U.S. patent application number 14/221593 was filed with the patent office on 2014-10-02 for control device for electric pump.
This patent application is currently assigned to TOYOTA JIDOSHA KABUSHIKI KAISHA. The applicant listed for this patent is Mitsuaki HIGA, Noritaka TAKUDA, Masashi YOSHIMI. Invention is credited to Mitsuaki HIGA, Noritaka TAKUDA, Masashi YOSHIMI.
Application Number | 20140294600 14/221593 |
Document ID | / |
Family ID | 51596155 |
Filed Date | 2014-10-02 |
United States Patent
Application |
20140294600 |
Kind Code |
A1 |
TAKUDA; Noritaka ; et
al. |
October 2, 2014 |
CONTROL DEVICE FOR ELECTRIC PUMP
Abstract
A control device for an electric pump, the electric pump pumping
a cooling medium, the control device includes a controller
configured to determine a presence of an abnormality in the
electric pump when a temperature of the cooling medium is higher
than a threshold value and the electric pump is locked. The
threshold value being predetermined as a temperature that is higher
than a freezing point of the cooling medium.
Inventors: |
TAKUDA; Noritaka;
(Toyota-shi, JP) ; HIGA; Mitsuaki; (Toyota-shi,
JP) ; YOSHIMI; Masashi; (Toyota-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TAKUDA; Noritaka
HIGA; Mitsuaki
YOSHIMI; Masashi |
Toyota-shi
Toyota-shi
Toyota-shi |
|
JP
JP
JP |
|
|
Assignee: |
TOYOTA JIDOSHA KABUSHIKI
KAISHA
Toyota-shi
JP
|
Family ID: |
51596155 |
Appl. No.: |
14/221593 |
Filed: |
March 21, 2014 |
Current U.S.
Class: |
417/32 |
Current CPC
Class: |
F04B 17/03 20130101;
F04B 2205/11 20130101; F04B 49/06 20130101; F04B 49/10 20130101;
F04B 2201/0801 20130101 |
Class at
Publication: |
417/32 |
International
Class: |
F04B 49/06 20060101
F04B049/06 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 26, 2013 |
JP |
2013-063910 |
Claims
1. A control device for an electric pump, the electric pump pumping
a cooling medium, the control device comprising: a controller
configured to determine a presence of an abnormality in the
electric pump when a temperature of the cooling medium is higher
than a threshold value and the electric pump is locked, the
threshold value being predetermined as a temperature that is higher
than a freezing point of the cooling medium.
2. The control device according to claim 1, wherein the controller
is configured to intermittently drive the electric pump when the
temperature of the cooling medium is equal to or lower than the
threshold value and the electric pump is locked.
3. The control device according to claim 2, wherein the controller
is configured to stop the intermittent driving of the electric
pump, when the electric pump rotates after the electric pump is
locked in a condition in which the temperature of the cooling
medium is equal to or lower than the threshold value.
Description
INCORPORATION BY REFERENCE
[0001] The disclosure of Japanese Patent Application No.
2013-063910 filed on Mar. 26, 2013 including the specification,
drawings and abstract is incorporated herein by reference in its
entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates to a control device for an electric
pump, and in particular to determine a presence of an abnormality
in the electric pump.
[0004] 2. Description of Related Art
[0005] Hybrid vehicles and electric vehicles are able to run using
an electric motor, in place of an engine, as a drive source. In a
vehicle of this type, driving force of the engine may not be used
for driving a water pump for circulating cooling water. Therefore,
an electric water pump is used. When the electric water pump is
locked, namely, when the electric water pump does not rotate even
if it is energized, the water pump cannot circulate the cooling
water. Therefore, the water pump needs to be repaired.
[0006] In order to inform the driver that the electric water pump
needs to be repaired, it is necessary to detect that the electric
water pump is locked.
