Method and system for generating an alert regarding a hydraulic actuation system

Abstract

A method for providing an alert for a hydraulic actuation system for actuating a hydraulic cylinder is disclosed. The hydraulic control system includes a hydraulic fluid tank and a hydraulic fluid filter. The method includes: monitoring a pressure drop across the hydraulic fluid filter; determining a characteristic change rate regarding a rate of change of the pressure drop over at least one time period during which the hydraulic fluid flows through the hydraulic fluid filter; determining whether the hydraulic fluid is dirty based at least on the characteristic change rate; and generating an alert if it is determined that the hydraulic fluid is dirty.

Description

Technical Field

[0001] The present invention relates to methods and systems for generating warnings in hydraulic actuation systems. In particular, the present invention relates to generating warnings when hydraulic fluid needs to be replaced or when a filter is clogged. Background Art

[0002] A dump truck, sometimes called a dump truck or tipper, is a vehicle typically used in the construction industry to transport material (e.g., gravel or sand). A dump truck typically includes an engine, a cab, and a trailer. The trailer usually has a trailer chassis or frame with a dump truck body, a container in the form of an open top cube, pivotally mounted thereto. A hydraulic cylinder is provided between the frame and the dump truck body and can be extended to pivot the dump truck body to a tilted position, in which the load is emptied from the body. The hydraulic cylinder can be retracted to lower the dump truck body. It will be appreciated that this is only one form of dump truck and that other types exist.

[0003] Dump trucks are usually provided with a hydraulic actuation system for actuating hydraulic cylinders. Typically such hydraulic actuation systems include an oil tank, a pump and a valve assembly. The oil tank is provided with an oil filter for filtering out particulate matter in the oil, and an air filter for filtering out particulate matter in the air sucked into the oil tank. Over time, the air filter may be clogged (or blocked) by particles such as sand, dust, etc. Similarly, the oil filter may be clogged (or blocked) by particles such as sand, dust, or metal particles from other components of the hydraulic circuit (such as a pump or hydraulic cylinder). At the same time, the oil filter is not completely effective, so that over time, the particulate matter in the oil increases and the oil becomes dirty. Certain types of particles in the oil, such as metal particles, can be particularly harmful to the hydraulic actuation system. Moreover, once the filter is clogged, the efficiency of the system will deteriorate.

[0004] It is therefore very important to change filters and oil regularly; however, this may not be possible all the time for different reasons. Summary of the invention

[0005] According to one aspect, a method of generating an alert about a hydraulic actuation system for actuating a hydraulic cylinder is provided, the hydraulic control system including a hydraulic fluid tank and a hydraulic fluid filter, the method comprising: monitoring a pressure drop across the hydraulic fluid filter; determining a characteristic rate of change regarding a rate of change of the pressure drop over at least one time period of hydraulic fluid flowing through the hydraulic fluid filter; determining whether the hydraulic fluid is dirty based at least on the characteristic rate of change; and generating an alert if it is determined that the hydraulic fluid is dirty (or needs to be replaced). The method may allow for automatic determination that the oil must be replaced when contaminated. The contamination may include microscopic matter, such as sand and / or gravel or metal particles. This may prevent damage to the hydraulic cylinder and other components of the hydraulic actuation system.

[0006] The pressure drop may be monitored using at least one upstream pressure sensor measuring the pressure upstream of the hydraulic fluid filter. The pressure drop may be monitored using at least one downstream pressure sensor measuring the pressure downstream of the hydraulic fluid filter. The upstream pressure sensor and the downstream pressure sensor may be located on either side of the hydraulic fluid filter. The or each pressure sensor may be an electronic pressure gauge arranged to generate an electronic pressure signal, the value of which is pressure-dependent. A single pressure sensor suitably calibrated (e.g. with respect to atmospheric pressure or standard pressure) may be used to monitor the pressure drop, or two pressure sensors may be used.

[0007] The method may further comprise generating a pressure drop parameter in relation to the monitored pressure drop, wherein the rate of change of the characteristic is related to the rate of change of the pressure drop parameter.If two pressure sensors are present, the pressure drop parameter may relate to the difference between signals generated by the upstream and downstream pressure sensors.

[0008] The method may also include monitoring the temperature of the hydraulic fluid, wherein the rate of change of the characteristic is determined based on at least the monitored pressure drop and the monitored temperature. The viscosity of the hydraulic fluid is affected by temperature, and the pressure drop is affected by viscosity. Therefore, the hydraulic fluid temperature can be used to normalize or normalize all readings.

[0009] The method may also include monitoring a temperature of the hydraulic fluid; generating a pressure drop parameter related to the monitored pressure drop; normalizing the pressure drop parameter based on the temperature of the hydraulic fluid; and determining a characteristic change rate based on a rate of change of the normalized pressure drop parameter.

[0010] The method may also include determining whether hydraulic fluid is flowing through the hydraulic fluid filter. This may be accomplished by analyzing a pressure signal (e.g., a pressure drop) or using a flow sensor. When it is determined that hydraulic fluid is flowing through the hydraulic fluid filter, the pressure drop may only be used for analysis, monitoring, or recording.

[0011] The rate of change of the characteristic may be determined during a single period of time (i.e., during a single fluid cycle) of hydraulic fluid flowing through the hydraulic fluid sensor. The single period of time may be a continuous operating period of time. The rate of change of the characteristic may be determined during multiple periods of time (i.e., multiple fluid cycles) of hydraulic fluid flowing through the hydraulic fluid filter. The rate of change of the characteristic may include a rate of change of a parameter.

