CONTROL DEVICE FOR VEHICLE DRIVE DEVICE
A control device of a vehicle drive device including an electromagnetic valve oil pump sucking and discharging hydraulic oil through ON/OFF operations of an electromagnetic valve, a drive frequency controller for controlling a drive frequency at which the electromagnetic valve is to be turned on/off, a temperature sensor for detecting an oil temperature of the hydraulic oil, and a hydraulic circuit supplied with the hydraulic oil discharged from the electromagnetic valve oil pump, the control device of a vehicle drive device further including a surge absorption circuit absorbing a counter electromotive force generated in the electromagnetic valve oil pump, the drive frequency of operation of the electromagnetic valve oil pump being set lower when the oil temperature is low than when the oil temperature is high.
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The present invention relates to a control device of a vehicle drive device and particularly to control of a drive device including an electromagnetic valve oil pump.
BACKGROUND ARTAn actuator of a vehicle driven by an oil pressure such as a hydraulic clutch is conventionally supplied with hydraulic oil from a mechanical oil pump driven mainly by an engine. It is also proposed to include not only the mechanical oil pump but also an electromagnetic valve oil pump. For example, a pump device described in Patent Document 1 is an example thereof. Patent Document 1 discloses a configuration including an electromagnetic valve oil pump in addition to a mechanical oil pump driven by an engine. For example, when a vehicle is stopped with a shift range maintained in a D-range as in the case of waiting for a traffic light, the engine is automatically stopped and the electromagnetic valve oil pump is driven to supply a proper oil pressure in preparation for the next start so as to enable a prompt start. The electromagnetic valve oil pump of Patent Document 1 has a drive frequency of an electromagnetic valve made variable to enable the supply of the optimum oil pressure regardless of aged deterioration of a vehicle.
PRIOR ART DOCUMENT Patent DocumentPatent Document 1: Japanese Laid-Open Patent Publication No. 2011-69258
SUMMARY OF THE INVENTION Problem to be Solved by the InventionThe electromagnetic valve oil pump applies a current repeatedly turned on and off to an electromagnetic valve to cause a plunger (piston) disposed in a solenoid coil to reciprocate, thereby repeatedly suck and discharge hydraulic oil. This plunger is coupled to a spring biasing the plunger in one direction and, it is known that when the energization of the electromagnetic valve is switched off and the plunger moves in the solenoid coil due to the spring, a surge power (counter electromotive force) is generated in a drive circuit of the electromagnetic valve. Therefore, a surge absorption circuit absorbing this surge power is typically disposed. When a surge absorption power absorbed by the surge absorption circuit becomes large, a circuit scale increases for ensuring heat resistance, resulting in a larger size and higher cost of the surge absorption circuit. Therefore, it is desired to reduce the surge absorption power.
Since the electromagnetic valve oil pump is connected via a valve body etc. to a hydraulic clutch, leakage of the hydraulic oil occurs from the valve body, for example. A leakage amount of the hydraulic oil changes depending on an oil temperature of the hydraulic oil and, for example, the leakage amount becomes larger at higher oil temperature. Since the design is based on a state at the time of high oil temperature associated with a large leakage amount, the electromagnetic valve oil pump is required to have a larger discharge amount. However, a smaller leakage amount at the time of low oil temperature leads to excessive flow rate and oil pressure, resulting in an energy loss. When the oil temperature of the hydraulic oil is low, the surge absorption power becomes large in association with increased viscous resistance of the hydraulic oil and an increased solenoid current flowing through the solenoid coil. Therefore, a large surge absorption circuit is required. In Patent Document 1, no consideration is given to a change in the viscous resistance due to a change in the oil temperature of the hydraulic oil. Therefore, even if consideration is given to the leakage amount of the hydraulic oil, since the design is based on a state at the time of high oil temperature associated with a large leakage amount and the solenoid current becomes large at the time of low oil temperature and therefore increases the surge power, a large-sized surge absorption circuit is required, resulting in a problem of a higher cost.
The present invention was conceived in view of the situations and it is therefore an object of the present invention to provide a control device of a vehicle drive device including an electromagnetic valve oil pump and capable of reducing a size of a surge absorption circuit absorbing a surge generated during operation of the electromagnetic valve oil pump.
