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The optimization of turbocharging systems for automotive applications has become crucial in order to increase engine performance and meet the requirements for pollutant emissions and fuel consumption reduction. Unfortunately, performing an optimal turbocharging system control is very difficult, mainly due to the fact that the flow through compressor and turbine is highly unsteady, while only steady flow maps are usually provided by the manufacturer. For these reasons, one of the most important quantities to be used onboard for optimal turbocharger system control is the rotational speed fluctuation, since it provides information both on turbocharger operating point and on the energy of the unsteady flow in the intake and exhaust circuits. This work presents a methodology that allows determining the instantaneous turbocharger rotational speed through a proper frequency processing of the signal coming from one accelerometer mounted on the turbocharger compressor.

Knocking combustions heavily influence the efficiency of Spark Ignition engines, limiting the compression ratio and sometimes preventing the use of Maximum Brake Torque (MBT) Spark Advance (SA). A detailed analysis of knocking events can help in improving the engine performance and diagnostic strategies. An effective way is to use advanced 3D Computational Fluid Dynamics (CFD) simulation for the analysis and prediction of the combustion process. The standard 3D CFD approach based on RANS (Reynolds Averaged Navier Stokes) equations allows the analysis of the average engine cycle. However, the knocking phenomenon is heavily affected by the Cycle to Cycle Variation (CCV): the effects of CCV on knocking combustions are then taken into account, maintaining a RANS CFD approach, while representing a complex running condition, where knock intensity changes from cycle to cycle.

Gasoline engines can be affected, under certain operating conditions, by knocking combustions: this is still a factor limiting engines performance, and an accurate control is required for those engines working near the knock limit, in order to avoid permanent damage. HCCI engines also need a sophisticated combustion monitoring methodology, especially for high BMEP operating conditions. Many methodologies can be found in the literature to recognize potentially dangerous combustions, based on the analysis of the in-cylinder pressure signal. The signal is usually filtered and processed, in order to obtain an index that is then be compared to the knock threshold level. Thresholds setting is a challenging task, since usually indexes are not intrinsically related to the damages caused by abnormal combustions events. Furthermore, their values strongly depend on the engine operating conditions (speed and load), and thresholds must therefore vary with respect to speed and load.

This paper describes the development of a mathematical model which allows the simulation of the Internal Combustion Engine (ICE), the transmission and the vehicle dynamics of a motor vehicle equipped with a Continuously Variable Transmission (CVT) system. The aim of this work is to realize a simulation tool that is able to evaluate the performance and the operating conditions of the ICE, once it is installed on a given vehicle. Since the simulation has to be run in real-time for Hardware In the Loop (HIL) applications, a zero-dimensional (filling and emptying) model is used for modeling the cylinder thermodynamics and the intake and exhaust manifolds. The combustion is modeled by means of single zone model, with the fuel burning rate described by Wiebe functions. The gas proprieties depend on temperature and chemical composition of the gas, which are evaluated at each crank-angle.

To establish a fair competition between racing vehicles is not an easy task, if different types of engine are allowed to participate (within the same class). In the Motorsports world there are several Championships where the regulations leave to the project manager substantial freedom in the vehicle-engine layout definition: The 2002 World Offshore Class I Championship (WOCC) seems to be an excellent example, since both gasoline and diesel (naturally aspirated and turbocharged) engines are admitted to race. The paper presents a power output comparison method that could be useful both for the organizers to establish a fair competition as well as for the racing engineers to decide what's the optimal layout. Since the analysis regards the maximum power, BMEP and engine speed have to be evaluated under such condition for the engines to be compared.

The continuous development of modern Internal Combustion Engine (ICE) management systems is mainly aimed at complying with upcoming increasingly stringent regulations throughout the world. Performing an efficient combustion control is crucial for efficiency increase and pollutant emissions reduction. These aspects are even more crucial for innovative Low Temperature Combustions (such as RCCI), mainly due to the high instability and the high sensitivity to slight variations of the injection parameters that characterize this kind of combustion. Optimal combustion control can be achieved through a proper closed-loop control of the injection parameters. The most important feedback quantities used for combustion control are engine load (Indicated Mean Effective Pressure or Torque delivered by the engine) and center of combustion (CA50), i.e. the angular position in which 50% of fuel burned within the engine cycle is reached.

In order to reduce both polluting emissions and fuel costs, many countries allow mixing ethanol to gasoline either in fixed percentages or in variable percentages. The resulting fuel is labeled E10 or E22, where the number specifies the ethanol percentage. This operation significantly changes way the stoichiometric value, which is the air-to-fuel mass ratio theoretically needed to completely burn the mixture. Ethanol concentration must be correctly estimated by the Engine Management System to optimally control exhaust emissions, fuel economy and engine performance. In fact, correct fuel quality recognition allows estimating the actual stoichiometric value, thus allowing the catalyst system to operate at maximum efficiency in any engine working point. Moreover, also other essential engine control functions should be adapted in real time by taking into account the quality of the fuel that is being used.

While the Diesel Particulate Filter (DPF) is actually a quasi-standard equipment in the European Diesel passenger cars market, an interesting solution to fulfill NOx emission limits for the next EU 6 legislation is the application of a Selective Catalytic Reduction (SCR) system on the exhaust line, to drastically reduce NOx emissions. In this context, one of the main issues is the performance of the SCR system during cold start and warm up phases of the engine. The exhaust temperature is too low to allow thermal activation of the reactor and, consequently, to promote high conversion efficiency and significant NOx concentration reduction. This is increasingly evident the smaller the engine displacement, because of its lower exhaust system temperature (reduced gross power while producing the same net power, i.e., higher efficiency).

In the past years, stringent emission regulations for Internal Combustion (IC) engines produced a large amount of research aimed at the development of innovative combustion methodologies suitable to simultaneously reduce fuel consumption and engine-out emissions. Previous research demonstrates that the goal can be obtained through the so-called Low Temperature Combustions (LTC), which combine the benefits of compression-ignited engines, such as high compression ratio and unthrottled lean operation, with a properly premixed air-fuel mixture, usually obtained injecting gasoline-like fuels with high volatility and longer ignition delay. Gasoline Partially Premixed Combustion (PPC) is a promising LTC technique, mainly characterized by the high-pressure direct-injection of gasoline and the spontaneous ignition of the premixed air-fuel mixture through compression, which showed a good potential for the simultaneous reduction of fuel consumption and emissions in CI engines.

Gasoline engines can be affected, under certain operating conditions, by knocking combustions, which can result in serious engine damage. Specific power and efficiency are influenced by factors such as compression ratio and spark advance regulation, that modify the combustion development over the crank angle: the trade-off between performance and the risk of irreversible damages is still a key factor in the design of both high-performance (racing) and low-consumption engines. New generation detection systems, especially based on ionization current technology, allow aggressive advance mapping and control, and future equipment, such as low-cost in-cylinder pressure transducers, will allow following that trend. Also HCCI (Homogeneous Charge Compression Ignition) engines need a sophisticated combustion monitoring methodology, since increasing BMEP levels in HCCI mode force the combustion to approach the knocking operation.