[0012] Determining whether the hydraulic fluid is dirty may include comparing the rate of change of the characteristic to reference data. The comparison may be a direct comparison or an indirect comparison. For example, the characteristic may be converted to another form before the comparison. When the rate of change of the characteristic reaches a threshold, it may be determined that the hydraulic fluid is dirty. Generating an alert may include generating a visual and / or audible alert.

[0013] According to another aspect, a system for generating a warning about a hydraulic actuation system for actuating a hydraulic cylinder is provided, the hydraulic control system including a hydraulic fluid tank and a hydraulic fluid filter, the system including: a pressure drop monitoring module, which is configured to monitor the pressure drop of the hydraulic fluid filter; a change rate determination module, which is configured to determine a characteristic change rate regarding the rate of change of the pressure drop during at least one time period when the hydraulic fluid flows through the hydraulic fluid filter; a hydraulic fluid quality determination module, which is configured to determine whether the hydraulic fluid is dirty based on at least the characteristic change rate; and a warning generator, which is configured to generate a warning if it is determined that the hydraulic fluid is dirty.

[0014] The system may further include an upstream pressure sensor configured to measure an upstream pressure of the hydraulic fluid filter. The system may further include a downstream pressure sensor configured to measure a downstream pressure of the hydraulic fluid filter. The pressure drop monitoring module may be configured to generate a pressure drop parameter regarding the monitored pressure drop. The rate of change determination module may be configured to determine a characteristic rate of change based on a rate of change of the pressure drop parameter.

[0015] The system may further include a temperature monitoring module configured to monitor a temperature of the hydraulic fluid.The rate of change determination module may be configured to determine a rate of change of the characteristic based at least on the monitored pressure drop and the monitored temperature.

[0016] The system may further include: a temperature monitoring module configured to monitor a temperature of the hydraulic fluid; wherein the pressure drop monitoring module is configured to generate a pressure drop parameter regarding the monitored pressure drop and configured to normalize the pressure drop parameter based on the temperature of the hydraulic fluid; and wherein the rate of change determination module is configured to determine the characteristic rate of change based on the rate of change of the normalized pressure drop parameter. The system may further include a temperature sensor configured to measure the temperature of the hydraulic fluid.

[0017] The system also includes a hydraulic fluid flow determination module configured to determine whether hydraulic fluid flows through the hydraulic fluid filter. The pressure drop monitoring module may be configured to analyze the pressure drop only if it is determined that hydraulic fluid flows through the hydraulic fluid filter.

[0018] The rate of change determination module may be configured to determine a rate of change of a characteristic over a single period of time that hydraulic fluid flows through the hydraulic fluid filter. The rate of change determination module may be configured to determine a rate of change of a characteristic over multiple periods of time that hydraulic fluid flows through the hydraulic fluid sensor. The rate of change of a characteristic may include a rate of change of a parameter.

[0019] The system may further include a storage module that stores reference data. The hydraulic fluid quality determination module may be configured to determine whether the hydraulic fluid is dirty by comparing a rate of change of the characteristic with the data stored in the storage module. The hydraulic fluid quality determination module may be configured to determine that the hydraulic fluid is dirty when the rate of change of the characteristic reaches a threshold value.

[0020] The alert generator may include a visual and / or an audible alert generator.

[0021] According to another aspect, a method for generating an alert about a hydraulic actuation system for actuating a hydraulic cylinder is provided, the hydraulic control system including a hydraulic fluid tank and at least one filter, the method including: monitoring a pressure drop across the at least one filter; determining a pressure drop parameter regarding a pressure drop across the at least one filter during fluid flow through the filter; determining whether the at least one filter is clogged based at least on the pressure drop parameter; and generating an alert if it is determined that the at least one filter is clogged.

[0022] The pressure drop may be monitored using at least one upstream pressure sensor measuring the pressure upstream of the filter. The pressure drop may be monitored using at least one downstream pressure sensor measuring the pressure downstream of the filter. The upstream pressure sensor and the downstream pressure sensor may be located on either side of the filter. The pressure drop parameter may relate to the difference between the signals generated by the upstream pressure sensor and the downstream pressure sensor. The or each hydraulic sensor may be an electronic pressure gauge configured to generate an electronic pressure signal whose value is related to the pressure. A single pressure sensor that is appropriately calibrated (e.g. relative to atmospheric pressure or standard pressure) may be used to monitor the pressure drop, or two pressure sensors may be used.

[0023] The method may also include determining whether fluid has passed through at least one filter. This may be accomplished by analyzing a pressure signal (e.g., a pressure drop) or using a flow sensor. When determining that fluid has passed through at least one filter, the pressure drop may only be used for analysis, monitoring, or recording.

[0024] Determining whether at least one filter is clogged may include comparing a pressure drop parameter to reference data. The comparison may be a direct comparison or an indirect comparison. For example, the pressure drop may be converted to another form before the comparison. When the pressure drop parameter reaches a threshold, it may be determined that at least one filter is clogged. Generating an alert may include generating a visual and / or audible alert.

[0025] The pressure drop across the air filter may be monitored and an alert may be generated if it is determined that the air filter is clogged. The pressure drop across the hydraulic fluid filter may be monitored and an alert may be generated if it is determined that the hydraulic fluid filter is clogged.

[0026] The method may also include monitoring the temperature of the hydraulic fluid, wherein a pressure drop parameter is determined based on at least the monitored pressure drop and the monitored temperature. The pressure drop parameter may be a normalized pressure drop parameter based on the hydraulic fluid temperature. Hydraulic fluid viscosity is affected by temperature, and pressure drop is affected by viscosity. Therefore, the hydraulic fluid temperature may be used to normalize or normalize all readings.

