Vehicle diagnostic method for vehicle

Abstract

A vehicle diagnostic method for a vehicle is disclosed. The vehicle includes an internal combustion engine and a continuously variable transmission operably coupled to the internal combustion engine, the method comprising the steps of: using a monitoring circuit to determine at least one operating parameter received from one or more sensors associated with the operation of the continuously variable transmission; using a detection circuit to detect at least one critical belt life event of a drive belt of the continuously variable transmission; using an alarm circuit to determine when the at least one detected critical belt life event is related to a failure of the drive belt of the continuously variable transmission based on the at least one operating parameter; and using the alarm circuit to generate an information signal related to the life of the drive belt.

Description

[0001] This application is a divisional application of the application with national application number 201880006668.3, international application date January 22, 2018, national entry date July 11, 2019, and invention name “Diagnostic system and method for continuously variable transmission”.

[0002] Related Applications

[0003] This application claims the benefit of U.S. Provisional Application No. 62 / 448,875, filed on January 20, 2017, entitled “DIAGNOSTIC SYSTEMS AND METHODS OFA CONTINUOUSLY VARIABLE TRANSMISSION,” the entire disclosure of which is expressly incorporated herein by reference. Technical Field

[0004] The present disclosure relates generally to vehicle diagnostic systems and, more particularly, to a diagnostic system for a drive belt in a continuously variable transmission (CVT). Background Art

[0005] Conventional vehicles, including utility vehicles and side-by-side vehicles, have internal combustion engines that generate drive torque. To drive the engine's pistons, an air / fuel mixture is burned within a cylinder, and the air / fuel mixture is regulated via an intake valve and an exhaust valve. The intake valve is selectively opened to draw air into the cylinder, and the air is mixed with fuel to form an air / fuel mixture. To allow exhaust gas to be discharged from the cylinder after combustion, the exhaust valve is selectively opened at a specific time.

[0006] Continuously variable transmissions (CVTs) are commonly installed in recreational vehicles such as snowmobiles and all-terrain vehicles. The CVT provides a myriad of different gears effective in transferring torque from the engine to an output driveline of the transmission. The output driveline operably couples the transmission to at least one ground engaging member.

[0007] However, due to the belt structure of the CVT, one of the disadvantages is that the drive belt of the CVT tends to wear and become damaged prematurely when the drive belt is not properly broken in or is overused under unexpected conditions. Because the drive belt only transmits engine power from the drive pulley of the CVT to the driven pulley, the drive belt is an important component of the CVT. Typically, the CVT drive belt is a V-belt and is made of rubber, usually fiber-reinforced, which is rigid but flexible along its length. During operation, the drive belt is subject to extreme pressure and friction.

[0008] When the drive belt loses pressure between the pulleys of the CVT under high load or overload conditions, slippage may occur causing belt damage such as spin burn or hour-glassing events. For example, during a spin burn event, belt temperatures can quickly reach over 200 degrees Fahrenheit (℉) without any warning, and if no remedial action is taken, belt temperatures can continue to rise to 400℉. At that point, the drive belt is irreparably damaged, and without replacing the damaged drive belt, the vehicle cannot be operated, thereby incurring increased maintenance costs and repair time.

[0009] Therefore, there is an opportunity to develop improved diagnostic systems and methods that can automatically detect or predict failure of a drive belt prior to potential belt damage. Summary of the invention

[0010] As discussed in more detail below, the exemplary diagnostic system provides enhanced diagnostic functionality for detecting faults of a CVT belt using various circuits and other related systems.In the exemplary diagnostic system and method, monitoring of operating parameters and fault detection of a CVT belt are performed automatically.

[0011] The present disclosure also includes systems and methods configured to monitor patterns of operating parameter changes during a predetermined time period based on historical information of a comparison logic or algorithm. In addition, the present diagnostic system provides an enhanced display and relationship of operating parameters in real time. In addition, the operating parameters are automatically displayed without a large number of manual interruptions. Therefore, the overall operating time of the engine system is enhanced without incurring additional operating expenses and maintenance costs.

[0012] In one exemplary embodiment, a vehicle diagnostic method for a vehicle is provided, the vehicle including an internal combustion engine and a continuously variable transmission (CVT) operably coupled to the internal combustion engine. The method includes the following steps: using a detection circuit to detect at least one engine crankshaft acceleration change event of the vehicle; using a monitoring circuit to determine at least one operating parameter received from one or more sensors associated with the operation of the CVT; and using an alarm circuit to determine when at least one detected engine crankshaft acceleration change is related to a fault of a drive belt of the CVT based on at least one operating parameter. In one example, the diagnostic method also includes including an environmental condition parameter as at least one operating parameter, wherein the environmental condition parameter includes at least one of a fuel state signal, an engine coolant temperature signal, a drive belt temperature signal, and a clutch state signal. In another example, the diagnostic method also includes including an engine-based parameter as at least one operating parameter, wherein the engine-based parameter is related to at least one of a crankshaft acceleration signal, an engine torque signal, and a transmission gear signal. In yet another example, the diagnostic method also includes including a transmission-based parameter as at least one operating parameter, wherein the transmission-based parameter is related to at least one of a vehicle speed signal, an engine speed signal, and a wheel speed signal. In yet another example, the diagnostic method further includes detecting at least one engine crankshaft acceleration change event by measuring an acceleration rate or a deceleration rate of the crankshaft acceleration signal. In yet another example, the diagnostic method further includes detecting at least one engine crankshaft acceleration change event based on a change pattern of an operating parameter measured during a predetermined time period. In a variation thereof, the diagnostic method further includes determining whether the frequency of the change pattern is greater than a predetermined threshold. In another variation thereof, the diagnostic method further includes determining whether the pattern time period of the change pattern is greater than a predetermined time period. In a refinement of its variation, the diagnostic method further includes determining whether the size of the change pattern. In yet another example, the diagnostic method further includes executing a first correction method, the first correction method being used to determine whether the engine crankshaft acceleration change event is caused by a belt slip event or an engine combustion misfire event based on a single occurrence of at least one engine crankshaft acceleration change event. In yet another example, the diagnostic method further includes executing a second correction method, the second correction method being used to determine whether the engine crankshaft acceleration change event is caused by a belt slip event or an engine combustion misfire event based on multiple occurrences of at least one engine crankshaft acceleration change event.

[0013] In another exemplary embodiment, a vehicle diagnostic method for a vehicle is provided, the vehicle including an internal combustion engine and a continuously variable transmission (CVT) operably coupled to the internal combustion engine. The method includes the steps of: using a monitoring circuit to determine at least one operating parameter received from one or more sensors associated with the operation of the CVT; using a detection circuit to detect at least one belt slip event of a drive belt of the CVT; using an alarm circuit to determine when at least one detected belt slip event is associated with an impending failure of the drive belt of the CVT based on at least one operating parameter; and using the alarm circuit to notify of an impending failure of the drive belt before damage to the belt or driveline of the vehicle occurs. In one example, the diagnostic method also includes generating an information signal related to an impending failure of the drive belt. In another example, the diagnostic method also includes providing an option to override a user input by adjusting at least one value of at least one operating parameter. In yet another example, the diagnostic method also includes detecting at least one belt slip event by the detection circuit in at least one of a retroactive control mode and an active control mode. In yet another example, the diagnostic method also includes receiving a desired vehicle input parameter using the monitoring circuit. In yet another example, the diagnostic method also includes including an environmental condition parameter as at least one operating parameter. In yet another example, the diagnostic method further includes including an engine-based parameter as at least one operating parameter. In yet another example, the diagnostic method further includes including a driveline-based parameter as at least one operating parameter. In yet another example, the diagnostic method further includes detecting a belt slip event based on a comparison of the engine-based parameter and the driveline-based parameter for predicting an impending failure of the drive belt. In a variation thereof, the diagnostic method further includes determining whether at least one of the engine-based parameter and the driveline-based parameter is greater than a predetermined threshold. In another example, the diagnostic method further includes notifying at least one detected belt slip event using a display; and automatically adjusting at least one operating parameter based on a predetermined table.

[0014] In another exemplary embodiment, a vehicle diagnostic method for a vehicle is provided, the vehicle including an internal combustion engine and a continuously variable transmission (CVT) operably coupled to the internal combustion engine. The method includes the following steps: using a monitoring circuit to determine at least one operating parameter received from one or more sensors associated with the operation of the CVT; using a detection circuit to detect at least one critical belt life event of a drive belt of the CVT; using an alarm circuit to determine when at least one detected critical belt life event is related to a failure of the drive belt of the CVT based on at least one operating parameter; and using the alarm circuit to generate an information signal related to the life of the drive belt. In an example, the diagnostic method also includes including an environmental condition parameter as at least one operating parameter, wherein the environmental condition parameter includes a temperature signal. In another example, the diagnostic method also includes including an engine-based parameter as at least one operating parameter, wherein the engine-based parameter is related to at least one of an engine load signal, a throttle position signal, an engine torque signal, and an engine power signal. In yet another example, the diagnostic method also includes including a transmission-based parameter as at least one operating parameter, wherein the transmission-based parameter is related to at least one of a vehicle speed signal and an engine speed signal. In yet another example, the diagnostic method further includes detecting a critical belt life event based on a comparison of an engine-based parameter, a drive train-based parameter, and an ambient condition parameter; and predicting a remaining life of the drive belt based on the comparison. In a variation thereof, the diagnostic method further includes determining whether the remaining life of the drive belt is less than a predetermined threshold. In another variation thereof, the diagnostic method further includes displaying an information signal on a display using a text or graphical indication associated with the remaining life of the drive belt. In another example, the diagnostic method further includes adjusting at least one of the engine-based parameter, the drive train-based parameter, and the ambient condition parameter based on at least one detected critical belt life event.

