Or
Uniport Valve
This
simulation compares a Uniport Valve head (using it alone) to a
conventional two valve head. Following is a brief summary of some of
the things that were accounted for in the simulation.
1) The port in the UniPort Valve simulation was approximately 60% bigger than the intake port of the Two Valve simulation.
2)
I assumed the flow through the ports in the Two Valve simulation to be
decreased by 10% due to shrouding effects, while assuming none for the
Uniport Port Valve.
3) Heat losses were computed ignoring losses due to radiation.
4) friction losses were assumed to be 10% of the heat of combustion delivered to the engine.
5) Valve timing was adjusted for each design to obtain maximum power when the engine operated at 6000 RPM.
6)
The simulations used the same combustion efficiencies and flame travel
times, even though I believe there could be improvements in both by
using the Uniport Valve.
Engine Specifications Used for
Simulations
Supercharged, SI, Four Cycle - Gasoline Engine
Number of Cylinders= 8
Displacement = 361.9 cubic in.
Diameter of Bore= 4.00 in.
Stroke Length= 3.60 in.
Connecting Rod length= 5.76 in.
Compression Ratio= 10.0
Pressure in Intake Runner= 1.65 atm
Temp. of Incoming Air= 29.4 C
Combustion Efficiency= .978
Equivalence Ratio= 1.0
Uniport Valve Two
Valve
Simulation Simulation
port area for intake gas 4.06 sq. in. 2.45 sq. in.
port area for exhaust gas 2.46 sq. in. 1.79 sq. in.
degs bBDC ex. valve opens 80 degrees 90 degrees
degs bTDC exhaust closes 5 degrees -2 degrees
degs bTDC intake opens 5 degrees 8 degrees
degs aBDC intake valve closes 29 degrees 34 degrees
Computer Simulation Data for:
Supercharged, SI, Four Cycle - Gasoline Engine
Running at 7,000 RPM
Uniport Valve Two Valve System
thermal efficiency = 24.9 % 22.9%
volumetric efficiency= 1.716 1.41
heat
losses= 311.
hp 306. hp
break horsepower= 690. bhp 496. Bhp
