Haltech E6K - Manual (Page 64)

58
Barometric
Compensation
Fixed
Barometric
Compensation
Sensing Engine
Load via TPS
Continuous
Compensation
Continuous Compensation
Baro Lock disabled Baro Lock enabled
Baro Lock
disabled
Internal
Barometric
Sensor
External 1Bar
MAP Sensor
Internal
Barometric
Sensor
External 1Bar
MAP Sensor
Set Spare A/D as Baro
Sensor Internal.
Connect nothing to the
MAP Input.
Connect the External
MAP Sensor to the MAP
Input and set the Spare
A/D to whatever function
you require.
Set Spare A/D as Baro
Sensor Internal.
Set Spare A/D as Baro
Sensor External.
Connect the external
MAP Sensor to the
Spare A/D input.
Set the Barometric
Pressure Lock (mBars).
No internal or external
pressure sensor
required.
Sensing Engine
Load via MAP
Continuous
Compensation
Initial Barometric
Pressure Sample
Initial Sample Value
ECU performs a check
when the fuel pump is
primed to sample the
barometric pressure
through an open throttle
butterfly. This initial
sample value may be
used for a constant
barometric pressure
value.
Method 1 Method 2 Method 3
Fluctuations in barometric pressure vary the density of the intake air of the engine. At lower
barometric pressure, the engine cannot breath in as much air, and therefore the amount of fuel
delivered to the engine must be reduced. This is necessary when a large change in altitude is
expected during a driving period (a Hill Climb event such as Pikes Peak in the USA is a good
example). The barometric correction on the E6K is a powerful and therefore relatively
complicated feature and this section aims to describe the different methods it can be
implemented with. The above flowchart is an overview of the different barometric
compensation methods available with the E6K.
The E6K begins with the basic idea that there are three ways to compensate for barometric
pressure variations. The first is to use a pressure sensor to continually supply the E6K with
barometric pressure data and then the E6K can adjust the injection times based on this
information. The second method takes a barometric pressure sample from the environment
when the car is first turned on and uses this value for the remainder of the time the car is
operated. The final method is to use a preset value for barometric pressure, irrespective of
what is going on in the surrounding environment.
Method 3 is the most basic form of correction and will be our starting point. When the E6K is
manufactured it is configured with a value of 1013mBars as the constant barometric pressure.