[0015] In another exemplary embodiment of the present disclosure, a vehicle diagnostic method for a vehicle is provided, the vehicle including an internal combustion engine and a continuously variable transmission (CVT) operably coupled to the internal combustion engine. The method includes the following steps: determining the amount of input energy provided by the internal combustion engine to the CVT; determining the amount of output heat energy leaving the CVT; determining the amount of accumulated energy in the CVT based on the amount of input energy and the amount of output heat energy; comparing the amount of accumulated energy with a threshold; and reducing the amount of input energy in response to the amount of accumulated energy satisfying the threshold. In an example thereof, the step of reducing the amount of input energy includes the step of reducing the power provided by the internal combustion engine to the CVT. In another example, the amount of input energy is determined based on the mechanical input characteristics of the CVT. In yet another example, the amount of output heat energy is determined based on the fluid characteristics of the CVT. In yet another example, the step of determining the amount of input energy provided by the internal combustion engine to the CVT includes the following steps: determining the output power of the internal combustion engine; determining the CVT clutch efficiency based on the determined output power; and determining the amount of input energy provided to the CVT based on the determined output power and the determined CVT clutch efficiency. In a variation thereof, the step of determining the CVT clutch efficiency based on the determined output power includes the step of retrieving the determined CVT clutch efficiency from a database. In yet another example, the step of determining the output heat energy leaving the CVT includes the steps of: determining an air temperature of air entering an interior of the CVT; and determining the amount of output heat energy leaving the CVT based on a CVT clutch airflow model, a heat transfer coefficient, and the determined air temperature.

[0016] In another exemplary embodiment of the present disclosure, a vehicle diagnostic method for a vehicle is provided, the vehicle including an internal combustion engine and a continuously variable transmission (CVT) operably coupled to the internal combustion engine. The method includes the following steps: detecting a plurality of engine crankshaft acceleration change events; determining the frequency of the plurality of engine crankshaft acceleration change events; determining the CVT belt interaction frequency of a drive belt of the CVT; and classifying the plurality of engine crankshaft acceleration change events as one of an engine misfire event and a CVT belt damage event based on a comparison of the frequency with the CVT belt interaction frequency. In an example thereof, the step of determining the CVT belt interaction frequency of the drive belt of the CVT includes the following steps: determining the pitch diameter of the transmission clutch of the CVT; determining the linear speed of the drive belt of the CVT based on the determined pitch diameter of the transmission clutch and the rotational speed of the drive shaft of the CVT; and determining the CVT belt interaction frequency of the drive belt based on the determined linear speed of the drive belt of the CVT and the length of the belt.

[0017] In yet another exemplary embodiment of the present disclosure, a vehicle diagnostic system for diagnosing a drive belt of a continuously variable transmission is provided. A diagnostic circuit detects or predicts a failure of the drive belt based on operating parameters received from sensors associated with the vehicle during a predetermined diagnostic period.

[0018] Additional features and advantages of the present disclosure will become apparent to those skilled in the art upon consideration of the following detailed description of exemplary embodiments, which illustrate the best presently contemplated modes of carrying out the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The embodiments will be more readily understood in view of the following description when taken in conjunction with the following drawings, and in which like reference numerals represent like elements, wherein:

[0020] Figure 1 A representative diagram of a powertrain of an exemplary side-by-side vehicle is shown;

[0021] Figure 2 A representative diagram showing initial air flow for an exemplary continuously variable transmission (CVT);

[0022] Figure 3 Exemplary block diagrams and schematics of one illustrative embodiment of a diagnostic system having engine control circuitry and diagnostic circuitry are shown.

[0023] Figure 4 An exemplary processing sequence for executing the present diagnostic system for detecting a belt slip event in a retroactive control mode is shown;

[0024] Figure 5 An exemplary processing sequence for executing the present diagnostic system for detecting a belt slip event in a look-ahead control mode is shown;

[0025] Figure 6 An exemplary processing sequence for executing the present diagnostic system for detecting critical belt life events is shown;

[0026] Figure 7 An exemplary processing sequence for executing the present diagnostic system for detecting an engine misfire event is shown;

[0027] Figure 8 An exemplary processing sequence for executing the present diagnostic system for detecting an engine misfire event or damaged belt event is shown;

[0028] Fig. 9 An exemplary processing sequence for determining the interaction frequency of a CVT belt is shown;

[0029] Fig.10 An exemplary processing sequence for regulating the peak output power of a power source based on accumulated energy in a CVT is shown;

[0030] Fig.11 An exemplary process sequence for determining an amount of energy input into a CVT during operation of the CVT is shown; and

[0031] Fig.12 An exemplary process sequence for determining an amount of energy exiting a CVT during operation of the CVT is shown.

[0032] Throughout the several figures, corresponding reference numerals indicate corresponding parts. Although the drawings represent embodiments of the present disclosure, the drawings are not necessarily drawn to scale, and certain features may be exaggerated to better illustrate and explain the present disclosure. The examples set forth herein illustrate exemplary embodiments of the present disclosure in one form, and such examples should not be construed as limiting the scope of the present disclosure in any way. DETAILED DESCRIPTION

[0033] The embodiments disclosed below are not intended to be exhaustive or to limit the invention to the precise forms disclosed in the following detailed description. Rather, these embodiments are selected and described so that others skilled in the art can utilize their teachings. Although the present disclosure is primarily directed to a continuously variable transmission ("CVT"), it should be understood that the features disclosed herein can be incorporated into one or more vehicles. Exemplary vehicles include all-terrain vehicles, side-by-side UTVs, utility vehicles, motorcycles, snowmobiles, golf carts, and other vehicles or devices incorporating a continuously variable transmission.

[0034] Now refer to Figure 1 , a representative diagram of a vehicle 100 is shown. The vehicle 100 as shown includes a plurality of ground engaging members 102. Illustratively, the ground engaging members 102 are wheels 104 with associated tires. Other exemplary ground engaging members include skis and tracks. In one embodiment, one or more of the wheels may be replaced with tracks, such as the Prospector II tracks available from Polaris Industries, Inc. located at 2100 Highway 55, Medina, Minnesota 55340.

[0035] One or more of the ground engaging members 102 may be operably coupled to a shiftable transmission 130 for providing power for movement of the vehicle 100. Other suitable types of transmissions, such as non-shiftable gear sets, are also contemplated. Exemplary power sources 106 include internal combustion engines and electric motors. In the illustrated embodiment, the power source 106 is an internal combustion engine.

[0036] Internal combustion power source 106 such as Figure 1As shown. The power source 106 receives fuel from a fuel source 108 and ambient air from an intake system 110. For example, ambient air is selectively supplied to the power source 106 to mix with the fuel for internal combustion. Exhaust gas is discharged from the power source 106 through the exhaust system 112. The output shaft 120 of the power source 106 is coupled to a transmission member of a continuously variable transmission ("CVT unit") 122. The driven member of the CVT unit 122 is operably coupled to the transmission member of the CVT unit 122 via a drive belt. The CVT unit 122 receives ambient air through an intake system 124, and exhausts air from the interior of the CVT unit 122 through an exhaust system 126. The driven member is coupled to an output shaft 128, which is operably coupled to the input end of a shiftable transmission 130.

[0037] The first output shaft 132 of the shiftable transmission 130 is coupled to a rear drive unit 134. The rear drive unit 134 is coupled to the corresponding wheels 104 of a rear axle 136 via half shafts 138. The rear drive unit 134 may be a differential. The second output shaft 140 of the shiftable transmission 130 is coupled to a front drive unit 142. The front drive unit 142 is coupled to the corresponding wheels 104 of a front axle 144 via half shafts 138. The front drive unit 142 may be a differential.

[0038] Various configurations of the rear drive unit 134 and the front drive unit 142 are contemplated. With respect to the rear drive unit 134, in one embodiment, the rear drive unit 134 is a locked differential, wherein power is provided to both wheels of the shaft 136 via the output shaft 150. In one embodiment, the rear drive unit 134 is a lockable / unlockable differential with respect to the output shaft 150. When the rear drive unit 134 is in the locked configuration, power is provided to both wheels of the shaft 136 via the output shaft 150. When the rear drive unit 134 is in the unlocked configuration, power is provided to one of the wheels of the shaft 136, such as a wheel with less resistance relative to the ground, via the output shaft 150. With respect to the front drive unit 142, in one embodiment, the front drive unit 142 has: a first configuration, wherein power is provided to both wheels of the front shaft 144; and a second configuration, wherein power is provided to one of the wheels of the shaft 144, such as a wheel with less resistance relative to the ground.

[0039] In one embodiment, the front drive unit 142 includes active descent control ("ADC"). ADC is a drive system that provides on-demand torque transfer to the front wheels when one of the wheels 104 of the rear axle 136 loses traction, and provides engine braking torque to the wheels 104 of the front axle 144. Both the on-demand torque transfer and engine braking features of the front drive unit 142 can be active or inactive. In the case of on-demand torque transfer, when active, power is provided to both wheels of the front axle 144, and when inactive, power is provided to one of the wheels of the front axle 144. In the case of engine braking, when active, engine braking is provided to the wheels of the front axle 144, and when inactive, engine braking is not provided to the wheels of the front axle 144. Other suitable arrangements are contemplated for the two-wheel drive system to accommodate the application. Exemplary front drive units are disclosed in U.S. patent application serial number 12 / 816,052, filed on June 15, 2010, entitled “ELECTRIC VEHICLE,” U.S. Patent No. 5,036,939, and U.S. Patent RE38,012E, the disclosures of which are expressly incorporated herein by reference.

