360 detailed design review
Post on 15-Apr-2017
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Powertrain Potatoes
Team Lead: Joseph LerchbackerProject Manager: Calin Solomon
Tyler Bauer, Evan Cassak, Adam Minick, Peter Meyerhofer, Chanisara Netsuwan, Danielle Runzo, Emily Welsh,
Cana Zhang
The TeamJoseph - Team organization and schedule; Weekly reports; Presentations; Cost estimate
Calin - Task breakdown and assignment; Connecting rods; Camshaft; Pushrods; Oil system
Adam - CAD modeling; Cylinders; Combustion chamber; CAD assembly
Cana - Combustion chamber research; Spark plugs; Catalytic converter; Theory of operations
Chani - Thermodynamics math; Gasoline; Intake/Exhaust; Rocker arm
Dani - Standards research; Theory of operations; Combustion chamber; Valves
Emily - Materials; BOM; Off-the-shelf parts; CAD modeling
Evan - Crankshaft; Manufacturing estimate; Reports
Peter - Thermodynamic math; Friction math; Cooling math
Tyler - Piston; Engine block; CAD modeling; CAD assembly
The Challenge
Design Requirements:● At least 2 cylinders● 4-stroke cycle● Displacement 1500-1800 cc● Compression ratio 9:1 to 10:1● Fuel injection, spark ignition, uses standard
gasoline● 5000 rpm continuous service, 800 rpm idle● Powers a 6-speed transmission● Meets safety, fuel efficiency, noise and emissions
standards● Ready for production by 2017
Keep in mind size, weight, cost, fuel efficiency and reliability.
Design Goals:● Meet all design requirements● Mechanical simplicity● Comparable industry size and
weight● Cost of manufacturing < $5000● Fuel economy of > 32 mpg● Lifetime > 20000 miles
Out of Scope:● Transmission design● Designing off-the-shelf parts● Frame mounts● Engine looks
Background: Design a new motorcycle engine for the Spartan Motorcycle Company. Expected sales are 7500 units, 12000 units, and 15000 units in the 1st, 2nd, and 3rd year, respectively.
Dimensions 30"x20"x20" External Temperature < 300F on cylinder external .surface
Weight < 250 lb Surface Temp. of .Combustion Chamber
< 800 F on average
Noise Conn. Agencies Regs. § 14-80-1. For "soft" sites: 78 dB <35 mph; 82 dB >35mph For "hard" sites: 80 dB < 35; 84 dB >35 mph
Operational .Temperature
operate from -40 to 120F
Standard .Gasoline
> 89-octane gasoline Power > 60 hp at 5000 rpm
Emissions 40 CFR 86 subpart F < 12 g/km CO < 0.8 g/km HC + NOx
Vibrations < 2 Hz at 5000 rpm
Fuel Economy > 32 mpg combined Safety ISO 4106-2013
Lifetime 100 million crankshaft cycles Bore/Stroke Ratio 1 < ratio < 1.25
Cost < $5000 (to manufacture) Piston Speed < 15 m/s
The ChallengeDerived Requirements:
The Engine
Which engine type should we build?
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https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcT4awf38oO9z_DrdXKqMrrOhFoIrg
http://pxhst.co/avaxhome/86/c0/0014c086_medium.jpeg
The Engine
Which engine type should we build?
The EngineWe present:
The Tuber Twin
Engine Type Boxer Twin
Displacement per Cylinder 45.5 cu.in. (745.8 cc)
Bore-to-Stroke Ratio 1.24
Compression Ratio 9 : 1
Fuel Economy 36.3 mpg combined (31 city,43 hwy)
Emission Standard Meets EPA 40 CFR Part 63
Max Power 93 hp @ 6000 RPM
Max Torque 87 ft-lb @ 600 RPM
Weight 120 lbs (dry), ~140 lbs (wet)
Envelope 29” x 12.6” x 16.8”
Manufacturing Cost $2857
Tuber Twin: Technical Specs
Tuber Twin: Technical Specs
*** We also confirmed these numbers by running our engine dimensions on an engine simulation software from our resources at the Cleveland Motorcycle Co. and the results were similar.
Tuber Twin: Theory of OperationDesign Advantages:
- smaller envelope- fewer parts- good power/torque balance- low center of gravity- simple cooling system- easily balanced moments
Basic 4-stroke, direct-injection, combustion engine.
http://animagraffs.com/how-a-car-engine-works/
Tuber Twin: Theory of OperationDesign Advantages:
- smaller envelope- fewer parts- good power/torque balance- low center of gravity- simple cooling system- easily balanced moments
Boxer Twin - tandem piston movement
http://bmwmcmag.com/Classic-Boxer-Sprint-4-570x362.jpg
Tuber Twin: Thermal Analysis
28.9% Thermal Efficiency (2500 RPM, full throttle)
222
213
Since less than half throttle is actually required for cruise at 60 rpm, under any common conditions a 90% effective catalytic converter at 10% excess air
will bring emissions within EPA limits.
