JP4557205B2 - Control equipment for hydraulic equipment - Google Patents

Description

  The present invention relates to a control apparatus for hydraulic equipment, and more particularly to a control apparatus for hydraulic equipment used in construction machines such as hydraulic excavators.

  In general, as shown in FIG. 3, a construction machine such as a hydraulic excavator includes a lower traveling body 50, an upper swing body 51, and a work machine 52 connected to the upper swing body 51. The work machine 52 includes a boom 53 protruding from the upper swing body 51, an arm 54 connected to the boom 53, a bucket 55 attached to the arm 54, and the like. The boom 53 swings by driving the boom cylinder mechanism 56, the arm 54 swings by driving the arm cylinder mechanism 57, and the bucket 55 swings by driving the bucket cylinder mechanism 58. At this time, each cylinder mechanism is driven by hydraulic pressure. That is, the hydraulic equipment to be used includes a hydraulic pump and an engine that drives the hydraulic pump, and the cylinder mechanisms that are actuators are driven by the driving of the hydraulic pump.

  By the way, when used in such a construction machine of a hydraulic excavator, work in which the hydraulic pump does not require maximum output (for example, light load work such as work machine turning work other than normal excavation work or single work only with a boom) There is. Therefore, in the past, it is optimal to perform load sensing control of the hydraulic pump in work that requires less oil than normal excavation work (such as work that uses a hydraulic breaker as an attachment instead of a bucket) There is a type in which an appropriate amount of oil is set and an engine that drives a hydraulic pump is driven at a rotational speed that reduces fuel consumption (see, for example, Patent Document 1).

That is, the target engine speed and the target engine torque are set by the target value setter, and the breaker operation and the like are performed with the target engine speed and the target engine torque so as to achieve the minimum fuel consumption rate.
Japanese Patent No. 3064574

  And in the thing of the said patent document 1, the control by which an engine is drive | operated by the minimum fuel consumption rate is set by the engine torque and engine speed which become the minimum fuel consumption rate on a horsepower curve, such as an engine. However, in the conventional engine, the output torque curve is unambiguously determined. Therefore, with such control, it is difficult to approach the central portion of the equal fuel consumption curve at which the minimum fuel consumption rate is obtained.

  By the way, at the time of work in a normal load state such as excavation work, as shown in a diagram (engine speed-torque diagram) having an engine speed axis and a torque axis in FIG. The intersection with the pump maximum absorption torque curve b is a matching point A which is the maximum horsepower absorbed by the pump. Therefore, there is a case where the pump absorption torque is limited when the operation pattern or hydraulic condition does not require the maximum horsepower for the work, and the maximum horsepower absorbed by the pump is lowered to the matching point B, thereby reducing fuel consumption.

  However, with the fuel consumption rate at the matching point B, the fuel consumption cannot be reduced so much. That is, in FIG. 4, c, d, e, f, and g are equal fuel consumption curves, the fuel consumption rate is c <d <e <f <g, and the matching point B is e. This is because it is located outside. In addition, h, i, j, k, and m each indicate an equal horsepower line, and the horsepower is h> i> j> k> m. N is a torque line when the pump absorption torque is limited to improve fuel efficiency.

  The present invention has been made to solve the above-mentioned conventional drawbacks, and an object of the present invention is to provide a control device for a hydraulic device capable of effectively improving fuel efficiency.