[0040] In one embodiment, one or more of the CVT unit 122, the intake system 124, and the exhaust system 126 include sensors 160 that monitor the characteristics of the air inside the corresponding CVT unit 122, the intake system 124, and the exhaust system 126. In the illustrated embodiment, a plurality of sensors 160 are operably and communicatively connected to the transmission 130, the wheels 104, the intake system 124, the exhaust system 126, and the CVT unit 122 for receiving a signal from at least one of the connected sensors. Exemplary sensors include temperature sensors, speed sensors, and load sensors. In one embodiment, the sensors 160 provide an indication of the temperature of the air inside the corresponding CVT unit 122, the intake system 124, and the exhaust system 126 to an engine control circuit (ECC) 162 that includes logic for controlling the operation of the power source 106. When the monitored air temperature exceeds a threshold amount, the ECC 162 responds to the operator of the vehicle 100 through a user interface such as a meter 164 or a display 165 in the operator area of ​​the vehicle 100 by at least one of limiting the output speed of the output shaft 120 of the power source 106, limiting the speed of the vehicle 100, and indicating an overheat condition. An exemplary user interface is disclosed in U.S. Patent Application No. 15 / 161,720, filed on May 23, 2016, entitled "DISPLAY SYSTEMS AND METHODS FOR A RECREATIONAL VEHICLE", Docket No. PLR-12-27457-01P-US-E, the entire disclosure of which is expressly incorporated herein by reference. Exemplary indications of an overheat condition include a light, a warning message on the display 165, and other suitable means of communicating the condition to the operator. By limiting the engine speed or the vehicle speed, the temperature of the air inside the CVT unit 122 is reduced, and the temperature of the drive belt inside the CVT unit 122 is reduced. This reduces the risk of drive belt failure.

[0041] Reference Figure 2 , an exemplary continuously variable transmission 200 is shown. The continuously variable transmission 200 includes a transmission clutch 202 operably coupled to the output shaft 120, a driven clutch 204 operably coupled to the output shaft 128, and a drive belt 206 operably coupled to the transmission clutch 202 and the driven clutch 204 to transfer power from the transmission clutch 202 to the driven clutch 204. The transmission clutch 202 includes a first transmission clutch pulley 208 and a second transmission clutch pulley 210 movable relative to the first transmission clutch pulley 208. The driven clutch 204 includes a first driven clutch pulley 212 and a second driven clutch pulley 214 movable relative to the first driven clutch pulley 212.

[0042] Both the driving clutch 202 and the driven clutch 204 are positioned within a housing 220 having an interior 222. The housing 220 can include multiple components that cooperate to form the housing 220. The multiple components can also include features that direct air flow through the interior 222 of the housing 220. In one example, the housing 220 includes a base and a cover coupled to the base, the base having a first opening adapted to receive the driving shaft 120 and a second opening adapted to receive the driven shaft 128. The cover and the base cooperate to define the interior 222 of the housing 220. The cover and the base can include features that direct air flow through the interior 222 of the housing 220.

[0043] like Figure 2 As shown, one or more air supply ducts 230 are coupled to the housing 220. An exemplary air supply duct includes a hose. In one embodiment, each air supply duct 230 provides air to the interior 222 of the housing 220 through a corresponding air supply opening 232 in the exterior 234 of the housing 220. The air supply duct 230 provides air to the interior 222 of the housing 220 to cool the transmission clutch 202, the driven clutch 204, and the transmission belt 206. Therefore, this configuration provides a cooling effect on the transmission belt 206. The supplied air is directed toward one or more of the first transmission clutch pulley 208, the second transmission clutch pulley 210, the first driven clutch pulley 212, and the second driven clutch pulley 214, wherein the supplied air will absorb heat to cool the corresponding first transmission clutch pulley 208, the second transmission clutch pulley 210, the first driven clutch pulley 212, and the second driven clutch pulley 214. One or more. The air will then circulate within the interior 222 of the housing 220, potentially or intentionally contacting one or more of the first drive clutch pulley 208, the second drive clutch pulley 210, the first driven clutch pulley 212, and the second driven clutch pulley 214, and then exit the interior 222 of the housing 220 through one or more air discharge openings 236 in the wall 234 of the housing 220. One or more exhaust or outlet ducts 238 are coupled to the exhaust openings 236.

[0044] Reference Figure 3 , an exemplary schematic diagram of a diagnostic system 300 is shown. Included in the diagnostic system 300 is an engine control circuit (ECC) 162 having a diagnostic circuit (DC) 302. The DC 302 is configured to detect or predict a failure of the drive belt 206 of the CVT 122 based on at least one operating parameter, such as an engine or vehicle parameter or signal. Although the DC 302 is shown inside the ECC, the DC may be independent of or separate from the ECC, or incorporated into any other system of the vehicle 100 to suit the application.

[0045] The failure of the drive belt 206 may refer to a deteriorated condition of the drive belt caused by a rotational burnout or a timing hourglass event. For example, during substantial rotation of the drive pulley relative to the nearly stationary drive belt, slippage in the drive belt 206 may produce a timing hourglass event that changes the side profile of the drive belt 206 into a timing hourglass shape. By way of example only, when the wheel 104 is stuck in a ditch or loose soil such as mud or snow, the engine speed may increase, but the wheel speed may decrease to almost zero. This lack of rotational motion of the wheel 104 may cause the driven shaft 128 to stop and cause a timing hourglass event on the drive belt 206.

[0046] In the illustrated embodiment, the DC 302 is microprocessor-based and includes a non-transitory computer-readable medium or database 304 including processing instructions stored therein that are executable by the microprocessor of the DC 302 to control the operation of the diagnostic process of the CVT 122. The non-transitory computer-readable medium or memory may include a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (e.g., EPROM, EEPROM, or flash memory), or any other tangible medium capable of storing information. For example, a predetermined calibration or empirical lookup table may be stored on a volatile or non-volatile memory for subsequent access.

[0047] Exemplary operating parameters relate to engine speed (e.g., revolutions per minute (RPM)), engine load (e.g., units of percent relative load (%RL)), throttle position (e.g., percent throttle position), engine torque (e.g., inch-pounds or inch-ounces), engine power, etc. Other suitable operating parameters are also contemplated to suit different applications. Figures 4 to 7 Detailed descriptions of exemplary operating parameters and signals are provided in the relevant paragraphs.

[0048] As used herein, the term "circuit" or "unit" may refer to a part of or include an application specific integrated circuit (ASIC) that executes one or more software or firmware programs, an electronic circuit, a processor or microprocessor (shared, dedicated, or group) and / or memory (shared, dedicated, or group), a combinational logic circuit, and / or other suitable components that provide the described functionality. Therefore, while the present disclosure includes specific examples and arrangements of circuits, the scope of the present system should not be limited thereto as other modifications will become apparent to those skilled in the art.

[0049] The term "logic" as used herein includes software and / or firmware executed on one or more circuits. Thus, depending on the implementation, the various logics may be implemented in any suitable manner and will remain in accordance with the implementations disclosed herein. Non-transitory machine-readable media including logic may additionally be considered to be embodied in any tangible form of a computer-readable carrier such as a solid-state memory, a magnetic disk, and an optical disk, which contains appropriate computer instructions and data structure groups that will cause a processor to perform the techniques described herein.

[0050] The present disclosure contemplates other embodiments in which the DC 302 is not microprocessor-based, but is instead configured to regulate the operation of the diagnostic process of the CVT 122 based on one or more sets of hardwired instructions and / or software instructions stored in the database 304. Furthermore, the DC 302 may be contained within a single device or may be multiple devices networked together to provide the functionality described herein.

[0051] During the diagnostic process, the DC 302 regulates the overall diagnostic operation of the present system 300. Typically, the DC 302 monitors at least one of the operating parameters or signals of the drive belt 206 for diagnosing the CVT 122 via a network 306 such as a controller area network (CAN) bus. Any type of network having a collection of networkable devices such as computers, servers, and other hardware interconnected by a communication channel is contemplated. Exemplary networks include wired networks or wireless networks or a combination thereof. Exemplary networks may include a Bluetooth-enabled network or a Wi-Fi-enabled network.

[0052] Also included in the diagnostic system 300 are one or more sensors 160 such as a throttle position sensor 308, an engine torque sensor 310, a temperature sensor 312, an engine load sensor 314, a vehicle speed sensor 316, an engine RPM sensor 318, a fuel sensor 320, and the like. Such sensors 160 are operably connected to the DC 302 via a network 306 using a user interface such as a meter 164 or a display 165, and are configured to measure operating characteristics and conditions of the vehicle 100. During operation, information related to operating parameters or signals is displayed on the display 165 accessible to the user via the network 306. It is contemplated that the user may refer to an operator or any other system associated with the diagnostic system 300. The DC 302 manages the interaction between the user and the DC 302 via a human-machine interface (HMI) such as a meter interface, a keyboard, a touch-sensitive pad or screen, a mouse, a trackball, a voice recognition system, and the like. The display 165 (e.g., text and graphics) is configured to receive input data from the user and / or the DC 302.

