Method and system for diagnosing transmission warm-up valve

Abstract

The present disclosure provides methods and systems for diagnosing a transmission warm-up valve. Systems and methods for diagnosing operation of a transmission warm-up valve are presented. In one example, a transmission warm-up valve is commanded to an open position, and an estimated transmission fluid temperature is compared to an actual transmission fluid temperature to determine whether the transmission warm-up valve operates as commanded.

Description

Technical Field

[0001] The present description relates to a method and system for warming an automatic transmission of a vehicle. The method may be particularly useful for an automatic transmission coupled to an engine. Background Art

[0002] At lower temperatures, the viscosity of the fluids in the engine and transmission may be greater than when the engine and transmission are warm. The higher viscosity may cause the engine to operate at a higher load and lower efficiency. Therefore, it may be desirable to warm the engine oil and transmission fluid so that the engine can operate more efficiently as soon as possible after starting. However, if the temperature of the transmission fluid does not increase as quickly as expected, engine emissions may increase and engine efficiency may decrease. Therefore, it may be desirable to provide a way to determine whether subsystem components related to the warming of the transmission fluid are operating normally. Summary of the invention

[0003] The inventors herein have recognized that it may be desirable to diagnose the operation of a device that controls the temperature of a transmission fluid and have developed a method for diagnosing the operation of a transmission warm-up valve, the method comprising: estimating, via a controller, a temperature of the transmission fluid leaving a heat exchanger; and adjusting, via the controller, the operation of the device in response to a difference between the temperature and an actual temperature of the transmission fluid leaving the heat exchanger.

[0004] The operation of the automatic transmission warm-up valve may be diagnosed by estimating the temperature of the transmission fluid exiting the heat exchanger and adjusting the device in response to a difference between the temperature and the actual temperature of the transmission fluid exiting the heat exchanger. For example, if the estimated temperature is greater than the actual temperature by more than a predetermined amount, the display may be adjusted to indicate degradation of the automatic transmission warm-up valve. Additionally, the operation of the engine and / or transmission may be adjusted in response to an indication of degradation of the automatic transmission warm-up valve.

[0005] The present description may provide several advantages. Specifically, the method may provide an indication of valve degradation, which may indicate an increase in vehicle emissions. Additionally, if valve degradation is indicated, the method may provide compensation for engine and / or transmission operation. Furthermore, the method may provide an indication of valve operation without having to directly monitor the valve via a dedicated sensor, thereby reducing system financial expenses.

[0006] When understood individually or in conjunction with the accompanying drawings, the above advantages and other advantages and features of the present specification will be readily apparent from the following detailed description. The term "driver" may be referenced throughout the specification, and the term refers to a human driver or human vehicle operator who is an authorized operator of a vehicle, unless otherwise specified.

[0007] It will be appreciated that the above summary is provided to introduce in simplified form a series of concepts further described in the detailed description. This is not meant to identify the key features of the claimed subject matter, the scope of which is uniquely defined by the claims attached to the detailed description. Furthermore, the claimed subject matter is not limited to implementations that address any disadvantages mentioned above or in any part of this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Advantages described herein will be more fully understood by reading examples of embodiments referred to herein as detailed descriptions when read alone or with reference to the accompanying drawings, in which:

[0009] Figure 1 It is a schematic diagram of the engine;

[0010] Figure 2 An exemplary vehicle powertrain is shown;

[0011] Figure 3 An exemplary heat transfer system for a vehicle is shown;

[0012] Figures 4 to 9 A block diagram showing a method for diagnosing operation of an automatic transmission warm-up valve; and

[0013] Figure 1 0 shows the Figures 4 to 9 An exemplary vehicle operation sequence for the method of FIG. DETAILED DESCRIPTION

[0014] This specification relates to diagnosing the operation of an automatic transmission warm-up valve. The automatic transmission warm-up valve can control the flow of warm engine coolant into a heat exchanger, which can transfer heat from the warm engine coolant to the transmission fluid, thereby heating the transmission fluid. The automatic transmission warm-up valve can be opened shortly after a cold engine start to warm the transmission fluid. The automatic transmission warm-up valve can be supplied with heat from Figure 1 The engine coolant is an engine coolant for an engine of the type shown. The engine may be such as Figure 2 The vehicle may have a powertrain or a portion of a transmission as shown. Figure 3 The vehicle and heat transfer system can be based on Figures 4 to 9 The method shown in the block diagram is used to operate. Fig.10 As shown, the vehicle can Figures 4 to 9 Method operation.

[0015] refer to Figure 1 , the engine 10 is an internal combustion engine including a plurality of cylinders, Figure 1One of the cylinders 33 is shown in FIG. 1 . The engine 10 is controlled by an electronic engine controller 12. The controller is Figure 1 The various sensors receive signals and based on the received signals and instructions stored in the memory of the controller 12, use Figure 1 Various actuators may be used to adjust engine operation. For example, fuel injection timing, spark timing, and poppet valve operation may be adjusted in response to engine position as determined from the output of an engine position sensor.

