Vehicle diagnostic methods

Abstract

A vehicle diagnostic method is disclosed. The vehicle includes an internal combustion engine and a continuously variable transmission (CVT) operatively coupled to the internal combustion engine. The method includes the steps of: determining an amount of input energy supplied by the internal combustion engine to the CVT; determining an amount of output heat energy leaving the CVT; determining an 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.

Description

[0001] This application is a divisional application of National Application No. 201880006668.3, International Application Date: January 22, 2018, National Entry Date: July 11, 2019, and Invention Title: "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 January 20, 2017, entitled “DIAGNOSTIC SYSTEMS AND METHODS OF A CONTINUOUSLY VARIABLE TRANSMISSION,” the entire disclosure of which is expressly incorporated herein by reference. Technical Field

[0004] This disclosure generally relates to vehicle diagnostic systems, and more specifically to diagnostic systems for drive belts in continuously variable transmissions (CVTs). Background Technology

[0005] Conventional vehicles, including multi-purpose vehicles and side-by-side vehicles, have internal combustion engines that generate transmission torque. To drive the engine's pistons, an air / fuel mixture is burned in the cylinders, and this mixture is regulated via intake and exhaust valves. The intake valves selectively open to draw air into the cylinders, where it mixes with fuel to form the air / fuel mixture. To allow exhaust gases to escape from the cylinders after combustion, the exhaust valves are selectively opened at specific times.

[0006] Continuously variable transmissions (CVTs) are commonly found in recreational vehicles such as snowmobiles and all-terrain vehicles. A CVT provides numerous different gears that efficiently transmit torque from the engine to the output drivetrain. The output drivetrain operatively engages the transmission with at least one ground-mounted component.

[0007] However, due to the belt structure of a CVT, one of its drawbacks is that the CVT drive belt tends to wear and become prematurely damaged when it is not properly maintained or overused under undesirable conditions. Because the drive belt only transmits engine power from the CVT's drive pulley to the driven pulley, it is a critical component of the CVT. Typically, CVT drive belts are V-belts made of rubber, usually fiber-reinforced, and are rigid yet flexible along their length. During operation, the drive belt is subjected to significant pressure and friction.

[0008] When the drive belt loses pressure between the pulleys of a CVT under high load or overload conditions, slippage can occur, leading to belt damage such as rotational combustion or hour-glassing events. For example, during a rotational combustion event, the belt temperature can rapidly reach over 200 degrees Fahrenheit (℉) without any warning, and can continue to rise to 400℉ without remedial action. At that point, the drive belt is irreparably damaged, and the vehicle becomes inoperable without replacing the damaged belt, resulting in 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 drive belt failures before potential belt damage occurs. Summary of the Invention

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

[0011] This disclosure also includes systems and methods configured to monitor changes in operating parameters over a predetermined time period based on historical information from comparison logic or algorithms. Furthermore, this diagnostic system provides enhanced real-time display of the relationships between operating parameters. Moreover, operating parameters are automatically displayed without significant manual interruptions. Therefore, the overall operating time of the engine system is improved without incurring additional operating costs and maintenance expenses.

[0012] In one exemplary embodiment, a vehicle diagnostic method is provided for a vehicle including an internal combustion engine and a continuously variable transmission (CVT) operatively coupled to the internal combustion engine. The method includes the steps of: using detection circuitry to detect at least one engine crankshaft acceleration change event of the vehicle; using monitoring circuitry to determine at least one operating parameter received from one or more sensors associated with the operation of the CVT; and using alarm circuitry to determine, based on the at least one operating parameter, when the at least one detected engine crankshaft acceleration change is related to a fault in the CVT's drive belt. In one example, the diagnostic method further includes including an environmental condition parameter as at least one operating parameter, wherein the environmental condition parameter includes at least one of a fuel status signal, an engine coolant temperature signal, a drive belt temperature signal, and a clutch status signal. In another example, the diagnostic method further 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 position signal. In yet another example, the diagnostic method further includes including a drivetrain-based parameter as at least one operating parameter, wherein the drivetrain-based parameter is related to at least one of a vehicle speed signal, an engine speed signal, and wheel speed signals. In yet another example, the diagnostic method further includes detecting at least one engine crankshaft acceleration change event by measuring the acceleration or 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 operating parameters measured over 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 magnitude of the change pattern is significant. In yet another example, the diagnostic method further includes performing a first correction method for determining whether the engine crankshaft acceleration change event is caused by a slippage event or an engine 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 performing a second correction method for determining whether the engine crankshaft acceleration change event is caused by a slippage event or an engine misfire event based on multiple occurrences of at least one engine crankshaft acceleration change event.

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

[0014] In another exemplary embodiment, a vehicle diagnostic method is provided for a vehicle including an internal combustion engine and a continuously variable transmission (CVT) operatively coupled to the internal combustion engine. The method includes the steps of: using monitoring circuitry to determine at least one operating parameter received from one or more sensors associated with the operation of the CVT; using detection circuitry to detect at least one critical belt life event of the CVT's drive belt; using alarm circuitry to determine, based on the at least one operating parameter, when the at least one detected critical belt life event is related to a failure of the CVT's drive belt; and using alarm circuitry to generate an information signal related to the life of the drive belt. In the example, the diagnostic method further 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 further 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 further includes including a drivetrain-based parameter as at least one operating parameter, wherein the drivetrain-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 comparisons of engine-based parameters, drivetrain-based parameters, and environmental condition parameters; and predicting the remaining life of the drive belt based on these comparisons. In a variation, the diagnostic method further includes determining whether the remaining life of the drive belt is less than a predetermined threshold. In another variation, the diagnostic method further includes displaying an information signal on a display using text or graphic indicators associated with the remaining life of the drive belt. In yet another example, the diagnostic method further includes adjusting at least one of the engine-based parameters, drivetrain-based parameters, and environmental condition parameters based on at least one detected critical belt life event.

[0015] In another exemplary embodiment of this disclosure, a vehicle diagnostic method is provided for a vehicle including an internal combustion engine and a continuously variable transmission (CVT) operatively coupled to the internal combustion engine. The method includes the steps of: determining an amount of input energy supplied by the internal combustion engine to the CVT; determining an amount of output heat energy leaving the CVT; determining an 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 to a threshold; and reducing the amount of input energy in response to the amount of accumulated energy satisfying the threshold. In one example, the step of reducing the amount of input energy includes reducing the power supplied 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 supplied by the internal combustion engine to the CVT includes the steps of: 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 supplied to the CVT based on the determined output power and the determined CVT clutch efficiency. In a variation, the step of determining the CVT clutch efficiency based on a given output power includes 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 following steps: determining the air temperature of the air entering the CVT; and determining the amount of output heat energy leaving the CVT based on the CVT clutch airflow model, the heat transfer coefficient, and the determined air temperature.

