JP2015140755A - hydraulic unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic unit that prevents excess load from being applied to an engine to improve fuel consumption without adversely affecting working, even when automatic reproduction of the DPF is started during working.SOLUTION: A hydraulic pump 17 for DPF reproduction is provided separately with hydraulic pumps 12-16 for working, the discharge side of the hydraulic pump for DPF reproduction is connected to an oil tank 20 through an electromagnetic proportional relief valve 22 and an oil cooler 19, and provided is relief valve control means which adjusts the setting pressure of the electromagnetic proportional relief valve on the basis of signals from an engine controller.

Description

  The present invention relates to a hydraulic unit, and more particularly to a hydraulic unit that supplies a hydraulic oil to an actuator by driving a hydraulic pump in a diesel engine.

  Hydraulic units that use a diesel engine as the drive source of the hydraulic pump are mounted on various equipment such as cranes, pile driving machines, and hydraulic excavators, but depending on the work, they operate for a long time with a light load (low load). May continue. On the other hand, if the diesel engine as a driving source continues to operate at a light load, the particulate matter (PM) treatment in the diesel particulate filter (DPF) cannot be performed due to a decrease in the exhaust gas temperature, and PM is not contained in the DPF. May accumulate and cause clogging.

  For this reason, when the engine controller (ECU) determines that it is necessary, a regeneration operation is performed in which the engine load is automatically increased to increase the temperature of the exhaust gas and PM is processed to eliminate clogging of the DPF. It has been broken. As one of the means to increase engine load, exhaust gas by increasing the hydraulic pressure by increasing the circuit pressure by using unused control valves of multiple control valves and the unused positions of the control valves A DPF forced regeneration circuit that raises the temperature is known (see, for example, Patent Document 1).

Japanese Patent Application Laid-Open No. 2011-112004

  However, since the circuit described in Patent Document 1 incorporates a circuit for increasing the circuit pressure in the working hydraulic pump and the hydraulic circuit, if the regeneration of the DPF automatically starts during the work, the circuit pressure increasing As a result, the load for increasing the circuit pressure is added to the working hydraulic pump, and if the horsepower control is applied to the hydraulic pump due to the pressure increase, the flow rate decreases, so the working speed decreases. There was a risk of it. That is, the automatic regeneration of the DPF may adversely affect the work.

  Therefore, the present invention provides a hydraulic unit that can improve fuel efficiency without adversely affecting the work even when the automatic regeneration of the DPF starts during the work and preventing an excessive load on the engine. The purpose is to do.

  To achieve the above object, according to a first aspect of the hydraulic unit of the present invention, in the hydraulic unit that supplies a hydraulic oil to an actuator by driving a hydraulic pump with a diesel engine controlled by an engine controller, the diesel engine And a discharge side of the DPF regeneration hydraulic pump connected to the oil tank via an electromagnetic proportional relief valve and an oil cooler, and based on a signal from the engine controller A relief valve control means for adjusting a set pressure of the electromagnetic proportional relief valve is provided.

  Furthermore, in the first configuration, the relief valve control means receives an engine information receiving unit that receives information on the engine speed and torque from the engine controller, and outputs a current engine output from the received speed and torque. The calculated current engine output is compared with a preset engine output required for DPF regeneration, and when the current output is lower than the set output, the set pressure of the electromagnetic proportional relief valve And a valve controller that maintains or lowers the set pressure of the electromagnetic proportional relief valve when the current output is higher than the set output.

  Further, the second configuration of the hydraulic unit of the present invention is a DPF regeneration driven by the diesel engine in a hydraulic unit that supplies a hydraulic oil to an actuator by driving a hydraulic pump by a diesel engine controlled by an engine controller. Variable displacement hydraulic pump, and the discharge side of the DPF regeneration variable displacement hydraulic pump is connected to an oil tank via a relief valve with an unload function and an oil cooler, and the signal from the engine controller And a pump displacement control means for controlling the displacement of the DPF regeneration variable displacement hydraulic pump, and a relief valve control means for switching the relief valve with an unload function between an unloaded state and an operating state. It is said.

