Patent Application
20110206539
This application is based on Japanese Patent Applications No. 2010-40702 filed on Feb. 25, 2010, and No. 2010-243236 filed on Oct. 29, 2010, the disclosures of which are incorporated herein by reference.
The present invention relates to a fuel supply system which supplies fuel in a fuel tank to a fuel-consuming apparatus by use of an electric pump.
JP-7-103105A (U.S. Pat. No. 5,355,859) shows a fuel supply system having a pressure sensor provided to a fuel rail and a control circuit controlling electricity supplied to a fuel pump based on an output of the pressure sensor. A plurality of fuel injectors are provided to the fuel rail. In this fuel supply system, a pulse width supplied to the injector has linearity to a fuel injection quantity injected by the injector.
The pressure in the fuel rail has various pressure components. However, the pressure sensor only detects pressure which is linear to the fuel injection quantity.
Further, the fuel pressure supplied from the fuel supply system includes pulsation components which indicate an operation condition of the fuel supply system. For example, the fuel pressure includes high frequency component which indicates an operation condition of an electric pump.
However, in the above fuel supply system, such a pulsation components are not detected by the pressure sensor. In other word, the pressure sensor is not utilized fully enough.
Further, the pressure sensor is provided to the fuel rail. Thus, a pulsation component due to the fuel pump may be attenuated at a position where the pressure sensor is positioned. Furthermore, a pulsation component due to the fuel pump is overlapped with a pulsation component due to the injector. Thus, it is relatively difficult to detect the pulsation component due to the pump.
Besides, in the above conventional system, there is no apparatus which detects a rotation speed of the pump. Thus, no control can be executed based on the rotation speed of the pump.
The present invention is made in view of the above matters, and it is an object of the present invention to provide a fuel supply system which is capable of detecting a rotation speed of a pump.
Another object of the present invention is to provide a fuel supply system which can effectively utilize a pressure sensor provided to the fuel supply system.
Another object of the present invention is to provide a fuel supply system which can detect a rotation speed of a fuel pump by means of a pressure sensor.
The other object of the present invention is to provide a fuel supply system which can detect a pulsation component due to a pump.
According to the present invention, a fuel supply system includes: a fuel pump driven by an electric motor; a sensor detecting a pulsation component included in a pressure of the fuel which is supplied to the fuel-consuming apparatus from the pump; and a speed detection means for detecting a rotation speed of the fuel pump based on a periodic component of the pulsation component detected by the sensor.
The rotation speed of the fuel pump can be indirectly detected.
Other objects, features and advantages of the present invention will become more apparent from the following description made with reference to the accompanying drawings, in which like parts are designated by like reference numbers and in which:
Referring to drawings, embodiments of the present invention will be described hereinafter. In these embodiments, the same parts and components as those in each embodiment are indicated with the same reference numerals and the same descriptions will not be reiterated. Each of following embodiments can be combined suitably.
The engine control system 3 is provided with an electronic control unit (ECU) 31, actuators (SV) 32, and sensors (SS) 33. The ECU 31 includes a microcomputer having a memory media (MEM) 31a. The MEM 31a stores various programs which the computer executes.
The actuators (SV) 32 includes a throttle actuator for adjusting an intake air flow rate, an ignition controller controlling an ignition timing, and an fuel injector 34.
The sensors (SS) 33 include a plurality of sensors which detect a condition of the internal combustion engine 2. For example, the sensors (SS) 33 includes a speed sensor detecting engine speed, and a pressure sensor detecting intake air pressure. Further, the sensors (SS) 33 includes a fuel pressure sensor (PS) 35 detecting a fuel pressure which will be supplied to the fuel injector 34. The fuel pressure sensor (PS) 35 is a pulsation detection means.
The fuel supply system 4 has a fuel tank 41 which stores gasoline. Further, the fuel supply system 4 has an in-tank module 42 accommodated in the fuel tank 41. The in-tank module 42 is provided with a fuel pump (FP) 43, a filter (FL) 44 and a pressure regulator (PR) 45. The pump 43 is an electric pump which pumps up fuel from the fuel tank 41 and pressurizes the pumped fuel. This pressurized fuel is supplied to the injector 34. The filter (FL) 44 is arranged between the fuel pump 43 and the injector 34 to filtrate the fuel flowing through a fuel passage. The pressure regulator 45 is arranged between the fuel pump 43 and the injector 34. The pressure regulator 45 returns excessive fuel to the fuel tank 41 so that the fuel pressure is adjusted to a specified value. A fuel pipe 46a extends from the in-tank module 42 to a fuel rail 46b which distributes the fuel to each injector 34. A fuel supplying system is established from the in-tank module 42 to the injector 34 without any return pipe.