The control apparatus for hydraulic equipment according to claim 1 is a control apparatus for hydraulic equipment comprising a hydraulic pump 1, an engine 2 that drives the hydraulic pump 1, and an actuator that is driven by the engine 2. Engine control means 3 for controlling the output torque of the engine, pump control means 4 for controlling the absorption torque of the hydraulic pump 1, and an engine output torque curve passing through a region within the equal fuel consumption curve where the fuel consumption rate is minimized and where the fuel consumption is minimized. engine storage means 6 for forming a1 and pump storage means 7 for forming a pump absorption torque curve b1 passing through a region within the equal fuel consumption curve with the minimum fuel consumption , and the hydraulic pump 1 requires its maximum horsepower In the normal load state, the engine 2 and the hydraulic pump 1 are in a normal operation in which the maximum horsepower can be output, and the hydraulic pump 1 has the maximum horsepower. In the light load state that does not require the engine, the engine output torque curve a1 stored in the engine storage unit 3 and the pump absorption torque curve b1 stored in the pump storage unit 7 are obtained by the switching signal from the switching unit 8. Furthermore, the engine control means 3 is switched to an energy saving operation in which the output torque of the engine 2 is controlled and the absorption torque of the hydraulic pump 1 is controlled by the pump control means 4.

In the control apparatus for hydraulic equipment according to claim 1, in the light load state in which the hydraulic pump 1 does not require its maximum horsepower, the engine storage means (by a load work switch as an example) in response to a switching signal from the switching means 8 Thus, an energy-saving operation is performed in which the engine output torque curve a1 stored in 3 and the pump absorption torque curve b1 stored in the pump storage means 7 are obtained. For this reason, low fuel consumption operation in a light load state is possible.

In the control apparatus for hydraulic equipment according to claim 2, the engine storage means 6 forms a normal operation engine output torque curve a that outputs a maximum horsepower, and the pump storage means 7 outputs a normal operation pump absorption torque that outputs a maximum horsepower. A curve b is formed, and at the time of the normal operation, the engine operates so that the normal operation engine output torque curve a stored in the engine storage unit 3 and the normal operation pump absorption torque curve b stored in the pump storage unit 7 are obtained. A normal operation is performed in which the output torque of the engine 2 is controlled by the control means 3 and the absorption torque of the hydraulic pump 1 is controlled by the pump control means 4.

The control apparatus for hydraulic equipment according to claim 2 can perform a normal operation in which the engine 2 and the hydraulic pump 1 can output the maximum horsepower in a normal load state in which the hydraulic pump 1 requires the maximum horsepower. For this reason, in a normal load state, work such as excavation work can be performed with the maximum horsepower output, and fuel-efficient driving is possible.

The control apparatus for hydraulic equipment according to claim 3 is characterized in that the switching signal is transmitted by the operation of an operation lever that is operated in a light load state.

In the control apparatus for hydraulic equipment according to claim 3 , when this operation becomes a light load operation by operating the operation lever, a switching signal is transmitted, and the energy saving operation (energy saving pattern) and the normal load in the light load state are transmitted. Switching to normal operation (normal pattern) that enables maximum horsepower output in the state can be performed reliably.

The control apparatus for a hydraulic device according to a fourth aspect is characterized in that the switching signal is transmitted when the hydraulic pressure of the hydraulic pump 1 is lower than a set value.

In the control apparatus for hydraulic equipment according to the fourth aspect , by detecting the hydraulic pressure of the hydraulic pump 1, a switching signal is transmitted when the hydraulic pressure is lower than a set value, that is, when a light load state occurs. . For this reason, it is possible to reliably switch between the energy saving operation (energy saving pattern) in the light load state and the normal operation (normal pattern) that enables the maximum horsepower output in the normal load state.

According to the control system for a hydraulic device of claim 1, it is possible to lower fuel efficiency under light load conditions, it is possible to improve fuel efficiency.

According to the control system for a hydraulic device of claim 2, usually allowed load state, it is possible to perform excavation work or the like at the maximum horsepower output, yet it is possible to reduce the fuel efficiency operating. As a result, fuel-efficient driving is possible regardless of work patterns and hydraulic conditions.

According to the control device for hydraulic equipment of claim 3 or claim 4 , it is possible to surely switch between the energy saving operation in the light load state and the normal operation that enables the maximum horsepower output in the normal load state. Thereby, the construction machine equipped with this control device can achieve a very effective fuel efficiency improvement.