[0027] According to another aspect, a system for generating an alert about a hydraulic actuation system for actuating a hydraulic cylinder is provided, the hydraulic control system including a hydraulic fluid tank and at least one filter, the system including: a pressure drop monitoring module configured to monitor the pressure drop of the at least one filter and configured to determine a pressure drop parameter regarding the pressure drop of the at least one filter when fluid flows through the filter; a filter condition determination module configured to determine whether the at least one filter is clogged based at least on the pressure drop parameter; and an alert generator configured to generate an alert if it is determined that the at least one filter is clogged.

[0028] The system may also include an upstream pressure sensor configured to measure the pressure upstream of the filter. The system may also include a downstream pressure sensor configured to measure the pressure downstream of the filter. The pressure drop parameter may relate to the difference between the signals generated by the upstream pressure sensor and the downstream pressure sensor.

[0029] The system also includes a flow determination module configured to determine whether the fluid flows through the at least one filter. The pressure drop monitoring module may be configured to analyze the pressure drop only if it is determined that the fluid flows through the at least one filter.

[0030] The system may further include a storage module storing reference data. The filter condition determination module may be configured to determine whether the at least one filter is clogged by comparing the pressure drop parameter with the reference data stored in the storage module. The filter monitoring module may be configured to determine that the at least one filter is clogged when the pressure drop parameter reaches a threshold value. The alert generator may include a visual and / or an audible alert generator.

[0031] The pressure drop monitoring module may be configured to monitor the pressure drop of the air filter. The alert generator may be configured to generate an alert if the air filter is determined to be clogged. The pressure drop monitoring module may be configured to monitor the pressure drop of the hydraulic fluid filter. The alert generator may be configured to generate an alert if the hydraulic fluid filter is determined to be clogged.

[0032] The system may further comprise: a temperature monitoring module configured to monitor the temperature of the hydraulic fluid. The pressure drop monitoring module may be configured to determine a pressure drop parameter based at least on the monitored pressure drop and the monitored temperature. The pressure drop parameter may be a normalized pressure drop parameter based on the temperature of the hydraulic fluid.

[0033] According to another aspect, a hydraulic actuation system for actuating a hydraulic cylinder is provided, comprising: a hydraulic fluid tank; a hydraulic fluid filter and / or an air filter; and a system according to any claim herein. The hydraulic fluid filter and / or the air filter may be arranged on a tank wall.

[0034] According to another aspect, there is provided a dump truck comprising: a dump truck body which is pivotally movable relative to a frame; a hydraulic cylinder which is arranged between the frame and the dump truck body and is actuatable to pivot the dump truck body; and a hydraulic actuation system according to any claim herein. The dump truck may be a dump vehicle.

[0035] The present invention may include any combination of features and / or limitations mentioned herein, unless combinations of features are mutually exclusive. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Embodiments of the present invention will now be described by way of example, with reference to the accompanying drawings, in which:

[0037] Attached Figure 1 schematically shows a perspective view of a dump truck;

[0038] Attached Figure 2 The attached Figure 1 A side view of a dump truck without a tractor; and

[0039] Attached Figure 3 A hydraulic actuation system provided with a monitoring system is schematically shown. DETAILED DESCRIPTION

[0040] Attached Figure 1 and 2 A dump truck 1, sometimes called a tipper, is shown comprising a tractor 2 and a trailer 4. The trailer 4 has a trailer chassis or frame 6 to which a dump truck body 8 is pivotally mounted. The dump truck body 8 is pivotally mounted to the chassis 6 about a transverse axis 10 located at the rear of the chassis 6. The dump truck body 8 is in the form of a cubic container with an open top. A rear panel (or door) 12 of the dump truck body 8 is hinged at its upper edge and can be locked and unlocked so that it can be opened to allow the contents of the dump truck body 8 to be emptied. A hydraulic cylinder 14 is provided which is pivotally attached at a lower end to the front of the chassis 6 and at an upper end to the front of the dump truck body 8. The hydraulic cylinder 14 can be extended (as attached) Figure 1 ), to pivot the dump truck body 8 about the axis 10 to a fully dumped position in which any load in the dump truck body 8 is emptied to the ground by unlocking the rear panel 12. The hydraulic cylinder 14 can be retracted to pivot the dump truck body 8 back to a rest position in which it rests on the chassis 6.

[0041] The dump truck 1 further comprises a hydraulic actuation system 20 for actuating the hydraulic cylinder 14. The hydraulic actuation system 20 comprises an oil tank (hydraulic fluid tank) 22, a pump 24 and a valve assembly 26, which are connected by a fluid line to form a fluid circuit. The oil tank 22 comprises an outlet 28 towards the bottom of the oil tank, which is connected to the pump inlet through a fluid pipeline. The oil tank 22 also comprises an inlet 30 towards the top of the oil tank, which is connected to the outlet of the valve assembly 26 through a liquid pipeline. The fluid pipeline also connects the pump 24 outlet to the inlet of the valve assembly 26. The oil tank 22 comprises an oil filter (hydraulic fluid filter) 32, which is arranged in the inlet 30 to filter the oil entering the oil tank. The oil tank 22 also comprises an air hole (open to atmospheric pressure), which is provided with an air filter 34 for filtering the air entering the oil tank 22.