[0053] In one embodiment, the user interacts with the present system 300 graphically or textually using an input device such as an HMI. Relevant data and / or parameters are typically received in the DC 302 and then transmitted to the display 165 via a dedicated or shared communication system via the network 306. In addition, any collaborative or third-party database accessible to the DC 302 may also be used as part of the diagnostic system 300.

[0054] Now refer to Figure 3 Preferably, DC 302 includes monitoring circuit 322, detection circuit 324, alarm circuit 326, storage circuit 328 and display circuit 330. Although these sub-circuits 322 to 330 are shown as subordinate sub-circuits of parent circuit DC 302, each sub-circuit can be operated as a unit separate from DC, and other suitable combinations of sub-circuits are envisioned to suit different applications. One or more circuits or units can be selectively bundled as a key software model running on a processor with Software as a Service (SSaS) features.

[0055] All relevant information may be stored in a database 304, such as a non-transitory data storage device and / or a machine-readable data storage medium carrying computer-executable instructions, for retrieval by the DC 302 and its subcircuits. Also included in the DC 302 is an interface circuit 332 for providing an interface between the DC 302, the database 304, the network 306, the sensors 160, and the display 165 of the vehicle 100. Preferably, the interface circuit 332 provides electrical interconnections for performing diagnostic operations such as the network 306, the display 165, and other related system devices, services, and applications.

[0056] Other devices, services and applications may include, but are not limited to, one or more software or hardware components associated with DC 302. Interface circuit 332 also receives operational data or parameters associated with vehicle 100 from sensor 160 or other related systems, which are transmitted to corresponding circuits such as DC 302 and its subcircuits.

[0057] The monitoring circuit 322 is configured to receive operating data and parameters via the interface circuit 332 and provide information about operating conditions or characteristics of the vehicle 100. Specifically, the monitoring circuit 322 uses the sensors 160 to provide detailed information about engine or vehicle conditions such as temperature, speed, and power of the vehicle 100 relative to the CVT 122. In general, as discussed in more detail below, the diagnostic system 300 assesses the operating characteristics of the engine or vehicle by evaluating its operating conditions.

[0058] The detection circuit 324 is configured to receive operating data and parameters from the network 306 via the interface circuit 332, and to examine the received operating data and parameters for diagnosing the drive belt 206 based on a predetermined set of rules or algorithms. During operation, the detection circuit 324 recognizes or identifies a predetermined triggering event caused by a change in the condition of the CVT 122, the power source 106, and / or the vehicle 100, and identifies or detects a fault in the drive belt 206 based on the triggering event. Exemplary triggering events are described below with respect to Figures 4 to 7 Described in the paragraph.

[0059] The alarm circuit 326 is configured to generate an information signal or message INFO to notify the user or other users of the detected trigger event by converting the trigger event into a meaningful message recognizable by the user. More specifically, the alarm circuit 326 converts one or more trigger events into a warning signal or status signal of the transmission belt 206. Subsequently, the warning signal or status signal is transmitted to the display 165, the mobile device, or any other computing device to alert the user or other users. It is also contemplated that when a trigger event is detected, the alarm circuit 326 provides an option to override the user input by adjusting one or more values ​​of the operating parameters to prevent damage to the transmission belt 206, thereby mitigating the trigger event. Exemplary information signals are described below with respect to Figures 4 to 7 In one embodiment, a user input is provided to opt out of one or more processing sequences disclosed herein to provide the operator with flexible vehicle performance.

[0060] The storage circuit 328 is configured to digitally store relevant information related to the present diagnostic system 300 in the database 304. More specifically, the database 304 includes operational data and parameters related to analytical data regarding triggering events for the purpose of research, development, improvement of comparative logic or algorithms, and further investigation of users or related systems.

[0061] The display circuit 330 is configured to retrieve from the database 304 and interactively display for illustration on the display 165 appropriate status or information messages associated with the information signals INFO generated based on the triggering events. Example reports related to each information signal INFO and the corresponding triggering event are generated in real time in a graphical or textual manner by the display circuit 330. In one embodiment, the information is automatically transmitted to a central server, other vehicles, or any other suitable system as needed.

[0062] Now refer to Figures 4 to 7 , shows an exemplary processing sequence for executing the present diagnostic system 300. Although the following steps are mainly about Figures 1 to 3 Although the embodiments described above are described in detail, it should be understood that the steps within the processing sequence may be modified and performed in a different order or sequence without changing the principles of the present disclosure.

[0063] Figure 4 An exemplary processing sequence of the belt slip event detection logic 400 of the diagnostic system 300 in the retroactive control mode is shown. The belt slip event is one of the triggering events detected by the detection circuit 324. In the retroactive control mode, when the belt slip event is detected, the alarm circuit 326 has the following options: notify the user of the failure of the drive belt 206, or automatically adjust at least one operating parameter to eliminate or mitigate the impact of the failure on the continued operation of the vehicle 100 without interruption.

[0064] In the illustrated embodiment, steps 402 and 404 are performed simultaneously, but each step may be performed separately or individually independent of each other. In step 402, the monitoring circuit 322 receives a desired vehicle input signal or parameter from a user, such as a predetermined throttle position parameter for opening and closing a throttle control valve from the throttle position sensor 308, or a predetermined engine torque parameter from the engine torque sensor 310.

[0065] In step 404, the monitoring circuit 322 receives an environmental condition parameter or signal from the vehicle 100, such as a temperature signal from a temperature sensor 312 configured to measure the temperature of the drive belt 206 or the air temperature of the CVT 122. For example, the temperature sensor 312 may be disposed in the air supply duct 230 using an infrared sensor, in the air exhaust duct 238, or directly on or near the drive belt 206. Other exemplary environmental condition signals include engine manifold temperature, pressure or vacuum signals, motion signals, crankshaft acceleration signals, transmission gear signals, CVT reduction rate signals, driveline strain or torque signals, steering angle signals, steering rack displacement signals, etc.

[0066] Additional suitable environmental condition signals are also contemplated as needed. For example, in another embodiment, the monitoring circuit 322 can receive a road load condition such as a hard ground condition, a loose sand condition, etc. by using the sensor 160 to detect the road load condition or receiving the road load condition input by the user for applying the road load condition as one of the environmental condition signals.

[0067] Preferably, step 406 and step 408 are performed simultaneously, but each step may be performed separately or individually independent of each other. In step 406, the monitoring circuit 322 receives and monitors at least one engine-based parameter, such as an engine load signal (e.g., %RL) from the engine load sensor 314, a throttle position signal (e.g., throttle position percentage) from the throttle position sensor 308, or an engine torque signal (e.g., inch-pounds or inch-ounces) from the engine torque sensor 310. Other exemplary engine-based parameters include engine power parameters, transmission speed parameters, crankshaft rotation or position parameters, engine control unit (ECU) internal clock parameters, crankshaft acceleration parameters, etc., as received from each corresponding sensor 160.

[0068] In step 408, the monitoring circuit 322 monitors at least one powertrain-based parameter, such as a vehicle speed parameter (e.g., miles per hour) from the vehicle speed sensor 316 or an engine speed parameter (e.g., RPM) from the engine speed sensor 318. Other exemplary powertrain-based parameters include parameters received from infrared sensors, global positioning system sensors, laser sensors, ultrasonic sensors, steering angle sensors, steering rack displacement sensors, gear position sensors, etc. Other suitable chassis-based parameters are also contemplated to suit the application.

[0069] In step 410, the detection circuit 324 detects a belt slip event based on a comparison of at least one of the engine-based parameter and the driveline-based parameter with a predetermined threshold value for preventing damage associated with the drive belt 206 of the CVT 122 or the output driveline of the transmission 130. Any combination of the engine-based parameter and the driveline-based parameter is considered to detect a belt slip event. For example, when the speed ratio between the drive shaft 120 and the driven shaft 128 is 4:1 and the engine load is at 10% to 20% for a predetermined period of time, such as 5 seconds, then a belt slip event is suspected. As another example, when the speed ratio between the drive shaft 120 and the driven shaft 128 is 7:1 and the engine load is at about 50% or greater for a predetermined period of time, such as 1 second, then a belt slip event may be ongoing. When at least one of the engine-based parameter and the driveline-based parameter is greater than the predetermined threshold value, control proceeds to at least one of step 412 and step 414 depending on the application. Otherwise, control returns to step 402 and step 404.

[0070] For example only, a belt slip event F(slip) may be defined by a function of at least one of an engine-based parameter and a powertrain-based parameter and time, as provided by expression (1):

[0071] F(slip)=T·Parm (1)

[0072] Wherein, T represents a time period, and Parm represents at least one of an engine-based parameter and a powertrain-based parameter. As an example, the detection circuit 324 may detect a belt slip event when the engine RPM and powertrain speed parameters exceeding predetermined thresholds continue for a predetermined time period while the vehicle 100 is in a parked or neutral position. An exemplary time period may be in the range of 1 second to 5 seconds.

[0073] Preferably, step 412 and step 414 are performed simultaneously, but each step may be performed separately or individually independent of each other. In step 412, the alarm circuit 326 generates an information signal INFO based on the detected trigger event, the belt slip event, to notify the user of the trigger event using the display 165. For example, the information signal INFO is displayed on the display 165 using a dashboard light or an audible signal including text or a graphical indication (e.g., a symbol or icon). Other suitable audio, visual, or tactile indications are also contemplated.