  Next, specific embodiments of the control apparatus for hydraulic equipment according to the present invention will be described in detail with reference to the drawings. FIG. 1 shows a simplified block diagram of a control apparatus for hydraulic equipment according to the present invention. The hydraulic device includes a hydraulic pump 1 and an engine 2 that drives the hydraulic pump 1, and is used for construction machines such as a hydraulic excavator. That is, the construction machine includes a lower traveling body, an upper swing body, and a work machine that is connected to the upper swing body. The work implement includes a boom protruding from the upper swing body, an arm connected to the boom, a bucket attached to the arm, and the like. The boom swings by driving the boom cylinder mechanism, the arm swings by driving the arm cylinder mechanism, and the bucket swings by driving the bucket cylinder mechanism. At this time, the cylinder mechanisms as actuators are driven by driving the hydraulic pump 1 of the hydraulic equipment.

  The hydraulic circuit of the hydraulic equipment includes an engine controller (engine control means) 3 that makes the output torque of the engine 2 variable, a pump controller (pump control means) 4 that adjusts the absorption torque of the hydraulic pump 1, Control means 5 for controlling the controllers 3, 4, engine storage means 6, pump storage means 7, switching means 8 for switching the output torque of the engine 2 and the absorption torque of the hydraulic pump 1 according to the work pattern, etc., engine A rotation speed sensor 10 for detecting the rotation speed of the output shaft is provided.

  When the maximum horsepower is not required for the work (light load state), there are a single operation state such as a single work of turning the work machine and a single work of lowering the boom, and a mixed operation state of turning of the work machine and lowering the boom. In such a case, a light load operation can be detected by various sensors by operating an operation lever (not shown) in a cab provided in the upper swing body, and a switching signal can be transmitted to the control means 5. . Moreover, the case where the maximum horsepower is not required for work is work or the like in which the hydraulic pressure of the hydraulic pump 1 is lower than a predetermined pressure (set value set in the design). For this reason, the hydraulic pressure of the hydraulic pump 1 is detected by a hydraulic pressure sensor (not shown), and a switching signal is transmitted to the control means 5 in a load state where the hydraulic pressure of the hydraulic pump 1 is lower than a predetermined pressure (set value). Can be. That is, it is possible to configure the switching means 8 that transmits a switching signal using an operation lever, a hydraulic sensor, or the like. A servo mechanism 11 is interposed between the pump controller 4 and the hydraulic pump 1. For this reason, the servo mechanism 11 is operated by a signal from the pump controller 4 in accordance with the rotational speed from the rotational speed sensor 10, and the angle of the swash plate 12 of the hydraulic pump 1 is adjusted to obtain the pump absorption torque. The upper limit line is set, and the absorption torque can be varied according to the set absorption torque line within a range not exceeding the upper limit line. In this case, it is possible to vary the engine output torque by changing the fuel injection amount while keeping the rotational speed constant by electronic control or the like.

  Next, control by this control device will be described. First, at the time of work in a normal load state such as excavation work other than the light load work described above, no switching signal is transmitted from the switching means 8 to the control means 5, and the engine controller 3 and the pump controller 4 The hydraulic pump 1 is controlled so that the maximum horsepower can be output. That is, in the engine storage means 6, the engine maximum output torque curve (normal operation engine output torque curve) a in the diagram (engine speed-torque diagram) having the engine speed axis and the torque axis in FIG. The pump storage means 7 forms a pump maximum absorption torque curve (normal operation pump absorption torque curve) b in the above diagram. Then, in the normal load state such as excavation work, the engine operates so that the normal operation engine output torque curve a stored in the engine storage unit 6 and the normal operation pump absorption torque curve b stored in the pump storage unit 7 are obtained. The control means 3 controls the output torque of the engine 2 and the pump control means 4 controls the absorption torque of the hydraulic pump 1.

