JP2014196037A - Hybrid drive device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a parallel type hybrid drive device which flexibly controls charging of a battery according to a load of a work machine.SOLUTION: A hybrid drive device includes: an engine; a filter part; a generator; a battery; a motor; and a transmission part. The filter part is disposed in an exhaust passage of the engine and purifies an exhaust gas. The generator generates electric power by a driving force of the engine. The battery is charged by the generator generating the electric power. The motor is driven by the electric power generated by the generator or the electric power charged in the battery. The transmission part transmits the driving force of the engine and a driving force of the motor for at least driving a work machine. The hybrid drive device performs charging speed increase control, in which the driving force transmitted from the engine to the generator is increased, when a load of the work machine is equal to or lower than a predetermined value.

Description

  The present invention relates to a parallel type hybrid drive device mounted on a work vehicle such as a tractor.

  Conventionally, a hybrid drive device including both an engine and a motor is known. Moreover, in a work vehicle equipped with a work machine (loader, rotary, etc.), a hybrid drive device may be employed to move the work vehicle or drive the work machine.

  Here, a series type and a parallel type are known as the hybrid type driving device. The series type is a hybrid drive device that uses the driving force of the engine for power generation and moves the work vehicle or drives the work machine only by the driving force of the motor. The parallel type is a hybrid type driving device that generates power by the driving force of the engine and moves the work vehicle or drives the work machine by the driving force of both the engine and the motor.

  Moreover, as an engine which comprises a hybrid type drive device, not only a gasoline engine but a diesel engine is used. A diesel particulate filter (hereinafter, DPF) is disposed in the diesel engine. The DPF collects particulate matter (hereinafter, PM) with a filter or the like. When the amount of PM collected by the DPF exceeds a predetermined value, it is necessary to increase the temperature in the DPF and remove the PM.

  Patent Documents 1 and 2 disclose a parallel type hybrid drive device for a work vehicle.

  Patent Document 1 discloses a hybrid drive device including a generator motor that can exhibit both functions of a generator and a motor. The hybrid drive device is configured to cause the generator motor to function as a generator when the load on the work machine is equal to or less than a predetermined value.

  Patent Document 2 discloses a hybrid drive device that performs charging when the amount of electricity stored in the battery is low, and heats the DPF with a heater when the amount of electricity stored in the battery is greater than or equal to a predetermined value. Thereby, even if it is a case where PM cannot be removed only by the heat from the engine, PM can be removed by assisting the heating of the DPF with the heater. Note that Patent Document 2 discloses a configuration in which a generator and a motor are separately provided.

  Patent Document 3 discloses an engine device that can execute forced regeneration control and forced low-speed control. The forced regeneration control is control for removing PM by increasing the temperature of the DPF by rotating the engine at a high speed. The forced low rotation control is control for realizing low fuel consumption and low noise by reducing the engine speed when the work machine is not loaded.

JP 2011-127534 A JP 2012-137028 A JP 2011-17256 A

  However, the generator motor of Patent Document 1 can only perform selective control of functioning as a generator or functioning as a motor. On the other hand, the load of the work machine, the charge amount of the battery, and the accumulation amount of PM take continuous values. Therefore, the hybrid drive device 20 of Patent Document 1 cannot perform flexible control according to the situation.

  Further, in Patent Document 2, a method is used in which the DPF is heated by a heater when the stored amount of the battery is equal to or greater than a predetermined value. However, since this method consumes the battery and removes the DPF, the energy efficiency may be reduced depending on the situation. Moreover, in patent document 2, the technique which controls charge according to the load of a working machine is not disclosed.

  Patent Document 3 is an invention of a normal diesel engine that is not a hybrid type.

  The present invention has been made in view of the above circumstances, and a main object of the present invention is to provide a parallel-type hybrid drive device that flexibly controls the charging of a battery in accordance with the load of the work machine.

Means and effects for solving the problems

  The problems to be solved by the present invention are as described above. Next, means for solving the problems and the effects thereof will be described.

