Method for operating a rail vehicle

Abstract

A rail vehicle has a diesel engine, an engine radiator and a cooling circuit that connects the diesel engine to the engine radiator. A cooling liquid is circulated in the cooling circuit, a cooling liquid temperature of the circulated cooling liquid and an outer air temperature of the atmospheric outer air are detected. The outer air temperature is compared with the outer air limit temperature, the cooling power of the engine radiator is set in such a way that the cooling liquid temperature corresponds to a normal operating temperature if the outer air temperature is less than the outer air limit temperature. The cooling power of the engine radiator is set such that the cooling liquid temperature corresponds to a lower operating temperature below the normal operating temperature if the outer air temperature is greater than the outer air limit temperature.

Claims

1. A method for operating a rail vehicle having a diesel engine, an engine radiator and a cooling circuit connecting the diesel engine to the engine radiator, a cooling liquid being circulated in the cooling circuit, an electronic regulator for controlling the diesel engine, a cooling liquid temperature sensor, an outer air temperature sensor and an electronically controlled engine radiator fan, which comprises the steps of: detecting a cooling liquid temperature of the cooling liquid and an outer air temperature of an atmospheric outer air; comparing the outer air temperature with a previously defined outer air limit temperature; when the outer air temperature is less than the outer air limit temperature: regulating the cooling circuit for corresponding the cooling liquid temperature to a normal operating temperature; when the outer air temperature is greater than the outer air limit temperature the following steps are performed: travelling the diesel engine on partial load and regulating the cooling circuit so that the cooling liquid temperature corresponds to a lower operating temperature being lower than the normal operating temperature, the lower operating temperature corresponds to a lowest temperature at which the diesel engine can operate on full power; after travelling the diesel engine on partial load, travelling the diesel engine on full load and accelerating the rail vehicle to a final speed for raising the cooling liquid temperature on full load of the diesel engine from the lower operating temperature; and reaching the final speed with a cooling liquid temperature which is lower than a switch-off temperature of the diesel engine.

2. The method according to claim 1, which further comprises reducing a power consumption of an air conditioning system of the rail vehicle when the outer air temperature exceeds the outer air limit temperature.

3. The method according to claim 2, wherein a reduction of the power consumption takes place by a complete switch-off of the air conditioning system over a switch-off period.

4. The method according to claim 3, which further comprises basing the switch-off period on an amount of time the diesel engine operates on full load; detecting the full load of the diesel engine and an amount of time the diesel engine the diesel engine operates under full load.

5. The method according to claim 3, which further comprises: detecting a vehicle position of the rail vehicle when travelling on a stretch of rail; derivating ascents and descents of a stretch of rail; and performing a switch-off on a basis of the rail data the position of the rail vehicle.

6. The method according to claim 3, which further comprises: determining deviations from a timetable; and performing the switch-off taking into account deviations detected.

7. The method according to claim 3, which further comprises providing an internal temperature sensor, detecting at least one of an internal temperature in an interior of the rail vehicle or in an interior space of at least one carriage of the rail vehicle, wherein the switch-off is performed in dependence on a detected internal temperature.

8. The method according to claim 1, wherein a first value of a first difference between the normal operating temperature and the lower operating temperature is higher than a second value of a second difference between the normal operating temperature and the switch-off temperature.

9. The method according to claim 1, wherein the lower operating temperature is 60° C.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) Fig. 1 shows a diagram schematically indicating the temperature of the cooling water once with and once without radiator precooling as a function of time and

(2) FIG. 2 the power of the diesel engine as a function of time for different methods,

(3) FIG. 3 shows a perspective view on a rail vehicle,

(4) FIG. 4 shows a flow chart of a method for operating the rail vehicle.

DESCRIPTION OF THE INVENTION

(5) As already explained, the invention is based on the precooling of the cooling circuit of a diesel engine 15. An exemplary embodiment of the method according to the invention is used below with a rail vehicle 10 having a diesel engine 15 and an engine radiator 20. The diesel engine 15 and the engine radiator 20 are connected to each other via a cooling circuit 25. In the cooling circuit 25, a circulating pump 30 circulates a cooling liquid 35, in this case water. The process statuses of said system are shown in Table 1 below as a function of the coolant temperature.

(6) TABLE-US-00001 Coolant temperature in ° C. Process status −20 to 0 Diesel engine at standstill - preheating  0 to +20 Diesel engine start - diesel engine operation only possible at idling +20 to +60 Diesel engine can be operated at partial load +60 Diesel engine can be operated at full load +75 Start of thermostat opening (thermostat mechanically regulates cooling water feed to radiator) +85 Fan - start of precontrol according to special curve +88 Thermostat fully open (thermostat mechanically regulates cooling water feed to radiator) +93 Cooling water operating temperature (reference point for electronic regulator) +97 Yellow alarm - reduction of diesel engine power +99 Red alarm - emergency diesel engine shutdown

(7) The above table should be treated as an example. Other diesel engines 15 and other cooling circuits 25 could have other limit temperatures. During normal travel, the cooling liquid 35 is kept at a specific normal operating temperature. To this end, a radiator regulator 45 is used. The radiator regulator 45 is connected to a cooling liquid sensor 50, which detects the temperature of the cooling liquid 35. The radiator regulator 45 is also connected to a temperature sensor 55 to detect the outer air temperature (step 200).

