Re: 1994 - Evinrude Intruder 175hp - FITCH?
the FICHT system was explained to me a while ago, by whom I forget, but this is what I learned. How true it is Im unsure of, but some reading for you none the less.
Actually, the FICHT and E-Tec systems are very similar, although BRP would probably not like to have them associated.
First the Ficht system. It is a direct injection system meaning that the fuel is injected directly into the compustion chamber when the piston is close to the top of it's stroke. This concept is great for fuel economy, power, and emissions, but there are technical challenges with injecting fuel into a hot, highly compressed combusion chamber.
The Ficht system injects the fuel by energizing a solenoid that serves as a plunger. The plunger pushes on a column of fuel that is piped to an injector. So, the order of operations is that an electric current is sent to a solenoid which causes a plunger to push fuel into the combusion chamber. The plunger is returned to it's original position by a spring. When the plunger is pulled back to it's "rest" position, it is re-filled with fuel ready for the next cycle.
Now, wanna know the big difference between Ficht & E-tec ?? There is no spring in the E-tec system. The plunger is returned to it's "rest" postion by reversing the current through the solenoid which makes the plunger shuttle in the opposite direction. Not really a big difference is there ?
The reversing polarity design does have several advantages to be sure, including the fact that the plunger can return to position faster, and it is quieter than the old spring system.
The E-tec system allows greater control of the solenoid that the Ficht system did, in fact my understanding is that during some running speeds and loads, the computer does not allow the plunger to travel it's entire stroke, i.e. the currrent is reversed pulling the solenoid back. The allows the computer to not only control when the fuel is injected, but how much fuel is injected.
I suspect (but do not know as fact) that the biggest advantage of E-tec over Ficht is the fact that lessons learned during the development of the technology were applied and the bugs of the system were worked out.