In this case, the intersection of the normal operation engine output torque curve a and the normal operation pump absorption torque curve b is a matching point A that is the maximum horsepower absorbed by the hydraulic pump 1. In FIG. 2, c, d, e, f, and g are equal fuel consumption curves, and the fuel consumption rate is c <d <e <f <g. For this reason, the fuel efficiency minimum point at which the fuel consumption rate is minimized is formed within the above-mentioned c constant fuel consumption curve (region within the uniform fuel consumption curve c with the minimum fuel consumption) . Moreover, h, i, j, k, and m each show an equal horsepower line, and the horsepower is h>i>j>k> m. In addition, n is the torque line shown in FIG. 4 and is a line that limits the pump absorption torque to improve fuel efficiency.

Next, a switching signal is transmitted from the switching means 8 when the operation pattern or hydraulic conditions do not require the maximum horsepower for the operation, that is, in a light load state, and the engine controller 3 causes the engine output torque curve (normally operated engine). the output torque curve) a, with varying as a1 fuel consumption rate through the region of the equal fuel consumption curve c minimum and ing at pump controller 4, pump absorption torque curve (normal operation pump absorption torque The curve (b) is changed like b1 passing through the fuel efficiency minimum point. As a result, the matching point A1 between the engine output torque curve a1 and the pump absorption torque curve b1 on the torque diagram with respect to the engine speed is brought close to the fuel efficiency minimum point, and energy saving operation is performed. That is, a1 is an engine output torque curve passing through the equal fuel consumption curve c, and b1 is a pump maximum absorption torque curve passing through the equal fuel consumption curve c. Therefore, the engine storage torque curve a1 is formed by the engine storage means 6, and the pump absorption torque curve b1 is formed by the pump storage means 7. Then, in the light load state, the control means 5 instructs the engine controller 3 so that the stored engine output torque curve a1 is obtained, and the engine output torque is changed and stored by the engine controller 3. The pump controller 4 is instructed by the control means 5 so that the pump absorption torque curve b1 is obtained, and the pump absorption torque is changed by the pump controller 4.

  In the case shown in FIG. 2, the matching point between the engine output torque curve a1 and the pump absorption torque curve b1 is A1, and it can be seen that fuel efficiency can be improved. On the other hand, when the maximum horsepower absorbed by the hydraulic pump 1 is lowered to the matching point B by limiting the pump absorption torque as in the past, the fuel consumption rate at the matching point B achieves much improvement in fuel consumption. Can not. As described above, even if the maximum horsepower absorbed by the hydraulic pump 1 is the same, if the energy saving operation is performed by the control of the control device, the engine output torque and the pump absorption torque are obtained at a place where the efficiency is higher than the fuel efficiency characteristics of the engine 2. Matching can be achieved and fuel consumption can be reduced.

  According to the above control device, it is possible to perform matching at a place where the fuel efficiency of the engine 2 is good by controlling both the engine output torque and the pump absorption torque. Thereby, fuel consumption improvement can be achieved. Further, since the energy saving operation of the control is automatically performed in a light load state where the hydraulic pump 1 does not require the maximum horsepower, a low fuel consumption operation in the light load state can be achieved.

  Further, by providing the switching means 8 and the like, it is possible to perform an energy saving operation in a light load state and perform a normal operation in which the engine 2 and the hydraulic pump 1 can output a maximum horsepower in a normal load state. As a result, fuel-efficient driving is possible regardless of work patterns and hydraulic conditions. Further, when this operation is a light load operation by operating the operation lever, a switching signal is transmitted, or when the oil pressure is lower than the set value by detecting the oil pressure of the hydraulic pump 1, that is, When a light load condition is reached, a switching signal is sent, so switching between energy-saving operation under light load conditions (energy-saving pattern) and normal operation that allows maximum horsepower output under normal load conditions (normal pattern) Can be performed reliably. This makes it possible to reliably switch between energy-saving operation under light load conditions and normal operation that enables maximum horsepower output under normal load conditions. Construction machines equipped with this control device are extremely effective in improving fuel efficiency. Can be achieved.

