THE SIX-STROKE ENGINES

ABSTARCT
The greatest discovery of mankind is fire. It is from fire we obtain heat energy
which forms the base for all kinds of energy. The modern world thrives on heat energy
used in different forms. Transportation was made easy and comfortable due to the
invention of automobiles which is ultimately powered by heat energy. Every day new
advancement is made in the field of automobiles. Automobile industry is ever-growing
industry and all the new developments are made to increase human comfort and to make
traveling a pleasure. But the conversion rate of energy from one form to another is very
minimal. Almost 95% of the automobiles run on IC engines which are powered by fossil
fuels. As we all know that fossil fuels are getting exhausted. So we must use the gift of
nature (fossil fuels) very efficiently.
The ultimate aim of thermal engineering is to convert the heat energy to
mechanical energy completely, but the maximum energy conversion ratio is limited in
practical implementations. The main application of thermodynamics is in the field of
automobiles. The efficiency of an automobile is around 30%. Since its inception, the
internal combustion (IC) engine has undergone continuous improvements with respect to
efficiency and performance. Future regulatory and environmental requirements are not
only driving still further improvements, but also extending the propulsion system
efficiency through hybridization and potentially obsolescing the IC engine with hydrogen
fuel cells and some new innovative thinking.
This paper describes the potential IC engine improvements to meet tomorrow's
Challenges and the associated business and technical challenges in obtaining these
Challenges. Hence we go in for a new alternative to four stroke engine THE SIX
STROKE ENGINES. The critical role of the IC engine in this portfolio is examined.
FOREWORD
Under the hood of almost all modern automobiles there sits a four-stroke internal
Combustion engine (ICE). Though the efficiency of the design has been improved upon
Significantly in the intervening years, the basic concept is the same today as that used by
The first practical four-stroke engine built in the 1870s. During every cycle in a typical car
Engine, each piston moves up and down twice in the chamber, resulting in four totals
Strokes… one of which is the power stroke that provides the torque to move the vehicle.
But the automotive industry may soon be revolutionized by a new six-stroke design
Which adds a second power stroke, resulting in a much more efficient and less polluting?
Alternative.
In regards to thermodynamic efficiency, the Otto cycle theoretically represents the
Best option for an IC engine cycle. This is due to the fact that the fuel energy is converted
To heat at constant volume when the working fluid is at maximum compression. This
Combustion condition leads to the highest possible peak temperatures, and thus the
Highest possible thermal efficiencies.
In this paper we deal with two new technical modifications in an ordinary fourstroke
Engine which converts it into a six-stroke engine .The six stroke engine captures
The wasted heat from the 4 stroke Otto cycle and creates steam which simultaneously
Cools the engine while providing a free power stroke. This removes the need for a cooling
System making the engine lighter plus giving 40% increased efficiency over the Otto
Cycle.. The engine developed by Bruce Crower has two distinct power strokes, while the
Other one developed by Malcolm Beare is an ordinary four-stroke opposed piston engine,
The top piston controlling the inlet and outlet ports replacing cams and springs which are
Power absorbing components—main piston performing 4 strokes and the top piston
Performing 2 strokes (4+2=6 strokes)
WORKING OF A CONVENTIONAL 4-STROKE ENGINE
The internal combustion engine is an engine in which the combustion of fuel and
An oxidizer (typically air) occurs in a confined space called a combustion chamber. This
Exothermic reaction creates gases at high temperature and pressure, which are permitted
To expand. The defining feature of an internal combustion engine is that useful work is
Performed by the expanding hot gases acting directly to cause movement of solid parts of
The engine, by acting on pistons, rotors, or even by pressing on and moving the entire
Engine itself. The first internal combustion engines did not have compression, but ran on
Air/fuel mixture sucked or blown in during the first part of the intake stroke. The most
Significant distinction between modern internal combustion engines and the early designs
Is the use of compression and in particular of in-cylinder compression?
In a traditional ICE cycle,
 The fuel/air valves open as the piston moves down, which draws air and fuel into
The chamber.
