Peroxide in gas
- Author: cockatiel (---.dslextreme.com)
- Verified User: b_of_m
- Date Posted: 10-15-08 00:34
http://www.madsci.org/posts/archives/1999-05/927171185.Eg.r.html
1st I’ve heard of it. Supposedly cleaner with better mileage. More power?
_Re: Why does hydrogen peroxide injection reduce emissions in 2 stroke engines
Date: Wed May 19 12:10:34 1999
Posted By: Adrian Popa, Directors Office, Hughes Research Laboratories
Area of science: Engineering
ID: 926974436.Eg Message:
Greetings:
I have read the Mercury Marine web pages at the following URL and I could
not find any reference to hydrogen peroxide injection into their engines so
I’ll have to make an educated guess to answer your question:
http://www.mercurymarine.com/mercuryhome/
Combustion, or burning, is a rapid, self-sustaining chemical reaction that
releases a significant amount of heat. Examples of common combustion
processes are burning candles, forest fires, log fires, the burning of
natural gas in home furnaces, and the burning of gasoline in internal
combustion engines. For combustion to occur, three things must normally be
present: a fuel, an oxidizer, and an ignition stimulus. (An exception is
hypergolic combustion used in space vehicles, in which a fuel and an
oxidizer spontaneously react on contact without the need for an ignition
stimulus.)
Fuels can be solid, liquid, or gas. Examples of solid fuels include wood,
and coal. Liquid fuels include gasoline and kerosene. Propane and hydrogen
are examples of gaseous fuels.
Oxidizers can also be solid (such as ammonium perchlorate, which is used in
space shuttle booster rockets), liquid (such as hydrogen peroxide), or
gaseous (such as oxygen). Air, which contains 21% oxygen, is a particularly
common oxidizer.
Electrical sparks or glow plugs are examples of an ignition stimulus.
Let’s review the operation of typical 4 stroke and 2 stroke internal
combustion engines:
Stroke 1: the oxidizer (air) and fuel (gasoline) are drawn into (or
injected into) a cylinder during a piston down stroke.
Stroke 2: The fuel/oxidizer mixture is compressed during a piston up stroke
Stroke 3 : The spark plug ignites the fuel/oxidizer mixture driving the
piston down in a power stroke.
Stroke 4: The rising piston drives the combustion by products completely
out of the cylinder during an upstroke
The advantages of the 4 stroke engine are that the intake, compression,
ignition/power and exhaust cycles are separate events that are efficiently
completed, each having about 25% of the total time of operation.
The disadvantage is that 2 rotations of the crankshaft are required for
each power stroke. Four stroke engines typically have several cylinders to
enable a smooth running engine, particularly when operated at low
revolutions per minute (RPM).
Small, compact, air cooled internal combustion engines often use a 2 stroke
process.
Stroke 1: On the upstroke a fuel/air mixture is compressed along with some
residue exhaust gas from the previous cycle.
Stroke 2: The spark plug ignites a fuel/air mixture providing a power
stroke which also exhausts the combustion products at the end of the
stroke.
The advantage of the 2 stroke engine is that a power stroke occurs for
every rotation of the crank shaft.
The disadvantages are incomplete fuel/oxidizer intake and combustion
exhaust processes due to the short time (a few % of the total operation)
available to perform these functions.
To make 2 cycle engines more efficient with less pollutants in the exhaust,
an optimum fuel/air mixture can be quickly inserted into the cylinder with
a high pressure fuel injector. This has improved 2 stroke engine power and
efficiency.
However, because air is composed of 78% nitrogen and only 21% oxygen (the
oxidizer) the fuel/oxidizer mixture is still far from optimum,
particularly with the 78% of unwanted, pollution causing nitrogen in air.
By injecting an efficient, non polluting oxidizer, such as hydrogen
peroxide (H2O2), into the cylinder along with the fuel/air mixture,
additional oxygen is made available for combustion process and water (H2O
as steam) is a major by product from the added process. The steam can also
remove heat from the cylinder reducing the need for cooling of the engine.
Hydrogen peroxide could improve the operation of 4 stroke engines but the
gain is not nearly as great as would be obtained with 2 stroke engines.
Here in California many industries cannot not use air in there combustion
processes and liquid or gaseous oxygen are used in place of air to greatly
reduce air polution. However, these are typically fixed sites and not
vehicles. Hydrogen fueled vehicles are also being tested in many states.
Hydrogen peroxide (H2O2) is an interesting chemical that is now being used
to clean up a number of polluting processes here on planet earth. You can
read about some of these applications at the following web site:
http://www.h2o2.com
Best regards, Your Mad Scientist
Adrian Popa_
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