  According to an aspect of the present invention, a hybrid drive device having the following configuration is provided. That is, the hybrid drive device includes an engine, a filter unit, a generator, a battery, a motor, and a transmission unit. The filter unit is disposed in the exhaust path of the engine and purifies exhaust gas. The generator generates power using the driving force of the engine. The battery is charged when the generator generates power. The motor is driven by electric power generated by the generator or electric power charged in the battery. The transmission unit transmits the driving force of the engine and the driving force of the motor at least for driving the work machine. When the load on the work implement is equal to or less than a predetermined value, charging speed increase control is performed to increase the driving force transmitted from the engine to the generator.

  Thereby, even when the load of the work implement is small, the load can be applied to the engine by increasing the charging speed. Therefore, PM accumulation in the filter portion can be prevented. Further, since the generator and the motor are configured separately, the motor can be driven even while the battery is being charged. Therefore, even when the load on the work machine is slightly increased during charging of the battery, charging can be continued by transmitting a part of the driving force of the engine to the transmission unit.

  The hybrid drive device preferably has the following configuration. That is, the hybrid drive device includes a low-rotation control unit that instructs low-rotation control to decrease the engine speed when the load on the work machine is equal to or lower than a predetermined value. The hybrid drive device performs the charging speed increase control when the low rotation control unit instructs the low rotation control.

  Thereby, since it can detect that the load of a working machine is below predetermined based on the instruction | indication of a low rotation control part, the effect of this invention is realizable, without adding a special sensor.

  In the hybrid drive device, it is preferable that the charging speed increase control is performed when it is detected that the load of the work implement is equal to or less than a predetermined value and the stored amount of the battery is equal to or less than a threshold value.

  As a result, the charging speed is increased only when the amount of power stored in the battery is small, so that a decrease in energy efficiency can be prevented.

  The hybrid drive device preferably has the following configuration. That is, a PM amount acquisition unit that acquires the PM amount of the filter unit or an estimated amount thereof is provided. When the PM amount acquired by the PM amount acquisition unit is greater than or equal to a predetermined value, the charging speed increase control is performed.

  As a result, the charging speed increase control is performed only when the amount of PM is large to increase the engine load, so that the number of times that noise is generated can be reduced.

  In the hybrid drive device, it is preferable that an increase amount of the driving force transmitted from the engine to the generator is determined according to the load of the work implement.

  Thereby, a charging speed can be raised as the load of a working machine becomes small. Therefore, charging can be performed by more effectively utilizing the driving force of the engine.

  In the hybrid drive device, it is preferable that the transmission unit transmits the driving force of the engine and the driving force of the motor for moving the work vehicle in addition to driving the work implement.

  Thereby, the effect of the present invention can be exhibited in the configuration in which the work vehicle is moved by the hybrid drive device.

A side view of a tractor. The block diagram which shows the structure which transmits the signal of a hybrid type drive device, electric power, a driving force, etc. FIG. The figure which shows DPF and an engine roughly. The block diagram which shows the relationship between the driving force of an engine and the electric power generation amount of a generator when the load of a working machine is below predetermined. The flowchart which shows the process which determines whether the driving force of an engine is allocated more to a generator. The block diagram which shows the modification which moves a vehicle body by the output of a hybrid type drive device.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a side view of a tractor (work vehicle).

  A tractor 1 as a work vehicle shown in FIG. 1 is configured to be able to perform various types of work by attaching various work machines (loader, rotary, etc.) to the front or rear. The tractor 1 includes a vehicle body 11, a front frame 12, a chassis frame 13, a front wheel 14, a rear wheel 15, and a cabin 17 as main components.

  A bonnet 16 is provided in the front portion of the vehicle body 11, and a hybrid drive device (details will be described later) including an engine and a motor is disposed inside the bonnet 16.

  Also, at the lower part of the tractor 1, there are a front frame 12 provided in a pair of left and right, and a chassis frame 13 provided in the same manner as a pair of left and right and extending rearward from the rear end portion of the front frame 12. Has been placed. The engine and the like are supported by these frames.

  The output of the hybrid drive device is first shifted by the transmission and then transmitted to the differential gear on the axle of the front wheel 14 and the differential gear on the axle of the rear wheel 15. The driving force transmitted to each differential gear is transmitted to the front wheel 14 and the rear wheel 15 via a transmission mechanism (not shown). With the configuration described above, the vehicle body 11 can be driven at a desired speed by driving the front wheels 14 and the rear wheels 15.