[0016] Engine 10 includes combustion chamber 30, cylinder 33, and cylinder wall 32, with piston 36 positioned in the cylinder wall and connected to crankshaft 40. Flywheel 97 and ring gear 99 are coupled to crankshaft 40. Starter 96 includes pinion shaft 98 and pinion 95. Pinion shaft 98 can selectively advance pinion 95 to engage ring gear 99. Starter 96 can be mounted directly to the front of the engine or the rear of the engine. In some examples, starter 96 can selectively supply torque to crankshaft 40 via, for example, a chain. In one example, starter 96 is in a basic state when not engaged to the engine crankshaft. Combustion chamber 30 is shown as being in communication with intake manifold 44 and exhaust manifold 48 via respective intake valve 52 and exhaust valve 54. Each intake valve and exhaust valve can be operated by intake cam 51 and exhaust cam 53. The position of intake cam 51 can be determined by intake cam sensor 55. The position of exhaust cam 53 can be determined by exhaust cam sensor 57. Intake cam 51 and exhaust cam 53 are movable relative to crankshaft 40 .

[0017] Fuel injector 66 is shown positioned to inject fuel directly into cylinder 33, which is referred to as direct injection by those skilled in the art. Alternatively, fuel can be injected into the intake port, which is referred to as port injection by those skilled in the art. Fuel injector 66 delivers liquid fuel in proportion to the pulse width of the signal from controller 12. Fuel is delivered to fuel injector 66 by a fuel system (not shown), which includes a fuel tank, a fuel pump, and a fuel rail (not shown). In addition, intake manifold 44 is shown to be connected to an optional electronic throttle 62, which adjusts the position of throttle plate 64 to control the air flow from intake port 42 to intake manifold 44. In one example, a low-pressure direct injection system can be used, in which the fuel pressure can be increased to about 20-30 bar. Alternatively, a high-pressure dual-stage fuel system can be used to generate higher fuel pressures. In some examples, throttle 62 and throttle plate 64 can be positioned between intake valve 52 and intake manifold 44, so that throttle 62 is an intake port throttle.

[0018] Distributorless ignition system 88 provides an ignition spark to combustion chamber 30 via spark plug 92 in response to controller 12. Universal Exhaust Gas Oxygen (UEGO) sensor 126 is shown coupled to exhaust manifold 48 upstream of catalytic converter 70. Alternatively, a two-state exhaust gas oxygen sensor may be substituted for UEGO sensor 126.

[0019] In one example, converter 70 may include multiple catalyst bricks. In another example, multiple emission control devices, each having multiple bricks, may be used. In one example, converter 70 may be a three-way type catalyst.

[0020] The controller 12 Figure 1 1 is shown as a conventional microcomputer including: a microprocessor unit 102, input / output ports 104, read-only memory 106 (e.g., non-transitory memory), random access memory 108, keep alive memory 110, and a conventional data bus. Controller 12 is shown as receiving various signals from sensors coupled to engine 10 in addition to those signals previously discussed, including: engine coolant temperature (ECT) from temperature sensor 112 coupled to cooling sleeve 114; position sensor 134 coupled to driver demand pedal 130 for sensing force applied by human driver 132; measurement of engine manifold absolute pressure (MAP) from pressure sensor 122 coupled to intake manifold 44; engine position sensor from engine position sensor 118 sensing position of crankshaft 40; measurement of air mass entering the engine from sensor 120; pedal position from pedal position sensor 154 when human driver 132 applies pedal 150 to decelerate the vehicle; and measurement of throttle position from sensor 58. Barometric pressure may also be sensed (sensor not shown) for processing by controller 12. In a preferred aspect of the present description, engine position sensor 118 produces a predetermined number of equally spaced pulses every revolution of the crankshaft from which engine speed (RPM) can be determined.

[0021] The controller 12 may receive input from a human / machine interface 170. In one example, the human / machine interface 170 may be a touch screen display. In other examples, the human / machine interface 170 may be a keyboard, buttons, or other known interfaces. The controller 12 may also display information and data to the human / machine interface 170.

[0022] In some examples, the engine can be coupled to an electric motor / battery system in a hybrid vehicle. Additionally, in some examples, other engine configurations can be employed, such as a diesel engine.

[0023] During operation, each cylinder within engine 10 typically undergoes a four-stroke cycle: the cycle includes an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke. During the intake stroke, generally, exhaust valve 54 is closed and intake valve 52 is opened. Air is introduced into combustion chamber 30 via intake manifold 44, and piston 36 moves to the bottom of the cylinder to increase the volume within combustion chamber 30. The position of piston 36 near the bottom of the cylinder and at the end of its stroke (e.g., when combustion chamber 30 is at its largest volume) is typically referred to by those of skill in the art as bottom dead center (BDC). During the compression stroke, intake valve 52 and exhaust valve 54 are closed. Piston 36 moves toward the cylinder head to compress the air within combustion chamber 30. The point at which piston 36 is at the end of its stroke and closest to the cylinder head (e.g., when combustion chamber 30 is at its smallest volume) is typically referred to by those of skill in the art as top dead center (TDC). In a process hereinafter referred to as injection, fuel is introduced into the combustion chamber. In a process hereinafter referred to as ignition, the injected fuel is ignited by known ignition means, such as spark plug 92, resulting in combustion. During the expansion stroke, the expanding gases push piston 36 back to BDC. Crankshaft 40 converts piston movement into rotational torque of the rotating shaft. Finally, during the exhaust stroke, exhaust valve 54 opens to release the combusted air-fuel mixture to exhaust manifold 48, and the piston returns to TDC. It should be noted that the above is shown only as an example, and the intake and exhaust valve opening and / or closing timings may be varied, such as to provide positive or negative valve overlap, late intake valve closing, or various other examples.

