Title of Invention

A CONTROLLER FOR A FLUID PUMP

Abstract When a motor locking condition is detected at the time of start of a fuel pump 11, an armature coil 21 is energized in a first non-rotary pattern established previously. Thereby, the current continues flowing into the armature coil of the predetermined phase, and it can suppress that the armature coil receives breakage with the heat. Moreover, the first non-rotary pattern is the pattern in which heat is generated to the extent that the armature coil 21 does not perform fault generation of heat. The fuel pump 11 can be warmed, without burning off the armature coil, and the motor locking due to a freezing can be canceled.
Full Text

CONTROLLER FOR FLUID PUMP
[Field of the Invention]
The present invention relates to a controller for a fluid pump,
[Background of the Invention]
Conventionally, the brushless fuel pump for the vehicles which has a brushless motor as a driving source is known (for example, refer to patent documents 1). Here, in the brushless motor, the rotor is rotated by changing the energization to the armature coil sequentially according to the rotary position of the rotor. [Patent documents 1] JP-11-270468A
[Description of the Invention] [Problems to be Solved by the Invention]
When a vehicle on which a fuel pump is mounted is placed under low temperature environment, it may be in the condition (henceforth the "motor locking condition") that bearing of the shaft freezes and the revolution of the motor is prevented. Moreover, foreign matter, such as the dust which was being mixed into the fuel, may be caught between the rotor and the stator, or may be introduced into an impeller of the pump section, which may causes the motor locking condition.
In the motor locking condition, the rotary position of the rotor does not change. Therefore, when an energization control which rotates the rotor while the motor locking condition has not been canceled is performed, the energization of the predetermined phase coil is continued. And if this energized state is continued, the heating value of the predetermined phase coil will increase, and the

problem that that phase coil receives breakage with the heat finally may be produced.
The present invention is made in view of the above-mentioned problem, and an object of the present invention is to provide the controller for a fluid pump which can cancel the motor locking condition or can suppress the generation of a motor locking condition.
[Means for Solving the Problem]
Hereafter, the means effective in solving the above-mentioned subject, the function, and advantages are explained.
An invention claimed in claim 1 relates to a controller for a fluid pump which includes a stator having an armature coil of multiphase, and a rotor having a magnetic filed pole confronting to the stator. The controller controls the fluid pump of brushless type in which the rotor is rotated by sequentially switching an energization of the armature coil of each phase so as to introduce and discharge a fluid. Furthermore, the controller includes an energization means for energizing the armature coil either in a first energizing pattern in which the rotor is rotated by switching the energization of the armature coil of each phase according to a rotational position of the rotor, or in a second energizing pattern in which the armature coil is energized or un-energized in such a manner that the rotor is not rotated.
In the fluid pump, a bearing of a shaft of the rotor freezes, or foreign matter, such as the dust contained in the fluid, is put between the rotor and the stator, which may causes a condition (locking condition) in which a rotation of the rotor is prevented. In such a case, when the armature coil of each phase is energized in a revolution pattern in which the energization changes to according to the rotary position of the magnet rotor, the magnet rotor is locked and its rotary position does

not change, whereby the energization of the armature coil of the predetermined phase will be continued. And by continuing performing energization to the armature coil of the predetermined phase, the heating value of the armature coil increases, and there is a possibility that the armature coil may receive breakage with the heat.
In the present invention, it is possible to energize the armature coil for a predetermined period in the second energization patterns in which the energization and un-energizing are alternately changed while the rotor is not rotated. By changing energization and un-energizing to the armature coil of each phase in the second energization patterns, the energization of the armature coil of the predetermined phase continues, whereby it can restrain that the heating value of the armature coil increases. As a result, it becomes possible to suppress that the armature coil receives breakage with the heat.
While the over-heat is restricted, the armature coil effectively generates heat by energizing the armature coil for a predetermined period in the second energization pattern. For this reason, the fuel pump can be warmed effectively and it becomes possible to cancel or restrict the locked condition due to freezing as that result.
Moreover, the magnet rotor can be attracted toward the stator by energizing the armature coil of the predetermined phase. And the magnet rotor moves toward the stator slightly due to a clearance produced between the shaft and bearings. Therefore, it becomes possible to vibrate the magnet rotor in a diameter direction by switching each of the armature coil between energization and un-energization in the second energization pattern. The foreign matters disposed between the magnet rotor and the stator exists being compressed in a diameter direction. But it becomes possible to remove the foreign matters from between the magnet rotor and the stators by vibrating the magnet rotor in the