  By the way, in the above control, the engine output torque curve is switched from a to a1, and the pump absorption torque curve is switched from b to b1. It may be. Further, the engine output torque curve and the pump absorption torque curve may be variable within a set range. In this case, the engine output torque curve and the pump absorption torque curve can be automatically changed stepwise or continuously variable between the set ranges by a work pattern or work hydraulic pressure. Thereby, on the engine speed-torque diagram (matching characteristic diagram) shown in FIG. 2, the locus of the matching point can be drawn so as to be the best in terms of the fuel consumption characteristics of the engine 2, and it is more effective. Fuel consumption can be improved.

  Further, if the matching point is changed in accordance with the fuel consumption characteristics of the engine 2, matching can be performed at a place where the fuel efficiency is better on the engine 2 side. Thereby, low fuel consumption driving can be achieved reliably.

  Although specific embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made within the scope of the present invention. For example, in the above-described embodiment, although used for a hydraulic excavator, various construction machines other than a hydraulic excavator can be applied to a machine in which hydraulic equipment other than the construction machine is used. .

It is a simplified block diagram which shows embodiment of the control apparatus of the hydraulic equipment of this invention. It is an engine speed-torque diagram of the hydraulic equipment. It is a simplified diagram of a construction machine. It is an engine speed-torque diagram of the conventional hydraulic equipment.

Explanation of symbols

  1..Hydraulic pump 2..Engine 3..Engine control means (engine controller) 4..Pump control means (pump controller) 6..Engine storage means 7..Pump storage means 8 .. Switching means, A1 .. matching point, a, a1 .. engine output torque curve, b, b1 .. pump absorption torque curve

Claims (4)

A control apparatus for hydraulic equipment, comprising a hydraulic pump (1), an engine (2) that drives the hydraulic pump (1), and an actuator that is driven by the engine (2). The engine control means (3) for controlling the output torque, the pump control means (4) for controlling the absorption torque of the hydraulic pump (1), and the region within the equal fuel consumption curve where the fuel consumption rate is minimized and within the minimum fuel consumption curve. Engine storage means (6) for forming the engine output torque curve (a1) and pump storage means (7) for forming the pump absorption torque curve (b1) passing through the region within the equal fuel consumption curve with the minimum fuel consumption. In the normal load state in which the hydraulic pump (1) requires its maximum horsepower, the engine (2) and the hydraulic pump (1) are set to a normal operation enabling the maximum horsepower output, In a light load state where the hydraulic pump (1) does not require its maximum horsepower, the engine output torque curve (a1) stored in the engine storage means (3) and the pump are switched by a switching signal from the switching means (8). Control of the output torque of the engine (2) by the engine control means (3) and the hydraulic pump (4) by the pump control means (4) so that the pump absorption torque curve (b1) stored in the storage means (7) is obtained. 1. A control apparatus for hydraulic equipment, wherein the control is switched to energy saving operation for controlling absorption torque of 1). The engine storage means (6) forms a normal operation engine output torque curve (a) that outputs maximum horsepower, and the pump storage means (7) forms a normal operation absorption torque curve (b) that outputs maximum horsepower. In the normal operation, the normal operation engine output torque curve (a) stored in the engine storage means (3) and the normal operation pump absorption torque curve (b) stored in the pump storage means (7) are obtained. In addition, the engine control means (3) controls the output torque of the engine (2) and the pump control means (4) controls the absorption torque of the hydraulic pump (1). 1. Control device for hydraulic equipment. The control device for a hydraulic device according to claim 1 or 2 , wherein the switching signal is transmitted by an operation of an operation lever for driving in a light load state. The control device for hydraulic equipment according to claim 1 or 2 , wherein the switching signal is transmitted when the hydraulic pressure of the hydraulic pump (1) is lower than a set value.