[0074] In step 414, the alarm circuit 326 automatically adjusts or modifies at least one of the operating parameters such as the expected vehicle input parameter, the environmental condition parameter, the engine-based parameter, or the transmission-based parameter based on the predetermined calibration or empirical lookup table 334 stored in the database 304 to prevent or reduce potential CVT or transmission damage. For example, when the detection circuit 324 identifies a belt slip event, the alarm circuit 326 automatically reduces the engine speed, engine torque, engine load, or throttle position percentage by a predetermined value. Other suitable adjustments or modifications of the operating parameters are contemplated to accommodate different applications. In one embodiment, the automatic adjustment step can be optionally turned on or off as needed, and a progressive warning system can be used to gradually warn the user of potential CVT or transmission damage using color, hue, and saturation intensity techniques. For example, a yellow light can indicate a low-level warning that advises the user to change to a lower gear, while a red light can indicate a high-level warning that automatically reduces the engine load or speed to a predetermined value.

[0075] Figure 5 An exemplary processing sequence of the belt slip event detection logic 500 of the diagnostic system 300 in the proactive control mode is shown. In the proactive control mode, the diagnostic system 300 proactively notifies the user of an impending failure of the drive belt 206 or automatically adjusts at least one of the operating parameters before potential CVT or driveline damage occurs. For example, when the diagnostic system 300 determines that the probability of having a failure is close to about 90%, the alert circuit 326 automatically adjusts at least one operating parameter to eliminate or mitigate the effects of the impending failure of the vehicle 100 without interruption.

[0076] In the illustrated embodiment, preferably, steps 502, 504, and 506 are performed simultaneously, but each step may be performed separately or individually independent of each other. In step 502, the monitoring circuit 322 receives a desired vehicle input signal or parameter from a user. In step 504, the monitoring circuit 322 receives an environmental condition parameter or signal from the vehicle 100. In step 506, the monitoring circuit 322 monitors at least one powertrain-based parameter.

[0077] In step 508, the detection circuit 324 detects a belt slip event based on a comparison of at least one of a user desired vehicle input signal, an environmental condition signal, and a driveline-based parameter with a predetermined threshold value for predicting potential damage associated with the drive belt 206 of the CVT 122 or the output driveline of the transmission 130. Any combination of the user desired vehicle input signal, the environmental condition signal, and the driveline-based parameter is considered to detect a belt slip event. For example, when the desired throttle position percentage is at 20%, the speed ratio between the drive shaft 120 and the driven shaft 128 is 4:1, and the engine load is at 10% to 20% for a predetermined period of time, such as 5 seconds, then a belt slip event may occur. As another example, when the desired throttle position percentage is at 50%, the speed ratio between the drive shaft 120 and the driven shaft 128 is 7:1, and the engine load is at about 50% or greater for a predetermined period of time, such as 1 second, then a belt slip event may be imminent. When the probability of having a failure of drive belt 206 is greater than a predetermined threshold (eg, 90%), control proceeds to at least one of step 510 and step 512 depending on the application. Otherwise, control returns to steps 502, 504, and 506.

[0078] Preferably, steps 510 and 512 are performed simultaneously, but each step may be performed separately or individually independent of the other. In step 510, the alarm circuit 326 generates an information signal INFO based on the detected belt slip event to notify the user of an impending failure of the drive belt 206 before potential belt or drive train damage occurs. Similarly, in step 512, the alarm circuit 326 automatically adjusts or modifies at least one of the operating parameters before the impending failure of the drive belt 206 to prevent or mitigate potential CVT or drive train damage. For example, the alarm circuit 326 automatically reduces the throttle position percentage by a predetermined rate (e.g., 10%, thereby reducing the throttle position percentage from 50% to 40%) to avoid the impending failure of the drive belt 206.

[0079] Figure 6An exemplary processing sequence of the critical belt life event detection logic 600 of the diagnostic system 300 is shown. The critical belt life event is one of the triggering events detected by the detection circuit 324 and is triggered based on a temperature parameter associated with the drive belt 206 of the CVT 122 .

[0080] Based on the temperature parameter received from the temperature sensor 312 configured to measure the temperature of the drive belt 206 or the air temperature of the CVT 122, the detection circuit 324 provides early detection of critical belt life events for avoiding overheating conditions of the drive belt. Therefore, the life and durability of the drive belt 206 can be increased.

[0081] In step 602, the monitoring circuit 322 receives and monitors an ambient condition parameter or signal from the sensor 160, such as a temperature signal from a temperature sensor 312 configured to measure a temperature of a vehicle component such as the drive belt 206 or the intake system 124 or the exhaust system 126 of the CVT 122. For example, the drive belt temperature or the CVT air outlet temperature is measured by one or more temperature sensors 312.

[0082] In step 604, the monitoring circuit 322 receives and monitors at least one engine-based parameter related to an engine load signal, a throttle position signal, an engine torque signal, an engine power signal, etc. Other exemplary engine-based parameters include parameters related to clutch ratio, transmission gear selection or range, intake air pressure, intake air temperature, driveline speed, ECU clock, etc., as received from each corresponding sensor 160.

[0083] In step 606, monitoring circuit 322 receives and monitors at least one powertrain based parameter, such as a vehicle speed parameter from vehicle speed sensor 316 or an engine speed parameter from engine speed sensor 318. In certain embodiments, wheel speed sensors are also used to monitor speed parameters.

[0084] In step 608, the detection circuit 324 detects a critical belt life event based on a comparison of at least one of the engine-based parameter, the powertrain-based parameter, and the ambient condition parameter with a predetermined threshold value to predict the remaining life of the drive belt 206. When at least one of the engine-based parameter, the powertrain-based parameter, and the ambient condition parameter is greater than the predetermined threshold value, control proceeds to at least one of steps 612 and 614. Otherwise, control returns to steps 602, 604, and 606.

[0085] For example only, the critical belt life event F(life) may be defined by a function of time and at least one of an engine-based parameter, a powertrain-based parameter, and an environmental parameter, as provided by expression (2):

[0086] F(life)=Remainer-T·Parm (2)

[0087] Wherein, T represents a time period, Parm represents at least one of an engine-based parameter, a powertrain-based parameter, and an environmental condition parameter, and Remainer represents a remaining life time period left for the drive belt 206. As an example, the detection circuit 324 may detect a critical belt life event when a belt temperature exceeding a predetermined threshold (e.g., greater than 250°F) continues for a predetermined time period (e.g., 10 minutes to 15 minutes) or the remaining life of the drive belt 206 is less than a minimum life threshold. In one embodiment, the minimum life threshold is determined by at least one of the belt temperature, the belt speed, and the belt load. For example only, when the belt temperature is at 250°F for 15 minutes, the remaining life time period is approximately 150 hours, and when the belt temperature is at 330°F for 10 minutes, the remaining life time period is approximately 10 hours. The belt temperature (or belt speed or load) and the belt life time period have an inverse relationship such as a negative exponential slope on a graph. Therefore, the remaining life time period may also be similarly calculated based on the belt speed and the belt load to accommodate different applications. Therefore, the detection circuit 324 predicts thermal degradation of the drive belt 206.

[0088] In step 610, when the detection circuit 324 detects that the remaining life of the drive belt 206 is less than the minimum life threshold (e.g., 10% of the remaining life is left), the control proceeds to at least one of steps 612 and 614 (or both steps 312 and 314) depending on the application. Otherwise, the control returns to steps 602, 604, and 606.

[0089] In step 612, the alarm circuit 326 generates an information signal INFO based on the detected triggering event to notify the user using the display 165. For example, the information signal INFO is displayed on the display 165 by the display circuit 330 using a dashboard light or an audible signal including a textual or graphical indication (e.g., the ℉ / ℃ belt temperature reached (or to be reached), miles to belt failure, percentage of belt life remaining, or percentage of belt life used), requesting maintenance of the drive belt 206. Other suitable audio, visual, or tactile indications are also contemplated.

[0090] In step 614, the alarm circuit 326 automatically adjusts or modifies at least one of the operating parameters, such as the environmental condition parameter, the engine-based parameter, or the driveline-based parameter, based on the calibration table 334 stored in the database 304 to prevent or reduce potential CVT belt failure. For example, when the detection circuit 324 identifies a critical belt life event, the alarm circuit 326 automatically reduces the vehicle speed by a predetermined value. Other suitable adjustments or modifications of the operating parameters are contemplated to accommodate different applications.

[0091] Figure 7 An exemplary processing sequence of the engine crankshaft acceleration change event detection logic 700 of the diagnostic system 300 is shown. The engine crankshaft acceleration change event is one of the triggering events detected by the detection circuit 324 and is triggered based on a change pattern of at least one operating parameter measured during a predetermined time period. It is contemplated to monitor and detect parameter change patterns based on historical information of comparison logic or algorithms.

[0092] During operation, the engine crankshaft acceleration variation event may be considered to be caused by the above-mentioned belt slip event or an improper firing sequence event of the power source 106. The engine crankshaft acceleration variation event detection logic 700 distinguishes the belt slip event from the engine combustion misfire event. Therefore, advantageously, the present method improves the diagnosis of the fault of the drive belt 206 without considering the combustion misfire signal.

[0093] In step 702, the monitoring circuit 322 receives and monitors environmental condition parameters or signals from the vehicle 100, such as a fuel status signal (e.g., fuel on / off) from the fuel sensor 320 or an engine coolant temperature signal from the temperature sensor 312. Other exemplary environmental condition signals include a drive belt temperature signal, a clutch status signal, etc. For example, the clutch status signal may indicate a fully engaged state, a partially engaged state, or a non-engaged state. Moreover, a pulley position signal may be used as one of the environmental condition signals.

