The internal combustion
engine is an engine in which the combustion, or rapid oxidation, of
gas and air occurs in a confined space called a combustion chamber.
This exothermic reaction of a fuel with an oxidizer creates gases of
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 pressure, further causing movement of the piston inside the
cylinder. For example by acting on pistons, rotors, or even by
pressing on and moving the entire engine itself.
This contrasts with external combustion engines, such as steam
engines and Stirling engines, which use an external combustion
chamber to heat a separate working fluid, which then in turn does
work, for example by moving a piston.
The term Internal Combustion Engine (ICE) is almost always used to
refer specifically to reciprocating engines, Wankel engines and
similar designs in which combustion is intermittent.
Gasoline Ignition Process
Electrical/Gasoline-type ignition
systems (that can also run on other fuels as previously mentioned)
generally rely on a combination of a lead-acid battery and an
induction coil to provide a high voltage electrical spark to ignite
the air-fuel mix in the engine's cylinders. This battery can be
recharged during operation using an electricity-generating device,
such as an alternator or generator driven by the engine. Gasoline
engines take in a mixture of air and gasoline and compress to less
than 170 psi and use a spark plug to ignite the mixture when it is
compressed by the piston head in each cylinder.
Two-stroke
Engines based on the two-stroke cycle
use two strokes (one up, one down) for every power stroke. Since
there are no dedicated intake or exhaust strokes, alternative
methods must be used to scavenge the cylinders. The most common
method in spark-ignition two-strokes is to use the downward motion
of the piston to pressurize fresh charge in the crankcase, which is
then blown through the cylinder through ports in the cylinder walls.
Spark-ignition two-strokes are small and light (for their power
output), and mechanically very simple; they are also generally less
efficient and more polluting than their four-stroke counterparts.
However in single cylinder small motor applications cc for cc, a
two-stroke engine produces much more power than equivalent 4 strokes
due to the enormous advantage of having 1 power stroke for every 360
degrees of crankshaft rotation (compared to 720 degrees in a 4
stroke motor).
Two-stroke engines have been less fuel-efficient than other types of
engines because unspent fuel being sprayed into the combustion
chamber can sometimes escape out of the exhaust duct with the
previously spent fuel. Without special exhaust processing, this can
produce high pollution levels. Whilst two-stroke motors remain
popular in Europe and Asia, they are penalised in some American
markets such as California for this reason.
Research continues into improving many aspects of two-stroke motors,
including direct fuel injection amongst other things. Initial
results have produced motors that are much cleaner burning than
their traditional counterparts.
Two-stroke engines are widely used in snowmobiles, lawnmowers,
weed-whackers, chain saws, jet skis, mopeds, outboard motors and
many motorcycles.
The largest compression-ignition engines are two-strokes, and are
used in some locomotives and large ships. These engines use forced
induction to scavenge the cylinders. An example of this type of
motor is the Wartsila-Sulzer turbocharged 2 stroke diesel as used in
large container ships. It is the most efficient and powerful engine
in the world, with over 50% thermal efficiency for comparison the
most efficient small 4 stroke motors are around 43.0% thermal
efficiency (SAE 900648), and size is an advantage for efficiency due
to the increase in the ratio of volume to area.
Diesel Engine
Ignition Process
Compression ignition systems, such as
the diesel engine and HCCI engines, rely solely on heat and pressure
created by the engine in its compression process for ignition.
Compression that occurs is usually more than three times higher than
a gasoline engine. Diesel engines will take in air only, and shortly
before peak compression, a small quantity of diesel fuel is sprayed
into the cylinder via a fuel injector that allows the fuel to
instantly ignite. HCCI type engines will take in both air and fuel
but will continue to rely on an unaided auto-combustion process due
to higher pressures and heat. This is also why diesel and HCCI
engines are also more susceptible to cold starting issues though
they will run just as well in cold weather once started. Most
diesels also have battery and charging systems however this system
is secondary and is added by manufacturers as luxury for ease of
starting, turning fuel on and off which can also be done via a
switch or mechanical apparatus, and for running auxiliary electrical
components and accessories. Most old engines, however, rely on
electrical systems that also control the combustion process to
increase efficiency and reduce emissions.
