Computer Simulation
for a
Compounded Dual Pressure Intake Diesel Engine
That Uses
A Double Acting / Uniport Valve
(Patent #5,782,215)
2-23-06

This simulation compared the performance between two engines that use the same block but use two different heads. The "Baseline Engine" used conventional valves and the proposed engine, a "Compounded Dual Pressure Intake Diesel Engine", used three conventional valves along with a Uniport Valve.

1) The Standard head simulation used a turbocharger, which had a turbine intake pressure (back pressure) of 2.1 atm. The turbine powered a compressor that delivered air at 2.25 atm. The Dual Intake simulation had a turbine intake pressure (back pressure) of 2.1 atm and it has two intake runners. One delivers air at 1.825 atm and the other one delivers air at 2.625 atm (the average of these being 2.25 atm). The dual pressure simulation uses two compressors two deliver the two pressures. The compressor that delivers the 2.625 atm air gets its supply air from the other compressor.

2) Convection heat losses were computed. Radiation heat losses were not. Though this is a significant form of heat transfer in a diesel engines, it is thought that any error in this omission would effect both simulations similarly.

3) Friction losses were assumed to be {1.5%+3%/(volumetric efficiency)} of the heat of combustion of the fuel burned. Where volumetric efficiency is defined as (mass of air in cylinder after inlet valve shuts)/(mass of air in cylinder at standard pressure and temp.)

4) The simulations used the same combustion efficiencies and flame travel times although it is thought the dual intake system may aid the combustion process.

5) It was assumed any extra turbine work that the compressor or compressors did not consume could be considered useful work.

6) There are after-coolers on both engines. And on the dual intake simulation there is intercooling done on the air coming into the high pressure compressor.

7) Valve timing for the baseline engine was adjusted to get maximum power at 900 rpm. The valve timing for the dual intake simulation was adjusted at the same engine speed, but power optimizing was stopped before the thermal efficiency dropped below that of the baseline engine.

8) In the Dual intake simulation the high pressure air is mostly introduced to the cylinder at the end of the intake cycle. However the nature of the Uniport Valve makes it is easy to allow some of the high pressure air into the cylinder at the very beginning of the induction cycle to help with scavenging.