Work vehicles

Abstract

Some combine harvesters control the regeneration operation of their exhaust gas purification system when the engine coolant temperature is maintained at a predetermined temperature. However, in cold regions or other areas with low ambient temperatures, the coolant temperature is also low, which presents a problem as the exhaust gas purification system's regeneration function cannot be properly utilized during operation. Therefore, this invention provides a work vehicle that allows the exhaust gas purification system's regeneration function to be properly utilized. [Solution] In a work vehicle equipped with an exhaust gas purification device 25a, an engine fan 24 for cooling the engine 16, and a water temperature sensor 26 for detecting the temperature of the engine coolant of the engine 16, the engine fan 24 can rotate in both forward and reverse directions, and the control device 19 drives the engine fan 24 in reverse when the temperature of the engine coolant is below a specified value to raise the temperature of the engine coolant.

Description

Technical Field

[0001] The present invention relates to a work vehicle such as a combine or a tractor.

Background Art

[0002] There is a combine that controls the regeneration operation of an exhaust gas purification device when the cooling water temperature of an engine is maintained at a predetermined temperature (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when the outside air temperature is low, such as in cold regions, the cooling water temperature is also low, so there is a problem that the regeneration function of the exhaust gas purification device cannot be exerted during driving.

[0005] Therefore, the present invention provides a work vehicle in which the regeneration function of an exhaust gas purification device can be appropriately exerted.

Means for Solving the Problems

[0006] The invention according to claim 1 is a work vehicle including an exhaust purification device 25a, an engine fan 24 that cools the engine 16, and a water temperature sensor 26 that detects the temperature of the engine cooling water of the engine 16, wherein the engine fan 24 can rotate forward and backward, and the control device 19 reversely drives the engine fan 24 when the temperature of the engine cooling water is below a specified value to raise the temperature of the engine cooling water.

[0007] According to the invention described in claim 1, the engine fan 24 is reversed to utilize the heat generated from the engine 16 to heat the engine coolant, thereby allowing the regeneration function of the exhaust gas purification device 25a to be properly performed.

[0008] The invention described in claim 2 is a work vehicle according to claim 1, wherein if the engine coolant temperature rises above a specified value while the engine fan 24 is rotating in reverse, the engine fan 24 is rotated from reverse to forward to draw in outside air and lower the engine coolant temperature.

[0009] According to the invention described in claim 2, if the engine coolant temperature rises above a specified value while the engine fan 24 is rotating in reverse, the engine fan 24 is rotated from reverse to forward to draw in outside air and lower the engine coolant temperature, thereby preventing the engine 16 from overheating and the engine oil temperature from rising.

[0010] The invention described in claim 3 is a work vehicle according to claim 1, wherein when the vehicle speed exceeds a specified vehicle speed while the engine fan 24 is rotating in reverse, when the sub-transmission lever 18a is in the travel position, or when the work lever 18b is in the drive-engagement position for the work devices 6 and 15, the engine fan 24 is rotated from reverse to forward to draw in outside air and lower the temperature of the engine coolant.

[0011] According to the invention described in claim 3, when the vehicle speed exceeds a specified vehicle speed while the engine fan 24 is rotating in reverse, when the sub-transmission lever 18a is in the travel position, or when the work lever 18b is in the drive-engagement position for the work devices 6 and 15, the engine fan 24 is rotated from reverse to forward to draw in outside air and lower the temperature of the engine coolant, thereby preventing the engine 16 from overheating and the engine oil temperature from rising. [Brief explanation of the drawing]

[0012] [Figure 1] This is a side view of a combine harvester according to an embodiment of the present invention. [Figure 2] This is a plan view of a combine harvester. [Figure 3]This is a rear view of the engine section. [Figure 4] This is a control block diagram. [Figure 5] This is a control flow diagram. [Modes for carrying out the invention]

[0013] Hereinafter, a combine harvester 1, which is one embodiment of the present invention, will be described with reference to the attached drawings. For the sake of ease of understanding, directions will be conveniently indicated as front, rear, right, and left from the operator's perspective; however, the configuration is not limited by these directions.

