The crankhous, cylinder and cylinder head have not changed compared to the last generation engine, after we succeded to make a competitive base engine. To the season of 2017 the thermodynamic and electronic developments came into view.
Among the deficient of the EVO4 engine was included the destitution of the alternator, which was eliminated with the appropriate modifications of the crank mechanism and the cover. That one decision has been taken before the start of the design the EVO5 engine’s, that the team doesn’t design a completely new conception, but the 4th generation engine will be redesign. It played part of the selection the suitable, on the market available alternator’s, because therefore the number of the potential alternator construction were reduced. It was arisen various ideas with different alternators, one of which the best solution was the three-phase permanent magnet alternator of the Kawasaki ZX10R motorbike, which was manufactured from 2004 to 2005. According to the basic concept had to place a flywheel on the crankshaft, which have magnets on the inside surface. The winding of the alternator was fixed in the cover with screw connection. This expectations influenced the design of the fifth generation engine significantly. The placement of the profile the crankshaft position sensor’s was have been to change. In this season was used only the profile of Bosch position sensor with less modifications and the profile of the KTM position sensor was left. The biggest challenge was during the design of the crank mechanism the narrow space and the appropriate fixing of the flywheel. A flywheel holder was designed according to purpose, which transmit the moment through fitted bolts toward the flywheel. A cone connection carries the moment transmission between the holder and the crank shaft. The fixation is executed with a grooved nut and a washer. The mass balance of the crankshaft was designed so, that the crank mechanism is useable for two different connecting rods by the help of tungsten rods. Therefore the crank mechanism is useable with the own designed titan connecting rod and with the series produced KTM connecting rod too.
The Formula Student rules specifies that a 20 mm restrictor must be installed into the intake system betweenthe throttle valve and the engine, where all the intake air must go through. The restrictor’s function to creat a pressure drop in the intake system what considerably spoil the engine’s load exchange process. The purpose of the intake systam planned for the EVO5 was to minimalize that effect as well as to find the optimal formation between the available performance and the optimal gas reaction level.
The structure of the intake system
During the planning process more software was available thanks to the SZEngine sponsor agreements. Such as the parametric modul of PTC Creo 3.0, in which the intake system has been modelled and placed in the car virtually. In favor of the efficient and fast planning the effects of the changes has to be known to the whole system, so simulation runs are indispensable. The engine’s load exchange process and the effects of the new intake system to the load exchange has been examined by one dimension simulation. For this task the Turbocharge module of the AVL software has been used. In the end for the more detailed analysis of the flow, it has been examined in a three dimension hydrodynamic software. For these tests the CCM+ modul of the STAR software was available. The part has been examined by further CFD simulations to find any possible detachments.
To specify the final parameters the team used their own created engine testbench for measurements. The purpose of these measurements to confirm the TURBOCHARGE simulation results in real circumstances. The tests were directed to choose the length of the intake pipe and to specify the volume of the airbox.
The intake system for the race and for the testbench was produced by different technologies. For the testbench, the Varinex 3D printed intake system has been made. But to the races, laminated system has been made with the Arrabona Racing Team, which has a really big carrying capacity compared to its mass. In the picture that intake system can be seen what is installed in the ART04 car.
Our EVO5 engine has gone through great changes compared to the EVO4, most of all electronically. We replaced the DTA motor controller what we used in the last season, instead a Bosch MS4 was used. This motor controller can perform much more complex tasks, and its important for the motor fine tuning. Hopefully we can optimize our engines fuel consumption and power. Furthermore this controller is much easier than the previous one, and the electricity consumption is much less. The sensor system has been changed, the new ones were fitted to the new motor controller, and the target was using the easiest sensors. There was another big change on the engine, one generator was placed on it, which serves the racing cars energy needs, and charges the battery. The generators maximum performance is 500W, what fully satisfies this racing cars needs.