SFC

REGI U.S., INC. / REG TECHNOLOGIES INC. ANNOUNCE RADMAX® ENGINE TO USE 20% LESS FUEL THAN EXISTING GASOLINE ENGINE

For Immediate Release: June 23, 2008. Vancouver, BC – REGI U.S., Inc. (OTC BB: RGUS, Frankfurt Stock Exchange: RGJ) and Reg Technologies Inc. (TSX Venture Exchange: RRE.V, OTC BB: REGRF) are pleased to announce that based on a recent independent engineering assessment, the RadMax® diesel engine will use 20% less fuel than a gasoline engine, and 50% less fuel than a turboprop jet engine.

Robert Grisar, Vice President of Engineering, states, “The cost of gasoline has become one of the most important issues to North America and having a fuel efficient engine in automobiles and trucks will help reduce fuel consumption, and the demand for oil from offshore, exporting nations.

The engineering assessment, performed by an independent company to evaluate the RadMax® technology, states “The RadMax® Diesel Engine Specific Fuel Consumption (SFC) will be less than 0.4 lb/hp/hr.”

This is a useful parameter for engine comparisons. The SFC is the fuel flow rate per unit power (P) output, expressed as:
SFC = mf / P

To calculate the mass flow (mf), you need to know the mass of fuel. As an example, for gasoline, 1 liter = 740 g (and 1 US gal = 6.17 lb).

Typical average values of SFC for spark ignition, gasoline reciprocating piston engines are 305 g/kW/h = 227 g/hp/h = 0.5 lb/hp/hr.

For a turboprop engine, the typical value is 0.8 lb/hp/hr.

From these calculations, the RadMax® diesel engine uses 20% less fuel than a gasoline (petrol) engine (0.4 vs. 0.5), and half of a turboprop jet engine (0.4 vs 0.8).

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Note from World Most Powerful Diesel

The Wartsila-Sulzer RTA96-C turbocharged two-stroke diesel engine is the most powerful and most efficient prime-mover in the world today. The Aioi Works of Japan’s Diesel United, Ltd built the first engines and is where some of these pictures were taken.

Fuel consumption at maximum power is 0.278 lbs per hp per hour (Brake Specific Fuel
Consumption). Fuel consumption at maximum economy is 0.260 lbs/hp/hour. At maximum economy the engine exceeds 50% thermal efficiency. That is, more than 50% of the energy in the fuel in converted to motion.

For comparison, most automotive and small aircraft engines have BSFC figures in the 0.40-0.60 lbs/hp/hr range and 25-30% thermal efficiency range.

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When I first met Jim he claimed his motor will get 300 miles per gallon in a Caddy with square wheels dragging a parachute.

His explanation was that his engine was only designed to operate at 500 rpm verses 5,000 rpm of the Chevy V8.  Thus he would get ten times the efficiency and his motor would get 0.055 lbs/hp/hr. (0.5/10)

I took that with a grain of salt and started to research the most fuel efficient motors to get and idea of what was actually possible.  So 0.26 lbs/hp/hr would be possible.  At 0.5 lbs/hp/hr an economy car would get about 40 miles to the gallon.  A diesel economy car is up around the 70 mile per gallon range.

So based on that comparison my Rand Cam version would get from 80 to 140 miles per gallon.

This is subject to actual mechanical efficiencies of course, the torque angle of the piston engine is variable between Zero and 90 degrees and thus the 25 to 30 percent efficiency.  The Rand Cam Engine torque angle is a constant 90 degrees, so actual sfc would be lower.

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Why?

Question – Why does the RadMax have such high SFC?

The reason is that overlap is present and occurs because the 30 degrees (360/12) between vanes is less than the total degrees of the cam ie 135 degrees theoretical (180-45).  This causes excessive back pressure. (see Back Pressure in problems)  Jim’s original design had two vanes for 180 degrees between vanes and thus it actually had a pause instead of overlap. When the vane goes past 30 degrees the expanding gases push both forwards and backwards.  Pressure also rises rapidly and energy is quickly converted to wasted heat.