diameter direction. As a result, it becomes possible to cancel or restrain the locking condition due to foreign matters.
As described in claim 2, the second energizing pattern may be a predetermined pattern in which the energization and the un-energization are alternately changed along with a progress of time. The energization is not switched according to the rotary position. The energizing pattern can be a predetermined pattern in which the energization and the un-energization are alternately changed along with a progress of time.
In the invention claimed in claim 3, the energization means energizes the armature coil for a specified period in the second energizing pattern when the fluid pump is started. Thereby, even when the fuel pump is in the locking condition, it is possible to cancel the locking condition and to start the fuel pump.
In the invention claimed in claim 4, the energization means energizes the armature coil for a specified period in the second energizing pattern right after the fluid pump is stopped. Since the rotational energy of the rotor is high while the fluid pump is rotating, foreign matter, such as the dust mixed in the fluid, is flipped by the rotor. Therefore, it is rare during rotation of the fluid pump that the dust will be inserted and crowded between the rotor and the stator and it will be in the locking condition. On the other hand, although the rotor stops immediately after suspending the fluid pump, the fluid flows for inertia. Therefore, possibility that the foreign matter currently mixed in the fluid will be put between the rotor and the stator, and will be in the locking condition is higher than while the fluid pump is rotating. In the present invention, the armature coil is energized in the second energization patterns in which the energization and un-energizing are changed immediately after the fluid pump stops. By changing energization and un-energizing, it becomes possible that the rotor generates a vibration during a period in which the locking condition will be generated in a high possibility. . As a

result, it is possible to suppress the locking condition due to the foreign matters between the rotor and the stator. Besides, "immediately after suspending the fluid pump" represents a condition in which the flow of the fluid flows by its inertia while the rotor of the fluid pump has stopped.
2
In the invention claimed in claim 5, the energization means energizes the armature coil for a specified period in the second energizing pattern when a specified period has passed after the fluid pump is stopped. When the fluid pump is placed under low temperature environment after the fluid pump stopped, a bearing of the shaft of the rotor 23 freezes, and it falls into the motor locking condition. The fluid pump can be warmed by performing the energization in the second energization patterns for a predetennined period after specified time has passed from the stop of the fluid pump. While being able to suppress that bearing of the shaft of the rotor freezes, it becomes possible to suppress that it will be in the locking condition by freezing.
In the invention claimed in claim 6, in A controller for a fluid pump according to any one of claims 1 to 5, wherein the energization means energizes the armature coil for a specified period in the second energizing pattern every when a specified period has passed after the fluid pump is stopped. After the fluid pump stops, every when the specified time has passed, the fluid pump can be periodically warmed by performing energization in the second energization patterns during the predetermined period. Also when the fluid pump is left under low temperature environment for a long period of time, it can suppress that bearing of the shaft of the rotor freezes, and the locking condition due to freezing can be restricted.
In the invention claimed in claim 7, a temperature detecting means is provided for detect a temperature at a vicinity of the fluid pump, and the energization means energizes the armature coil for a specified period in the

second energizing pattern when the temperature detected by the temperature detecting means is lower than or equal to a predetermined temperature after the fluid pump is stopped. The fluid pump can be warmed when the temperature around the fluid pump is not greater than a predetermined temperature and the possibility of locking condition due to freezing becomes high. And it becomes possible to suppress the motor locking condition due to freezing as the result.
In the invention claimed in claim 8, a lock detecting means is provided for detecting a lock condition of the fluid pump, and the energization means energizes the armature coil for a specified period in the second energizing pattern when the lock condition of the fluid pump is detected. Thereby, since the locking condition of the fluid pump is detectable, it becomes possible to perform energization in the second energization patterns at suitable time.
In the invention claimed in claim 9, the lock detecting means determines that the fluid pump is in the lock condition when an energizing condition of the armature coil of each phase is not changed and is continued for a specified period. The rotor rotates by changing the energization of the armature coil of each phase according to the rotary position of the rotor as above-mentioned. However, since the rotor does not rotate in the case of the locking condition, the predetermined energized state continues. Therefore, the condition which the rotor is not rotating, that is, the locking condition can be determined by detecting a condition in which the energized state of the armature coil continues for a specified time without changing.
The second energizing condition, as described in claim 10, can be a pattern in which the energization means energizes a specified two phases of the armature coil and un-energizes the other phase of the armature coil during an energization period in the second energizing pattern. Alternatively, as described in claim 11, the energization means simultaneously energizes the armature coil of

