Vogels Autogas Systems VGI Hardware Manual
System Description and Installation
VGI Technical Manual 2014-01-14.pdf
Pagina 5 van 44
1.2 Inlet and outlet signals:
1.2.1 Inlet signals
Gas ECU
Cyl.1
Cyl.4
Cyl.3
Cyl.2
P
e
tr
o
l
in
je
c
to
rs
R.P.M
Engine temp.
MAP
G. Inj.1
G. Inj.4
G. Inj.3
G. Inj.2
Gas temp
. & pressure
Pressure
regulator
LPG-tank
Fuel level
Tank solenoid
Gas solenoid
Gas filter
Inlet signal
Function
Petrol-injection signals
The system uses as main inlet signal the petrol injection signals of each separate
petrol injector to determine the gas injector signal. The VGI system is a “slave system”
and follows the petrol injector signals to translate this signal to a gas injection signal.
The power supply of the petrol injectors is used as an ignition signal for the gas-ECU.
RPM signal
The RPM signal (engine speed) is used as a reference parameter to be able to
translate the petrol injection signal to the gas injection signal. Moreover the signal is
used to determine whether the engine is still running.
Water temperature signal
The water temperature is used as a condition for switch over from petrol to gas.
Moreover it’s being used for the correction of the fuel differences in cold engine
conditions. The temperature signal can be taken from a temperature sensor that is to
be placed in a water hose or from the original engine temperature sensor.
Gas pressure signal
By an increasing absolute gas pressure the density of the gas will increase as well and
so will the energy value per volume unit. To compensate this variation, a gas pressure
correction strategy is introduced to shorten in this case the injection duration. A very
low gas pressure will make the system switch back to petrol.
Gas temperature signal
An increasing gas temperature will lead to a lower gas density. To compensate this
variation, a gas temperature correction strategy is introduced to increase in this case
the injection duration.
Fuel level signal
The fuel level sensor gives the gas ECU an indication of the remaining fuel in the tank.
The gas ECU displays the fuel level on the fuel switch.
MAP signal
The manifold absolute pressure signal can be used as an option to determine the
pressure difference between the inlet and outlet of the gas injectors.
Lambda signal
As an option the lambda signal can be connected to the gas ECU to display its value in
the interface software. This can be beneficial during the calibration of the vehicle.