[0042] The valve assembly 26 is provided with a port which is hydraulically connected to the hydraulic cylinder 14 via a fluid line 36. A pilot system (not shown) is also provided for switching the valve assembly 26 in a plurality of configurations. The valve assembly 26 can be switched between the plurality of configurations to operate the hydraulic cylinder 14. In the bypass configuration of the valve assembly 26, oil (hydraulic fluid) is circulated through the pump 24, from the oil tank 22, through the valve assembly 26 and back to the oil tank 22 by operation of the pump 24. Likewise, the oil returning to the oil tank 22 flows through the oil filter 32, which filters out particulate matter in the oil. The particulate matter may be sand or dirt, or more damaging, it may be metal particles from the hydraulic cylinder or other metal components. With the valve assembly 26 in the bypass configuration, the oil level in the oil tank remains substantially constant. This means that only a small amount of air, if any, enters or is exhausted through the air holes.

[0043] In order to extend the hydraulic cylinder 14 to pivot the dump truck body 8 to the full dumping position (such as the attached Figure 1 and 2 ), the valve assembly 26 switches to the raising configuration, wherein the pump 24 pumps oil from the oil tank 22 into the hydraulic cylinder 14, thereby extending the hydraulic cylinder. Therefore, when the cylinder 14 is extended, oil no longer returns to the oil tank 22 (that is, no fluid flows through the oil filter 32) because the pump 24 pumps oil into the cylinder 14. This causes the oil level in the oil tank 22 to drop, thereby drawing air into the oil tank 22 through the air hole. The air passes through the air filter 34, which filters out particulate matter in the air.

[0044] When the hydraulic cylinder 14 has been fully extended (either fully extended or extended a desired amount), the valve assembly 26 returns to the bypass configuration in which oil is circulated from the oil tank 22 through the valve assembly 26 and back to the oil tank 22 by operation of the pump 24. Again, the oil entering the oil tank is filtered by the oil filter 32. In the bypass configuration of the valve assembly 26, the fluid line 28 is closed and thus the hydraulic cylinder 14 remains in the extended configuration.

[0045] To lower the hydraulic cylinder 14, the pump 24 is stopped and the valve assembly 26 is switched to the lowering configuration. In this configuration, the fluid line 28 is opened and the hydraulic cylinder 14 contracts based on the weight of the dump truck body 8 by returning the oil to the tank 22 and passing through the filter 32. This causes the oil level in the tank 22 to rise, which causes air to be discharged from the tank 22 through the air filter 34.

[0046] Each time the hydraulic cylinder 14 is extended, air is drawn into the oil tank 22 through the air holes. Although the air filter 34 filters out most of any type of particulate matter in the air, some particulate matter is drawn into the oil tank 22 and into the oil. Most of the particulate matter in the oil is filtered out by the oil filter 32, but some particulate matter remains in the oil. Over time, the oil filter 32 and the air filter 34 become clogged (or plugged) with particulate matter.

[0047] In addition, the amount of particulate matter in the oil increases over time, causing the oil to become dirty. In order to maintain the efficiency and reliability of the hydraulic actuation system 20, the filters 32, 34 must be replaced and the oil must be replaced periodically. As will be described in detail below, the hydraulic actuation system 20 is provided with a monitoring system 40 that monitors the hydraulic actuation system 20 and can generate an alert indicating that the oil filter 32 should be replaced, the air filter 34 should be replaced, or the oil should be replaced.

[0048] Figure 3 A monitoring system 40 is shown for monitoring the hydraulic actuation system 20. The monitoring system 40 includes an upstream oil pressure sensor 42, an oil temperature sensor 44, an upstream air pressure sensor 48, and a downstream air pressure sensor 50. The upstream oil pressure sensor 42 is located upstream of the oil filter 32 and is configured to measure the upstream oil pressure of the oil filter 32. The oil temperature sensor 44 is located in the upstream oil flow of the oil filter 32 and is configured to measure the oil temperature. The output of the upstream pressure sensor 42 can be calibrated so that it can be used to measure or monitor the pressure drop of the oil filter. The upstream air pressure sensor 48 is outside the oil tank 22 and is configured to measure the ambient air pressure. The downstream air pressure sensor 50 is located in the oil tank 22 and is configured to measure the air pressure in the oil tank 22. Thus, the two air pressure sensors 48, 50 can be used to measure the pressure drop of the air filter 34. The pressure sensors 42, 48, 50 are electronic pressure sensors configured to generate an electronic signal representing the measured pressure. The temperature sensor 44 is also configured to generate an electronic signal representing the measured oil temperature.

[0049] The monitoring system 40 also includes a pressure drop monitoring module 52, a rate of change determination module 54, an oil quality determination module 56, an oil filter condition determination module 58, an air filter condition determination module 60, and a display 62. The pressure sensors 42, 48, 50 and the temperature sensor 44 are all connected to the pressure drop monitoring module 52 through appropriate cables so that the module 52 can obtain the electronic signals generated by the sensors. It should be appreciated that in other embodiments, the sensors 42, 44, 48, 50 can be wirelessly connected to the module 52. As described below, the pressure drop monitoring module 52 is configured to perform different functions.