[0024] Reference now Figure 2 , the figure is a block diagram 200 of a vehicle 290 including a powertrain or driveline 200 . Figure 2 The powertrain system includes Figure 1 1. Engine 10 is shown. It may be noted that this example shows a single controller. However, in other examples, the functions and operations performed by controller 12 may be distributed among multiple controllers.

[0025] The engine crankshaft 40 can be coupled to the torque converter 206, and the torque converter 206 is mechanically coupled to the automatic transmission 208 via the transmission input shaft 207. The torque converter 206 can also include a torque converter clutch 209. The automatic transmission 208 includes a gear clutch (e.g., gear 1-10) 210 and a forward clutch 212. The automatic transmission 208 is a fixed step ratio transmission. The gear clutch 210 and the forward clutch 212 can be selectively engaged to change the ratio of the actual total number of revolutions of the input shaft 207 to the actual total number of revolutions of the wheels 218. The gear clutch 210 can be engaged or disengaged by adjusting the fluid supplied to the clutch via a shift control solenoid valve (not shown). The torque output from the automatic transmission 208 can also be transmitted to the wheels 218 via the output shaft 215 to propel the vehicle. Specifically, the automatic transmission 208 can transmit the input drive torque at the input shaft 207 in response to the vehicle driving conditions before transmitting the output drive torque to the wheels 218. The controller 12 can selectively activate the torque converter clutch 209, the range clutch 210, and the forward clutch 212. The controller 12 can also selectively deactivate or disengage the torque converter clutch 209, the range clutch 210, and the forward clutch 212.

[0026] In response to a request to increase the speed of the vehicle 290, the controller 12 may obtain a driver demand torque or power request from a driver demand pedal or other device. The controller 12 commands the engine 10 to provide the requested torque via one or more torque actuators 204. In response to a shift schedule and a torque converter clutch locking schedule that may be based on the transmission input shaft torque and vehicle speed, the torque converter clutch 209 may be locked and a gear may be engaged via the gear clutch 210.

[0027] The engine torque may be controlled by the controller 12 by adjusting a combination of spark timing, fuel pulse width, fuel pulse timing, and / or air charge by controlling the throttle opening and / or valve timing, valve lift, and boost pressure of a turbo or supercharged engine. In the case of a diesel engine, the controller 12 may control the engine torque output by controlling a combination of fuel pulse width, fuel pulse timing, and air charge. In all cases, engine control may be performed on a cylinder-by-cylinder basis to control the engine torque output.

[0028] The controller 12 may receive the transmission input shaft position via a position sensor (not shown) and convert the transmission input shaft position into an input shaft speed by differentiating the signal from the position sensor. The controller 12 may receive the transmission output shaft torque from a torque sensor (not shown). The controller 12 may also receive additional transmission information from sensors 277, which may include, but are not limited to, a pump output line pressure sensor, a transmission hydraulic pressure sensor (e.g., a gear clutch fluid pressure sensor), a driver presence detection switch, a driver door switch, a heartbeat sensor, and an ambient temperature sensor.

[0029] In some examples, the controller 12 can communicate with the navigation system 235 (e.g., a second controller) and exchange data. The navigation system 235 can determine the location and speed of the vehicle 290 via data received from a global positioning satellite (not shown). The navigation system 235 can also receive input via voice commands or via a human / machine interface to determine the vehicle destination. The navigation system 235 can select a driving route based on the current location of the vehicle and the destination of the vehicle. The navigation system 235 can determine the driving route based on a map that can be stored in the navigation system 235. The map stored in the navigation system 235 can include the location of traffic signs, gas stations, and other points of interest. In addition, the navigation system 235 can predict when the vehicle speed is expected to increase based on the current location of the vehicle and mapping data (e.g., road slope, driving route height, stored traffic signals or sign locations, etc.). The navigation system 235 can notify the controller 12 of the upcoming or predicted time and / or driving route location at which the vehicle speed is predicted to increase.

[0030] The controller 12 can communicate with the satellite 275 via the transceiver 220. Alternatively, the transceiver 220 can be a transmitter-receiver. The controller 12 can receive input (e.g., data including the location and / or time at which the vehicle speed increases and / or decreases) from the satellite 275 via the transceiver 220 or broadcast vehicle data to the satellite. The controller 12 can also communicate with the network 270 (e.g., cellular, vehicle-to-vehicle, vehicle-to-infrastructure network) via the transceiver 225. Alternatively, the transceiver 225 can be a transmitter-receiver. The controller 12 can broadcast vehicle data to the network 270 via the transceiver 225 and receive input from the network. The network 270 and / or the satellite 275 can communicate with a cloud computer 289 (e.g., a remote server). The cloud computer (e.g., a second controller) can communicate the time and / or location of the expected vehicle speed increase or decrease to controller 12 via satellite 275 and network 270 via radio or microwave frequency 288 based on the vehicle's current position, road grade, traffic information (e.g., traffic jams, accident locations, etc.), and previous human driver behavior.