  Further, in the second configuration, the pump displacement control means includes an engine information receiving unit that receives information on the engine speed and torque from the engine controller, and a current engine output from the received speed and torque. The calculated current engine output is compared with a preset engine output required for DPF regeneration. When the current output is lower than the set output, the DPF regeneration variable displacement hydraulic pressure is calculated. A pump capacity control unit that increases the capacity of the pump and maintains or decreases the capacity of the variable displacement hydraulic pump for DPF regeneration when the current output is higher than the set output, and the relief valve control means includes: When the current output is higher than the set output, the relief valve with unload function is set to the unload state, and the set output When the output current is lower for is characterized in that the operating state of the relief valve with unloading function.

  According to the hydraulic unit of the present invention, a hydraulic pump dedicated to DPF regeneration that is activated during DPF regeneration is provided separately from the working hydraulic pump, and when the DPF is regenerated, the set pressure of the electromagnetic proportional relief valve is controlled. Since the load of the variable displacement hydraulic pump is controlled and the engine is loaded, even if the automatic regeneration of the DPF starts during the work, the work hydraulic pump is not adversely affected. Normal work can be continued.

It is a hydraulic circuit diagram of the principal part which shows the 1st example of a hydraulic unit of the present invention. It is a block diagram of a relief valve control means similarly. It is a hydraulic circuit diagram of the principal part which shows the 2nd example of a hydraulic unit of the present invention. It is a block diagram of a pump capacity | capacitance control means similarly.

  1 and 2 show a first embodiment of a hydraulic unit according to the present invention. FIG. 1 is a hydraulic circuit diagram of a main part, and FIG. 2 is a block diagram of a relief valve control means.

  The hydraulic unit shown in the present embodiment includes a plurality of hydraulic pumps driven by a diesel engine (hereinafter referred to as an engine) 11. For example, in the case of a hydraulic unit mounted on a crawler crane, the plurality of hydraulic pumps are five hydraulic pumps installed for normal work, that is, main pumps used for winches, traveling (left and right), etc. PV1, PV2) 12, 13 and sub-pumps (PF4, PF5, PF6) 14, 15, 16 used for turning, cylinders, pilots, etc., for DPF regeneration added for regeneration of DPF A hydraulic pump (P3) 17 is provided. Each of the main pumps 12 and 13 is a variable displacement type capable of horsepower control, and each of the sub-pumps 14, 15 and 16 is a fixed displacement type. The DPF regeneration hydraulic pump 17 is provided together with the main pumps 12 and 13 in a state of being directly connected to the drive shaft of the engine 11.

  The main pumps 12, 13 and the sub pumps 14, 15, 16 are incorporated in a well-known hydraulic circuit for supplying hydraulic fluid to a predetermined actuator or the like via a predetermined control circuit such as a control valve (not shown). It is. Furthermore, an oil cooling circuit 21 connected from the control valve 18 to the oil tank 20 via the oil cooler 19 is provided on the discharge side of the sub pump 14 in this embodiment.

  On the discharge side of the DPF regeneration hydraulic pump 17, a DPF regeneration circuit 23 connected to the oil tank 20 via the electromagnetic proportional relief valve 22 and the oil cooler 19 is provided. The set pressure of the electromagnetic proportional relief valve 22 is controlled by a controller 24 which is a relief valve control means shown in FIG. The controller 24 receives an engine information receiving unit that receives the rotational speed information 25a and torque information 25b of the engine 11 from an engine controller (ECU) 25 that controls the engine 11, and the current engine 11 based on the received rotational speed information and torque information. And the calculated current output of the engine 11 is compared with a preset output of the engine 11 required for DPF regeneration. When the current output is lower than the set output, the electromagnetic proportional When the set pressure of the relief valve 22 is increased and the current output is higher than the set output, a signal for maintaining or decreasing the set pressure of the electromagnetic proportional relief valve 22 is sent to the solenoid (SOL) of the electromagnetic proportional relief valve 22. -1) It has a valve control unit that transmits to 22a.

