JP2014169597A - Construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a construction machine in which deterioration of a power storage device is suppressed while the power storage device can be effectively warmed up.SOLUTION: A construction machine comprises a controller 14 that controls an inverter 10 so that a warming-up control is performed to repeat charging/discharging of a power storage device 9 when the temperature of the power storage device 9 is lower than a pre-set reference temperature. While the controller 14 switches, in warming-up control, from a charging state to a discharging state when a voltage detected by a voltage detector 12 exceeds a pre-set first threshold during the charging of the power storage device 9, it switches from the discharging state to the charging state when a voltage detected by the voltage detector 12 is lower than a pre-set second threshold during the discharging of the power storage device 9.

Description

  The present invention relates to a hybrid construction machine capable of performing predetermined work using engine power and assisting the engine using electric power generated by the engine power and charged in a power storage device.

  A hybrid construction machine includes an engine, a power storage device, a generator motor that operates as a power generator by power from the engine and also operates as a motor by power from the power storage device, and an inverter that controls charging and discharging of the power storage device. I have.

  Here, it is desirable to warm up the power storage device because the internal resistance increases and the charge / discharge performance decreases in a low temperature environment.

  Conventionally, as a technology for warming up the power storage device, a technology is known in which charging and discharging of the power storage device is repeated when the temperature of the power storage device is lower than a predetermined temperature, and the power storage device is warmed up by internal heat generation (for example, Patent Document 1).

  In the construction machine described in Patent Literature 1, a method of raising and lowering a target SOC (State of Charge: hereinafter referred to as a charging rate) for the power storage device is employed.

JP 2010-127271 A

  When the method of raising or lowering the target charging rate is adopted, it is assumed that the current charging rate is estimated or grasped. As the means, for example, a method of estimating the current charging rate based on an integrated value of charged and discharged current values is known.

  However, in a low temperature environment, since the internal resistance of the power storage device is large, the fluctuation of the voltage between terminals due to charging / discharging is large, and the charging / discharging current is limited to a small value, so that the above method is also effective in the low temperature environment. The charging rate cannot be estimated accurately.

  For this reason, in the warm-up method by raising and lowering the target charging rate, proper charge / discharge control becomes difficult.

  In addition, in order to improve the warm-up efficiency of the power storage device, it is desirable to flow a large current, but in the situation where it is difficult to accurately estimate the current charging rate as described above, the estimation error is taken into consideration. Thus, the current value has to be limited to a small value, and it is not possible to sufficiently warm up. That is, the warm-up efficiency is poor.

  On the other hand, if a large current continues to flow in one direction (charging direction or discharging direction) without limiting the current, the warm-up efficiency increases, but the voltage between terminals exceeds the allowable range under low temperature conditions with high internal resistance. This may accelerate the deterioration of the power storage device.

  An object of the present invention is to provide a construction machine that can efficiently warm up a power storage device while suppressing deterioration of the power storage device.

  In order to solve the above-described problems, the present invention provides an engine, a power storage device, a generator motor that operates as a power generator by power from the engine, and that operates as a motor by power from the power storage device, and the power generator motor And a charge / discharge controller that controls charging and discharging of the power storage device, temperature detection means for detecting the temperature of the power storage device, voltage detection means for detecting the voltage of the power storage device, and detection by the temperature detection means The charge / discharge control is performed so that the warm-up control for repeating charge / discharge of the power storage device is executed when it is determined that the temperature of the power storage device is under a low temperature condition lower than a preset reference temperature. A warm-up controller for controlling the warming-up controller, wherein the warm-up controller is configured to preliminarily set a voltage detected by the voltage detecting means during charging of the power storage device in the warm-up control. Switching from the charged state to the discharged state when exceeding the set first threshold value, while charging from the discharged state when the voltage detected by the voltage detecting means during the discharging of the power storage device falls below a preset second threshold value Provide a construction machine that switches to a state.

  Here, the first threshold value is set as an allowable voltage on the high voltage side so as not to cause deterioration of the power storage device, and the second threshold value is set as an allowable voltage on the low voltage side so as not to cause deterioration of the power storage device. Value. That is, in the present invention, the current value during charging / discharging can be set large within a range not exceeding both threshold values.

