EVO 3

ELECTRONICS

Our tasks include programming the control unit of our engine, purchasing, installing and calibrating the necessary sensors, and manufacturing the cable harness that connects them. This also includes the necessary preparations for bench and car tests, and part of the conduct of the tests.

For our EVO1 and EVO2 engines, we used the MS4 engine controller and sensors provided by Bosch Motorsport, we built a unique cable harness, which also includes a wireless telemetry system, which can be used to remotely read and record 15 different parameters of our engine.

For our EVO3 engine, we use a KTM engine controller and electronics in the name of cost-effectiveness and simplicity, for which we only built an additional cable harness. In addition to all this, we are at the disposal of the other departments, as long as the electronics required for their development are also available, such as electro-pneumatic transmission, electro-hydraulic clutch actuation, or intake pipe length actuation. During all of this, we often use microcontrollers, with which we can improve our C programming skills.

Our upcoming brake bench would not be able to operate without electronics, so we will do our part here as well. Our team members can familiarize themselves with the control of electrical machines, which is done with a frequency converter. This and the house technology are controlled via a CompactDAQ system provided by NI Hungary Kft., with a LabVIEW program running on a PC.

During our brake pad measurements, it is important to measure the various parameters of our engine (temperatures, pressures, volume flows, strains…) and record these results. We also implement these with a CompactDAQ measurement data collection system.

COOLING-LUBRICATION

In the cooling-lubrication department, the task of the team members is to build the engine’s oil and water circuit. We have to ensure the optimal temperature and lubrication of the components, and we also strive to keep the weight of the system as small as possible. For the operation of the engine, it is essential to supply the right amount of oil and water to the system, just like the intake and circulation.

In cooperation with other departments, the planning, placement and production of our components is also part of our work. The individual parts (e.g. oil pump) must fit perfectly, not only in themselves, but also in terms of the entire system. It is also our task to ensure the connections (holes, pipes) between the various components. Most of the design is realized with the Creo 2.0 program, however, we try to optimize certain parts with CFD simulation.

In our system, we currently use a factory aluminum water pump with a custom rotor to withstand the loads placed on it. Our oil pump is a trochoid type of our own design, with a delivery capacity of 120 liters/1000 pump revolutions/hour. The oil tank can store 800 ml of oil, with a built-in dripper and crankcase gas drain. For the EVO 3 engine, we chose the dry sump solution, with suction on each side, so that despite the lateral acceleration of the engine during the race, the oil circulation is problem-free.

CYLINDERHEAD

Our current cylinder head is based on a serial KTM cylinder head. This SOHC-controlled, four-valve series cylinder head is an excellent starting point for its weight, price, and competitiveness. However, to make it even more competitive, we have made several improvements to it.

First of all, we further developed the control, thus creating a unique adjustable camshaft with unique cam profiles. In addition, a unique enhancement device was also made for the most accurate and simple enhancement. This adjustable camshaft, however, will only be used for bench tests. For this reason, our ongoing project is the design of a unique camshaft with the above-mentioned in-house camshaft cam profiles.

In addition, in order to further develop the valve control, we are also planning a sliding valve rocker instead of the standard roller valve rocker, with which we can further optimize the valve control, thereby the entire charge exchange. In racing, it is essential to have an engine as light as possible, so we must gain as much mass as possible not only on the valve control elements, but also on the casting itself. Therefore, among our current projects is the simplification of the cylinder head casting. In addition, it is also important to reduce mechanical losses, so we also deal with the coating of existing parts in the department.

We use the Creo 2.0 program for modeling, the AVL ExciteTiming Drive and finite element simulation programs for valve control simulation. None of our projects would have been possible without the aforementioned programs.

TEST DEPARTMENT

It is one of the most exciting and complex departments of our team. Our tasks include handling, checking and assembling the parts of our engines. The people working in the department must know the smallest details of our engines, so they must also participate in the design phase.

Most of our tasks consist of running our engines, which take place according to predetermined plans. During the tests, we first examine our motors without load, from a mechanical point of view, then the load tests follow.

In addition to engine assembly, we also deal with car assembly and engine installation, as our team previously bought an older Formula Student car, so the tests could start thanks to this. At our university, there is a stationary roller brake bench, with the help of which we can find out the force of our engine on the ground

In the near future, we will be able to test our engine on our own motorcycle brake bench, which is also unique in Formula Student. This is our own engine brake bench specially developed for testing our single-cylinder engine.

It is important that we feed back on the construction with our experiences and results arising during the tests, so that our next engine can be made in an improved version.

CRANK MECHANISM

The heart of the crank mechanism is the crankshaft. The crankshaft of our third-generation engine is a completely uniquely designed part, the so-called ‘full ham’ design. Unlike our previous engines and many series single-cylinder engines, we abandoned the flywheel and tried to integrate the flywheel mass into the crankshaft. The main reason for this was to make our motorcycle as compact, simple and light as possible. At the same time, by integrating the swing mass into the crankshaft, we brought the load closer to the rolling bearings, eliminated the stress on the flywheel shaft end, and of course the shaft end itself was shortened.