Means for Solving the ProblemTo achieve the object, the first aspect of the invention provides a control device of a vehicle drive device including (a) an electromagnetic valve oil pump sucking and discharging hydraulic oil through ON/OFF operations of an electromagnetic valve, a means of controlling a drive frequency at which the electromagnetic valve oil pump is to be turned on/off, a means of detecting an oil temperature of the hydraulic oil, and a hydraulic circuit supplied with the hydraulic oil discharged from the electromagnetic valve oil pump, the control device of a vehicle drive device further including (b) a surge absorption circuit absorbing a counter electromotive force generated in the electromagnetic valve oil pump, (c) the drive frequency of operation of the electromagnetic valve oil pump being set lower when the oil temperature is low than when the oil temperature is high.
Effect of the InventionFor example, if the electromagnetic valve oil pump is operated at a constant drive frequency regardless of an oil temperature and the oil temperature is low, the viscous resistance of the hydraulic oil is large and the solenoid current flowing through the electromagnetic valve oil pump is increased. Therefore, a surge power becomes large and therefore necessitates a surge absorption circuit having a large physical size designed with a large surge absorption power. The leakage amount of the hydraulic oil from the hydraulic circuit becomes smaller as the viscous resistance of the hydraulic oil becomes larger. In other words, the leakage amount of the hydraulic oil from the hydraulic circuit has characteristics that the leakage amount becomes smaller as the oil temperature becomes lower. As a result, when the oil temperature is low, the leakage amount becomes smaller and, therefore, a required flow rate can be ensured even if the discharge flow rate of the electromagnetic valve oil pump is suppressed as compared to when the oil temperature is high. The drive frequency of operation of the electromagnetic valve oil pump is set lower when the oil temperature is low than when the oil temperature is high. This setting makes the drive frequency lower and therefore makes the discharge amount of the electromagnetic valve oil pump smaller when the oil temperature is low; however, since the leakage amount of the hydraulic oil becomes smaller, the required flow rate can be ensured. Since the surge power is proportional to the drive frequency, the surge power becomes small even at the time of low oil temperature and, therefore, the surge absorption circuit can be reduced in size. On the other hand, the leakage amount becomes larger at the time of high oil temperature and, therefore, the drive frequency is made higher to increase the discharge amount of the electromagnetic valve oil pump; however, since the viscous resistance of the hydraulic oil is small at the time of high oil temperature and the solenoid current becomes lower as compared to the time of low temperature, the surge power does not become large. Thus, the surge absorption circuit can be reduced in size.
Preferably, the second aspect of the invention provides the control device of a vehicle drive device recited in the first aspect of the invention, wherein the oil temperature of the hydraulic oil is calculated based on a solenoid current of the electromagnetic valve. As a result, the oil temperature can be detected without using a sensor etc.
Preferably, the third aspect of the invention provides the control device of a vehicle drive device recited in the first aspect of the invention, wherein the drive frequency of the electromagnetic valve oil pump continuously varies depending on the oil temperature. As a result, the frequency is set such that the required flow rate can be ensured depending on the oil temperature, and an extra flow rate and oil pressure can be suppressed to prevent the energy loss.
Preferably, the fourth aspect of the invention provides the control device of a vehicle drive device recited in the first aspect of the invention, wherein the drive frequency of the electromagnetic valve oil pump varies in stages based on a preset threshold value of the oil temperature. As a result, the frequency varies based on the threshold values of the oil temperature and the required flow rate can be ensured while suppressing the surge power.
Preferably, the fifth aspect of the invention provides the control device of a vehicle drive device recited in the first aspect of the invention, wherein the oil temperature of the hydraulic oil is detected by an oil temperature sensor and calculated based on the solenoid current of the electromagnetic valve, wherein the oil temperature is normally detected by the oil temperature sensor, and is calculated based on the solenoid current when the oil temperature is not detected by the oil temperature sensor. As a result, a reliable value of the oil temperature is normally detected by the oil temperature sensor and, even if the oil temperature cannot be detected by the oil temperature sensor, the oil temperature can be calculated based on the solenoid current of the electromagnetic valve, and the optimum drive frequency can be set based on the oil temperature. For example, if the oil temperature is detected only by the oil temperature sensor and the detection by the oil temperature sensor becomes unavailable, the optimum discharge amount of the electromagnetic valve oil pump based on the oil temperature becomes unknown and, therefore, the drive frequency must be made high so as to ensure the discharge amount. Thus, the surge power becomes large, which necessitates corresponding enlargement of the surge absorption circuit. In contrast, since the oil temperature can be calculated based on the solenoid current of the electromagnetic valve, even if the oil temperature cannot be detected by the oil pressure sensor, the oil temperature is calculated based on the solenoid current of the electromagnetic valve so as to set the drive frequency to an optimum value and, therefore, the surge power is suppressed so that the surge absorption circuit is certainly prevented from increasing in size.