  When regeneration of the DPF is not necessary, the controller 24 sets the set pressure of the electromagnetic proportional relief valve 22 to the minimum pressure regardless of the operating state of the engine 11. Therefore, the hydraulic oil sucked from the oil tank 20 and discharged from the DPF regeneration hydraulic pump 17 passes through the fully open electromagnetic proportional relief valve 22 with almost no resistance, and is cooled and passed through the oil cooler 19 Returned to the tank 20. In other words, the circuit of the DPF regeneration hydraulic pump 17 functions as an oil cooling circuit for cooling the hydraulic oil at normal times when regeneration of the DPF is unnecessary.

  On the other hand, when the pressure increase in the exhaust gas system on the upstream side of the DPF is detected, or when the light load operation is continued beyond a preset time, automatic regeneration of the DPF starts. When regenerating the DPF, the controller 24 adjusts the set pressure of the electromagnetic proportional relief valve 22 in accordance with the operating state of the engine 11. For example, in order to increase the engine 11 torque received by the engine information receiving unit to T [kN-m], the rotational speed of the engine 11 to N [rpm], and the exhaust temperature of the engine 11 to a temperature necessary for regeneration of the DPF. When the required output (set output) of the engine 11 is set to L0 [kW], the valve control unit first calculates the current output L [kW] of the engine 11 from the received information as L = 2π / 60 × T ×. Calculated by N.

  Then, the current output L of the engine 11 is compared with the set output L0. If L> L0, that is, if the current output L of the engine 11 exceeds the set output L0, the current operation of the engine 11 is performed. Since the DPF can be sufficiently regenerated in this state, the valve control unit performs control to maintain the set pressure P [MPa] of the electromagnetic proportional relief valve 22 at the current set pressure or to lower the set pressure.

  On the other hand, when L <L0, the insufficient output L1 [kw] is calculated by L1 = L0−L, and control is performed to increase the set pressure P of the electromagnetic proportional relief valve 22 so that an output of L1 is generated. Do. Here, when the capacity of the DPF regeneration hydraulic pump 17 is q [cc / rev], the flow rate Q [L / min] of the DPF regeneration hydraulic pump 17 is Q = q × N. In order to generate the minute output, the set pressure of the electromagnetic proportional relief valve 22 is adjusted so that the value of P obtained from P1 = 60 × L1 / Q from L1 = P × Q / 60. Thereby, the output of the engine 11 can be set to the set output L0 for performing the regeneration of the DPF, and the automatic regeneration of the DPF can be performed.

  In this way, when the DPF is automatically regenerated, the current output of the engine 11 is compared with the set output, and the work circuit such as the main pumps 12 and 13 is in some work, and the current output of the engine 11 is If the output is higher than the set output, the current output of the engine 11 is sufficient to regenerate the DPF. Therefore, by maintaining or lowering the set pressure of the electromagnetic proportional relief valve 22, Even if the automatic regeneration of the DPF starts, no new load is applied to the engine. Therefore, even if the automatic regeneration of the DPF starts during the work, the work is adversely affected, or an excessive load is applied to the engine 11 and the fuel. Consumption does not increase.

  When the current output of the engine 11 is lower than the set output, the set pressure of the electromagnetic proportional relief valve 22 is calculated based on the current output of the engine 11 and the set output in order to increase the current output of the engine 11 to the set output. By controlling the electromagnetic proportional relief valve 22 so that the calculated set pressure is obtained, the DPF can be automatically regenerated without increasing the output of the engine 11 more than necessary, and the fuel consumption can be increased. Can be suppressed.

