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Experimental aviation engines face numerous challenges, including the need for energy efficiency, alternative fuel sources, reduced weight and size, greater durability with reliability, emissions reduction, and integration with advanced control and monitoring systems. This study presents the performance of a two-stroke engine with a Uniflow scavenging system with a flathead valve concept, with lower specific fuel consumption than conventional two-stroke aircraft engines. The engine’s maximum speed is limited to 3000 rpm for better cylinder scavenging efficiency, which also eliminates the need for a reduction gearbox, simplifies the design, and reduces the engine’s total mass. 1D simulations were conducted to evaluate combustion and performance parameters using aviation.

Stringent emission legislations have pushed engine operation to borderline knock. Knocking combustion limits engine efficiency, putting a threshold in carbon emission reduction that impairs further decarbonization of the transport sector. In this way, online knock monitoring is very important during engine development and calibration to allow operation with higher efficiency levels. Commonly, knock detection methods require complex calculations with high computational cost. Furthermore, these methods normally need previous calibration of a threshold value for each specific engine to indicate the knock limit, requiring important engineering resources and time. Hence, this paper proposes a novel methodology for knock detection that is simple, does not require prior calibration and can be used for sensorless knock detection. The method is applied by relating the crank angle of maximum pressure rise rate (AMPRR) with the angle of 50% of fuel mass burned (CA50), the so-called G Index (GI).

The prediction of ignition delay times is very useful during the development phase of internal combustion engines. When it comes to biofuels such as ethanol and its blends with gasoline, its importance is enhanced, especially when it comes to flex-fuel engines and the need to address current and future emissions legislations and efficiency goals. The ignition delay time measured as the angular difference between the spark discharge time, as commanded by the ECU and a relevant fraction of fuel mass burned (usually, 2, 5 or 10%). Experimental tests were performed on a downsized state-of-the-art internal combustion engine. Engine speed of 2500 rpm, with load of 6 and 13 bar IMEP were set for investigation. Stoichiometric operation and MBT or knock-limited spark timings were used, while valve overlap was varied, in order to address the effects of scavenging and residuals on ignition delay times.

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.

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.

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.

The possibility to vary compression ratio offers a new degree of freedom that may enable so far not exploited benefits for the combustion process especially for highly boosted spark ignited engines. Numerous approaches to enable a variable compression ratio (VCR) have been tried and tested in the past. Nevertheless, none of these systems reached series production because of several reasons, ranging from too much complexity and moveable parts to deep modification required on existing engine architectures and manufacturing lines. Instead, the approach of a variable length conrod (VCR conrod) could be the solution for integration in almost any type of engine with minor modifications. It is then considered by several OEMs as a promising candidate for midterm series production. This paper shows, firstly, a discussion of the benefits of a variable compression ratio system.

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.

In many vehicle motorsport categories, the one of the most important factors that lead a team to the victory is the suspension setup. Parameters like roll stiffness and camber changing are essential to the vehicle behavior during a driving situation. To handle these variables, features like suspension hardpoints arrangement, pivot points position and spring stiffness can be settled. However a setup only will perform a desirable effect if the chosen configuration does not change. Ideally, to make it possible, every component that holds suspension loads (suspension members, mounting plates and chassis) would have to be infinitely rigid. Even though it is not achievable, the existing deformation can be small enough to be negligible when compared with suspension displacement. In order to reach this target, this paper introduce a spring modeling and a Finite Element multibody modeling process of a Formula SAE prototype’s suspension and chassis.

In the way of achieving maximum performance of a racecar several aspects of it have to be optimized. The whole picture of vehicle performance involves crossing data to find relationship among systems and identifying trends, pitfalls and optimum points. In this paper, a straightforward software tool for tire data analysis is developed and described. The software aims to integrate tire data analysis in early stages of the development process of a Formula SAE racecar. In addition, it is thought to be a learning environment to fresh team members. To establish and achieve the necessary goals, an affordancebased model was used to elicit user needs. Regarding the tires, it was possible to precisely point out what data is required to quickly fit a Pacejka tire mode and to cross raw tire data of different tires and preview the steady state balance of a vehicle.

Renewable fuels have received more attention in the last few decades since the fuel demand is constantly increasing. In this scenario, fuels from vegetable oils are emerging as an interesting alternative. In this study, biodiesel produced from used cooking oil was studied. Several concentrations of biofuel were tested to evaluate their performance and combustion characteristics i.e. 7% (B07), 17% (B17), 27% (B27), 52% (B52), 77% (B77) and 100% by volume of Biodiesel (B100) on conventional diesel. Tests were conducted in a single cylinder four-stroke compression ignition engine. A 1-D computational model was built and compared to experimental results. The biodiesel concentration in the blends had influence on engine performance by increasing fuel consumption due to its reduced lower heating value. In addition, larger fractions of biodiesel on conventional diesel presented higher peak of heat release.