[0094] In one embodiment, when the crankshaft acceleration signal is less than a predetermined lower threshold, the belt slip event can be ignored within a predetermined tolerance range. However, when the crankshaft acceleration signal is greater than a predetermined upper threshold (i.e., when the vehicle or engine speed reaches a predetermined threshold), the belt slip event cannot be ignored, and the vehicle 100 is decelerated from the current speed to a lower speed. If the fuel status signal is off during deceleration, the initial predetermined time period may be the optimal time period during which a belt slip event can be detected.

[0095] In step 704, the monitoring circuit 322 receives and monitors at least one engine-based parameter related to the crankshaft acceleration signal, the engine torque signal, the transmission gear signal, etc. Other exemplary engine-based parameters include parameters related to clutch ratio, gear selection or gear, intake pressure, intake temperature, driveline speed, ECU clock, etc. as received from each corresponding sensor 160.

[0096] In step 706, monitoring circuit 322 receives and monitors at least one powertrain based parameter, such as a vehicle speed parameter from vehicle speed sensor 316 or an engine speed parameter from engine speed sensor 318. In one embodiment, wheel speed signals received from wheel speed sensors are also used to monitor speed parameters.

[0097] In step 708, the detection circuit 324 detects an engine crankshaft acceleration change event based on a change pattern of at least one operating parameter measured during a predetermined time period. For example, the engine crankshaft acceleration change event is detected by measuring the acceleration rate or deceleration rate of the crankshaft acceleration signal based on the crankshaft rotation angle (e.g., at each 90°, 180°, or 270°). When the time window acceleration rate or deceleration rate of the crankshaft acceleration signal is greater than a predetermined threshold, the detection circuit 324 identifies the initial detection of the change pattern. In one embodiment, the time window acceleration rate or deceleration rate does not need to be measured throughout the entire cycle of the engine.

[0098] In step 710, after the initial detection of the variation pattern, the detection circuit 324 records or stores data related to the variation pattern in the database 304 at predetermined time intervals (e.g., at each engine cycle time interval) for subsequent comparison. In step 712, when the frequency of the variation pattern is greater than a predetermined threshold, the variation pattern lasts longer than a predetermined period of time, or any combination of the frequency and pattern period is greater than a predetermined threshold (or period of time), control proceeds to at least one of step 714 and step 716. Otherwise, control returns to steps 702, 704, and 706.

[0099] For example only, the engine crankshaft acceleration change event F(ecav) may be defined by a parameter change pattern, a time period (or frequency), and a function of at least one of an engine-based parameter, a driveline-based parameter, and an environmental parameter, as provided by expression (3):

[0100] F(ecav)=Pattern·(T|Freq)·Parm (3)

[0101] Wherein, Pattern represents a parameter change pattern, T represents a time period, Freq represents a frequency of the parameter change pattern, and Parm represents at least one of an engine-based parameter, a transmission-based parameter, and an environmental condition parameter. In one embodiment, the detection circuit 324 detects an engine crankshaft acceleration change event when a predetermined change pattern of the crankshaft acceleration signal is detected, and the detected change pattern lasts for a predetermined time period or is repeated a predetermined number of times. For example, when the engine is in a closed throttle or zero fuel supply event, during a 1 second deceleration time period, the engine may reduce the speed from 3500RPM to 2500RPM. In this case, an undamaged belt will have approximately 100 detectable crankshaft accelerations or decelerations caused by engine compression or inertia. In contrast, a belt with a damaged portion will have approximately 8 to 30 additional detectable crankshaft accelerations or decelerations.

[0102] Preferably, the alarm circuit 326 selectively executes step 714 or step 716 depending on the application. Specifically, in step 714, when a single engine crankshaft acceleration change event is detected, the alarm circuit 326 executes a first correction method or a fast correction method for determining whether the engine crankshaft acceleration change event is caused by a belt slip event or an engine combustion misfire event. In one embodiment, the time window acceleration rate or deceleration rate is determined based on vehicle speed, transmission state, coolant temperature, and clutch state.

[0103] For example only, when an engine crankshaft acceleration change event is detected within a short period of time (e.g., 2 milliseconds to 10 milliseconds) and the fuel state signal is off or the engine speed is low (e.g., 100 RPM), an engine combustion misfire event has not occurred, but a belt slip event is ongoing. In another embodiment, when an engine crankshaft acceleration change event is detected and negative torque is detected, the vehicle 100 decelerates when the torque produced by the engine is less than the torque required for idling. During deceleration, if the drive belt 206 is not fully engaged, a belt slip event may occur. Therefore, it is advantageous to achieve accurate diagnosis of the exact cause of the engine crankshaft acceleration change event through the first correction method or the fast correction method.

[0104] In step 716, when multiple occurrences of engine crankshaft acceleration change events are detected, the alarm circuit 326 performs a second correction method or a slow correction method for determining whether the engine crankshaft acceleration change event is caused by a belt slip event or an engine combustion misfire event. For example, when multiple engine crankshaft acceleration change events are detected during a longer period of time (e.g., 2 seconds to 60 seconds) (optionally, the period of time can be several minutes) and the engine torque is high during the period of time, a belt slip event rather than an engine combustion misfire event is in progress. In one embodiment, a belt slip event is investigated based on identifying one of the fuel shut-off, low torque, and high torque conditions. During the fuel shut-off condition, if there is a change in the crankshaft signal, the engine crankshaft acceleration change event is classified as a belt slip event. During the low torque condition, if the amplitude change of the crankshaft signal is above a certain threshold, the engine crankshaft acceleration change event is classified as a belt slip event. During the high engine torque condition, the engine crankshaft acceleration change event will be classified as an engine combustion misfire event. In one example, if the engine crankshaft acceleration change event cannot be classified as a belt slip event, it is classified as an engine combustion misfire event. In one example, if an engine combustion misfire event is found, the fuel injector of the cylinder that has misfired is disabled. As with the first correction method, it is advantageous to achieve accurate diagnosis of the engine crankshaft acceleration change event through the second correction method or the slow correction method.

[0105] In step 718, the alarm circuit 326 generates an information signal INFO based on the detected trigger event to notify the user using the display 165. For example, the information signal INFO is displayed on the display 165 to warn the user of the occurrence of a belt slip event based on the detected engine crankshaft acceleration change event.

[0106] An example of an engine crankshaft acceleration change event is classified as Figure 8 In the event of belt slip or engine misfire. Figure 8 , providing engine crankshaft acceleration change event detection logic 800.

[0107] As shown in block 810, the monitoring circuit 322 monitors the engine crankshaft position value using input from the engine crankshaft position sensor 802, the engine rpm value using input from the engine rpm sensor 804, and the shiftable transmission input shaft rpm value using input from the downstream rpm sensor 806. The exemplary downstream rpm sensor 806 is positioned to determine the rotational speed of a shaft ultimately driven by the output shaft of the CVT, such as the input shaft of the shiftable transmission, the output shaft of the shiftable transmission, the wheel speed sensor, and the half shaft. If the shaft monitored by the sensor 806 is the output shaft of the shiftable transmission or downstream of the shiftable transmission, a gear position sensor 807 (see Figure 8 ) to indicate the gear ratio of the shiftable transmission. Based on the monitoring value, as shown in block 812, the detection circuit 324 detects a crankshaft acceleration change event. The crankshaft acceleration change event is detected by measuring the acceleration rate or deceleration rate of the crankshaft acceleration signal based on the crankshaft rotation angle (e.g., in increments such as every 1°, 2°, 5°, 10°, 30°, and 90° of rotation), which can be determined based on the engine crankshaft position sensor 802 and the engine rpm sensor 804. Exemplary crankshaft acceleration change events include engine misfire events and CVT damaged belt events, both of which present repeating patterns over time.

[0108] As shown in box 814, the processing sequence 800 determines the interaction frequency that may be associated with a damaged CVT belt. As shown in box 816, the detection circuit 324 monitors the time window acceleration rate or deceleration rate of the observed crankshaft acceleration signal. If an observed crankshaft acceleration change event is detected, the frequency of the observed crankshaft acceleration change event is compared with the determined interaction frequency of the damaged CVT belt by the alarm circuit 326, as shown in box 818. If the observed crankshaft acceleration change event frequency is within a first threshold amount of the determined interaction frequency of the damaged CVT belt, the observed crankshaft acceleration change event is classified as a CVT damaged belt event, as shown in box 820. Otherwise, as shown in box 822, the observed crankshaft acceleration change event is classified as an engine misfire event. In either case, the alarm circuit 326 provides an indication of the condition to the operator of the vehicle. Alternatively, in the case of an engine misfire event, the fuel supplied to the misfired cylinder is stopped, or the fuel and spark supplied to the misfired cylinder are stopped. At the next key press to restart the vehicle, the fuel supply or fuel and spark supply to the cylinders is reset.

[0109] In one embodiment, the first threshold amount is an absolute amount in Hertz, such as 100 Hertz. In another embodiment, the first threshold amount is a percentage amount. An exemplary percentage is within about 10% above or below the determined interaction frequency of the damaged CVT belt. In an embodiment, the observed crankshaft acceleration change event frequency is compared to the determined interaction frequency of the damaged CVT belt and to a multiple of the determined interaction frequency of the damaged CVT belt.