The pump 43 has a motor (MT) 43a and a hydraulic pump unit (PU) 43b. The motor 43a is a direct-current (DC) motor having a brush. The hydraulic pump unit 43b is a regenerative pump driven by the motor 43a.
The in-tank module 42 has a sub tank 42a, a plurality of supporting rods 42b, a pump-assembly 42d, a first pipe 42e, and a second pipe 42f. The sub tank 42a is equipped with a fuel quantity sensor 36 which measures fuel quantity in the fuel tank 41.
The sub tank 42a keeps the full level high around the fuel pump 43 even if the remaining fuel in the tank 41 is decreased. The sub tank 42a can be equipped with a sub-pump (not shown) which pumps up the fuel in the fuel tank 41 and supplies the fuel to the sub tank 42a. The sub-pump is a jet pump which is operated by a return fuel from the pressure regulator 45. The supporting rods 42b connect the lid 41a and the sub tank 42a. The supporting rods 42b is slidably coupled to the sub tank 42a, so that a distance between the lid 41a and the sub tank 42a is adjustable. A spring 42c biases the sub tank 42a toward a bottom of the fuel tank 41. The supporting rods 42b and the spring 42c stably support the sub tank 42a even if the bottom of the fuel tank 41 is deformed.
The first pipe 42e extends from the pump assembly 42d. One end of the first pipe 42e is connected to an outlet of the pump-assembly 42d. The other end of first pipe 42e is connected to an inlet of the pressure sensor 35. Furthermore, one end of the second pipe 42f is connected to an outlet of the pressure sensor 35, and the other end is connected to the outlet pipe 41c. The first and the second pipe 42e, 42f are flexible accordion pipes made of resin material. The fuel discharged from the pump-assembly 42d is supplied to the fuel injector 34 through the first pipe 42e, the pressure sensor 35, the second pipe 42f, and the outlet pipe 41c.
The connector 41b is for connecting the pressure sensor 35, the motor 43a and the fuel quantity sensor 36 with the ECU 31.
The pump 43 has the motor 43a and the hydraulic pump unit 43b. The motor 43a has a stator 43c and a rotor 43d. The rotor 43d is rotatably supported by a shaft 43e. The rotor 43d has a commutator 43f. The commutator 43f is in contact with a brush 43g. The rotor 43d has a coil (not shown). This coil is energized through the brush 43g and the commutator 43f. The motor 43a is controlled by a fuel pump controller (FPC) 47 to drive the hydraulic pump unit 43b.
The hydraulic pump unit 43b is a regeneration pump which is one of non-positive-displacement pumps. The pump unit 43b includes an impeller 43h and a casing 43k which accommodates the impeller 43h. The casing 43k has a suction port (not shown) and a discharge port (not shown). The impeller 43h is driven by the motor 43a. The hydraulic pump unit 43b suctions the fuel in the sub tank 42a through the suction filter 48 and discharges the pumped fuel through a discharge pipe 43m.
The rotation speed of the motor 43a includes a rotational variation component due to a configuration of the motor 43a. For example, the rotation speed of the motor fluctuates due to a variation in contact condition between the brush 43g and the commutator 43f. The contact condition between the brush 43g and the commutator 43f periodically changes in synchronization with a rotation of the rotor 43d. Thus, the rotational variation component synchronizes with the rotation of the rotor 43d. The operation of the pump unit 43b is also fluctuated due to the rotational variation component. As a result, the fuel pressure discharged from the pump unit 43b also has pulsation components corresponding to the rotational variation component.
Further, the fuel pressure pressurized by the pump unit 43b includes pulsation components due to a configuration thereof. The pulsation components synchronize with the rotation of the pump unit 43b. For example, the fuel pressure includes the pulsation components due to a plurality of channels formed on the impeller 43h and a communication condition between the suction port and the discharge port.
Thus, the fuel pressure pressurized by the pump unit 43b includes the pulsation components due to the configuration of the fuel pump 43. These pulsation components include the pulsation components due to a configuration of the motor 43a and the pulsation component due to a configuration of the pump unit 43b.
