What is claimed is:
1. A fluid friction clutch, in particular for the fan of the radiator of an internal combustion engine, with a drive shaft, with a first clutch element mounted fixed against rotation on the front end of the drive side of the drive shaft, with a second clutch element mounted rotatably upon the driven side of the drive shaft, with a valve element, which controls the supply of a viscous fluid for the fluid frictional coupling of the first and the second clutch elements, and with a solenoid control for the valve element comprising a piston rod provided coaxially within the hollow drive shaft, the front end of which projecting from the drive shaft and axially operating the valve element against the force of a return spring, an anchor provided on the rear end of the piston rod, and an armature coil coaxially surrounding the anchor, thereby characterized, that the anchor (28) is guided coaxially within the drive shaft (12), that the drive shaft (12), at least in the part guiding the anchor (28), is comprised of a soft magnetic material with a non-magnetic separation gap (38), that the armature coil (34) is seated in a magnet body (32) of soft magnetic material coaxially surrounding the drive shaft (12) and that the drive shaft (12) is rotatable within the magnet body (12).
2. The fluid friction clutch in accordance with claim 1 wherein the drive shaft (12) is mounted in the magnet body (32) via roller bearings (36).
3. The fluid friction clutch in accordance with claim 1 wherein the anchor (28) is guided within a widening of the borehole of the axial inner bore of the drive shaft (12).
4. The fluid friction clutch in accordance with claim 1 wherein the solenoid control is a proportional solenoid or an ON-OFF switch magnet.
5. The fluid friction clutch in accordance with claim 1 wherein in the axial area transitioned by the rear end surface of the anchor (28) during the stroke movement thereof, within the separation gap (38), a widening of the shoulder (44) of the drive shaft (12) is provided which increases in diameter towards said rear end.
6. The fluid friction clutch in accordance with claim 5 wherein the separation gap (38) is formed by a ring of a non-magnetizeable material interrupting, and seated in, the drive shaft (12).
7. The fluid friction clutch in accordance with claim 1 wherein the stroke position of the anchor (28) is controlled by the amplitude of the current supplied to the armature coil (34).
8. The fluid friction clutch in accordance with claim 1 wherein stored armature coil (34) is time-wise energized in pulses, and the stroke position of the anchor (28) is determined by the pulse frequency of the energization.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method for detecting an opening and closing of a pilot operated solenoid valve for a hydrogen tank, the method comprising:
receiving a valve opening command;
determining whether valve driving inputoutput signals responding to the valve opening command are abnormal;
checking a pressure inside a high pressure hydrogen pipe when it is determined that the valve driving inputoutput signals are normal; and
outputting a valve opening signal when the checked pressure satisfies a valve opening condition.
2. The method of claim 1, further comprising:
prior to receiving the valve opening command, readying to wait for the input of the valve opening command, wherein in the readying, a valve closing signal is output.
3. The method of claim 2, wherein if it is determined that the valve driving inputoutput signals are abnormal by comparing the valve driving inputoutput signals, the process proceeds to the readying to output the valve closing signal.
4. The method of claim 1, wherein the valve opening condition is set to measure the pressure inside the high pressure hydrogen pipe at a predetermined period and determine that the valve is opened when a pressure difference is maintained at a value of a preset reference pressure or less for a preset reference time or more by comparing continuously measured values.
5. The method of claim 1, wherein the valve opening condition is set to measure the pressure inside the high pressure hydrogen pipe at a period of about 100 ms and determine that the valve is opened when a pressure difference is maintained at a value of 2 MPa or less for 500 ms or more by comparing continuously measured values.
6. The method of claim 1, wherein in the checking of the pressure, it is determined that the valve is closed before the valve opening condition is satisfied to output the valve closing signal.
7. The method of claim 1, wherein the valve driving inputoutput signals are PWM inputoutput signals.
8. An apparatus for detecting an opening and closing of a pilot operated solenoid valve for a hydrogen tank, the apparatus comprising:
a pilot operated solenoid valve arranged at an outlet of the hydrogen tank;
a high pressure hydrogen pipe configured to connect between the pilot operated solenoid valve and a fuel cell stack;
a pressure sensor arranged in the high pressure hydrogen pipe to measure the pressure inside the pipe; and
a controller configured to determine whether the pilot operated solenoid valve is opened,
wherein the controller is configured to receive a pressure inside the pipe from the pressure sensor to determine that the valve is opened when the change in pressure inside the pipe satisfies a preset valve opening condition and output a valve opening signal.
9. The apparatus of claim 8, wherein the controller is configured to receive a valve opening command from an upper controller, output a valve closing signal prior to receiving the valve opening command, and determine whether the valve is opened based on whether the valve opening condition is satisfied only when receiving the valve opening command.
10. The apparatus of claim 9, wherein the controller is configured to determine whether the valve is opened based on whether the valve opening condition is satisfied only when valve driving inputoutput signals are not abnormal by comparing the valve driving inputoutput signals at the time of inputting the valve opening command and if it is determined that the valve driving inputoutput signals are abnormal, output a valve closing signal.
11. The apparatus of claim 8, wherein the valve opening condition is set to measure the pressure inside the high pressure hydrogen pipe at a predetermined period and determine that the valve is opened when a pressure difference is maintained at a value of a preset reference pressure or less for a preset reference time or more by comparing the continuously measured values.
12. The apparatus of claim 8, wherein the valve opening condition is set to measure the pressure inside the high pressure hydrogen pipe at a period of about 100 ms and determine that the valve is opened when a pressure difference is maintained at a value of 2 MPa or less for 500 ms or more by comparing the continuously measured values.
13. The apparatus of claim 10, wherein the valve driving inputoutput signals are PWM inputoutput signals.