The current pollutant regulations and policies have set the need to consider the use of alternative fuels capable of complying with the emission limits still retaining appreciable engine performance. Natural gas has been considered as an effective alternative to gasoline but the drawbacks connected to its use forced the researchers to investigate into fuel additives, dual fuel solutions and innovative engine control strategies. The present work analyzes the use of hydrogen as an additive to CNG for a natural gas production engine of a C-segment vehicle and carries out a thorough investigation into the engine response over a selection of operating key points. The actual focus is set on the investigation into the vehicle as well as into the engine response and performance over driving cycles. Still, the simulation of real driving conditions would set the need to properly quantify for the effect of the hydrogen enriched blends on the full engine map over varying powers and speeds within the vehicle driving cycle. Such an approach often turns out to be too demanding in terms of time and costs and an alternative solution has been hereafter proposed by properly selecting a reduced number of operating points on the basis of the correspondent residence time and frequency over the NEDC. The selection has been performed by matching the actual engine map to the readings from the NEDC vehicle testing. Different selections have been considered and compared so as to assess for the one embedding the minimum number of working points. The key points are not meant to substitute the accomplishment of the NEDC cycle but are to be used as driving factors in the engine design so as to allow for detecting the optimal hardware and ECU configurations. The so considered engine key points have hence been extensively studied by reproducing the engine performance at the test bench and by performing a detailed heat release analysis. Different composition of the hydrogen-methane blends have been considered up to a 25% by volume of hydrogen in the mixture and specific attention has been paid to the main combustion parameters and to their optimization. As a matter of fact, such a study would allow for detecting major trends in the engine design and control strategies to compensate for the poor behavior of some of the considered points. As an example, low load and speed operations assessed for the need of a better control of the engine parameters to diminish the cylinder-to-cylinder as well as the cycle-to-cycle variability.

Development of a method for the estimation of the behavior of a CNG engine over the NEDC cycle and its application to quantify for the effect of hydrogen addition to methane operations / Baratta, Mirko; Misul, DANIELA ANNA. - In: FUEL. - ISSN 0016-2361. - STAMPA. - 140:(2015), pp. 237-249. [10.1016/j.fuel.2014.09.088]

Development of a method for the estimation of the behavior of a CNG engine over the NEDC cycle and its application to quantify for the effect of hydrogen addition to methane operations

BARATTA, MIRKO;MISUL, DANIELA ANNA
2015

Abstract

The current pollutant regulations and policies have set the need to consider the use of alternative fuels capable of complying with the emission limits still retaining appreciable engine performance. Natural gas has been considered as an effective alternative to gasoline but the drawbacks connected to its use forced the researchers to investigate into fuel additives, dual fuel solutions and innovative engine control strategies. The present work analyzes the use of hydrogen as an additive to CNG for a natural gas production engine of a C-segment vehicle and carries out a thorough investigation into the engine response over a selection of operating key points. The actual focus is set on the investigation into the vehicle as well as into the engine response and performance over driving cycles. Still, the simulation of real driving conditions would set the need to properly quantify for the effect of the hydrogen enriched blends on the full engine map over varying powers and speeds within the vehicle driving cycle. Such an approach often turns out to be too demanding in terms of time and costs and an alternative solution has been hereafter proposed by properly selecting a reduced number of operating points on the basis of the correspondent residence time and frequency over the NEDC. The selection has been performed by matching the actual engine map to the readings from the NEDC vehicle testing. Different selections have been considered and compared so as to assess for the one embedding the minimum number of working points. The key points are not meant to substitute the accomplishment of the NEDC cycle but are to be used as driving factors in the engine design so as to allow for detecting the optimal hardware and ECU configurations. The so considered engine key points have hence been extensively studied by reproducing the engine performance at the test bench and by performing a detailed heat release analysis. Different composition of the hydrogen-methane blends have been considered up to a 25% by volume of hydrogen in the mixture and specific attention has been paid to the main combustion parameters and to their optimization. As a matter of fact, such a study would allow for detecting major trends in the engine design and control strategies to compensate for the poor behavior of some of the considered points. As an example, low load and speed operations assessed for the need of a better control of the engine parameters to diminish the cylinder-to-cylinder as well as the cycle-to-cycle variability.
2015
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11583/2569137
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