  Further, the output of the hybrid drive device is transmitted to a hydraulic pump or the like. Thereby, the above-mentioned working machine can be driven.

  Further, behind the hood 16, a cabin 17 is arranged for an operator to board and perform various operations of the tractor 1. For example, the cabin 17 is provided with a work implement operating lever for operating the work implement.

  Next, with reference to FIG.2 and FIG.3, the apparatus which comprises the hybrid type drive device 20 is demonstrated. FIG. 2 is a block diagram illustrating a configuration for transmitting signals, power, driving force, and the like of the hybrid drive device 20. FIG. 3 is a diagram schematically showing the DPF 22 and the engine 21.

  As shown in FIG. 2, the hybrid drive device 20 includes an engine 21, a DPF (filter unit) 22, a generator 23, a battery 24, an inverter 25, a motor 26, and a transmission unit 27. Yes.

  As shown in FIG. 3, the engine 21 includes an ECU (engine control unit) 21a, an intake manifold 41, a cylinder head 42, a common rail 43, an injector 44, an output shaft 45, and an exhaust manifold 46. ing.

  ECU21a acquires information from various sensors, and performs control about engine 21 based on these information.

  The intake manifold 41 is a pipe for introducing air sucked from the outside into the engine 21. The air introduced by the intake manifold 41 is sent into the cylinder of the cylinder head 42.

  Further, in the vicinity of the cylinder head 42, a common rail 43 and an injector 44 as a fuel injection mechanism are arranged. High pressure fuel is supplied to the common rail 43 from a fuel tank by a high pressure pump or the like. The common rail 43 supplies fuel to the injector 44 through a fuel supply pipe. The injector 44 is disposed for each cylinder, and injects fuel into the cylinder at a timing and an injection amount instructed by the ECU 21a.

  Thereby, a driving force can be generated by burning the fuel and moving the piston up and down. This driving force is transmitted to the generator 23 and the transmission unit 27 via the output shaft 45 and the like. The ECU 21a can control what percentage of the driving force of the engine 21 is transmitted to the generator 23 (distribution ratio).

  An exhaust manifold 46 is connected to the cylinder head 42. The exhaust manifold 46 sends the exhaust gas generated in the cylinder to the outside. The exhaust gas sent out by the exhaust manifold 46 is sent to the DPF 22 that purifies the exhaust gas.

  The DPF 22 includes an insertion port 51, a discharge port 52, filter cases 53 and 54, a diesel oxidation catalyst 55, a PM filter 56, and a differential pressure detector (PM amount acquisition unit) 57.

  The diesel oxidation catalyst 55 is installed in a cylindrical filter case 53, and reduces PM in the exhaust gas by an oxidation action by a catalyst such as palladium or platinum. The PM filter 56 collects PM in the exhaust gas by a filter body having a honeycomb structure.

  The differential pressure detector 57 includes differential pressure sensors 57a and 57b. The differential pressure sensor 57 a detects the pressure before passing through the diesel oxidation catalyst 55 and the PM filter 56. The differential pressure sensor 57 b detects the pressure after passing through the diesel oxidation catalyst 55 and the PM filter 56. The differential pressure detector 57 can estimate the amount of PM deposited on the DPF 22 based on the pressure difference between the differential pressure sensors 57a and 57b.

  The amount of PM deposited on the DPF 22 can also be estimated by means other than the differential pressure detector 57. For example, the amount of PM deposited on the DPF 22 can be estimated by performing a calculation based on the operation history of the engine 21.

  The generator 23 is connected to the output shaft 45 of the engine 21 as described above, and generates power with the driving force of the engine 21. The generator 23 can charge the battery 24 with the generated electric power or drive the motor 26.

  The inverter 25 converts the direct current of the battery 24 into an alternating current and supplies it to the motor 26. The inverter 25 can also control the output of the motor 26 by adjusting the magnitude of the alternating current.

  The motor 26 is rotated by electric power supplied from the inverter 25 or the like, and generates a driving force. The driving force generated by the motor 26 is transmitted to the transmission unit 27.