[0014] <Overall configuration of a combine harvester> As shown in Figures 1 and 2, the combine harvester 1 has a running gear 4 on the lower side of the chassis 2, with a pair of left and right crawler tracks 3 that travel on the soil surface. On the left and right sides of the chassis 2 are a threshing device 6, which is a working device for threshing and sorting the grain stalks that are carried and supplied by the feed chain, a paddy tank 7, which is a storage device for temporarily storing the grain, and a grain auger 8, which discharges the grain stored in the paddy tank 7 to the outside of the machine. A straw disposal device 9 is mounted on the rear end of the threshing device 6. The grain auger 8 raises and lowers when the auger lifting cylinder is operated to discharge the grain.

[0015] Furthermore, a harvesting device 15 is configured in front of the threshing device 6, which is suspended from the front end of the chassis 2 so that it can move up and down relative to the soil surface by a harvesting lifting cylinder. This device includes a grass-separating body 11 that separates unharvested grain stalks from the front end, a lifting unit 12 that raises the separated grain stalks, a cutting blade unit 13 that cuts the raised grain stalks, and a supply adjustment and conveying unit that scoops up the harvested grain stalks and adjusts the handling depth during conveyance before handing them over to the feed chain.

[0016] An operating device for controlling the operation of the combine 1 is provided at the upper rear side of the mowing device 15, and an operator's seat on which the operator sits is provided. A diesel engine 16 (hereinafter simply referred to as the engine) is mounted below this operator's seat, and the paddy tank 7 is arranged on the rear side. A cabin 17 covering the operating device and the operator's seat is provided, and these traveling devices 4, threshing device 6, mowing device 15, engine 16, cabin 17, etc. are provided on the chassis 2 of the combine.

[0017] The operating device includes a main shift lever for operating a main shift actuator that operates a hydrostatic continuously variable transmission for switching forward and backward movement and stop and main shift switching by the front and rear operation of the operator sitting on the operator's seat, a sub-shift lever 18a for operating a sub-shift actuator that switches a stepped sub-shift device provided in the transmission mechanism in the transmission, a left and right traveling actuator for operating the left and right side clutches and left and right side brakes of the left and right traveling crawlers 3, 3 by tilting operations to the left and right sides to perform left and right steering during straight travel and turning in various turning modes, a steering lever for operating the mowing lift cylinder by an operation in the front and rear direction to raise and lower the mowing device 15, a threshing lever 18b as a work lever for operating a threshing clutch actuator to turn on and off the drive of the mowing device 15 and the threshing device 6, an auger operation lever for moving the discharge auger 8 vertically by operating an auger lift cylinder and horizontally by operating a left and right turning actuator, and various operating tools such as an auger drive switching lever for operating an auger drive electromagnetic clutch that turns on and off the drive of the discharge auger 8 to discharge the grains in the paddy tank 7 outside the machine.

[0018] Also, a vehicle speed sensor 4a composed of a rotation sensor is provided in the drive system of the traveling device 4.

[0019] A monitor as a display device for displaying various information by receiving input information from the operating device and each sensor is provided at the front position of the operator's seat in the cabin 17, and a control device 19 for operating and controlling each part by receiving input information from the operating device and each sensor is provided at the lower position of the operating device.

[0020] <Engine 16 and its peripheral equipment> As shown in FIGS. 1 to 4, as an intake device for introducing outside air into the engine 16, a pre-cleaner 20 and an air cleaner 21 are connected in series, and coarse dust mixed in the sucked outside air is first removed by the pre-cleaner 20, and the outside air is guided to the air cleaner 21 to remove fine dust and supplied to the engine 16 through an intake pipe 21a.

[0021] And the hose 22 between the pre-cleaner 20 and the air cleaner 21 is arranged inside the machine body to the left of the right side surface 17a which is the right outer surface of the cabin 17, and a part of the intake port 20a of the pre-cleaner 20 is located outside the machine body to the right of the right side surface 17a of the cabin 17.

[0022] The hose 22 is arranged inside the machine body more than the right end of the operation seat in the cabin 17 on the right side of the machine body to prevent interference with obstacles.

[0023] The hose 22 bends the lower part on the air cleaner 21 side inward of the machine body so as not to interfere with the opening and closing of a radiator cover 23a that covers the right outer side of a radiator 23 located on the right outer side of the engine 16.

