2 cycle engine

The 2-cycle engine eliminates most of the cycle limitations — in some circumstances, the 2-cycle engine has a higher thermodynamic efficiency and output ratio than a 4 cycle engine does. Watch video on 2-cycle engines here.

Hybrid electric vehicles use combustion engines to generate electricity and improve efficiency. Learn more at ecogeek.org the image below will help you understand how a 2-cycle engine works. Learn more at HybridAirTrucks.com or visit Larry-Shultz.Blogspot.com



Larry Shultz is a Investor and Inventor of Clean Energy Products.

More Efficient for Generating Electricity

Clean energy

Increasingly frequent heat waves and droughts tied to climate change are hurting the electricity sector.  According to the NY Times Green Energy Blog, “as temperatures rise and the climate gets warmer, so do the rivers and lakes that power plants draw their cooling water from. And that is going to make it harder to generate electricity in decades to come, (when) the water will be too warm to allow full power production.”

Increased drought conditions from hot weather reduce river and lake water availability, further reducing water supplies and reducing Coal-fueled and combined cycle power generation.

Power plants that burn coal or use nuclear fission, and most of the plants that burn natural gas with a combined heat-recovery system, use their heat to boil water into steam, which spins a turbine that turns a generator to make electricity. Then the steam has to be cooled and condensed back to water before being reheated again.


If the river or lake water used to cool and condense steam is getting warmer, then the amount of steam it can condense is reduced, leading to a decline in electric power output, especially during the summer when electric fan and air-conditioning power demand is high

Electricity production by coal, nuclear and natural gas power plants is the fastest-growing use of freshwater in the U.S., accounting for more than about ½ of all fresh, surface water withdrawals from rivers.

In 2012, some U.S. power plants had to cut electricity production because of low water levels or because water was too warm to cool nuclear reactors. The National Oceanic and Atmospheric Administration said the period from August 2011 through July 2012 was the hottest 12-month period on record in the U.S. since 1895.


In addition to fouling streams and drinking-water through mining and coal-ash dump sites, coal-fired power also relies heavily on closed-loop cooling systems, withdrawing 500-600 gallons of water per MWh. Most of this is then lost via evaporation.

Withdrawals for open-looped cooled coal-fired power plants are between 20,000-50,000 gallons per MWh.  While most of the water is returned, it’s at a higher temperature and lower quality.


Linear Engine Solves Problems

Free-piston kinetic engines have been the subject of intensive research during the past twenty-five years and many engine manufacturers tried to build commercial free piston engine models because of its attractive features, such as increased weight to power ratio and reduced frictional losses by the elimination of a heavy crank shaft with substantial vector angle losses.

Over time, all of them gave up, primarily due to faulty actuation methodology after failing to develop suitable actuation means of timing and running the engine. There are many prior art patents that describe various means to actuate a free-piston engine such as slide valves used by old steam engines with problematic mechanical connections, poppet valves, reed valves, timing cams, electrically operated solenoid valves, and pressure actuation methods using a slave piston and cylinder designed to produce pressure differentials as the engine runs to drive an actuator assembly, and many other prior art attempts at actuation— all having substantial limitations.

Prior art kinetic engines of the electrically operated solenoid valve design are extremely problematic because they over-heat with continuous use of over a few hundred cycles per minute as heat builds up in the resistance coils, they require a supply of electricity to operate, require an electronic control module, and need proximity sensors to operate.

Prior art free-piston kinetic engines of the pressure-actuated design have a substantial number of severe problems, such as the location at which actuation takes place varies with changes in temperature and pressure. Even when the engine does actuate, often it is not at the desired stroke length with the piston stoke being too short or too long.