[0050] The pressure drop monitoring module 52 is configured to monitor the signal received from the oil pressure sensor 42 to determine when fluid is flowing through the oil filter 32 (i.e., if a pressure increase is detected, it is determined that oil is flowing through the filter 32). The pressure drop monitoring module 52 is also configured to analyze the pressure drop across the oil filter 32 and determine the oil pressure drop parameter ΔPo by monitoring the signal received from the oil pressure sensor 42 when fluid is flowing through the oil filter 32. Since the viscosity of oil varies with the temperature of the oil, the pressure drop monitoring module 52 is also configured to monitor the signal received from the temperature sensor 44 and correct (or normalize) the oil pressure drop parameter ΔPo based on the temperature (i.e., the corrected pressure drop parameter ΔPo is independent of the oil temperature and thus the viscosity). The pressure drop monitoring module 52 is also configured to monitor the signal received from the air pressure sensors 48, 50 to determine when air is flowing through the air filter 34 (i.e., if a pressure drop increase is detected, it is determined that air is flowing through the air filter 34). The pressure drop monitoring module 52 is further configured to analyze the pressure drop of the air filter 34 and determine the air pressure drop parameter ΔP by monitoring the signal received from the pressure sensor 48 when the fluid flows through the air filter 34. A .

[0051] The rate of change determination module 54 is connected to the pressure drop monitoring module 52 and is configured to calculate the rate of change of the oil pressure drop parameter ΔPo. The rate of change can be calculated over one operating cycle (i.e., over a single continuous period of time), or over multiple operating cycles (e.g., average pressure drop parameters for each operating cycle can be determined and these can be used to generate the rate of change of ΔPo). The oil quality determination module 56 is configured to receive the rate of change of the oil pressure drop parameter ΔPo and is configured to determine whether the oil is dirty (i.e., it contains too much particulate matter) based on the rate of change. This determination is made by comparing the received rate of change with pre-stored data stored in the module 56.

[0052] The oil filter condition determination module 58 is configured to receive the oil pressure drop parameter ΔPo and is configured to determine whether the oil filter 32 is clogged (i.e., blocked / clogged by particulate matter) based on the pressure drop parameter ΔPo. This determination is made by comparing the received pressure drop parameter ΔPo with pre-stored data stored in the module 58. The air filter condition determination module 60 is configured to receive the air pressure drop parameter ΔPo. A and is constructed based on the pressure drop parameter ΔP A Determine if the air filter 34 is clogged (ie, blocked / clogged by particulate matter). By comparing the received pressure drop parameter ΔP A This determination is made based on pre-stored data stored in module 60.

[0053] The display 62 is connected to the oil quality determination module 56, the oil filter condition determination module 58, and the air filter condition determination module 60. The display 62 is configured to generate an alert if the oil quality determination module 56 determines that the oil is dirty, to generate an alert if the oil filter condition determination module 58 determines that the oil filter 32 is blocked, and to generate an alert if the air filter condition determination module 60 detects that the air filter 34 is blocked. In this embodiment, the display 62 is mounted in the dashboard of the tractor 2 so that it is easily visible to the operator. However, in other embodiments, it may be located externally, or it may be in the form of a wireless handheld device (e.g., a smartphone or tablet). If the display 62 is provided by a portable wireless device, such as a smartphone or tablet, it may also include any or all of the modules 52, 54, 56, 58, 60, and may communicate wirelessly with the sensors 42, 44, 48, 50.

[0054] The operation of the hydraulic actuation system 20 will now be described.

[0055] In use, when the valve assembly 26 is in the bypass configuration, oil flows through the oil filter 32, which filters particulate matter from the oil. The upstream oil pressure sensor 42 generates an electronic signal representing the upstream oil pressure of the filter 32 and the signal is received by the pressure drop monitoring module 52. Due to the flow through the oil filter 32, the upstream oil pressure of the oil filter 32 increases, so that the pressure drop monitoring module 52 determines that the oil flows through the oil filter 32. In response to this determination, the electronic pressure signal generated by the pressure sensor 42 is analyzed. The pressure drop monitoring module 52 is calibrated and uses the electronic signal generated by the upstream pressure sensor 42 and the electronic signal generated by the oil temperature sensor 44 to calculate a normalized pressure drop parameter ΔPo regarding the pressure drop of the oil filter. The pressure drop parameter ΔPo is normalized based on the measured temperature so that the pressure drop parameter ΔPo is independent of the temperature and the corresponding oil viscosity. A higher pressure drop corresponds to the oil filter 32 being more blocked / clogged. Therefore, the oil filter condition determination module 58 compares the calculated pressure drop parameter ΔPo with a threshold value of the pressure drop parameter. If the calculated pressure drop parameter ΔPo has reached the threshold value of the pressure drop parameter, it is determined that the oil filter 32 is clogged and should be replaced. In response to this determination, the display 62 generates an alert, such as a visual instruction, to remind the operator that the oil filter 32 should be replaced. Within an operating cycle, the rate of change determination module 54 also uses the calculated oil pressure drop parameter ΔPo to calculate a characteristic change rate (e.g., a rate of change of the parameter) regarding the rate of change of the pressure drop of the oil filter 32. The higher the rate of change of the pressure drop parameter, the more particulate matter there is in the oil (i.e., the filter is clogged faster due to the more particulate matter in the oil). Therefore, the oil quality determination module 56 compares the calculated rate of change with the threshold value of the rate of change. If the calculated rate of change has reached the threshold value, it is determined that the oil is too dirty (i.e., it contains too much particulate matter) and should be replaced. In response to this determination, the display 62 generates an alert, such as a visual instruction, to remind the operator that the oil should be replaced. In various embodiments, the average pressure drop parameter ΔPo is recorded for each operating cycle. The rate of change of a characteristic, such as the rate of change of a parameter, is calculated for a plurality of operating cycles, and this rate of change of the parameter is used to determine whether the oil is too dirty.

