A. Installing the TECgt System
A.1. How it All Works: The Two Pages You Need to Read
The goal behind Electromotive’s Total Engine Control product line is to provide complete, high-
resolution control of all functions of the modern engine, and to do so with a user-friendly interface.
Consequently, the
TECgt
is designed to easily control a huge number of complex engine management
functions through the hands of a user who is new at the game.
Engine Speed & Position = Crank Sensor…
What separates our engine management systems from those of our competitors is the fact that our
products are all designed around an ultra high-resolution ignition. For this reason, we use a 60(-2) tooth
crank trigger wheel to give the computer an extremely accurate engine position input. This is also the
reason that we do not support any other types of trigger inputs. Take, for instance, the flying magnet
trigger input used by some manufacturers: 8 cylinder engines have 4 magnets mounted to the crank trigger
wheel. Our 60(-2) tooth trigger has
15 TIMES MORE RESOLUTION!
From a magnetic sensor aimed at
the trigger wheel, the
TECgt
receives its input for engine speed and position.
Engine Load = MAP Sensor…
As nice as the 60(-2) tooth trigger wheel is for determining engine speed and position, more is
necessary to perform ignition and fuel control; namely a load input. While many OEM’s use Mass Airflow
(MAF) sensors to determine the airflow (and thus the load) of an engine, Electromotive systems are
designed around Manifold Air Pressure (MAP) sensors as the load-determining device. MAP sensors
simply plug into the intake manifold of the engine (after the throttle), and are inherently easier to install
than MAF sensors since they are not sensitive to vacuum leaks or engine airflow requirements. A 1-Bar
MAP sensor is designed for naturally aspirated engines. A 2-Bar sensor is used for turbo/supercharged
engines with up to 15psi (about 200kPa absolute) manifold boost. A 3-Bar sensor is good for up to 30psi
(300kPa), while a 4-Bar is good for up to 45psi (400kPa). Choose the appropriate sensor for the
application, and you are done.
Ignition Advance Control…
Once the MAP sensor and crank sensor are installed, the
TECgt
has inputs for RPM and load.
Under steady-state conditions on a fully warmed-up engine, these are the only necessary inputs for the
TECgt
to control the fuel and ignition curves. Control of the ignition advance curve is quite simple: there
is a table of RPM vs. MAP in which the desired ignition advance angle is entered for every point. The
table can be made in any size from 8
x
8 to 16
x
16 data points. Between each data point, there is a 256 point
interpolation occurring. This keeps the advance curve from “stepping” from point-to-point. Additionally,
it means that the engine can be tuned with only a few input numbers; some other systems on the market
rely on the tedious input of hundreds of numbers to obtain an ignition advance curve that is still not as
smooth between data points as ours.
Fuel Injector Control…
Control of the fuel curve is very simple as well. When the user first sets up a calibration, the
Tuning Wizard is generally used. The Wizard asks for the engine horsepower, peak RPM, number of
injectors, and the amount of manifold boost. From these, a raw fuel curve is established. Most
importantly, the User Adjustable Pulse Width (UAP/TOG) is established. UAP/TOG is the fuel injector
pulse width when the MAP sensor reading is full-scale (wide-open throttle on a 1-Bar MAP sensor, 15psi
boost on a 2-Bar sensor, etc.). The second variable that is established is the Injector Offset Time (IOT).
IOT and TOG can be thought of as the idle adjustment screw and the main power jet of a carburetor,
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TECgt Manual Version 2.0
- Page 9 -
©2008 Electromotive, Inc.