All of these problems encountered by prior art free-piston engines attempts have been eliminated by the U.S. Megawatts Linear Engine and its novel exhaust-actuated means of timing, whose advantages are:

(1)    No electricity is required to start or operate the kinetic engine; and,

(2)    Capable of attaining high speed, high flow rate precision actuation; and,

(3)    The site of actuation is exactly established by the position of the exhaust ports at the end of the desired piston stoke length; and,

(4)    The full force of the working fluid is available for actuation; and,

(5)    Full actuation takes place as the movement of the actuator cylinder must be sufficient to open the actuator exhaust ports in response to the pressure differential from the working fluid’s higher pressure to the lower exhaust pressure; and,

(6)    Elimination of compression pistons cylinders needed for prior art pressure actuation means of timing, which means fewer moving parts are required; and,

(7)    Increased power to weight ratio; and,

(8)    Reduced frictional losses by elimination of the heavy crank shaft with substantial vector angle losses; and,

(9)    Lesser parasitic engine power losses due to the elimination of the slave pistons and cylinders for prior art pressure actuation that consume substantial power.


Cost & Performance Advantages of U.S. Megawatts Generators Over Recip Engines & Gas Turbines

The U.S. Megawatts Generator offers significant price and size reductions on a normally high-cost product that no responsible CEO or CFO  can afford to ignore. The Linear Engine-based U.S. Megawatts Generator holds the potential to be nearly 20% more efficient and 50% less-expensive than a Gas Turbine generator.

As coal-fired power plants and property owners with a natural gas connection realize they can lower their operating costs and increase their profits by fuel-switching to natural gas-generated electricity – they are going to seek out the lowest-cost natural gas-fueled electric generating equipment they can find.

The U.S.  Megawatts Generator offers a lower-cost higher-performance alternative to retrofitting their power plants with the same old expensive Natural Gas Turbine Generators — made by GE, Siemens, Mitsubish, Alstom or other turbine-makers  — at costs > $1,000,000 per MW.

While a turn-key 100-MW GE or Siemens Gas Turbine facility will cost >$100-million – a 100-MW Linear Engine-based U.S. Megawatts Generator would cost approximately $50-million – half the cost of a turbine.

Gas Turbines are twice as expensive as a Linear Engine-based U.S. Megawatts Generator because Gas Turbines are more than twice the size, much more complicated to build, are sensitive to operate, and prone to turbine blade failures that are expensive to fix.


Because of its market disruptive price differential, U.S. Megawatts, Inc. managers believe they will be successful in capturing a significant share of the market by selling their simpler, lower-cost and more efficient Linear Engine-based U.S. Megawatts Generators direct to budget-minded CEOs/CFOs of the major electric power producers in the USA and worldwide that are fuel-switching from Coal to Natural Gas – and direct to large end-user electricity-customers (factories, shopping centers, retail superstores and other local property owners) who are connected to a natural gas meter and want to lower their cost of electricity.


Because many of these companies’ executives have fiduciary duties to their shareholders to save money, save time, save energy and reduce emissions – they will be more inclined to adopt use of a just-as-effective U.S. Megawatts Generator at one-half the cost of a Gas Turbine alternative.

Switching From Coal to Natural Gas.  With the EPA’s Mercury and Air Toxics Rule (aka “Utility MACT”) and the Cross State Air Pollution Rule (CSAPR) regulations in effect, it will become prohibitively expensive for America’s Coal-fired power plants to sufficiently clean up their emissions.


The rules require new plants to emit a maximum of 1,000 pounds of carbon dioxide per megawatt hour. While the newest natural-gas-fired power plants emit about 800 pounds of carbon per megawatt hour, new coal plants emit 1,600-1,900 pounds per megawatt hour (requiring additional expensive pollution-abatement costs).

According to EPA modeling and announcements from electricity producers, nearly 35 gigawatts of electricity capacity will close because of these two rules.  At-risk plants that may be uneconomical to upgrade represent about 70,000 megawatts of generating capacity. These at-risk plants provide about 9.3% of total US electric power generation .


For the 570+ coal-fired power plants in America offering 315-gigawatts of on-demand power, one-third began operating between 1940 and 1969, and it may not be economically viable to install  emission scrubbers and state of the art pollution controls to clean up their emissions – especially when, for almost the same money, they could upgrade their facility to burn cleaner, cheaper natural gas instead.


The average emissions rates in the United States from natural gas-fired generation are: 1135 lbs/MWh (Mega Watt hours) of carbon dioxide, 0.1 lbs/MWh of sulfur dioxide, and 1.7 lbs/MWh of nitrogen oxides.  Compared to the average emissions from burning coal, natural gas produces half as much carbon dioxide, less than a third as much nitrogen oxides, and one percent as much sulphur oxides.

