JP2008144640A - Construction equipment warm-up equipment - Google Patents

Abstract

An engine cooling water temperature is increased at an early stage when the engine is started.
SOLUTION: A hydraulic pump 2 driven by an engine 1, a warm-up determination means 10-16 for determining whether or not a warm-up operation at the time of starting the engine is necessary, and a warm-up operation is required by the warm-up determination means 10-16. If it is determined, load application means 5, 7, 10 for increasing the load acting on the engine 1 via the hydraulic pump 2 are provided. The load applying means is a discharge pressure increasing means that is provided on the downstream side of the hydraulic pump 2 and increases the discharge pressure of the hydraulic pump 2.
[Selection] Figure 1

Description

  The present invention relates to a warm-up device for a construction machine that performs a warm-up operation when starting an engine.

  2. Description of the Related Art Conventionally, there has been known an apparatus that automatically performs a warm-up operation when starting an engine (see, for example, Patent Document 1). In the apparatus described in Patent Document 1, when the engine is started with the engine coolant temperature lower than room temperature, the engine speed is increased to the first target speed while keeping the pump tilt angle at a minimum. Thereafter, when the engine water temperature rises to room temperature or higher, the engine speed is increased to the second target speed and the pump tilt angle is increased to the maximum tilt angle.

Japanese Patent Laid-Open No. 7-4285

  However, since the device described in Patent Document 1 only rotates the engine at the first target rotational speed until the engine cooling water temperature reaches room temperature or higher, it takes time to warm up.

The warm-up device for a construction machine according to the present invention requires a warm-up operation by a hydraulic pump driven by an engine, a warm-up determination unit that determines whether or not a warm-up operation is required at the time of engine start, and a warm-up determination unit. When it is determined, load applying means for increasing the load acting on the engine via the hydraulic pump regardless of whether the engine speed has increased is provided.
The load applying means may be a discharge pressure increasing means that is provided on the discharge side of the hydraulic pump and increases the discharge pressure of the hydraulic pump.
The first hydraulic pump that discharges the drive pressure oil of the actuator and the second hydraulic pump that discharges the pilot pressure oil can be provided, and the load acting on the engine can be increased via the second pump.
Operation determination means for determining whether or not an operation for increasing the engine load is performed. When the operation determination means determines that this operation is being performed, the warm-up determination means performs warm-up operation. It is also possible to determine that the load is unnecessary and not to perform loading by the loading unit.

  According to the present invention, when it is determined that the warm-up operation is necessary, the load acting on the engine is increased via the hydraulic pump, so the warm-up time can be shortened.

Hereinafter, an embodiment of a warm-up device for a construction machine according to the present invention will be described with reference to FIGS.
FIG. 1 is a diagram showing a configuration of a warm-up device according to an embodiment of the present invention. This warm-up device is mounted on a construction machine such as a hydraulic excavator and automatically warms up when the engine is started in a cold region.

  The engine 1 is, for example, an engine with a turbo, and a hydraulic pump 2 is connected to the output shaft of the engine 1. The hydraulic pump 2 includes a main pump that supplies a driving pressure to an actuator such as a hydraulic cylinder and a hydraulic motor, and a pilot pump that supplies a pilot pressure to a hydraulic device (pilot valve) that is driven by the pilot pressure (see FIG. 1). Both of them are driven by the engine 1. The maximum discharge pressure of the main pump is larger than the maximum discharge pressure of the pilot pump. The main pump constitutes a high-pressure hydraulic circuit, and the pilot pump constitutes a low-pressure hydraulic circuit. The main pump is a variable pump whose pump tilt amount changes according to the driving pressure, and the pilot pump is a fixed pump whose tilt amount is fixed.

  FIG. 1 is a part of a low-pressure hydraulic circuit, and pressure oil (pilot pressure) from a hydraulic pump 2 is guided to a pilot valve 4 via a pipe line 3. In the present embodiment, an electromagnetic switching valve 5 is provided between the hydraulic pump 2 and the pilot valve 4, and a warm-up relief valve 7 is connected to the electromagnetic switching valve 5 via a pipe line 6. Although not shown, a pilot relief valve is connected to the pipe line 3 downstream of the electromagnetic switching valve 5, and the pilot pressure acting on the pilot valve 4 is limited by the pilot relief valve.

