Overview
As the world transitions from fossil fuels to green energy, electricity is the first thing that comes to mind. Manufacturers are leaning towards more fuel economic and zero emission transportation vehicles.
The objective of this team-project was to design a two wheeled electric motorcycle which will be capable of traversing through an urban environment. The key design aspects we focused on was a motorcycle that would carry a maximum of two passengers, equipped with a rechargeable battery powering an electric motor that gives you a day’s worth of drivability. We aimed for EleCycle to be able to withstand various cyclic and impulse forces. Initially, the electric-motorcycle's chassis was designed, followed by transmission design.
The electric-cycle's Design Specifications
Maintain speeds of 60[km/h] with top speed of 70[km/h]
Acceleration around 3.5 [m/s]
Minimum ground clearance of a 1⁄2 foot
Maximum Height of 3.5 feet
Overall weight less than 150kgs
Low center of Gravity
Range greater than 100 kilometers
Carry a maximum of two passengers
Chassis Design
Concept Sketches
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Dually - inspired by a tandem bicycle
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High Rise - inspired by a double decker bus
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Streamliner - inspired by a cafe racer
Each group-member played an essential role in designing the electric-cycle. I carried out the design stress analysis via FEA and Fatigue Failure Analysis to ensure that the final design satisfied the design specifications.
FEA analysis and Fatigue Failure analysis were carried at each step of the chasis design process, as shown below by the images:
Preliminary Chassis Design
Stress Analysis of Preliminary Chassis Design
Strain Analysis of Preliminary Chassis Design
Displacement Analysis of Preliminary Chassis Design
Final Chassis Design - Streamliner
Stress Analysis of Streamliner
Strain Analysis of Streamliner
Deformation Analysis of Streamliner
Streamliner Chassis
The final design consists of the streamliner chassis design with a set of wheels and handlebars using screws and fasteners. Also, the final design has gone through many iterations for it to be a viable option and live up to the daily wear and tear, which ultimately result in various cyclic and impulse forces. The key design aspects the team focused on are to design a motorcycle that would give you a days’ worth of drivability using rechargeable batteries and an electric motor, whilst still being able to carry a maximum of two passengers.
The final design that my team came up isn't road ready but the design process from concept sketches, to solidwork modelling, to stress-strain and fatigue analysis has been a great experience.
Transmission Design
Concept Sketches
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Worm gear reducer and V-belt
The initial transmission design sketch required a worm gear reducer to control the high-speed motor being employed in our final product. The worm gear reducer was connected to the rear wheel via a V-belt. Though this design ensured low cost and maintenance, a chain would last longer than a V-belt.
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Spur gear train and sprocket-chain
The second design sketch required a spur gear train to increase torque from the motor, followed by a sprocket-chain design to drive the rear wheel. This design is more reliable than our initial design, mainly due to chain's longer service life as compared to belt. Moreover, spur-gears give a larger variety and are cheaper as compared to worm-gear drive. It was also noted that the use of spur-gears and chain drive would result in an increase in the weight and space required to hold the system.
A decision matrix that weighed safety as most important, followed by cost,longevity, reliability, maintenance and size was employed to select a tranmission system for the previously designed Streamliner Chassis. The decision matrix can be found in the Transmission Design report. The team decided to go with the second tranmission concept, spur-gear train with sprocket chain. The design process can be found in the Transmission Design report.
Transmission System CAD models
Transmission Sketch
Gear Train
Chain Drive
Shaft
Streamliner Chassis and transmission system