Control-oriented “crank-angle” based modeling of automotive engines.

It is well known that in automotive applications problems related to control and management are nowadays of paramount importance to improve engine performance and to reduce fuel consumption and pollutant emissions. In the design of control and diagnostics systems the use of theoretical models proved to be very promising, also to reduce development time and costs, as widely documented in the open literature. From this point of view, the complexity of actual engines due both to the continuous enhancement of existing subsystems (e.g., turbochargers, exhaust gas recirculation systems, aftertreatment components, etc.) and to the introduction of specific devices (e.g., Variable Valve Actuation systems) give rise to challenging issues in modelling development and applications. The paper describes a theoretical model of an automotive engine built up starting from the original library developed in Simulink® by the authors for the simulation of last generation automotive engines. The tool was used in former works to build up Mean Value Models (MVMs) of automotive engines for “real-time” simulations, which were used in Hardware-in- the-Loop (HiL) applications. The model proposed in this work is an enhancement of the mentioned ones to allow for “crank-angle” simulations of engine thermodynamic processes. To this extent several blocks were built up for the simulation of intake and exhaust valves (with user-defined lift curves and variable actuation) and of in-cylinder processes. Combustion process has been described following a classic single-zone approach based on a proper Heat Release Rate (HRR). Other components of the intake and exhaust systems were modelled by using the original library blocks. Through a specific calibration procedure, the model was fitted on the typical layout of an automotive SI engine Copyright © 2011 SAE International doi:10.4271/2011-24-0144 allowing for steady and transient simulations of the engine behaviour. Calculated results are compared in the paper with available experimental data, showing a good agreement

Nuove prospettive europee per una mobilità sostenibile.

La mobilità è un aspetto fondamentale nello sviluppo futuro dell’economia e della tutela ambientale. Al pari dell’energia e dell’acqua, la mobilità di persone e merci risulta un’esigenza ormai acquisita, che deve consentire una evoluzione sostenibile e socialmente accettabile. Il tema della mobilità è strettamente legato a quello dell’energia ed in questo settore la Commissione Europea risulta da tempo impegnata, nello sviluppo di strategie di lungo termine. In particolare queste politiche, finalizzate a ridurre progressivamente l’impatto sull’ambiente delle diverse attività che utilizzano energia, si propongono di conseguire il target di una riduzione del 20% delle emissioni di GHG (Green House Gases), e specificatamente della CO2, entro il 2020 sviluppando al tempo stesso le strategie per un percorso di più lungo termine: ci si propone infatti un traguardo ambizioso, ovvero la riduzione delle emissioni globali EU di GHG tra l’80% ed il 95% entro il 2050. Tale obiettivo viene distribuito in modo pesato tra i diversi settori “energivori”, anche in funzione dei costi previsti per le diverse modalità e tecnologie di intervento. In questo ambito la conseguente riduzione nelle emissioni di GHG per il settore dei trasporti sul lungo periodo si può stimare intorno al 60%

Dynamic model of a combined ICE (Internal Combustion Engine) – ORC (Organic Rankine Cycle) power unit.

It is nowadays well known that ORC systems can represent a very interesting way to recover thermal power discharged by other power generating units when the use of thermal power as such is not possible. Many examples can be found in Italy and other countries where the existence of incentives for electrical power generation by stationary ICEs fed using biomasses (such as biogas, vegetable oils and others) makes the operation of these systems feasible even if the heat is totally wasted. As shown in previous works by the authors and in other works available in the open literature ORCs can recover a significant amount of the thermal power available from a stationary engine converting it into electrical power with the effect of increasing the overall generating efficiency. A good matching of these two systems and the correct design of components such as evaporator and turbine for the ORC are however requested. Also a proper selection of the fluid to be employed within the ORC is crucial to enhance the overall benefits. After briefly describing the models of ICE and ORC, the full ICE-ORC combined plant layout is created in the Simulink® environment and used to run simulations under transient operating conditions as well as ICE off design conditions, showing the flexibility and usability of the realized simulation tool for design purposes

A method for diesel combustion simulation in a “real-time” engine model for control applications.

It is well known that in automotive applications problems related to control and management are nowadays of paramount importance to improve engine performance and to reduce fuel consumption and pollutant emissions. In the design of control and diagnostics systems the use of theoretical models proved to be very promising, also to reduce development time and costs, as widely documented in the open literature. From this point of view, the complexity of present engines due both to the continuous enhancement of existing subsystems (e.g., turbochargers, exhaust gas recirculation systems, aftertreatment components, etc.) and the introduction of specific devices (e.g., Variable Valve Actuation systems) give rise to challenging issues for modelling development and application. The paper describes a theoretical model of a turbocharged automotive engine built up starting from the original library developed in Simulink® by the authors for the simulation of last generation automotive engines. The tool was used in former works to build up Mean Value Models (MVMs) of automotive Diesel engines suitable for “real-time” simulations and therefore used in several HiL applications [6]. The model proposed in this work is an enhancement of the mentioned ones and it has been developed in order to allow for a “crank-angle” simulation of the engine. To this extent several block were built up for the simulation of intake and exhaust valves (with user-defined lift curves and variable actuation) and of in-cylinder processes. Combustion process has been described following a classic single-zone approach based on a proper Heat Release Rate (HRR). The library blocks were used to model other components of the intake and exhaust system. Through a specific calibration procedure, the model was fitted on a typical layout of an automotive Diesel engine allowing for transient simulation of the engine behaviour. Calculated results are compared in the paper with experimental data measured on a test bench, showing a good agreement both in steady and transient operating conditions