Richard Rodriguez
Gearheads of a certain age likely will conjure up images of automotive entrepreneur Preston Tucker when Dr. Robert A. Knezek and Mike Pastusek lay out their vision for the Continuously Variable Displacement piston engine.
Ever hear of the term “wobble plate”? You won’t find it in either the print or digital versions of Car and Driver or Popular Mechanics. Not yet anyway. But it’s the centerpiece of the engine designed by Dr. Knezek, a retired mechanical engineer, and his co-inventor/nephew Pastusek.
“We’ve been trying to do this for 10 years,” says Dr. Knezek, who retired from General Dynamics, now Lockheed Martin, in 2000 after a near 40-year career that included acclaimed engine work on the F-16 fighter jet.
“Robert retired in 2000,” Pastusek says, “but his brain never retired.”
Enter the AspireCVD engine as touted by Fort Worth-based AmeriBand, LLC. The company’s goal has been to develop an engine that is small, powerful, low-cost, and fuel-efficient using regular, 87-octane gasoline in a bid to significantly reduce hazardous emissions.
“There’s nobody that has solved the configuration that is suitable for actual use,” says the soft-spoken Dr. Knezek, 89, president of the company he founded in 2006. “I don’t know anybody that has ever done that. We have accomplished this goal.”
This engine is projected to be approximately 50% smaller, 50% lighter, and improve fuel efficiency by more than 60%. Displacement of the CVD engine is infinitely variable from 3:1 (1-3, 2-6, 3-9 liters, etc.).
Dr. Knezek’s claim has been backed by engineering design work performed at the University of Texas at Arlington, Texas Tech University, Oklahoma State University, and a private engineering consulting firm. AmeriBand, LLC also has secured six U.S. patents for this technology — although no actual metal, working engine currently exists.
As noted, the CVD employs a wobble plate, a concept used by many hydraulic pumps. The piston stroke, and therefore piston displacement, is changed by altering the wobble plate angle. By moving the wobble plate up or down the power shaft, the compression ratio can be increased, decreased, or held constant throughout a range of displacement volume.
The patented design eliminates the need for timing belts/timing chains while allowing for independent valve timing. In addition, skirt friction induced by pistons in traditional internal combustion engines (ICE) also is virtually eliminated because the piston connecting rod stays almost perpendicular to the cylinder bore. In this engine, the piston connecting rod moves only about five-six degrees. In a conventional engine, a piston connecting rod moves 50-60 degrees.
This technology can be adapted for virtually any ICE use, including the military, long-range trucking, farm equipment, school buses, RVs, boats/marine, and even the wide world of motorsports.
“We can build an engine that will power whatever you want to power, but it’s going to use a lot less [fuel] energy,” says Pastusek, 77, a self-proclaimed “country boy” from Iowa Park who has owned and operated a computerized manufacturing facility since 1976. “This engine would run on diesel; it would run on gasoline. It would run on natural gas, on any combustible fuel. The point is, if we don’t use as much to start with, it’s going to be better for the environment.”
The company’s basic engine profiles list one example with five cylinders that is 13.50 inches in diameter and 18.75 inches long, producing approximately 250 horsepower, and a seven-cylinder engine that is 17.5 inches in diameter and 25 inches long producing about 700 horsepower.
“We started off with a five-cylinder engine,” said Pastusek, armed with a working plastic model of the CVD. “We wanted it to be an odd number of cylinders so it would fire on every other cylinder on a 4-cycle engine (1,3,5,2,4,1…etc.) making for a very smooth-running engine.
“It’s ‘scale-able.’ Basically, it can be as big as you want, and it can be virtually as small as you want. It would even work on a little three-cylinder engine as well. But five or seven [cylinders] would give you a good, smooth-running engine. The engine size will vary based on the demand. If you need more horsepower, more torque, it will increase the stroke by changing the angle of the wobble plate. And if you’re going downhill or idling, it will flatten out to where it has very little displacement.”
The engine’s axial cylinder arrangement features a driveshaft — and no crankshaft. “Getting rid of the crankshaft … to me, it’s the biggest change,” said Dr. Knezek, who obtained his Ph.D. in mechanical engineering from The Ohio State University in 1975.
