Honda Engine Repackaging 2016
Our goal was to repackage a Honda CRF-150r into a two cylinder electric hybrid.
|Next Gen Engine|
|Duration||Summer 2016 - Fall 2016|
To maintain a competitive advantage in the Formula Hybrid SAE competition, a new exotic and legendary engine design is needed for the University of Idaho race car. The solution is to reverse engineer a Honda CRF-150r one-cylinder engine with computerized micro measuring and laser scanning technology and turn it into a two-cylinder 250cc engine.
The Formula Hybrid team at the University of Idaho is in need of a new engine configuration to remain competitive for future competitions. To incorporate the electric motor and maximize engine displacement, a new engine must be designed that has separate engine cylinders. This will require research of an engine with comparable features and design.
One of the main goals of this project was to reverse engineer the Honda CRF-150R engine, while this process took place we documented any findings we made as well as how we took apart the engine. This project required more than just reverse engineering the engine but also required that we learn to use the metrology equipment and Solid Model the engine using the CAD program Solidworks. The Metrology equipment we used included calipers, CMM, laser scanning technology and scaled photographs.
The second goal of the project was to combine CRF-150r engines together and reduce their displacement to a total displacement of 250 cc. The original CRF-150r is a 150cc, so that meant altering the crankshaft of each engine. We designed a configuration with the engines parallel to each other and with the engines co linear. The configuration of the parallel engines is based of a gear box design from another project relating to a Yamaha engine.
|CMM at University of Idaho Metrology Lab||Laser Scan of the CRF-150R Crankcase|
|CMM||The Coordinate Measurement Machine(CMM) is used to make precision measurements on unusual geometrical objects, we learned how to use the CMM and created a document to assist other students.||We used the CMM to find radii for the curves on the valve cover, center to center distances for the gears and anything else that was not easily measured with calipers.||The CMM was a powerful tool, but we used it more than we needed. If we were to do things differently, would should have focused more on critical dimensions and not getting every surface perfect.|
|3D/Laser Scanner||We worked with Alex Olson to use the hand held laser scanner. It took practice and some ingenuity to use it well. The laser scanner images were exportable to Solidworks. It would create a 3D part using a complex combination of triangles, we would then have to manually clean up the images in Solidworks. The software Geomagic can be used to make the scanned images better.||We used the laser scanner on our most complex of parts. This included the crankcase, cylinder head and camshaft carrier.||We were impressed with the laser scanner; however, it is not useful for modeling the entire engine. The files it creates are very large and difficult to manipulate. It is best to use the laser scanner for only the hardest parts. The laser scanner does not do away with hard work.|
We had multiple methods for drawing complex parts in Solidworks.
- (1) We used the metrology equipment to find shape sizes and scan the most difficult parts.
- (2) We used scans and photographs to trace in Solidworks. Solidworks also has an auto trace function that is useful. We used this for doing the logo on the valve cover.
- (3) To draw the shift drum we were able to roll its design on piece of paper and then turn that into a 3d model after tracing it.
|Solidworks Render||Example Photograph for CAD Modeling||Exploded View(Clutch)|
|Gearbox Exploded View||Timing Chain||Connecting Rod|
|Accuracy||Create an accurate representation of the CRF-150R Honda engine using Solidworks.||The parts were modeled well enough to construct a complete assembly of the engine that could be animated.||We created many parts that may not be necessary for the basic modeling of the new engine configuration.|
|Drawing Package||Create a way to make the parts easily accessible for future teams.||We organized all of the parts by Honda part numbers in the shared folder, available for easy future use.||Some additional parts that are not original equipment on the engine are in other folders.|
|Animations||Make an animation of the motor which will show the exploded views and how the motor operates.||We created basic animations of components of the engine, such as the cylinder head and short block.||There were issues getting the timing chain to function correctly with the whole engine "running" as it would crash Solidworks.|
The 150cc CRF-150r needs to be modified to a 125cc and fuel injected. We investigated building air fuel ratio (AFR) maps and optimizing spark timing. These images show theoretical power curves and brake specific fuel consumption (BSFC) for a 125 cc version of our engine. By reducing the engine size, a power loss of about 4 hp should be expected.