[0024] Therefore, while preventing the hose 22 from contacting an obstacle, it is possible to suck the traveling wind from the front instead of the hot air staying between the cabin 17 and the rice tank 7 into the pre-cleaner 20, and it is possible to prevent a decrease in the output of the engine 16.

[0025] Also, a cabin roof 17b of the cabin 17 protrudes outward to the right more than the side surface 17a of the cabin 17 main body, and the right end of the pre-cleaner 20 is on the left side (inside the machine body) more than the right end of the cabin roof 17b.

[0026] Therefore, although a part of the intake port 20a of the pre-cleaner 20 is located outside the machine body to the right of the right side surface 17a of the cabin 17, it is possible to prevent the pre-cleaner 20 from interfering with an obstacle by the cabin roof 17b.

[0027] Furthermore, the pre-cleaner 20 is positioned to the right and outside of the exhaust gas aftertreatment device, which consists of a diesel particulate filter 25a (hereinafter referred to as DPF) and an SCR 25b, as an exhaust gas purification device.

[0028] Therefore, the intake air of the pre-cleaner 20 is less affected by the hot air from the exhaust gas aftertreatment system, which consists of the DPF 25a and SCR 25b.

[0029] Furthermore, the pre-cleaner 20 is positioned so that it overlaps with the rear hatch 17c behind the control seat of the cabin 17 in the left-right direction.

[0030] Therefore, the rear hatch 17c can be opened to easily perform maintenance on the pre-cleaner 20.

[0031] The radiator 23 is located on the right outer side of the engine 16, and the engine fan 24 is mounted on the engine 16 side inside the aircraft.

[0032] The engine fan 24 is driven in forward and reverse directions by the fan motor 24a.

[0033] When the engine fan 24 is driven in the forward direction, outside air is drawn in through the dustproof net made of metal mesh of the radiator cover 23a to cool the radiator 23, lower the temperature of the engine coolant, and blow the air towards the engine 16 inside the aircraft to directly cool the engine 16, DPF 25a, and SCR 25b.

[0034] When the engine fan 24 is driven in reverse, it draws in air from the inside of the aircraft where the engine 16 is located, raising the temperature of the engine coolant in the radiator 23 with the hot air from the engine 16. This coolant is then discharged outside the aircraft through a dustproof net made of metal mesh of the radiator cover 23a, blowing away any dust and debris such as straw that may have accumulated on the dustproof net and preventing it from becoming clogged.

[0035] Furthermore, the radiator 23 is equipped with a water temperature sensor 26 for measuring the temperature of the engine coolant and an intake outside air temperature sensor 27 for measuring the temperature of the outside air drawn into the outside of the radiator 23, and the radiator cover 23a is equipped with an illuminance sensor 28a for measuring the illuminance on the outside and an illuminance sensor 28b for measuring the illuminance on the inside.

[0036] The measured values ​​from each sensor 26, 27, 28a, and 28b are input to the control device 19.

[0037] The exhaust gas aftertreatment system, consisting of DPF25a and SCR25b, purifies air pollutants in the exhaust gas from the engine 16.

[0038] The DPF25a collects particulate matter (hereinafter referred to as PM) and other particles in the exhaust gas. In this case, if the amount of PM collected by the DPF25a exceeds a specified amount, the exhaust resistance within the DPF25a increases, leading to a decrease in engine output. Therefore, the PM accumulated in the DPF25a is removed by raising the temperature of the exhaust gas, restoring the PM collection capacity of the DPF25a (regenerating the DPF25a).

[0039] Generally, a DPF25a houses a roughly cylindrical filter case within a heat-resistant metal casing, containing a diesel oxidation catalyst (such as platinum) and a soot filter in series. The diesel oxidation catalyst is positioned on the exhaust upstream side of the filter case, and the soot filter is positioned on the exhaust downstream side. The soot filter has a honeycomb structure with numerous cells partitioned by porous partitions capable of filtering exhaust gas.

[0040] The DPF25a is equipped with a differential pressure sensor as an example of a detection means for detecting the clogging state of the soot filter. The differential pressure sensor detects the pressure difference between the exhaust pressures on the upstream and downstream sides of the soot filter within the DPF25a (the differential pressure of the exhaust gas on the inlet and outlet sides).

