PEGASOS Locomotive Control System

Press article HEINZMANN (may, 2010)

Based on long-term experience with electronic speed governors in diesel locomotives, HEINZMANN GmbH in Schoenau, Germany, have continued developing and extending their PEGASOS digital control system for diesel-powered rail vehicles.

Applications

HEINZMANN´s PEGASOS covers both diesel-electric and diesel-hydraulic traction systems and can be applied in main line and shunting locomotives, diesel railcars and special rail vehicles like track maintenance equipment.
PEGASOS is in use in many parts of the world, controlling various engines with a wide range of speed, load and operating profiles. With its purely electric fuel actuator, PEGASOS is well suited to retrofit traction systems and can be ideally matched to the size of the engine involved.
For a couple of years now, PEGASOS (in combination with an EFI control unit) has also been used successfully on diesel engines upgraded to electronic fuel injection.

System description

Hardware and software of the system can be configured for the specific application, including sensors for engine speed, engine pressure and temperature measurement. All customary on-board voltages between 24 and 110 VDC can
be accommodated with governor inputs and outputs fully isolated from the locomotive power supply source. Custom-made functions can be incorporated in the PEGASOS software. In locomotive re-powering projects, PEGASOS system can be adapted to existing control systems and extended with application specific functions.

System functions

In diesel-electric traction systems the PEGASOS control system includes an intelligent generator excitation control function, designed to provide the optimum load setpoint for the diesel engine operation, related to engine speed and engine condition. Excitation of a variety of generators in different locomotive types is attained via an excitation amplifier module, which can be adapted to specific requirements.
As in multiple traction like diesel multiple units (railcars) and double-headed goods trains, a PWM signal or CAN bus link ensure load sharing between the engines.
The PEGASOS anti-wheel slip function is based on reduction of engine speed and/or generator excitation. Its method of operation can be selected from analogue or digital input signal types. Anyway, with the system adjusted properly, a state of wheel slip is rather improbable, HEINZMANN reports.
The advantages of a digital engine speed control include many ways of engine monitoring and optimising engine performance. Performance-related functions of the HEINZMANN PEGASOS governor are: fuel limitation at engine start-up; engine speed dependent limitation of fuel quantity or power, charge-air pressure or temperature dependent limitation of fuel quantity or engine output; engine speed dependent oil pressure monitoring; temperature dependent power limitation and/or engine speed reduction.
The speed governor operates in an all-speed governing mode. A special 3-D PID map allows optimum governor settings for a multitude of engine speed and load points.
Individual speed and load ramps can be programmed. Options for engine speed setpoint include up to 16 speed stages via 4 binary inputs; speed increase and decrease switch inputs; analogue voltage or current signal (0-5 VDC, 4-20 mA) and CAN bus. Even existing compressed air signals can be used via a pressure-current converter. The PC based DcDesk 2000 communication program is a very effective tool for diagnosis and parametrising, as HEINZMANN´s customers report.

PEGASOS features

Power supply voltage: 24 ... 110 VDC (by order)
Modular locomotive interface LCI 01 for up to 8 isolated I/O modules
Excitation signal amplifier (DC voltage, DC current or PWM signal)
I/Os assignable to every available measuring value and status signal
All I/Os potentially separated from locomotive grid
Optional CAN bus interface (for engine control and monitoring)
Two different excitation control modes:
- load control mode (excitation signal vs. engine speed),
- load governor mode (desired fuel rack position vs. engine speed)
Extended engine monitoring functions
(analogue or digital I/O extension modules with CAN bus link)
Human machine interface (ARGOS operation and display unit)

Additional features (on request)

1. Calculation of traction power

Based on analogue input signals representing traction current and traction voltage, the actual locomotive traction power is calculated in the control unit. The result may be displayed to the operator, it can also be used to limit the traction power during acceleration or in combination with the train heating system to avoid overload.

2. Excitation signal limitation

There are several modes of excitation signal limitation:
Traction power limitation (see 1.)
External request (dynamic brake, alarm, ...)
Charge air pressure depending limitation
Slip control via switch input
Slip control via analogue input
Engine speed depending excitation limit (programmable)

3. Multiple traction of 2 or more locomotives, based on

Speed droop (common speed setpoint)
Equal fuel (master/slave mode)
Equal excitation (master/slave mode)

4. Brake power limitation

Brake current detection and limitation to a maximum allowed value. Protect brake resistors from overloading, while brake system may operate with the highest possible efficiency.

5. Extended error memory

Error logging based on engine running hours and including various engine environment data.

PEGASOS benefits

Lower fuel consumption by reduction of minimum engine speed and/or automatic cylinder-shutoff in low idle (the latter only for engines with electronic fuel injection)
Reduced wear-out of electric traction motors
Adaptable to almost every locomotive type
Available for new or retrofit installations
Complete speed/load control system in compact design
Proven in multiple installations worldwide
Optimum engine power achieved by programmable load control
Prevention of traction wheel slip

Summary

HEINZMANN‘s PEGASOS locomotive control systems meet the specific requirements of the railroad market for both diesel-hydraulic and diesel-electric drives.

The combined speed/load control assures maximal traction efficiency by its variable excitation control for diesel-electric drives. The programmable load control can provide optimum engine power for each speed level and prevent traction wheel slip.

All fuel actuators are fully electric and require no mechanical drive.

The PEGASOS solution is available for conventional fuel injection as well as electronic fuel injection (EFI) systems. With a variety of selectable speed setting modes PEGASOS is suitable for many different engine control systems.

PEGASOS offers an universal retrofit opportunity for locomotives with hydraulic governors as well as for OEMs. It is adaptable for almost every locomotive type.

Sensors for engine pressure and temperature monitoring are part of the system.

HEINZMANN PEGASOS locomotive control systems are in operation all over the world, for example in Australia, Austria, Finland, France, Germany, Hungary, Sweden, Switzerland, USA, Russia and Ukraine. Systems with electronic fuel injection are running in China, India and USA.