SECTION 5. Engine operation details
5.4
Auto calibration
A H
ORNET
-III with analogue (brushed) pump needs to perform this step for a sufficiently precise guess of the
pump’s voltage for full RPM for a correct throttle response until the correct voltage is known.
The reason for this is that the brushed pump’s characteristic curves are not entirely consistent and may differ
between between devices of the same model, or even due to different ambient conditions. Brushless pumps do
not have these inconsistencies up to negligible differences and do not require auto calibration.
The auto calibration sequence consists of the following steps.
1. Starting at idle RPM, the engine accelerates to the
calibration
RPM.
2. After reaching the calibration RPM, the ECU waits for the RPM, fuel flow and pump voltage to stabilise.
3. The engine then drops back to idle RPM.
4. Now that the pump voltage is known for idle and calibration RPM, an educated guess for the correct
pump voltage for full RPM can be made.
After completing the auto calibration, the engine will be in
automatic
mode (see Section 5.5).
5.5
Automatic mode
This is the standard mode of engine operation and will display as
AUTO
on the GSU. If a H
ORNET
-III with
analogue (brushed) fuel pump is used, the engine will run in mode
AUTO*
(automatic, pump voltage for full
RPM not yet known) until reaching full RPM once.
• The RPM between idle and full RPM is controlled by the user’s input.
• This is achieved by an RPM and temperature dependent fuel flow.
• Telemetry data is transmitted if a telemetry module is connected and configured.
• Temperature and RPM are monitored by the ECU, as are the battery voltage, the RC signal and the fuel
pump voltage.
• In case the RC signal is lost or outside acceptable ranges, the ECU will switch to
failsafe
mode (Section
5.6
Fail-safe mode
If the RC signal is lost, the ECU will switch to
fail-safe
mode, which can be configured in the corresponding
menu via GSU (see Section 4.5.1). By default, the fail-safe mode is off, meaning the engine will shut down if
the RC signal is lost.
•
FAILSAFE DELAY
: The time (in
s
) the ECU will operate normally if the RC signal is lost before switching
to fail-safe mode.
Setting this to 0 will deactivate the fail-safe mode
.
•
FAILSAFE TIMEOUT
: The time (in
s
) the ECU is allowed to operate in
fail-safe
mode. After this time, the
engine will shut down by stopping the fuel pump. The default is 0, meaning instant shutdown.
•
FAILSAFE THROTTLE
: The throttle position the ECU assumes in
fail-safe
mode. Default is 0, so the
engine will go to idle speed.
If the fail-safe program was activated and for how long it ran during the last engine run can be found on a
status screen via GSU (see Section 4.2).
5.7
Cool-down mode
After the engine came to a standstill after turning off, the starter will cool the engine until the measured tem-
perature is below the corresponding threshold.
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