 The valves close as the piston moves back up, putting the air/fuel mixture under
pressure.
 The mixture is then ignited, causing a small explosion which forces the piston
back down, which turns the crank and provides the torque.
 The exhaust valves open as the piston moves back up once again, pushing the byproducts
of the fuel explosion out of the chamber. This leaves the piston back in
its starting position, ready for another cycle.
This process is repeated thousands of times per minute.
Indeed it appears that no fundamental limit exists to achieving high efficiency
from an internal combustion engine cycle. However, many engineering challenges are
involved in approaching ideal Otto cycle performance in real systems, especially where
high compression ratios are utilized. The efficiency of various types of internal
combustion engines vary, but it is lower than electric motor energy efficiency. Most
gasoline fueled internal combustion engines, even when aided with turbochargers and
stock efficiency aids, have a mechanical efficiency of about 20%. The efficiency may be
as high as 37% at the optimum operating point in engines where this is a high priority
such as that of the Prius. Most internal combustion engines waste about 36% of the
energy in gasoline as heat lost to the cooling system and another 38% through the
exhaust. The rest, about 6%, is lost to friction.
BRUCE CROWER’S SIX-STROKE ENGINE
In a normal four stroke engine after the exhaust stroke again the suction stroke
takes place. But the engine has some heat energy left in it which is not utilized. This heat
energy causes the temperature of the walls of the cylinder to rise, which damages the
engine. To cool the engine radiator is used. Radiator absorbs this heat and is disposed as
waste. In six stroke engine we use this heat energy efficiently. The engine harnesses
normally-wasted heat energy by creating steam inside the combustion chamber, and using
it to boost the engine’s power output and also to control its temperature.
The engine runs on normal 4-stroke engine principle followed by a steam-stroke
and another exhaust-stroke. A lot of people don’t know that water expands 1600 times
when it goes from liquid into steam. Sixteen hundred! This is why steam power is so
good.
BEARE DUAL OPPOSED PISTON 6-STROKE ENGINE
The Six stroke Beare Head simply replaces the conventional Four Stroke Engines
Cylinder Head. The manufacturers Four Stroke bottom end remains unchanged. The
Beare Head utilizes an overhead short stroke Crankshaft and Piston arrangement which
opens and closes Inlet and Exhaust Ports leading through the Upper Cylinder Liner. The
Beare Head Technology can be fitted to new production engines or retro-fitted via
aftermarket replacement. The technology combines a four stroke engine bottom end with
an opposed piston in the head working at half the cyclical rate of the bottom piston. The
head piston works in a ported cylinder closely resembling that of a two stroke, thus 4+2=
Six Stroke. The opposing piston acts in unison with auxiliary low pressure reed and
rotary valves, allowing variable compression and a range of tuning options. The engine
demonstrably increases both torque and power output, achieves better fuel economy and
cleaner burning with reduced emissions, and has longer service intervals and
considerably reduced tooling costs when compared with a conventional OHC four-stroke
design.
The top and bottom Crankshaft are connected via a drive chain or toothed belt.
The top Crankshaft and Piston become positive power contributors to the overall power
output, thus increasing the amount of power/torque generated by up to a possible 35%, in
essence, The Beare Dual Opposed Piston Six Stroke Engine results in having Two
Pistons Operating and producing power within each cylinder. The absence of parasitic
CAMS, valves, springs, retainers and guides; all up about 45 dependant and power
absorbing driven components, mean that the Beare Engines bottom end has been freed up
from laboring and is allowed to spin up producing more power.
The additional torque and power further generated by the Top Piston/Crank of the
Beare Cylinder Head is then channeled via the connecting drive chain to the Bottom
Crank. The net result of the Beare Dual Opposed Piston Engine is Tractor type pulling
torque never before realized from a Four Stroke Internal Combustion Engine, the sort of
steady locomotive type performance gained can only be likened to Steam Locomotives or
Diesel Engines.