While U.S. coal prices have increased by more than 70% in the past decade (inflation adjusted), the monthly average price for Natural Gas delivered to electric generators is at a 10-year low, due to America’s new abundant 100-plus-year supply of fracked shale gas, whose price is expected to remain at <$4-$5 per mmbtu (perpetuating the supply of lower-cost electricity).


Electricity from a conventional coal-fired power plant costs 9.5 cents/per kilowatt hour to produce, compared with 6.6 cents at a conventional modern gas plant, according to EIA’s Energy Outlook 2011.

This is why the electric industry is switching from Coal to Natural Gas as their preferred fuel of choice.

In 2010, coal-fired plants produced 340,000 megawatts of electricity, or 45 percent of total U.S. electricity production.

For the first time since the EIA began collecting such data, the percentage of electricity generated from natural gas-fired power plants is equal to (and overtaking) electric generation from coal-fired plants.

Each fuel now provides over 96-million megawatthours of electricity, or 32% of total electric generation in the USA.

With the cost of coal-powered electricity now being twice that of natural gas, the economics of natural gas has dethroned coal as the nation’s key source of electric power.  U.S. Megawatts, Inc.’s natural gas-fueled Linear Engine-based U.S. Megawatts Generator will be the lower-cost and higher-performing alternative to today’s more expensive but less-efficient diesel-fueled and natural gas-powered reciprocating engine-generators and gas turbine-generators.

U.S. Megawatts, Inc. anticipates strong demand from Coal-fired power plant owners.  U.S. Megawatts multi-MW sized Generators will cost significantly less than, and offer performance advantages over, their more complicated, expensive competitors (GE, Siemens and Fuji) offering Gas Turbine Generators.

U.S. Megawatts, Inc. also anticipates that increased demands on the nation’s centralized electrical power systems and incidences of electricity shortages, power quality problems, rolling brownouts, weather-related blackouts, and Coal-based electricity price spikes will encourage more and more residential and business customers of the local Electric Utility to install their own (or buy electricity from) on-site, lower-cost, natural gas-fired kW-sized U.S. Megawatts Generators.

Rather than satisfy increasing electrical needs by building more large centralized power plants and long-distance transmission lines that are expensive and lose energy along the way — building smaller localized power generators close to, or at, the point of use is more efficient, reliable and cleaner.

Note the 73%  loss of energy for existing Electricity Distribution system and retention of 90% of the energy using natural gas to generate power on-site, where the power is needed.  This confirms the need to generate on-site power using natural gas.

While there are various Distributed Energy and Alternative Energy resources available — not only are all of the Renewable Energy (Geothermal, Hydroelectric, Wind and Solar) technologies more expensive to permit, build and operate than natural gas-fueled electric generators, but Wind and Solar power systems operate intermittently, and are unable to provide a reliable always-available, baseload power source that consumers demand (because the Sun does not shine and the Wind does not blow almost 2/3 of the time).

This is why natural gas is the most logical, lowest-cost option for new electric generation capacity in America.

Of the more than 580 coal-fired power plants still in operation in the USA, 341 are operated by electric utilities, 100 by independent power producers, and the remainder by industrial and commercial electricity producers.

The Linear Engine-based U.S. Megawatts Generator is scalable to virtually any power output,  from portable kW units to fixed-site MW units– limited only by the pressure and volume of the input energy source (which defines the optimum piston diameter, cylinder stroke length, SPM strokes-per-minute speed and exit pressure output to generate rotary shaft torque).

Diesel-Fueled Engines

When one considers that a multi-MW natural gas or diesel-fueled reciprocating engine is >4 times larger than an equivalent output Linear Engine (and a natural gas turbine engine is >2-times larger) and twice as expensive – it becomes evident that the much-smaller Linear Engine-based U.S. Megawatts Generator will enjoy substantial cost and weight savings compared to these hulking machines:

         GAS TURBINES                 RECIPROCATING ENGINES                LINEAR ENGINES




Gas  Turbines   are   expensive because they require complex turbine blades  and associated sophisticated sub-systems.