[0031] therefore, Figure 1 and Figure 2 A system for operating a vehicle is provided, the system comprising: a vehicle, the vehicle comprising an internal combustion engine and a pedal; and a controller, the controller comprising executable instructions stored in a non-transitory memory, the executable instructions causing the controller to inhibit an automatic stop of the internal combustion engine in response to a predicted condition indicating that the operator has changed his mind during a look-ahead window. In a first example, the system further comprises additional instructions for performing the following operations: not inhibiting the automatic stop of the internal combustion engine in response to a predicted condition indicating that the operator has changed his mind during the look-ahead window. In a second example that may include the first example, the system comprises: wherein the look-ahead window is a future time period, and wherein the look-ahead window starts at a current time, or wherein the look-ahead window starts at a time or vehicle position when a driver input for decelerating the vehicle is applied. In a third example that may include one or more of the first and second examples, the system comprises: wherein the look-ahead window is a distance in a travel path of the vehicle, and further comprises: adjusting the distance in response to one or more of a rate at which the vehicle speed decreases, a location of a traffic sign or signal, or a location where the road profile and / or attributes change. In a fourth example, which may include one or more of the first to third examples, the system further includes additional instructions for performing the following operations: predicting a condition indicating that the operator has changed his mind during the look-ahead window. In a fifth example, which may include one or more of the first to fourth examples, the system includes: wherein the predicted condition includes an increase in vehicle speed. In a sixth example, which may include one or more of the first to fifth examples, the system further includes additional instructions for performing the following operations: receiving a predicted condition indicating that the operator has changed his mind during the look-ahead window from a second controller.

[0032] Reference now Figure 3 , a heat transfer system 300 is shown. In this example, the heat transfer system 300 includes an engine coolant circuit 302 and a transmission fluid circuit 350. The engine coolant circuit 302 includes the engine 10, a radiator 320, a thermostat 322, an engine coolant pump 315, an automatic transmission warm-up valve 306, and a heat exchanger 304. The transmission fluid circuit 350 includes the transmission 208, a transmission fluid pump 330, a torque converter 206, a heat exchanger 304, and an oil pan 332. The flow direction through the engine coolant circuit 302 and the transmission fluid circuit 350 is indicated by arrows.

[0033] The heat transfer system includes a coolant heat exchanger inlet temperature sensor 310, a coolant heat exchanger outlet sensor 308, a transmission fluid heat exchanger inlet temperature sensor 314, and a transmission fluid heat exchanger outlet temperature sensor 312 for sensing coolant and transmission fluid temperatures at the heat exchanger 304. The coolant heat exchanger inlet temperature sensor 310 senses the temperature of the coolant entering the heat exchanger 304. The coolant heat exchanger outlet temperature sensor 308 senses the temperature of the coolant leaving the heat exchanger 304. The transmission fluid heat exchanger inlet temperature sensor 314 senses the temperature of the transmission fluid entering the heat exchanger 304. The transmission fluid heat exchanger outlet temperature sensor 312 senses the temperature of the transmission fluid leaving the heat exchanger 304.

[0034] The heat transfer system 300 may supply warm engine coolant to the heat exchanger 304 via opening the automatic transmission warm-up valve 306. The warm coolant may transfer thermal energy to the transmission fluid circulating through the heat exchanger 304. The controller 12 may open and close the automatic transmission warm-up valve 306 in response to temperature sensed via the temperature sensors 308-314 and other vehicle operating conditions.

[0035] Figures 1 to 3A system provides a transmission warming system, the transmission warming system comprising: an internal combustion engine; an automatic transmission; a heat exchanger; an automatic transmission warm-up valve; and a controller, the controller comprising executable instructions stored in a non-transitory memory, the executable instructions causing the controller to generate an estimate of the temperature of the transmission fluid leaving the heat exchanger and a comparison of the actual temperature of the transmission fluid leaving the heat exchanger, and adjust the operation of the automatic transmission or the internal combustion engine in response to the comparison. In a first example, the system comprises: wherein the estimate of the temperature of the transmission fluid is based on a state of a command of the automatic transmission warm-up valve. In a second example that may include the first example, the system comprises: wherein the estimate of the temperature of the transmission fluid is also based on a specific heat acceptance value of the heat exchanger. In a third example that may include one or both of the first and second examples, the system comprises: wherein the estimate of the temperature of the transmission fluid is further based on an engine coolant temperature. In a fourth example that may include one or more of the first to third examples, the system comprises: wherein the estimate of the temperature of the transmission fluid is further based on an engine speed. In a fifth example, which may include one or more of the first to fourth examples, the system includes: wherein adjusting the operation of the transmission includes modifying a transmission shift schedule. In a sixth example, which may include one or more of the first to fifth examples, the system includes: wherein adjusting the operation of the engine includes adjusting engine valve timing.

[0036] Reference now Figures 4 to 9 , a block diagram for estimating transmission fluid temperature and diagnosing the operation of an automatic transmission warm-up valve is shown. Figures 4 to 9 The methods described in the block diagrams may be incorporated into one or more controllers (e.g., Figure 1 12). The executable instructions can be Figures 1 to 3 A system of systems collaborates to retrieve information or data from sensors and adjust the position of actuators in the real world. Figures 4 to 9 The arrows in the diagram indicate the direction of data flow in the diagram.

[0037] Diagram 400 illustrates signals and blocks that operate to provide an indication of automatic transmission warm-up (ATWU) valve degradation or absence based on estimated transmission fluid temperature and actual valve transmission fluid temperature.

[0038] At box 402, engine speed (RPM) and transmission fluid flow rate are received as inputs to box 402. The inputs are applied to a reference table or function, such as Figure 5 Block 402 outputs Figure 3 The transmission fluid specific heat receiving value of the heat exchanger 304 is input to block 404 .

[0039] At block 404, the engine coolant temperature, the transmission output temperature (eg, Figure 3 The transmission fluid temperature at the temperature sensor 314) and the transmission fluid specific heat receiving value of the heat exchanger 304 are used as inputs to the block 404. The inputs are applied to a reference table or function such as Figure 6 Block 404 outputs a heat exchanger heat gain value for the transmission fluid exiting the heat exchanger. The heat exchanger heat gain value is input to block 406 .