[0007] As one method of detecting locking of a pump, it is
determined that a brushless motor of a fuel pump is in a locked
state if electric current is kept applied to the brushless motor
for a given period of time or longer, as described in Japanese
Patent Application Publication No. 2008-101561 (JP 2008-101561
A).
SUMMARY OF THE INVENTION
[0008] However, even if there is an absence of abnormality in the
electric pump itself, the electric pump may be locked if a cooling
medium to be pumped from the electric pump is freezing. In this
case, it may be erroneously determined that the electric pump is
abnormal.
[0009] The present invention provides improved accuracy with which
a presence of an abnormality in an electric pump is determined.
[0010] A control device for an electric pump which pumps a cooling
medium according to one aspect of the invention, the control device
includes a controller configured to determine a presence of an
abnormality in the electric pump when a temperature of the cooling
medium is higher than a threshold value and the electric pump is
locked. The threshold value being predetermined as a temperature
that is higher than a freezing point of the cooling medium. Thus, a
presence of an abnormality, i.e., locking of the electric pump, can
be determined under a condition that the temperature of the cooling
medium is higher than the threshold value, and the cooling medium
is not freezing. Therefore, locking of the electric pump due to
freezing of the cooling medium will not be erroneously determined
as an abnormality. Thus, the accuracy with which a presence of an
abnormality of the electric pump is detected can be improved.
[0011] In the control device according to the above aspect of the
invention, the controller may be configured to intermittently drive
the electric pump when the temperature of the cooling medium is
equal to or lower than the threshold value and the electric pump is
locked. Thus, it may be possible to remove the freezing cooling
medium or foreign matters with which the electric pump is clogged,
while curbing undue driving of the electric pump.
[0012] In the control device as described above, the controller may
be configured to stop the intermittent driving of the electric
pump, when the electric pump rotates after the electric pump is
locked in a condition in which the temperature of the cooling
medium is equal to or lower than the threshold value. As a result,
the electric pump is continuously driven, so that the coolant
medium can be continuously supplied to a supply destination of the
cooling medium.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Features, advantages, and technical and industrial
significance of exemplary embodiments of the invention will be
described below with reference to the accompanying drawings, in
which like numerals denote like elements, and wherein:
[0014] FIG. 1 is a schematic view of a vehicle; and
[0015] FIG. 2 is a flowchart illustrating a control routine
executed by an ECU.
DETAILED DESCRIPTION OF EMBODIMENTS
[0016] One embodiment of the invention will be described with
reference to the drawings. In the following description, the same
reference numerals are assigned to the same components. These
components have the same names and functions. Accordingly, these
components will not be repeatedly described in detail.
[0017] Referring to FIG. 1, an engine 100, a first motor-generator
110, a second motor-generator 120, a power split device 130, a
speed reducer 140, and a battery 150 are installed on the vehicle.
While a hybrid vehicle will be explained as one example in the
following description, a vehicle called "electric vehicle with a
range extender" or "range extended electric vehicle" may be used.
Also, a vehicle on which only the engine 100 is installed as a
drive source, or an electric vehicle on which only an electric
motor is installed as a drive source may be used.
[0018] The engine 100, first motor-generator 110, second
motor-generator 120, and the battery 150 are controlled by an ECU
(Electronic Control Unit) 170. The ECU 170 may be divided into two
or more ECUs.
[0019] As one example, when a start switch 171 is turned on by the
user, the ECU 170 controls a system including the engine 100, first
motor-generator 110, second motor-generator 120, etc., so as to
enable the vehicle to run.
[0020] The vehicle runs with driving force from at least one of the
engine 100 and the second motor-generator 120. Namely, one or both
of the engine 100 and the second motor-generator 120 is/are
automatically selected as a drive source(s), according to operating
conditions.
[0021] In the case where the accelerator operation amount is small,
and the case where the vehicle speed is low, for example, the
vehicle runs using only the second motor-generator as a drive
source. In this case, the engine 100 is stopped. In some cases,
however, the engine 100 may be driven for generation of electric
power, for example.