[0041] Furthermore, since there is a specific relationship between the pressure difference between the exhaust pressures on the upstream and downstream sides of the DPF25a and the amount of PM accumulated in the soot filter, the amount of PM accumulated in the DPF25a is calculated based on the pressure difference detected by the differential pressure sensor. Based on the calculation result of the PM accumulation amount, forced regeneration control of the DPF25a is executed.

[0042] When exhaust gas passes through the diesel oxidation catalyst and soot filter, if the exhaust gas temperature exceeds the regeneration temperature (for example, approximately 250-300°C), the diesel oxidation catalyst oxidizes the NO (nitric oxide) in the exhaust gas to unstable NO2 (nitrogen dioxide). Then, the O (oxygen) released when NO2 reverts back to NO oxidizes and removes PM accumulated on the soot filter, thereby restoring the PM collection capacity of the soot filter. In other words, the DPF25a self-regenerates.

[0043] However, immediately after starting the engine 16 or in cold climates where the outside temperature is low, the temperature of the engine coolant in the radiator 23 is also low, which may prevent the DPF 25a from performing its regeneration function.

[0044] Therefore, in this embodiment, the following control is performed so that the regeneration function of the DPF25a can be properly utilized.

[0045] In other words, as shown in the control flowchart of Figure 5, when the measured value of the water temperature sensor 26 that measures the temperature of the engine coolant is below a specified value (for example, 40 degrees Celsius), the measured value of the vehicle speed sensor 4a (vehicle speed) is not above the specified vehicle speed (standard speed MAX), the sub-transmission lever 18a is not in the travel position, and the harvesting lever 18b is not in the position where the harvesting device 15 and the threshing device 6 are engaged (ON), the engine fan 24 is driven in reverse to draw air from inside the machine body where the engine 16 is located, raising the temperature of the engine coolant in the radiator 23 with the hot air from the engine 16 so that the regeneration function of the DPF 25a can be properly performed.

[0046] Therefore, by reversing the rotation of the engine fan 24, the heat generated from the engine 16 is used to heat the engine coolant, allowing the DPF 25a to perform its regeneration function properly and improving fuel efficiency.

[0047] Furthermore, if the water temperature sensor 26, which measures the temperature of the engine coolant, rises above a specified value (for example, 40°C) while the engine fan 24 is in reverse drive, if the vehicle speed sensor 4a measures above the specified vehicle speed (standard speed MAX), if the sub-transmission lever 18a is in the travel position, or if the threshing lever 18b is in the ON position for engaging the harvesting device 15 and the threshing device 6, the engine fan 24 is switched from reverse drive to forward drive to draw in outside air, cool the radiator 23 to lower the temperature of the engine coolant, and blow air towards the engine 16 inside the machine to directly cool the engine 16, DPF 25a and SCR 25b, thereby preventing the engine 16 from overheating and the engine oil temperature from rising.

[0048] In addition to the regeneration control of the DPF25a described above, the engine fan 24 is driven in reverse in the following cases:

[0049] Specifically, when starting the engine 16, a low-temperature starting control (engine speed suppression control) is performed to prevent the engine speed from rising above a predetermined level until the engine coolant temperature reaches a specified value (15°C). During this low-temperature starting control, the engine fan 24 is driven in reverse to draw air from inside the aircraft where the engine 16 is located, and the hot air from the engine 16 raises the temperature of the engine coolant in the radiator 23, thereby protecting the engine 16.

[0050] Furthermore, if the engine coolant temperature exceeds the specified value (15°C) and the cold start control is deactivated, the engine fan 24 is switched from reverse drive to forward drive before the engine speed is increased.

[0051] Furthermore, when the wind direction is from the left side of the aircraft, opposite to the side with the radiator cover 23a, the engine fan 24's outside air intake efficiency decreases, causing the engine coolant temperature to rise. By taking advantage of this, when the measured value of the water temperature sensor 26, which measures the engine coolant temperature, rises, it is determined that the wind direction is from the left side of the aircraft. The engine fan 24 is then driven in reverse to draw in air from the inside of the aircraft, passing it through the dustproof net of the radiator cover 23a and expelling it outside the aircraft. This blows away dust and debris such as straw adhering to the radiator cover 23a, preventing clogging and maintaining the cooling function of the radiator 23.