[0040] At box 406, a heat exchanger heat gain value for the transmission fluid exiting the heat exchanger, a transmission output temperature, and a commanded automatic transmission warm-up (ATWU) valve operating state are received as inputs to box 406. The inputs are applied to a reference table or function, such as Figure 7 Block 406 outputs a modeled or estimated transmission fluid temperature at the outlet of the heat exchanger (e.g., an estimate of the temperature sensed via temperature sensor 312), which includes compensation for the commanded ATWU state. The modeled or estimated transmission fluid temperature at the outlet of the heat exchanger is input to block 408.

[0041] At box 408, the modeled or estimated transmission fluid temperature at the outlet of the heat exchanger and the actual transmission fluid temperature at the outlet of the heat exchanger are received as inputs to box 408. The inputs are applied to a reference table or function such as Figure 8 Block 408 outputs a modeled or estimated transmission fluid temperature output from the heat exchanger (eg, an estimate of the temperature sensed via temperature sensor 312 ). The modeled or estimated transmission fluid temperature is input to block 410 .

[0042] At box 410, the modeled or estimated transmission fluid temperature at the outlet of the heat exchanger is compared to the actual transmission fluid temperature at the outlet of the heat exchanger. If the modeled or estimated transmission fluid temperature is greater than the actual transmission fluid temperature by more than a predetermined amount, box 410 indicates that the automatic transmission warm-up valve is degraded. Otherwise, box 410 indicates that the automatic transmission warm-up valve is not degraded. Box 410 outputs an indication of whether the automatic transmission warm-up valve is degraded to box 412.

[0043] At box 412, method 400 performs actions to alleviate degradation of the automatic transmission warm-up valve. Specifically, method 400 can adjust the human / machine interface to indicate that the automatic transmission warm-up valve is degraded. In addition, method 400 can adjust engine operation in response to degradation of the automatic transmission warm-up valve. Adjusting engine operation may include adjusting engine spark timing and adjusting engine poppet valve timing so that less engine heat can be discharged to the engine coolant during engine cold start, thereby improving system efficiency when less engine heat can be transferred to the transmission. For example, if there is degradation of the automatic transmission warm-up valve, the spark can be advanced more quickly after a cold start. In addition, if there is degradation of the automatic transmission warm-up valve, the exhaust valve timing can be advanced more quickly after a cold start of the engine.

[0044] If automatic transmission warm-up valve degradation is indicated, method 400 may also adjust transmission operation. For example, method 400 may adjust the transmission shift schedule so that the transmission clutch may take longer to close. Additionally, when automatic transmission warm-up valve degradation is indicated, adjustments to the torque converter clutch lockup schedule may be performed.

[0045] therefore, Figure 4 The method estimates a transmission fluid temperature and compares the estimated transmission fluid temperature to an actual transmission fluid temperature determined via a temperature sensor. If the estimated transmission fluid temperature is higher than the actual transmission fluid temperature when the automatic transmission warm-up valve is commanded to open, automatic transmission warm-up valve degradation may be indicated.

[0046] Now turn to Figure 5 , showing Figure 4 Detailed view of the contents of box 402 of FIG. Specifically, the engine speed (in revolutions per minute (RPM)) is input to box 502. Box 502 represents a one-dimensional table that outputs the engine coolant flow rate through the heat exchanger when the automatic transmission warm-up valve is fully open based on the engine speed input. The engine coolant flow rate is input into box 503.

[0047] Box 503 shows a two-dimensional table of transmission fluid specific heat acceptance values ​​for the output heat exchanger. The values ​​in the table are referenced by the engine coolant flow rate and the transmission fluid flow rate through the heat exchanger. The transmission fluid specific heat acceptance value is output from box 402 and has units of kilowatts per engine coolant inlet temperature difference relative to the engine coolant output temperature.

[0048] In this way, the operating characteristics of the heat exchanger are used to estimate the transmission fluid temperature. By applying the operating characteristics of the heat exchanger to estimate the transmission fluid temperature, the accuracy of the estimated transmission fluid temperature may be improved.

[0049] Reference now Figure 6, showing Figure 4 Detailed view of the contents of box 404 of FIG. Specifically, engine coolant temperature, transmission output temperature (e.g., Figure 4 The temperature of the transmission fluid at the location of the temperature sensor 314) and the transmission fluid specific heat acceptance value of the heat exchanger are received in box 404. The engine coolant temperature and the transmission output temperature are input to box 602. Box 602 represents an arithmetic box in which the engine coolant temperature is subtracted from the transmission output temperature. The result from box 602 is input to box 603 along with the transmission fluid specific heat acceptance value of the heat exchanger. Box 603 is a multiplication box that multiplies the result output from box 602 by the transmission fluid specific heat acceptance value of the heat exchanger. Box 603 outputs the result of the heat exchanger heat or temperature increase.

[0050] Move to Figure 7 , showing Figure 4 Detailed view of the contents of box 406 of FIG. Box 406 receives a constant (0), an operating state of an automatic transmission warm-up (ATWU) valve (e.g., open / closed), and a heat exchanger heat or temperature increase. In this example, box 702 is a switching box that outputs a value of one input (0) or a value of a second input (heat exchanger heat increase) to box 703 depending on the operating state of the automatic transmission warm-up valve. If the automatic transmission warm-up valve is closed, box 702 outputs a value of zero. If the automatic transmission warm-up valve is open, box 702 outputs a heat exchanger heat increase value. Box 703 applies a first-order low-pass filter to the value input to box 703, and box 703 outputs the filtered value to box 704. Box 704 multiplies the output of box 703 by a scalar value and outputs the result to box 706. At box 706, the transmission output temperature is added to the output of box 704 to generate a modeled transmission output fluid temperature.

