It is a port-less through-scavenged two-stroke engine.
Click on the above gif animations to dowload the full-size controllable windows exe animation.
With the cylinder-liner rid of intake and of exhaust ports, this engine combines a true "four-stroke" lubrication and lubricant consumption, with uniflow scavenging efficiency and with double valve-area.
Valve-time-area:
A similar four-stroke engine has nearly the same valve-time-area with the PatPortLess (the time halves, but the valve-area doubles) resulting in a similar energy per explosion at the same revs; for every power explosion of the four-stroke they happen two power explosions of the PatPortLess, giving nearly double power.
In comparison to the conventional port-less two-stroke engines (intake and exhaust poppet-valves on the cylinder head, loop-scavenged) the valve-area of the PatPortLess is double, resulting in double valve-time-area at the same revs.
Lubrication:
The piston and the piston rings are lubricated by the crankcase lubricant as in the conventional four-stroke engines, while the working medium is isolated from the crankcase lubricant as the working medium of the conventional four-stroke is isolated from the crankcase lubricant.
In the PatPortless the air sees no more lubricant oil than what it sees in the conventional four stroke engine.
Click on the above gif animations to dowload the full-size controllable windows exe animation of this PatPortLess version; the combustion bowl is formed into the "head" of the single intake valve.
Operation:
The piston comprises valve seats and valve guides.
The piston bears intake poppet valves and restoring springs.
The exhaust valves of the cylinder head are controlled conventionally, for instance by cams secured to the crankshaft.
An intake camshaft rotates in synchronization with the crankshaft (by sprockets, gears etc).
A valve actuator is displaced by the intake camshaft and is restored by restoring springs.
During the compression, the combustion and the expansion, the intake valves move together with the piston, seated on their valve seats on the piston crown.
The right moment the exhaust valves open and the pressure inside the cylinder drops.
At a crankshaft angle the intake valves land on the valve actuator and start following its motion.
Compressed air from the backside of the intake piston enters the cylinder, through the valve-seats / ports on the piston crown, and scavenges the exhaust gas.
The right moment the exhaust valves close.
Compressed air continuous to enter the cylinder until the intake valves land on their valve seats on the piston crown and start following the piston motion.
The compression begins.
The combustion chamber pressure improves the sealing of the intake valves.
Click on the plot to enlarge.
The plot shows the piston motion vs the crankshaft angle (red curve).
It also shows the absolute intake valve motion (cyan curve). For many degrees the intake valve moves together with the piston, as a body, and the cyan curve stays "inside" the red curve.
The plot also shows the intake valve lift (blue curve, continuous line). It is the motion of the intake valve relative to the piston motion. Differently: it is the distance of the piston position (red curve) from the intake valve position (cyan curve).
It also shows the exhaust valve lift (beige curve, continuous line).
The dash-line curves are the intake valve lift (blue) and the exhaust valve lift (beige) magnified by ten times.
Intake camlobe profile:
A good intake camlobe profile has to allow the intake valves to pass smoothly, quietly and reliably from the motion with the piston to the motion with the valve actuator (and vice versa), it also has to protect the intake valves, and their restoring springs, from excessive valve lifts.
Combustion bowl scavenging and cooling:
Click on the above gif animations to dowload the full-size controllable windows exe animation;
here the combustion bowl is formed into the "head" of the double coaxial intake valve;
the small intake valve scavenges and cools the combustion bowl.
PatPortLess with "Crank-Cam" intake valve actuation
Click on the above gif animations to dowload the full-size controllable windows exe animation.
The above plot shows the piston displacement, the displacement of the intake valve actuation pin, and the (magnified by ten times) intake valve lift.
The intake valve lift is the difference between the displacement of the intake valve actuation pin and the displacement of the piston.
Click on the above gif animations to dowload the full-size controllable windows exe animation.
The intake valve is the bottom of the combustion bowl. The small crank (orange) rotates at double speed (relative to the main crankshaft speed) and causes the reciprocation of the intake valve control pin.
Built-in charger.
The backside of the piston can, optionally, be used as a no-cost volumetric scavenging pump / charger. All it takes is a reed valve (or a rotary/sleeve valve on the camshaft, or a disk valve) to trap the air suctioned untill the intake valves open.
The driving of this built-in "charger" involves no friction.
A TwinCharger version:
Similar to the PatOP CrossHead TwinCharger
Flat full balanced:
Click on the image to enlarge.
By counterweights secured on the two intake camshafts, the above even firing opposed-cylinder is full balanced (as much, as the OPOC engine).
The valve timing is as asymmetrical as necessary.
The connecting rods are pulling-rods.
The total length of this flat twin is less than seven times the piston stroke.
