Dan Gurney, legendary racer, the man behind All American Racers and designer of the Gurney Alligator recumbent motorcycle, was just issued a patent for a new engine design. It's an upright parallel twin with counter rotating cranks called the "Moment Cancelling 4 Stroke." It's initially aimed at motorcycles, though he suggests it could be used in many other applications in the future. The first engine will displace 1800cc or 110 cubic inches. Current plans are to build five prototypes with the first running on the test stand later this year.
Gurney worked closely with Chuck Palmgren who was an AMA Grand National Flat Track and Road Race competitor. Together they came up with a list of requirements for the new engine:
- Trouble free operation for long time endurance
- Robustness under harsh conditions
- Outstanding efficiency
- Outstanding emission reduction
- Outstanding mpg
- California 91 Octane fuel not a problem
- Low parts count
- Low manufacturing costs
- User friendly power “flywheel”
- Very good power, naturally aspirated with 9.5 compression ratio
- Two buttons, two modes: (1) For best miles per gallon (2) another for best power
- Light weight
Running the design in their simulation program predicts impressive output, even though power was pretty low on the list of design goals.
Vertical twins with their inherent rocking motion do have the advantage of compact size, but this moment cancelling design certainly has the potential to make them smooth runners, as well. It should be interesting to see the development of this engine as it progresses. Heck, it will be neat just to see it fire up later this year.
UPDATE: I initially linked to the incorrect patent. Fixed now.