A misfire detection and re-ignition control device based on an ion current signal is designed, and a method for calculating the threshold level of an ion current integral signal is proposed to judge a misfire event. Based on the combustion cycle control strategy, start-up combustion cycle misfire detection and re-ignition control are investigated in a TSDI-Two Stage Direct Injection gasoline engine using ion current signal feedback. The results show that it is feasible for the ion current integral signal to be used for misfire detection and re-ignition control. In the experiment, when the ion current integral signal is larger than the misfire threshold level ( U_misfire>0.5 V), the ion current exists in the combustion chamber, the in-cylinder fuel–air mixture combusts, and the re-ignition event cannot occur. When the ion current integral signal is smaller than the misfire threshold level ( U_misfire<0.5 V), the ion current is close to zero, the misfire event occurs, and re-ignition takes place. As far as hydrocarbon emissions are concerned, the level of unburnt hydrocarbons under successful ignition is lowest, the level of unburnt hydrocarbons under successful re-ignition is higher, and the level of unburnt hydrocarbons under unsuccessful ignition and re-ignition is the highest. Hence, the start-up combustion cycle misfire detection and re-ignition control based ion current signal feedback strategy is favorable for reducing unburnt hydrocarbon emissions.

To meet the requirements of strict fuel consumption and emission limits, continuously increasing the thermal efficiency of an internal combustion engine and decreasing its exhaust emissions are the main challenges to its sustainable development within the automotive industry. Considering the competition with other zero-emission powertrain systems, such as vehicle batteries and fuel cells, the development of the internal combustion engine needs to focus on producing higher efficiency and zero emissions to meet the request of \(\hbox {CO}_{2}\) reduction. This paper introduces two novel concepts for an internal combustion engine featuring high efficiency and zero emissions. Referred to as the argon power cycle engine fueled with either hydrogen or natural gas within an oxygen–argon mixture, its fundamentals and characteristics are expounded. This includes a method necessary to absorb carbon dioxide when natural gas is used as fuel instead of hydrogen.

For better stability of ion current employed for in-cycle combustion diagnosis and feedback control, this research develops a digital post-processing unit for in-cylinder ion current signals. Based on the processed digital ion current signal, abnormal combustion in gasoline direct injection engine is successfully detected, and the in-cycle remedy feedback control is achieved as well. Both re-ignition and re-injection are utilized for misfiring remedy, and only re-injection is employed for knocking inhibition. The accuracy of misfiring diagnosis is achieved no less than 94%, and the re-injection combined with re-ignition operation is shown to be feasible for misfiring remedy as well. The accuracy of knocking diagnosis is around 85% (knocking rate = 20%). The re-injection under the pre-knocking condition is shown to be effective for knocking inhibition.