Single cylinder engine design and optimization

ESTECO Academy has partnered with Aprilia Racing and Gamma Technologies to sponsor the design and optimization of a single-cylinder, four-stroke, 250cc engine. The aim of this project is to utilize modeFRONTIER and GT-Suite in numerically analyzing, simulating, and testing to create the ideal race engine.

Background
Grand Prix motorcycle racing is the premier championship of motorcycle road racing, which is divided into three classes: Moto3, Moto2 and MotoGP. Moto3 replaced the 125cc class in 2012. Moto3 runs 250cc single-cylinder engines as opposed to the 125cc engines used previously. Moto GP has been the testbed for many different new engine technologies including finger follower valvetrains, and air valve-springs

Deliverables
The deliverables for the competition include an optimized airbox volume, intake runner, exhaust runner, exhaust pipe length, throttle valve diameter, and valvetrain timing.

Specifications
Displacement: 250cc Cylinder bore = 81 mm  Stroke = 48.5 mm Rev limit 17,500 Conrod length L = 105 mm Inlet Valve Diameter <=34.5 mm (2x) Exhaust Valve Diameter <= 27 mm (2x)  RPM max 17500 1/min Compression Ratio<= 15.8 (compression rate)</li> Valve Cams timing fixed - NOT variable</li> Natural aspiration</li>

Combustion Program (early design development)
We have been using the combustion program written by........... to start early design analysis for the specifications that we were given to us by ESTECO academy. We started by simply inputting our given conditions and running the program, to begin our design we were only curious about the amount of peak torque expected, variable: T_indicated. Without optimization our expected torque is shown below:

The first table shows the effect of a changing burn duration: (crank angle held constant: 170 degrees)

The second table shows the effect of a changing angle of the crank shaft at the start of combustion: (Burn duration held constant: 35 Degrees)

Further development
The combustion code was modified to resemble a crude optimization program, the program will now take one variable and calculate the max torque over a range of that variable. Seen below are two examples of this code.

Implementation of Dr. Odom's Track Program
The use of Dr. Odom's Track program will be to help us choose what engine prameters that we would like to use from our optimization. There were several changed that needed to me made in order to achive this goal.

The first change: The first change was to change the hypothetical track to mirror a track used in moto3 races. The track that we choose was Austrian Grand Pix, seen below. The Austrian Grand Pix has 7 major turns and a lap length of 2.688 miles. While the FinalFormula test track, seen below, has major turns and has a lap length of 2.28 miles.

The second change: The second change was to include fuel consumed by the engine during one lap. To do this we added a a cubic interpolation table with rpm and fuel consumed (lbs/s). We then had TkSolver solve for fuel consumed every 10th of a second using the engine rpm mapped throughout the race course, "fuel_consumed=fuel(engine_rpm)*.1". In this equation fuel is the cubic interpolation table, engine_rpm is the engine rpm mapped during the course, and every number pulled for fuel consumed was multiplied by .1 sec to create a list of fuel used in lbs. The sum of that list is the total fuel consumed. Seen blow in the table is a graph of fuel used(lbs) vs. time(sec).

Overview
One of our initial goals was to integrate modeFrontier with Matlab, Our reason for this was to use the Combustion program to obtain the optimal values for torque and horsepower. These values allow us to estimate the maximum forces that our connecting rod will experience.

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