[0110] Reference Fig. 9 , shows an exemplary processing sequence 840 for determining the interaction frequency of a damaged CVT belt. As shown in block 842, the detection circuit 324 detects the engine output speed (E) from the engine rpm sensor 804. 速度 ), and as indicated by block 844, the transmission input speed (T 速度 As shown in block 846, a CVT ratio (CVT Ratio) of the CVT is determined based on the detected engine output speed and the transmission input speed. 比率 ).

[0111] As shown in block 848, based on the determined CVT ratio (CVT 比率 ) and the detected engine output speed (E 速度 ) to determine the pitch diameter (DP) of the transmission clutch 202 of the CVT 200 直径 ). Pitch diameter (DP 直径 ) corresponds to the diameter on the transmission clutch 202 that the drive belt 206 rides on. As is understood in the art, the spacing between the pulley 208 and the pulley 210 is adjustable, resulting in the transmission clutch 202 having many possible pitch diameters. In one example, the diagnostic circuit 302 references the lookup table 850 provided in the database 304 to determine the pitch diameter of the transmission clutch 202. The diagnostic circuit 302 determines the CVT ratio (CVT 比率 ) and the detected engine speed (E 速度 ) is provided as an input to a lookup table 850 which returns a value corresponding to the provided determined CVT ratio (CVT 比率 ) and the detected engine speed (E 速度 ) associated with the pitch diameter (DP 直径 In one example, the diagnostic circuit 302 selects the CVT ratio (CVT) from the lookup table 850 that has the closest corresponding determination. 比率 ) and the detected engine speed (E 速度 ) of the pitch diameter (DP 直径 ).

[0112] As shown in block 852, based on the determined pitch diameter (DP 直径 ), the diagnostic circuit 302 determines the linear belt speed (belt 速度 As shown in block 854, the linear belt speed (belt 速度 ) and the known length of the CVT belt 206 are used by the diagnostic circuit 302 to determine the interaction frequency (belt 频率 If the CVT belt 206 has a damaged region, the damaged region will be at an interaction frequency (band frequency) from block 854 referred to as the damaged CVT belt. 频率 ) interacts with the transmission clutch 202. Exemplary belt damage includes spin burn damage, missing gears on the CVT belt, and rope pop-out.

[0113] Reference Fig.10 , an exemplary processing sequence 900 is shown. The processing sequence 900 adjusts the peak output power of the power source 10 based on a determination that excess energy is accumulating within the CVT 200.

[0114] As indicated at block 902, the diagnostic circuit 302 determines the amount of energy (E 入 As indicated at block 904 , the diagnostic circuit 302 also determines the amount of thermal energy (E ) that leaves the CVT 200 . 出 In one embodiment, the energy input to the CVT 200 is determined based on the mechanical efficiency of the CVT and the mechanical power input to the CVT 200 , while the energy exiting the CVT is determined based on the thermal characteristics of the air flowing through the CVT 200 .

[0115] As indicated at block 906 , the diagnostic circuit 302 calculates the energy (E) entering the CVT 200. 入 ) and the heat energy (E 出 ) is compared to determine whether energy is accumulated in the CVT 200. The energy accumulated in the CVT 200 causes the temperature of the belt 206 of the CVT 200 to increase. 出 ) is less than (E 入 ), energy is accumulated in the CVT 200.

[0116] If energy is accumulated within the CVT 200, the diagnostic circuit 302 compares the amount of accumulated energy to a threshold level, as indicated at block 908. If the amount of accumulated energy exceeds the threshold level, the diagnostic circuit 302 causes the energy (E ) input to the CVT 200 to be reduced, such as by reducing the peak output power of the power source 106 or the peak output torque of the power source 106. 入), as shown in block 910. In one embodiment, the reduction in the peak output power of the power source 106 is gradual to avoid a rapid drop in the peak output power of the power source 106.

[0117] To cause a reduction in the peak output power of the power source 106, the diagnostic circuit 302 sends a message to the ECC 162 of the power source 106. An exemplary message is a CAN message on the CAN network bus. Alternatively, if Figure 3 Diagnostic circuit 302 is shown as being part of ECC 162 , and diagnostic circuit 302 directly limits the peak output power of power source 106 .

[0118] Reference Fig.11 , showing the method for determining the amount of energy (E 入 ) is shown in block 930. As shown in block 932, the diagnostic circuit 302 determines the power source 106, illustratively an internal combustion engine output power level (engine 功率 In one example, the output power level (engine 功率 ) is determined, for example, by multiplying the engine's calculated torque output by the engine speed. Then, as indicated at block 934, the diagnostic circuit 302 retrieves the CVT clutch efficiency (clutch 效率 ).

[0119] CVT clutch efficiency diagram for corresponding output power levels (engine 功率 ) have different efficiency values. In one example, the diagnostic circuit 302 selects the output power level (engine) with the closest corresponding determination from the lookup table 936. 功率 ) of CVT clutch efficiency (clutch 效率 ). CVT clutch efficiency is an estimate of the percentage of energy transferred from the drive shaft 120 associated with the CVT 200 to the driven shaft 128 associated with the CVT 200. It is assumed that the remaining energy is retained as heat inside the CVT 200. As shown in block 938, the diagnostic circuit 302 calculates the engine clutch efficiency from (engine 功率 ) and (1- Clutch 效率 ) to determine the energy (E) input to the CVT 200. 入 ).

[0120] Reference Fig.12 , showing the energy (E) for determining the energy leaving the CVT 200 出). As indicated at block 962, the diagnostic circuit 302 determines the air temperature of the air entering the interior of the CVT 200 via the air supply conduit 230. As indicated at block 964, based on the temperature reading and the heat transfer coefficient 966, the diagnostic circuit 302 determines the amount of energy (E) leaving the CVT 200 based on the CVT clutch airflow model 968. 出 ). The CVT clutch airflow model is based on engine speed (sensor 804), downstream driveline shaft speed (sensor 806), gear position (sensor 807) and the altitude of the vehicle. The altitude of the vehicle can be determined based on the atmospheric pressure measured by the atmospheric pressure sensor or based on the position value provided by the GPS system. In one embodiment, the outlet temperature of the airflow in the exhaust duct 238 is also monitored and used to determine the energy leaving the CVT 200.

[0121] The present disclosure may also be configured as follows:

[0122] Solution 1. A vehicle diagnostic method for a vehicle, the vehicle comprising an internal combustion engine and a continuously variable transmission (CVT) operably coupled to the internal combustion engine, the method comprising the following steps:

[0123] detecting at least one engine crankshaft acceleration change event of the vehicle using a detection circuit;

[0124] determining, using monitoring circuitry, at least one operating parameter received from one or more sensors associated with operation of the CVT; and

[0125] An alert circuit is used to determine when the at least one detected change in engine crankshaft acceleration is associated with a failure of the drive belt of the CVT based on the at least one operating parameter.

[0126] Option 2. The diagnostic method according to Option 1 further includes including an environmental condition parameter as the at least one operating parameter, wherein the environmental condition parameter includes at least one of a fuel state signal, an engine coolant temperature signal, a transmission belt temperature signal, and a clutch state signal.

[0127] Option 3. The diagnostic method according to Option 1 or 2 further includes including an engine-based parameter as the at least one operating parameter, wherein the engine-based parameter is related to at least one of a crankshaft acceleration signal, an engine torque signal and a transmission gear signal.

[0128] Option 4. The diagnostic method according to any one of Options 1 to 3 further includes including a transmission-based parameter as the at least one operating parameter, wherein the transmission-based parameter is related to at least one of a vehicle speed signal, an engine speed signal, and a wheel speed signal.

[0129] Option 5. The diagnostic method according to any one of Options 1 to 4, further comprising detecting the at least one engine crankshaft acceleration change event by measuring an acceleration rate or a deceleration rate of the crankshaft acceleration signal.

[0130] Option 6. The diagnostic method according to any one of options 1 to 5, further comprising detecting the at least one engine crankshaft acceleration change event based on a change pattern of the operating parameter measured during a predetermined time period.

[0131] Option 7. The diagnostic method according to Option 6 further includes determining whether the frequency of the change pattern is greater than a predetermined threshold.

[0132] Option 8. The diagnostic method according to Option 6 or 7 further includes determining whether a pattern time period of the change pattern is greater than a predetermined time period.

[0133] Option 9. The diagnostic method according to any one of Option 6 to Option 8, further comprising determining whether the magnitude of the change pattern.

[0134] Option 10. The diagnostic method according to any one of Options 1 to 9 further includes executing a first correction method, wherein the first correction method is used to determine whether the engine crankshaft acceleration change event is caused by a belt slip event or an engine combustion misfire event based on a single occurrence of the at least one engine crankshaft acceleration change event.

[0135] Option 11. The diagnostic method according to any one of Options 1 to 10 further includes executing a second correction method, wherein the second correction method is used to determine whether the engine crankshaft acceleration change event is caused by a belt slip event or an engine combustion misfire event based on multiple occurrences of the at least one engine crankshaft acceleration change event.

[0136] Embodiment 12. A vehicle diagnostic method for a vehicle, the vehicle comprising an internal combustion engine and a continuously variable transmission (CVT) operably coupled to the internal combustion engine, the method comprising the following steps:

[0137] determining, using monitoring circuitry, at least one operating parameter received from one or more sensors associated with operation of the CVT;

[0138] detecting at least one belt slip event of a drive belt of the CVT using a detection circuit;

[0139] determining, using an alert circuit, when the at least one detected belt slip event is associated with an impending failure of the drive belt of the CVT based on the at least one operating parameter; and

[0140] The warning circuit is used to provide notification of the impending failure of the drive belt before belt or driveline damage to the vehicle occurs.