[0016] In another exemplary embodiment of this disclosure, a vehicle diagnostic method is provided for a vehicle including an internal combustion engine and a continuously variable transmission (CVT) operatively coupled to the internal combustion engine. The method includes the steps of: detecting a plurality of engine crankshaft acceleration variation events; determining the frequency of the plurality of engine crankshaft acceleration variation events; determining the CVT belt interaction frequency of the CVT's drive belt; and classifying the plurality of engine crankshaft acceleration variation events into one of an engine misfire event and a CVT belt failure event based on a comparison of the frequency and the CVT belt interaction frequency. In an example thereon, the step of determining the CVT belt interaction frequency includes the steps of: determining the pitch circle diameter of the CVT's drive clutch; determining the linear velocity of the CVT's drive belt based on the determined pitch circle diameter of the drive clutch and the rotational speed of the CVT's drive shaft; and determining the CVT belt interaction frequency based on the determined linear velocity of the CVT's drive belt and the belt length.

[0017] In yet another exemplary embodiment of this disclosure, a diagnostic system for diagnosing the drive belt of a continuously variable transmission (CVT) is provided. The diagnostic circuitry detects or predicts drive belt failures based on operating parameters received from sensors associated with the vehicle during a predetermined diagnostic period.

[0018] Additional features and advantages of this disclosure will become apparent to those skilled in the art when considering the following detailed description of exemplary embodiments, which exemplify the best mode of carrying out the invention as currently recognized. Attached Figure Description

[0019] The embodiments will be more readily understood in conjunction with the following description taken in conjunction with the accompanying drawings, wherein similar reference numerals denote similar elements, wherein:

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

[0021] Figure 2 A representative diagram of the initial airflow of an exemplary continuously variable transmission (CVT) is shown;

[0022] Figure 3 An exemplary block diagram and schematic diagram of an illustrative embodiment of a diagnostic system having engine control circuitry and diagnostic circuitry are shown.

[0023] Figure 4 An exemplary processing sequence for executing this diagnostic system to detect slippage events in traceability control mode is shown;

[0024] Figure 5 An exemplary processing sequence for performing this diagnostic system to detect slippage events in look-ahead control mode is shown;

[0025] Figure 6 An exemplary processing sequence for performing this diagnostic system to detect critical band lifetime events is shown;

[0026] Figure 7 An exemplary processing sequence for performing this diagnostic system to detect engine misfire events is shown;

[0027] Figure 8 An exemplary processing sequence of this diagnostic system with events is shown for detecting engine misfire events or damage;

[0028] Figure 9 An exemplary processing sequence for determining the interaction frequency of CVT strips is shown;

[0029] Figure 10 An exemplary processing sequence is shown to adjust the peak output power of the power source based on the accumulated energy in the CVT;

[0030] Figure 11 An exemplary processing sequence for determining the amount of energy input to the CVT during CVT operation is shown; and

[0031] Figure 12 An exemplary processing sequence is shown for determining the amount of energy leaving the CVT during CVT operation.

[0032] Throughout these figures, corresponding reference numerals indicate the corresponding parts. Although the figures illustrate embodiments of this disclosure, they are not necessarily drawn to scale, and some features may be exaggerated to better illustrate and explain this disclosure. The examples set forth herein illustrate exemplary embodiments of this disclosure in one form, and such examples should not be construed as limiting the scope of this disclosure in any way. Detailed Implementation

[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 were chosen and described to enable others skilled in the art to utilize their teachings. While this disclosure relates primarily to continuously variable transmissions (“CVTs”), 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, multi-purpose vehicles, motorcycles, snowmobiles, golf carts, and other vehicles or devices incorporating CVTs.

[0034] Now refer to Figure 1 A representative diagram of vehicle 100 is shown. Vehicle 100, as shown, includes multiple ground engagement components 102. Illustratively, ground engagement component 102 is a wheel 104 with associated tires. Other exemplary ground engagement components include skis and tracks. In one embodiment, one or more wheels may be replaced by tracks, such as the Explorer II track available from Polaris Industries, located at 2100 Highway 55, Medina, Minnesota 55340.

[0035] One or more of the ground engagement members 102 are operatively coupled to a shiftable transmission 130 for powering the movement of the vehicle 100. Other suitable types of transmissions, such as non-shiftable gear sets, are also contemplated. An exemplary power source 106 includes an internal combustion engine and an electric motor. In the illustrated embodiment, the power source 106 is an internal combustion engine.

[0036] Internal combustion power source 106 Figure 1As shown. Power source 106 receives fuel from fuel source 108 and ambient air from intake system 110. For example, ambient air is selectively supplied to power source 106 to mix with fuel for internal combustion. Exhaust is discharged from power source 106 through exhaust system 112. Output shaft 120 of power source 106 is coupled to the drive member of continuously variable transmission (“CVT unit”) 122. Driven member of CVT unit 122 is operatively coupled to the drive member of CVT unit 122 via a drive belt. CVT unit 122 receives ambient air through intake system 124 and exhausts air from inside CVT unit 122 through exhaust system 126. Driven member is coupled to output shaft 128, which is operatively coupled to the input of shiftable transmission 130.

[0037] The first output shaft 132 of the shiftable transmission 130 is connected to the rear drive unit 134. The rear drive unit 134 is connected to the corresponding wheels 104 of the 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 connected to the front drive unit 142. The front drive unit 142 is connected to the corresponding wheels 104 of the 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 envisioned. Regarding the rear drive unit 134, in one embodiment, the rear drive unit 134 is a locked differential, wherein power is supplied to the two wheels of axle 136 via output shaft 150. In another embodiment, the rear drive unit 134 is a lockable / unlockable differential relative to output shaft 150. When the rear drive unit 134 is in the locked configuration, power is supplied to the two wheels of axle 136 via output shaft 150. When the rear drive unit 134 is in the unlocked configuration, power is supplied to one of the wheels of axle 136 via output shaft 150, such as a wheel with less resistance relative to the ground. Regarding the front drive unit 142, in one embodiment, the front drive unit 142 has: a first configuration, wherein power is supplied to the two wheels of the front axle 144; and a second configuration, wherein power is supplied to one of the wheels of axle 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”). The 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 two-wheel drive systems to suit this application. Exemplary front drive units are disclosed in U.S. Patent Application Serial No. 12 / 816,052, U.S. Patent No. 5,036,939, and U.S. Patent RE38,012E, filed June 15, 2010, entitled “ELECTRIC VEHICLE”, the disclosures of which are expressly incorporated herein by reference.