Emissions
FMEA
http://www.off-road.com/aimagesstandard/232006/332673/1.jpeg.jpg
http://www.bmbikes.co.uk/photos/museum/Broken%Crank.JPG
http://www.surfacezero.com/g503/data/500/PC010638.JPG
Failure Trends & General Solutions
- Design Calculations:
- proper research, - proper math, - double checking, - software simulation
- Oil System:
- proper research, - consult expert
- Manufacturing/Assembly: - planning how to machine and assemble as we design, - consult expert
Components: Crank- and Camshafts
3-Arm Crankshaft for Simplicity and Size
Components: Crank- and Camshafts
Components: Piston and Arm
Largest force experienced is 79kN when combustion takes place.
With a safety factor of 2, our parts were designed to withstand 158kN of force.
Components: Piston and Arm
Important Dimensions
Components: Piston and Arm
Ixx = 419/12*t^4 Iyy = 131/12*t^4
t = 0.12”
Components: Lubrication System
All journal bearings were designed to fit standard size
bushings and the bearing length and film thickness were
calculated according on the forces needed to withstand.
The Tuber Twin is designed for SAE 20W-50 oil.
Materials & ManufacturingComponent Material Manufacturing Method
Engine block Al Alloy 356 Cast + Machining
Cylinder Al Alloy 356 Cast + Machining
Cylinder Head Al Alloy 356 Cast + Machining
Cam- & Crankshaft Steel Alloy 4340 Forged + Machining
Connecting Rod Steel Alloy 4340 Forged
Rocker Arm Steel Alloy 4340 Drop Forged
Piston head Al Alloy 332 CNC machining
Engine Front Cover Nylon 6,6 Composite Injection Molded
Intake manifold Nylon 6,6 Composite Injection Molded
Exhaust manifold Ductile Cast Iron (ASTM A439) Cast
Assemblies and Drawings
Assemblies and Drawings
Assemblies and Drawings
Make/Buy Decisions and BOM
Parts customized for our engine are made; parts standard across
many engines are bought.
Make/Buy Decisions and BOM
Cost of MAKE $1,326.51
Cost of BUY $1,370.85
Cost of LABOR $160
TOTAL COST $2,857.36
# Distinct Parts 59
Total # Parts 161
Purpose of BOM:● Track all parts● Cost tracking● Weight tracking
QA Testing PlansAs part of the manufacturing process, we will be testing 3 randomly selected engines from each manufacturing batch. One for each extreme weather condition (hot/cold), and one in normal conditions. Each engine will be tested according to ISO 4106.
● Prior to testing, all engines will be assembled per ISO 4106 Section 6.3.1● Torque and power, corrected for estimated transmission inefficiencies, will be
measured once temperature, torque, and speed have reached steady state. ● Specific fuel consumption and emissions at each test state
Significant deviations from calculations or past history will trigger investigation or maintenance. Control charts will track result history.
Dimensions 30"x20"x20" 29”x12.6”x16.8” External Temperature
< 300F on cylinder external .surface
213 F
Weight < 250 lb 120 lb Surface Temp. of .Combustion Chamber
< 800 F on average 280 F
Noise Conn. Agencies Regs. § 14-80-1. Tentative Operational .Temperature
operate from -40 to 120F
Satisfied
Standard .Gasoline
> 89-octane gasoline 89-octane gasoline Power > 60 hp at 5000 rpm …...
77 hp @ 5000 rpm(93 hp @ 6000 rpm)
Emissions 40 CFR 86 subpart F < 12 g/km CO < 0.8 g/km HC + NOx
Satisfied Vibrations < 2 Hz at 5000 rpm Tentative
Fuel Economy
> 32 mpg combined 36.3 mpg combined Safety ISO 4106-2012 Satisfied
Lifetime 100 million crankshaft cycles Satisfied Bore/Stroke Ratio
1 < ratio < 1.25 1.24
Cost < $5000 (to manufacture) $2857 Piston Speed < 15 m/s 14 m/s
Design Requirement Satisfied
Questions?
Performance GraphsBHP = Brake HP (after friction)
43 mpg (2500 RPM, 60 mph, full throttle)28.9% efficiency (2500 RPM, full throttle)
Half throttle is the more realistic condition.Design for 10% excess air.
Running Temperature1500 RPM at 25 mph2500 RPM at 60 RPM (cruise RPM)
Linear interpolation between extremes
75 F external air temperature
Applies to any throttle setting¾” circular fins, 21 per cylinder
Idling Time30 mph cruise at 120 F: runs at 250 F
Maximum service temperature of A356 is 340 F
Can idle at 120 F for 25 minutes without a major risk of overheating
Applies to any throttle setting¾” circular fins, 21 per cylinder
Combustion Temperature and Pressure
Gordon-McBride ProgramComputes the chemical equilibria of combustion.
EmissionsHydrocarbons are negligible (less than 10^-4 mole fraction).
Will need a catalytic converter on the exhaust pipe. Normal riding at less than half throttle also helps.
Links to Full DocumentsFMEA LinkBOM LinkCosts LinkTheory of Operation LinkCDR
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