[W126 Coupe] tornado air twister

[Chiappinelli, Joseph]

Ronny,
Don't know much about marine engines but my guess is they are not subject to the same strict emissions laws that cars are. To meet emission limits, the "burn" in an automobile engine must be very complete, i.e., very little if any excess unburned fuel that would prevent it from passing hydrocarbon limits. Any increase in combustion air by any means must be accompanied by a proportional increase in fuel to create the "ideal" combustion mixture required for clean burning. My VW GTI turbo, for example, has a mass air flow sensor (MAF) that measures the amount of air being supplied to the engine and sends signals to the engine management computer that regulates the amount of fuel needed. Of course, the computer is also sensing things such as engine temperature, air temperature, barometric pressure, load, and engine RPM just to name a few all for the purpose of keeping the ideal stoichimetric mix of air to fuel for efficient, clean combustion. These are all based on maps stored in the computer's memory for any combination of conditions. I had my computer re-flashed with a new set of maps by one of the popular aftermarket tuners which has boosted the hp/torque from a stock 180/170 to 237/250 simply by allowing the turbo to provide more boost and the fuel management system to provide more fuel according to the new set of curves in the program. 
J.Chip

________________________________

From: mbcoupes-bounces at mbcoupes.com on behalf of RONNY GEENEN
Sent: Sat 4/2/2005 12:45 AM
To: Mercedes Coupes Mailing Lists
Subject: Re: [W126 Coupe] tornado air twister



J.Chip wrote:


Uh...a few basics. For combustion engines to produce optimum, clean power
from an air/fuel mixture, that mixture must be at or close to an ideal
ratio. Forcing more air into the combustion chamber (i.e., turbo or
supercharging) than is normally drawn in by the volumetric displacement of
the piston moving in the cylinder (normal aspiration) will only produce
more power if the engine management system can measure the increase in air
and provide additional fuel to maintain the proper air/fuel ratio. That
said, for any given correct F/A ratio, a gain in the efficiency and speed
of the burn can be made by designs that atomize the mixture better. Some
combustion chambers are designed to "swirl" the mixture for presumably
better atomization. Even the physical placement of the spark plug has a
measurable effect on the efficiency of the burn. Once the burn or
combustion explosion takes place the force pushes the piston down against
the resistance of the mechanical inertia it is trying to overcome. Part of
that resistance is the backpressure of exhaust gases that must be pumped
through the exhaust manifold, and exhaust system. Properly designed headers
and free flowing exhausts reduce the back pressure and the amount of energy
wasted on pumping exhaust gases. This leaves more energy to do the work of
"moving the mechanicals".


To create more power in the cylinder you add more intake air by turbo
charging. That is correct. But you do not have to provide additional fuel,
because not all of the fuel in a normal combustion engine will burn. The
efficiency of a combustion engine as you also know is not very high.
At least that is the situation with 4 and 2 stroke engines on ships. I have
been a ships engineer for more than 10 years on Dutch oil tankers.

Ronny

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