Investigation of the potential of corona ignition to control gasoline homogeneous charge compression ignition combustion

Abstract

A complex task regarding the control of the homogeneous charge compression ignition (HCCI) combustion process is the control of combustion timing, represented by the crank angle at which 50 per cent of the fuel mass inside the cylinder is burned (MFB50). The most important parameters for transient MFB50 control are the mass of (hot) residual gas inside the cylinder (e.g. retained by internal exhaust gas recirculation), the injection strategy (in the case of direct fuel injection), and the spark timing. In this paper, the potential of a corona ignition system is examined in comparison with a conventional spark ignition system for the HCCI combustion process. For this purpose, thermodynamic investigations have been carried out on a single-cylinder research engine, combined with one-dimensional gas exchange analyses and high-speed visualization of combustion in a transparent engine. It could be demonstrated that both ignition systems are capable of influencing the autoignition process. The corona ignition system, however, allows a much later ignition point for achieving the same MFB50. This is due to the spatial character of the initial ignition area of corona ignition. In addition, the corona ignition system is more robust with respect to a change in the boundary conditions, such as a variation in the residual gas rate or the mixture composition. It is therefore more reliable in initiating autoignition, even in critical operating conditions. Additionally, it was found that the corona ignition system permits the combustion to be influenced by means of a variation in the ignition energy, which appeared to be not the case for the conventional ignition system.

Future gasoline engine ignition: A review on advanced concepts

“…The RF energy can be efficiently delivered to the discharge tips only if the system is optimally tuned, including treating the cylinder charge as a part of the electric circuit-a virtual capacitor. According to the publicized results, 51,[81][82][83][84][85][86][87][88][89][90][91][92][93] to date, the leading contenders for RF corona ignition prototyping includes the advanced corona ignition system (ACIS) by Federal Mogul and the Ecoflash corona ignition system by BorgWarner. One of the challenges of RF corona ignition is ensuring the inception of corona discharge while avoiding arc touchdown, especially in high-density conditions when a higher voltage is demanded.…”

“…88 Suess investigated the potential of corona ignition to assist the control of gasoline HCCI combustion, compared with the results of conventional spark assistance. 51 The controllability of the ignition assistance on the HCCI combustion phasing is shown in Figure 28. Both spark and corona ignition demonstrated the ability to assist better phasing the HCCI combustion by varying the energizing timing ahead of the auto-ignition timing.…”

An Optical Method to Characterize Streamer Variability and Streamer-to-Flame Transition for Radio-Frequency Corona Discharges

“…These advantages are related to the three combustion enhancement pathways: thermal, kinetic, and transport [17]. Among all the LTP systems, RF corona was intensively studied in recent years [18][19][20][21], especially in optical engines [11,14,22], to characterize its ability to speed up the early flame kernel generation [15].…”

The effect of advanced ignition system on gasoline low temperature combustion

“…While majority of these systems were evaluated for dilute stoichiometric combustion and lean homogeneous applications, low-temperature plasma systems were explored for achieving advanced combustion strategies like lean stratified-charge combustion and lean homogeneous charge compression ignition (HCCI). 8–10…”