Its pretty much a fallacy. ANY IC engine is going to produce some NOx
type compounds, and these are some of the worst smog generators. S0x is
worse, but suphur can be removed from most fuels reasonably easily. (of
course those who use sulphuirtc acid to remove dyes from 'red' diesel,
and sell it on un refined to cheapskate Volvo owners are a different case)
If you go for lower temp combustion, you end up with lower cylinder
pressures and less overall efficiency, so although NOx goes down, CO2
goes up..well you can turbo charge to get round THAT I suppose, but even
so the efficiency is not all that good.
If you want a really clean burning engine, run it off liquid hydrogen
and liquid oxygen...and pray it doesn't go BOOM. :)
Of course the pollution generated in MAKING these is probably far
higher, but heck, you can put your power plants in Brazil, so LA stays
clean at least, and who cares about Brazilians anyway. :-)
"Indy Cars" use methanol as a fuel. When it comes to racing there are
also issues surrounding the safety of the fuel and the risk of
spillages. The engines of such cars are specifically designed for the
fuel in question and only intended to last to the end of the race. Which
in the case of drag racing is measured in seconds.
A top fuel dragster will, if lucky, do about 5 x 5 second burns. Many
fail spectacularly doing it. Most racers will only cane the engine
enough to beat the other guy.
A normal racing engine - F1 say - will usually do 5-10 races before
complete rebuild. Needless to say top teams with money to burn and
drivers who just want to win will run the revs up higher, and break them
quicker, so they usually get rebuilt pretty much every race.
Its not unlkown to see driver X with underfinanced team Y suddenly, at
about tehtime he wants to ghet into a decent team, suddenly put on a
performance that is way above what he normally delivers. The
commentators say 'why can't he do that all teh time, he ust havbe been
threatend with teh sack and wants to keep his place' Enlightened team
owners to whom he has already had a chat will know that he has just
RISKED the sack by taking his worn out old engine up to the redline to
show what he COULD do in a decent car...:-)
firstname.lastname@example.org (Michael McNeil) wrote in message
Illuminating details Michael. One more detail I could add is that at
least one of the earliest horseles carriages had spring-return
steering, such that the straightetning up of the wheels was effected
only by a spring. Needless to say it failed to straighten up now and
The nearest to this would be a diesel-electric locomotive,
but they use conventional diesel engines to drive generators.
The most common usage of gas turbines is aircraft, with some
usage in ship propulsion.
It means that the output of the engine changes after the throttle
has been changed. Which isn't the kind of behaviour people expect
from a car engine. (Possibly even those familiar with piloting
jet aircraft would have problems driving a car which behaved in
The latter. It can take up to 20 seconds for a turbofan to reach full power.
This would not be good for overtaking. However, this is somewhat misleading.
The lag can be countered for by careful design of the transmission. This is
because it is the acceleration of the components that takes time, not the
variation in input power, which can be changed rapidly by varying fuel flow.
Power can be varied much more rapidly if the engine is allowed to rotate at
constant speed. This enables their use in helicopters and provides much
better control in turboprops, where power can be almost instananeously
altered with the use of variable pitch (constant speed) propellors.
In a land vehicle application, the use of a variable speed transmission
would have a similar effect. Instant acceleration would consist of rapidly
increasing the fuel flow and adjusting the transmission to keep the engine
at the constant speed (coordinated by a FADEC). Response to the throttle
would be determined by the transmission's ability to immediately adjust
ratio, not the response of the engine.
Obviously, total acceleration is limited by the total fuel flow that can be
pumped into the engine. If this is exceeded (but ratio adjusted regardless),
the engine will slow down. This could be beneficial, though. There would be
some ability to get extra "overtaking" boost by accepting a certain LP shaft
reduction. This might allow a smaller engine for the same application.
I think the real problems with turbine land vehicles would be cost,
gyroscopic effects and safety considerations from the high energy contained
in the rotating engine structure (uncontained engine failures, crash
On Sat, 23 Aug 2003 23:33:39 +0100, Mark Evans wrote:
Doesn't seem to worry buses in China, they have huge tanks on the
roof. This water is required for the brakes, they fill the tanks
before starting the longer decents on the road between Lijiang and
Chengdu. How much water do you need to inject? Could it be emulsified
into the fuel, perhaps at the pump? Or even simply added in the
correct proportion at the pump into the fuel. The tank then having a
lowest point take off for the water and a higher one for the fuel.
Dave. pam is missing e-mail
Years ago there was a gizmo you could buy (often offered in E&M)
that fed steam into the air intake of the carb. It was a water
bottle feeding down to a copper coil wound around the exhaust
pipe, and then up to the air cleaner.
Well any diesel I have driven, including BMW's finest., all felt like
they had to be rowed along on the gearbox. The low end torque that is
talked about never manifested itself in my presence.
What I really don't understand is why peoplr who buy diesel engined
cars then procedd to drive the sh-one-t out of them. What are they
trying to prove ?
And as for reliability. Diesel engines in boats were ultra-reliable
until they started fitting turbo-chargers and letting them rev higher.
Reliability went out the window, and if you really need an emetic try
reading a repair estimate for a turbo charged Volvo diesel boat
Paul Mc Cann
I drive a diesel Freelander which is really a tractor with a bit of
fancy bodywork bolted on :)
A few weeks back I got to hire a Mondeo TDCi for a couple of days
whilst my Freelander was in for servicing. I didn't check what was
under the bonnet of the TDCi, but the thing went like lightning
(comparitively to the Freelander) when I hoofed it. I thought "hell,
these petrol engines sure put the diesel to shame!".
When I got home I got the user manual out. This thing I was giving
credit to was a 2L diesel. Went like a steam train on steroids when
you put the hammer down, plenty of grunt and really smooth.
The new TD4 Freelander is a lot better as well.
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