History
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.
1509: Leonardo da Vinci described a compression-less engine.
1673: Christian Huygens described a compression-less engine.
17th century: English inventor Sir Samuel Morland used
gunpowder to drive water pumps.
1780's: Alessandro Volta built a toy electric pistol ([5]) in
which an electric spark exploded a mixture of air and hydrogen,
firing a cork from the end of the gun.
1794: Robert Street built a compression-less engine whose
principle of operation would dominate for nearly a century.
1806: Swiss engineer François Isaac de Rivaz built an
internal combustion engine powered by a mixture of hydrogen and
oxygen.
1823: Samuel Brown patented the first internal combustion
engine to be applied industrially. It was compression-less and based
on what Hardenberg calls the "Leonardo cycle," which, as this name
implies, was already out of date at that time.
1824: French physicist Sadi Carnot established the
thermodynamic theory of idealized heat engines. This scientifically
established the need for compression to increase the difference
between the upper and lower working temperatures.
1826 April 1: The American Samuel Morey received a patent for
a compression-less "Gas Or Vapor Engine".
1838: a patent was granted to William Barnet (English). This
was the first recorded suggestion of in-cylinder compression. 1854: The Italians Eugenio
Barsanti and Felice Matteucci patented the first working efficient
internal combustion engine in London (pt. Num. 1072) but did not go
into production with it. It was similar in concept to the successful
Otto Langen indirect engine, but not so well worked out in detail.
1860: Jean Joseph Etienne Lenoir (1822 - 1900) produced a
gas-fired internal combustion engine closely similar in appearance
to a horizontal double-acting steam beam engine, with cylinders,
pistons, connecting rods, and flywheel in which the gas essentially
took the place of the steam. This was the first internal combustion
engine to be produced in numbers. 1862: Nikolaus Otto designed an
indirect-acting free-piston compression-less engine whose greater
efficiency won the support of Langen and then most of the market,
which at that time, was mostly for small stationary engines fuelled
by lighting gas. 1870: In Vienna Siegfried Marcus put the first mobile
gasoline engine on a handcart.
1876: Nikolaus Otto working with Gottlieb Daimler and Wilhelm
Maybach developed a practical four-stroke cycle (Otto cycle) engine.
The German courts, however, did not hold his patent to cover all
in-cylinder compression engines or even the four stroke cycle, and
after this decision in-cylinder compression became universal.
Karl Benz1879: Karl Benz, working independently, was granted a
patent for his internal combustion engine, a reliable two-stroke gas
engine, based on Nikolaus Otto's design of the four-stroke engine.
Later Benz designed and built his own four-stroke engine that was
used in his automobiles, which became the first automobiles in
production.
1882: James Atkinson invented the Atkinson cycle engine.
Atkinson’s engine had one power phase per revolution together with
different intake and expansion volumes making it more efficient than
the Otto cycle.
1891 - Herbert Akroyd Stuart built his oil engine, leasing
rights to Hornsby of England to build them. They build the first
cold start, compression ignition engines. In 1892, they installed
the first ones in a water pumping station. An experimental
higher-pressure version produced self-sustaining ignition through
compression alone in the same year.
1892: Rudolf Diesel developed his Carnot heat engine type
motor burning powdered coal dust.
1893 February 23: Rudolf Diesel received a patent for the
diesel engine.
1896: Karl Benz invented the boxer engine, also known as the
horizontally opposed engine, in which the corresponding pistons
reach top dead centre at the same time, thus balancing each other in
momentum.
1900: Rudolf Diesel demonstrated the diesel engine in the
1900 Exposition Universelle (World's Fair) using peanut oil (see
bio-diesel).
1900: Wilhelm Maybach designed an engine built at Daimler
Motoren Gesellschaft—following the specifications of Emil Jellinek—who
required the engine to be named Daimler-Mercedes after his daughter.
In 1902 automobiles with that engine were put into production by DMG.