A resin housing 44a of the filter 44 is utilized as a frame of the pump-assembly 42d. The pump 43 and the pressure regulator 45 are fixed on the housing 44a. The housing 44a is fixed on the sub tank 42a. The housing 44a is formed cylindrical or C-shaped. The housing 44a is comprised of an inner housing 44b and an outer housing 44c. The inner housing 44b defines a fuel pump chamber in which the fuel pump 43 is held. An inlet pipe 44d is formed at upper end of the inner housing 44b. The inlet pipe 44d protrudes inward. The discharge pipe 43m of the fuel pump 43 is inserted into the inlet pipe 44d. An O-ring 42g and a spacer 42h are arranged between the inlet pipe 44d and the discharge pipe 43m.
The lower ends of the inner housing 44b and the outer housing 44c are closed by a bottom plate 44e. A filter chamber is defined between the inner housing 44b and the outer housing 44c. A filter element 44f is accommodated in the filter chamber. The filter element 44f filtrates the fuel flowing through the housing 44a. An upper open end of the outer housing 44c is closed by a cover 44g. The outer housing 44c and the cover 44g are liquid-tightly connected with each other by welding. An upstream gallery 44h is defined upstream of the filter element 44f. A downstream gallery 44k is defined downstream of the filter element 44f.
A cylindrical portion 44m for accommodating the pressure regulator 45 therein and the outlet pipe 44n are formed on a side wall of the housing 44a. A control gallery 44p and a return gallery 44r are defined in the cylindrical portion 44m. O-rings 42k, 42m and a spacer 42n are disposed between the cylindrical portion 44m and the pressure regulator 45. A control gallery 44p communicates with the downstream gallery 44k. The control gallery 44p communicates with an outlet passage 44s defined by the outlet pipe 44n. A return gallery 44r communicates with the sub tank 42a through a sub-pump (not shown).
The housing 44a defines a fuel passage through the inlet pipe 44d, the upstream gallery 44h, the filter element 44f, the downstream gallery 44k, the control gallery 44p, and the outlet passage 44s in this series.
The pressure regulator 45 returns the fuel from the control gallery 44p to the return gallery 44r in such a manner that the pressure in the control gallery 44p is maintained at a predetermined value. The pressure in the control gallery 44p and passages communicating therewith are kept at the predetermined value.
As shown in
Further, since the pressure sensor 35 is provided between the first pipe 42e and the second pipe 42f, the pressure sensor 35 can be installed to even a conventional pump assembly without any difficulties.
Still further, since the pressure sensor 35 is provided in the in-tank module 42, the connector 41b for the fuel pump 43 can be utilized for the pressure sensor 35. The shape of the fuel tank 41 and the lid 41a depends on a vehicle on which the fuel tank 41 is mounted. However, since the pressure sensor 35 is provided in the in-tank module 42, its configuration is common to plurality kinds of vehicles.
The pressure sensor 35 can be provided without any restriction of the shape of lid 41a.
Referring back to
The FPC 47 includes a plurality of modules. A speed detection module (DET) 47b, which corresponds to a speed detection means, extracts a periodic pulsation component due to the configuration of the fuel pump 43 and detects the rotation speed Np of the motor 43a based on the extracted pulsation component. A control module (FC) 47c controls the rotation speed Np in such a manner that the pressure Pf detected by the pressure sensor 35 agrees with the target pressure. The control module 47c includes a feedforward control module (FFC) 47d which feedforward controls the rotation speed of the motor 43a so that the pressure Pf is maintained at the target pressure. A diagnosis-module (DIG) 47e outputs the rotation speed Np detected by the speed detection module (DET) 47b in response to a diagnosis-signal which requires an output of diagnosis information.
Np=1/TM=1/2×DT
The pulsations include a plurality of components of which cycle TP is shorter than the cycle TM. These short period components can be, eliminated by filtering process.
In step 111, the computer determines whether the variation DPf is less than a specified value Kth. When the variation DPf is not less than the value Kth, the computer determines that the fuel pump 43 is in a transitional operation condition. For example, the fuel pump 43 has been just started. Thus, when the answer is NO in step 111, the rotation speed Np is not computed. That is, immediately after the fuel pump 43 is started, a computation of the rotation speed Np is prohibited, so that an erroneous computation of the rotation speed Np can be avoided.