[0040] In one embodiment, one or more of the CVT unit 122, intake system 124, and exhaust system 126 include sensors 160 that monitor the characteristics of the air inside the respective CVT unit 122, intake system 124, and exhaust system 126. In the illustrated embodiment, multiple sensors 160 are operatively and communicatively connected to the transmission 130, wheels 104, intake system 124, exhaust system 126, and CVT unit 122 to receive signals from at least one of the connected sensors. Exemplary sensors include temperature sensors, speed sensors, and load sensors. In one embodiment, sensor 160 provides an indication of the temperature of the air inside the respective CVT unit 122, intake system 124, and exhaust system 126 to an engine control circuit (ECC) 162 that includes logic controlling the operation of the power source 106. When the detected air temperature exceeds a threshold amount, ECC162 responds to the operator of vehicle 100 via a user interface such as instrument cluster 164 or display 165 within the operator area of ​​vehicle 100 by limiting the output speed of the output shaft 120 of power source 106, limiting the speed of vehicle 100, and indicating an overheating condition. An exemplary user interface is disclosed in U.S. Patent Application No. 15 / 161,720, filed May 23, 2016, entitled “DISPLAY SYSTEMS AND METHODS FOR A RECREATIONAL VEHICLE,” file number PLR-12-27457-01P-US-E, the entire disclosure of which is expressly incorporated herein by reference. Exemplary indications of an overheating condition include lights, warning messages on display 165, and other suitable means of communicating the condition to the operator. By limiting engine speed or vehicle speed, the temperature of the air inside CVT unit 122 is reduced, and the temperature of the drive belt inside CVT unit 122 is also reduced. This reduces the risk of drive belt failure.

[0041] Reference Figure 2 An exemplary continuously variable transmission (CVT) 200 is shown. The CVT 200 includes a drive clutch 202 operably coupled to an output shaft 120, a driven clutch 204 operably coupled to an output shaft 128, and a drive belt 206 operably coupled to the drive clutch 202 and the driven clutch 204 to transmit power from the drive clutch 202 to the driven clutch 204. The drive clutch 202 includes a first drive clutch pulley 208 and a second drive clutch pulley 210 movable relative to the first drive 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 drive clutch 202 and the driven clutch 204 are positioned within a housing 220 having an interior 222. The housing 220 may include a plurality of components that mate to form the housing 220. These components may also include features that direct airflow 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 a drive shaft 120 and a second opening adapted to receive a driven shaft 128. The cover and the base mate to define the interior 222 of the housing 220. The cover and the base may include features that direct airflow through the interior 222 of the housing 220.

[0043] like Figure 2 As shown, one or more air supply ducts 230 are connected to the housing 220. Exemplary air supply ducts include flexible hoses. In one embodiment, each air supply duct 230 supplies 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 ducts 230 supply air to the interior 222 of the housing 220 to cool the drive clutch 202, the driven clutch 204, and the drive belt 206. Therefore, this configuration provides a cooling effect on the drive belt 206. The supplied air is directed toward 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, wherein the supplied air absorbs heat to cool one or more of the corresponding first drive clutch pulley 208, second drive clutch pulley 210, first driven clutch pulley 212, and second driven clutch pulley 214. Air then circulates within the interior 222 of 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 exits the interior 222 of housing 220 through one or more air exhaust openings 236 in the wall 234 of housing 220. One or more exhaust or outlet pipes 238 are connected 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 with a diagnostic circuit (DC) 302. The DC 302 is configured to detect or predict faults in the drive belt 206 of the CVT 122 based on at least one operating parameter such as engine or vehicle parameters or signals. Although the DC 302 is shown inside the ECC, the DC can be independent of the ECC or separate from the ECC, or integrated into any other system of the vehicle 100 to suit the application.

[0045] A failure of the drive belt 206 can refer to a deterioration of the drive belt caused by rotational combustion or a timing hourglass event. For example, slippage in the drive belt 206 during substantial rotation of the drive pulley relative to the near-stationary drive belt can produce a timing hourglass event that alters the side profile of the drive belt 206 to the shape of a timing hourglass. As an example only, when the wheel 104 is stuck in a ditch such as mud or snow or loose soil, the engine speed may increase, but the wheel speed may decrease to almost zero. This insufficient rotational movement 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, DC 302 is microprocessor-based and includes a non-transitory computer-readable medium or database 304, which includes processing instructions stored therein that can be executed by the microprocessor of DC 302 to control the diagnostic process of CVT 122. The non-transitory computer-readable medium or memory may include random access memory (RAM), read-only memory (ROM), 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 experience lookup table may be stored on volatile or non-volatile memory for subsequent access.

[0047] Exemplary operating parameters include engine speed (e.g., revolutions per minute (RPM)), engine load (e.g., percentage of relative load in units of %RL)), throttle position (e.g., throttle position percentage), engine torque (e.g., inch-pound or inch-ounce), engine power, etc. Other suitable operating parameters are also envisioned to suit different applications. The following section discusses... Figures 4 to 7 The relevant paragraphs provide detailed descriptions of exemplary operating parameters and signals.

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

[0049] As used herein, the term "logic" includes software and / or firmware that execute on one or more circuits. Therefore, various logics can be implemented in any suitable manner, depending on the implementation, and will remain in accordance with the implementation disclosed herein. A non-transitory machine-readable medium including logic can also be considered to be embodied in any tangible form of a computer-readable carrier such as solid-state memory, a magnetic disk, and an optical disk, containing a set of appropriate computer instructions and data structures that will enable a processor to perform the techniques described herein.