  The electromagnetic switching valve 5 is switched by a control signal from the controller 10. When the electromagnetic switching valve 5 is switched to the position A, the pressure oil from the hydraulic pump 2 acts on the relief valve 7. In this state, the discharge pressure of the hydraulic pump 2 is equivalent to the relief pressure defined by the relief valve 7, and a load corresponding to the relief pressure acts on the engine 1. The relief pressure of the relief valve 7 is set to a value larger than the relief pressure of the pilot relief valve. When the electromagnetic switching valve 5 is switched to the position A, the load acting on the engine 1 increases. On the other hand, when the electromagnetic switching valve 5 is switched to the position B, the pressure oil from the hydraulic pump 2 acts on the pilot valve 4.

  An air conditioning heater 8 is connected to the engine 1 via a cooling water pipe, and the start of the heating operation is instructed when the heater switch 11 is turned on. When the start of the heating operation is commanded, the air that is blown into the vehicle interior and the engine coolant are heat-exchanged by the heater 8, and warm air can be blown into the vehicle interior.

  In this case, if the engine cooling water temperature is sufficiently high, the air temperature can be raised to the target temperature by the heater 8, and favorable air-conditioning comfort can be obtained for workers in the cab. On the other hand, if the engine coolant temperature is low, the temperature of the air blown into the passenger compartment becomes lower than the target temperature, and air conditioning comfort deteriorates. Therefore, when the engine cooling water temperature is low, it is necessary to increase the heat generation amount of the engine 1 and increase the engine cooling water temperature at an early stage. In particular, in recent years, many engines with high thermal efficiency have been developed, and it is possible to work by driving a hydraulic pump with low fuel consumption. For this reason, the amount of heat absorbed from the engine into the engine cooling water tends to decrease, and it takes a long time to heat the cab. If the cab is being heated, the start of work is delayed. Therefore, in the present embodiment, the engine cooling water temperature is raised early as follows to shorten the warm-up operation time when working in a cold district or the like.

  The controller 10 includes a heater switch 11, a water temperature detector 12 for detecting the engine cooling water temperature, a pressure detector 13 for detecting the pressure of the engine oil, a gate lock switch 14 for detecting the operation position of the gate lock lever, A pedal operation amount detector 15 for detecting the operation amount of the accelerator pedal and a dial operation amount detector 16 for detecting the operation amount of the rotation speed setting dial provided in the driver's seat are connected. Signals from these are input to the controller 10, and predetermined processing is executed by the controller 10.

  The controller 10 sets a larger value as a rotation speed command value among the rotation speed according to the operation amount of the accelerator pedal and the rotation speed according to the operation amount of the rotation speed setting dial. For example, when the accelerator pedal is not operated and the rotational speed setting dial is operated to the minimum rotational position, the minimum engine rotational speed (low idle rotational speed) is set as the rotational speed command value.

  The gate lock lever is provided at the entrance of the driver's cab, and is a lever that can be operated between a lock release position protruding from the boarding / exiting path to the driver's seat and a lock position retracted from the boarding / exiting path. By operating the gate lock lever, a lock valve (not shown) is switched to allow or block the flow of pressure oil from the main pump to the actuator. Thus, when the driver leaves the driver's cab, the gate lock lever is operated to the locked position, so that the operation of the actuator is prohibited. When the driver enters the driver's cab and the gate lock lever is operated to the unlocked position, the operation of the actuator is permitted.

  FIG. 2 is a flowchart showing an example of the warm-up process executed by the controller 10. This flowchart starts when the controller 10 is turned on by turning on the start switch 17, and is repeated every predetermined time. In the initial state, the electromagnetic switching valve 5 is switched to the position B.

  First, in step S1, it is determined whether or not a warm-up mode start condition is satisfied. The warm-up mode is a mode for shortening the warm-up operation time when starting the engine in a cold region or the like, the heater switch 11 is turned on, the gate lock lever is operated to the lock position, and the rotation speed command value is When the low idle speed is commanded, the warm-up mode start condition is satisfied. In other cases, the warm-up mode start condition is not satisfied.

  If step S1 is affirmed, the process proceeds to step S2, and if denied, the process is terminated. In step S2, the engine speed is controlled to the low idle speed, and the low idle operation is performed. In step S3, it is determined whether the engine oil pressure P detected by the pressure detector 13 is equal to or greater than a predetermined value P1. This is a process for preventing the turbo turbine from being damaged due to the lack of lubricating oil when the engine speed is increased by the process (step S5) described later. If step S3 is affirmed, the process proceeds to step S4. If negative, the process returns to step S2.