Preferably, the sixth aspect of the invention provides the control device of a vehicle drive device recited in the fifth aspect of the invention, wherein a control portion supplied with an oil temperature signal from the oil temperature sensor is separated from a control portion configured to control the oil temperature based on the solenoid current of the electromagnetic valve. As a result, even if a failure or communication abnormality occurs in the oil pressure sensor, the oil temperature can be calculated based on the solenoid current of the electromagnetic valve without being affected and the surge absorption circuit can certainly be prevented from increasing in size.
Preferably, the seventh aspect of the invention provides the control device of a vehicle drive device recited in the first aspect of the invention, wherein a mechanical oil pump driven by an engine is further included, and wherein the electromagnetic valve oil pump is driven during stop of the engine. As a result, although the mechanical oil pump is stopped during stop of the engine, the electromagnetic valve oil pump is driven instead and, therefore, insufficient supply of the hydraulic oil can be avoided.
Preferably, the eighth aspect of the invention provides the control device of a vehicle drive device recited in the seventh aspect of the invention, wherein the hydraulic oil discharged from the electromagnetic valve oil pump is supplied to a start clutch of a transmission. As a result, although the mechanical oil pump is stopped by stopping the engine during stop of the vehicle, since the hydraulic oil is supplied from the electromagnetic valve oil pump to the start clutch of the transmission during this period, the start clutch of the transmission can promptly be engaged to enable a smooth start when the vehicle is restarted.
Preferably, the ninth aspect of the invention provides the control device of a vehicle drive device recited in the first aspect of the invention, wherein the electromagnetic valve oil pump has an intake oil passage for sucking the hydraulic oil and a discharge oil passage for discharging the hydraulic oil, and wherein a cross-sectional area of the intake oil passage is larger than a cross-sectional area of the discharge oil passage. Since this reduces the resistance acting on the hydraulic oil that is being sucked from the intake oil passage, the controllability of the electromagnetic valve oil pump is improved.
An example of the present invention will now be described in detail with reference to the drawings. In the following example, the figures are simplified or deformed as needed and portions are not necessarily precisely depicted in terms of dimension ratio, shape, etc.
FIRST EXAMPLEThe engine 12 is, for example, an internal combustion engine such as a gasoline engine and a diesel engine, and includes an electronic throttle valve 54 disposed in an intake pipe 50 and driven to open/close by a throttle actuator 52, a fuel injection device 56 injecting fuel into a cylinder, and an ignition device 58 igniting the injected fuel.
A wheel brake device 64 is a well-known drum brake or disk brake and is disposed for each of wheels (wheels including the drive wheels 14 as well as driven wheels) to brake the wheels in accordance with a depression operation of a foot brake pedal 66. In other words, the wheel brake device 64 brakes the wheels in accordance with a brake oil pressure generated by the depression operation of the foot brake pedal 66.
The vehicle drive device 10 includes an electronic control device 80 having a function as a vehicle engine control device controlling the engine 12. The electronic control device 80 includes, for example, a so-called microcomputer including a CPU, a RAM, a ROM, an input/output interface, etc., and executes signal processes in accordance with a program stored in advance in the ROM, while utilizing a temporary storage function of the RAM, to provide the output control of the engine 12, the shift control of the transmission mechanism portion 16, and the drive control of an electromagnetic valve oil pump 86 described later. The electronic control device 80 is made up of a plurality of control devices such as an E/G-ECU exclusively executing the output control of the engine 12, an A/T-ECU exclusively executing the shift control of the transmission mechanism portion 16, and an O/P-ECU exclusively executing the drive control of the electromagnetic valve oil pump 86, and data are transferred among these control devices to each other through communication.
