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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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

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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

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