6.2.4.1.4
Injection control
The fuel injection control is as follows:
•
Data from the crank angle and VIT are used to calculate the injection start.
•
The rail valves are activated to release the injection.
•
The time difference between the injection start signal and the injection start is known as
the injection dead-time. The injection start is sensed when the fuel quantity piston moves.
•
The stroke of the fuel quantity piston gives the injection quantity. The injection is stopped
when the fuel quantity piston is at the calculated stroke.
•
The WECS-9520 calculates the injection quantity, which is related to the control signal.
•
On the subsequent injection cycle, the calculation of the correct injection time includes
the measured injection dead-time.
•
The operation of the injection system is monitored at each cycle.
6.2.4.1.5
Emergency mode
If the fuel quantity sensor is defective, the control system changes the fuel command signal
from the related FCM-20 into a time period. The related cylinder is then controlled with timed
injection.
6.2.4.2
Exhaust valve control
6.2.4.2.1
Exhaust valve - function
The exhaust valve opens and closes once during each full turn of the crankshaft.
The valve stroke sensor measures the movement of the exhaust valve.
The FCM-20 increases the control outputs to the applicable signal level for the control valves.
6.2.4.2.2
Rail valve ON-time
The time between the start signal and the valve piston movement is measured and then shown
in the remote control.
6.2.4.2.3
Exhaust valve control
The exhaust valve movement is controlled as follows:
•
The opening command of the exhaust valve is calculated in relation to the crank angle
and VEO.
•
Operation of the rail valve to the open position.
•
Measured open deadtime: Displacement time from 0% to 15% of the valve stroke.
•
The close command of the exhaust valve is calculated in relation to the crank angle and
VEC.
•
Operation of the rail valve to the closed position (includes offsets, or input from the ICC
system (balance function).
•
Measured close deadtime: Displacement time from 100% to 15% of the valve stroke.
X92DF
AA00-0000-00AAB-043K-A
Operation Manual
Engine control system WECS-9520
Winterthur Gas & Diesel Ltd.
- 264 -
Issue 002 2020-08