When the answer is YES in step 111, the procedure proceeds to step 112 in which the computer determines whether the variation DPf is turned from a positive value (+) to a negative value (−). That is, it is determined whether the increase in pressure Pf(i) is turned to the decrease in pressure Pf(i). In other words, a peak of the pressure Pf(i) is detected in step 112. When the answer is YES in step 112, the procedure proceeds to step 113. In step 113, a timing at which the peak is detected is stored as a first timing T1.
When the answer is NO in step 112, the procedure proceeds to step 114. In step 114, the computer determines whether the variation DPf is turned from a negative value (−) to a positive value (+). That is, it is determined whether the decreased in pressure Pf(i) is turned to the increased in pressure Pf(i). In other words, a bottom of the pressure Pf(i) is detected in step 114. When the answer is YES in step 114, the procedure proceeds to step 115. In step 115, a timing at which the bottom is detected is stored as a second timing T1.
In step 116, a differential time period between the first timing T1 and the second timing T2 is computed as a differential time DT. In step 117, the computer computes the rotation speed Np of the motor 43a based on the differential timing DT.
Np=f(DT)
This function f(DT) is defined based on the cycle TM and the configuration of the motor 43a, such as a pole number of the stator 43c, a pole number of the rotor 43d, and the pole number of the commutator 43f. The rotation speed Np of the motor 43a computed in step 117 is stored in the memory of the FPC 47.
Np=1/TM=1/2×DT
In step 121, the voltage Vm is computed based on the pressure Pf detected by the pressure sensor 35 and the rotation speed Np of the motor 43a. The voltage Vm is computed based on a feedback amount FB(Pf) and a feedforward amount FF(Np). The feedback amount FB(Pf) is computed based on the pressure Pf, and the feedforward amount FF(Np) is computed based on the rotation speed Np. The feedback amount FB(Pf) is computed by feedback control, such as PI control and the PID control. The feedforward amount FF(Np) is computed based on the rotation speed Np in order to obtain higher response than the feedback amount FB(Pf). The voltage Vm may be computed based on a basic voltage Vbase, the feedback amount FB(Pf), the feedforward amount FF(Np), and a correction amount Vcor. The correction amount Vcor may include voltage Vrel for canceling a locking condition of the fuel pump 43. The locking condition occurs when the fuel pump 43 suctions a foreign matter. Also, the correction amount Vcor may include voltage Vmech for compensating an increase in mechanical load of the fuel pump 43. In step 122, the computed voltage Vm is applied to the motor 43a.
In step 131, the computer determines whether the diagnosis-signal is inputted. When the answer is YES, the procedure proceeds to step 132 in which the rotation speed Np computed in the speed computing processing 110 is outputted. This rotation speed Np is indicated on a display (not shown) provided to the internal combustion engine system 1 or a diagnosis device (not shown). Thereby, it is diagnosed whether the motor 43a is normally operated.
According to the embodiment described above, the rotation speed Np of the fuel pump 43 is obtained based on the fuel pressure Pf detected by the pressure sensor 35. The rotation speed Np of the fuel pump 43 can be indirectly detected. Further, the pressure sensor 35 is utilized for controlling the fuel pressure. Thus, the pressure sensor 35 is utilized fully enough. Further, the pressure sensor 35 can detect the pulsation due to the fuel pump 43 while reducing the pulsation components due to the injector 34.
The pump assembly 242d is provided with a pressure sensor 235. The pressure sensor 235 is connected to a housing 244a in such a manner as to detect fuel pressure in the housing 244a.
Specifically, the pressure sensor 235 is fixed on a cover 244g to be exposed in the upstream gallery 44h. The pressure sensor 235 confronts an opening end of the discharge pipe 43m.
The pressure sensor 235 detects fuel pressure in the upstream gallery 44h between the fuel pump 43 and the filter element 44f. More specifically, the pressure sensor 235 detects pressure of fuel which discharged from the discharge pipe 43m immediately after the fuel is discharged therefrom.
According to the present embodiment, the pressure sensor 235 can be arranged at a position where an attenuation of the pulsation component due to the fuel pump 43 is relatively small.
The pressure sensor 335 detects fuel pressure Pf flowing through the fuel pipe 46a. Also in this embodiment, the speed detection module 47b detects the rotation speed Np of the motor 43a based on the pulsation component of the fuel pressure Pf.