  In step S4, it is determined whether the engine cooling water temperature T detected by the water temperature detector 12 is equal to or higher than a predetermined value T1. The predetermined value T1 is set to a temperature at which conditioned air suitable for heating can be blown into the vehicle interior. That is, if the engine coolant temperature is low, the air blown into the passenger compartment cannot be sufficiently heated by the heater 8, so in step S4, it is determined whether or not the conditioned air at a predetermined temperature can be blown.

  If step S4 is denied, the process proceeds to step S5, and if affirmed, the process is terminated. In step S5, the engine speed is increased from the low idle speed to a predetermined speed. The predetermined rotational speed is a rotational speed at which the engine 1 and the hydraulic pump 2 are not damaged. Furthermore, in step S4, a control signal is output to the electromagnetic switching valve 5, and the electromagnetic switching valve 5 is switched to position a. As a result, the pump relief pressure increases and the load acting on the engine 1 increases.

  In step S6, it is determined whether or not the warm-up mode is finished. In this case, (a) the engine coolant temperature T is equal to or higher than the predetermined value T1, (b) the heater switch 11 is turned off, (c) the operation to the release position of the gate lock lever, (d) the accelerator pedal operation or the rotation speed setting dial. If any condition of the engine speed increase command by the operation is satisfied, step S6 is affirmed and the warm-up process is terminated. On the other hand, when the above conditions (a) to (d) are not all satisfied, step S6 is denied and the process returns to step 5. When the warm-up process is completed, the electromagnetic switching valve 5 is switched to the position B, and the engine speed is set to a command value corresponding to the operation amounts of the accelerator pedal and the speed setting dial.

  The operation of the warm-up device according to the above embodiment is summarized as follows. When the work is performed in a state where the engine coolant temperature is equal to or lower than the predetermined value T1, the driver operates the gate lock lever to the lock position to enter the cab, and operates the engine key to start the engine. At this time, if the vehicle interior is to be waited without being heated until it is sufficiently heated, the gate lock lever is operated to the lock position, the accelerator pedal is not operated, and the rotation speed setting dial is operated to the minimum rotation speed. As a result, the warm-up mode starts and the engine 1 rotates at a low idle (step S2).

  At this time, when the engine oil pressure becomes equal to or higher than P1, the engine speed increases by a predetermined speed and the electromagnetic switching valve 5 is switched to the position (a) (step S5). As a result, the pump discharge pressure increases, the load acting on the engine 1 increases, and the amount of heat generated by the engine 1 increases. As a result, the engine coolant temperature can be raised early, and the cab can be heated in a relatively short time.

  When the engine coolant temperature becomes equal to or higher than the predetermined value T1, the warm-up mode is terminated, the electromagnetic switching valve 5 is switched to the position B, and the engine speed becomes the low idle speed. As a result, the warm-up operation is not performed more than necessary, and the work can be performed by guiding the pressure oil from the hydraulic pump 2 to the pilot valve 4.

  Even before the engine coolant temperature exceeds the predetermined value T1, the warm-up mode can be changed by operating the accelerator pedal or the speed setting dial to increase the speed command value or switching the gate lock lever to the release position. finish. Thereby, even if it does not wait until engine cooling water temperature becomes more than predetermined value T1, work can be performed by a driver's intention. In this case, since the driver manually performs an operation for increasing the load of the engine 1, it is not necessary to automatically perform the warm-up operation. When the heater switch 11 is turned off, it is not necessary to raise the engine coolant temperature for heating, so the warm-up mode is also terminated in this case.

According to the above embodiment, the following effects can be obtained.
(1) The engine rotational speed is increased from the low idle rotational speed by a predetermined rotational speed, and the hydraulic pump 2 is connected to the relief valve 7 by switching the electromagnetic switching valve 5 so as to increase the relief pressure and perform the warm-up operation. I made it. Thereby, the load which acts on the engine 1 rises, the engine coolant temperature can be raised early, and the cab can be heated in a short time during cold district work.

(2) Since it is not necessary to change the pump tilt angle to the large tilt side during the warm-up mode, seizure of the hydraulic pump can be prevented. That is, if the pump tilt angle is increased and the load of the engine 1 is increased, the oil temperature is low when the engine is started, so that the seizure of the pump becomes a problem. In order to prevent this, if the pump tilt angle is kept at the minimum tilt angle until the oil temperature rises, the engine coolant temperature cannot be raised early and the warm-up operation will be prolonged. In this regard, in the present embodiment, since the load is applied to the engine 1 by increasing the pump relief pressure, there is no need to change the pump tilt angle, and the problem of seizure does not occur. Since the hydraulic pump 2 with fixed pump tilt can be used, the application object is also wide.

