Riassunto analitico
More stringent pollutant emissions limits and CO2 emissions reduction policies are forcing the automotive industry toward a cleaner and decarbonized way of transportation.
The goal is to achieve carbon-neutrality within 2050 and limit global warming to 2 °C (possibly 1.5 °C) with respect to pre-industrial levels as stated in both the European Green Deal and the Paris Agreement and further reiterated at the COP26.
With the aim of simultaneously reducing both pollutant and CO2 emissions a lot of research is currently carried out on low temperature highly efficient combustions (LTC).
Among these advanced combustions, one of the most promising is called Gasoline Compression Ignition (GCI) and it is based on the compression ignition of a gasoline-like fuel. Nevertheless, despite GCI proved to be effective in reducing both pollutants and CO2 emissions, GCI combustion management represents the main challenge which hinders the diffusion of this methodology for transportation.
Several works in literature demonstrated that to properly control GCI combustion, a multiple injections strategy is needed. By the rise of pressure and temperature generated by the spontaneous ignition of small amount of fuel early injected, the ignition delay of the following main injection burns with a near zero ignition delay and, therefore, torque production. Since the combustion of the pre-injections is chemically driven, their ignition delay might be affected by a slight variation of the engine control parameters and, consequently, generate misfire or knocking.
The goal of this work was to build a control-oriented 0-D ignition delay model to be used to properly phase the injection pattern. For any recorded cycle, the ignition delay was evaluated as the time elapsed from the crank angle in which the first pilot injection occurs to the start of combustion.
After an accurate analysis of the quantities affecting the ignition delay, it was decided to model the ignition delay as a function of both a thermodynamic and a chemical-physical variable. The comparison between measured and modelled ignition delay shows a good accuracy (the error in estimating the start of combustion is less than 5 deg.) over a wide range of operating conditions. Therefore, by the accuracy in the ignition delay estimation, the presented model can be considered as feed-forward model-based contribution for control purposes.
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Abstract
More stringent pollutant emissions limits and CO2 emissions reduction policies are forcing the automotive industry toward a cleaner and decarbonized way of transportation.
The goal is to achieve carbon-neutrality within 2050 and limit global warming to 2 °C (possibly 1.5 °C) with respect to pre-industrial levels as stated in both the European Green Deal and the Paris Agreement and further reiterated at the COP26.
With the aim of simultaneously reducing both pollutant and CO2 emissions a lot of research is currently carried out on low temperature highly efficient combustions (LTC).
Among these advanced combustions, one of the most promising is called Gasoline Compression Ignition (GCI) and it is based on the compression ignition of a gasoline-like fuel. Nevertheless, despite GCI proved to be effective in reducing both pollutants and CO2 emissions, GCI combustion management represents the main challenge which hinders the diffusion of this methodology for transportation.
Several works in literature demonstrated that to properly control GCI combustion, a multiple injections strategy is needed. By the rise of pressure and temperature generated by the spontaneous ignition of small amount of fuel early injected, the ignition delay of the following main injection burns with a near zero ignition delay and, therefore, torque production. Since the combustion of the pre-injections is chemically driven, their ignition delay might be affected by a slight variation of the engine control parameters and, consequently, generate misfire or knocking.
The goal of this work was to build a control-oriented 0-D ignition delay model to be used to properly phase the injection pattern. For any recorded cycle, the ignition delay was evaluated as the time elapsed from the crank angle in which the first pilot injection occurs to the start of combustion.
After an accurate analysis of the quantities affecting the ignition delay, it was decided to model the ignition delay as a function of both a thermodynamic and a chemical-physical variable. The comparison between measured and modelled ignition delay shows a good accuracy (the error in estimating the start of combustion is less than 5 deg.) over a wide range of operating conditions. Therefore, by the accuracy in the ignition delay estimation, the presented model can be considered as feed-forward model-based contribution for control purposes.
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