all phases during an energization period in the second energizing pattern. Thereby, the locking condition can be cancelled or suppressed. In particular, in invention claimed in claim 11, since the energization means simultaneously energizes the armature coil, it is possible to uniformly warm the whole fluid pump. Thereby, while cancellation of the locking condition by freezing becomes easy, it can suppress that it will be in the locking condition by freezing.
In the invention claimed in claim 12, the energization means intermittently energizes the armature coil during an energization period in the second energizing pattern. Thereby, it becomes possible to vibrate the rotor continuously in the diameter direction. As the result, it is easy to cancel a locking condition due to foreign matters such as dust and to restrict the locking condition.
In the invention claimed in claim 13, the energization means switches the energization of the armature coil of each phase according to the natural frequency of the rotor. Thereby, the amplitude of vibration of the rotor can be increased. As the result, it is easy to cancel a locking condition due to foreign matters such as dust and to restrict the locking condition.
[Best Mode of Carrying Out the Invention] [First embodiment]
Hereafter, an embodiment in which the present invention is applied to the fuel pump for a vehicle is described based on the drawing.
First, an entire configuration of a fuel pump is explained based on FIG. 1. A fuel pump 11 includes a pump section 13 and a brushless motors 14 which are accommodated in a cylindrical housing 12. In the pump section 13, a pump chamber 17 is defined by a pump casing 15 and a pump cover 16, which are press-inserted or connected by caulking to one end of the cylindrical housing 12. An impeller 18 is accommodated in the pump chamber 17. The impeller 18 is

engaged with a shaft 24 of the brushless motor 14, and rotates along with the shaft 24.
On the other hand, the brushless motor 14 is a brushless motor of a three-phase full-wave driving-type, for example, and is structured as follows. A cylindrical stator 19 is inserted into the cylinder housing 12. As shown in FIG. 2, six salient poles 20 are formed in this stator 19. Armature coils U21, V21, and W21 are wound around the salient poles 20 respectively in this series. Two armature coils U21, V21, and W21 are respectively provided and the armature coils of each phase are electrically connected in series, as shown in FIG. 3.
The magnet rotor 23 is arranged at the inner circumference side of the stator 19 of the six poles, which is structured as described above. The magnet rotor 23 has a rotor core 25 attached on the shaft 24, and eight magnets 26 which generate magnetic field and are adhered to an outer circumference of the rotor core 25 by adhesive. As shown in FIG. 2, the eight magnets 26 are arranged so that N-pole and S-pole are alternately located, thereby, the magnet rotor 23 of the eight poles are structured.
As shown in FIG. 1, one end of the shaft 24 of the magnet rotor 23 is rotatably supported by the bushing part 28 of the pump casing 15 through a bearing 27. Moreover, the other end of the shaft 24 is rotatably supported by a bearing holder 30 fixed in the cylindrical housing 12 through a bearing 29. A drive control circuit 31 of the three-phase full-wave driving-type is attached to the bearing holder 30. The drive control circuit 31 energizes the armature coils U21, V21, and W21 sequentially to drive the brushless motor 14. The housing cover 33 which has an outlet port 32 is engaged with an opening of the cylindrical housing 12 at a side of the drive control circuit 31.
When the impeller 18 of the pump section 13 is rotated by the brushless motor 14, the fuel in the fuel tank (not shown) is introduced into the pump chamber

17 through an inlet port (not shown) of the pump cover 16, and is discharged into the cylindrical housing 12 from the outlet port (not shown) of the pump casing 15. This fuel flows through a clearance between the stator 19 and the magnet rotor 23, is discharged into a fuel pipe (not shown) from the outlet port 32 of the housing cover 33, and is introduced into a fuel injector (not shown).
As shown in FIG. 4, a star connection of the three-phase armature coil U21, V21, and W21 is performed. Moreover, the drive control circuit 31 includes a control unit 35 and a switching element part 46 which switches an energization of each armature coil U21, V21, and W21 based on the output of the control unit 35. The switching element part 46 has six MOSFET (U1, U2, VI, V2, W1, W2). Each two of switching element parts 46 are connected in a shape of a bridge between battery voltage (+B) and gland. The intermediate junction of MOSFET is connected to the end of the armature coil U21, V21, and W21 which are star-connected. And, the battery voltage used as the actuation voltage (the applied voltage of the armature coil U21, V21, and W21) of the brushless motor 14 is inputted into the control unit 35.
An ignition switch (henceforth "IG switch") 36 which detects the engine start/stop requirement by a user is provided in the vehicle. The detection result of the IG switch 36 is inputted into the control unit 35. The start/stop of the fuel pump 11 is interlocked with the start/stop of the engine. Therefore, start and the stop of the fuel pump 11 can also be estimated according to the input from IG switch 36. Moreover, the temperature detecting means 37 is provided near the fuel pump 11, and the detection result by the temperature detecting means 37 is inputted into the control unit 35.
The drive control circuit 31 rotates the brushless motor 14 by a two-phase energization manner. In this case, the control unit 35 of the drive control circuit 31 detects the induction voltage generated in the armature coil 21 of the phase