A Linear Engine can be built at low cost because it uses off-the-shelf,  standardized and commoditized hydraulic system components (high pressure cylinders, pistons and computer-controlled valves) that are widely available and easy to modify for the Linear Engine’s purposes.


These piston and pipe components scale up very well to much larger and heavier sizes (think maritime and oil industry applications), with the largest MW output sized components getting built at the lowest per-kW cost.

Natural Gas + Compressed Air = New Hybrid Electric Generator Technology 

The Linear Engine has the potential to become one of the most fuel efficient yet powerful high-torque engine generators commercialized because it combines the following patents-pending innovations:



  • a long piston stroke measured in feet, rather than inches (as in recip engines), which offers much larger compressed air volumes and positive displacement and residence time inside the cylinders to completely combust natural gas with the lowest resulting emissions and fuel consumption (while cost-effectively producing >500-5,000 foot-lbs of torque to power kW kilowatt-sized electric generators (for homes and small businesses) and MW megawatt-sized generators (for power plant operators and large businesses).
  • a  novel  Free-Piston  Exhaust  Actuation  method  that solves the dual-piston control, piston-positioning accuracy and piston-landing problems that plagued previous free-piston engine attempts of the past (which the U.S. Megawatts Linear Engine overcomes with precision control and variable compression),gear
  • a novel external air compressor stage that allows significantly  larger volumes of intake air (at on-demand compression ratios) to be compressed and expanded in two-strokes, rather than the four strokes required by gasoline and diesel recip engines (whose short-stroke pistons severely limit the volume of air they can intake before their compression stroke).
  • a novel Sprague-Gear Transmission with perfect 90-degree vector angle power take-off that avoids the more than 50% mechanical efficiency losses suffered by conventional short-stroke reciprocating piston engines (whose heavy camshafts, crankshaft, flywheel and bearings, are eliminated in the Linear Engine).

Having a larger supply of compressed air,  a much lighter, but longer piston stroke and a more efficient means of power takeoff creates a much more powerful and cleaner-burning natural gas engine than any other internal combustion natural gas powered engine on the market today.

Sprague Gear Transmission


Instead of using a centrifugal or piston-type compressor, the Linear Engine-based U.S. Megawatts Generator employs a twin-screw multistage compressor whose specifications confirm that 20% of the Linear Engine’s gross power output will be consumed by the parasitic load of the screw compressor.

This equals half of the parasitic energy needed to compress air in  a typical Gas Turbine engine that costs twice as much.

With its natural gas-fueled 1-MW to 100-MW Linear Engine-powered electric generators expected to cost half the price of an equivalent-sized Gas Turbine generator, U.S. Megawatts expects to attract the interest of, and sign purchase orders with, the major Electric Utility, Natural Gas utility and QF decision-makers who can make more money selling electricity from a $50-million 100-MW Linear Engine Generator facility compared to a $100-million 100-MW Gas Turbine Generator facility.

Linear Engines can burn natural gas to heat large volumes (1000s of CFM) of high-pressure (1500 psi) compressed air, which pushes wide-bore (12-24  inch diameter)  Linear Pistons with long strokes (5-10 feet), at high stroke-per-minute rates (600 spm), producing the horsepower to turn 1-100-MW generators – and they can do all this at half the cost of competing, complicated Gas Turbine engine generators.

Linear Engine-based MW-sized U.S. Megawatts Generators can be sold to and installed in:

(1)    New 100+MW power plants,

(2)    Old Coal-fueled power plants that want to convert to Natural Gas, and

Local Businesses connected to a Natural Gas Meter, who want to save money on their largest expense (Energy) by generating their own power, on-site, with a     1-10-MW U.S. Megawatts Generator     (at a cost-per-kWh less than they currently pay the local Utility).

Efficient engines ever tested, it only has the potential to become a new technology standard for 21st Century natural gas-fueled engines and electric generators:  because it is smaller in size and lower in cost than competing Gas Turbine and Recip Engines.

  • The U.S. Megawatts Generator is less than half the size of an equivalent MW-output Gas Turbine
  • The U.S. Megawatts Generator is less than half the cost of an equivalent MW-output Gas Turbine

And therein lies the billion-dollar market opportunity for Linear Engine-based MW-sized U.S. Megawatts Generators – a better product at a lower price than its Gas Turbine competitors.

