Diesel for Diamond DA40?

"karl gruber" wrote

FADEC won't make an engine run more efficiently. It will make it easier to
manage.

In a way that is true, but at the same time it is as false as can be.

A properly leaned engine at cruise, with well matched injectors, will have
all of the cylinders humming happily along at the most efficient setting,
and lowest fuel flow. FADEC can not improve on that much, if any.

But, and it is a big but, think of the settings we run on takeoff, and
landing (in case you have to do a go-around) and of the time you are at
idle, or low power on the ground. You are running much richer than need be,
and not as lean as FADEC would have things set. On the average, us setting
the mixture is wasting fuel, and is inefficient as compared to FADEC. FADEC
will reset the mixture many times per second; as often as is needed. That
is something we can never begin to think about doing.
--
Jim in NC

But, and it is a big but, think of the settings we run on takeoff, and
landing (in case you have to do a go-around) and of the time you are at
idle, or low power on the ground.

Most of the time will be spent at cruise (unless you are in the
pattern), so I would not expect that to be all that much.

Jose
--
There are two kinds of people in the world. Those that just want to
know what button to push, and those that want to know what happens when
they push the button.
for Email, make the obvious change in the address.

Jose wrote:
But, and it is a big but, think of the settings we run on takeoff, and
landing (in case you have to do a go-around) and of the time you are
at idle, or low power on the ground.


Most of the time will be spent at cruise (unless you are in the
pattern), so I would not expect that to be all that much.



A FADEC on a plane like a 182 will save on average 2 GPH, that's huge.
So saying a FADEC in and of itself is not what makes it more efficient
is theoretically true but it is practically true. A human will never be
able to operate the engine at its most efficient, for a computer it is
simple.

FADEC is much more than just controlling mixture. that system is measuring,
monitoring and governing a whole lot of parameters. compared to a human
operating a few levers, FADEC can set all these parameters in a way so the
engine/propeller-combination operates much closer to its optimum.

also, today's engines can only be that economic because of the electronic
system. as an example, fuel injection varies in injection time and the
amount of fuel injected, depending on RPMs, power setting, flow of the mass
of air through the manifold (not just the air pressure in there) and
probably a few more. you cannot achieve this by mechanical or even maunual
solutions.



uli






Morgans wrote:


A properly leaned engine at cruise, with well matched injectors, will have
all of the cylinders humming happily along at the most efficient setting,
and lowest fuel flow. FADEC can not improve on that much, if any.

But, and it is a big but, think of the settings we run on takeoff, and
landing (in case you have to do a go-around) and of the time you are at
idle, or low power on the ground. You are running much richer than need
be,
and not as lean as FADEC would have things set. On the average, us
setting
the mixture is wasting fuel, and is inefficient as compared to FADEC.
FADEC
will reset the mixture many times per second; as often as is needed. That
is something we can never begin to think about doing.

"Uli" wrote

FADEC is much more than just controlling mixture. that system is
measuring,
monitoring and governing a whole lot of parameters. compared to a human
operating a few levers, FADEC can set all these parameters in a way so the
engine/propeller-combination operates much closer to its optimum.

also, today's engines can only be that economic because of the electronic
system. as an example, fuel injection varies in injection time and the
amount of fuel injected, depending on RPMs, power setting, flow of the
mass
of air through the manifold (not just the air pressure in there) and
probably a few more. you cannot achieve this by mechanical or even maunual
solutions.

Of course it does much more, but the mixture is a big part of the equation.
One thing you missed mentioning is the timing, on some systems.
--
Jim in NC