It is an opposed piston engine: a
cylinder and two oppositely reciprocating pistons form a combustion chamber.
Click on the above gif animations to dowload the respective full-size controllable windows exe animation.
Starting with the Junkers-Doxford engine (heavy unbalanced 2nd order inertia force, long crankshaft especially for multicylinders inline, long connecting rods) and replacing:
- the upper piston and piston pin by a shorter-lighter piston (the piston skirt is only to cover and uncover the ports and not to transfer thrust loads to the cylinder liner) and a reciprocating frame (green),
- the long side-connecting-rods by normal-size connecting-rods at the bottom (not at the sides) of the cylinder,
- the long/heavy wrist pin of the upper piston by a conventional pin that bridges the two lower connecting rods,
the PatPOC engine results.
In case of symmetrical timing of the ports (crankpins at 0 and 180 degrees), the connecting rods remain constantly parallel to each other, resulting in:
-full balance of the inertia forces and moments of the single-cylinder opposed-piston PatPOC basic module (the reciprocating assemblies are of equal mass).
-zero total force on the crankshaft main journals from both: the combustion loads and the inertia loads .
-compact and lighter design: the short crankshaft (the side connecting rods and crankpins can be arranged inside the cylinder footprint because the "green" frame is arranged normally to the crankshaft axis) enables more compact multicylinder arrangements, like the in-line-three, the in-line four etc. For instance, the PatPOC three in-line arrangment allows significant space and weight saving as compared to the old three in-line Junkers-Doxford marine engines.
To further reduce the width of the PatPOC twin (animation at the top of the page) the central main crankshaft journal (which is rid of inertia and combustion loads) can be eliminated, enabling as small as desirable cylinder to cylinder pitch.
In case of asymmetrical timing of the ports (crankpins at 5 and 175 degrees, for instance, for a 10 degrees advance of the exhaust piston), the resulting unbalanced inertia force of the PatPOC is several times smaller than the unbalanced inertia force of the conventional Junkers-Doxford of same stroke and of same reciprocating mass.
The OPOC (Opposed Cylinder Opposed Piston) engine of EcoMotors cannot help causing an unbalanced 2nd order inertia moment created by the offset between the two opposed cylinders; thereby, the vibration-free quality of the PatPOC single-cylinder basic-module is comparable to that of the OPOC two-cylinder basic-module: the PatPOC is slightly better for small asymmetry of the port-timing, the OPOC is slightly better for bigger asymmetry of the port-timing.
The lubrication, the scavenging (electrically controlled turbocharger), the injection, the combustion chamber etc of the OPOC engine fit to the PatPOC engine, as well.
The variable capacity of the OPOC engine (deactivation -by means of special clutches- of some modules in case of partial load operation) better matches with the PatPOC engine, because the full balance of the single-cylinder module of the PatPOC provides more efficient adjustment of the capacity of the engine to the load. The cylinders of the PatPOC are deactivated one-by-one, thereby the PatPOC can run as a single cylinder, a twin, a three cylinder etc engine.
In the EcoMotors’ variable-capacity-engine approach, the cylinders are deactivated two-by-two; this is because each basic module of the OPOC comprises two cylinders.
Special clutches are used for the disengagement; and the power of the distant basic module passes to the load indirectly, through the crankshaft of the next to the load basic module.
I.e. the OPOC basic module the nearest to the load, works overtime.
In case of failure (reasonably, the overworking module will fail first) the complete system halts.
In the pattakon approach (Fig 21) the cylinders are deactivated one-by-one, enabling a closer to the optimum capacity.
With a twin PatPOC at the one side of the primary shaft of the gearbox, and a single PatPOC at the other side, the set can run as either a single cylinder, or as a two cylinder or as a three cylinder engine.
The power of each module arrives directly, and independently, to the load.
In case the one engine fails, the other continues normally for “ever”, improving the reliability/safety of the system.
And they are needed neither special clutches, nor high tech control systems (even a manual system works fine).
Hybrid killer tech?
Consider the case of a sport car having a powerful V-8 engine at the one side of the primary shaft of its gearbox (in the place of the 11, Fig 21), and a small green engine (like the single cylinder full balanced PatPOC or PatOP, or like the Fiat 500 TwinAir) at the other end of gearbox primary shaft (in the place of the 10, Fig 21).
The car can go downtown (and anywhere else the driver likes to go economically and environmentally) using its small green engine.
With the coolant from the small engine circulating into the big engine, to keep it warm, the V-8 is ready, any moment, to power the car (with or without the assistance of the green engine).
The vehicle is way more reliable and cheap-to-run and cheap-to-maintain and green.
The big engine design becomes more uncompromised.
And because it doesn’t need to operate at conditions not matching its character, the big engine will last longer (it isn’t rare: an expensive sport car struggling to idle in the bottleneck, with the rest drivers shutting their car windows to keep the noise out).
Compare this solution to the new sport hybrid cars the sport-car makers launch, one by one, in their effort to comply with the present and future emission regulations.
Judging from the 95 gr CO2 / Km, in the combined European cycle, of the 1030Kp heavy Fiat 500 TwinAir, the sport car, any sport car, can be – according the present regulations – as green and fuel efficient as the best hybrid cars, without batteries, without electromotors, without high tech control and without high cost.
Click on the following gif animation to dowload the full-size controllable windows exe animation.
The mechanism operates with and without the pistons (the piston-skirts of both pistons are rid of thrust loads). The full-crosshead design enables four-stroke-like lubricant-control.
The above full-crosshead architecture fits to the OPOC engine too.
-at the one side of the OPOC the long and well lubricated cylinder liner that receives the thrust loads from the piston skirts (inevitably poor lubricant control);
-at the other side of the OPOC, the crosshead architecture of the PatPOC: the cylinder liner and the pistons are shorter, lighter and rid of thrust loads, while stationary scraper rings (like those shown in the PatPOC-crosshead animation above) keep the lubricant in the crankcase side, as in the four stroke engines.
The PatOP, the PatPOC and the OPOC engines. Click to enlarge.
It is a four stroke PatOP engine.
Click on the image to enlarge:
The same combustion chamber and poppet valves serve both opposed pistons.
Single crankshaft, full balanced, zero loads on the main crankshaft bearings.