Heads Under Pressure

Heads Under Pressure

Nick Harker

Chris Tockey

Peter Britanyak

Design Project: Instrumented Head for the Clean Snowmobile Challenge

Project Goals:

• Head Re-designed with pressure sensors for in-cylinder pressure data.

• Modify the combustion chamber to given specs.

Combustion Chamber dimensions and Specs

• Dome radius .75 inches • Cone to plug distance is -.08 inches • Squish velocity of 15-20 m/s • Squish diameter of 1.95 inches • Squish radius from cone to squish .25 inches (double turbo head) • No dome offset

• Squish area same as turbo head 34% • Dome height approx. 1 inch as necessary for compression ratio • Dome angle needs to be determined for the correct compression ratio • Compression ratio of 6.5:1

Design comparison 2004 to 2006Parameter 2004 Design 2006 design Why?

Injector Angle 11 5Injector aimed toward intake to inhibit unburnt fuel leaving though intake port.

Squish Diameter 1.75 1.81 Increased for efficiency.

Squish Area % 41% 39.50% Similar to last design.

Dome Offset .05" 0 Centralized dome allows centralized combustion.

Dome Height 1.25 1.06 Decreased with increase in dome height.

Dome Angle 59.5 59.64 Similar to last design.

Dome Radius 0.4 0.7 Better nozzle geometry for symmetrical fuel cone.

Squish Radius 0.04 0.25 Increases work done on piston.

Plug Distance from Top of Chamber

0.65 0.47Designed for sparkplug to be half the distance from the injector to bottom.

Sparkplug to Fuel Cone Distance

-0.08 0.02The increase in dome radius moved the sparkplug out. The grounding strap is in the fuel cone and the electrode is .02 from the fuel cone.

Compression Ratio 6 6.5 Staying with stock compression ratio.

Combustion Chamber volume

33cc 26cc Must be the same to conserve compression ratio

Combustion Chamber Iterations

Drawing showing the location of a regular and extended electrode

Sparkplug boss protruding into combustion chamber

Final iterations of unsymmetrical combustion chambers to bring the sparkplug electrode into the fuel cone

Final Design for Polaris 600

Injector and Sensor Boss

Injector and sensor boss passes through the cap to reduce the over all height.

Skidoo 600 Head Design

Skidoo sled will be much easier to adapt to our system

Skidoo Head

Skidoo Combustion Chamber

Polaris Combustion Chamber

Water Jacket Comparison

Skidoo Head Polaris Head

Current Progress

• Head designed

• Aluminum stock arrived

• Received Kistler pressure sensor tools

• Received ARP head bolts and gasket material

Current Tasks

• Get solid model approved for manufacture Sept. 19

• Complete MasterCam Oct. 9

• Begin machining Oct. 11

• Testing End of Oct.