which is not energized based on neutral point voltage, and detects the rotary place of the magnet rotor 23 based on this neutral point voltage. As shown in FIG. 5, the control unit 35 sequentially switches the upper and lower MOSFET (U1 - W2) of each phase based on a rotary position of the magnet rotor 23. And based on the energization patterns (henceforth "the revolution pattern") shown in FIG. 6, the armature coil 21 of the two phase among the three-phase is simultaneously energized so that the brushless motor 14 is rotated.
The control unit 35 can energize the armature coil 21 by the first and second non-rotary patterns that are energization patterns in which the magnet rotor 23 is not rotated other than energization with the revolution pattern shown in FIG. 6. The first and second non-rotary patterns are not patterns in which the MOSFET (U1-W2) is switched according to the rotary position of the magnet rotor 23. In the first and second non-rotary patterns, the upper and lower MOSFET are sequentially switched in such a manner as to be energized in a predetermined pattern.
When the motor locking condition is detected at the time of start of the fuel pump 11, the energization with these first and second non-rotary patterns are performed in a predetermined period by the control unit 35. Here, the motor locking condition is a condition in which the bearing of the shaft 24 freezes or the dust in the fuel is introduced between the magnet rotor 23 and the stator 19 or into the impeller 18, so that the revolution of the brushless motor 14 is prevented.
A detection of the motor locking condition is performed as follows. As described above, when the brushless motor 14 rotates, the control unit 35 sequentially switches the MOSFET (U1-W2) of each phase according to the rotary position of the magnet rotor 23. However, since the rotary position of the magnet rotor 23 does not change when it is in the motor locking condition, a certain energized state (switching state) continues after start of the fuel pump 11. The

control unit 35 measures the duration of the switching state, and when the duration is beyond specified time, it determines that it is in the motor locking condition.
FIG. 7 shows the first non-rotary pattern, and FIG. 8 shows the second non-rotary pattern in this embodiment. As shown in FIGS. 7 and 8, in the first and second non-rotary patterns, a specific two phases among the three phases are energized, and the other one phase is not energized. Specifically, the U-phase is energized in a positive direction for a specified period, and the V-phase is energized in a negative direction while the U-phase is energized in the positive direction. Moreover, the W-phase is not energized in a whole period. When it is energized in the first and the second non-rotary patterns, the armature coils U21, V21, and W21 are not switched according to the rotary position of the magnet rotor 23, so that the brushless motor 14 does not rotate.
In the first non-rotary pattern shown in FIG. 7, the armature coils U21, V21 of the U-phase and the V-phase are energized for a comparatively long time in which the armature coils U21, V21 does not generate over-heat. Since a comparatively prolonged energization is performed, when the armature coil 21 is energized in the first non-rotary pattern, the armature coil 21 generates heat effectively.
Moreover, in the second non-rotary pattern shown in FIG. 8, the armature coils U21, V21 of the U-phase and the V-phase, and V21 are intermittently energized for a comparatively short period. While energizing the armature coil 21 of the two phases, the magnet rotor 23 is attracted by the magnetic force in a specific direction by a small clearance of bearings 27, 29 and the shaft 24. And when energization is stopped, the attraction by the magnetic force is stopped and the magnet rotor 23 is returned to the initial position. Therefore, if the energization and un-energization are repeated in a short period like the second non-rotary pattern, the small vibration of the magnet rotor 23 is

performed in a diameter direction. Therefore, when the armature coil 21 is energized in the second non-rotary pattern, the dust between the magnet rotor 23 and the stator 19 and in the impeller 18 can be effectively removed. Besides, the period of the change waveform of energization and non-energization in the second non-rotary pattern is established as a natural frequency of the magnet rotor 23. For example, when the natural frequency of the magnet rotor 23 is 100Hz, as shown in FIG. 8, the period of the change waveform of energization and non-energization in the second non-rotary pattern is set to 10msec.
Then, the control procedure for canceling the motor locking condition at the time of start of the fuel pump 11 is explained. In this control, the armature coil 21 generates heat by energizing the armature coil 21 in the first non-rotary pattern, whereby the motor locking condition due to freezing is canceled. Moreover, by energizing the armature coil 21 in the second non-rotary pattern, the magnet rotor 23 and the impeller 18 are vibrated, and the motor locking condition due to the dust is canceled.
FIG. 9 is a flowchart which shows a control procedure for canceling the motor locking condition at the time of start of the fuel pump 11. The routine of FIG. 9 is performed by the control unit 35 after it is detected that the IG switch 36 is ON.
First, at step S101, a counter "n" is established as "0". Then, at step SI02, the armature coil 21 is energized in order to rotate the brushless motor 14. That is, according to the rotary position of the magnet rotor 23, the MOSFET (U1-W2) of each phase is switched, and the armature coil 21 of each phase is energized in the revolution pattern. At step SI03, it is determined whether it is in the motor locking condition. It is determined whether it is in the motor locking condition according to whether a certain switching state is continuing for specified period or more.