Independent Power Producers


U.S. Megawatts was formed to satisfy the strong and growing market demand in the USA by local Electric Utilities, Independent Power Producers (Non-Utility Generators) and cogeneration-type Qualifying Facilities (QFs) to transition their power generation from the old business model of high-cost, highly-regulated Centralized Coal and Nuclear fueled Power Plants (that deliver thousands of megawatts of electricity over hundreds of miles of expensive long-distance transmission lines) to the new Distributed Energy business model of installing smaller, 1-100-MW sized natural gas-fueled electric generators closer to end-users, at the local electric utility sub-station or neighborhood Distributed Energy Generator site (wherever there is a low-cost natural gas connection to fuel an electric generator).

U.S. Megawatts owns the exclusive North American License in the field of multi-megawatt power generation to build, own, operate, sell, rent and market a much-needed new kind of cleaner, Natural Gas-fueled prime-mover technology:  the Free-Piston Linear Engine (see video at: http://youtu.be/jG3IOGzjDNE ) that offers higher demonstrated energy conversion efficiency for multi-MW power generation than a reciprocating engine or gas turbine-powered electric generator.

Historically, the electric power generating industry used three kinds of of Prime Mover engine-technologies to turn and power their multi-MW electric generators: (1) Coal-fired or Nuclear-heated rotary-vane Steam Turbine Engines, (2) Diesel-fueled Reciprocating (12-16 cylinder Internal Combustion) Engines, and (3) Natural Gas-fueled rotary Gas Turbine Engines.

With the Fukushima Nuclear disaster in Japan and stricter new EPA regulations (“Utility MACT” and CSAPR “Cross State Air Pollution Rules”) requiring stringent pollution abatement upgrades, it has now become too costly, financially and politically, for Nuclear-powered Steam Turbines, Coal-fired Steam Turbines and some Diesel-fueled Recip Engine-powered generators to continue in operation in the USA (especially when compared to the financial and environmental benefits of switching to cleaner, lower cost Natural Gas as the fuel to replace vilified Coal and Diesel).

The thousands of MWs of Coal-fired electric power being de-commissioned around the USA over the next five years will have to be replaced with equally reliable power generators that can deliver enough hot Summer air conditioning power to meet local demand without brownouts.  Considering the high cost of Diesel fuel and Coal to generate a MW of power today,  it is becoming increasingly obvious to decision-makers in the electric power industry that Natural Gas should be America’s fuel of choice (generating electricity more cleanly, and even at a lower cost than, coal-fired electricity).

This transition to Natural Gas-fueled electric generation is confirmed by the growing backlog of orders for high-cost, long lead-time, multi-MW Gas Turbines – which are the only type of multi-MW natural gas-fueled generators currently known to the power industry.

However, Gas Turbine generators are not the best candidates for smaller, neighborhood-based Distributed Power generating facilities.  Besides being expensive to fabricate and install (costing more than $1-million per MW of output capacity due to the complexity of their  turbine-blades that are costly to manufacture and maintain), Gas Turbines are too loud to operate in many commercial zones – effectively confirming that Gas Turbine-powered Electric Generators are not going to meet the industry-need for smaller, quieter natural gas-fueled Distributed Power Generators needed by the industry.

U.S. Megawatts’ linear engine-powered generators will offer effective noise-suppression in a smaller, lower-cost package.  For comparison sake, the following chart details the size of different components of the Linear Engine Generator to generate a desired net power output (of 20-MW, 35-MW and 50-MW)  from a given air compressor input flow-rate (of 6,000,   10,000 and 15,000 cfm) with an input pressure of 1,500 psi (which is standard in the oil field).

While it is the cfm-flow-rate and psi-pressure that defines the available energy for the Linear Engine to extract, the diameter of the pistons and length of the cylinder strokes are defined by the need to keep the strokes-per-minute value under 600spm in consideration of the size and weight of the corresponding 16-22 inch diameter pistons and 7.2-9.5 foot long cylinder stroke lengths to generate 20-MW, 35-MW and 50-MW of net electrical power:


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