Miu Injection System; Transparency - APRILIA SR MAX 125 ie Service Station Manual

SR MAX 125 ie
1 Throttle body and electronic injection control unit (MIU)
2
3
4 Injection load remote control
5 Water temperature sensor
6
7
8
9
10
11 Diagnostics socket connector

MIU injection system

This vehicle is fitted with an integrated injection and ignition system.
Injection is indirect in the manifold through an electro-injector.
The injection and ignition are timed on the four-stroke cycle by means of a tone wheel keyed on to the
crankshaft (24-2 teeth) and pick-up sensor.
Combustion and ignition are managed on the basis of engine revs and throttle valve opening. Further
corrections are made according to the following parameters:
- Coolant temperature.
- Intake air temperature
- Lambda probe
The system implements an idle feeding correction with cold engine through a Stepper motor on a by-
pass circuit of the throttle valve. The control unit manages the Stepper motor and the injector opening
time, thereby ensuring the idle steadiness and the proper combustion.
In all conditions of use, mixture preparation is managed by modifying the injector opening time.
The fuel system pressure is kept constant based on the ambient pressure.
The fuel supply circuit consists of:
- Fuel pump
- Fuel filter
- Injector
- Pressure regulator
The pump, the filter and the regulator are placed inside the fuel tank on a single support.
The injector is connected by two pipes provided with quick couplings. This allows obtaining a continuous
circulation, thereby avoiding the risk of fuel boiling. The pressure regulator is situated at the end of the
circuit.
The fuel pump is controlled by the MIU control unit; this ensures safety of the vehicle.
The ignition circuit consists of:
- HV coil
- HV cable
- Shielded cap

TRANSPARENCY

Specification
Fuel injector
Instrument panel
Fuel pump
HV coil
Lambda Probe
Engine Speed sensor
Battery
Injection
Desc./Quantity
12V - 12 Ah
INJEC - 159