When the determination result of step S103 is NO, that is, when it is not in the motor locking condition, this routine is ended. And after this termination of the routine, the energization in the revolution pattern is continued, and the fuel pump 11 is rotated. Thereby, the charge and discharge of the fuel by the fuel pump 11 are performed. On the other hand, when the determination result of step 103 is YES, it progresses to step SI04 and specified time energization of the armature coil 21 is performed in the first non-rotary pattern. Thereby, the armature coil 21 of the energized phase generates heat.
At step SI 04, after performing specified time energization in the first nonrotary pattern, it progresses to step SI05, and the armature coil 21 is energized in order to make the brushless motor 14 rotate again. That is, according to the rotary position of the magnet rotor 23, the armature coil 21 of each phase is energized in the rotation mode. And at step SI 06, it is determined whether it is in the motor locking condition.
This routine is ended when the determination result at step SI06 is NO. And after this termination of the routine, the energization in the revolution pattern is continued, and the fuel pump 11 is rotated. On the other hand, when the determination result at step 106 is YES, it progresses to step SI 07 in which the armature coil 21 is energized for a specified period. Thereby, the magnet rotor 23 vibrates.
At step SI 08, the value of the counter "n" is increased by "1", and at step SI 09, it is determined whether the value of counter "n" is larger than a predetermined upper limit "nmax". When the determination result in step SI 09 is NO, it returns to step SI02 in which the brushless motor 14 is energized in the revolution pattern, and processings after step SI02, such a determination of a motor locking condition, are performed again.
On the other hand, when the determination result at step SI09 is YES, it

progresses to step S110. Even if the executions of the processing of step S102 to the step SI07 are performed "nmax" times, when the motor locking condition is not canceled, a malfunction may have occurred in the brushless motor 14. So, at step S110, a lamp is turned ON to notify the user that the brushless motor 14 may have malfunction, and this routine is ended.
Next, the control procedure for preventing the fuel pump 11 from being in the motor locking condition after the fuel pump 11 is stopped will be explained. In this control, when specified time has elapsed after the fuel pump 11 is stopped, the armature coil 21 is energized in the first non-rotary pattern so that the armature coil 21 generates heat and the motor locking condition due to freezing is prevented.
FIG. 10 is a flowchart showing a control procedure for preventing the fuel pump 11 from being in the motor locking condition after the fuel pump 11 is stopped. The stop of the fuel pump 11 is detected on turning OFF the IG switch 36. The routine of FIG. 10 is performed by the control unit 35 after the IG switch 36 is turned OFF.
First, at step S201, the timer counter "t" is established at "0". At step S202, the value of the timer counter T is increased by "1". At step S203, it is determined whether the timer counter "t" is a preset value "T". The value "T" is established previously. For example, the value "T" corresponds to 5 hours. In step S203, it is determined whether the predetermined time has passed after the IG switch 36 is turned OFF.
When the determination result at step S203 is NO, it returns to step S202, and it carries out by repeating the step which increases the timer counter "t". On the other hand, when the determination result at step S204 is YES, it progresses to step S204 in which the armature coil 21 is energized for a specified time in the first non-rotary pattern, and this routine is ended.
According to this embodiment explained above, the following advantages

are obtained.
When the fuel pump 11 is in the motor locking condition, the rotary position of the magnet rotor 23 does not change. Therefore, when the armature coil of each phase is energized in the revolution pattern in which the energization changes to according to the rotary position of the magnet rotor 23, the energization of the armature coil 21 of the predetermined phase will be continued. And by continuing performing energization to the armature coil 21 of the predetermined phase, the heating value of the armature coil 21 increases, and there is a possibility that the armature coil 21 may receive breakage with the heat.
In this embodiment, when the motor locking condition is detected at the time of start of the fuel pump 11 the energization to the armature coil 21 of each phase is not changed according to the rotary position of the magnet rotor 23, the armature coil 21 is energized in the first and second non-rotary patterns which were established previously. In the first non-rotary pattern, the energization period is established in such a manner as to restrict over-heat of the armature coil 21. In the second non-rotary pattern, it is established so that the energization may not continue for a long period but the energization and un-energizing may be repeated in a short period. Thereby, the heat generation value of the armature coil 21 is restricted due to the continuous energization of the armature coil 21 of a specified phase. And it becomes possible to avoid that the armature coil 21 receives breakage with the heat.
While the over-heat is restricted, the armature coil effectively generates heat by energizing the armature coil 21 for a predetermined period in the first nonrotary pattern. For this reason, the fuel pump 11 can be warmed effectively and it becomes possible to cancel the locked position due to freezing as that result.
Moreover, the magnet rotor 23 can be attracted toward the stator 19 by energizing the armature coil 21 of the predetermined phase. And the magnet