[0050] This disclosure envisions alternative implementations where DC 302 is not microprocessor-based, but rather configured to regulate the operation of the diagnostic process of CVT 122 based on one or more sets of hardwired instructions and / or software instructions stored in database 304. Furthermore, 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, DC 302 regulates the overall diagnostic operation of the system 300. Typically, DC 302 monitors at least one of the operating parameters or signals of the drive belt 206 used for diagnosing the CVT 122 via a network 306 such as a Controller Area Network (CAN) bus. Any type of network is envisioned, comprising a collection of networkable devices such as computers, servers, and other hardware interconnected via communication channels. Exemplary networks include wired or wireless networks, or combinations thereof. Exemplary networks may include Bluetooth-enabled networks or Wi-Fi-enabled networks.

[0052] The diagnostic system 300 also includes 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, etc. These sensors 160 are operably connected to the DC 302 via a network 306 using a user interface such as an instrument cluster 164 or a display 165, and are configured to measure the operating characteristics and conditions of the vehicle 100. During operation, relevant information about operating parameters or signals is displayed on the display 165, which is accessible to the user via the network 306. It is envisioned that the user can refer to the 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 an instrument cluster interface, keyboard, touchpad or screen, mouse, trackball, voice recognition system, etc. 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 implementation, the user interacts with the system 300 graphically or text-based 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 through the network 306. Furthermore, any collaborative or third-party databases accessible from the DC 302 can also be used as part of the diagnostic system 300.

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

[0055] All relevant information can be stored in a database 304 for retrieval by the DC 302 and its sub-circuits, for example, as a non-transitory data storage device and / or a machine-readable data storage medium carrying computer-executable instructions. The DC 302 also includes interface circuitry 332 for providing an interface between the DC 302, database 304, network 306, sensor 160, and display 165 of the vehicle 100. Preferably, the interface circuitry 332 provides electrical interconnections for performing diagnostic operations, such as those of the network 306, 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 related to vehicle 100 from sensor 160 or other relevant systems, which are transmitted to appropriate circuits such as DC 302 and its sub-circuits.

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

[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 identifies or recognizes predetermined trigger events caused by changes in the condition of the CVT 122, the power source 106, and / or the vehicle 100, and identifies or detects faults in the drive belt 206 based on these trigger events. Exemplary trigger events are described below regarding... Figures 4 to 7 Described in the paragraph.

[0059] Alarm circuit 326 is configured to generate an information signal or message INFO to notify the user or other users of detected trigger events by converting trigger events into meaningful messages that are recognizable to the user. More specifically, alarm circuit 326 converts one or more trigger events into warning signals or status signals for the drive belt 206. The warning signals or status signals are then transmitted to display 165, mobile device, or any other computing device to alert the user or other users. It is also envisioned that, upon detecting a trigger event, alarm circuit 326 provides an option to override user input by adjusting one or more values ​​of operating parameters to prevent damage to the drive belt 206, thereby mitigating the trigger event. Exemplary information signals are described below regarding... Figures 4 to 7 As described in the paragraphs. In one implementation, user input is provided to select to exit one or more processing sequences disclosed herein, providing the operator with flexible vehicle performance.

[0060] Storage circuitry 328 is configured to digitally store relevant information relating to the diagnostic system 300 in database 304. More specifically, database 304 includes operational data and parameters related to analytical data concerning triggering events, for the purposes of comparative logic or algorithm research, development, improvement, and further investigation of the user or related systems.

[0061] Display circuitry 330 is configured to retrieve from database 304 and interactively display on display 165 the appropriate status or information message associated with an information signal INFO generated based on a trigger event. Instance reports associated with each information signal INFO and its corresponding trigger event are generated in real-time by display circuitry 330 in graphical or textual form. In one embodiment, 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 This illustrates an exemplary processing sequence for performing this diagnostic system 300. Although the following steps are primarily about... Figures 1 to 3 As described in the embodiments, it should be understood that the steps within the processing sequence can be modified and executed in a different order or sequence without changing the principles of this disclosure.

[0063] Figure 4 An exemplary processing sequence of the belt slippage event detection logic 400 of the diagnostic system 300 in trace control mode is shown. A belt slippage event is one of the trigger events detected by the detection circuit 324. In trace control mode, when a belt slippage event is detected, the alarm circuit 326 has the option to: notify the user of a fault in the drive belt 206, or automatically adjust at least one operating parameter to eliminate or mitigate the impact of the fault on the continuous 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 independently or separately. In step 402, the monitoring circuit 322 receives desired vehicle input signals or parameters from the user, such as predetermined throttle position parameters for opening and closing the throttle control valve from the throttle position sensor 308, or predetermined engine torque parameters from the engine torque sensor 310.

[0065] In step 404, monitoring circuit 322 receives environmental condition parameters or signals from vehicle 100, such as temperature signals from temperature sensor 312 configured to measure the temperature of drive belt 206 or the air temperature of CVT 122. For example, temperature sensor 312 may be an infrared sensor located in air supply duct 230, air exhaust duct 238, or directly on or near 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, drivetrain strain or torque signals, steering angle signals, steering rack displacement signals, etc.

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

[0067] Preferably, steps 406 and 408 are performed simultaneously, but each step may be performed independently or separately. In step 406, monitoring circuit 322 receives and monitors at least one engine-based parameter, such as an engine load signal (e.g., %RL) from engine load sensor 314, a throttle position signal (e.g., throttle position percentage) from throttle position sensor 308, or an engine torque signal (e.g., inch-pound or inch-ounce) from 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., received from each corresponding sensor 160.

[0068] In step 408, monitoring circuitry 322 monitors at least one drivetrain-based parameter, such as a vehicle speed parameter (e.g., mph) from vehicle speed sensor 316 or an engine speed parameter (e.g., RPM) from engine speed sensor 318. Other exemplary drivetrain-based parameters include parameters received from infrared sensors, GPS sensors, laser sensors, ultrasonic sensors, steering angle sensors, steering rack displacement sensors, gear position sensors, etc. Other suitable chassis-based parameters are also envisioned to suit this application.

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

[0070] For illustrative purposes only, the slip event F(slip) can be defined as a function of at least one of the engine-based parameters and the transmission-based parameters, and time, as provided by expression (1):

[0071] F(slip) = T·Parm (1)

[0072] Where T represents a time period, and Parm represents at least one of the engine-based parameters and the transmission-based parameters. As an example, when the engine RPM and transmission speed parameters exceed a predetermined threshold for a predetermined time period while the vehicle 100 is in a parked or neutral position, the detection circuit 324 can detect a slippage event. An exemplary time period can be in the range of 1 to 5 seconds.