(8) In the exemplary cooling circuit shown in Table 1, the normal operating temperature is 93° C. In other words, the cooling power of the engine radiator 20 is regulated by a radiator regulator 45 such that a cooling water temperature of 93° C. is established (step 205). If the heat output to be discharged is greater than the heat output that the engine radiator 20 is able to discharge, an upper switch-off temperature of 97° C. is quickly reached and a yellow alarm warning issued. If the vehicle control 60 receives a yellow alarm warning, it reduces the diesel engine power such that no overheating can take place. Apart from uphill driving, the driving profile of diesel locomotives is characterized in that a train is brought up to speed in a relatively short time at full load and then held at speed at partial load only. As is evident from the above table, the diesel engine can be operated at full load at 60° C. This means that at this temperature, the diesel engine is fully operational.

(9) If the outer air temperature exceeds a prespecified outer air limit temperature from which the engine radiator 20 is no longer able to discharge heat from the diesel engine 15 generated at full load, the method according to the invention is initiated.

(10) In the exemplary embodiment shown, therefore, at partial load, the temperature of the cooling liquid circulating in the cooling circuit is kept at 60° C. (step 210). After some time, not only the cooling liquid, but also the entire motor block, the radiators 20 and other components of the cooling circuit 25 reach this temperature. Therefore, the entire cooling circuit functions like a cold store. If the rail vehicle is accelerated, the diesel engine travels at full load (step 215). Due to the high outer temperature, the cooling power of the engine cooling circuit 25 is no longer sufficient to discharge the waste heat from the diesel engine 15. This causes the cooling liquid temperature to rise above the lower operating temperature (step 220). An electronic regulator 65 recognizes that the lower operating temperature has been exceeded and takes over full control of the cooling fans 70 of the engine radiator 20 (step 225). Due to the high heat to be discharged, the cooling liquid 35, the motor block 75 and the radiators 20, that is the entire cooling circuit 25, become increasing hotter. Only when the switch-off temperature is reached is the diesel engine power reduced (step 230). However, according to the invention, the diesel engine 15 could be operated for longer at full load because the cooling liquid, the motor block and the other components of the engine cooling only have to be brought to the switch-off temperature, in this case 97° C., in the case of excess heat. During this period, the diesel engine could run at full load. the internal temperature in the interior of the rail vehicle and/or in the interior space of at least one carriage of the rail vehicle is detected by a temperature sensor 100, wherein the switch-off is performed as a function of the detected internal temperature.

(11) This is illustrated in FIG. 1. The continuous line shows behavior during normal operation without the method according to the invention. It can be identified that, in normal operation, the temperature of the cooling circuit 25 is initially 93° C. In addition, it is assumed that the outer air temperature is greater than the outer air limit temperature. In this case, the rail vehicle 10 travels continually at full load. The heat of the diesel engine 15 can then no longer be discharged by the engine radiator 20. Relatively quickly, at time t1, the 97° C. switch-off temperatures are reached at which there is a yellow alarm and hence a reduction in the diesel engine power. The dashed line shows the temperature of the cooling liquid when incorporating an exemplary embodiment of the method according to the invention. It may be identified that the temperature of the cooling liquid has been brought to 60° C. as the lower operating temperature. Only gradually, is there an increase in the temperature of the cooling liquid 35 so that a substantially longer time has passed until the cooling water 35 reaches 97° C. at time t2. In an ideal case, the acceleration is completed before 97° C. is reached so that the engine cooling capacity is again sufficient to cool the temperature of the cooling liquid back down to 60° C.

(12) FIG. 2 shows the corresponding control of the diesel engine 15—once without the method according to the invention with the aid of the continuous line and once the control with the aid of the method according to the invention by means of the dashed line. It can be identified that, in the case of a normal control method without the invention, the power of the diesel engine at full load has to be reduced from 2400 MW to 2125 MW as early as time t1. According to the invention, the reduction is only necessary at time t2.

(13) FIG. 2 shows the corresponding control of the diesel engine—once without the method according to the invention with the aid of the continuous line and once the control with the aid of the method according to the invention by means of the dashed line. It can be identified that, in the case of a normal control method without the invention, the power of the diesel engine at full load has to be reduced from 2400 MW to 2125 MW as early as time t1. According to the invention, the reduction is only necessary at time t2.

(14) The time gap between t1 and t2 is the time for which the diesel engine can be operated for longer at full load.

(15) The method according to the invention can be easily integrated into already existing rail vehicles. The method according to the invention is hence very inexpensive.