[0056] When the valve assembly 26 is in the raised configuration (i.e., when the cylinder 14 is extended), air flows through the air filter 34, which filters particulate matter from the air. The upstream and downstream air pressure sensors 48, 50 generate electronic signals that represent the air pressure upstream and downstream of the filter 34, respectively. These signals are received by the pressure drop monitoring module 52. Due to the flow through the air filter 34, the pressure drop across the air filter 34 increases (i.e., the difference between the values ​​of the two signals increases) and the pressure drop monitoring module 52 thus determines that air is flowing through the air filter 34. In response to this determination, the electronic pressure signals generated by the air pressure sensors 48, 50 are analyzed. The pressure drop monitoring module 52 is calibrated and uses the electronic signals generated by the upstream and downstream pressure sensors 48, 50 to calculate a pressure drop parameter ΔP regarding the pressure drop across the air filter 34. A A higher pressure drop corresponds to a more blocked / clogged air filter 34. Therefore, the air filter condition determination module 60 compares the calculated pressure drop parameter ΔP to A and the threshold of the pressure drop parameter. If the calculated pressure drop parameter ΔP A If the threshold value of the pressure drop parameter has been reached, it is determined that the air filter 34 is clogged and should be replaced. In response to this determination, the display 62 generates an alert, such as a visual instruction, to remind the operator that the air filter 34 should be replaced.

[0057] In the embodiment described above, the presence of fluid flowing through the filters 32, 34 is determined based on the signals generated by the pressure sensors. However, it should be appreciated that in other embodiments, other methods may be used to determine whether fluid is flowing through the filters. For example, operating parameters of the hydraulic actuation system can be used to determine the presence of fluid flow (e.g., by operation of the pump and the valve assembly being in a bypass configuration, it can be assumed that oil is flowing through the oil filter). Alternatively, in other embodiments, oil flow and air flow can be monitored by flow sensors to determine whether fluid is flowing through the filters.

[0058] The use of a single upstream pressure sensor to monitor the pressure drop across the oil filter 32 has been described, where the system is appropriately calibrated. However, it should be appreciated that two pressure sensors can be used, one on each side of the oil filter, to measure the pressure drop. Also, the use of two pressure sensors to monitor the pressure drop across the air filter 34 has been described, one on each side of the air filter 34. However, in other embodiments, a single pressure sensor can be used, such as a single pressure sensor can be located in the oil tank to measure the internal pressure.

[0059] In the embodiment described above, the monitoring system 40 monitors the filter and oil quality at all times. However, in another configuration, a test mode can be entered in which the filter and oil quality are evaluated. For example, using a touch screen display, the operator can enter a test mode in which the system checks whether the oil filter is clogged, whether the air filter is clogged, or whether the oil is dirty. This can be done automatically by flowing oil through the oil filter 32 for a sufficient period of time to analyze the pressure drop and the rate of change of the pressure drop to evaluate the oil quality. The test mode can also flow air through the air filter 34 for a sufficient period of time to analyze the pressure drop.

[0060] In addition to generating alerts indicating the need for remedial action (e.g., filter change, oil change), the monitoring system 40 can predict when the oil needs to be changed, or when the filter needs to be changed. For example, the system can use the rate of change of the pressure drop across the oil filter to predict when the oil filter will become clogged. Also, the system can monitor the rate of change of the pressure drop across the air filter to predict when the air filter will become clogged.

[0061] The monitoring system 40 has been described as having three functions: oil filter check, air filter check, oil quality check. However, it should be appreciated that it may provide only one or any two of these functions.

[0062] Although it has been described that the monitoring system 40 is used to monitor the hydraulic actuation system 20 of the dump truck 1, it can of course be used to monitor the hydraulic actuation system 20 that actuates hydraulic cylinders of other machines.

[0063] The monitoring system 40 may be one of many intelligent systems with which the dump truck 1 is provided, and may therefore be combined with any suitable system for providing information about the dump vehicle and / or the load carried by the dump truck body 8. If multiple intelligent systems are provided, they may share the same, for example, display or processor.

[0064] Some aspects of the apparatus, systems and methods described above may be represented as machine-readable instructions, such as processor control code, for example on a non-volatile carrier medium, such as a hard disk, CD- or DVD-ROM, a programmed memory, such as a read-only memory (firmware), or on a data carrier, such as an optical or electrical signal carrier. For some applications, embodiments of the present invention will be implemented on a DSP (digital signal processor), an ASIC (application-specific integrated circuit), or an FPGA (field programmable gate array). Thus, the code may include conventional program code or microcode, or, for example, code for establishing or controlling an ASIC or FPGA. The code may also include code for dynamically constructing a reconfigurable device, such as a reprogrammable logic gate array. Similarly, the code may include code for a hardware description language, such as Verilog TM or VHDL (very high speed integrated circuit hardware description language). The code may be distributed between multiple connected components that communicate with each other. Where appropriate, the embodiments may also be implemented using code running on a field-(re)programmable analog array or similar device to construct analog hardware.

Claims

1. A method for generating a warning about a hydraulic actuation system for actuating a hydraulic cylinder, the hydraulic actuation system comprising a hydraulic fluid tank and a hydraulic fluid filter, the method comprising: Monitors pressure drop across hydraulic fluid filters; determining a characteristic rate of change regarding a rate of change of an average pressure drop over each operating cycle of hydraulic fluid flowing through the hydraulic fluid filter; determining whether the hydraulic fluid is dirty based on at least the rate of change of the characteristic; and An alarm is generated if the hydraulic fluid is determined to be dirty. 2 . The method of claim 1 , wherein the pressure drop is monitored using at least one upstream pressure sensor that measures the pressure upstream of the hydraulic fluid filter.