[0022] In the case where the accelerator operation amount is large,
the case where the vehicle speed is high, and the case where the
remaining capacity (SOC: State Of Charge) of the battery 150 is
small, for example, the engine 100 is driven. In this case, the
hybrid vehicle runs using only the engine 100, or both of the
engine 100 and the second motor-generator 120, as a drive source or
sources.
[0023] The engine 100 may be used solely for the purpose of
generating electric power, without being used as a drive source for
running the vehicle. Namely, the hybrid vehicle may be a series
hybrid vehicle.
[0024] The engine 100 is an internal combustion engine. In
operation, an air-fuel mixture is burned in a combustion chamber,
so that a crankshaft as an output shaft of the engine is
rotated.
[0025] The engine 100, first motor-generator 110, and the second
motor-generator 120 are connected via the power split device 130.
Power generated by the engine 100 is divided by the power split
device 130 to be distributed to two pathways. More specifically,
power is transmitted through one of the two pathways to front
wheels 160 via the speed reducer 140 so as to drive the front
wheels 160, and is transmitted through the other pathway so as to
drive the first motor-generator 110.
[0026] The first motor-generator 110 is a three-phase AC rotary
electric machine having a U-phase coil, a V-phase coil, and a
W-phase coil. The first motor-generator 110 generates electric
power using the power of the engine 100 divided by the power split
device 130. Namely, the first motor-generator 110 functions as a
generator. The electric power generated by the first
motor-generator 110 is used for different purposes, depending on
running conditions of the vehicle, and the state of the remaining
capacity of the battery 150. For example, during normal running,
electric power generated by the first motor-generator 110 is used
as it is for driving the second motor-generator 120. On the other
hand, when the SOC of the battery 150 is lower than a predetermined
value, electric power generated by the first motor-generator 110 is
converted from AC power to DC power by an inverter (which will be
described later). Then, the electric power is stored in the battery
150 after the voltage is adjusted by a converter.
[0027] When the first motor-generator 110 operates as a generator,
the first motor-generator 110 generates negative torque. The
negative torque mentioned herein means torque that leads to a load
of the engine 100. When the first motor-generator 110 is supplied
with electric power and operates as a motor, the first
motor-generator 110 generates positive torque. The positive torque
mentioned herein means torque that does not lead to a load of the
engine 100, namely, torque that assists in rotation of the engine
100. The above explanation also applies to the second
motor-generator 120.
[0028] The second motor-generator 120 is a three-phase AC rotary
electric machine having a U-phase coil, a V-phase coil and a
W-phase coil. The second motor-generator 120 is driven with at
least one of electric power stored in the battery 150 and electric
power generated by the first motor-generator 110.
[0029] The driving force of the second motor-generator 120 is
transmitted to the front wheels 160 via the speed reducer 140. As a
result, the second motor-generator 120 assists the engine 100, or
the vehicle runs using the driving force from the second
motor-generator 120. In this connection, rear wheels may be driven
in place of or in addition to the front wheels 160.
[0030] During regenerative braking of the hybrid vehicle, the
second motor-generator 120 is driven by the front wheels 160 via
the speed reducer 140, and the second motor-generator 120 operates
as a generator. Thus, the second motor-generator 120 operates as a
regenerative brake that converts braking energy into electric
power. The electric power generated by the second motor-generator
120 is stored in the battery 150.
[0031] The power split device 130 is in the form of a planetary
gear set including a sun gear, a pinion gear, a carrier, and a ring
gear. The pinion gear engages with the sun gear and the ring gear.
The carrier supports the pinion gear such that the pinion gear can
rotate about itself. The sun gear is coupled to a rotary shaft of
the first motor-generator 110. The carrier is coupled to the
crankshaft of the engine 100. The ring gear is coupled to a rotary
shaft of the second motor-generator 120 and the speed reducer
140.