  A driving force generated by the engine 21 and a driving force generated by the motor 26 are input to the transmission unit 27. The transmission unit 27 combines these two driving forces to operate the hydraulic pump 31. The transmission unit 27 operates the hydraulic pump 31 to change the flow rate of the hydraulic oil supplied to the work machine 30 and drives the work machine 30. The hydraulic sensor 32 detects the pressure of the hydraulic oil supplied to the work machine 30.

  The hybrid drive device 20 is configured as described above. In the present embodiment, as indicated by a broken line in FIG. 2, the engine 21 (ECU 21a), the generator 23, and the inverter 25 are configured to be communicable with each other.

  For communication between the engine 21, the generator 23, and the inverter 25, for example, CAN (Controller Area Network) communication can be used. CAN communication is a known standard used for mutual communication between devices in automobiles and the like, and has features such as excellent noise resistance and high reliability.

  Next, the control performed when the load of the work machine 30 is not more than a predetermined value will be described.

  First, an outline of this control will be described with reference to FIG. FIG. 4 is a block diagram showing the relationship between the driving force of the engine 21 and the power generation amount of the generator 23 when the load on the work implement 30 is equal to or less than a predetermined value.

  In this control, when the load of the work machine 30 is equal to or less than a predetermined value, a large driving force of the engine 21 is allocated to the generator 23 to increase the charging speed (charging speed increasing control for increasing the charging current). As a result, even when the load on the work machine 30 is small, the engine 21 can be driven with a predetermined load (a load that can remove PM), so that the PM accumulated on the DPF 22 can be removed (PM is reduced). Can prevent deposition).

  In the present embodiment, the charging speed increase control is not performed according to only the load of the work machine 30, but is performed when other conditions are satisfied. Hereinafter, this will be described in detail with reference to FIG. FIG. 5A is a flowchart illustrating a process for determining whether to allocate a large amount of driving force of the engine 21 to the generator 23. FIG. 5B is a diagram for explaining the charged amount of the battery 24.

  The differential pressure detector 57 shown in FIG. 3 can estimate the amount of PM deposited on the DPF 22 as described above. The differential pressure detector 57 outputs the estimated PM amount to the ECU 21a of the engine 21. Then, the ECU 21a determines whether it is necessary to remove the PM in the DPF 22 based on the PM amount input from the differential pressure detector 57 (that is, whether the PM amount is greater than or equal to a predetermined value) (S101).

  When it is not necessary to remove PM in the DPF 22, it is not necessary to perform charge speed increase control, and thus the ECU 21a performs the process of S101 again after a predetermined time, for example.

  When it is determined that the PM in the DPF 22 needs to be removed, the ECU 21a determines whether or not the load on the work implement 30 is equal to or less than a predetermined threshold (S102). The ECU 21a makes this determination based on, for example, the hydraulic oil pressure acquired from the hydraulic sensor 32 (that is, the load of the work machine 30). This threshold value is determined based on whether or not the work implement 30 can be appropriately driven even if the driving force of the engine 21 is allocated to the generator 23 in a large amount.

  In addition, the method of acquiring the load of the work machine 30 is arbitrary, and can be changed as appropriate. For example, consider a case where the ECU 21a has a function as a low rotation control unit that performs low rotation control. The low rotation control is a control that realizes low fuel consumption and low noise by making the engine 21 rotate at low speed when the work machine 30 is not loaded.

  More specifically, the ECU 21a as the low-rotation control unit performs the low-rotation control based on, for example, the operation state of a lever that operates the work machine 30, whether low-rotation control is permitted by the user, or the like. Determine whether or not. For this reason, when the ECU 21a determines to perform the low rotation control, it is considered that the addition of the work machine 30 is small. Therefore, it can be acquired that the load of the work implement 30 is smaller than a predetermined value in accordance with the instruction of the low rotation control performed by the ECU 21a. Thus, the load of the work implement 30 can be acquired based on the presence / absence of the low rotation control instruction.

  Here, the generator 23 can detect the charged amount of the battery 24. The generator 23 detects the charged amount of the battery 24 (S201), and outputs it to the ECU 21a.

