Installation and adjustament manual
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DESCRIPTION
1. DESCRIPTION
1.1 Operational principles
LIS allows the conversion of gasoline injection engines,
provided with lambda sensor (oxygen sensor) and three-
way catalytic converter, by means of a continuous gaseous
LPG injection. The gas coming from the tank passes
through the Regulator-Vaporizer, which controls its
pressure and temperature, enters the Proportioner, which
sets the gas output to the Distributor according to the
information from the Electronic Control Unit (ECU),
and goes to the Distributor which provides for
proportioning the gas output to each single duct of the
intake manifold, maintaining at the same time a constant
pressure downstream of the Proportioner.
Since the system is compensated, and being the pressure
constant downstream of the Proportioner, it follows that
the Proportioner gas supply pressure increases with the
engine load, with important advantages in terms of
injection system speed reaction during transients.
LIS has been designed and developed for being suitable
to the most recent petrol injection systems.
The mapping is bi-dimensional, while the information
pertinent to Manifold Absolute Pressure (MAP) and RPM
is used to establish the amount of fuel that must be injected
for the best performance and emissions results. The
microprocessor modulates the amount of gas in function
of driving conditions so that performance and emissions
are constant even in different environmental conditions
and with fuel composition changes.
Fig.1
The microprocessor takes into account the engine’s
deterioration and automatically corrects the fuel’s
reference parameters.
The fuel management is further refined by other functions:
such as oxygen sensor management strategies, fuel
enrichment in acceleration transients, and fuel cut-off in
deceleration.
The ECU controls also other corollary functions of the
system, such as fuel level indicator, fuel change-over,
maximum RPM governor, and ignition system-triggered
fuel solenoid valves’ safety shut-off.
Interaction with the ECU can be achieved by means of a
serial interface with a portable PC or a tester . This is
possible for diagnostic purposes, as well as during the first
start-up after the completion of the conversion, when the
data files pertinent to the vehicle that is being converted
are uploaded from the PC into the ECU. For diagnostic a
check can be made for proper operation of the sensors
and of the Regulator-Vaporizer (RV) , while assessing
the quality of carburetion.
1.2 Programming the ECU
To properly operate, the ECU must be configured for the
vehicle on which LIS is installed.
The programming of the ECU is achieved by means of an
IBM-compatible personal computer and the proper
interface.
In Chapter 6 please find information on how to perform
this operation.