The electronic control device 80 is supplied with, for example, an engine rotation speed signal corresponding to a crank angle (position) Acr of a crankshaft and an engine rotation speed Ne of the engine 12 from an engine rotation speed sensor 28, an input rotation speed signal corresponding to a rotation speed Nin of an input shaft of the transmission mechanism portion 16 from an input rotation speed sensor 30, a vehicle speed signal indicative of a vehicle speed V corresponding to a rotation speed Nout of the output gear 18 from a vehicle speed sensor 32, wheel speed signals corresponding to rotation speeds Nw of the wheels from wheel speed sensors 34, a signal indicative of the presence of operation of an accelerator pedal 68 and an operation amount (accelerator opening degree Acc) of the accelerator pedal 68 from an accelerator opening degree sensor 36, a signal from a footbrake switch 38 indicative of the presence of a brake operation for causing the wheel brake device 64 to brake the wheels, i.e., the presence of the depression operation of the brake pedal 66, and a signal indicative of an oil temperature Toil of hydraulic oil from an oil temperature sensor 40.
The electronic control device 80 outputs, for example, engine output control command signals for the output control of the engine 12, for example, a drive signal to the throttle actuator 52 establishing an opening degree θth (throttle valve opening degree θth) of the electronic throttle valve 54, a fuel supply amount signal controlling an amount of fuel supply into each cylinder of the engine 12 by the fuel injection device 56, and an ignition signal commanding the timing of ignition of the engine 12 by the ignition device 58; a shift control command signal for the shift control of the transmission mechanism portion 16; and a drive signal driving the electromagnetic valve oil pump 86. For example, the electronic control device 80 outputs the shift control command signal to a hydraulic control circuit (not depicted) based on the input rotation speed signal, an output rotation speed signal, etc., so as to provide the switching control of the gear ratio of the transmission mechanism portion 16. Basically, the electronic control device 80 drives the throttle actuator 52 based on the accelerator opening degree Acc from a relationship (not depicted) stored in advance, as part of the output control of the engine 12, so as to provide throttle control such that the throttle valve opening degree θth is increased with an increase in the accelerator opening degree Acc. When the engine 12 is stopped, the electronic control device 80 provides control of driving the electromagnetic valve oil pump 86.
The electronic control device 80 of this example provides so-called idling reduction control of temporarily automatically stopping the engine 12 in association with a stop of running of the vehicle for fuel efficiency improvement. For example, in such a case that the vehicle waits for a traffic light, the vehicle is stopped while a shift range is a D-range with the brake pedal 66 depressed, and the engine 12 is temporarily automatically stopped in this case. Since the temporary stop of the engine 12 in the idling reduction control means that the fuel supply to the engine is stopped to put the engine 12 into a non-drive state and the engine rotation speed Ne is not limited to zero in the non-drive state, the temporary stop of the engine 12 includes the case that the engine rotation speed Ne is not zero. The fuel efficiency in this example refers to a running distance per unit fuel consumption etc., and an improvement in fuel efficiency refers to extension of the running distance per unit fuel consumption, or a reduction in fuel consumption rate (=fuel consumption/drive wheel output) of the vehicle as a whole. Contrarily, a reduction (deterioration) in fuel efficiency refers to shortening of the running distance per unit fuel consumption or an increase in fuel consumption rate of the vehicle as a whole.
When the accelerator pedal 68 is depressed in the state of the idle reduction control, a prompt start of the vehicle is desirable. However, since the engine 12 is stopped during the idle reduction control, a mechanical oil pump driven by the engine 12 is also stopped. Therefore, a delay may occur in engagement of a start clutch C1 of the transmission mechanism portion 16 engaged at the start of the vehicle, and the start responsiveness of the vehicle may deteriorate. In this regard, the vehicle of this example drives the electromagnetic valve oil pump 86 described later instead of the mechanical pump during the idle reduction control (during engine stop) to supply the hydraulic oil to the start clutch C1 in advance so that a state immediately before engagement is achieved, thereby enabling a prompt start.
The mechanical oil pump 84 is driven when the engine 12 is driven, and pumps up the hydraulic oil stored in an oil pan 88 to discharge the hydraulic oil toward a pressure adjusting circuit 90. The pressure adjusting circuit 90 includes, for example, a regulator valve (not depicted) and uses the hydraulic oil discharged from the mechanical oil pump 84 as an original pressure to adjust an optimum line pressure depending on a running state of the vehicle. A solenoid valve SL1 uses the line pressure as an original pressure to adjust the line pressure to an optimum clutch pressure Pc1 depending on the running state of the vehicle. This adjusted clutch pressure Pc1 is supplied via the switching valve 93 to the start clutch C1.