  The ECU 21a acquires the amount of electricity stored in the battery 24 from the generator 23, and determines whether or not the amount of electricity stored in the battery 24 is fully charged (S103). Here, the full charge is a case where the charged amount is larger than a predetermined threshold as shown in FIG.

  When the charged amount of the battery 24 is fully charged, there is no need to increase the charging speed. In this case, the ECU 21a performs the process of S101 again after a predetermined time, for example.

  The ECU 21a determines whether or not the load of the engine 21 is equal to or greater than a predetermined threshold when the amount of power stored in the battery 24 is not fully charged (S104). As this threshold, for example, a load that can remove PM in the DPF 22 can be set.

  When the load on the engine 21 is smaller than the predetermined threshold, the ECU 21a increases the load on the engine 21 to the threshold (to the extent that PM in the DPF 22 can be removed) (S105). Thereafter, the ECU 21a allocates more driving force of the engine 21 to the generator 23 (S106). Note that if the load of the engine 21 is equal to or greater than the predetermined threshold in the determination of S104, the driving force of the engine 21 is allocated to the generator 23 rather than via S105 (S106).

  Thereby, charging speed increase control can be performed only when necessary. The flowchart shown in FIG. 5A is an example. For example, in FIG. 5A, the charging speed increase control is performed when all the conditions of the PM amount, the load of the work machine 30, and the storage amount of the battery 24 are satisfied. Only the load of 30 may be performed as a condition, the load of the PM and the work machine 30 may be performed as a condition, or the load of the work machine 30 and the charged amount of the battery 24 may be performed as a condition.

  In S106, how much driving force is allocated to the generator 23 can be controlled based on various values. For example, the driving force can be allocated to the generator 23 more as the load of the work machine 30 is smaller. Further, as the amount of power stored in the battery 24 is smaller, more driving force can be allocated to the generator 23.

  Thereby, the charge amount can be flexibly adjusted according to the situation.

  Next, with reference to FIG. 6, the structure which moves the tractor 1 by the hybrid type drive device 20 is demonstrated. FIG. 6 includes a transmission 61, differential gears 62 and 64, and axles 63 and 65 in addition to the hybrid drive device 20 described above.

  The driving force generated by the engine 21 and the motor 26 of the hybrid drive device 20 is transmitted to the transmission device 61 via the transmission unit 27. The transmission 61 transmits this driving force to the differential gear 62 on the front wheel side and the differential gear 64 on the rear wheel side at a gear ratio specified by the operator. The differential gears 62 and 64 transmit this driving force to the axles 63 and 65, respectively. Accordingly, the tractor 1 can be moved by the hybrid drive device 20.

  As described above, the hybrid drive device 20 of the present embodiment includes the engine 21, the DPF 22, the generator 23, the battery 24, the motor 26, and the transmission unit 27. The DPF 22 is disposed in the exhaust path of the engine 21 and purifies the exhaust gas. The generator 23 generates power using the driving force of the engine 21. The battery 24 is charged when the generator 23 generates power. The motor 26 is driven by the power generated by the generator 23 or the power charged in the battery 24. The transmission unit 27 transmits the driving force of the engine 21 and the driving force of the motor 26 at least for driving the work machine 30. When the load on the work machine 30 is equal to or less than a predetermined value, the charging speed increase control is performed to increase the driving force transmitted from the engine 21 to the generator 23.

  Thereby, even if the load of the work machine 30 is small, the load can be applied to the engine 21 by increasing the charging speed. Accordingly, accumulation of PM in the DPF 22 can be prevented. Further, since the generator 23 and the motor 26 are configured separately, the motor 26 can be driven even when the battery 24 is being charged. Therefore, even when the load of the work implement 30 is slightly increased during the charging of the battery 24, the charging can be continued by transmitting a part of the driving force of the engine 21 to the transmission unit 27.

  In addition, the hybrid drive device 20 of the present embodiment includes an ECU 21a that instructs low rotation control for reducing the rotation speed of the engine 21 when the load of the work machine 30 is equal to or less than a predetermined value. The hybrid drive device 20 performs charge speed increase control when the ECU 21a instructs low rotation control.

  Thereby, since it can detect that the load of the working machine 30 is below predetermined based on the instruction | indication of ECU21a, the effect of this invention is realizable, without adding a special sensor.

