Haltech E6M - Manual (Page 11)

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combination of engine speed and load, we have a direct reference to the amount of air that is
being drawn into the engine by means of this map.
The Haltech E6H/E6M uses a digital microcomputer to measure engine speed and load, and
uses them to access the base fuel map. The base fuel map is a look-up table of injector
opening times stored in non-volatile memory i.e. when power is switched off, the contents of
the memory are retained. By using the programming software, the contents of this memory
can be changed so that you can match injector opening times to the injectors you are using,
and to suit the requirements of your engine.
Having determined the base injection time, the microcomputer then performs a number of
adjustments to this value. Corrections for air temperature and barometric pressure are applied,
since these variables affect the density of air. Extra injection time is also added, when
necessary, for transient throttle movement and the temperature of the engine. At the end of all
these calculations, the final injection time is determined: the time for which the injectors are
actually held open.
Injection pulses usually occur one or more times per engine cycle. The ECU uses a trigger
signal locked to engine speed in order to determine when to inject. When it receives an
appropriate trigger, the ECU applies a magnetising current to the injector coils for precisely as
long as the final computed injection time, providing an extremely accurate delivery of fuel
that will exactly suit the engine's needs.
The ignition timing is determined in a similar way to the fuel needs. The Haltech E6H/E6M
ECU has a look-up table configured in the same way as for the fuel, but instead of the fuel
delivery in the table the Ignition Map contains the Ignition Advance for that point. This means
that the ignition point can be controlled with much greater accuracy then ever possible with
bob-weights and vacuum advance in a distributor.
The Advanced Mode Features of the E6H/E6M
The E6H/E6M is designed to be easily programmed, but also be capable of being used on a
wide variety of applications. A typical E6H/E6M installation could be : 4, 6 or 8 cylinders,
turbo/supercharged or normally aspirated, distributed ignition (only one ignition output), and
possibly using Closed Loop Control and/or Idle Speed Control. The E6H/E6M will control
this ‘typical’ engine without problem. It will also provide the ability to control some other
features, such as Turbo Wastegate Control, Thermofans, Torque Converter Clutch Lockup,
etc. (For a full list of Optional Outputs, see Chapter 16). This is what we would call a ‘Basic’
set-up.
Of course there are some exceptions to this basic set-up. One of the most obvious examples is
the Rotary engine. The ignition system for a Rotary is more complex than a piston engine.
There are also piston engines without distributors. These are known as Direct Fire engines.
They use multiple coils, either one for each plug or one for each pair of plugs. These are just a
couple of examples of non-basic set-ups. For the purposes of the E6H/E6M, we call these
‘Advanced’ set-ups.
The E6H/E6M can be programmed in either Basic or Advanced modes. The software is
identical for both, but in Advanced Mode, the special engine configurations can be employed.
The table below sets out what features are particular to the Advanced Mode. If your engine