[0073] Preferably, steps 412 and 414 are performed simultaneously, but each step may be performed independently or separately. In step 412, alarm circuit 326 generates an information signal INFO based on the detected trigger event, including a slippage event, to notify the user of the trigger event using display 165. For example, the information signal INFO may be displayed on display 165 using dashboard lights or audible signals including text or graphic indicators (e.g., symbols or icons). Other suitable audio, visual, or tactile indicators are also envisioned.

[0074] In step 414, the alarm circuit 326 automatically adjusts or modifies at least one of the following operating parameters—such as desired vehicle input parameters, environmental condition parameters, engine-based parameters, or transmission-based parameters—based on a predetermined calibration or experience 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 slippage event, the alarm circuit 326 automatically reduces engine speed, engine torque, engine load, or throttle position percentage by a predetermined value. Other suitable adjustments or modifications to operating parameters are envisioned to suit 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 suggesting the user shift to a lower gear, while a red light can indicate a high-level warning to automatically reduce engine load or speed to a predetermined value.

[0075] Figure 5 An exemplary processing sequence of the belt slippage event detection logic 500 of the diagnostic system 300 in look-ahead control mode is shown. In look-ahead 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 a potential CVT or drivetrain failure occurs. For example, when the diagnostic system 300 determines that the probability of a failure is close to approximately 90%, the alarm 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, steps 502, 504, and 506 are preferably performed simultaneously; however, each step may be performed independently or separately. In step 502, monitoring circuit 322 receives desired vehicle input signals or parameters from the user. In step 504, monitoring circuit 322 receives environmental condition parameters or signals from vehicle 100. In step 506, monitoring circuit 322 monitors at least one transmission system-based parameter.

[0077] In step 508, the detection circuit 324 detects a belt slippage event by comparing at least one of the user-expected vehicle input signal, environmental condition signal, and drivetrain-based parameters with a predetermined threshold used to predict potential damage to the output drivetrain of the CVT 122's drive belt 206 or the transmission 130. Any combination of the user-expected vehicle input signal, environmental condition signal, and drivetrain-based parameters is considered to detect a belt slippage event. For example, a belt slippage event may occur when the expected throttle position percentage is 20%, the speed ratio between driveshaft 120 and driven shaft 128 is 4:1, and the engine load is between 10% and 20% for a predetermined time period of, for example, 5 seconds. As another example, a belt slippage event may be imminent when the expected throttle position percentage is 50%, the speed ratio between driveshaft 120 and driven shaft 128 is 7:1, and the engine load is approximately 50% or greater for a predetermined time period of, for example, 1 second. When the probability of a failure in drive belt 206 is greater than a predetermined threshold (e.g., 90%), control depends on the application to proceed to at least one of steps 510 and 512. Otherwise, control returns to steps 502, 504, and 506.

[0078] Preferably, steps 510 and 512 are performed simultaneously, but each step can be performed independently or separately. In step 510, alarm circuit 326 generates an information signal INFO based on a detected belt slippage event to notify the user of an impending failure of drive belt 206 before potential belt or drivetrain damage occurs. Similarly, in step 512, alarm circuit 326 automatically adjusts or modifies at least one of the operating parameters before the impending failure of drive belt 206 to prevent or mitigate potential CVT or drivetrain damage. For example, 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 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 temperature parameters related to the drive belt 206 of the CVT 122.

[0080] Based on temperature parameters received from temperature sensor 312, which is configured to measure the temperature of the drive belt 206 or the air temperature of the CVT 122, detection circuit 324 provides earlier detection of critical belt life events to prevent overheating of the drive belt. Therefore, the lifespan and durability of the drive belt 206 can be increased.

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

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

[0083] In step 606, monitoring circuit 322 receives and monitors at least one drivetrain-based parameter, such as a vehicle speed parameter from vehicle speed sensor 316 or an engine speed parameter from engine speed sensor 318. In some 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 engine-based parameters, drivetrain-based parameters, and environmental condition parameters with a predetermined threshold, to predict the remaining life of the drive belt 206. When at least one of the engine-based parameters, drivetrain-based parameters, and environmental condition parameters is greater than the predetermined threshold, control proceeds to at least one of steps 612 and 614. Otherwise, control returns to steps 602, 604, and 606.

[0085] For illustrative purposes only, the critical band life event F(life) can be defined as a function of time and at least one of the following: engine-based parameters, transmission-based parameters, and environmental parameters, as provided by expression (2):

[0086] F(life)=Remainer-T·Parm (2)

[0087] Where T represents a time period, Parm represents at least one of parameters based on the engine, parameters based on the drivetrain, and environmental conditions, and Remainer represents the remaining lifespan of the drive belt 206. As an example, the detection circuit 324 can detect a critical belt lifespan event when the belt temperature exceeds a predetermined threshold (e.g., greater than 250℉) for a predetermined time period (e.g., 10 to 15 minutes) or when the remaining lifespan of the drive belt 206 is less than a minimum lifespan threshold. In one embodiment, the minimum lifespan threshold is determined by at least one of belt temperature, belt speed, and belt load. As an example only, when the belt temperature is 250℉ for 15 minutes, the remaining lifespan is approximately 150 hours, while when the belt temperature is 330℉ for 10 minutes, the remaining lifespan is approximately 10 hours. Belt temperature (or belt speed or load) and belt lifespan have an inverse relationship, such as a negative exponential slope on a graph. Therefore, the remaining lifespan can also be calculated similarly based on belt speed and belt load to suit different applications. Thus, 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 lifespan of the drive belt 206 is less than the minimum lifespan threshold (e.g., leaving 10% of the remaining lifespan), control depends on the application to proceed to at least one of steps 612 and 614 (or simultaneously to steps 312 and 314). Otherwise, control returns to steps 602, 604, and 606.

[0089] In step 612, alarm circuit 326 generates an information signal INFO based on the detected trigger event to notify the user using display 165. For example, the information signal INFO is displayed on display 165 by display circuit 330 using dashboard lights or audible signals that include text or graphic indications (e.g., reached (or to be reached) °C belt temperature, miles with fault, percentage of remaining life with belt, or percentage of life used with belt), requesting maintenance of drive belt 206. Other suitable audio, visual, or tactile indications are also envisioned.

[0090] In step 614, the alarm circuit 326 automatically adjusts or modifies at least one of the operating parameters, such as environmental condition parameters, engine-based parameters, or transmission system-based parameters, based on calibration table 334 stored in database 304, to prevent or reduce potential CVT drive belt failures. 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 to the operating parameters are envisioned to suit 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 trigger 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. Monitoring and detection of parameter change patterns based on historical information from comparison logic or algorithms is envisioned.