3. The method of claim 2, wherein the pressure drop is monitored using at least one downstream pressure sensor that measures pressure downstream of a hydraulic fluid filter.

4. The method of claim 3, wherein the upstream pressure sensor and the downstream pressure sensor are located on an upstream side and a downstream side of the hydraulic fluid filter, respectively.

5. The method of any one of claims 1-4, further comprising generating a pressure drop parameter regarding the monitored pressure drop, wherein the rate of change of the characteristic is related to the rate of change of the pressure drop parameter.

6. The method of any one of claims 1-4, further comprising monitoring a temperature of the hydraulic fluid, wherein the rate of change of the characteristic is determined based on at least the monitored pressure drop and the monitored temperature.

7. The method according to any one of claims 1 to 4, further comprising: Monitor the temperature of hydraulic fluid; generating a pressure drop parameter related to the monitored pressure drop; Normalizing the pressure drop parameter based on the temperature of the hydraulic fluid; and The characteristic change rate is determined based on the rate of change of the normalized voltage drop parameter.

8. The method of any one of claims 1-4, further comprising determining whether hydraulic fluid is flowing through a hydraulic fluid filter.

9. The method of claim 8, wherein the pressure drop is analyzed only when it is determined that hydraulic fluid is flowing through the hydraulic fluid filter.

10. The method of any one of claims 1-4, wherein the rate of change of the characteristic is determined during a single period of time during which hydraulic fluid flows through the hydraulic fluid filter.

11. The method of any one of claims 1-4, wherein the rate of change of the characteristic is determined over a plurality of time periods during which hydraulic fluid flows through the hydraulic fluid filter.

12. The method of any one of claims 1-4, wherein the rate of change of the characteristic comprises a rate of change of a parameter.

13. The method of any one of claims 1-4, wherein determining whether the hydraulic fluid is dirty comprises comparing a rate of change of a characteristic to reference data.

14. The method of claim 13, wherein the hydraulic fluid is determined to be dirty when the rate of change of the characteristic reaches a threshold value.

15. The method of any one of claims 1-4, wherein generating an alert comprises generating a visual and / or audible alert.

16. A system for generating a warning about a hydraulic actuation system for actuating a hydraulic cylinder, the hydraulic actuation system including a hydraulic fluid tank and a hydraulic fluid filter, the system comprising: a pressure drop monitoring module configured to monitor a pressure drop across a hydraulic fluid filter; a rate of change determination module configured to determine a characteristic rate of change regarding a rate of change of an average pressure drop over each operating cycle of hydraulic fluid flowing through a hydraulic fluid filter; a hydraulic fluid quality determination module configured to determine whether the hydraulic fluid is dirty based on at least a rate of change of a characteristic; and A warning generator is configured to generate a warning if it is determined that the hydraulic fluid is dirty.

17. The system of claim 16, further comprising an upstream pressure sensor configured to measure a pressure upstream of the hydraulic fluid filter.

18. The system of claim 17, further comprising a downstream pressure sensor configured to measure a pressure downstream of the hydraulic fluid filter.

19. The system of any one of claims 16-18, wherein the pressure drop monitoring module is configured to generate a pressure drop parameter regarding the monitored pressure drop; and wherein the rate of change determination module is configured to determine the characteristic rate of change based on the rate of change of the pressure drop parameter.

20. The system of any one of claims 16-18, further comprising a temperature monitoring module configured to monitor a temperature of the hydraulic fluid; and wherein the rate of change determination module is configured to determine the rate of change of the characteristic based at least on the monitored pressure drop and the monitored temperature.

21. The system of any one of claims 16-18, further comprising: a temperature monitoring module configured to monitor the temperature of the hydraulic fluid; wherein the pressure drop monitoring module is configured to generate a pressure drop parameter related to the monitored pressure drop and is configured to normalize the pressure drop parameter based on the hydraulic fluid temperature; and The change rate determination module is configured to determine the characteristic change rate based on the change rate of the normalized pressure drop parameter.

22. The system of claim 20, further comprising a temperature sensor configured to measure a temperature of the hydraulic fluid.

23. The system of any one of claims 16-18, further comprising a hydraulic fluid flow determination module configured to determine whether hydraulic fluid flows through the hydraulic fluid filter.

24. The system of claim 23, wherein the pressure drop monitoring module is configured to analyze the pressure drop only when it is determined that hydraulic fluid is flowing through the hydraulic fluid filter.

25. The system of any one of claims 16-18, wherein the rate of change determination module is configured to determine the rate of change of the characteristic over a single period of time during which hydraulic fluid flows through the hydraulic fluid filter.

26. The system of any one of claims 16-18, wherein the rate of change determination module is configured to determine a rate of change of a characteristic over a plurality of time periods of hydraulic fluid flowing through the hydraulic fluid filter.

27. The system of any one of claims 16-18, wherein the rate of change of the characteristic comprises a rate of change of a parameter.

28. The system of any one of claims 16-18, further comprising a storage module storing reference data, wherein the hydraulic fluid quality determination module is configured to determine whether the hydraulic fluid is dirty by comparing a rate of change of the characteristic with the data stored in the storage module.

29. The system of claim 28, wherein the hydraulic fluid quality determination module is configured to determine that the hydraulic fluid is dirty when a rate of change of a characteristic reaches a threshold value.

30. The system of any one of claims 16-18, wherein the alert generator comprises a visual and / or audible alert generator.

31. A hydraulic actuation system for actuating a hydraulic cylinder, comprising: Hydraulic fluid tank; Hydraulic fluid filters; and A system according to any of claims 16-30.