The electromagnetic valve oil pump 86 pumps up the hydraulic oil stored in the oil pan 88 to supply the hydraulic oil via the switching valve 93 to the start clutch C1. The switching valve 93 is a switching valve switching between the solenoid valve SL1 and the electromagnetic valve oil pump 86, through which the hydraulic oil is to be supplied to the start clutch C1. If the mechanical oil pump 84 is operated, the switching valve 93 allows the communication between the solenoid valve SL1 and the start clutch C1 and interrupts the communication between the electromagnetic valve oil pump 86 and the start clutch C1. If the mechanical oil pump 86 is not driven, the switching valve 93 allows the communication between the electromagnetic valve oil pump 86 and the start clutch C1 and interrupts the communication between the solenoid valve SL1 and the start clutch C1. Specific structure and operation of the switching valve 93 are known techniques and therefore will not be described. The hydraulic oil discharged from the electromagnetic valve oil pump 86 is directly supplied via the switching valve 93 to the start clutch C1, without the supplied hydraulic oil being adjusted. Therefore, the electromagnetic valve oil pump 86 is an oil pump supplying the hydraulic oil to the start clutch C1 exclusively during the idle reduction control.
As depicted in
The electromagnetic valve oil pump 86 of this example includes a drive frequency switching circuit 108 switching the drive frequency F, and the discharge amount of the electromagnetic valve oil pump 86 can be adjusted by switching the drive frequency F. When the plunger 94 is moved by the biasing force of the spring 98 in the solenoid coil 96 as depicted in
Therefore, a surge absorption circuit 110 for absorbing this surge power is interposed between the solenoid coil 96 of the electromagnetic valve oil pump 86 and the drive frequency switching circuit 108. The surge absorption circuit 110 includes a rectifier diode 112 and a Zener diode 114, for example. A surge absorption power W absorbed by the surge absorption circuit 110 is calculated by following Equation (1). In Equation (1), I denotes a solenoid current [A]; Vz denotes a Zener voltage [V]; t denotes a surge width [s] depicted in
W=I×Vz×t×F (1)
When the surge absorption power W becomes larger, a circuit scale of the surge absorption circuit 110 increases for ensuring heat resistance and costs become higher. Therefore, it is desirable to reduce the surge absorption power W.
A hydraulic circuit (corresponding to a hydraulic circuit of the present invention) including the discharge oil passage 100 and the switching valve 93 and connecting the electromagnetic valve oil pump 86 and the start clutch C1 is formed in a valve body (not depicted), and leakage of the hydraulic oil occurs when the hydraulic oil passes through the valve body.
When the electromagnetic valve oil pump 86 is driven in this example, the drive frequency F of the electromagnetic valve oil pump 86 is changed depending on the oil temperature Toil of the hydraulic oil to optimally control the discharge flow amount from the electromagnetic valve oil pump 86, thereby suppressing the surge absorption power W and preventing the surge absorption circuit 110 from increasing in size. Specifically, the drive frequency F is set lower in the case of low temperature as compared to the case of high temperature, thereby suppressing the surge absorption power W and preventing the surge absorption circuit 110 from increasing in size. A main portion of the present invention, i.e., the drive control of the electromagnetic valve oil pump 86 will hereinafter be described.
An oil temperature detecting portion 130 (an oil temperature detecting means) depicted in
A required flow rate calculating portion 132 (a required flow rate calculating means) calculates a required flow rate Q [cc/min] required for the electromagnetic valve oil pump 86 based on the oil temperature Toil obtained by the oil temperature detecting portion 130. The required flow rate Q is a flow rate of the hydraulic oil required for the start clutch C1.
A drive frequency calculating portion 134 (a drive frequency calculating means) determines the drive frequency F [Hz] of the electromagnetic valve oil pump 86 based on the required flow rate Q obtained by the required flow rate calculating portion 132.
