ECM Control Strategy The engine control module
is involved with a variety of functions such as: (Fig.
3)
•
Individual injector activation
•
Engine idle speed control to ensure smooth
engine idling independent of engine load
•
Ride comfort function such as anti jerk control:
The CDI control module detects irregularities in
engine speed (resulting, for example, from load
changes or gear shift) from the signal supplied by the
crankshaft position sensor and reduces them by
adjusting the quantity injected into each of the cylin-
ders
•
Constant RPM (high idle feature) for ambulance
vehicle bodies equipped with electrical appliances
•
Starter control, immobilizer, cruise control, kick
down, air conditioner
•
Maintenance computer ASSYST (optional)
•
Glow plug for pre-heating, post heating and
intermittent heating
•
Error code memory/diagnostics, communication
interface for diagnosis and handling the fault codes
•
The maximum vehicle speed is programmable
from 19–82 m.p.h. The standard is 82 m.p.h.
Fig. 2 ECM
1 - MASS AIR FLOW SENSOR
8 - CHARGE AIR PRESSURE SENSOR
2 - TURBOCHARGER SERVO MOTOR
9 - CHARGE AIR TEMPERATURE SENSOR
3 - CAMSHAFT POSITION SENSOR
10 - COOLANT TEMPERATURE SENSOR
4 - ENGINE OIL SENSOR
11 - FUEL RAIL PRESSURE SENSOR
5 - CRANKSHAFT POSITION SENSOR
12 - FUEL TEMPERATURE SENSOR
6 - PRESSURE REGULATOR VALVE
13 - FUEL QUANTITY CONTROL VALVE
7 - EGR VALVE
14 - AIR INTAKE PRESSURE SENSOR
8E - 4
ELECTRONIC CONTROL MODULES
VA
