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Scuderi Split Cycle Engine

The first four-stroke piston was developed in 1876. The four-stroke piston arrangement is still the primary design of engines built today.
Today?s engines operate at only 33% efficiency. This means that only 1/3 of the energy in each gallon of fuel is used-the rest is lost through friction and heat.
With over a billion engines worldwide, even small gains in efficiency will have impacts on the economy, dependency on foreign oil and the environment.
A 10% efficiency improvement in vehicle performance would save over $10 billion and reduce emissions of carbon dioxide by 140 million tons per year.
A 20% efficiency improvement could reduce foreign oil used today by 1/3.
Global Warming.
Besides NOx, the extra CO2 leads to violent weather patterns and the melting of the polar icecaps.
The only way to reduce CO2 emissions is to burn less fuel by using more efficient engines.

Split engines appeared as early as 1914. Split cycle engines separate the four strokes of intake, compression power, and exhaust into two separate but paired cylinders.
The first cylinder is used for the intake and compression. The compressed air is transferred through a connecting passage or tube from the compression cylinder into the second cylinder where combustion and exhaust occur.
Gas is compressed in the compression cylinder and transferred to the power cylinder through a gas passage.

 

 

 

The Scuderi Engine was originally invented by Carmelo J. Scuderi (April 13, 1925 ? October 16, 2002). Scuderi Group, an engineering and licensing company based in West Springfield, Massachusetts and founded by Carmelo Scuderi's children, is testing a working prototype of the engine that was officially unveiled to the public on April 20, 2009.

By firing after top-dead center, it produces highly efficient, cleaner combustion with one cylinder and compressed air in the other. 
A conventional cam-actuated valve admits air to the combustion chamber, but a pressure activated disk type valve admits air into the passageway from the compression chamber and prevents it from leaking back onto the intake cylinder.
Fuel is injected directly into the cylinder just as the valve opens.
The highly compressed air whooshes in so quickly and atomizes the injected fuel so thoroughly that the spark is fired to ignite it 11 to 15 degrees after TDC, even when running lean mixtures for increased efficiency.
The power cylinder fires just after the piston has begun its downward motion ("after top dead center", or ATDC). The Scuderi Group says ATDC eliminates a thermal efficiency shortcoming seen in previous split-cycle engine designs. Firing ATDC in a split-cycle arrangement is claimed to eliminate the losses resulting from recompressing the gas.

A Scuderi cycle is a thermodynamic cycle is constructed out of the following series of thermodynamic processes:
A-B and C-D (TOP and BOTTOM of the loop): a pair of quasi-parallel adiabatic processes
D-A (LEFT side of the loop): a positively sloped, increasing pressure, increasing volume process
B-C (RIGHT side of the loop): an isochoric process
The adiabatic processes are impermeable to heat: heat flows rapidly into the loop through the left expanding process resulting in increasing pressure while volume is increasing; some of it flows back out through the right depressurizing process; the heat that remains does the work.

Intake Stroke: The intake stroke in a Scuderi split cycle engine is similar to a conventional 4 stroke engine.
Figure: Intake Stroke

Compression Stroke: During the compression stroke, the charge is pressurized as the piston moves from BDC to TDC in the compression cylinder.
Figure: Compression Stroke

Power Stroke: During power stroke, the charge flows to the power cylinder through the crossover passage as the crossover valve on the power cylinder opens. The charge is ignited in the power cylinder.
Figure: Power Stroke

Figure: Charge transfer initiation. ??????????????????????? Figure: Ignition of charge.

Exhaust Stroke: During exhaust stroke, the exhaust gasses in power cylinder escape through the exhaust valve. At the same time, the intake of charge takes place in the Compression cylinder and the cycle is completed.
Figure: Exhaust Stroke

Although considered bad practice in conventional engine design, firing after TDC in a split cycle arrangement eliminates the losses created by recompressing the gas. The big issue was not how to solve the thermal efficiency problems of the split cycle engine, but rather how to fire after TDC.
In the Scuderi Engine, firing after top dead center is accomplished by using a combination of high pressure air in the transfer passage and high turbulence in the power cylinder.
This high pressure air entering the power cylinder creates massive turbulence.  The turbulence is further enhanced by keeping the valves open as long as possible during combustion.
The result is very rapid atomization of the fuel/air mixture creating a fast flame speed or combustion rate faster than any previously obtained.
Also, the major difference is the efficiency that a Scuderi engine delivers.? A whopping 42.6%!!

• Faster Burn Rate.
• Firing After Top Dead Center Is Counter-Intuitive to Engine Design.
• Lower NOx Emissions- Means It Can Run Leaner and Gain Efficiency.
• Built-In Supercharging- Special Benefits for Aircraft Applications.
• Design Flexibility - Many features that require additional equipment or are just too difficult to implement in a conventional engine design are easily accomplished with a Scuderi Split-Cycle configuration. E.g. Supercharging can be added by simply increasing the diameter of the compression cylinder.
• Piston friction can be reduced by offsetting the compression and power cylinders.  
• Compatibility with existing engine in terms of manufacturing processes and tool requirements.
• High torque at low RPM means higher power at lower engine speeds.
• Same total engine size (number of cylinders and displacement) as comparable conventional internal combustion engines.
• Improved performance and reduced complexity and cost.
• Reduced cost of diesel systems by dramatically reducing three of the most expensive and complex parts of a diesel system: turbocharging, injectors, and exhaust treatment.

• Cool air never enters the power cylinder so heat would quickly build up causing lubrication oils to break down and components to fail.
• Water cooled cylinder walls would be required to resolve this.
• The crossover valve would experience high accelerations so valve train durability could be an issue. This very well might limit the rpm of the engine. Auto-ignition and /or flame propagation could occur in the crossover passage.

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