A drive frequency changing portion 136 outputs, to the drive frequency switching circuit 108, a command for driving the electromagnetic valve oil pump 86 such that the electromagnetic valve 104 is turned on and off at the drive frequency F obtained by the drive frequency calculating portion 134. When this control is provided, the drive frequency F becomes lower in the case of low oil temperature as compared to the case of high oil temperature in accordance with the maps of
In
As described above, according to this example, the drive frequency F of operation of the electromagnetic valve oil pump 86 is set lower when the oil temperature Toil is low than when the oil temperature Toil is high. This setting makes the drive frequency F lower and therefore makes the discharge amount of the electromagnetic valve oil pump 86 smaller when the oil temperature Toil is low; however, since the leakage amount of the hydraulic oil becomes smaller, the required flow rate can be ensured. Since the surge absorption power W is proportional to the drive frequency F, the surge absorption power W becomes small even at the time of low oil temperature and, therefore, the surge absorption circuit 110 can be reduced in size. On the other hand, the leakage amount becomes larger at the time of high oil temperature and, therefore, the drive frequency F is made higher to increase the discharge amount of the electromagnetic valve oil pump 86; however, since the viscous resistance of the hydraulic oil is small at the time of high oil temperature and the solenoid current I becomes lower as compared to the time of low temperature, the surge absorption power W does not become large. Thus, the surge absorption circuit 110 can be reduced in size. Since the drive frequency F becomes lower at the time of low oil temperature, extra hydraulic oil is not discharged at the time of low oil temperature, and fuel efficiency deterioration and a transmission shock due to excessive toque of the start clutch C1 are prevented.
According to this example, the oil temperature Toil of the hydraulic oil is calculated based on the solenoid current I of the electromagnetic valve. As a result, the oil temperature can be detected without using a sensor etc.
According to this example, the drive frequency F of the electromagnetic valve oil pump 86 continuously varies depending on the oil temperature Toil. As a result, the drive frequency F is set such that the required flow rate can be ensured depending on the oil temperature Toil, and an extra flow rate and oil pressure can be suppressed to prevent the energy loss.
According to this example, the mechanical oil pump 84 driven by the engine 12 is further included and the electromagnetic valve oil pump 86 is driven during stop of the engine 12. As a result, although the mechanical oil pump 84 is stopped during stop of the engine, the electromagnetic valve oil pump 86 is driven instead and, therefore, insufficient supply of the hydraulic oil to the start clutch C1 can be avoided.
According to this example, the hydraulic oil discharged from the electromagnetic valve oil pump 86 is supplied to the start clutch C1 of the transmission mechanism portion 16. As a result, although the mechanical oil pump 84 is stopped by stopping the engine 12 during stop of the vehicle, since the hydraulic oil is supplied from the electromagnetic valve oil pump 86 to the start clutch C1 of the transmission mechanism portion 16 during this period, the start clutch C1 of the transmission mechanism portion 16 can promptly be engaged to enable a smooth start when the vehicle is restarted.
Another example of the present invention will be described. In the following description, the portions common to the examples are denoted by the same reference numerals and will not be described.
SECOND EXAMPLEAlthough the drive frequency F of the electromagnetic valve oil pump 86 is continuously changed in the example described above, the drive frequency F may be changed in stages (stepwise).
A thick solid line depicted in
In this example, a value (about 2.7 W) indicated by a dashed-dotted line depicted in
As described above, according to this example, substantially the same effect as the above-described example is acquired and, since the drive frequency F of the electromagnetic valve oil pump 86 varies in stages based on preset threshold values of the oil temperature Toil, the drive frequency F varies based on the threshold values of the oil temperature Toil and the required flow rate can be ensured while suppressing the surge absorption power W.
THIRD EXAMPLEAlthough the oil temperature detecting portion 130 detects the oil temperature Toil through direct detection by the oil temperature sensor 40 or indirect calculation from the solenoid current I relevant to the oil temperature Toil in the above-described examples, the both oil temperature detections are used and the oil temperature Toil is detected by a selected one of the detections in this example.
The oil temperature detecting portion 130 of this example includes both the oil temperature detection by the oil temperature sensor 40 and the oil temperature detection from calculation based on the solenoid current I, and the oil temperature Toil is normally directly detected by the oil temperature sensor 40. The oil temperature detection by the oil temperature sensor 40 is direct oil temperature detection and is therefore more accurate as compared to the case of indirect detection based on the solenoid current I. Therefore, the oil temperature Toil is normally detected by the oil temperature sensor 40.
