Basic Description Of The System - KTM 2003 950 Adventure Repair Manual

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BASIC DESCRIPTION OF THE SYSTEM

Fuel system:
Fuel is drawn in by the fuel pump via the fuel screen and pumped through the fuel filter to the pressure regulator. All of these
components are located in the tank.
Since the fuel pump's flow rate and flow pressure are considerably higher than required by the injection system, a constant
pressure of 343 kPa (3.5 bar) is selected by means of the pressure regulator. The excess fuel returns to the fuel tank
unpressurized.
The pressurized fuel flows from the pressure regulator to the injection valves and is injected into the induction manifold when
the injection valves are opened (induction manifold or indirect injection).
The system does not require an external return line since the pressure regulator is installed in the tank.
Injection:
The injection nozzles are controlled by the control unit based on the pressure conditions in the induction manifold (manifold air
pressure sensors) and the rotational speed (pulse generator), taking the corrective injection periods into account (see above) -
this applies to the lower load/speed range. The opening of the injection nozzles is calculated according to the speed and throttle
valve signals at higher loads or speeds.
The injection is sequential, i.e. each injection nozzle is individually controlled and the fuel injected into the intake port of the
respective cylinder.
Ignition:
The ignition is also controlled by the ECU using a conventional transistor ignition system. Both the ignition timing and the
closing angle are calculated according to a stored map.
The ignition timing is established based on the following information: rotational speed, position of the throttle valve, the coolant
temperature and the operating condition (idle/not in idle). The ignition timing is also reduced if the two octane selector
connectors are not connected (when using low-octane fuel).
Idle control:
The control unit controls the idle speed depending on the cooling liquid temperature by opening the throttle valve wider or less
wide with the idle speed control motor.
Trailing throttle fuel cutoff:
If the driver closes the throttle valve with the engine running at operating temperature at a speed of at least 5000 rpm (overrun
condition, i.e. the motorcycle is driving the engine), the control unit will interrupt the control of the injection valves until the
minimum speed drops below 5000 rpm. Purpose: to save fuel and improve exhaust emissions.
Speed limitation:
To avoid damage to the engine, the control of the injection nozzles is cut off at speeds exceeding 9600 rpm and the ignition
coils cut off at speeds exceeding 10100 rpm.
Secondary air control:
Fresh air is introduced into the exhaust through a valve during the warm-up stage to improve the emission quality and to reduce
the catalytic converter light-off time. Afterburning takes place.
Lambda control:
A lambda probe (one probe per cylinder) is used to find the ideal fuel/air ratio for the best possible combustion (at a mixture
ratio of 1 kg fuel and 14.7 kg air). The catalytic converter installed in the exhaust can operate at maximum efficiency (at a
maximum conversion rate).
The goal is to obtain the maximum lambda 1 air ratio, i.e. to make the air volume actually drawn in by the engine equivalent to
the air volume theoretically required (to burn the quantity of injected fuel).
If the quantity of drawn-in air is smaller (i.e. air deficiency), the mixture is rich (lambda less than 1).
If the quantity of drawn-in air is greater (i.e. excess air), the mixture is lean (lambda greater than 1).
Electronic power control (EPC):
Under certain operating conditions, the second throttle is controlled in accordance with the throttle valve position and speed.
Error detection/elimination:
An "FI" error lamp is installed in the multifunctional digital speedometer that lights up for 2 seconds after "Ignition on" (function
indicator) and goes out if the control unit fails to detect any errors.
The error lamp will stay on during operation if an error is detected; if the vehicle is standing (gear in neutral) the error lamp will
start to blink according to the respective error code.
The registered error codes can be read out through the diagnostics connector using the KTM diagnostics tool and deleted after
the error has been eliminated.