The crank mechanism also includes the encoder disc on the crankshaft, the control sprocket, the starter motor gear and the clutch drive gear. We use factory pistons and connecting rods, but we are constantly working on a custom-developed connecting rod as well. The main goal is to reduce the mass of the series connecting rod with a completely unique geometry. At the moment, we are also working on the integration of the encoder disc into the crankshaft ham, so after the flywheel, this would be the second component that would be completely detached from the shaft end and placed in the crankshaft ham.

Modeling is done using Creo, and simulation is done with several programs. In the department, we use various finite element modeling programs, with which we can determine the stresses of the components. We use two types of programs from the AVL program family. With the AVL Excite Designer, we can determine various torsional stresses, the angular rotation between the two ends of the crankshaft, the angular inequality, the critical speed, etc. And from the AVL Excite Power Unit, we can extract the displacement and rotation of the main pins and the crank pin.

CRANKCASE

What is a crankcase and what is it good for? The crankcase is the part that includes the different parts of the engine, it is the ‘body’ of the engine. This also means that this part is the most closely related to the operation of the other parts, because the ‘body’ has something to do with almost every part. What can be influenced with it? The arrangement of the engine components, which greatly influences the subsequent weight distribution, center of mass, and these greatly influence the performance of a racing car on the track.

At first glance, a crankcase is not a complicated part. If we can get a glimpse into the making of a crankcase, we will already see it differently. This is the part that has to absorb 10-30 kN (1-3 ‘ton’) loads with the smallest possible weight on relatively small surfaces, due to which huge mechanical stress just ‘zigzags’ in it in almost all directions. Currently, there is an EVO4 crankcase under design, which, in terms of layout, has changed a lot since EVO3, and it is constantly developing and evolving.

For modeling, we use the Creo Parametric program, and in addition to modeling, finite element simulations are absolutely essential, which, in addition to Creo’s integrated simulation module, are also performed in several other finite element programs, since without finite element simulations it would not be possible to determine with certainty where the weak points are from each geometry. points, where there are excessively strong points, where the deformation is excessively large, approx. what is life expectancy In competitive sports, this is especially important, because every gram of weight reduction gained is an advantage with the same strength.

In these months, we started dealing with topology optimization (Tosca, Abaqus Atom), which is a revolutionary new design procedure, thanks to which we are able to ‘mill out’ the lightest available geometry from the model.

Knowledge of these programs is essential in the department, as well as the enthusiasm of the department members for what they do, be it modeling or simulation.

GEAR

Our EVO3 engine has an integrated gearbox, thanks to which the use of space and layout is more optimal. Since the smallest possible weight plays an extremely important role in competitive sports, thanks to this design we gained a lot in terms of total weight. Our gearbox is based on a commercially available gearbox. From the original 6-speed gearbox, we left out the fifth and sixth gears, because according to experience, four gears are perfectly enough to complete the Formula Student races. This way we were able to win another crowd. Due to the omission of the mentioned stages, we had the opportunity to design a unique coupling shaft (spindle shaft), which was made of steel by cutting. For shifting, we use an individually designed fully mechanical actuation, which switches the gears using a pull-push cable.

Among our current projects is the further development of actuation for our EVO4 engine. Among others, stepper motor and pneumatic solutions were considered as possibilities. In addition, the development of an anti-hopping clutch is ongoing, the advantage of which is that no special attention needs to be paid to avoid blocking the rear wheels during the braking phase. In order to further reduce weight, we are continuing the design of the lighter coupling shaft. Furthermore, the redesign of the transmission axles is underway, as their lightening can be a major advantage.

In our department, we most often use the PTC Creo 2.0 program for planning, and we also use finite element simulation.

AIRSUPPLY

The air supply department also deals with the intake system, the exhaust system and the fuel supply system. For the time being, we are dealing with filling the intake system, and with this we improve the filling exchange, but there are also plans to develop a turbocharged engine. Formula Student rules must be taken into account for the designs, according to which a 19 mm reducer must be used for ethanol and a 20 mm reducer for gasoline. Furthermore, from the point of view of engine performance, the optimal pipe lengths must also be taken into account, as well as flow losses, including surface roughness and the radius of curvature of the pipe. All these little things affect the performance of the engine.

The lengths of the pipe and the volume of the airbox are obtained by 1D flow simulation using AVL Boost. In the case of the exhaust system, we also obtain the pipe length with a 1D flow simulation. The flow is also of great importance here, although the combustion product has already left the cylinder, with the help of pressure waves, the engine’s performance can be further increased. Due to the limited dimensions of the car, it is a big challenge to place the intake and exhaust system with the appropriate parameters.

Among the completed airbox geometries, we select the most suitable one with a 3D flow simulation, if necessary, we refine it here, with rounding and minimal geometry changes.

We also work with CREO Parametric 2.0 for the intake and exhaust system and model all parts in it.

The fuel system runs from the pipes starting from the tank to the injector. We choose a fuel pump, pressure regulator, fuel filter, etc. for the correct injector.

All parts are made using the most modern and state-of-the-art technology, starting from 3D design to the lamination of the intake pipe.