  As described above, according to the present invention, since the power storage device is warmed up by voltage monitoring that switches between charge and discharge based on the voltage of the power storage device as the first threshold value and the second threshold value, the target charge rate is increased and decreased as in the past. Compared with the case where it carries out, the electric current value at the time of charging / discharging can be set largely within the range of the allowable voltage of an electrical storage apparatus.

  Therefore, according to the present invention, the power storage device can be efficiently warmed up while suppressing the deterioration of the power storage device.

  The construction machine further includes work detection means for detecting the presence or absence of a work operation, and the warm-up controller is configured to detect the warm-up when the work operation is detected by the work detection means during the execution period of the warm-up control. While the machine control is interrupted, it is preferable to resume the warm-up control when it is detected by the work detection means that there is no work operation during the warm-up control interruption period.

  Here, the “work operation” includes an operation for performing an operation performed using at least one of the power of the engine and the electric power of the power storage device, and an operation for entering a work state before the operation.

  According to the said aspect, when work operation is performed, warming-up of an electrical storage apparatus can be interrupted and priority can be given to the work of a construction machine. Therefore, by continuing warming-up of the power storage device during work of the construction machine, it is possible to suppress problems such as engine power required for work or power storage device power shortage.

  In the construction machine, the warm-up controller executes the warm-up control by setting an upper limit of a current value charged to the power storage device and a current value discharged from the power storage device during the interruption period of the warm-up control. It is preferable to limit the upper limit during the period.

  Even during the warm-up control interruption period, the current value at the time of charging and discharging of the power storage device under the low temperature condition needs to be limited more than the current value of the power storage device under the low temperature condition. Furthermore, unlike the execution period of the warm-up control, when the construction machine is performing a work operation, the current flow in the power storage device is unidirectional (discharge side or charge side, depending on the operation of the engine or generator motor). In particular, it often occurs continuously on the discharge side), and the voltage of the power storage device may exceed the allowable voltage.

  Therefore, as in the above-described aspect, by limiting the upper limit of the current value related to charging / discharging during the warm-up control interruption period more than the upper limit during the warm-up control period, the voltage of the power storage device is prevented from exceeding the allowable range. can do.

  Therefore, according to the aspect, it is possible to more reliably prevent deterioration of the power storage device while giving priority to the work of the construction machine over the warm-up of the power storage device as described above.

  In the construction machine, the warm-up controller sets an upper limit of a current value charged in the power storage device and a current value discharged from the power storage device during the interruption period of the warm-up control. It is preferable that the lower the limit, the smaller.

  According to the above aspect, since the current value can be limited according to the temperature (internal resistance) of the power storage device during the warm-up control interruption period, the deterioration of the power storage apparatus can be prevented even during the warm-up control interruption period. Can be prevented.

  The construction machine may further include an actuator for performing the predetermined work and an operation unit that outputs an operation command for the actuator, and the work detection unit is capable of detecting an operation command by the operation unit. preferable.

  Further, the construction machine includes a boarding / blocking lever that is operated to close the entrance / exit of the construction machine when working and open when the work is stopped, and the work detection means detects the closing operation of the boarding / closing boarding lever Is preferred.

  According to these aspects, it is possible to reliably detect whether or not a work operation has been performed by the work detection means.

  ADVANTAGE OF THE INVENTION According to this invention, an electrical storage apparatus can be warmed up efficiently, suppressing deterioration of an electrical storage apparatus.

1 is a left side view illustrating an overall configuration of a hydraulic excavator according to a first embodiment of the present invention. It is the schematic which shows the drive system of the hybrid shovel shown in FIG. It is a flowchart which shows the process performed by the controller shown in FIG. FIG. 3 is a view corresponding to FIG. 2 of a hybrid excavator according to a second embodiment of the present invention. FIG. 5 is a low temperature output map stored in the controller shown in FIG. 4. FIG. It is a flowchart which shows the process performed by the controller shown in FIG.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. The following embodiments are examples embodying the present invention, and are not of a nature that limits the technical scope of the present invention.

(First embodiment)
Referring to FIG. 1, a hybrid excavator 1 as an example of a construction machine includes a crawler-type lower traveling body 2, an upper revolving body 3 that is turnably provided on the lower traveling body 2, and an upper revolving body 3. The attached work attachment 4 is provided.

