Bosch Monomotronic Spi Integrated Injection-Ignition System; Introduction; System Operating Strategies - Fiat Bravo Service Manual

Bravo-Brava

BOSCH MONOMOTRONIC SPI INTEGRATED INJECTION-IGNITION SYSTEM

Introduction

The BOSCH MONOMOTRONIC SPI control system is an integrated system and thus governs engine
injection and ignition by means of a single electronic control unit.
This is an S.P.I, system, in other words only one injector controls fuel injection point and pulse duration
upstream of the throttle and the instant when a spark is triggered in the combustion chamber of each
cylinder (advance angle).
The MONOMOTRONIC engine control system works on the basis of engine load information deter-
mined by throttle angle/rpm (a/n). In other words, fuel requirements and advance settings are calculat-
ed on the basis of throttle opening angle of throttle and engine rpm.
This system is equipped with a LAMBDA probe. The system corrects injection pulse constant according
to whether the lambda probe indicates a rich or lean mixture. A closed-loop control system is therefore
set up.

SYSTEM OPERATING STRATEGIES

The management software resident in the E C U memory comprises a set of strategies. Each of these con-
trols a specific system control function.
Each strategy uses the various inputs listed above to process a set of parameters, using data maps saved
in specific areas of the E C U . The resulting data output is used to control system actuators, in other words
the devices used to operate the engine.
The management strategies control the moment of ignition and temperature/pressure of intake air at dif-
ferent engine speeds in order to ensure even engine runnind regardless of changes in environmental
conditions and applied loads. They must also control and manage injection so that the stoichiometric ra-
tio (air/fuel) is maintained within optimal levels.
System management strategies are essentially as follows:
1. injection management;
2. ignition management;
3. engine idle control;
4. fuel vapour recirculation management;
5. controlling knock;
6. heating/ventilation system management;
7. system self-adaption;
8. Fiat CODE lock management;
9. test management.
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Engine
Fuel system
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