The vibration pickup sensor 436 detects vibration of the fuel pipe 46a. The vibration of the fuel pipe 46a includes a pulsation component due to a pulsation of the fuel pressure Pf in the fuel pipe 46a. Thus, the vibration pickup sensor 436 can output a detection signal corresponding to a pulsation component due to the configuration of the motor 43a. According to the present embodiment, the speed detection module 447b detects the rotation speed Np of the motor 43a based on the periodic pulsation component included in the vibration Vb detected by the vibration pickup sensor 436.
In step 501, the computer determines whether the pressure Pf detected by the pressure sensor 35 is less than or equal to a specified threshold pressure Pth. When the answer is YES in step 501, the procedure proceeds to step 502. When the answer is NO, the procedure proceeds to step 503. In step 502, the FPC 47 stores information that the fuel supply parts other than the fuel pump 43 have malfunctions.
In step 503, the computer determines whether the rotation speed Np detected by the speed detection module 47b is less than or equal to a specified threshold Nth. When the answer is YES in step 503, the procedure proceeds to step 504. When the answer is NO, the procedure proceeds to step 505. In step 504, the computer determines that the fuel pump 43 has malfunctions. The FPC 47 stores information that the fuel pump 43 has malfunctions. The above processing corresponds to a determination means for determining whether the fuel pump 43 has a malfunction.
In step 505, the computer determines that the fuel supply parts including the fuel pump 43 have no malfunction. The FPC 47 stores information that the fuel supply parts including the fuel pump 43 have no malfunction.
According to the present embodiment, the computer determines whether the fuel supply parts including the fuel pump 43 have malfunctions based on the pressure information detected by the pressure sensor 35. Furthermore, based on the pressure information, the computer can distinguish between the malfunction of the fuel pump 43 and the malfunction of other fuel supply parts.
In step 601, the computer computes a differential speed DNp between the current speed Np(i) and the previous speed Np(i−1). The differential speed DNp corresponds to a variation in rotation speed Np. In step 602, the computer determines whether the rotation speed Np is decreased by a specified value. Specifically, the computer determines whether the differential speed DNp is less than a specified threshold “−DNth”. If the differential speed DNp is less than “−DNp”, it is conceivable that the fuel pump 43 has some malfunctions. For example, the fuel pump 43 suctions foreign matters to be locked up. When the answer is YES in step 602, the procedure proceeds to step 603 in which the computer determines that the fuel pump 43 is locked up. This information is stored in the FPC 47. When the answer is NO in step 602, the procedure proceeds to step 604.
In step 604, the computer determines whether a feedback amount FB(Pf) computed based on the pressure Pf is greater than a specified feedback threshold FBth. When the pressure Pf does not come close to the target pressure, the feedback amount FB(Pf) is set larger. Thus, when the feedback amount FB(Pf) is greater than the feedback threshold FBth, it is conceivable that the fuel pump 43 does not perform sufficiently due to its malfunction such as a lock-up. When the answer is YES in step 604, the procedure proceeds to step 603. When the answer is NO in step 604, the procedure proceeds to step 605. In step 605, the computer determines that the fuel pump 43 is normal and its information is stored in the FPC 47.
The malfunctions of the fuel pump lock-up due to foreign matters can be corrected by increasing electricity supplied to the motor 43a. For example, mechanical malfunctions due to foreign matters contained in the fuel can be corrected by increasing a generating torque of the motor 43a. Also, electric malfunctions due to insulating material can be corrected by increasing the electricity supplied to the motor 43a. In the motor control processing 700, the voltage Vm applied to the motor 43a is temporarily increased. The voltage Vm is increased by specified pulse voltage Vpu for releasing the lock-up.
Furthermore, the mechanical load in the fuel pump 43 may increase continuously. For example, if foreign matters remain in the fuel pump 43 over the long time period, the discharge capacity of the fuel pump 43 has been deteriorated for a long time period. Also, when the parts of the fuel pump 43 are deteriorated with age, the discharge capacity of the fuel pump 43 is deteriorated. In the motor control processing 700, the voltage Vm applied to the motor 43a is continuously increased in order to keep the initial discharge capacity against an increase in mechanical load. In the present embodiment, the voltage Vm is increased by specified stationary voltage Vsta against the increase in mechanical load.