  The work attachment 4 includes a boom 15 that can be raised and lowered with respect to the upper swing body 3, an arm 16 that is swingably attached to the tip of the boom 15, and a swing with respect to the tip of the arm 16. And a bucket 17 movably attached thereto.

  Further, the work attachment 4 swings the boom cylinder 18 that raises and lowers the boom 15 with respect to the upper swing body 3, the arm cylinder 19 that swings the arm 16 with respect to the boom 15, and the bucket 17 with respect to the arm 16. The bucket cylinder 20 is provided.

  Hereinafter, the drive system of the hybrid excavator 1 will be described with reference to FIG.

  The hybrid excavator 1 includes an engine 5, a hydraulic pump 6 and a generator motor 8 connected to an output shaft of the engine 5, and a control valve 7 that controls supply and discharge of hydraulic oil from the hydraulic pump 6 to the cylinders 18 to 20. , A power storage device 9 capable of charging the power generated by the generator motor 8, an inverter (charge / discharge controller) 10 that controls charging / discharging of the power storage device 9 and the operation of the generator motor 8, and a temperature of the power storage device are detected. A temperature detector (temperature detection means) 11, a voltage detector (voltage detection means) 12 that detects a voltage between terminals of the power storage device 9, and a controller (warm-up controller) 14 that controls the inverter 10 are provided. Yes.

  The hydraulic pump 6 is operated by the power of the engine 5 and discharges hydraulic oil. The hydraulic oil discharged from the hydraulic pump 6 is guided to the cylinders 18 to 20 in a state where the flow rate is controlled by the control valve 7.

  The generator motor 8 operates as a generator by power from the engine 5 and operates as a motor by power from the power storage device 9.

  The inverter 10 controls switching between the operation of the generator motor 8 as a generator and the operation of the generator motor 8 as an electric motor. The inverter 10 controls the current to the generator motor 8 and the torque of the generator motor 8.

  When controller 14 determines that the temperature of power storage device 9 detected by temperature detector 11 is under a low temperature condition lower than a preset reference temperature, warm-up is repeated to charge and discharge power storage device 9. A charge / discharge switching unit 21 is provided for controlling the inverter 10 so that the control is executed.

  Specifically, in the warm-up control, the charge / discharge switching unit 21 switches from the charge state to the discharge state when the voltage detected by the voltage detector 12 during charging of the power storage device 9 exceeds the first threshold value. Here, the first threshold value is a value that is preset as an allowable voltage on the high voltage side so as not to cause deterioration of the power storage device 9 and stored in the controller 14.

  On the other hand, in the warm-up control, the charge / discharge switching unit 21 switches from the discharge state to the charge state when the voltage detected by the voltage detector 12 during the discharge of the power storage device 9 is lower than the second threshold value. Here, the second threshold value is a value that is set in advance as an allowable pressure on the low voltage side so as not to cause deterioration of the power storage device 9 and stored in the controller 14.

  Hereinafter, warm-up control executed by the controller 14 will be described with reference to FIG.

  When the warm-up control is executed, first, the temperature of the power storage device 9 is detected (step S1), and it is determined whether or not the detected temperature is lower than the reference temperature (step S2).

  If it is determined in step S2 that the detected temperature is lower than the reference temperature (YES in step S2), charging of power storage device 9 is started (step S3), and the voltage of power storage device 9 is detected (step S4). .

  Next, it is determined whether or not the detected voltage exceeds the first threshold value (step S5). Here, if it is determined that the detected voltage is equal to or lower than the first threshold value (NO in step S5), the power storage device 9 is charged. Is continued (step S3).

  On the other hand, if it is determined in step S5 that the detected voltage exceeds the first threshold value (YES in step S5), discharging of power storage device 9 is started, that is, the charging state is switched to the discharging state (step S6).

  Next, the voltage of the power storage device 9 is detected (step S7), and it is determined whether or not the detected voltage is lower than the second threshold value (step S8).

  If it is determined in step S8 that the detected voltage is equal to or higher than the second threshold value (NO in step S8), discharging of the power storage device 9 is continued (step S6).

