Efficiency of Engines

http://en.wikipedia.org/wiki/Internal_combustion_engine

The fuels have different properties, requiring a different design of engine in which to work.

hai i am kaviarasan doing my final mec....

petrol`s calorific value is greater than diesel.. so like comressing the diesel in diesel engine we cant able to compress the petrol and spray it...the petrol will ignites quickly....

in petrol engine, if we use diesel we cant able to achive such a spark plug to ignite diesel.... the spark from spark plug is very small.... for mare queries mail me at "er.kaviarasan@yahoo.com"

hi, i accept your all points dear, but what do u think of engines, is it rely particularly on any area or confronted to some particular application ...no, your all quotes supporting your points are all good! but im thinking of building an engine which can sustain any kind of fuel and works according to that ... why shoudn't we think in that way definitily there will be a possibility for that what do u say

There has been one around for some time it is called a steam engine!!

How right you are Garth, by the way, the word Garth is quite common round about where I live, we have an area called Garth, I went to a school called Garth School, Getting back to the steam engine, my father drove one for many years, he carried flour to all the bakers, the sacks in those days weighed 2 cwt.(224 lbs)and had to be carried upstairs above the bakery, everything worked by gravity from there! He would have to stop at the steep hills, get under the engine and move the gear by hand to the low gear, then chug up the hill, stop, and change to the original gear again, I seem to recall he carried ten, or twelve tons on the wagon, with a further load on the trailer! He also told me he once had to go to Foden's the traction engine makers in Sandbach Cheshire, to take delivery of a brand new wagon, and drive it home, a distance of approx. 90 miles. The steam engine is also more efficient than the internal combustion engine, returning something like 28% from memory.

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There is difference between ignition point of petrol and diesel.

please visit howstuffworks.com and automobile section of it.

I think it will help you..

Diesel engines work at a higher heat for ignition, that is the reason for having a high ratio of cylider pressure, i.e. a normal diesel works on a 19 to 1 cylinder pressure in order to generate more heat in the air it compresses, this temperature then ignites the diesel vapour, the petrol engine has a lower ratio, say 10 to 1, the fuel is sprayed or injected, or metered thro' the carburretor, then at the precise moment a spark occurs, which ignites the fuel.there are also other considerations such as the diesel will affect some of the componets used in the system such as seals etc:but the main consideration is that if petrol is sprayed into the heat generated by a diesel cylinder, it usually ends in a very expensive repair job.this does occur on a regular basis on the garage forecourt, which is why, I can never work out how, the designers have not worked out how to design a fuel orifice in the tank, that will not accept a petrol nozzle.

For short, diesel fuel is not ignited through sparks but through compression. For this reason, fuel injectors are different in the two types of ICEs (internal combustion engines), compression rate is different (much higher in diesel) and diesel engines do not have induction coil (or electronic ignition block) and plugs.

A gas engine will simply not work with diesel fuel and putting gas into a diesel engine might be extremely dangerous.

As mentioned before, all these are coming from the difference in the two fuels properties, mainly related to vaporization and ignition. To have a better grip of the concept, take a small quantity of each fuel and try to ignite them in free air with a torch. Gas will ignite instantly while diesel fuel will simply not burn. That's why storing diesel fuel is much safer that storing gas (in your garage, for instance)!

In terms of efficiency, diesel engines are burning about 40% less fuel (by volume) to do the same work. So diesel engines are more efficient than gas engines and for this reason are almost exclusively used for heavy trucks and tanks. A German engineer even proved that a diesel engine is better for small aircrafts and helicopters (with modified gearbox) as it has to lift less fuel. Another generic difference is in torque and rpm: diesel engines develop more torque and less rpm than the gas counterpart.

Another important application for diesel engines is backup generators. They have the amazing property of easily starting after one year or more of not being used.

Sometimes, in wintertime, you might have seen truck drivers worming the fuel pipe with a flame. That's because diesel fuel, especially if it contains sulfur, becomes less fluid than gas in cold temperatures. Countries with long and heavy winters such as Canada do not use diesel engines on small cars.

"To have a better grip of the concept, take a small quantity of each fuel and try to ignite them in free air with a torch. " NOT Recomended. Dont lite yourself on fire MFR!

Hi guest,

I had a very good professor who said: you'll never learn if you're not curious enough to experiment.

My suggestion was just part of the learning process, not intended to harm our brave asker tu5lahmed. By the nature of his question, I assumed he is a cautious guy. You're right - safety is paramount - but this doesn't mean to shut ourselves in a shell and do nothing at all. You know how saying goes: what you're afraid of will always catch you!

Tu5lahmed: to make our guest happy and you to stay safe, just trust me the experiment goes like I said or watch MythBusters.