In step 701, the computer determines whether the fuel pump 43 is locked up. This determination is based on the determination result in step 603. When the answer is YES in step 701, the procedure proceeds to step 702. When the answer is NO in step 701, the procedure proceeds to step 709. In step 702, the computer determines whether it is a first processing after it is determined that the fuel pump 43 is locked up in step 603. When the answer is YES in step 702, the procedure proceeds to step 703. When the answer is NO in step 702, the procedure proceeds to step 704. In step 703, the stationary voltage Vsta is defined as a voltage Vmech for mechanical load. The stationary voltage Vsta is established to maintain the initial discharge capacity against the increase in mechanical load. The process in step 703 corresponds to a driving force assist means for constantly increasing the electric power supplied to the fuel pump 43. In step 704, the pulse voltage Vpul is defined as the voltage Vrel for releasing the lock-up of the fuel pump 43.
In step 705, the computer determines whether an elapsed time Time(Lock) after the lock determination in step 603 exceeds a specified threshold time Tth. When the answer is YES in step 705, the procedure proceeds to step 706. When the answer is NO, the procedure proceeds to step 707. In step 706, the voltage Vrel is set to zero. That is, when the threshold time Tth has elapsed after the lock-up of the fuel pump is detected in step 603, the voltage Vrel is set to zero. Thereby, the voltage Vrel is applied to the motor 43a as pulse-form voltage. Therefore, the processings from step 704 to step 706 correspond to a malfunction correction means for temporarily increasing the electric power supplied to the fuel pump 43.
In step 707, the voltage Vm applied to the motor 43a is corrected based on the voltage Vrel and the voltage Vmech. Specifically, the voltage Vrel and the voltage Vmech are added to the voltage Vm which is computed based on the feedback amount FB(Pf). In step 708, the voltage Vm is applied to the motor 43a. In step 709, the voltage Vmech is set to zero.
When the lock-up of the fuel pump 43 is detected at a timing t1, the pulse voltage Vpul and the stationary voltage Vsta are established in steps 701-708. The voltage Vm applied to the motor 43a is increased. Thereby, the motor 43a can generate the torque necessary for eliminating any malfunctions. Then, when the threshold time Tth has passed, the pulse voltage Vpul is canceled. Also, when the lock-up of the fuel pump 43 is released before the threshold time Tth has passed, the pulse voltage Vpul is canceled. As a result, the voltage Vm is reduced. In
When the lock-up of the fuel pump 43 is released at a timing t3, the stationary voltage Vsta is also canceled. Then, the voltage Vm is controlled based on at least the feedback amount FB(Pf). As shown by broken lines in
According to the present embodiment, the computer determines whether the fuel pump 43 is locked up based on the pressure Pf detected by the pressure sensor 35. Since the rotation speed Np of the fuel pump 43 is detected based on the pressure Pf, it is accurately determined whether the fuel pump 43 is locked up. In addition, the correction voltage Vrel can be applied to the motor 43a in order to release the lock-up of the fuel pump 43. Further, when the mechanical load of the fuel pump 43 is increased, the correction voltage Vmech can be applied to the motor 43a against the increased mechanical load. Thus, even if the mechanical load of the fuel pump 43 is increased, it is restricted that the discharge capacity of the fuel pump 43 is deteriorated.
The preferred embodiment is described above. The present invention is not limited to the above embodiment.
The motor 43a may be a brushless motor. The hydraulic pump unit 43b may be a trochoid gear pump which is one of positive-displacement pumps.
In the above embodiments, the rotation speed Np of the fuel pump 43 is detected based on the pulsation components due to the configuration of the motor 43a. The rotation speed Np may be detected based on the pulsation components due to the configuration of the pump unit 43b. Alternatively, the rotation speed Np can be detected based on synthesized components of the pulsation components due to the configurations of the motor 43a and the pump unit 43b.
The peak points or the bottom points of the pulsation components are detected and then the cycle can be obtained from an interval between adjacent peak points or adjacent bottom points.
By executing the discrete Fourier transformation based on a plurality of sampling values of the fuel pressure, the rotation speed Np can be computed.
The fuel pump controller (FPC) 47 can be configured by software, hardware or a combination thereof. For example, the FPC 47 can be configured by an analog circuit.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2010-40702 | Feb 2010 | JP | national |
| 2010-243236 | Oct 2010 | JP | national |