In the present paper, a typical Formula SAE double-wishbone suspension is discussed. This study aims to point out a preliminary chassis setup to reduce testing time on track and improve the overall performance of a prototype in a Formula SAE Skid Pad event. The influence of kinematic parameters of the suspension are analyzed to quantify how they change the capability of the tire to generate lateral force due to camber effects. To enhance results, special attention is given to a Magic Formula tire model based on a constrained forces and moments tire test data. Camber and Ackermann steering geometry showed up as major tuning tools to attempt during test period.

This study evaluates the performance of an ethanol fueled spark ignited engine running with high levels of hydration. Ethanol is a renewable fuel and has been considered a promising alternative to counteract global warming and to reduce pollutant emissions. Its use is well established in ICE as the main fuel or blended with gasoline. However, due to its lower calorific value, it shows increased fuel consumption when compared to gasoline, rendering its use sometimes less attractive. The energy demand to produce ethanol, especially at the distillation phase, increases exponentially as the concentration of ethanol-in-water goes from 80% onwards. Thus, mixtures with less than 80% of ethanol-in-water would reduce the energy consumption during production, yielding a less expensive fuel. In previous studies, to evaluate the feasibility of wet ethanol as a fuel for spark-ignited engines, results have shown that it was possible to use mixtures of up to 40% of water-in-ethanol.

The aim of this paper is to show that the gains, technical and/or economical, from the use of ethanol as fuel in agricultural aviation may be even greater if the aircraft engine is specially designed for that purpose. A specific design is also necessary if it is intended to achieve a truly "green" engine, neutral regarding carbon emissions. Using available technologies, computational tools, development methods and project management methods (Reference Model for Agricultural Machinery Development Process (RM-AMDP), the engine can be fully developed to be used specifically as an agricultural aircraft propellant operating with ethanol. In Brazil, the current fleet of agricultural airplanes has around 1500 aircrafts and almost all operating with AvGas (Aviation Gasoline). There is already in Brazil a "green" airplane, manufactured by Neiva, a subsidiary of the aircraft manufacturer Embraer. This model uses a conversion kit on the original engine to use ethanol as fuel.

Emerging markets and South America in particular, have quickly become the cornerstone of major automotive companies in recent years. Currently, all major players are located in the region, and this has created an excellent environment for developing market-tailored products. The trend in the design and technology community is one which allows the final customer to improve his own safety and reduce overall power consumption. Throughout the entire automotive industry, the lighting system has always had a very important role to play during its long history. In the past 50 years, vehicular lighting has achieved an important status due to its close relationship by enhancing passenger and vehicle security. In addition, there is still room for improvement in the halogen front lighting system. Particularly, it is of utmost importance to highlight the implementation of NEO (new efficient optics).

Controlled Auto-Ignition (CAI) also known as Homogeneous Charge Compression Ignition (HCCI) is increasingly seen as a very effective way of lowering both fuel consumption and emissions. Hence, it is regarded as one of the best ways to meet stringent future emissions legislation. It has however, still many problems to overcome, such as limited operating range. This combustion concept was achieved in a production type, 4-cylinder gasoline engine, in two separated tests: naturally aspirated and turbocharged. Very few modifications to the original engine were needed. These consisted basically of a new set of camshafts for the naturally aspirated test and new camshafts plus turbocharger for the test with forced induction. After previous experiments with naturally aspirated CAI operation, it was decided to investigate the capability of turbocharging for extended CAI load and speed range.

Controlled Auto-Ignition (CAI), also known as HCCI (Homogeneous Charge Compression Ignition), is increasingly seen as a very effective way of lowering both fuel consumption and emissions from gasoline engines. Therefore, it's seen as one of the best ways to meet future engine emissions and CO2 legislations. This combustion concept was achieved in a Ford production, port-injected, 4 cylinder gasoline engine. The only major modification to the original engine was the replacement of the original camshafts by a new set of custom made ones. The CAI operation was accomplished by means of using residual gas trapping made possible by the use of VCT (variable cam timing) on both intake and exhaust camshafts. When running on CAI, the engine was able to achieve CAI combustion with in a load range of 0.5 to 4.5 BMEP, and a speed range of 1000 to 3500 rpm. In addition, spark assisted CAI operation was employed to extend the operational range of low NOx and low pumping loss at part-load conditions.