If the oil temperature detection by the oil temperature sensor 40 becomes difficult because of a failure of the oil pressure sensor 40 etc., the oil temperature Toil is undetectable in a configuration unable to detect an oil temperature based on the solenoid current I and, therefore, the pump is driven at a high drive frequency F so as to avoid an insufficient required flow rate Q, resulting in a larger surge absorption power W and leading to an increase in size of the surge absorption circuit. Alternatively, the idle reduction control is terminated to constantly drive the engine 12, resulting in deterioration in fuel efficiency. In contrast, the oil temperature detecting portion 130 of this example determines whether the oil temperature detection by the oil temperature sensor 40 is available and, if the oil temperature detection by the oil temperature sensor 40 becomes unavailable, a switchover is performed to select the method of detecting the oil temperature Toil from the solenoid current I so as to enable the oil temperature detection even when the oil temperature detection by the oil temperature sensor 40 is impossible, thereby certainly preventing the increase in size of the surge absorption circuit 110 and the termination of the idle reduction control.
As depicted in the functional block diagram of
In this way, since the oil temperature detecting portion 130 of this example detects the oil temperature Toil by normally the oil temperature sensor 40, and calculates the oil temperature Toil based on the solenoid current I if the detection of the oil temperature Toil by the oil temperature sensor 40 is difficult, the oil temperature Toil can certainly be detected by calculating the oil temperature Toil based on the solenoid current I so as to avoid the increase in size of the surge absorption circuit 110 and the termination of the idle reduction control.
As described above, according to this example, the oil temperature Toil of the hydraulic oil is detected by the oil temperature sensor 40 and calculated based on the solenoid current I of the electromagnetic valve, and the oil temperature Toil is normally detected by the oil temperature sensor 40, while the oil temperature Toil is calculated based on the solenoid current I when the oil temperature Toil is not detected by the oil temperature sensor 40. As a result, a reliable value of the oil temperature Toil is normally detected by the oil temperature sensor 40 and, even if the oil temperature Toil cannot be detected by the oil temperature sensor 40, the oil temperature Toil can be calculated based on the solenoid current I of the electromagnetic valve, and the optimum drive frequency F can be set based on the oil temperature Toil. For example, if the oil temperature Toil is detected only by the oil temperature sensor 40 and the detection by the oil temperature sensor 40 becomes unavailable, the optimum discharge amount of the electromagnetic valve oil pump 86 based on the oil temperature Toil becomes unknown and, therefore, the drive frequency F must be made high so as to ensure the discharge amount. Thus, the surge absorption power W becomes large, which necessitates corresponding enlargement of the surge absorption circuit 110. In contrast, since the oil temperature Toil can be calculated based on the solenoid current I of the electromagnetic valve in this example, even if the oil temperature Toil cannot be detected by the oil pressure sensor 40, the oil temperature Toil is calculated based on the solenoid current I of the electromagnetic valve so as to set the drive frequency F to an optimum value and, therefore, the surge absorption power is suppressed so that the surge absorption circuit 110 is certainly prevented from increasing in size.
According to this example, the A/T-ECU supplied with the oil temperature signal from the oil temperature sensor 40 is separated from the O/P-ECU configured to control the oil temperature based on the solenoid current I of the electromagnetic valve. As a result, even if a failure or communication abnormality occurs in the oil pressure sensor 40, the oil temperature Toil can be calculated based on the solenoid current I of the electromagnetic valve without being affected and the surge absorption circuit 110 can certainly be prevented from increasing in size.
Although the examples of the present invention have been described in detail with reference to the drawings, the present invention is applied also in other forms.
For example, the examples described above may not necessarily independently be implemented and may be implemented in combination as needed without contradiction.
Although the hydraulic oil discharged from the electromagnetic valve oil pump 86 is supplied to the start clutch C1 of the transmission mechanism portion 16 in the examples, the start clutch C1 is not a limitation and the hydraulic oil may be supplied to any actuator driven by an oil pressure without particular limitation. Although the hydraulic oil discharged from the electromagnetic valve oil pump 86 is supplied only to the start clutch C1 in the examples, the hydraulic oil may selectively be supplied via a switching valve etc. to another actuator.
