One of the ICE:s mounted on the engine plate
Jonas has spent almost all of his time in the project with the ICE. ICE is an abbreviation for Internal Combustion Engine – the machine that transforms chemical energy in the fluid (in this case ethanol) into mechanical energy. We use the term ICE to distinguish it from the electrical motor – which transforms electrical energy into mechanical energy. Jonas is very handy with ICE:s in general and doing his Master thesis in Energy engineering in the scope of the project. This means that apart from the rest of Team Baldos he doesn’t do any other courses parallel to the project – which can be seen in his time-log.
The ICE:s we use are virtually the same for both vehicles and are in fact modified model-plane engines; Fuji Imvac BF-25EI. They’re quite small (25 cc) and weigh around a kilo a piece, but are still fully functioning four-stroke gasoline engines. KG Knutsson has supplied us with spark plugs suitable for such tiny mechanisms.
Since Jonas knows a lot of ways to modify engines, the issue has always been to decide which improvements to choose from in the long list he’s come up with. These are examples of what he’s accomplished so far:
- A new cooling system based on automatic circulation of water. Model-plane engines are normally cooled by the airflow from the propeller, but since Baldos II doesn’t have one of those, insufficient cooling is what caused the breakdown during last year’s Shell EM.
Jonas inspecting the ICE cooling system
- Conversion from carburetor to fuel injection. With fuel injection it’s possible to calibrate the fuel/air mix with the lambda (oxygen) sensor to get most out of the fuel injected.
-Higher compression ratio by extending the connecting rod. This is required for using ethanol, but it also increases efficiency.
- Piston modifications for improved gas flow behavior, which means less fuel waste.
- Intake manifold – an intuitive way of optimizing the airflow into the engine by creating a standing wave of air by the intake.
- Altering of the valve-opening cycle for more exact opening times.
- There’s also been a discussion about a heavily efficient new way of handling engine cooling, but because of lack of time, its relative complexity, and because the engines might cool down too quickly, we might save this one for next year.
In the process of doing these modifications Jonas has had great help from Metallic polymers supplied from Belzona.
Fredrik and Jonas during a dynamometer test run
Unfortunately Jonas has also been quite occupied with the dynamometer. The first plan was to have it finished already before Christmas, but mechanical issues made it reach over new years. Then, while testing with a motor sponsored from Honda motors, there were some electrical systems failures. After that we encountered vibration problems; probably because of dysfunctional connectors between the dynamometer and the engine.
Poor Jonas spent a lot of hours trying to fix it, assisted by Janne. Luckily, it all came together after exchanging the previous connectors with a Polhem knot (a Universal joint), and right now we are using the dynamometer to test the ignition module, ECU and compression ratio, and of course to optimize the engine by searching for the most efficient engine rpm.
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