  On the other hand, when it is determined in step S8 that the detected voltage is lower than the second threshold (YES in step S8), the process returns, and in step S2, it is determined that the detected temperature of the power storage device 9 is lower than the reference temperature. Then, charging of the power storage device 9 is started. That is, when the detected voltage falls below the second threshold, the discharge state is switched to the charge state.

  If it is determined in step S2 that the detected temperature is equal to or higher than the reference temperature (NO in step S2), that is, it is determined that the power storage device 9 is in a temperature condition that can be used normally, the process proceeds to normal control. Warm-up control ends.

  As described above, since the power storage device 9 is warmed up by voltage monitoring that switches between charge and discharge based on the voltage of the power storage device 9 as the first threshold value and the second threshold value, the target charging rate is increased and decreased as in the past. Compared to the case, the current value at the time of charging / discharging can be set large within the allowable voltage range of the power storage device 9.

  Therefore, the power storage device 9 can be efficiently warmed up in the shortest time while suppressing the deterioration of the power storage device 9.

(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described with reference to FIGS. In addition, about the structure similar to 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  The hybrid excavator 1 according to the second embodiment includes a remote control valve 23 as an operation means for outputting a pilot pressure (operation command) to the control valve 7 in order to operate the cylinders (actuators) 18 to 20, A pressure sensor 24 (work detection means) that detects the presence or absence of pilot pressure and an ECU 25 that controls driving of the engine 5 are provided.

  Further, the controller 14 outputs a command for interrupting the warm-up control to the charge / discharge switching unit 21 when the pilot pressure is detected by the pressure sensor 24 during the execution period of the warm-up control (FIG. 3). The charging / discharging limiting unit 22 for executing the charging / discharging limiting control for outputting a command to resume the warming-up control to the charging / discharging switching unit 21 when the pilot pressure is not detected during the interruption of the warming-up control.

  Here, the charging / discharging limiting unit 22 sets the upper limit of the current value charged in the power storage device 9 and the current value discharged from the power storage device 9 during the warm-up control interruption period as the upper limit during the warm-up control execution period. More restrictive.

  Specifically, charging / discharging limiting unit 22 relates to charging / discharging of power storage device 9 during the warm-up control interruption period (during work) based on the low temperature output map (FIG. 5) stored in advance in controller 14. Control power.

  The low temperature output map is set for each temperature of the power storage device 9 so that the voltage at the time of charge and discharge of the power storage device 9 falls within the allowable voltage range of the power storage device 9. Indicates the upper limit value.

  In addition, the low temperature output map includes an upper limit value L1 of discharge power during warm-up indicated by a solid line, an upper limit value L2 of discharge power during work indicated by a broken line, and an upper limit of charge power during work indicated by a two-dot chain line. A value L3 and an upper limit L4 of charging power during warm-up indicated by a one-dot chain line are set.

  The upper limit value L2 of the discharge power during work is set smaller than the upper limit value L1 of the discharge power during warm-up. Similarly, the upper limit L3 of charging power during work is set smaller than the upper limit L4 of charging power during warm-up (set smaller as a negative value).

  Here, since the internal resistance of the power storage device 9 is determined according to the temperature of the power storage device 9, the magnitude relationship between the upper limit values L <b> 1 to L <b> 4 specified at an arbitrary temperature in the low temperature output map is the voltage of the power storage device 9. Can be considered to be the magnitude relationship of the upper limit of the current value for falling within the allowable voltage.

  To be precise, the internal resistance of the power storage device 9 varies depending on the temperature and the charging rate of the power storage device 9. Therefore, originally, the charging / discharging map shown in FIG. 4 is also defined by the temperature and the charging rate of the power storage device 9, but the map shown in FIG. For the sake of convenience, FIG. 4 shows a map in the case where the charging rate is constant as an example.

  Therefore, by controlling the power of the power storage device 9 based on the low temperature output map and the temperature detected by the temperature detector 11, the upper limit of the current value related to charging / discharging of the power storage device 9 during operation is increased. The upper limit during the machine control execution period can be limited.

  Further, the charge / discharge limiting unit 22 determines the current value charged in the power storage device 9 and the current value discharged from the power storage device 9 during the warm-up control interruption period based on the low temperature output map and the detected temperature. The upper limit can be limited such that the lower the temperature of the power storage device 9 is, the smaller the upper limit is.

