential to replace fossil fuels and contribute to reduce greenhouse gas emissions. However, it shows several ignition challenges depending on the hydration level, ambient temperature compression ratio and other engine-specific aspects. Advanced combustion concepts such as homogeneous charge compression ignition (HCCI) have shown to be very tolerant to the water content in the fuel due to their non-flame propagating nature. Moreover, HCCI tends to increase engine efficiency while reducing oxides of nitrogen (NOx) emissions. In this sense, the present research demonstrates the operation of a 3-cylinder power generator engine in which two cylinders operate on conventional diesel combustion (CDC) and provide recycled exhaust gas (EGR) for the last cylinder running on wet ethanol HCCI combustion.

Several motorsport competitions impose restrictions on intake systems to limit maximum engine power. Since the restriction interferes with the efficiency of the intake system as a whole, it is necessary to study ways to minimize the negative effect of changes in engine performance. In practice, the regulation imposes restrictions to the inlet air which motivates the search for the minimum pressure loss in the restrictor while maintaining an equal volumetric efficiency between the cylinders. This way, it is necessary to tune the duct lengths and diameters, and plenum volume to obtain the maximum volumetric efficiency in the most required speeds. Formula SAE competition imposes an intake system restriction of 20 mm or 19 mm diameter (for gasoline or ethanol fueled engines, respectively). Thus, to reduce pressure loss in the imposed restriction orifice, a system with a convergent divergent duct forming a venturi tube was used.