CVPD™ Proof of Concept
(Constant Volume Piston Dwell)
PURPOSE
The prototype was constructed to demonstrate the increase in both volumetric and mechanical efficiencies of the CVPD™ technology compared to conventional engine designs.
DEFINITION
Figure 1.1 (photo) shows a static (non-combustion) prototype of both conventional and CVPD™ technologies. The assembly on the right is of conventional design representing an engine with a piston, connecting rod, and crankshaft. The assembly on the left is our new CVPD™ design which also includes a piston and crankshaft and the means to connect the two components as defined by the technology. Both assemblies utilize an equal connecting length of 6.00”.
Each assembly uses identical 3.25” bore air cylinders and 3.25” stoke crankshafts. Air cylinders were used for easy control of applied pressures and to demonstrate that the design works with any pressurized gas whether derived internally or externally. A main pressure regulator with a pressure gauge controls air pressure. Independent cutoff valves provide a means to isolate each assembly.
A pin and pin dial is used to remove the human element when measuring applied torque. Torque is measured using a digital torque wrench resting on the pin which is inserted into the dial.
Figure 1.1
PERFORMANCE
Volumetric increases – in conventional engine valve timing, the intake valve closes at some degree after BDC. Closing the intake valve after BDC reduces the displacement of the engine. This is possible due to the ram air effect (momentum) created by the piston as it moves from TDC to BDC. In contrast, the CVPD™ technology holds the piston at maximum displacement (BDC) to take full advantage of the ram air effect. Additionally, the overlap between the exhaust valve closing and the intake valve opening causes a reversal in the direction of the gas streams in both intake and exhaust manifolds. This reversal must be overcome before proper flow of gas (air) can enter the cylinder chamber. The CVPD™ valve timing includes zero overlap thus eliminating flow reversal. (Please note: our design generates a higher degree of ram air effect due to the fact that our piston’s speed will be twice that of a conventional piston.)
To demonstrate our advantage we assume a valve closing of the conventional design to be at 60-90° ABDC, respectively from idle to full power of variable valve timing systems. By comparing the compression generated by closing the conventional assembly’s valve at 0-60-90° ABDC, we can demonstrate our volumetric advantage irrespective of the ram effect.
Table 1.1
COMPRESSION RESULTS @ DEGREES ABDC (Atmospheric + 10 PSIG)
INTAKE VALVE CLOSED COMPRESSION (PSIG) INCREASED EFFICIENCY
0° (New Design Always @BDC) 150 ------
60° (Low RPM, Low Power @ABDC) 121 124%
90° (High RPM, High Power @ ABDC) 92 163%
Geometric increases - conventional designs transmit energy from the piston to crank through a series of compound angles. Our technology also transmits the piston’s energy to the crank through an angle but with an additional mechanical advantage, in part, due to the piston’s travel from TDC to BDC over 90° instead of 180°. To document geometric advantages we measured each assembly’s output torque at every 10° when pressurized to 80 PSIG at TDC. The CVPD™ true advantage, when taking into account piston dwell while pressure peaks, is illustrated by pressurizing the piston to 80 PSIG at 90°. Graph 1.0 presents the results. Tables 1.1 & 1.2 document the actual readings. (Note: we elected to lessen the length of dwell in our prototype for presentation purposes and ease of physical manipulation.)
GRAPH 1.0
LEGEND:
CONVENTIONAL at 80 PSIG @ TDC. (Actual Mechanical Advantage)
CVPD at 80 PSIG @ TDC. (Actual Mechanical Advantage)
CVPD at 80 PSIG @ 90 ATDC. (Theoretical Operational Advantage)
Table 1.2
TORQUE RESULTS @ 80 PSIG = 663.7 Lbs Force @ TDC
TDC OLD (In-Lb) PSI Cyl NEW (In-Lb) PSI Cyl OBSERVED MAX.
10° 198 70 0 80 0 80
20° 276 66 0 80 0 80
30° 280 42 0 80 0 80
40° 245 31 22 79 23 80
50° 200 24 34 77 40 80
60° 152 18 62 72 83 80
70° 112 12 127 66 220 80
80° 80 10 290 55 649 80
90° 53 8 471 40 1068 80
100° 36 5 393 24 922 69
110° 0(1) 244 15 710 53
120° 0 166 10 542 41
130° 0 105 8 384 29
140° 0 61 6 273 21
150° 0 43 4 182 14
160° 0 0(1) 111 8
170° 0 0 50 4
180° 0 0 0 0(1)
(Actual peak)
Note 1: Exhaust valve opens
CONCLUSION
The pure mechanical advantage increases at peak pressure is given as (471/280) 168.2%. Adjusting for volumetric increases we would obtain 208.6% and 274.2% respectively. The increases in the ram air effect will add to these numbers but can not be demonstrated by this prototype, therefore not included. From the data in the table, when the POC prototype is held closer to release at 90°, the mechanical increases equal (1068/280) 381% at peak. Again, when we adjust for the volumetric increases we see yields of 472.4% and 621% respectively.
Valdese, NC 28690
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