  Specifically, the charge / discharge limiting unit 22 controls the output of the generator motor 8 via the charge / discharge switching unit 21 and the inverter 10, and controls the output of the engine 5 via the ECU 25, thereby relating to the power storage device 9. Control power relatively.

  Hereinafter, with reference to FIG. 6, the charge / discharge restriction control executed by the controller 14 will be described.

  The charge / discharge restriction control is started together with the start of the warm-up control shown in FIG. 3. First, the pilot pressure (hereinafter referred to as operation pressure) of the remote control valve 23 operated by the lever is detected (step T1), and the detected operation is detected. It is determined whether or not the pressure is greater than the reference pressure (step T2).

  The reason for determining whether or not the operation pressure has exceeded the reference pressure in step T2 is to reliably detect that the lever operation has been performed beyond the dead zone.

  If it is determined in step T2 that the operating pressure does not exceed the reference pressure, step T1 is repeatedly executed. If it is determined in step T2 that the operating pressure exceeds the reference pressure, the warm-up control is interrupted. (Step T3).

  Next, the upper limit value of power is specified with reference to the low temperature output map shown in FIG. 5 (step T4). Specifically, in step T5, the temperature of the power storage device 9 is detected by the temperature detector 11, and the upper limit value of power is specified based on the detected temperature and the low temperature output map.

  When the upper limit value of the power is specified in this way, the power (current value) of the power storage device 9 is relatively controlled by controlling the output of the engine 5 and the output of the generator motor 8 (step T5).

  Next, it is determined whether or not the operating pressure is equal to or lower than the reference pressure (step T6). If it is determined that the operating pressure is higher than the reference pressure (NO in step T6), step T4 is repeatedly executed.

  On the other hand, if it is determined that the operating pressure is equal to or lower than the reference pressure (YES in step T6), the warm-up control shown in FIG. 3 is resumed and the process returns.

  In addition, when the power storage device 9 is warmed up to the reference temperature as a result of the charge / discharge accompanying the operation according to the lever operation, when the warm-up control is resumed in step T6, the reference is made in step S2 shown in FIG. It is determined that the temperature is higher than the temperature (YES in step S2), and the routine proceeds to normal control (step S9).

  Further, the charge / discharge restriction control ends with the end of the warm-up control.

  As described above, according to the second embodiment, when a work using the work attachment 4 is performed, the warm-up of the power storage device 9 can be interrupted and the work can be performed with priority. Therefore, by continuing warming-up of the power storage device 9 during the work of the work attachment 4, it is possible to suppress problems such as insufficient power of the engine 5 or power of the power storage device 9 required for the work.

  Even during the warm-up control interruption period (steps T3 to T6), the current value during charging / discharging of the power storage device 9 under the low temperature condition needs to be limited more than the current value of the power storage device not under the low temperature condition. Furthermore, unlike the execution period of the warm-up control, in the state where the work attachment 4 is working, the current flow in the power storage device 9 is unidirectional (on the discharge side or in accordance with the operation of the engine 5 or the generator motor 8). It often occurs continuously on the charging side, particularly on the discharging side, and the voltage of the power storage device 9 may exceed the allowable range.

  Thus, as in the second embodiment, during the warm-up control interruption period (steps T3 to T6), by limiting the upper limit of the current value related to charging and discharging to the upper limit during the warm-up control period, It is possible to prevent the voltage from exceeding an allowable range.

  Therefore, according to the second embodiment, deterioration of the power storage device 9 can be prevented more reliably while giving priority to the work of the construction machine over the warming up of the power storage device 9 as described above.

  Further, according to the second embodiment, the current value can be limited according to the temperature (internal resistance) of the power storage device 9 during the interruption period of the warm-up control according to the low temperature output map shown in FIG. Therefore, deterioration of power storage device 9 can be prevented even during the warm-up control interruption period.

  In the second embodiment, the warm-up control is interrupted when the operation of each of the cylinders 18 to 20 is detected. However, the operation of the swing motor electrically connected to another actuator, for example, the power storage device 9 is not performed. The warm-up control can be interrupted at the time of detection.

  Further, in the second embodiment, it is detected that the remote control valve 23 has been operated, that is, that the work has actually started, but it has been detected that the operation state before the operation of the remote control valve 23 has been entered. The warm-up control can be interrupted.

