Bigger Power with 2-Strokes

In our last publication, we touched a bit on 4-strokecylinder head.
dieselengine. Today, let's touch on 2-strokes.From Bottom Dead Center (BDC), the piston, full of
What is a 2-stroke diesel engine?freshair, moves up the cylinder liner until it covers up
As the name suggests, these engines work onthe airintake port. The air intake process stops.
reciprocatingactions of pistons. One stroke meansThe piston moves further up. It then covers up the
one linear motion of thepiston in one direction. Whenexhaustport on the cylinder liner. The exhaust
the piston moves in the oppositedirection, that isprocess stops.
counted as another stroke.The piston moves further up. The air inside the
For a 2-stroke engine, the piston has to move up,combustionspace is compressed and becomes hot.
and then downto complete one cycle of the engine.The piston has nearlyreached Top Dead Center at
In those 2 strokes of thepiston, the crankshaft willthis point.
have turned 1 revolution.Highly atomized fuel is then injected into the
The 2 strokes of the piston is to complete 4 stagescombustionspace. The fuel burns rapidly causing an
of thecombustion cycle - air intake, compression,explosion insidethe combustion space. The explosion
combustion andexhaust. As you might have known,causes a tremendousrise in pressure and the piston is
in order for a fire (orexplosion) to occur to powerpushed down towards BDC.
the engine, we need a fuel, aheat source, andAs the piston moves down, the exhaust ports
oxygen coming together at the same time.uncover about
Remember how the crankshaft and the piston50 degrees from BDC. Exhaust gases are thus led
moves in a cylinder?out from thecylinder. The pressure inside the cylinder
The reciprocating movement of the piston isdrops immediately.
converted to rotarymotion by means of aThe piston moves further down. At 35 degrees from
crankshaft. The piston reciprocates betweenBDC, ituncovers the air intake port. Fresh air is then
Top Dead Center and Bottom Dead Center inside theled into thecylinder.
cylinder liner.The piston then reaches BDC. Because of the
One of the most prominent feature of a 2-strokemomentumcreated from the force of the explosion,
engine is thepresence of air intake ports on thethe piston reversesin direction and moves upwards
cylinder liner that willenable fresh air to be led in fortowards Top Dead Center (TDC).
combustion.The process then repeats itself.
These air inlet ports are cut into the cylinder linerIn some designs, the exhaust gases are removed
somewhereat the lower end of the latter. In a typicalthrough anexhaust valve, located at the cylinder head
design, the airinlet port are located about 35 degreesand very similarto the 4-stroke engines. This type of
from the Bottom Deadscavenging is calleduniflow scavenging. The timing of
Center (BDC).the valve opening andclosing will be controlled by a
In many designs, the fresh air that is introduced intocamshaft, push rods, rockerarms or other similar
thecylinder is also used to drive out the spentdevices.
exhaust gasesinside it. Many designs make use ofWell folks, why do we want to squeeze all the
scavenging air fans likeelectric blowers orstrokes into
turbochargers to slightly pressurize theintake air2 cycles? That could be discussed further...
before the latter is introduced into the cylinder.Make "hard-to-find" Tools "easy-to-find". You can only
In order to allow the exhaust gases to be expelledProduce
from thecylinder, exhaust ports are often cut intoYOUR BEST with THE BEST!" Earn praises for a job
the cylinder justlike the air intake ports. A typicalwell done,only with the PROPER TOOLS! Locate
design will have theexhaust port located about 50Hard-to-Find Tools for yourgarage and workshop.
degrees from Bottom Dead Center.Good for Cars, Trucks, Cycles, Boats, and
So, let's describe our engine stages at thePlanes.
combustion spacebetween the piston top and the