2 day Visit to VTD, Propulsion Division to give a seminar about diesel injection and combustion, and have collaborative discussions with the Engines Research Team within the Vehicle Technology Directo
Abstract
Engine developers are continuously pushing to improve fuel consumption and reduce exhaust emissions. To this end, research has focused on improving the overall of the combustion engines, in which the diesel direct injection system plays a key role. As a result, a new injector technology known as direct-acting piezoelectric injectors, was recently introduced, as they provide direct control of the needle lift, and thus rate of injection. Moreover, recent findings proved that there is direct link between needle lift and liquid length, adding an extra control variable for engine developers. In this research, results of liquid and vapour penetration are presented for a prototype direct-acting injector at partial needle lift. The main contribution and objective of this work is to provide an experimental analysis of spray penetration, with its corresponding rate of injection at partial needle lift. Spray visualization and rate of injection measurements were carried out at CMTMotores Termicos, the first in a novel high pressure and temperature vessel with continuous flow capable of reaching 1100 K and 150 bar, and the second with a standard injection rate discharge curve indicator based on the Bosch method. The needle lift measurements were previously measured at the Advanced Photon Source at Argonne National Laboratory by means of x-rays. Regarding the results, response of the needle lift for different input voltage of the piezo stack is strongly dependent on the injection pressure. This also affects spray penetration, as results highlight a direct link between needle lift, rate of injection and both liquid and vapour phase penetration. Lower input voltage for the piezo stack resulted in smaller steady needle lift, thus lower stabilized rate of injection and vapour phase penetration. Moreover, and as observed in previous studies, as needle lift decreased, stabilized liquid length also decreased. Additionally, for a given injection and bock pressure, a higher input voltage in the piezo stack produced an initial faster needle response, that resulted in a steeper penetration curve. This proves that, for a direct-acting injector, the beginning of the injection event is largely controlled by the needle lift and not injection pressure. Results presented in this research are valuable for future model validation and a better understanding of the direct-acting injectors.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Oct 06, 2018
- Source ID
- W911NF1710122
Entities
People
- Raul Payri
Organizations
- Army Contracting Command
- Technical University of Valencia
- United States Army