“The wobble plate is connected to the driveshaft,” said Pastusek, completing his uncle’s thought. “Another difference — because of the cylinder and valve actuator locations and continually firing order every-other cylinder (1,3,5,2,4,1…), there is only one ‘cam lobe’ for all the intake valves and one ‘cam lobe’ for all the exhaust valves.”
The co-inventors claim the CVD’s patented Hydraulic Valve Actuation System virtually eliminates valve actuation system losses typical in conventional engines.
“In addition to the projected 60-plus percent improved fuel economy over a conventional engine,” Pastusek says, “this engine, we believe, will idle between 10 and 20 RPM. So, instead of having your car cut off when you stop, it goes to minimum displacement and RPM because you have virtually no power demand, consuming very little fuel.”
The ideal timetable for launching the CVD, Pastusek admits, would have been 10 years ago. “That was before there was such a big push on electrical stuff,” Pastusek says. “Right now, if you say ‘electric,’ everybody’s raising the [American] flag. And if you say anything about anything else, it’s like, ‘That’s old stuff. We don’t want to talk about that. We don’t need this.’ It was definitely the attitude we were facing.
“But people have come to the realization we’re going to need all forms of energy. And we do need to be as efficient as possible with what we do use.”
Its search for project partners has pointed Team AmeriBand toward the government. AmeriBand manager Brenda K. Reed — Dr. Knezek’s daughter — said the Army has expressed interest in the engine for its ground support vehicles and generators for its “temporary cities.”
Uncle Sam, however, is a cautious customer. “Where we are now, the only engine that we have is a 3D-printed one,” says Reed, 60, whose background is in computer software. “So, all of the tests that have been done through UTA, Texas Tech, Oklahoma State — all those computer-generated tests — have shown that what we’re claiming will happen. But it’s not a physical test. We’re claiming what they said based on their studies.
“That’s where the Army was … ‘When you have real test results, come back to us.’ They’re highly interested in the engine. But they want real tests.”
Pastusek said a prototype engine could be built using many commercially available parts at the AmeriBand compound off Martin Luther King Jr. Freeway. That locale also is home to Pastusek’s D&J Technologies, a full-service precision CNC machining, fabrication, and assembly facility.
“We’ve built engines here before — not like this one,” said Pastusek, who will turn 78 on Nov. 26. “This is just a matter of getting all the final details worked out. And Oklahoma State right now is working with us to help us on these issues — the valve and cylinder system, primarily.”
Dr. Knezek, who will turn 90 on Nov. 12, is a lifespan removed from the farm he grew up on in Megargel, a town in Archer County located on the headwaters of Kickapoo Creek. According to the 2020 U.S. Census, Megargel’s population was 174.
“My father was one of four in his graduating class,” Reed said. “My parents [Robert and wife LaVerne] are going on 67 years of marriage, and one of their wedding gifts was a toaster. And that toaster still works, just because he takes good care of it. Yeah, he’s a smart man.”
Indeed, Dr. Knezek held the positions of project engineer, senior engineering specialist, and program manager during his distinguished tenure at General Dynamics. He served as lead engineer for several projects involving advanced propulsion systems, including as chief engineer for design and integration of the GE F-101 engine into the F-16 fighter jet.
“We were having trouble with Pratt & Whitney supplying the engines. And in a single-engine airplane, that’s not very good,” Dr. Knezek quips. “So, I managed to engage General Electric, and we came up with a modified engine that had originally been designed for bombers.”
Problem solved. Next?
Dr. Knezek’s prescience does conjure up comparisons to Tucker, the Michigan native who challenged America’s automotive establishment with his Tucker Torpedo, aka the Tucker 48. The prototype for the aerodynamic, four-door sedan was powered by a rear-mounted engine and introduced a package of safety/performance enhancements including a padded dash, pop-out windshield, and disc brakes to car- hungry post-World War II America.
The suggestion he might be channeling Tucker — genuine automotive maverick — drew a polite smile from Dr. Knezek. “I hope so,” he said. “I think of our future, and an engine like this has huge potential. I don’t see anything that will keep us from doing it; I’ll just put it that way.”