[0051] Reference now Figure 8 , showing Figure 4 Detailed view of the contents of box 408 of FIG. Box 408 receives the modeled heat exchanger output transmission fluid temperature and the actual transmission fluid temperature as inputs to box 802. Box 802 is an arithmetic box that subtracts the actual transmission fluid temperature from the modeled heat exchanger output transmission fluid temperature, and it outputs the result to box 804. Box 804 applies a first order low pass filter to the output of box 802, and delivers the result to box 806, where the result is multiplied by a scalar value, and the result is supplied to box 808. Box 808 is another arithmetic box, and it adds the output of box 816 to the output of box 806, and the result is the value from the heat exchanger (e.g., Figure 3 of 304)'s estimated transmission fluid temperature output.

[0052] The system clock 810 and the constant are input to box 814. Box 812 represents a scalar constant value, and box 814 represents a greater than box that compares the output of the system clock 810 with the scalar value output from box 812. If the output of the system clock 801 is greater than the output of box 812, box 814 outputs a logical value of one. Otherwise, box 814 outputs a false or logical value of zero. Box 816 is a switching box that outputs a value corresponding to the output of box 820 or a value to the second input (transmission fluid temperature) to box 808 depending on the output of box 814. If the output of box 814 is a logical zero, box 816 outputs the output of box 820. If the output of box 814 is a logical one, box 816 outputs the transmission fluid temperature value. Box 820 is a time delay box whose output is delayed by one time step, and the output of box 808 is supplied to the input of box 820.

[0053] Now turn to Fig. 9 , showing Figure 4 Detailed view of the contents of box 410 of FIG. Box 410 receives an estimated transmission fluid temperature at the output of the heat exchanger, a commanded automatic transmission warm-up valve state, and an actual transmission fluid temperature at the output of the heat exchanger. If the estimated transmission fluid temperature at the output of the heat exchanger is greater than the actual transmission fluid temperature at the output of the heat exchanger by more than a predetermined temperature amount and the automatic transmission warm-up valve is commanded to open, box 902 outputs a logical one to indicate automatic transmission warm-up valve degradation. If the estimated transmission fluid temperature at the output of the heat exchanger is not greater than the actual transmission fluid temperature at the output of the heat exchanger by more than a predetermined temperature amount and the automatic transmission warm-up valve is commanded to open, box 902 outputs a logical zero to indicate no automatic transmission warm-up valve degradation. If the estimated transmission fluid temperature at the output of the heat exchanger is greater than the actual transmission fluid temperature at the output of the heat exchanger by more than a predetermined temperature amount and the automatic transmission warm-up valve is not commanded to open, box 902 outputs a logical zero to indicate no automatic transmission warm-up valve degradation. If the estimated transmission fluid temperature at the output of the heat exchanger is not greater than the actual transmission fluid temperature at the output of the heat exchanger by more than a predetermined temperature amount and the automatic transmission warm-up valve is commanded open, block 902 outputs a logical zero to indicate no automatic transmission warm-up valve degradation.

[0054] In this way, the frame Figure 4 To frame Fig. 9 The method may determine whether an automatic transmission warm-up valve is degraded or not degraded. The determination of degradation or not degraded may be based on a commanded position of the automatic transmission warm-up valve and an estimated transmission fluid temperature.

[0055] Figures 4 to 9A method for diagnosing the operation of a transmission warm-up valve is provided, the method comprising: estimating, via a controller, a temperature of a transmission fluid exiting a heat exchanger; and adjusting, via the controller, the operation of a device in response to a difference between the temperature and an actual temperature of the transmission fluid exiting the heat exchanger. In a first example, the method comprises: wherein estimating the temperature of the transmission fluid comprises adjusting the temperature in response to a specific heat acceptance value of the heat exchanger. In a second example, which may include the first example, the method comprises: wherein the specific heat acceptance value is a function of a flow rate of an engine coolant through the heat exchanger. In a third example, which may include one or both of the first and second examples, the method comprises: wherein the specific heat acceptance value is also based on a function of a flow rate of the transmission fluid through the heat exchanger. In a fourth example, which may include one or more of the first to third examples, the method comprises: wherein the device is a transmission. In a fifth example, which may include one or more of the first to fourth examples, the method comprises: wherein the device is an engine. In a sixth example, which may include one or more of the first to fifth examples, the method comprises: wherein the device is a human / machine interface. In a seventh example, which may include one or more of the first to sixth examples, the method includes: wherein the temperature is estimated based on a commanded position of the transmission warm-up valve.

[0056] Figures 4 to 9 A method for diagnosing the operation of a transmission warm-up valve is also provided, the method comprising: commanding the transmission warm-up valve to a predetermined state via a controller; and determining whether the transmission warm-up valve is in the predetermined state in response to an estimated temperature of a transmission fluid exiting a heat exchanger. In a first example, the method comprises: wherein the estimated temperature of the transmission fluid is compared to an actual temperature of the transmission fluid. In a second example, which may include the first example, the method comprises: wherein when the estimated temperature of the transmission fluid exceeds the actual temperature of the transmission fluid by a predetermined temperature, it is determined that the transmission warm-up valve is degraded. In a third example, which may include one or both of the first and second examples, the method further comprises adjusting the operation of a transmission or an engine in response to whether the transmission warm-up valve is determined to be in the predetermined state. In a fourth example, which may include one or more of the first to third examples, the method comprises: wherein the predetermined state is an open state.