  Specifically, the hybrid excavator 1 includes an entrance / exit cutoff lever 26 that opens and closes the entrance / exit like a circuit breaker, and a limit switch 27 that detects opening / closing of the entrance / exit cutoff lever 26, as indicated by a two-dot chain line in FIG. A system having an electromagnetic valve 28 that opens and closes in response to the operation of the limit switch 27 is provided. In this system, when the entry / exit cutoff lever 26 is opened when the operator gets off (when the operation is stopped), the solenoid valve 28 shuts off the pilot primary pressure circuit of the remote control valve 23 and the operation of the remote control valve 23 is invalidated. .

  Using this system, the limit switch 27 detects that the entry / exit blocking lever 26 has been closed, that is, the operator has been seated and has entered a work posture, and it is determined that the work operation has been performed in response to this detection. A configuration can be employed.

  Then, the charge / discharge limiting unit 22 omits step T1 shown in FIG. 6 and performs a step of determining whether or not there is a detection signal from the limit switch 27 instead of step T2, and instead of step T6. A step of determining whether there is no detection signal can be performed.

  Thereby, the effect similar to 2nd Embodiment can be acquired.

  In each of the above embodiments, when the detected temperature is determined to be lower than the reference temperature (YES in step S2), the power storage device 9 is charged. However, the discharge may be performed first.

1 Hybrid excavator (an example of construction machinery)
5 Engine 8 Generator motor 9 Power storage device 10 Inverter (an example of charge / discharge controller)
11 Temperature detector (example of temperature detection means)
12 Voltage detector (an example of voltage detection means)
14 Controller (example of warm-up controller)
18 Boom cylinder (an example of an actuator)
19 Arm cylinder (an example of an actuator)
20 Bucket cylinder (an example of an actuator)
23 Remote control valve (example of operating means)
24 Pressure sensor (an example of work detection means)
26 Entry / exit blocking lever (an example of locking means)
27 Limit switch (an example of locking means and work detection means)
28 Solenoid valve (an example of locking means)

Claims (6)

An engine,
A power storage device;
A generator motor that operates as a generator by power from the engine, and that operates as a motor by electric power from the power storage device;
A charge / discharge controller for controlling the operation of the generator motor and the charge / discharge of the power storage device;
Temperature detecting means for detecting the temperature of the power storage device;
Voltage detection means for detecting the voltage of the power storage device;
When it is determined that the temperature of the power storage device detected by the temperature detection unit is in a low temperature condition lower than a preset reference temperature, warm-up control that repeats charging and discharging of the power storage device is executed. A warm-up controller for controlling the charge / discharge controller as described above,
In the warm-up control, the warm-up controller switches from a charged state to a discharged state when a voltage detected by the voltage detecting unit during charging of the power storage device exceeds a preset first threshold value, A construction machine that switches from a discharged state to a charged state when a voltage detected by the voltage detection means is lower than a preset second threshold value during discharging of the power storage device. It further comprises work detection means for detecting the presence or absence of a work operation,
The warm-up controller interrupts the warm-up control when a work operation is detected by the work detection means during the warm-up control execution period, while the work detection during the warm-up control interruption period. The construction machine according to claim 1, wherein the warm-up control is resumed when it is detected by means that there is no work operation.   The warm-up controller determines an upper limit of a current value charged in the power storage device and a current value discharged from the power storage device during an interruption period of the warm-up control from an upper limit during the execution period of the warm-up control. The construction machine according to claim 2, which also restricts.   The warm-up controller reduces the upper limit of the current value charged in the power storage device and the current value discharged from the power storage device during the interruption period of the warm-up control as the temperature of the power storage device decreases. The construction machine according to claim 2 or 3, wherein An actuator for performing the predetermined operation;
Operation means for outputting an operation command for the actuator,
The construction machine according to any one of claims 2 to 4, wherein the work detection means is capable of detecting an operation command by the operation means. The entrance / exit of the construction machine is closed at the time of work, and is provided with a boarding / blocking lever operated to open at the time of work stoppage,
The construction machine according to any one of claims 2 to 4, wherein the work detection means detects a closing operation of the boarding / alighting interruption lever.

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