[0092] During operation, engine crankshaft acceleration variation events can be attributed to either the aforementioned belt slippage event or an incorrect ignition sequence event of power source 106. Engine crankshaft acceleration variation event detection logic 700 distinguishes between belt slippage events and engine misfire events. Therefore, advantageously, this method improves the diagnosis of faults in drive belt 206 without considering misfire signals.

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

[0094] In one implementation, when the crankshaft acceleration signal is less than a predetermined lower threshold, the slippage 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 slippage event cannot be ignored, and the vehicle 100 is decelerated from its current speed to a lower speed. If the fuel status signal is off during deceleration, the initial predetermined time period can be the optimal time period for detecting the slippage event.

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

[0096] In step 706, monitoring circuit 322 receives and monitors at least one drivetrain-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 engine crankshaft acceleration change events based on a change pattern of at least one operating parameter measured during a predetermined time period. For example, engine crankshaft acceleration change events are detected by measuring the rate of acceleration or deceleration of the crankshaft acceleration signal based on crankshaft rotation angles (e.g., at each 90°, 180°, or 270°). When the time window acceleration or deceleration rate of the crankshaft acceleration signal exceeds a predetermined threshold, the detection circuit 324 identifies the initial detection of the change pattern. In one embodiment, it is not necessary to measure the time window acceleration or deceleration rate throughout the entire engine cycle.

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

[0099] For illustrative purposes only, the engine crankshaft acceleration variation event F(ecav) can be defined as a function of the parameter variation pattern, time period (or frequency), and at least one of the following: engine-based parameters, transmission-based parameters, and environmental parameters, as provided by expression (3):

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

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

[0102] Preferably, the alarm circuit 326 selectively executes either 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 rapid correction method to determine whether the engine crankshaft acceleration change event is caused by a slippage event or an engine misfire event. In one embodiment, the acceleration or deceleration rate within a time window is determined based on vehicle speed, transmission status, coolant temperature, and clutch status.

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

[0104] In step 716, when multiple engine crankshaft acceleration change events are detected, alarm circuit 326 executes a second correction method or slow correction method to determine whether the engine crankshaft acceleration change event is caused by a slippage event or an engine misfire event. For example, when multiple engine crankshaft acceleration change events are detected over a relatively long period of time (e.g., 2 seconds to 60 seconds) (optionally, the period of time may be several minutes) and engine torque is high during the period of time, a slippage event, rather than an engine misfire event, is in progress. In one embodiment, slippage events are investigated based on identifying one of fuel cut-off, low torque, and high torque conditions. During the fuel cut-off condition, if there is a change in the crankshaft signal, the engine crankshaft acceleration change event is classified as a slippage event. During the low torque condition, if the amplitude change of the crankshaft signal is higher than a certain threshold, the engine crankshaft acceleration change event is classified as a slippage event. During the high engine torque condition, the engine crankshaft acceleration change event is classified as an engine misfire event. In one example, if an engine crankshaft acceleration variation event cannot be classified as a slippage event, it is classified as an engine misfire event. In another example, if an engine misfire event is detected, the fuel injector of the misfired cylinder is deactivated. Similar to the first correction method, it is advantageous to achieve accurate diagnosis of engine crankshaft acceleration variation events through a second correction method or a slow correction method.

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

[0106] An example of an engine crankshaft acceleration variation event is categorized as... Figure 8 The system provides information on slippage or engine misfire incidents. Steering. Figure 8 Provides engine crankshaft acceleration change event detection logic 800.

[0107] As shown in box 810, monitoring circuitry 322 monitors engine crankshaft position values ​​using input from engine crankshaft position sensor 802, engine rpm values ​​using input from engine rpm sensor 804, and the shiftable transmission input shaft rpm value using input from downstream rpm sensor 806. The exemplary downstream rpm sensor 806 is positioned to determine the rotational speed of a shaft ultimately driven by the CVT's output shaft, such as the shiftable transmission's input shaft, output shaft, wheel speed sensor, and half-shaft. If the shaft monitored by sensor 806 is a shiftable transmission or a downstream output shaft of the shiftable transmission, a gear position sensor 807 is also included (see [link to sensor 806]). Figure 8 This indicates the gear ratio of the shiftable transmission. Based on monitored values, as shown in box 812, detection circuit 324 detects crankshaft acceleration change events. Crankshaft acceleration change events are detected by measuring the rate of acceleration or deceleration of the crankshaft acceleration signal based on the crankshaft rotation angle (e.g., in increments such as 1°, 2°, 5°, 10°, 30°, and 90° of rotation), which can be determined based on engine crankshaft position sensor 802 and engine rpm sensor 804. Exemplary crankshaft acceleration change events include engine misfire events and CVT failure events, both exhibiting recurring patterns over time.

[0108] As shown in box 814, processing sequence 800 determines the interaction frequency that would be associated with the damaged CVT belt. As shown in box 816, detection circuit 324 monitors the time window acceleration or deceleration rate of the observed crankshaft acceleration signal. If an observed crankshaft acceleration change event is detected, alarm circuit 326 compares the frequency of the observed crankshaft acceleration change event with the determined interaction frequency of the damaged CVT belt, as shown in box 818. If the frequency of the observed crankshaft acceleration change event 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, alarm circuit 326 provides a status indication to the vehicle operator. Alternatively, in the event of an engine misfire event, fuel supply to the misfired cylinder may be stopped, or both fuel and spark supply to the misfired cylinder may be stopped. The next time the vehicle is restarted by pressing the button, the fuel supply to the cylinders or the fuel and spark supply is reset.

[0109] In one implementation, the first threshold quantity is an absolute quantity in Hertz, such as 100 Hertz. In another implementation, the first threshold quantity is a percentage quantity. An exemplary percentage is within approximately 10% of the determined interaction frequency of the damaged CVT belt. In one implementation, the frequency of observed crankshaft acceleration change events is compared with the determined interaction frequency of the damaged CVT belt and with a multiple of the determined interaction frequency of the damaged CVT belt.