[0057] Reference now Fig.10 , showing that according to Figures 4 to 9 An exemplary vehicle operation sequence of the method of Figures 1 to 3 system and Figures 4 to 9 The method collaborates to generate Fig.10 sequence of operations. Figure 1 0 are time aligned and the vertical lines indicate the times of interest in the sequence.

[0058] since Fig.10 The first graph from the top of FIG. 1002 is a graph of engine coolant temperature versus time. The vertical axis represents engine coolant temperature, and engine coolant temperature increases in the direction of the vertical axis arrow. The horizontal axis represents time and the amount of time increases from the left side of the graph to the right side of the graph. Trace 1002 represents engine coolant temperature.

[0059] from Fig.10 The second graph from the top of is a graph of engine coolant temperature versus time. The vertical axis represents engine coolant temperature, and the engine coolant temperature increases in the direction of the vertical axis arrow. The horizontal axis represents time and the amount of time increases from the left side of the graph to the right side of the graph. Trace 1004 represents the engine coolant temperature.

[0060] from Fig.10 The third graph from the top of FIG. 1006 is a graph of the estimated or modeled transmission fluid temperature at the outlet of the engine coolant-transmission fluid heat exchanger. The vertical axis represents the estimated or modeled transmission fluid temperature at the outlet of the engine coolant-transmission fluid heat exchanger, and the estimated or modeled transmission fluid temperature increases in the direction of the vertical axis arrow. The horizontal axis represents time and the amount of time increases from the left side of the graph to the right side of the graph. Trace 1006 represents the estimated or modeled transmission fluid temperature at the outlet of the engine coolant-transmission fluid heat exchanger.

[0061] from Fig.10 The fourth graph from the top of is a graph of commanded automatic transmission warm-up valve operating state versus time. The vertical axis represents the commanded automatic transmission warm-up valve operating state, and when trace 1008 is near the vertical axis arrow, the automatic transmission warm-up valve is commanded to be open. When trace 1008 is near the horizontal axis, the automatic transmission warm-up valve is commanded to be closed. The horizontal axis represents time and the amount of time increases from the left side of the graph to the right side of the graph. Trace 1008 represents the commanded automatic transmission warm-up valve operating state.

[0062] from Fig.10The fifth graph from the top of is a graph of the degradation state of the automatic transmission warm-up valve relative to time. The vertical axis represents the degradation state of the automatic transmission warm-up valve, and when the trace 1010 is near the vertical axis arrow, it is determined that the automatic transmission warm-up valve is degraded. When the trace 1010 is near the horizontal axis, it is determined that the automatic transmission warm-up valve is not degraded. The horizontal axis represents time and the amount of time increases from the left side of the graph to the right side of the graph. Trace 1010 represents the degradation state of the automatic transmission warm-up valve.

[0063] At time t0, the engine is cold started and the engine coolant temperature begins to rise. The automatic transmission warm-up valve is fully closed to allow the engine to warm up faster than when the automatic transmission warm-up valve is open so that engine emissions can be reduced. As the engine spins the torque converter, which begins to heat the transmission fluid, the modeled transmission fluid temperature and the actual transmission fluid temperature begin to gradually increase. The automatic transmission warm-up valve is not indicated as degraded.

[0064] At time t1, the engine coolant temperature reaches a threshold temperature, causing the controller to command the automatic transmission warm-up valve to fully open. The modeled or estimated transmission fluid temperature at the outlet of the engine coolant-transmission fluid heat exchanger begins to increase at a faster rate. The automatic transmission warm-up valve remains commanded in a fully open state and it is not indicated as degraded.

[0065] At time t2, the engine coolant temperature has leveled off and the modeled transmission fluid temperature at the outlet of the engine coolant-transmission fluid heat exchanger has increased much faster than the actual transmission fluid temperature, which results in the automatic transmission warm-up valve being determined to be degraded. The automatic transmission warm-up valve remains in the commanded fully open state, but the automatic transmission warm-up valve is indicated as degraded because the actual temperature of the transmission fluid is significantly lower than the estimated or modeled automatic transmission fluid temperature, which may indicate that the valve is not open.

[0066] In this way, the automatic transmission warm-up valve may be diagnosed as non-degraded or degraded. The determination may be based on the commanded valve state and the temperature of the transmission fluid exiting the engine coolant-transmission fluid heat exchanger.

[0067] As will be appreciated by those of ordinary skill in the art, the methods described herein may represent one or more of any number of processing strategies, such as event-driven, interrupt-driven, multi-tasking, multi-threaded, and the like. To this end, the various steps or functions shown may be performed in the sequence shown, in parallel, or in some cases omitted. Likewise, the order of processing is not necessarily required to achieve the objectives, features, and advantages described herein, but is provided for ease of illustration and description. Although not explicitly shown, those of ordinary skill in the art will recognize that one or more of the steps or functions shown may be repeatedly performed depending on the specific strategy used. In addition, the described actions, operations, methods, and / or functions may be graphically represented by code to be programmed into a non-transitory memory of a computer-readable storage medium in an engine control system.

