TY - JOUR
T1 - The Potential of Gasoline Fueled Pre Chamber Ignition Combined with Elevated Compression Ratio
AU - Stadler, Andreas
AU - Sauerland, Henning
AU - Härtl, Martin
AU - Wachtmeister, Georg
N1 - Publisher Copyright:
© 2020 SAE International. All Rights Reserved.
PY - 2020/4/14
Y1 - 2020/4/14
N2 - Pre-chamber ignition is a method to simultaneously increase the thermal efficiency and to meet ever more stringent emission regulations at the same time. In this study, a single cylinder research engine is equipped with a tailored pre-chamber ignition system and operated at two different compression ratios, namely 10.5 and 14.2. While most studies on gasoline pre-chamber ignition employ port fuel injection, in this work, the main fuel quantity is introduced by side direct injection into the combustion chamber to fully exploit the knock mitigation effect. Different pre-chamber design variants are evaluated considering both unfueled and gasoline-fueled operation. As for the latter, the influence of the fuel amount supplied to the pre-chamber is discussed. Due to its principle, the pre-chamber ignition system increases combustion speeds by generating enhanced in-cylinder turbulence and multiple ignition sites. This property proves to be an effective measure to mitigate knocking effects. It is shown that less spark retard compared to conventional spark ignition allows to exploit the efficiency benefit of elevated compression ratios also in high load operation for stoichiometric mixtures. Furthermore, auxiliary fueling of the pre-chamber enables ultra-lean combustion (λ=2.0) with very low NOx emission levels. Apart from decreased throttling losses lean burn assists to further suppress knocking in case of elevated compression ratios. Finally, it is demonstrated that the combination of ultra-lean combustion and elevated compression ratio leads to a significant improvement of the indicated efficiency with peak values of about 43 %. Higher PN emissions in low load and increased heat losses remain challenges of the used pre-chamber ignition system.
AB - Pre-chamber ignition is a method to simultaneously increase the thermal efficiency and to meet ever more stringent emission regulations at the same time. In this study, a single cylinder research engine is equipped with a tailored pre-chamber ignition system and operated at two different compression ratios, namely 10.5 and 14.2. While most studies on gasoline pre-chamber ignition employ port fuel injection, in this work, the main fuel quantity is introduced by side direct injection into the combustion chamber to fully exploit the knock mitigation effect. Different pre-chamber design variants are evaluated considering both unfueled and gasoline-fueled operation. As for the latter, the influence of the fuel amount supplied to the pre-chamber is discussed. Due to its principle, the pre-chamber ignition system increases combustion speeds by generating enhanced in-cylinder turbulence and multiple ignition sites. This property proves to be an effective measure to mitigate knocking effects. It is shown that less spark retard compared to conventional spark ignition allows to exploit the efficiency benefit of elevated compression ratios also in high load operation for stoichiometric mixtures. Furthermore, auxiliary fueling of the pre-chamber enables ultra-lean combustion (λ=2.0) with very low NOx emission levels. Apart from decreased throttling losses lean burn assists to further suppress knocking in case of elevated compression ratios. Finally, it is demonstrated that the combination of ultra-lean combustion and elevated compression ratio leads to a significant improvement of the indicated efficiency with peak values of about 43 %. Higher PN emissions in low load and increased heat losses remain challenges of the used pre-chamber ignition system.
UR - http://www.scopus.com/inward/record.url?scp=85083829035&partnerID=8YFLogxK
U2 - 10.4271/2020-01-0279
DO - 10.4271/2020-01-0279
M3 - Conference article
AN - SCOPUS:85083829035
SN - 0148-7191
VL - 2020-April
JO - SAE Technical Papers
JF - SAE Technical Papers
IS - April
T2 - SAE 2020 World Congress Experience, WCX 2020
Y2 - 21 April 2020 through 23 April 2020
ER -