How to Avoid Engine Knocking? Researches from the Warsaw University of Technology Will Find Out

The quality of fuel is very important for proper combustion. Knocking combustion, also known as “knock”, is the phenomenon of incorrect combustion of fuels in spark-ignition piston engines. Researchers from the Warsaw University of Technology are trying to find a solution to this problem.

Exchange of Knowledge and Experience

Young researchers from the Faculty of Power and Aeronautical Engineering at the Warsaw University of Technology want to tackle the issue of knocking combustion in high-power gas engines. On behalf of the Warsaw University of Technology, Łukasz Jan Kapusta, PhD (Eng.) from the Division of Aircraft Engines acts as the leader of the project named “Preventing Knocking Combustion and Increasing Reliability and Performance of High-Power Gas Engines”. The project is funded by the Horizon 2020 programme, commenced in December 2015, and its execution is planned to take place over four years.

Horizon 2020 is the largest scientific research and innovation funding programme in history of the European Union. Its budget for 2014-2020 is nearly EUR 80 billion. The main purpose of Horizon is to create a coherent system for financing innovation: from the scientific idea, through research, to the implementation of new solutions, products, or technologies.

It will enable nine young scientists from the Faculty of Power and Aeronautical Engineering to leave for internship in Wärtsilä Finland Oy and AVL List GmbH in Austria. Wärtsilä is the largest manufacturer of stationary and marine engines in the world, and gas engines are an important part of its operations. On the other hand, AVL is the leading manufacturer of research devices for engine laboratories, and the supplier of advanced numerical software simulating combustion processes in engines AVL FIRETM. In turn, employees of both companies will visit WUT’s laboratories.

What Is Knocking Combustion?

Young researchers from WUT will tackle the issue of knocking combustion. This term is derived from acoustic phenomenon resulting from strong pressure oscillations in the combustion chamber, which occurs during this undesirable process. The phenomenon of knocking combustion does not only occur in vehicle engines, but also in stationary high-power gas engines used to produce electricity.

High pressure oscillations occurring during knocking combustion also result in high stress for the crankshaft. Long-term occurrence of this phenomenon leads to the complete destruction of an engine.

It is hard to find a single solution for eliminating knocking combustion, because it has no single cause. It is influenced by: the type of fuel, engine performance characteristics, and geometric parameters of the engine’s combustion chamber. From the user’s point of view, the basic solution to this problem is using appropriate fuel for a given type of engine, in accordance with the manufacturer’s instructions.

However, the knock phenomenon is a true challenge at the engine construction phase. “On one hand, we would like to use waste or alternative fuels (with high hydrogen contents), on the other hand, we would prefer to increase engine performance”, says dr Łukasz Jan Kapusta. “These requirements are mutually exclusive, so, in order to reconcile them, the largest amount of work must be done during the design phase”.

We Create New Solutions

Knocking combustion cannot be completely eliminated, but the researchers want to minimize its risk. Experimental research will be conducted as a part of the project – checking different fuel mixtures, with plans for designing new engines and developing knocking ignition and combustion models in numerical methods.

All participants of the project have a common main goal: “To increase the efficiency of gas engine combustion, and to avoid the phenomenon of knocking combustion”, Dr. Kapusta explains.

The scientists are also interested in the following aspects: engine start failures and related risk of explosion in the exhaust system, as well as in determining the likelihood of knocking combustion for individual fuels. The final effect of the project will be, above all, the exchange of experiences and closer cooperation with industrial partners. Furthermore, the project will also have a large influence on both creating new ignition models, as well as on structures and technical solutions used in future engines.

Engineer in Business

The Horizon 2020 programme, by principle, assumes intersectoral cooperation. Although the best specialists work in the automotive industry, assistance of scientists allows them to look at given issues from another perspective.

“The industry lacks to time for deep theoretical analysis and strictly scientific work and, sometimes, in order to go deeper, we need to learn more about nuances of researched phenomena”, Dr. Kapusta explains. “Here’s where we help”.

Thanks to such exchange, young researchers from the Warsaw University of Technology may in turn learn how to apply the knowledge they obtained at the university in practice – how to translate it to actual business solutions.

Monika Bukowska

Office for Promotion and Information