[0068] This description ends here. Many variations and modifications will occur to those skilled in the art after reading this specification without departing from the spirit and scope of this specification. For example, I3, I4, I5, V6, V8, V10 and V12 engines operating in natural gas, gasoline, diesel or alternative fuel configurations may benefit from using this specification.

[0069] According to the present invention, a method for diagnosing the operation of a transmission warm-up valve includes: estimating, via a controller, a temperature of transmission fluid leaving a heat exchanger; and adjusting, via the controller, the operation of a device in response to a difference between the temperature and an actual temperature of the transmission fluid leaving the heat exchanger.

[0070] In one aspect of the present invention, estimating said temperature of the transmission fluid includes adjusting said temperature in response to a specific heat acceptance value of said heat exchanger.

[0071] In one aspect of the invention, the specific heat acceptance value is a function of the engine coolant flow rate through the heat exchanger.

[0072] In one aspect of the present invention, the specific heat acceptance value is further based on a transmission fluid flow rate through the heat exchanger.

[0073] In one aspect of the invention, the device is a transmission.

[0074] In one aspect of the invention, the device is an engine.

[0075] In one aspect of the invention, the device is a human / machine interface.

[0076] In one aspect of the present invention, said temperature is estimated based on a commanded position of said transmission warm-up valve.

[0077] According to the present invention, a transmission heating system is provided, which has: an internal combustion engine; an automatic transmission; a heat exchanger; an automatic transmission preheating valve; and a controller, the controller including executable instructions stored in a non-volatile memory, the executable instructions causing the controller to generate an estimated value of the temperature of the transmission fluid leaving the heat exchanger and a comparison with the actual temperature of the transmission fluid leaving the heat exchanger, and adjust the operation of the automatic transmission or the internal combustion engine in response to the comparison.

[0078] According to an embodiment, the estimate of the temperature of the transmission fluid is based on a commanded state of the automatic transmission warm-up valve.

[0079] According to an embodiment, the estimated value of the temperature of the transmission fluid is also based on a specific heat acceptance value of the heat exchanger.

[0080] According to an embodiment, the estimate of the temperature of the transmission fluid is further based on an engine coolant temperature.

[0081] According to an embodiment, the estimated value of the temperature of the transmission fluid is also based on the engine speed.

[0082] According to an embodiment, adjusting operation of the automatic transmission includes modifying a transmission shift schedule.

[0083] According to an embodiment, adjusting operation of the internal combustion engine comprises adjusting engine valve timing.

[0084] According to the present invention, a method for diagnosing the operation of an automatic transmission preheating valve includes: commanding the automatic transmission preheating valve to a predetermined state via a controller; and determining whether the automatic transmission preheating valve is in the predetermined state in response to an estimated temperature of a transmission fluid leaving a heat exchanger.

[0085] In one aspect of the present invention, the estimated temperature of the transmission fluid is compared to an actual temperature of the transmission fluid.

[0086] In an aspect of the present invention, when the estimated temperature of the transmission fluid exceeds the actual temperature of the transmission fluid by a predetermined temperature, it is determined that the automatic transmission warm-up valve is degraded.

[0087] In one aspect of the present invention, the method further includes adjusting operation of a transmission or an engine in response to whether the automatic transmission warm-up valve is determined to be in the predetermined state.

[0088] In one aspect of the invention, the predetermined state is an open state.

Claims

1. A method for diagnosing operation of a transmission warm-up valve, comprising: estimating, via the controller, a temperature of the transmission fluid exiting the heat exchanger; as well as Operation of a device is adjusted via the controller in response to a difference between the temperature and an actual temperature of the transmission fluid exiting the heat exchanger. 2 . The method of claim 1 , wherein estimating the temperature of the transmission fluid comprises adjusting the temperature in response to a specific heat acceptance value of the heat exchanger. 3 . The method of claim 2 , wherein the specific heat acceptance value is a function of an engine coolant flow rate through the heat exchanger. 4 . The method of claim 3 , wherein the specific heat acceptance value is further based on a transmission fluid flow rate through the heat exchanger.

5. The method of claim 2, wherein the device is a transmission.

6. The method of claim 2, wherein the device is an engine.

7. The method of claim 2, wherein the device is a human / machine interface. The method of claim 1 , wherein the temperature is estimated based on a commanded position of the transmission warm-up valve.

9. A transmission heating system, comprising: Internal combustion engines; Automatic transmission; Heat exchangers; Automatic transmission preheating valve; as well as a controller including executable instructions stored in a non-transitory memory that causes the controller to generate a comparison of an estimate of the temperature of the transmission fluid exiting the heat exchanger and an actual temperature of the transmission fluid exiting the heat exchanger and to adjust operation of the automatic transmission or the internal combustion engine in response to the comparison. 10 . The transmission warming system of claim 9 wherein said estimate of said temperature of said transmission fluid is based on a commanded state of said automatic transmission warm-up valve. 11 . The transmission warming system of claim 10 , wherein said estimate of said temperature of said transmission fluid is further based on a specific heat acceptance value of said heat exchanger. 12 . The transmission warming system of claim 11 wherein said estimate of said temperature of said transmission fluid is further based on an engine coolant temperature. 13 . The transmission warming system of claim 12 wherein said estimate of said temperature of said transmission fluid is further based on engine speed.

14. The transmission warming system of claim 9, wherein adjusting operation of the automatic transmission includes modifying a transmission shift schedule.

15. The transmission warming system of claim 9, wherein adjusting operation of the internal combustion engine includes adjusting engine valve timing.

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