[0110] Reference Figure 9 An exemplary processing sequence 840 for determining the interaction frequency of a damaged CVT belt is shown. As shown in block 842, detection circuitry 324 detects the engine output speed (E) from engine rpm sensor 804. 速度 And as shown in box 844, the transmission input speed (T) from the transmission input shaft rpm sensor 806 is detected. 速度 As shown in box 846, the CVT ratio (CVT) of the CVT is determined based on the detected engine output speed and transmission input speed. 比率 ).

[0111] As shown in box 848, based on a determined CVT ratio (CVT 比率 ) and detected engine output speed (E 速度 To determine the pitch circle diameter (DP) of the transmission clutch 202 of CVT 200. 直径 Pitch circle diameter (DP) 直径 The pitch circle diameter corresponds to the diameter of the transmission clutch 202 ridden by the drive belt 206. As understood in the art, the gap between pulleys 208 and 210 is adjustable, resulting in the transmission clutch 202 having a number of possible pitch circle diameters. In one example, diagnostic circuit 302 refers to lookup table 850 provided in database 304 to determine the pitch circle diameter of the transmission clutch 202. Diagnostic circuit 302 will determine the CVT ratio (CVT ratio) of the CVT. 比率 ) and detected engine speed (E 速度 The input is provided to lookup table 850, which returns the determined CVT ratio (CVT) provided. 比率 ) and detected engine speed (E 速度 The associated pitch circle diameter (DP) 直径 In one example, diagnostic circuit 302 selects from lookup table 850 the CVT ratio (CVT) that has the closest corresponding determination. 比率 ) and detected engine speed (E 速度 The pitch circle diameter (DP) 直径 ).

[0112] As shown in box 852, based on the determined pitch circle diameter (DP) 直径 The diagnostic circuit 302 determines the linear belt speed (belt speed) of the CVT belt 206. 速度 As shown in box 854, the CVT belt has a linear belt speed of 206 (belt speed). 速度 The known lengths of the CVT belt 206 and CVT belt 206 are used by the diagnostic circuit 302 to determine the frequency of interaction between the points on the CVT belt 206 and the drive clutch 202. 频率 If CVT strip 206 has a damaged area, the damaged area will interact with the area at a frequency known as the damaged CVT strip frequency from box 854 (the strip). 频率 The determined frequency of the belt interacts with the transmission clutch 202. Exemplary belt damage includes rotational burning damage, missing gears on the CVT belt, and rope popping.

[0113] Reference Figure 10 An exemplary processing sequence 900 is shown. The processing sequence 900 adjusts the peak output power of the power source 10 based on the determination of excessive energy accumulation within the CVT 200.

[0114] As shown in box 902, the diagnostic circuit 302 determines the amount of energy (E) input to the CVT 200. 入 As shown in box 904, the diagnostic circuit 302 also determines the amount of thermal energy (E) leaving the CVT 200. 出 In one implementation, 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 leaving the CVT is determined based on the thermal properties of the air flowing through the CVT 200.

[0115] As shown in box 906, the diagnostic circuit 302 directs the energy (E) into the CVT 200. 入 ) and the heat energy leaving CVT 200 (E 出 A comparison is made to determine whether energy accumulates within the CVT 200. Energy accumulation within the CVT 200 causes an increase in the temperature of belt 206 in the CVT 200. When (E 出 ) less than (E 入 When ), energy accumulates within the CVT 200.

[0116] If energy accumulates within CVT 200, diagnostic circuit 302 compares the amount of accumulated energy with a threshold level, as shown in box 908. If the amount of accumulated energy exceeds the threshold level, diagnostic circuit 302 induces energy (E) input to CVT 200, such as by reducing the peak output power or peak output torque of power source 106. 入The reduction of the peak output power of the power source 106 is shown in box 910. In one embodiment, the reduction of the peak output power of the power source 106 is gradual to avoid a rapid decrease in the peak output power of the power source 106.

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

[0118] Reference Figure 11 The amount of energy (E) used to determine the energy entering the CVT 200 is shown. 入 An exemplary processing sequence 930. As shown in block 932, diagnostic circuit 302 determines power source 106, illustratively, the output power level of an internal combustion engine (engine). 功率 In one example, the output power level (engine) 功率 For example, it is determined by multiplying the calculated torque output of the engine by the engine speed. Then, as shown in box 934, the diagnostic circuit 302 retrieves the CVT clutch efficiency (clutch efficiency) from the CVT clutch efficiency diagram or lookup table 936. 效率 ).

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

[0120] Reference Figure 12 The diagram shows the energy (E) used to determine the energy leaving the CVT 200. 出An exemplary processing sequence 960. As shown in block 962, diagnostic circuit 302 determines the air temperature of the air entering the interior of CVT 200 via air supply duct 230. As shown in block 964, based on the temperature reading and heat transfer coefficient 966, diagnostic circuit 302 determines the amount of energy (E) leaving CVT 200 based on CVT clutch airflow model 968. 出 The CVT clutch airflow model is based on engine speed (sensor 804), downstream drivetrain shaft speed (sensor 806), gear position (sensor 807), and vehicle altitude. Vehicle altitude can be determined based on atmospheric pressure measured by an atmospheric pressure sensor or on location values ​​provided by a GPS system. In one embodiment, the outlet temperature of the airflow in exhaust pipe 238 is also monitored and used to determine the energy leaving CVT 200.

[0121] This disclosure can also be configured as follows:

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

[0123] A detection circuit is used to detect at least one engine crankshaft acceleration change event of the vehicle;

[0124] The monitoring circuitry is used to determine at least one operating parameter received from one or more sensors associated with the operation of the CVT; and

[0125] The alarm circuit uses the at least one operating parameter to determine when the at least one detected change in engine crankshaft acceleration is related to a fault in the CVT's drive belt.

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

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

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

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

[0130] Option 6. The diagnostic method according to any one of Options 1 to 5 further includes detecting the at least one engine crankshaft acceleration change event based on the change pattern of the operating parameters 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 the time period of the change pattern is greater than a predetermined time period.

[0133] Option 9. The diagnostic method according to any one of Options 6 to 8 further includes determining whether the magnitude of the change pattern is significant.

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

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

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

[0137] The monitoring circuitry is used to determine at least one operating parameter received from one or more sensors associated with the operation of the CVT;

[0138] A detection circuit is used to detect at least one belt slippage event of the CVT's drive belt;

[0139] The alarm circuit uses at least one operating parameter to determine when the at least one detected belt slippage event is related to an impending failure of the CVT's drive belt; and

[0140] The alarm circuit is used to notify the driver of an impending failure of the drive belt before the belt or drivetrain of the vehicle is damaged.

