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
- Reliability
- Robustness under harsh conditions
- Outstanding efficiency
- Outstanding emission reduction
- Outstanding mpg
- California 91 Octane fuel not a problem
- Low parts count
- Low manufacturing costs
- Simplicity
- User friendly power “flywheelâ€
- 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.
All American Racers MC4S and patent
UPDATE: I initially linked to the incorrect patent. Fixed now.
todd says
That’s cool and all bit didn’t Ariel, Kawaski, and Buell (and others) do the same?
Alan Hoffmann says
My initial observation, torque should be excellent, vibration will be reduced dramatically translating into enhanced reliability, I would focus on those attributes. I am thinking that horse power would be slower to build unless more cylinders were added at different degrees to reduce the dead zones allowing power to build more easily, reduce momentum reductions. My thinking anyway from the illustrations.
Alan Hoffmann says
Just a thought, develop a head with a gear driven rotary port shaft, make it a two stroke. Like a two stroke, power would double and if the shaft, chamber and pistons were designed correctly, you may not need reed valves. Using a reed valve on the intake would prevent back pressure and disruption of air flow, in normal two stroke applications. Such a configuration would increase horse power dramatically by keeping the momentum flowing, verses a four stroke.
zipidachimp says
way cool for an 80-something to be designing new engines! Gurney for president………er… ok we did that!
Ed says
Well now, if the diagrams are drawn to confuse, as some patent diagrams are, then it has accomplished those goals. At least it did for me.
The first diagram shows a 4 cylinder top end with double overhead cams mated to a twin cylinder bottom end. The cam drive for this feat seems to be driven by a system that is at right angles with the bottom end.
Then the diagrams in the patent show what at first glance looks like a rocker box on the top of the engine, but then it looks more like a feed for a supercharger.
Anyway, I do not see how one would reach the valves in order to adjust them.
Fig. 3 in the patent shows two separate heads, but all of the other figures show one block.
I do not understand how a patent could be awarded from these drawings! However, maybe it is just me that is confused.
Ed
Paul Crowe says
I’m rechecking the patent that I linked to.
Paul Crowe says
Fixed. The patent I linked to at first was a reference link to a related patent, evidently. The images should make more sense now.
Frits Overmars says
How do you get a 2015 patent for an engine layout that was built in 1939?
http://www.velocette-amateur.com/proto.htm
Paul Crowe says
I quickly scanned the patent and there seems to be a lot of reference to the airflow and combustion characteristics of the engine, over and above the counter rotating cranks, so that may play a significant part in making it unique, though reading patents is a painful process so there may be more to it than that.
Huib van den Doel says
Indeed, there is nothing new in counter-rotating cranks. The Velocette Roared had them prewar, Rotax and Kawasaki used them on twostroke twin racers – although Kawasaki had to discover them the hard way – they only found out when the prototype with 180 degree firing interval vibrated itself apart.
Is Gurney trying to get some Selden-like patent with the US Patent Office aiding and abetting?
Wave says
Doesn’t the Ariel Square Four also have counter-rotating crankshafts?
And what about this US patent filed in 2007 by Ford Global Technologies? http://www.google.com/patents/US7533639
Paul Crowe says
It will be interesting to closely examine the Gurney patent and see what the sufficiently unique design characteristics are in the new engine. Patents are a minefield of prior art and intellectual property, endless conflicts in court and arguments about who was first, but clearly, counter rotating cranks by themselves have been around for a long time.
Geoff says
The Germany company Neander produce (or used to) a diesel powered motorcycle with this arrangement, see http://www.neander-motors.com
Paul Crowe says
They used two rods on two crankshafts, but both were connected to a common piston.
Ton van Hulten says
Motoczysz built an engine with two logitudinally placed counter rotating crankshafts on the C-1 prototype 4-cilinder fourstroke racer. It had two separate cilinderheads. The second model had one plane cilinderhead.
So what’s new?
Doug says
Isn’t the diagram on the left mis-labelled as the “Front” ? That diagram looks like it is depicting the left-side of the engine, not the front (based on the location of the transmission). This orientation would make a very slim design in a bike….as slim as a thumper.
The diagram above-right then would be depicting the rear of the engine, not the right as the diagram states.
Paul Crowe says
I thought I had it figured out, but after looking at that again, …
Doug/Drive The Wheels Off says
The twin that has the narrow fit of a thumper with the smoothness in the realm of a boxer would be very cool. This motor has my attention
Bob says
I get the impression that he wants a new American twin that doesn’t behave like an old American twin.
Cool!
And if this is what people can do when they are 80+, hey, the next few decades look a lot more fun than I feared. Dan Gurney: Role model.
PS: Will style and fashion motorycle “writers” approve? What is the bespoke pipewrap coefficient? Or the authenticity/soul ratio? How will it appear in badly lit photos with dismal/disarrayed backgrounds? Millions of online non-participants in this lifestyle/sport need to know before the next post!!!!
R J Boughton says
how can this design be patented? Its a direct copy of the Velocette Roarer. Its also half of an Arial Square 4. I dont think it would take to much research to find other geared crank parallel twins
Huib van den Doel says
Granville Bradshaw designed one for Panther just prewar. So in a European court this patent would be thrown out in the first hearing. But it seems US judges have some strange ideas about their jurisdiction…
lennard schuurmans says
More information on Gizmag about this patent.
interesting part of the post:
“The intake port has a “double tapered” cross section, as its diameter gets thinner in the middle section, forcing the flow to accelerate, before gradually expanding to meet the exact valve seat size. Playing around with small variations in intake port diameter and inclination, as well as valve seat angles, results in what Gurney calls the “optimized taper configuration” and some astonishing output results.
The first prototype engine to be built will be the liquid-cooled tandem twin (pictured above), with a displacement of 110 cubic inches (1,800 cc), two overhead camshafts and four valve heads. According to the simulations that Gurney has run, the MC4S engine with a standard straight intake port will produce 141 hp (105 kW), while the output of the very same engine with the special porting system skyrocketed to 262 hp (195.4 kW); that’d be an 85 percent increase, from a naturally aspirated engine burning normal pump fuel. According to the patent text, this is simply the result of delivering the air deeply and efficiently into the bore to enable a more efficient combustion process.”
Read the rest of the article here:
http://www.gizmag.com/dan-gurney-moment-cancelling-motorcycle-engine-patent/39344/
Joe says
As I recall the introduction of the Motoczysz counter rotating four cylinder that Michael Czysz had hoped to compete with in Motogp, I also remember an insightful criticism from designer James Parker.
In spite of it’s purported potential for superior cornering especially in transition because of the engine’s gyroscopic neutrality, Parker said that it would never be able to overcome the additional parasitic frictional losses that are inherent in the design and would fail to produce enough power to be competitive with the displacement limitation that Dorna had in place in the rules.
I think he was right and I think that is the primary reason why it never competed.
Maybe this layout is better suited for a large displacement twin and a standard or cruiser style bike rather than the limited displacement superbike .
It’s got great compactness though which should give a bike with a well designed chassis wonderful handling and with it’s large displacement, plenty of power.