[0141] Option 13. The diagnostic method according to Option 12 further includes generating an information signal related to the impending failure of the drive belt.

[0142] Option 14. The diagnostic method of Option 12 or Option 13, further comprising providing an option to override user input by adjusting at least one value of the at least one operating parameter.

[0143] Option 15. The diagnostic method according to any one of Option 12 to Option 14, further comprising detecting, by the detection circuit, the at least one belt slip event in at least one of a retroactive control mode and an active control mode.

[0144] Option 16. The diagnostic method of any one of Option 12 to Option 15, further comprising using the monitoring circuit to receive an expected vehicle input parameter.

[0145] Option 17. The diagnostic method according to any one of Options 12 to 16 further includes including an environmental condition parameter as the at least one operating parameter.

[0146] Option 18. The diagnostic method of any one of Option 12 to Option 17, further comprising including an engine-based parameter as the at least one operating parameter.

[0147] Option 19. The diagnostic method according to any one of Options 12 to 18 further includes including a transmission-based parameter as the at least one operating parameter.

[0148] Option 20. The diagnostic method of any one of Option 12 to Option 19, further comprising detecting the belt slip event based on a comparison of engine-based parameters with driveline-based parameters to predict the impending failure of the drive belt.

[0149] Option 21. The diagnostic method according to Option 20 further includes determining whether at least one of the engine-based parameter and the transmission-based parameter is greater than a predetermined threshold.

[0150] Option 22. The diagnostic method according to Option 20 or 21 further includes using a display to notify the at least one detected belt slip event; and automatically adjusting the at least one operating parameter based on a predetermined table.

[0151] Embodiment 23. A vehicle diagnostic method for a vehicle, the vehicle comprising an internal combustion engine and a continuously variable transmission (CVT) operably coupled to the internal combustion engine, the method comprising the following steps:

[0152] determining, using monitoring circuitry, at least one operating parameter received from one or more sensors associated with operation of the CVT;

[0153] detecting at least one critical belt life event of a drive belt of the CVT using a detection circuit;

[0154] determining, using an alert circuit, when the at least one detected critical belt life event is associated with a failure of the drive belt of the CVT based on the at least one operating parameter; and

[0155] The alarm circuit is used to generate an information signal related to the life of the drive belt.

[0156] Option 24. The diagnostic method according to Option 23 further includes including an environmental condition parameter as the at least one operating parameter, wherein the environmental condition parameter includes a temperature signal.

[0157] Option 25. The diagnostic method according to Option 23 or 24 further includes including an engine-based parameter as the at least one operating parameter, wherein the engine-based parameter is related to at least one of an engine load signal, a throttle position signal, an engine torque signal, and an engine power signal.

[0158] Option 26. The diagnostic method according to any one of Options 23 to 25 further includes including a transmission-based parameter as the at least one operating parameter, wherein the transmission-based parameter is related to at least one of a vehicle speed signal and an engine speed signal.

[0159] Option 27. The diagnostic method according to any one of Options 23 to 26 further includes detecting the critical belt life event based on a comparison of engine-based parameters, transmission-based parameters and environmental condition parameters; and predicting the remaining life of the transmission belt based on the comparison.

[0160] Option 28. The diagnostic method according to any one of Option 23 to Option 27, further comprising determining whether the remaining life of the drive belt is less than a predetermined threshold.

[0161] Option 29. The diagnostic method according to Option 27 or 28 further includes displaying the information signal on a display using a text or graphic indication associated with the remaining life of the drive belt.

[0162] Embodiment 30. The diagnostic method of any one of embodiments 23 to 29, further comprising adjusting at least one of an engine-based parameter, a powertrain-based parameter, and an ambient condition parameter based on the at least one detected critical belt life event.

[0163] Embodiment 31. A vehicle diagnostic method for a vehicle, the vehicle comprising an internal combustion engine and a continuously variable transmission (CVT) operably coupled to the internal combustion engine, the method comprising the following steps:

[0164] determining an amount of input energy provided by the internal combustion engine to the CVT;

[0165] determining an amount of output thermal energy exiting the CVT;

[0166] determining an amount of accumulated energy in the CVT based on the amount of input energy and the amount of output thermal energy;

[0167] comparing the amount of accumulated energy to a threshold; and

[0168] The amount of input energy is reduced in response to the amount of accumulated energy satisfying the threshold.

[0169] Option 32. A diagnostic method according to Option 31, wherein the step of reducing the amount of input energy includes the step of reducing the power provided by the internal combustion engine to the CVT.

[0170] Option 33. A diagnostic method according to Option 31 or 32, wherein the amount of input energy is determined based on the mechanical input characteristics of the CVT.

[0171] Option 34. A diagnostic method according to any one of Options 31 to 33, wherein the amount of output thermal energy is determined based on fluid characteristics of the CVT.

[0172] Embodiment 35. The diagnostic method according to any one of embodiments 31 to 34, wherein the step of determining the amount of input energy provided by the internal combustion engine to the CVT comprises the following steps:

[0173] determining a power output of the internal combustion engine;

[0174] determining a CVT clutch efficiency based on the determined output power; and

[0175] An amount of the input energy provided to the CVT is determined based on the determined output power and the determined CVT clutch efficiency.

[0176] Option 36. A diagnostic method according to any one of Options 31 to 35, wherein the step of determining the CVT clutch efficiency based on the determined output power includes the step of retrieving the determined CVT clutch efficiency from a database.

[0177] Embodiment 37. The diagnostic method of any one of embodiments 31 to 36, wherein the step of determining the amount of output thermal energy leaving the CVT comprises the following steps:

[0178] determining an air temperature of air entering an interior of the CVT; and

[0179] The amount of output thermal energy exiting the CVT is determined based on a CVT clutch air flow model, a heat transfer coefficient, and the determined air temperature.

[0180] Embodiment 38. A vehicle diagnostic method for a vehicle, the vehicle comprising an internal combustion engine and a continuously variable transmission (CVT) operably coupled to the internal combustion engine, the method comprising the following steps:

[0181] Detecting multiple engine crankshaft acceleration change events;

[0182] determining a frequency of the plurality of engine crankshaft acceleration change events;

[0183] determining a CVT belt interaction frequency of a drive belt of the CVT; and

[0184] The plurality of engine crankshaft acceleration change events are categorized as one of an engine misfire event and a CVT belt damage event based on a comparison of the frequency to the CVT belt interaction frequency.

[0185] Embodiment 39. The diagnostic method according to any one of embodiments 31 to 38, wherein the step of determining the CVT belt interaction frequency of the drive belt of the CVT comprises the following steps:

[0186] Determining a pitch diameter of a transmission clutch of the CVT;

[0187] determining a linear speed of the drive belt of the CVT based on the determined pitch diameter of the drive clutch and a rotational speed of a drive shaft of the CVT; and

[0188] The CVT belt interaction frequency of the drive belt of the CVT is determined based on the determined linear speed of the drive belt and the length of the belt.

[0189] The above detailed description and the examples described therein are given for the purpose of illustration and description only and are not intended to be limiting. For example, the operations described may be performed in any suitable manner. The method may be performed in any suitable order while still providing the operations and results described. Therefore, it is contemplated that the present embodiment encompasses any and all modifications, variations, or equivalents that fall within the scope of the basic principles disclosed above and claimed herein. In addition, while the above description describes hardware in the form of a processor that executes code, hardware in the form of a state machine, or dedicated logic that can produce the same effect, other structures are also contemplated.

Claims

1. A vehicle diagnostic method for a vehicle, the vehicle comprising an internal combustion engine and a continuously variable transmission operably coupled to the internal combustion engine, the method comprising the following steps: determining, using monitoring circuitry, at least one operating parameter received from one or more sensors associated with operation of the continuously variable transmission; detecting at least one critical belt life event of a drive belt of the continuously variable transmission using a detection circuit; determining, using an alert circuit, based on the at least one operating parameter, when the at least one detected critical belt life event is associated with a failure of the drive belt of the continuously variable transmission; as well as The alarm circuit is used to generate an information signal related to the life of the drive belt.

2. The diagnostic method according to claim 1, wherein: The at least one operating parameter includes an environmental condition parameter including a temperature signal.

3. The diagnostic method according to claim 1, wherein: The at least one operating parameter includes an engine-based parameter related to at least one of an engine load signal, a throttle position signal, an engine torque signal, and an engine power signal.

4. The diagnostic method according to claim 1, wherein: The at least one operating parameter includes a powertrain based parameter related to at least one of a vehicle speed signal and an engine speed signal.

5. The diagnostic method of claim 1 further comprising detecting the critical belt life event based on a comparison of an engine-based parameter, a driveline-based parameter, and an ambient condition parameter; and predicting a remaining life of the drive belt based on the comparison. 6 . The diagnostic method of claim 5 , further comprising determining whether the remaining life of the drive belt is less than a predetermined threshold.

7. The diagnostic method of claim 5 or 6, further comprising displaying the information signal on a display using a textual or graphical indication associated with the remaining life of the drive belt. 8 . The diagnostic method of claim 1 , further comprising adjusting at least one of an engine-based parameter, a powertrain-based parameter, and an ambient condition parameter based on the at least one detected critical belt life event.

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