rotor 23 moves toward the stator 19 slightly due to a clearance produced between the shaft 24 and bearings 27, 29. Therefore, it becomes possible to vibrate the magnet rotor 23 and the impeller 18 in a diameter direction by switching each of the armature coils 21 between energization and un-energization. The dust disposed between the magnet rotor 23 and the stator 19 exists being compressed in a diameter direction. But it becomes possible to remove the dust from between the magnet rotor 23 and the stators 19 by vibrating the magnet rotor 23 in the diameter direction.
It becomes possible to vibrate the magnet rotor 23 and the impeller 18 continuously in the diameter direction by energizing the armature coil 21 in a pattern like the second non-rotary pattern in which the energization and the un-energizing is repeated in a short period. Thereby, it is easy to cancel the motor locking condition due to the dust. Moreover, the frequency of the change waveform of energization and un-energization in the second non-rotary pattern is established in such a manner as to be equal to the natural frequency of the magnet rotor 23. Since the magnet rotor 23 resonates by this, the amplitude of vibration can be increased and it becomes easier to cancel the motor locking condition. Besides, it may be established so that the frequency of the change waveform of energization and un-energization in the second non-rotary pattern may become equal to the aliquot of the natural frequency of the magnet rotor 23. Also by this, since the rotor 23 resonates in a high frequency component of the change waveform of energization and un-energization of the second non-rotary pattern, the same operation advantage can be obtained. .
According to this embodiment, the duration of the switching state was measured, and when the duration is beyond specified time, it is determined that it is in the motor locking condition. Thereby, determination of a motor locking condition is attained simply.

According to this embodiment, even if it repeats energization "n nax" times for a specified period by first and the second no-rotary pattern, when the motor locking condition is not canceled, a warning is performed to the user by turning ON the lamp. Thereby, the user can be informed of a possibility that faults other than the motor locking condition have occurred in the fuel pump.
When the fuel pump 11 is placed under low temperature environment after the fuel pump 11 stopped, bearing of the shaft 24 of the magnet rotor 23 freezes, and it falls into the motor locking condition. In this embodiment, when the specified time "T* passes after the fuel pump 11 stops, the armature coil 21 is energized in the first non-rotary pattern for a specified period. Thereby, the fuel pump 11 can be warmed and it can suppress that bearing of the shaft 24 of the magnet rotor 23 freezes. And it becomes possible to suppress the motor locking condition due to freezing as the result.
[A second embodiment]
FIGS. 11 and 12 are charts showing the third and fourth non-rotary patterns in which the magnet rotor 23 is not rotated. The third non-rotary pattern shown in FIG. 11 is used instead of the first non-rotary pattern in the first embodiment. The fourth non-rotary pattern shown in FIG. 12 is used instead of the second non-rotary pattern in the first embodiment.
As shown in FIGS. 11 and 12, in the third and the fourth 4th non-rotary pattern, a specific two phases of three phases are energized in a positive direction and the other phase is energized in a negative direction. Specifically, the U-phase and the V-phase are energized in a positive direction for the specified period, and the W-phase is energized in the negative direction while the U-phase and the V-phase are energized. The third and fourth non-rotary patterns are not patterns in which the MOSFET (U1-W2) of each phase is sequentially switched

according to the rotary position of the magnet rotor 23. Hence, the brushless motor 14 is not driven. When they are energized in the third non-rotary pattern, the armature coil 21 efficiently generates heat as well as in the first non-rotary pattern. Moreover, when they are generated in the fourth non-rotary pattern, the magnet rotor 23 vibrates in the diameter direction as well as in the second nonrotary pattern. Thus, when the third and the fourth non-rotary pattern are used instead of the first and the second non-rotary pattern, the same operation advantage can be obtained as well as the first embodiment.
Since energization is performed to the armature coils 21 of all three-phase circuits when it energizes especially in the third non-rotary pattern, the armature coils 21 of all three-phase can generate heat. For this reason, on the whole, the fuel pump 11 can be warmed efficiently, and it becomes possible to cancel the freezing condition more promptly.
[Third embodiment]
In the above first embodiment, when specified time passed after it is detected that the IG switch 36 is turned OFF, the armature coil 21 is energized in the first non-rotary pattern. In this embodiment, in stead of the above condition, when the temperature detected by the temperature detecting means 37 is under than a prescribed temperature (for example, 0 degree C), the armature coil 21 is energized in the first non-rotary pattern.
Thereby, the peripheral temperature of the fuel pump 11 falls, when a possibility of falling into the motor locking condition by freezing is high, the armature coil 21 generates heat and the fuel pump 11 can be warmed. And it becomes possible to suppress the motor locking condition due to freezing of the baring of the shaft 24.

