The research project titled "Conceptual study of an advanced ethanol engine" seeks to evaluate the possibilities of applying advanced technologies associated with the specific characteristics of ethanol as fuel.
Technologies not yet tested on dedicated ethanol engines:
- Variable compression ratio and displacement
- Variable valve timing control
- Turbocharged with exhaust gas recirculation (EGR)
- Direct fuel injection - premix strategy
- Late direct injection - stratified loading strategy
- Injection of water for emission control and detonation
- Massive use of sensors, actuators and control strategies
All of these technological options are being evaluated isolate or combined to increase engine efficiency, taking advantage of the high octane rating of ethanol, its higher burning rate and high latent heat of vaporization.
Detailed aspects of the mixture formation (spray) phenomena and the combustion process of ethanol under direct injection conditions in the chamber are a fundamental part of the project and should aid in the definition of injection systems as well as in the control strategies to be adopted.
To address the multiple facets of the research project it is necessary to coordinate different skills from different research groups linked to institutions involved this Project, to generate the desired synergy:
- Develop basic phenomenological studies and knowledge on details of the process of ethanol-air mixture formation through sprays. This comprises CFD techniques for modeling and experimental validation of spray formation, droplet size distribution, fuel evaporation rates, jet penetration, wall impingement, etc.
- Studies on the fundamental characteristics of combustion of hydrous ethanol, including determination of flame speed, flammability limits at high pressure and knocking limits.
- Thermodynamic modeling of internal processes in aspirated or supercharged piston engines: intake, compression, combustion, expansion and exhaust. Simulation performance and parametric analysis of engine operating variables, in order to exploit its trends and guide the choice of experimental tests to be performed.
- Use of test benches for engines, be it to identify areas or processes that require more fundamental studies, be it to the experimental evaluation of the proposed and performed changes.
- Evaluation of kinematics, dynamics and stresses on parts and engine components under the new conditions of solicitation.
- Mechanical designs of new systems or modified devices that reduce friction, allow for variable compression rates, or in some other way contribute to an improved performance and reduced consumption of the engine.
The involved institutions have peculiarities which can complement each other. The Maua Institute of Technology has several test benches for engines and great tradition in providing services to automakers. Such infrastructure will be the basis for tests on modified engines. Both the principal researchers of the Laboratory of Combustion, Propulsion and Energy (LCPE/ITA) and the Laboratory of Environmental and Thermal Engineering - (LETE/USP) work in the study of formation of sprays and combustion fundamentals, and already have an established scientific collaboration, through the use of shared research equipment. The three principal researchers at UNICAMP, working in complementary areas (thermodynamic modeling of engines, engine dynamic analysis, and design of mechanical parts and components) also have an ongoing collaboration.
Activities of theoretical nature, thermodynamic or CFD simulations and experimental engine tests complement each other:
- Experimental motor tests indicate areas in which basic phenomenology research should be deepened and can be used to validate the thermodynamic simulation of the engine or processes.
- Research in basic phenomenology (experimental optical setups and CFD simulation) provides the basis for the development of more robust models and helps to understand experimental results.
- Engine performance simulation models are useful to indicate the most promising modifications to the base engine, as well as to design experimental engine testing, reducing testing time and prototyping costs.