Search Results

The fuel heating system has completed a decade of operation in flex fuel vehicles to enable engine start in cold start conditions. Besides its proven-in-use benefits to reliable engine start, some recent studies have shown advantages of heating fuel also with respect to emission reduction, drivability enhancement and fuel economy. These benefits make this system a potential candidate to meet the increasingly demanding requirements of the new Brazilian emission legislation PROCONVE L7/L8. To allow system operation, not only to cold starts but whenever required, it is necessary to evaluate the system behavior under different use cases to determine the new system’s mission profile. Therefore, a multitude of tests is required to collect this data for analysis. However, performing such tests with the actual system can be very costly and time-consuming, due to the high variance of test parameters, such as engine sizes, fuel blends, emission driving cycles, ambient temperature, etc.

Many software functions currently available in the engine control units have been developed for several years (decades in some cases), reengineered or adapted due to new requirements, what may add to their inherent complexity an unnecessary complication. This paper deals with the study and implementation of a software reengineering strategy for the embedded domain, which is in transfer from research department to product development, here applied to improve maintainability of flex fuel functions. The strategy uses the SCODE “Essential Analysis”, an approach for the embedded system domain. The method allows to reduce the system complexity to the unavoidable inherent problem complexity, by decomposing the system into smaller sub problems based on its essential physics. A case study was carried out to redesign a function of fuel adaptation. The analysis was performed with the support of a tool, which covers all the phases of the method.

The first generation of heated cold start systems for flex fuel vehicles in Brazil were launched in 2009 and have solved most of the issues around the former gasoline sub-tank concept. This new technological approach focused on concerns like the user experience by having the need to fulfill the sub-tank, on complains related to possible old gasoline left inside, in the complexity of the electro mechanic nozzles and other possible improvements. Some years later, the second generation expanded the initial cold start application to a mature drivability enhancement and further possibility of usage as a support for emission reduction. A leaner electronic control and heat sink concept also represented an alternative to the first generation, and an engineered plastic fuel rail replaced the first metallic concept, which was an option to the initial concerns about the combination of high temperatures and fuel.

The growing concerns with pollution emissions, the uncertain future about the availability of fossil fuels and the recent advances in battery technology put the electrical powertrain development forward. Hybrid and electric vehicles have already become reality and they are gaining more space in the market. Electrical motors have a peculiar characteristic: differently from combustion engines, their peak torque is already available at 0 rpm. Therefore, it is possible to obtain a much better acceleration response, in comparison to a combustion engine with similar power. Considering that, the objective of this project is to adapt the entire electric powertrain of a passenger car into a kart. Technologies of electronic control module, motor, inverter and battery are among the most advanced currently available and they may take the vehicle to 0-100 km/h acceleration results comparable to supersport cars.

Anyone who already had the opportunity to ride a bike has experienced the benefits of a system operating at coasting: As soon as a certain velocity is reached, the biker stops pedaling and just coasts down, administering the kinetic energy to minimize his own energy consumption. The idea, inspired by biking, that it is possible to improve fuel economy just by adopting clever coasting strategies suggests also a very promising perspective in the automotive world and, as a matter of fact, is not a really “new” thing: It has already been explored in the past on several different vehicle models. Unfortunately it has not been able to establish itself “de facto” in the market, probably due to the difficulty in conciliating the available technical solutions of the time to the extensive list of requirements imposed by automotive industry.

The analysis of the air motion inside the cylinders of an internal combustion engine constitutes a very important step during engines design. It is already known that its movement, normally decomposed in tumble and swirl motion, is totally related to the majority of phenomena which occur inside cylinder, like fuel evaporation, mixture formation or flame propagation. The use of mechanical devices in the intake system represents an interesting option in the attempt of optimizing the airflow and finding the best condition for maximum power and minimum specific fuel consumption. Devices like flow boxes, which control the airflow and change its main characteristics before entering the cylinder, by obstructing the air and changing its directions, are one possibility. Based on this idea, this paper presents a numerical analysis of the utilization of a flow box in the intake system of a spark ignition engine.

This article aims at discussing the impacts of using the rapid prototyping tool ASCET in the software development process. Our experience shows that there is a growing demand from Brazilian customers for participation in the development of specific functions. However, following the traditional V-model for software development until the generation of production code can be very time-consuming and costly, especially if we think of complex functions that might need several design iterations until the final customer acceptance. In order to overcome this situation we have introduced in our teamwork the rapid prototyping concept together with automatic production code generation.

The identification of fuel blends using software strategies and the oxygen sensor are widely known for flex fuel and naturally aspirated engines in Brazil, since its first launch in 2003. It represents a cost effective alternative to identify the ethanol content in the fuel, which is being used in the combustion, with an accurate performance and reduced complexity. With the introduction of flex fuel vehicles equipped with turbocharger, especially the ones with Direct Injection (DI) technology, an ethanol sensor as an additional product has been used so far to identify the ethanol content in the fuel blend. Such engine types may be more sensitive to fuel mixture deviations, since it works with higher loads, more combustion chamber pressure and an extended temperature range in comparison with the normally aspirated applications. Due to these reasons, worst-case scenarios with high ethanol content deviation could cause damage to the engine and exhaust hardware.