[Fourth embodiment]
In the above first embodiment, when specified time passed after it is detected that the IG switch 36 is turned OFF, the armature coil 21 is energized in the first non-rotary pattern. In this embodiment, the armature coil 21 is energized in the second non-rotary pattern right after it is detected that the IG switch 36 is turned OFF.
The magnet rotor 23 and the impeller 18 are rotating during rotation of the fuel pump 11. And while they are rotating, the dust currently mixed in the fuel is flipped by the revolution of the magnet rotor 23 or the impeller 18. Therefore, during the revolution of the magnet rotor 23 or the impeller 18, a possibility is low in which the dust is put between the magnet rotor 23 and the stator 19 or introduced into the impeller which cause the motor locking condition. After the fuel pump 11 is stopped, the magnet rotor 23 and the impeller 18 stop immediately, but the fuel continues to flow by inertia. Therefore, immediately after suspending the fuel pump 11, the dust mixed in the fuel easily enters between the magnet rotor 23 and the stator 19, and the motor locking condition is easily generated rather than a situation where the fuel pump 11 is rotating.
In this embodiment, the armature coil 21 is energized in the second nonrotary pattern immediately after the stop of the fuel pump 11. For this reason, it becomes possible to generate a small vibration in the magnet rotor 23 during a period in which there is a high possibility that the motor locking condition may be generated right after the fuel pump 11 is stopped. As a result, it becomes possible to reduce a possibility that the dust is put between the magnet rotor 23 and the stator 19, or the dust is introduced into the impeller 18, which causes the motor locking condition.
Besides, the present invention is not limited to the above-mentioned embodiment, for example, may be performed as follows.

According to the above-mentioned first embodiment, the motor locking condition is detected at the time of start of the fuel pump 11. When the motor locking condition is detected at other than starting time and when the motor locking condition is detected, the energization can be performed in the second non-rotary pattern. Even when foreign matters are introduced into the impeller during its operation to cause the motor locking condition, the motor locking condition can be easily cancelled.
In the first embodiment, when the specified time has passed after the fuel pump 11 stops, the armature coil 21 is energized in the first non-rotary pattern for a specified period. Alternatively, the armature coil 21 can be repeatedly energized every predetermined time "T". Thereby, when the vehicle is parked for several days, it can restrain that it will be in the motor locking condition due to freezing. Moreover, the user may establish the specified time "T" arbitrarily. By establishing the time "T" corresponding to next vehicle activity by the user, the fuel pump 11 is warmed before the vehicle activity, and it becomes possible to cancel the motor locking condition by freezing previously.
In the first embodiment, when the specified time "T" passes after the fuel pump 11 stops, the armature coil 21 is energized in the first non-rotary pattern for a specified period. That is, the energization of the armature coil 21 in the first non-rotary pattern is ended after the specified time has elapsed. However, when the detection temperature by the temperature detecting means 37 turns into more than prescribed temperature, the energization of the armature coil 21 in the first non-rotary pattern can be ended. Since the energization of the armature coil 21 can be performed until the fuel pump 11 fully warms up, it becomes possible to cancel the motor locking condition due to freezing certainly.
Besides, a means for detecting the voltage of the battery mounted in the vehicle is provided, and when battery voltage is below the specified value, the

energization of the armature coil 21 is prohibited or the energizing period and the frequency of energization can be reduced after the stop of the fuel pump 11. It becomes possible to suppress that the battery goes up by energization at the time of the vehicle interdiction.
[Brief Description of the Drawings]
FIG. 1 a cross sectional view showing a fuel pump according to an embodiment of the present invention.
FIG. 2 is a cross sectional view taken along a line l-l of FIG. 1.
FIG. 3 is a chart for explaining the rolling method of the armature coil of the phase.
FIG. 4 is a circuit diagram showing an electric structure of a brushless motor.
FIG. 5 is a chart showing the change pattern of each MOSFET.
FIG. 6 is a time chart showing a rotation pattern of an energized state of each phase.
FIG. 7 is a time chart showing an energized state of each phase in a first non-rotary pattern.
FIG. 8 is a time chart showing an energized state of each phase in a second non-rotary pattern.
FIG. 9 is a flowchart which shows a control procedure for canceling the motor locking condition at the time of start of the fuel pump.
FIG. 10 is a flowchart which shows a control procedure for canceling the motor locking condition after the fuel pump is stopped.
FIG. 11 is a time chart showing an energized state of each phase in a third non-rotary pattern.
FIG. 12 is a time chart showing an energized state of each phase in a

fourth non-rotary pattern.










