The Basic function of the Micro controller based Governor (MCBG) is to control the Engine speed, based on throttle handle position (Notch). Secondly, it is to control load on the engine electrically through an interface with E-Type of excitation /microprocessor control, for maintaining a pre defined constant horsepower at each notch. Thirdly, limits the fuel based on air manifold pressure. It also shut down the engine, in case of low lube oil, engine over speed etc. The user can set the parameters through a LAPTOP/PC of his choice with in the permissible limits. MCBG also logs the data of system faults, the timing of locomotive engine speeds i.e. Notch positions and the details of parameters changes with a date and time stamp.
LAX-MCBG-8 Micro controller based Governor, has a self-diagnostics facility and displays various parameters of the engine on a 40x4 Vacuum florescent Display. In case of any fault, it initiates an appropriate action instantly, displays the fault message to the locomotive crew, and records the fault in the memory, to help the maintenance crew in rectifying the fault. MCBG has number of user
programmable parameters, which allows the crew to configure the governor to various types of diesel Engines and also allows to fine tune the system parameters to suit the individual requirements. The error logs can be read through a LAPTOP/PC.
Presently Hydraulic governors are used in the Diesel Locomotive to govern the engine speed of the locomotive at a specified notch Vs speed, independent of Load factor. If The load factor exceeds the limit, the engine will bough down to safe guard the Engine, with the help of a Load control potentiometer. Because of the complex mechanical and Hydraulic, assemblies, the down time for repairs and maintenance is very high for Hydraulic Governors.
Laxven Systems has developed a Micro Controller Based Governor with a State-of –the-art technology for controlling the speed of Diesel Electric Locomotives with more built in safety features and maintenance free technology. The Electronic Governor consists of a Control Unit mounted in the Driver’s Cabin and the Actuator is mounted on the engine. The Actuator can be mounted on the same engine base as that of the Wood ward Hydraulic Governor base for easy one to one replacement. Both the Control unit and Actuator is connected through a pair of cables. The Electronic Governor has a provision to measure the engine speed either from the tacho generator provided on the locomotive or from the sensor provided on the gear teeth of the engine.
The Governor controls the engine speed, based on the notch position selected by the Driver. Specific Engine RPM is maintained by using PID control algorithm through fuel rack position dynamically. A Stepper motor drive is used in the Actuator Unit to control the fuel rack of Diesel Engine. The Governor also controls load on the engine electrically, so as to limit horsepower at each notch to a preset level, through an electrical interface with the excitation system of Locomotive. Booster (Turbo) air pressure is measured through a pressure sensor mounted in the air manifold. Movement of fuel rack is limited as a function of this pressure so as to prevent incomplete combustion of fuel, black smoke, excessive engine temperature, fuel wastage etc caused by lack of air to burn the fuel. Two Lube oil pressure sensors are used to continuously monitor the Lube oil pressure to shut down the engine, if the lube oil pressure is less than the specified pressure at each notch position and engine RPM.
Hunt free Engine speed.
Fuel efficient and less pollution by controlling effectively the combustion of fuel
Load control interface with Excitation system for Constant Horsepower at each notch.
User settable parameters for optimization of performance of different class of locomotive.
High torque DC stepper motor is used for better control of position of the fuel rack.
Digital PID control requires no adjustments, once the class, like WDG2, WDM4 etc., of the locomotive is decided. No need of individual tuning for each engine. The PID parameters are same for the same class of locomotive and can be entered numerically through user settable parameters.
No rack and pinion drive in the actuator
Automatic shutdown of the engine by bringing fuel rack to zero, in case of power failures or any major equipment malfunction without clutch mechanism.
Linear Transducer for feedback of actuator position
Redundant lube oil sensor is provided to avoid online locomotive failure due to failure of lube oil sensor.
Display shows all the engine parameters continuously and as and when any specific events for attention.
On line fault diagnostics and fault message display
Data logging of Errors and the durations of notch timings with date and stamp on non-volatile memory. Memory can be down loaded through RS 232 C communication port through a Laptop at any time.
User settable parameters through a LAPTOP with user friendly menu driver options:
For Notch wise RPM
For Notch wise Horsepower
For Lube oil pressure at each Notch RPM and time delays in building up of pressures.
For Booster Air pressure Vs fuel limit
For PID control settings
A high compression strength spring is provided to drive back the fuel rack to NO fuel when the power failure occurs and during any malfunction occurs in the system
Self test diagnostic facilities and Electronic and Mechanical over speed test facilities are provided.
All module are plugged type, for better serviceability
Minimized wiring for better reliability
Switch Mode Power Supply with built in protections capable of working from 40V to 140V DC (18V during cranking)
Power Supply Voltage
Diesel Electric Locos - 40VDC to 140VDC. 18VDC for 0.8 seconds during cranking.
Speed Settings
8 Different Speed Settings selectable by Notch from Driver Desk.
Accuracy of Control
±3 RPM of desired Engine RPM for the notch
Display Parameters
Notch Position, Engine RPM
Fuel rack position
Booster (Turbo) Air Pressure
Lube Oil Pressure
Fuel Oil Pressure
Load Control Position
Pressure Sensor Range / Accuracy
Lube Oil Pressure - 0 to 10 kg / cm2
Fuel Oil Pressure - 0 to 10 kg / cm2
Booster (Turbo) Air Pressure - 0 to 10 kg / cm2
Speed Sensing Mechanism
(a)Tacho generator or
(b) Speed Sensor mounted on Engine
Inputs Speed Sensor - 2 inputs for redundancy Digital inputs - All inputs are optically isolated, reverse polarity and surge protected operating at 72VDC
Display
20 character x 4 lines Vacuum fluorescent display for Engine Parameters, fault messages and diagnostic messages
Communication Interface
• RS 485 for communication with other Microprocessor based systems in the locomotive
• RS 232 for interface to PC / Laptop
Actuator Unit
Rack travel 34 mm (adjustable)
Working capacity grater than 16.3 Nm
