Diff. between CFI and EFI?
Prakash Jayaraman
Hi
My 1988.5 Escort LX has "Central Fuel Injection" mechanism
as per the vehicle identification number and its meaning from
the Chilton's manual. (eventhough the outer cover for the
fuel injection mechanism under the hood says, "EFI" in big
letters..).
What is the difference between central and electronic
fuel injection systems? The newer ford escorts have SEFI engines,
how is SEFI more advanced than EFI?
Also, what does a 1988.5 Escort have/give that a 1988 Escort
doesn't? (or vice versa?)
I always wonder why an LX model doesn't have a cupholder!
Where did you get one to fit your car?
Thanks for your help.
regards
Prakash
Nielsen_Philip
Paul Resch (pcr...@ix.netcom.com) wrote:
: CFI is a type of EFI. EFI would include port, direct, throttle body
: and whatever CFI is.
CFI is "Central Fuel Injection," Ford's version of Throttle Body. Single
injector sits above the throttle plate.
EFI in Ford parlance is port. One injector per cylinder at the intake valve.
Phil (got both kinds)
Paul Resch
CFI is a type of EFI. EFI would include port, direct, throttle body
and whatever CFI is.
In the same way all gas and diesel engines are both Otto cycle.
Paul
In <31FCF807...@cisco.com> Prakash Jayaraman <pjay...@cisco.com>
writes:
George Jefferson
:
:In the same way all gas and diesel engines are both Otto cycle.
sorry, diesel engines use a .... diesel cycle.
Frank Mallory
G>:In the same way all gas and diesel engines are both Otto cycle.
G>sorry, diesel engines use a .... diesel cycle.
I think you are right, but I don't really understand why. Modern Diesel engines
are known as "compression ignition" engines, so it appears that the ignition is
the principal difference between it and "spark ignition" engines.
However, Judge in _Modern Petrol Engines_ classifies Otto cycle engines as
"constant volume" designs; whereas Diesel cycle engines use a "constant
pressure" design (there is a third design, called the Carnot cycle). Evidently,
the fact that gas engines require a throttle, whereas many Diesel engines run
unthrottled, has some influence on this.
Judge states that the 4-cycle engine was actually originated in 1862 by a
Frenchman, Alfonse Beau de Rochas. Dr. N. A. Otto didn't come out with his "new
Otto engine" until 1876. de Rochas didn't actually build any engines; if he
had, we would probably be speaking of the "de Rochas cycle" engine.
David Heisterberg
Frank Mallory (Frank_...@srs.blkcat.com) wrote:
: However, Judge in _Modern Petrol Engines_ classifies Otto cycle engines as
: "constant volume" designs; whereas Diesel cycle engines use a "constant
: pressure" design (there is a third design, called the Carnot cycle). Evidently,
: the fact that gas engines require a throttle, whereas many Diesel engines run
: unthrottled, has some influence on this.
No, it just has to do with the conditions under which combustion occurs.
For gasoline engines the majority of the combustion takes place within
about, oh, +/-10 degrees of TDC. Over that range the chamber volume is
pretty much constant. Diesels inject fuel over a wide range of crank
rotation and hence chamber volume. And it's done such a way that
cylinder pressure stays roughly constant. In that respect diesels are
more like steam engines.
Dave Heisterberg
Martyn Uttley
Frank_...@srs.blkcat.com (Frank Mallory) wrote:
>However, Judge in _Modern Petrol Engines_ classifies Otto cycle engines >as "constant volume" designs; whereas Diesel cycle engines=
use a >"constant pressure" design (there is a third design, called the Carnot >cycle). Evidently, the fact that gas engines require=
a throttle, whereas >many Diesel engines run unthrottled, has some influence on this.
>
You're right. Actually the speed of combustion plays an important part.
In a "true" constant volume cycle all combustion should take place at top
dead centre. A constant pressure cycle requires combustion during
expansion. Both cycles require no heat loss or gain.
In fact the constant volume cycle is a more efficient cycle than a
constant pressure cycle (other factors being equal). It is the other
inefficiencies (throttling as you mention being one of them) which make
the diesel engine more efficient in the end.
--
Martyn C. Uttley "nothing succeeds like excess" - Wilde
Hong Kong (GMT + 8hrs)
e-mail "mut...@hk.super.net"
Herbert Childs
geo...@mech.seas.upenn.edu ( George Jefferson ) wrote:
>:
>:In the same way all gas and diesel engines are both Otto cycle.
>sorry, diesel engines use a .... diesel cycle.
FYI, any internal combustion reciprocating engine operates on the Otto
cycle . It refers to the four cycles required to produce power. Those
are intake, compression, power and exhaust. Subdivisions include the
two stroke cycle in whick the Otto cycle is completed every revolution
of the crankshaft and the four stroke cycle in which the Otto cycle is
completed every other revolution of the crankshaft.
The Diesel engine is named after Dr. Rudolf Diesel for his process of
using very high compression ratios which provide high enough
temperatures to provide ignition as the fuel is injected directly into
the cylinder to start the power stroke. Hence, the term "compression
ignition". No intake air throttling is required as the speed and
power production are controlled by the quantity and duration of fuel
delivery. That is the main reason a Diesel engine is remarkably more
efficient than a spark ignition engine.
A spark ignition engine engine operates essentially the same with the
exceprion of typically much lower compression ratios. A mixture of
fuel and air is drawn into the cylinder through throttling device
which controls the engines speed and power production. Ignition of
the fuel/air charge is provided by an electrical spark. The limited
ability to control the combustible fuel/air ratio without resulting in
misfire or detonation results in reduced efficiency compared to the
Diesel engine.
Now, to get back to the original post, CFI indicates the injector(s)
typically located above the throttl plate. All gasoline fuel
injection is "EFI" which only means "Electronic Fuel Injection". CFI
is only a variation as is MPI (multi-port injection or SEFI which is
Sequential Electronic Fuel Injection in which the injector are timed
with the cylinder much as a spark plug would be.
Herbert Childs
Conyers, GA
hch...@atl.mindspring.com
JBlessing
In article <4tlql7$v...@netnews.upenn.edu>, geo...@mech.seas.upenn.edu
says...
>
>:
>:In the same way all gas and diesel engines are both Otto cycle.
>
>sorry, diesel engines use a .... diesel cycle.
>
>
And of course Mazda makes Rotarys and Miller cycle engines.
--
Jordan Blessing L1 Master Tech