32. The hydraulic actuation system of claim 31, wherein the hydraulic fluid filter is disposed on a tank wall.

33. A method of generating an alert regarding a hydraulic actuation system for actuating a hydraulic cylinder, the hydraulic actuation system comprising a hydraulic fluid tank and at least one filter, the method comprising: monitoring a pressure drop across the at least one filter; determining a pressure drop parameter relating to an average pressure drop across at least one filter during each operating cycle of fluid flowing through the filter; determining whether the at least one filter is clogged based at least on a pressure drop parameter; as well as If it is determined that the at least one filter is clogged, an alert is generated.

34. The method of claim 33, wherein the pressure drop is monitored using at least one upstream pressure sensor that measures the pressure upstream of the filter.

35. The method of claim 34, wherein the pressure drop is monitored using at least one downstream pressure sensor that measures the pressure downstream of the filter.

36. The method of claim 35, wherein the upstream pressure sensor and the downstream pressure sensor are located on opposite sides of the filter.

37. A method as claimed in claim 35 or 36, wherein the pressure drop parameter relates to the difference between the signals produced by the upstream pressure sensor and the downstream pressure sensor.

38. The method of any one of claims 33-36, further comprising determining whether fluid has passed through at least one filter.

39. The method of claim 38, wherein the pressure drop is analyzed only when fluid flow through the at least one filter is determined.

40. The method of any of claims 33-36, wherein determining whether at least one filter is clogged comprises comparing a pressure drop parameter to reference data.

41. The method of claim 40, wherein at least one filter is determined to be clogged when a pressure drop parameter reaches a threshold value.

42. The method of any one of claims 33-36, wherein generating an alert comprises generating a visual and / or audible alert.

43. The method of any one of claims 33-36, wherein the pressure drop is monitored across an air filter and an alert is generated if it is determined that the air filter is clogged.

44. The method of any one of claims 33-36, wherein the pressure drop is monitored across a hydraulic fluid filter and an alert is generated if it is determined that the hydraulic fluid filter is clogged.

45. The method of claim 44, further comprising monitoring a temperature of the hydraulic fluid, wherein the pressure drop parameter is determined based at least on the monitored pressure drop and the monitored temperature.

46. ​​The method of claim 45, wherein the pressure drop parameter is a normalized pressure drop parameter based on hydraulic fluid temperature.

47. A system for generating a warning about a hydraulic actuation system for actuating a hydraulic cylinder, the hydraulic actuation system comprising a hydraulic fluid tank and at least one filter, the system for generating a warning about a hydraulic actuation system for actuating a hydraulic cylinder comprising: a pressure drop monitoring module configured to monitor the pressure drop of the at least one filter and configured to determine a pressure drop parameter regarding an average pressure drop across the filter over each operating cycle of fluid flowing through the at least one filter; a filter condition determination module configured to determine whether the at least one filter is clogged based at least on a pressure drop parameter; and An alert generator is configured to generate an alert if it is determined that the at least one filter is clogged.

48. The system of claim 47, further comprising an upstream pressure sensor configured to measure pressure upstream of the filter.

49. The system of claim 48, further comprising a downstream pressure sensor configured to measure a pressure downstream of the filter.

50. The system of claim 49, wherein the pressure drop parameter relates to a difference between signals generated by an upstream pressure sensor and a downstream pressure sensor.

51. The system of any of claims 47-50, further comprising a flow determination module configured to determine whether fluid flows through at least one filter.

52. The system of claim 51, wherein the pressure drop monitoring module is configured to analyze the pressure drop only when fluid flow through the at least one filter is determined.

53. The system of any one of claims 47-50, further comprising a storage module storing reference data, wherein the filter condition determination module is configured to determine whether the at least one filter is clogged by comparing a pressure drop parameter with the reference data stored in the storage module.

54. The system of claim 53, wherein the filter monitoring module is configured to determine that at least one filter is plugged when a pressure drop parameter reaches a threshold value.

55. The system of any one of claims 47-50, wherein the alert generator comprises a visual and / or audible alert generator.

56. The system of any one of claims 47-50, wherein the pressure drop monitoring module is configured to monitor the pressure drop of the air filter, and wherein the alert generator is configured to generate an alert if it is determined that the air filter is clogged.

57. The system of any one of claims 47-50, wherein the pressure drop monitoring module is configured to monitor a pressure drop across a hydraulic fluid filter, and wherein the alert generator is configured to generate an alert if it is determined that the hydraulic fluid filter is clogged.

58. The system of claim 57, further comprising a temperature monitoring module configured to monitor a temperature of the hydraulic fluid, the pressure drop monitoring module configured to determine a pressure drop parameter based at least on the monitored pressure drop and the monitored temperature.

59. The system of claim 58, wherein the pressure drop parameter is a normalized pressure drop parameter based on hydraulic fluid temperature.

60. A hydraulic actuation system for actuating a hydraulic cylinder, comprising: Hydraulic fluid tank; hydraulic fluid filter and / or air filter; and A system according to any of claims 47-59.

61. The hydraulic actuation system of claim 60, wherein the hydraulic fluid filter and / or the air filter are disposed on a tank wall.

62. A dump truck, comprising: A dump truck body, which is pivotally movable relative to the frame; a hydraulic cylinder disposed between the frame and the dump truck body and actuatable to pivot the dump truck body; as well as A hydraulic actuation system according to claim 31 or 32 or 60 or 61 for actuating a hydraulic cylinder.

63. A dump truck vehicle as claimed in claim 62.

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