  Further, when the work using the work circuit such as the main pumps 12 and 13 starts during the automatic regeneration of the DPF, the output of the engine 11 becomes high, and the current output of the engine 11 exceeds the set output. As described above, the valve controller performs control to lower the set pressure of the electromagnetic proportional relief valve 22, so that the output of the engine 11 can be used efficiently for working various actuators. Increase in quantity can be suppressed.

  Further, since the DPF regeneration hydraulic pump 17 is provided separately from the working pumps and the hydraulic circuit is also independent, the pressure of the working hydraulic circuit is maintained even when a load is applied to the DPF regeneration hydraulic pump 17. Will not rise. Therefore, even if the automatic regeneration of the DPF is performed, the horsepower control does not act on the main pumps 12 and 13, and the flow rate of the working pump is reduced and the working speed is not lowered.

  Further, by returning the hydraulic oil discharged from the DPF regeneration hydraulic pump 17 to the tank 20 through the oil cooler 19, it is possible to effectively utilize the DPF regeneration hydraulic pump 17 when the DPF is not regenerated. .

  3 and 4 show a second embodiment of the hydraulic unit of the present invention. FIG. 3 is a hydraulic circuit diagram of the main part, and FIG. 4 is a block diagram of the pump displacement control means. In the following description, the same components as those of the hydraulic unit shown in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In this embodiment, in addition to the pumps 12, 13, 14, 15, and 16 used for work, a DPF regeneration variable displacement hydraulic pump 31 is provided for regeneration of the DPF, and the DPF regeneration variable displacement pump is used. On the discharge side of the hydraulic pump 31, a DPF regeneration circuit 33 connected to the oil tank 20 via a relief valve 32 with an unload function and the oil cooler 19 is provided.

  Also, as a control means, a pump capacity control means for receiving information on the rotational speed information 25a and torque information 25b of the engine 11 from the engine controller (ECU) 25 and controlling the capacity of the DPF regeneration variable displacement hydraulic pump 31; A controller 34 having a relief valve control means for switching the relief valve 32 with the unload function between an unloaded state and an operating state is provided.

  During normal work in which the DPF is not regenerated, the relief valve 32 with the unload function is switched to the unload state. Therefore, regardless of the capacity of the DPF regeneration variable displacement hydraulic pump 31 and the operating state of the engine 11, the hydraulic fluid discharged from the DPF regeneration variable displacement hydraulic pump 31 has almost no resistance and has a relief with an unload function. It passes through the valve 32, passes through the oil cooler 19, and is returned to the oil tank 20. That is, also in the present embodiment, the DPF regeneration circuit 33 from the DPF regeneration variable displacement hydraulic pump 31 functions as an oil cooling circuit for cooling the hydraulic oil.

  When the DPF automatic regeneration starts due to the pressure increase of the DPF upstream exhaust gas system or the continuation of the light load operation, the controller 34 obtains the engine speed information 25a and torque information 25b from the engine controller 25 in the same manner as described above. Receive and perform arithmetic processing. When the current output of the engine 11 exceeds the set output, the relief valve 32 with the unload function is controlled to maintain the unload state. At this time, the capacity of the DPF regeneration variable displacement hydraulic pump 31 is arbitrary, and can be set to an appropriate capacity for obtaining a flow rate according to the temperature of the hydraulic oil or the state of the oil cooler 19, for example.

  When the current output of the engine 11 is lower than the set output, the relief valve control means of the controller 34 outputs an operation signal to the solenoid (SOL-1) 32a of the relief valve 32 with the unload function to unload the function. With the attached relief valve 32 in an operating state, a certain resistance is given to the flow of hydraulic oil, and the pump capacity control means of the controller 34 is variable for DPF regeneration so that an output of L1 is generated in the engine as described above. A signal for adjusting the capacity of the displacement hydraulic pump 31 is output to the solenoid (SOL-1) 31a. The load increase L1 to the engine is obtained from the above formula, L1 = P × Q / 60 = P × q × N / 60, and the required capacity q is obtained as q = 60 × L1 / (P × N). Can do.