[0032] The engine 100, first motor-generator 110, and the second
motor-generator 120 are coupled to each other via the power split
device 130 in the form of the planetary gear set, so that the
rotational speeds of the engine 100, first motor-generator 110, and
the second motor-generator 120 are related to be connected by a
straight line in a nomographic chart.
[0033] In this embodiment, an electric water pump 104 is provided
as a cooling device for cooling the engine 100. The electric water
pump 104 pumps cooling water, as a "cooling medium", so that the
cooling water circulates in the engine 100. The temperature of the
cooling water of the engine 100 is detected by a temperature sensor
106, and the ECU 170 receives the output of the temperature sensor
106. The ECU 170, as an "controller", has the function of
controlling the electric water pump 104.
[0034] When the electric water pump 104 is locked, in a condition
where the temperature of the cooling water (which will also be
referred to as "water temperature") is lower than a threshold value
that is predetermined by a developer so as to be higher than the
freezing point of the cooling water, the ECU 170 provisionally
determines a presence of an abnormality in the electric water pump
104. If the presence of the abnormality is provisionally
determined, the electric water pump 104 is intermittently driven by
the ECU 170 at given intervals. Namely, electric current is
intermittently passed through an electric motor of the electric
water pump 104.
[0035] General technologies may be utilized for determining whether
the electric water pump 104 is locked or not. For example, it is
determined whether the electric water pump 104 is locked, depending
on whether lock current is detected, or depending on whether
application of electric current to a brushless motor of the
electric water pump 104 is continued for a given period of time.
These technologies will not be described in detail.
[0036] If the electric water pump 104 rotates after the ECU 170
provisionally determines the presence of the abnormality in the
electric water pump 104, the intermittent driving of the electric
water pump 104 is stopped, and the electric water pump 104 is
continuously driven. As one example, if locking of the electric
water pump 104 is not detected when the electric water pump 104 is
driven (i.e., when electric current flows through the electric
water pump 104), it is determined that the electric water pump 104
is rotating.
[0037] If, on the other hand, the water temperature is higher than
the threshold value, and the electric water pump 104 is locked, the
ECU. 170 determines a presence of an abnormality in the electric
water pump 104.
[0038] Referring to FIG. 2, a control routine executed by the ECU
170 in this embodiment will be described. The control routine as
described below is repeatedly executed at given intervals. The
control routine as described below may be implemented by software,
hardware, or through cooperation of software and hardware.
[0039] In step S100, it is determined whether the electric water
pump 104 is locked. If the electric water pump 104 is locked (YES
in step S100), it is determined in step S102 whether the water
temperature is higher than the threshold value. As described above,
the threshold value is higher than the freezing point of the
cooling water. In this step S102, an estimated value of the water
temperature may be used, in place of the water temperature detected
using the temperature sensor 106.
[0040] If the water temperature is higher than the threshold value
(YES in step S102), it is determined in step S104 that the electric
water pump 104 is abnormal.
[0041] If, on the other hand, the water temperature is equal to or
lower than the threshold value (NO in step S102), it is
provisionally determined in step S106 that the electric water pump
104 is abnormal. Then, in step S108, the electric water pump 104 is
intermittently driven at given intervals. Namely, electric current
is intermittently passed through the electric water pump 104 at
given intervals.
[0042] If it is determined that the electric water pump 104 is not
locked (NO in step S100), it is determined in step S110 whether it
is provisionally determined that the electric water pump 104 is
abnormal.
[0043] If it is provisionally determined that the electric water
pump 104 is abnormal (YES in step S110), it may be considered that
the electric water pump 104 has been temporarily locked. In this
case, in step S112, the intermittent driving of the electric water
pump 104 is stopped. Accordingly, electric current is continuously
passed through the electric water pump 104.
[0044] The embodiment disclosed herein should be considered as
being exemplary in all respects and not restrictive. The scope of
the invention is defined by the appended claims, rather than the
above description, and is intended to include all changes within
the range of the claims and equivalents thereof.
* * * * *