[0052] Furthermore, the blown-away dust is scattered to the right side of the aircraft due to the wind direction from the left, preventing it from falling on the pilot seated in the cockpit and preventing it from accumulating on monitors and other control devices, thus preventing a poor working environment.

[0053] Furthermore, by using the sum of the values ​​measured by the water temperature sensor 26 (which measures the temperature of the engine coolant) and the intake air temperature sensor 27 (which measures the temperature of the intake air) to determine the wind direction, and appropriately controlling the timing and duration of the reverse drive of the engine fan 24 when the wind is coming from the left side of the aircraft, the number of forward and reverse rotation control operations of the fan motor 24a will be reduced, and the control will become more stable. In addition, in the case of a mechanical drive that performs forward and reverse rotation of the engine fan 24 by switching between a forward rotation belt and a reverse rotation belt, reducing the number of forward and reverse rotation switches will improve the durability of the belt, reduce the number of times the transmission shock during switching is felt, and improve passenger comfort.

[0054] Furthermore, if the difference in illuminance measured by the illuminance sensor 28a located on the outside of the radiator cover 23a and the illuminance sensor 28b located on the inside exceeds a predetermined value, it is determined that the radiator cover 23a is about to become clogged. In response, the engine fan 24 is driven in reverse to draw air in from the inside of the aircraft, passing it through the dustproof net of the radiator cover 23a and expelling it outside the aircraft. This blows away dust and debris such as straw adhering to the radiator cover 23a, preventing clogging and maintaining the cooling function of the radiator 23.

[0055] Another DPF25a regeneration control method involves performing DPF25a regeneration when a DPF25a regeneration request is met (when the amount of PM accumulated in the DPF25a, calculated based on the pressure difference detected by the DPF25a's differential pressure sensor, exceeds a predetermined amount). However, if the water temperature sensor 26, which measures the engine coolant temperature, measures a specified value (for example, 60°C) or less, the engine fan 24 is driven in reverse to draw air from inside the engine 16, raising the temperature of the engine coolant in the radiator 23 with the hot air from the engine 16, thereby enabling the DPF25a regeneration function to work properly.

[0056] Furthermore, while the engine fan 24 is in reverse drive mode, if the value measured by the water temperature sensor 26, which measures the temperature of the engine coolant, becomes higher than a specified value (for example, 60°C), if the value measured by the vehicle speed sensor 4a (vehicle speed) becomes higher than the specified vehicle speed (standard speed MAX), if the sub-transmission lever 18a is in the travel position, or if the threshing lever 18b is in the ON position for engaging the harvesting device 15 and the threshing device 6, the engine fan 24 is switched from reverse drive to forward drive to draw in outside air, cool the radiator 23 to lower the temperature of the engine coolant, and blow air towards the engine 16 inside the machine to directly cool the engine 16, DPF 25a and SCR 25b, thereby preventing the engine 16 from overheating and the engine oil temperature from rising. [Explanation of Symbols]

[0057] 6. Working equipment (threshing equipment) 15 Working equipment (reaping equipment) 16 Engine 18a Sub-gear lever 18b Working lever (cutting / removal lever) 19 Control device 24 Engine Fan 25a Exhaust gas purification system (DPF) 26 Water temperature sensor

Claims

1. A work vehicle equipped with an exhaust gas purification device (25a), an engine fan (24) for cooling the engine (16), and a water temperature sensor (26) for detecting the temperature of the engine coolant of the engine (16), wherein the engine fan (24) can rotate in both forward and reverse directions, and a control device (19) drives the engine fan (24) in reverse to raise the temperature of the engine coolant when the temperature of the engine coolant is below a specified value.

2. The work vehicle according to claim 1, characterized in that when the engine coolant temperature rises above a specified value while the engine fan (24) is in reverse rotation, the engine fan (24) is rotated from reverse to forward rotation to draw in outside air and lower the engine coolant temperature.

3. The work vehicle according to claim 1, characterized in that, while the engine fan (24) is in reverse rotation, if the vehicle speed exceeds a specified vehicle speed, if the sub-transmission lever (18a) is in the travel position, or if the work lever (18b) is in the drive-engagement position, the engine fan (24) is switched from reverse to forward rotation to draw in outside air and lower the temperature of the engine coolant.

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