  Further, the hybrid drive device 20 of the present embodiment performs charge speed increase control when it is detected that the load of the work machine 30 is equal to or less than a predetermined value and the amount of power stored in the battery 24 is equal to or less than a threshold value.

  As a result, the charging speed is increased only when the amount of power stored in the battery 24 is small, so that a decrease in energy efficiency can be prevented.

  Further, the hybrid drive device 20 of the present embodiment includes a differential pressure detector 57 that acquires the PM amount of the DPF 22 or the estimated amount thereof. When the amount of PM acquired by the differential pressure detector 57 is greater than or equal to a predetermined value, charge speed increase control is performed.

  Thereby, only when the amount of PM is large, the charging speed increase control is performed to increase the load of the engine 21, so that the number of times that noise is generated can be reduced.

  Further, in the hybrid drive device 20 of the present embodiment, the amount of increase in the driving force transmitted from the engine 21 to the generator 23 is determined according to the magnitude of the load on the work implement 30.

  As a result, the charging speed can be increased as the load on the work machine 30 decreases. Therefore, charging can be performed by more effectively using the driving force of the engine 21.

  The preferred embodiment of the present invention has been described above, but the above configuration can be modified as follows, for example.

  In FIG. 2 described above, the engine 21, the generator 23, and the inverter 25 are directly connected to each other. However, a separate control unit that performs overall control of the hybrid drive device 20 is provided, and through this control unit, Each may be connected. Moreover, the control part which controls the electric drive sides, such as the generator 23 and the inverter 25, is provided separately, and the structure which this control part communicates with ECU21a may be sufficient.

  The load of the work implement 30 may be determined based on the operation of the work implement operation lever arranged in the cabin 17 instead of the hydraulic sensor.

  Although the tractor network is configured by CAN, the present invention is not limited to this, and other types of networks may be used as long as the communication control unit of the tractor and each work machine are configured to communicate with each other.

  The hybrid drive device of the present invention can also be applied to a drive source of a work vehicle other than a tractor. Examples of work vehicles include agricultural machines such as combine and rice transplanters, and construction machines such as power shovels.

1 Tractor 20 Hybrid Drive Device 21 Engine 21a ECU (Low Rotation Control Unit)
22 DPF (filter part)
23 Generator 24 Battery 25 Inverter 26 Motor 30 Work implement 31 Hydraulic pump 32 Hydraulic sensor 57 Differential pressure detector (PM amount acquisition unit)

Claims (6)

An engine,
A filter unit disposed in an exhaust path of the engine and purifying exhaust gas;
A generator for generating power by the driving force of the engine;
A battery that is charged as the generator generates electricity;
A motor driven by the power generated by the generator or the power charged in the battery;
A transmission unit for transmitting the driving force of the engine and the driving force of the motor at least for driving the work machine;
With
A hybrid type driving apparatus that performs charging speed increase control for increasing a driving force transmitted from the engine to the generator when a load on the working machine is equal to or less than a predetermined value. The hybrid drive device according to claim 1,
A low-rotation control unit for instructing low-rotation control to reduce the engine speed when the load on the work machine is equal to or lower than a predetermined value;
The hybrid drive apparatus according to claim 1, wherein the charge speed increase control is performed when the low rotation control unit instructs the low rotation control. The hybrid drive device according to claim 1 or 2,
A hybrid drive device that performs the charging speed increase control when it is detected that the load of the work implement is equal to or less than a predetermined value and the stored amount of the battery is equal to or less than a threshold value. The hybrid drive device according to any one of claims 1 to 3,
A PM amount acquisition unit for acquiring the PM amount of the filter unit or the estimated amount thereof,
The hybrid drive device, wherein the charge speed increase control is performed when the PM amount acquired by the PM amount acquisition unit is greater than or equal to a predetermined value. The hybrid drive device according to any one of claims 1 to 4,
The hybrid drive apparatus according to claim 1, wherein an increase amount of the drive force transmitted from the engine to the generator is determined according to a load size of the work implement. A hybrid drive device according to any one of claims 1 to 5,
The transmission unit transmits the driving force of the engine and the driving force of the motor for driving the work vehicle in addition to driving the work machine.

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