A Novel Air and EGR Emulation Facility for the Optimisation of the Powertrain Architecture

Author(s):  
Simon Orchard ◽  
Umud Ozturk ◽  
Nick Evans ◽  
Tomasz Duda ◽  
Ed Chappell ◽  
...  

Abstract In this work, an external air and EGR emulation facility has been designed that can replicate a wide range of boosting and EGR delivery systems to a multi-cylinder engine platform. The facility works by removing the incumbent air path and replacing it with externally boosted fresh air that is conditioned using a transient flow and temperature controller. The facility also recycles the actual exhaust gases from the engine whilst removing the constraints of required pressure differences to drive this flow. The resulting system is able to control the boundary conditions of intake air flow - pressure and temperature, engine back-pressure and EGR flow rate independently. Three testing approaches have been described that allow to obtain valuable data across a wide range of the engine map (based on an example of a 1.0L direct injection gasoline engine) also beyond its typical hardware related limits. The facility is designed to be used as part of an engine design optimisation process. The facility generates data of the engine combustion system independently of the associated air path subsystems and excites the boundary conditions beyond those that would be expected from a specific air path design. The data is then used to populate 1D engine models which can be confidently used to predict the performance of a specific air path hardware combination and control strategy.

Author(s):  
Dmitrii Mamaikin ◽  
Tobias Knorsch ◽  
Philipp Rogler ◽  
Philippe Leick ◽  
Michael Wensing

Gasoline Direct Injection (GDI) systems have become a rapidly developing technology taking up a considerableand rapidly growing share in the Gasoline Engine market due to the thermodynamic advantages of direct injection. The process of spray formation and propagation from a fuel injector is very crucial in optimizing the air-fuel mixture of DI engines. Previous studies have shown that the presence of some cavitation in high-pressure fuel nozzles can lead to better atomization of the fluid. However, under some very specific circumstances, high levels of cavitation can also delay the atomization process; spray stabilization due to hydraulic flip is the most well-known example. Therefore, a better understanding of cavitation behavior is of vital importance for further optimization of next generation fuel injectors.In contrast to the abundance of investigations conducted on the inner flow and cavitation patterns of diesel injectors, corresponding in-depth research on the inner flow of gasoline direct-injection nozzles is still relatively scarce. In this study, the results of an experiment performed on real-size GDI injector nozzles made of acrylic glass are presented. The inner flow of the nozzle is visualized using a high-power pulsed laser, a long-distance microscope and a high- speed camera. The ambiguity of dark areas on the images, which may represent cavitation regions as well as ambient air drawn into the nozzle holes, is resolved by injecting the fuel both into a fuel or gas filled environment. In addition, the influence of backpressure on the transient flow characteristics of the internal flow is investigated. In good agreement with observations made in previous studies, higher backpressure levels decrease the amount of cavitation inside the nozzles. Due to the high temporal and spatial resolution of the experiment, the transient cavitation behavior during the opening, quasi-steady and closing phases of the injector needle motion can be analyzed. For example, it is found that cavitation patterns oscillate with a characteristic frequency that depends on the backpressure. The link between cavitation and air drawn into the nozzle at the beginning of injection is alsorevealed.DOI: http://dx.doi.org/10.4995/ILASS2017.2017.4639


2000 ◽  
Vol 1 (2) ◽  
pp. 147-161 ◽  
Author(s):  
J Reissing ◽  
H Peters ◽  
J. M. Kech ◽  
U Spicher

Gasoline direct injection (GDI) spark ignition engine technology is advancing at a rapid rate. The development and optimization of GDI engines requires new experimental methods and numerical models to analyse the in-cylinder processes. Therefore the objective of this paper is to present numerical and experimental methods to analyse the combustion process in GDI engines. The numerical investigation of a four-stroke three-valve GDI engine was performed with the code KIVA-3V [1]. For the calculation of the turbulent combustion a model for partially premixed combustion, developed and implemented by Kech [4], was used. The results of the numerical investigation are compared to experimental results, obtained using an optical fibre technique in combination with spectroscopic temperature measurements under different engine conditions. This comparison shows good agreement in temporal progression of pressure. Both the numerical simulation and the experimental investigation predicted comparable combustion phenomena.


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