(3) Since the load of the engine 1 is increased via the pilot hydraulic pump 2, the hydraulic circuit is a low-pressure circuit, and the relief valve 7 can be easily incorporated.
(4) The warm-up mode is terminated when the accelerator pedal depressing operation or the gate lock lever release position operation is detected, so there is no need to continue the warm-up operation more than necessary. You can start working.

  In the above embodiment, the relief valve 7 is provided downstream of the hydraulic pump 2 to increase the pump discharge pressure and increase the load acting on the engine 1. However, for example, instead of the relief valve 7, a throttle is used. It may be provided to increase the pump discharge pressure, and the discharge pressure increasing means is not limited to that described above. As long as a load is applied to the engine 1 regardless of whether or not the engine speed has increased, any load applying means may be used. For example, a dummy pump may be driven by the engine 1 to apply the load to the engine 1. Good. A load may be applied to the engine 1 by changing the pump tilt angle.

  Although the engine speed is increased simultaneously with the switching of the electromagnetic switching valve 5 (step S5), the load of the engine 1 may be increased without increasing the engine speed. When the engine oil pressure P becomes equal to or higher than the predetermined value P1, the electromagnetic switching valve 5 is switched to the position A. However, this processing is not necessarily required except for an engine with a turbo, and electromagnetic switching is performed simultaneously with the start of the warm-up mode. The valve 5 may be switched to position a. Although the engine speed is commanded by operating the accelerator pedal and the speed setting dial, the engine speed may be commanded by other operations.

  When the heater switch 11 is turned on, the gate lock lever is operated to the locked position, the low idle rotational speed is commanded as the rotational speed command value, and the engine coolant temperature is lower than the predetermined value T1, warm-up operation is required. Although determined, the configuration of the warm-up determination means is not limited to this. Further, although the operation for increasing the load of the engine 1 is determined based on the operation to the release position of the gate lock lever and the presence or absence of the operation of the accelerator pedal or the rotation speed setting dial, the operation determination means is not limited to this. While the main pump (first hydraulic pump) and the pilot pump (second hydraulic pump) are driven by the engine 1 and the engine 1 is loaded via the pilot pump, the load is loaded via the main pump. You may make it apply, and you may make it apply a load from both a main pump and a pilot pump. That is, as long as the features and functions of the present invention can be realized, the present invention is not limited to the warm-up device of the embodiment.

The figure which shows the structure of the warming-up apparatus which concerns on embodiment of this invention. The flowchart which shows an example of the process performed with the controller of FIG.

Explanation of symbols

2 Hydraulic pump 5 Electromagnetic switching valve 7 Relief valve 10 Controller 11 Heater switch 12 Water temperature detector 14 Gate lock switch 15 Pedal operation amount detector 16 Dial operation amount detector

Claims (4)

A hydraulic pump driven by an engine;
A warm-up determination means for determining whether or not a warm-up operation is required at the time of engine start;
Load determination means for increasing the load acting on the engine via the hydraulic pump regardless of whether the engine speed increases or not when the warm-up determination means determines that warm-up operation is necessary. A warm-up device for construction machinery. A hydraulic pump driven by an engine;
A warm-up determination means for determining whether or not a warm-up operation is required at the time of starting the engine;
When it is determined by the warm-up determination means that a warm-up operation is necessary, load applying means for increasing the load acting on the engine via the hydraulic pump is provided,
The warming device for a construction machine, wherein the load applying means is a discharge pressure increasing means that is provided on a discharge side of the hydraulic pump and increases a discharge pressure of the hydraulic pump. In the warming-up apparatus of the construction machine of Claim 1 or 2,
The hydraulic pump has a first hydraulic pump that discharges drive pressure oil of an actuator, and a second hydraulic pump that discharges pilot pressure oil,
The warming device for a construction machine, wherein the load applying means increases a load acting on the engine via the second pump. In the warming-up apparatus of the construction machine of any one of Claims 1-3,
Operation determining means for determining whether or not an operation for increasing the engine load is being performed;
The warm-up determining means determines that the warm-up operation is unnecessary when the operation determining means determines that the operation is being performed, and does not perform loading by the load applying means. Machine warm-up device.

Images