System and method for locomotive engine cranking
View Patent ↗In a method of operating a starting system coupled to a crankshaft of a vehicle engine, during engine starting, torque supplied by the starting system to the engine is continuously adjusted to provide more than two levels based on operating conditions of the vehicle or engine.
1. A method of operating a starting system coupled to a crankshaft of a vehicle engine, comprising:
during engine starting, adjusting torque supplied by the starting system to the vehicle engine based on operating conditions to provide more than two torque levels, and where the adjusting torque includes adjusting torque supplied via a three-phase alternator in the starting system by continuous adjustment of a field shunting of the three-phase alternator.
2. The method of claim 1 , wherein a transistor in parallel with a field winding generates a pulse width modulated signal to continuously shunt the field of the three-phase alternator.
3. The method of claim 1 , where the continuous adjustment of field shunting is provided via at least one transistor in parallel to a field winding of the three-phase alternator.
4. The method of claim 3 further comprising, coupling the at least one transistor to the field winding to shunt the field winding during engine starting, and connecting the at least one transistor to at least one other component of a vehicle after engine starting.
5. The method of claim 4 , wherein the at least one other component is at least one of a radiator fan, an air compressor, a battery charger, a traction field regulator, or an AC traction motor.
6. The method of claim 1 , wherein the adjusting torque includes adjusting torque of the three-phase alternator in the starting system by adjusting DC voltage supplied to an inverter coupled to the three-phase alternator.
7. The method of claim 6 , wherein adjusting the DC voltage includes adjusting at least one transistor coupled in parallel to a battery.
8. The method of claim 7 , wherein the at least one transistor is coupled to a boosting circuit during engine starting, and is connected to at least one other component of a vehicle after starting.
9. The method of claim 8 , wherein the at least one transistor is coupled to an inductor of the boosting circuit.
10. The method of claim 1 , wherein the adjusting torque includes adjusting torque supplied by the three-phase alternator operating in an induction mode.
11. The method of claim 10 further comprising, operating the three-phase alternator in a synchronous mode after engine starting.
12. The method of claim 10 further comprising, shorting a field winding of the three-phase alternator to operate the three-phase alternator in the induction mode.
13. The method of claim 12 where shorting the field winding is via a transistor.
14. The method of claim 1 , wherein the adjusting torque includes adjusting torque supplied by the three-phase alternator in the starting system via adjusting separate excitation of a field winding of the three-phase alternator.
15. The method of claim 14 further comprising, separately exciting the field winding by actuation of a transistor connected in series to the field winding.
16. The method of claim 15 further comprising, coupling the transistor to the field winding during engine starting, and coupling the transistor to at least one other component of a vehicle after engine starting.
17. A method of operating a three-phase alternator of a locomotive engine, the three-phase alternator having a field winding, comprising:
during a first engine condition including engine starting, coupling a transistor in parallel to the field winding, and adjusting alternator torque supplied to the locomotive engine to provide more than two torque levels by repeatedly adjusting shunting of the field winding, the field winding adjusted via modulation of the transistor; and
during a second engine condition after starting, coupling the transistor to a locomotive component other than the field winding, and controlling operation of the locomotive component by adjusting the transistor.
18. The method of claim 17 , where the locomotive component includes at least one of a radiator fan, an air compressor, a battery charger, a traction field regulator, or an AC traction motor, and where the field winding is adjusted via pulse width modulation of the transistor.
19. A system for a locomotive, comprising:
an engine;
an AC traction motor including a traction inverter;
a DC battery coupled to the traction inverter;
an alternator including an armature, rotor, and a field winding;
a switching circuit;
a transistor;
a locomotive component; and
a controller for adjusting torque supplied to the engine during engine cranking, the controller operating the switching circuit to couple the transistor to the field winding in parallel and adjusting shunting of the field winding continuously during engine cranking responsive to operating conditions to adjust alternator torque supplied to the engine; and the controller operating the switching circuit to couple the transistor to the locomotive component after engine starting during selected operating conditions to control operation of the locomotive component.
20. The system of claim 19 , where the controller adjusts a field shunting in real-time responsive to a desired engine speed starting profile, and wherein the locomotive component is at least one of a radiator fan, an air compressor, a battery charger, a traction field regulator, or an AC traction motor.