The Impact of Injection Strategies on Emissions Reduction and Power Output of Future Diesel Engines

Experimental study of the relationship between injection rate shape and Diesel ignition using a novel piezo-actuated direct-acting injector

“…Apart of the modification in the liquid and vapor phase penetration associated with the injection rate shaping and already described in [20,21] the main differences caused by the alternative injection rate shapes concern the location and the intensity of the peak in the OH* emissions observed at the ignition (see Figure 12). Therefore, this feature on the contour map suggests that injection rate shaping affects the premixed phase of the combustion: this phase is very important because it is responsible for the peak in the rate of heat release normally observed at the ignition that causes the typical Diesel engine noise problems, and the formation of NO x [3,4]. The reduction of the intensity peak observed is an encouraging insight of the effectiveness of these injection strategies.…”

“…Summarizing, the analysis of SoOH, OH peak and M ignition reveals that none of the injection parameters has substantial effects on the ignition timing (SoOH); on the other hand, the analysis of OH peak and M ignition suggests that the introduction of injection rate shaping helps reducing the amount of heat released during the premixed phase; many studies showed that reducing the fuel burnt during this phase of the combustion brings benefits in terms of reduction of the combustion noise and NO x production [2,3].…”

“…Fuel-air mixing process, combustion and emission phenomena are necessarily linked together in direct injection Diesel engines [1][2][3][4][5]. In a scenario where the global emission standards require higher engine performances in terms of combustion efficiency and emissions reduction, all the efforts by the engine community to improve the understanding of the fuel atomization, spray development and combustion are largely justified.…”

“…Most of these systems are operated with electro-hydraulic actuation, where the fuel injector is activated using either a solenoid or a piezo-stack; however, the opening of the injector itself is produced by the pressure difference at the two sides of the needle limiting the injection control to an on-off mode. As a consequence of that, multiple injection strategies are the most employed tool to control the Diesel combustion, although they show strong limitations in minimum dwell-time, and poor atomization during the opening/closing transient [1,3].…”

Effects of hydraulic flow and spray characteristics on diesel combustion in CR direct-injection engine with indirect acting Piezo injector

“…As know, since all internal combustion engines emit incomplete combustion products that can be harmful to the environment, this increment puts higher demands on diesel engine so most automobile industry focuses on fuel injection equipment (FIE) system in the diesel engine with common-rail (CR), EGR, and turbo charger system in diesel engine to meet a more stringent vehicle emission and fuel economy regulations [1][2][3][4]. It is known that common-rail fuel injection system has needs of speed up of response and controllability of variable injection-rate for reducing diesel fuel tail-pipe emissions because high-pressure injection is easily available on the application of common-rail system.…”