  Therefore, also in this embodiment, when the DPF is automatically regenerated, the hydraulic valve in operation is adversely affected by controlling the relief valve 32 with the unload function and the variable displacement hydraulic pump 31 for regenerating the DPF. Therefore, the engine can be operated at the set output and the increase in fuel consumption can be minimized.

  The use of the hydraulic unit of the present invention is arbitrary, and the number of hydraulic pumps is also arbitrary. The control valve of the oil cooling circuit may be set to open when the temperature of the hydraulic oil rises. Further, the controller may perform control such as adjusting the set pressure of the electromagnetic proportional relief valve until L = L0 or increasing / decreasing the capacity of the DPF regeneration variable displacement hydraulic pump.

DESCRIPTION OF SYMBOLS 11 ... Diesel engine 12, 13 ... Main pump, 14, 15, 16 ... Sub pump, 17 ... DPF regeneration hydraulic pump, 18 ... Control valve, 19 ... Oil cooler, 20 ... Oil tank, 21 ... Oil cooling circuit, 22 ... Electromagnetic proportional relief valve, 22a ... Solenoid, 23 ... DPF regeneration circuit, 24 ... Controller, 25 ... Engine controller (ECU), 25a ... Revolution information, 25b ... Torque information, 31 ... Variable displacement hydraulic pressure for DPF regeneration Pump 31a Solenoid 32 Relief valve with unload function 32a Solenoid 33 DPF regeneration circuit 34 Controller

Claims (4)

  In a hydraulic unit that drives a hydraulic pump by a diesel engine controlled by an engine controller and supplies hydraulic oil to an actuator, a DPF regeneration hydraulic pump that is driven by the diesel engine is provided, and a discharge of the DPF regeneration hydraulic pump is provided. And a relief valve control means for adjusting the set pressure of the electromagnetic proportional relief valve on the basis of a signal from the engine controller, while connecting the side to the oil tank via an electromagnetic proportional relief valve and an oil cooler. Features hydraulic unit.   The relief valve control means calculates the current engine output from the engine information receiving unit that receives information on the engine speed and torque from the engine controller, and calculates the current engine output from the received speed and torque. Is compared with the preset engine output required for DPF regeneration, and when the current output is lower than the set output, the set pressure of the electromagnetic proportional relief valve is increased, 2. The hydraulic unit according to claim 1, further comprising a valve control unit configured to maintain or reduce a set pressure of the electromagnetic proportional relief valve when a current output is high.   In a hydraulic unit that drives a hydraulic pump with a diesel engine controlled by an engine controller and supplies hydraulic oil to an actuator, a variable displacement hydraulic pump for DPF regeneration driven by the diesel engine is provided, and the DPF regeneration variable The discharge side of the displacement hydraulic pump is connected to the oil tank via a relief valve with an unload function and an oil cooler, and the capacity of the variable displacement hydraulic pump for DPF regeneration is determined based on a signal from the engine controller. A hydraulic unit comprising: pump capacity control means for controlling; and relief valve control means for switching the relief valve with an unload function between an unloaded state and an operating state.   The pump capacity control means includes an engine information receiving unit that receives information on the engine speed and torque from the engine controller, calculates the current engine output from the received speed and torque, and calculates the calculated current engine Is compared with the preset engine output required for DPF regeneration, and when the current output is lower than the preset output, the capacity of the DPF regeneration variable displacement hydraulic pump is increased and set. A pump capacity control unit that maintains or reduces the capacity of the DPF regeneration variable displacement hydraulic pump when the current output is higher than the output, and the relief valve control means When the output is high, the relief valve with unload function is unloaded, and the current output is low compared to the set output Hydraulic unit according to claim 3, characterized in that the operating state of the relief valve with unloading function.

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