[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 according to Option 12 or 13 further includes the option of controlling 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 Options 12 to 14 further includes detecting the at least one slippage event by the detection circuit in at least one of a trace control mode and an active control mode.

[0144] Option 16. The diagnostic method according to any one of Options 12 to 15 further includes using the monitoring circuit to receive desired vehicle input parameters.

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

[0146] Option 18. The diagnostic method according to any one of Options 12 to 17 further includes including engine-based parameters 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 the transmission system-based parameters as the at least one operating parameter.

[0148] Option 20. The diagnostic method according to any one of Options 12 to 19 further includes detecting the belt slippage event based on a comparison of engine-based parameters and transmission system-based parameters to predict the impending failure of the transmission belt.

[0149] Option 21. The diagnostic method according to Option 20 further includes determining whether at least one of the engine-based parameters and the transmission system-based parameters 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 slippage event; and automatically adjusting the at least one operating parameter based on a predetermined table.

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

[0152] The monitoring circuitry is used to determine at least one operating parameter received from one or more sensors associated with the operation of the CVT;

[0153] A detection circuit is used to detect at least one critical belt life event of the CVT's drive belt;

[0154] The alarm circuit uses at least one operating parameter to determine when the at least one detected critical belt life event is related to a failure of the CVT's drive belt; and

[0155] The alarm circuit is used to generate information signals related to the lifespan of the drive belt.

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

[0157] Option 25. The diagnostic method according to Option 23 or 24 further includes including engine-based parameters as the at least one operating parameter, wherein the engine-based parameters are 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 system-based parameter as the at least one operating parameter, wherein the transmission system-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 parameters, transmission system 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 Options 23 to 27 further includes 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 text or graphic indications associated with the remaining life of the drive belt.

[0162] Option 30. The diagnostic method according to any one of Options 23 to 29 further includes adjusting at least one of engine-based parameters, transmission system-based parameters, and environmental condition parameters based on the at least one detected critical band life event.

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

[0164] Determine the amount of input energy supplied by the internal combustion engine to the CVT;

[0165] Determine the amount of output heat energy leaving the CVT;

[0166] The amount of accumulated energy in the CVT is determined based on the amount of input energy and the amount of output thermal energy.

[0167] The amount of accumulated energy is compared with 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. The diagnostic method according to Option 31, wherein the step of reducing the amount of input energy includes the step of reducing the power supplied by the internal combustion engine to the CVT.

[0170] Option 33. The 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. The diagnostic method according to any one of Options 31 to 33, wherein the amount of output thermal energy is determined based on the fluid characteristics of the CVT.

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

[0173] Determine the output power of the internal combustion engine;

[0174] The efficiency of the CVT clutch is determined based on the determined output power; and

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

[0176] Option 36. The 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] Option 37. The diagnostic method according to any one of Options 31 to 36, wherein the step of determining the amount of output heat energy leaving the CVT includes the following steps:

[0178] Determine the air temperature of the air entering the CVT; and

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

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

[0181] Detect multiple engine crankshaft acceleration change events;

[0182] Determine the frequency of the plurality of engine crankshaft acceleration variation events;

[0183] Determine the CVT belt interaction frequency of the CVT's drive belt; and

[0184] Based on the comparison between the frequency and the interaction frequency of the CVT belt, the multiple engine crankshaft acceleration change events are classified into one of the engine misfire event and the CVT belt damage event.

[0185] Option 39. The diagnostic method according to any one of Options 31 to 38, wherein the step of determining the CVT belt interaction frequency of the CVT transmission belt includes the following steps:

[0186] Determine the pitch circle diameter of the CVT's transmission clutch;

[0187] The linear speed of the CVT's drive belt is determined based on the determined pitch circle diameter of the transmission clutch and the rotational speed of the CVT's drive shaft; and

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

[0189] The detailed description and examples described above are given for illustrative and descriptive purposes only and are not intended to be limiting. For example, the described operations can be performed in any suitable manner. The methods can be executed in any suitable order while still providing the described operations and results. Therefore, it is contemplated that this embodiment covers any and all modifications, variations, or equivalents falling within the scope of the basic principles disclosed above and claimed herein. Furthermore, while the above description describes hardware in the form of a processor executing code, hardware in the form of a state machine, or dedicated logic capable of producing the same effect, other structures are also contemplated.

Claims

1. A vehicle diagnostic method for a vehicle, the vehicle including an internal combustion engine and a continuously variable transmission operatively coupled to the internal combustion engine, the method comprising the following steps: Determine the amount of input energy supplied by the internal combustion engine to the continuously variable transmission; Determine the amount of output heat energy leaving the continuously variable transmission; The amount of accumulated energy in the continuously variable transmission is determined based on the amount of input energy and the amount of output heat energy. The amount of accumulated energy is compared with a threshold. as well as In response to the amount of accumulated energy satisfying the threshold, the amount of input energy is reduced to prevent the energy accumulated in the continuously variable transmission (CVT) from causing the temperature of the CVT belt to rise above the threshold and to limit damage to the CVT belt. The determination of the amount of output heat energy leaving the continuously variable transmission includes: Determine the air temperature of the air entering the continuously variable transmission; and The amount of output heat energy leaving the continuously variable transmission (CVT) is determined based on the CVT clutch airflow model, heat transfer coefficient, and determined air temperature.

2. The diagnostic method according to claim 1, wherein, The step of reducing the amount of input energy includes reducing the power supplied by the internal combustion engine to the continuously variable transmission.

3. The diagnostic method according to claim 1 or 2, wherein, The amount of input energy is determined based on the mechanical input characteristics of the continuously variable transmission.

4. The diagnostic method of claim 1, wherein, The amount of output heat energy is determined based on the fluid characteristics of the continuously variable transmission.

5. The diagnostic method of claim 1, wherein, The step of determining the amount of input energy supplied by the internal combustion engine to the continuously variable transmission includes the following steps: Determine the output power of the internal combustion engine; The efficiency of the continuously variable transmission (CVT) clutch is determined based on the determined output power; and The amount of input energy supplied to the continuously variable transmission (CVT) is determined based on the determined output power and the determined CVT clutch efficiency.

6. The diagnostic method according to claim 5, wherein, The step of determining the continuously variable transmission (CVT) clutch efficiency based on the determined output power includes retrieving the determined CVT clutch efficiency from a database.

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