Although a method of directly detecting the oil temperature Toil from the oil temperature sensor 40 or a method of calculating the oil temperature Toil based on the solenoid current I is applied in the examples, the oil temperature Toil may be detected by either one of the methods. Although the solenoid current I is applied as a parameter related to the oil temperature Toil, any parameter such as an engine water temperature may be employed as needed as long as the oil temperature Toil can indirectly be estimated from the employed parameter.
Although the surge absorption circuit 110 is made up of one rectifier diode and two Zener diodes coupled in series in the examples, this configuration is an example and may be changed as needed without contradiction. Since the maximum value of the surge absorption power W is reduced in the present invention, the surge absorption circuit 110 is accordingly designed to be small.
In the examples, the specific configuration of the electromagnetic valve oil pump 86 is an example and any configuration is applicable as needed as long as the applied configuration enables the discharge amount to be variable by changing the drive frequency F of the electromagnetic valve.
Although the relation maps depicted in
The above description is merely an embodiment and the present invention can be implemented in variously modified and improved forms based on the knowledge of those skilled in the art.
NOMENCLATURE OF ELEMENTS10: vehicle drive device
12: engine
16: transmission mechanical portion (transmission)
40: oil temperature sensor
80: electronic control device (control device)
84: mechanical oil pump
86: electromagnetic valve oil pump
99: intake oil passage
100: discharge oil passage
104: electromagnetic valve
110: surge absorption circuit
130: oil temperature detecting portion (means of detecting an oil temperature)
136: drive frequency changing portion (means of controlling a drive frequency)
C1: start clutch
A/T-ECU: control portion supplied with an oil temperature signal from an oil temperature sensor
O/P-ECU: control portion configured to control an oil temperature based on a solenoid current of an electromagnetic valve
Claims
1. A control device of a vehicle drive device including an electromagnetic valve oil pump sucking and discharging hydraulic oil through ON/OFF operations of an electromagnetic valve, a drive frequency controller for controlling a drive frequency at which the electromagnetic valve is to be turned on/off, a temperature sensor for detecting an oil temperature of the hydraulic oil, and a hydraulic circuit supplied with the hydraulic oil discharged from the electromagnetic valve oil pump,
- the control device of a vehicle drive device further including a surge absorption circuit absorbing a counter electromotive force generated in the electromagnetic valve oil pump,
- the drive frequency of operation of the electromagnetic valve oil pump being set lower when the oil temperature is low than when the oil temperature is high.
2. The control device of a vehicle drive device of claim 1, wherein the oil temperature of the hydraulic oil is calculated based on a solenoid current of the electromagnetic valve.
3. The control device of a vehicle drive device of claim 1, wherein the drive frequency of the electromagnetic valve oil pump continuously varies depending on the oil temperature.
4. The control device of a vehicle drive device of claim 1, wherein the drive frequency of the electromagnetic valve oil pump varies in stages based on a preset threshold value of the oil temperature.
5. The control device of a vehicle drive device of claim 1, wherein the oil temperature of the hydraulic oil is detected by an oil temperature sensor and calculated based on the solenoid current of the electromagnetic valve, wherein
- the oil temperature is normally detected by the oil temperature sensor, and is calculated based on the solenoid current when the oil temperature is not detected by the oil temperature sensor.
6. The control device of a vehicle drive device of claim 5, wherein a control portion supplied with an oil temperature signal from the oil temperature sensor is separated from a control portion configured to control the oil temperature based on the solenoid current of the electromagnetic valve.
7. The control device of a vehicle drive device of claim 1, wherein a mechanical oil pump driven by an engine is further included, and wherein
- the electromagnetic valve oil pump is driven during stop of the engine.
8. The control device of a vehicle drive device of claim 7, wherein the hydraulic oil discharged from the electromagnetic valve oil pump is supplied to a start clutch of a transmission.
9. The control device of a vehicle drive device of claim 1, wherein the electromagnetic valve oil pump has an intake oil passage for sucking the hydraulic oil and a discharge oil passage for discharging the hydraulic oil, and wherein a cross-sectional area of the intake oil passage is larger than a cross-sectional area of the discharge oil passage.
Type: Application
Filed: Dec 27, 2012
Publication Date: Nov 19, 2015
Applicant: TOYOTA JIDOSHA KABUSHIKI KAISHA (Toyota-shi, Aichi)
Inventors: Yasuhide MIZUNO , Shinichi ITO (Toyota-shi), Hideki KUBONOYA (Toyota-shi)
Application Number: 14/654,946