Heads Under PressureHeads Under Pressure

Snowmobile Head DesignSnowmobile Head Design

Team Members: Peter Britanyak, Team Members: Peter Britanyak, Nick Harker, and Chris TockeyNick Harker, and Chris Tockey

DeliverablesDeliverables

Head re-designed to accept pressure Head re-designed to accept pressure sensors for in-cylinder pressure datasensors for in-cylinder pressure data

Research on whether casting the head is Research on whether casting the head is feasible and cost effectivefeasible and cost effective

SpecificationsSpecifications

Pressure sensor to acquire in cylinder pressure Pressure sensor to acquire in cylinder pressure data data

Starting with the design used on the Evinrude outboard motor Starting with the design used on the Evinrude outboard motor Not responsible for data acquisitionNot responsible for data acquisition

Sparkplug Sparkplug Shorter electrode (NGK) Shorter electrode (NGK) 30º sparkplug angle from deck surface 30º sparkplug angle from deck surface Maintain current locationMaintain current location

Injectors Injectors Design injector seating as per email drawings Design injector seating as per email drawings 9º injector spray angle towards intake side 9º injector spray angle towards intake side Near nozzle geometry as per email drawingsNear nozzle geometry as per email drawings

Combustion Chamber Combustion Chamber No dome offset No dome offset Squish area same as turbo head 34% Squish area same as turbo head 34% Dome height approx. 1 inch as necessary for compression ratio Dome height approx. 1 inch as necessary for compression ratio Dome angle needs to be determined for the correct compression ratio Dome angle needs to be determined for the correct compression ratio Compression ratio of 6.5:1 Compression ratio of 6.5:1 Dome radius .75 inches Dome radius .75 inches Cone to plug distance is -.08 inches Cone to plug distance is -.08 inches Squish velocity of 15-20 m/s Squish velocity of 15-20 m/s Squish diameter of 1.95 inches Squish diameter of 1.95 inches Squish radius from cone to squish .25 inches (double turbo head) Squish radius from cone to squish .25 inches (double turbo head)

ManufacturingManufacturing– Research casting as a method to manufacture Research casting as a method to manufacture

the headthe headReport on viability and costReport on viability and cost

Obtain Head bolts long enough to prevent Obtain Head bolts long enough to prevent stripping and uphold aesthetics of motorstripping and uphold aesthetics of motor

Pressure Sensors Pressure Sensors Contacted Kistler about part # 6052CContacted Kistler about part # 6052C

Cost: $2500 eachCost: $2500 each Not part of our budget (from Karen)Not part of our budget (from Karen) There are detailed drawings available so There are detailed drawings available so

the head can be designed without buying the head can be designed without buying the sensor.the sensor.

SparkplugsSparkplugs

From past experience NGK From past experience NGK sparkplugs have been the most sparkplugs have been the most successful.successful.

The aim was to use a plug with a The aim was to use a plug with a shorter electrode to prevent it shorter electrode to prevent it heating up and causing detonation at heating up and causing detonation at high revs. As of now we are still high revs. As of now we are still working on the decision of which working on the decision of which sparkplug to use.sparkplug to use.

The challenge is finding the The challenge is finding the sparkplug that will allow for a plug to sparkplug that will allow for a plug to injector spray cone of -.08 in.injector spray cone of -.08 in.

Squish VelocitiesSquish Velocities

-90 -80 -70 -60 -50 -40 -30 -20 -10 00

2

4

6

8

10

12

14

16

18Squish Velocity with resepect to crank angle (at 7500RPM)

Crank angle (degrees before TDC)

Squ

ish

Vel

ocity

(m

/s)

Squish Velocity Value RangeSquish Velocity Value Range

2000 3000 4000 5000 6000 7000 80004

6

8

10

12

14

16

18

20Squish Velocity with resepect to crank angle

Engine Speed (RPM)

Squ

ish

Vel

ocity

(m

/s)

Configuration 1Configuration 1

Configuration 2Configuration 2

Configuration 3Configuration 3

Volume Comparison For Config. 3Volume Comparison For Config. 3

Plug to cone issuePlug to cone issue

Original Specs:Original Specs:– 99º injector angleº injector angle– 14º cone angle14º cone angle– -0.08 in cone to plug distance-0.08 in cone to plug distance

Modified specs:Modified specs:– 7-97-9º injector angleº injector angle– 22º cone angle22º cone angle– Electrode touching fuel coneElectrode touching fuel cone

Injector SeatingInjector Seating

CastingCasting

Contacted Eck Industries and D8Contacted Eck Industries and D8Toured D8 facilities talked with owner Toured D8 facilities talked with owner about the possibility of casting:about the possibility of casting:

$3-4k for pattern with approximately 4 week lead time$3-4k for pattern with approximately 4 week lead time$100-200 per casting with approximately 1 week lead $100-200 per casting with approximately 1 week lead timetime

Contacted Travis Pattern and Foundry in Contacted Travis Pattern and Foundry in Spokane. Minimum run of 50 or more.Spokane. Minimum run of 50 or more.Referred By Travis Foundry to Lost and Referred By Travis Foundry to Lost and FoundryFoundry

Sells casting equipmentSells casting equipmentAbility for in house castingAbility for in house castingSetup Cost $400Setup Cost $400

Casting Pros and ConsCasting Pros and Cons

Pros:Pros:After initial investment, After initial investment, cheap and quick to make.cheap and quick to make.

Easy “quick” prototyping Easy “quick” prototyping

Casting knowledge and Casting knowledge and experience gained to experience gained to teamteam

Easier to implement Easier to implement design changes with cast design changes with cast head blankhead blank

Cons:Cons:Expensive initial costExpensive initial cost

Out of house (less Out of house (less control)control)

Time to create first headTime to create first head

Unknown design criteriaUnknown design criteria

Still requires machining of Still requires machining of final surfacesfinal surfaces

Decision points Decision points

Pressure Sensor (6052C or other?)Pressure Sensor (6052C or other?)

Spark Plug typeSpark Plug type

Squish Velocity (Specific RPM or band?)Squish Velocity (Specific RPM or band?)

Combustion Chamber designCombustion Chamber design

Plug to cone distance Plug to cone distance

Manufacturing (Casting)Manufacturing (Casting)

Current BudgetCurrent Budget

PlugsPlugs– $12 each$12 each

ManufacturingManufacturing– CastingCasting

D8 - $4000 initial + $200 per castD8 - $4000 initial + $200 per castLost & Foundry (in house) - $400Lost & Foundry (in house) - $400

– MachiningMachiningMaterial – Billet Aluminum $100?Material – Billet Aluminum $100?Tooling – In house $100?Tooling – In house $100?

BoltsBolts– ARP approximately $100ARP approximately $100

GasketsGaskets– Not yet researched - $100?Not yet researched - $100?

Future PlansFuture Plans

July 10th Design Review July 10th Design Review

July 12th Sparkplugs ordered, pressure sensors July 12th Sparkplugs ordered, pressure sensors chosen. Decide on manufacturing process.chosen. Decide on manufacturing process.

June 17th First Iteration sent to Andy and Justin June 17th First Iteration sent to Andy and Justin for reviewfor review

June 24th Completed iteration sent to Andy and June 24th Completed iteration sent to Andy and Justin for reviewJustin for review

Aug 4th Design Finalized and ready for Aug 4th Design Finalized and ready for manufacture.manufacture.