Following is the dimensions required to make our 150cc into a 125cc, these dimensions were used in the Matlab model: L = (36.5/1000) Stroke of Engine [m], B = (66/1000) Bore of Engine [m], l = (75.4/1000) Length of Engine Connecting Rod [m], C_r = 11.8 Compression Ratio, IVC = 0 Time [degrees] when Intake Valve Closes, EVO = 314 Time [degrees] when Exhaust Valve Opens
|BSFC - Theoretical||Power and Torque Curves - Theoretical|
After modeling was completed the next task was to reconfigure the motor for potential formula hybrid competitions. This configuration places the crankshafts parallel to each other. The power is then transmitted from each crankshaft and the electric motor to a ring gear on the flywheel. From there the power goes out to the wheels thru a differential. Some issues with this include creating enough room for an air intake and considering if a balance shaft is necessary.
We also considered a configuration where the crankshafts would be coaxial. In this case we would build a new crankshaft that served both pistons. In between the engines along the crankshaft there would be room for an electric motor.
|Engine Configuration (Parallel)||Engine Configuration (Parallel) - Gearbox||Engine Configuration (Inline)|
Copies of all resources are located on the shared drive: S:\Engineering\SeniorDesign\- Senior Design\2016 Summer & Fall\DoublExotic\Research
We considered the effects of having to use an air restricter:
- Singhal, Anshul, and Mallika Parveen. "Air Flow Optimization via a Venturi Type Air Restrictor." Proceedings of the World Congress on Engineering 2013. Web
Information on basic engine principles:
- Soruşbay, Cem. "COMBUSTION in SI ENGINES - Internal Combustion Engines – MAK 493E." Istanbul Technical University. Web.
Information for changing the displacement of our engine and more:
- Burgess, Dave. "Gasket Thickness Decisions." Garlock Sealing Technologies. 2003. Letter.
- Becker, Stephan, Peter Farnum, Jacob Morissette, and Dwight Whitney. "University of Maine FSAE Engine Team - Preliminary Intake Design."
- Pitsch, Heinz. "Laminar Premixed Flames: Kinematics and Burning Velocity." CEFRC Combustion Summer School 2014. Institut fur Technische Verbrennung.
We were concerned that the valve seats on our engine were worn, we consulted this resource:
- "Valve Face Wear or Guttering and Valve Head Tuliping/Cupping." Service Engine Bulletin. Australia Engine Technical SB018.
|Freddy Mark||Mechanical Engineering|
Freddy is a senior in Mechanical Engineering. Born and raised in Boise, ID and is a transfer student from College of Southern Idaho. Favorite activities include boating, riding, and running. The most beautiful thing we can experience is the mysterious. It is the source of all true art and science.
|Alex Wright||Mechanical Engineering & Applied Physics|
Alex is a senior in Mechanical Engineering and Applied Physics. Born and raised in Boise, Idaho, I love working on cars and engines. I am also a member of the University of Idaho's Clean Snowmobile Team.
|Alexander Fraser||Mechanical Engineering|
Alex is a senior in Mechanical Engineering. Originally from Honolulu, Hawaii moved to Idaho to pursue a degree in Mechanical Engineering. I'm always curious to learn new things and explore what I haven't seen or experienced.
|Alexandr Martonick||Mechanical Engineering & Foreign Language|
Alex is a senior in Mechanical Engineering. Between 2007 and 2011 Alex studied German language at Washington State University. In 2010 He lived in Munich Germany and worked in marketing and studied at the Ludwig Maximillian’s Universität. In 2011 Alex began studying engineering at University of Idaho. His hobbies include racing and modifying BMWs for performance with his friends and cooking exceptional food.
Our Solidworks files are located on the UofI shared drive: S:\Engineering\SeniorDesign\- Senior Design\2016 Summer & Fall\DoublExotic\CRF150R_HONDA\Modeling Package
The files are organized according to their Honda part numbers. Anyone can find a file by knowing the Honda part number or referencing the repair manual to obtain a part number.