[Claim 1]
A controller for a fluid pump which includes
a stator having an armature coil of multiphase, and a rotor having a magnetic filed pole confronting to the stator, the controller controlling the fluid pump of brushless type in which the rotor is rotated by sequentially switching an energization of the armature coil of each phase so as to introduce and discharge a fluid, the controller comprising:
an energization means for energizing the armature coil either in a first energizing pattern in which the rotor is rotated by switching the energization of the armature coil of each phase according to a rotational position of the rotor, or in a second energizing pattern in which the armature coil is energized or un-energized in such a manner that the rotor is not rotated.
[Claim 2]
A controller for a fluid pump according to claim 1, wherein
the second energizing pattern is a predetermined pattern in which the
energization and the un-energization are alternately changed along with a
progress of time.
[Claim 3]
A controller for a fluid pump according to claim 1 or 2, wherein
the energization means energizes the armature coil for a specified period
in the second energizing pattern when the fluid pump is started.
[Claim 4]
A controller for a fluid pump according to any one of claims 1 to 3, wherein the energization means energizes the armature coil for a specified period

in the second energizing pattern right after the fluid pump is stopped.
[Claim 5]
A controller for a fluid pump according to any one of claims 1 to 4, wherein the energization means energizes the armature coil for a specified period
in the second energizing pattern when a specified period has passed after the fluid
pump is stopped.
[Claim 6]
A controller for a fluid pump according to any one of claims 1 to 5, wherein the energization means energizes the armature coil for a specified period
in the second energizing pattern every when a specified period has passed after
the fluid pump is stopped.
[Claim 7]
A controller for a fluid pump according to any one of claims 1 to 6, further comprising a temperature detecting means for detect temperature at a vicinity of the fluid pump, wherein
the energization means energizes the armature coil for a specified period in the second energizing pattern when the temperature detected by the temperature detecting means is lower than or equal to a predetermined temperature after the fluid pump is stopped.
[Claim 8]
A controller for a fluid pump according to any one of claims 1 to 7, further comprising a lock detecting means for detecting a lock condition of the fluid pump, wherein

the energization means energizes the armature coil for a specified period in the second energizing pattern when the lock condition of the fluid pump is detected.
[Claim 9]
A controller for a fluid pump according to claim 8, wherein
the lock detecting means determines that the fluid pump is in the lock
condition when an energizing condition of the armature coil of each phase is not
changed and is continued for a specified period.
[Claim 10]
A controller for a fluid pump according to any one of claims 1 to 9, wherein the energization means energizes a specified two phases of the armature
coil and un-energizes the other phase of the armature coil during an energization
period in the second energizing pattern.
[Claim 11]
A controller for a fluid pump according to any one of claims 1 to 10, wherein
the energization means simultaneously energizes the armature coil of all phases during an energization period in the second energizing pattern.
[Claim 12]
A controller for a fluid pump according to any one of claims 1 to 11, wherein
the energization means intermittently energizes the armature coil during an energization period in the second energizing pattern.

[Claim 13]
A controller for a fluid pump according to claim 12, wherein
the energization means switches the energization of the armature coil of
each phase according to the natural frequency of the rotor.


Documents:

2365-CHE-2007 OTHER PATENT DOCUMENT 05-04-2011.pdf

2365-CHE-2007 AMENDED PAGES OF SPECIFICATION 05-04-2011.pdf

2365-CHE-2007 AMENDED CLAIMS 05-04-2011.pdf

2365-CHE-2007 AMENDED CLAIMS 12-05-2011.pdf

2365-CHE-2007 ENGLISH TRANSLATION 05-04-2011.pdf

2365-che-2007 form-1 05-04-2011.pdf

2365-che-2007 form-3 05-04-2011.pdf

2365-che-2007 correspondence others 12-05-2011.pdf

2365-CHE-2007 EXAMINATION REPORT REPLY RECEIVED 05-04-2011.pdf

2365-CHE-2007 CORRESPONDENCE OTHERS 11-10-2010.pdf

2365-CHE-2007 POWER OF ATTORNEY 11-10-2010.pdf

2365-che-2007-abstract.pdf

2365-che-2007-claims.pdf

2365-che-2007-correspondnece-others.pdf

2365-che-2007-description(complete).pdf

2365-che-2007-drawings.pdf

2365-che-2007-form 1.pdf

2365-che-2007-form 18.pdf

2365-che-2007-form 3.pdf

2365-che-2007-form 5.pdf


Patent Number 247807
Indian Patent Application Number 2365/CHE/2007
PG Journal Number 21/2011
Publication Date 27-May-2011
Grant Date 24-May-2011
Date of Filing 18-Oct-2007
Name of Patentee DENSO CORPORATION
Applicant Address 1-1, SHOWA-CHO KARIYA-CITY AICHI-PREF. 448-8661
Inventors:
# Inventor's Name Inventor's Address
1 SATOH, YOSHITAKA C/O DENSO CORPORATION 1-1, SHOWA-CHO KARIYA-CITY AICHI-PREF. 448-8661
2 KURODA, TAKAHIKO C/O DENSO CORPORATION 1-1, SHOWA-CHO KARIYA-CITY AICHI-PREF. 448-8661
3 NAGATA, KIYOSHI C/O DENSO CORPORATION 1-1, SHOWA-CHO KARIYA-CITY AICHI-PREF. 448-8661
PCT International Classification Number F04B 49/06
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 2006-285693 2006-10-20 Japan