System and method for volumetric efficiency diagnostics of engine

Abstract

A method and system for performing diagnostic services on a vehicle having an internal combustion engine based on volumetric efficiency calculations of the engine. The volumetric efficiency calculation is based on mass flow data from the mass flow sensor. A volumetric efficiency value below a threshold may be related to a plurality of operating conditions of the engine. The guided service operations may include instructions by a user to perform service operations to improve vehicle operating conditions.

Description

Technical Field

[0001] The present disclosure relates to vehicle diagnostics. In particular, the present disclosure relates to diagnostics related to air flow and volumetric efficiency of an internal combustion engine. Background Art

[0002] Volumetric efficiency is a measure of how much air is passed through an internal combustion engine compared to the theoretical maximum amount of air that can pass during each revolution. A theoretical maximum efficiency of 100% is not possible, but very high efficiencies can be observed in properly maintained engines operating at high loads. At lower loads, the amount of intake air is reduced, and the expected volumetric efficiency is similarly reduced.

[0003] A quick indication of volumetric efficiency is useful in quickly diagnosing potential problems with engine operation. Contemporary tools that measure volumetric efficiency work on intermittent measurements and provide the measurement results to the user without additional context. What is desired is a tool that provides a quick measurement of volumetric efficiency and additional context to provide the user with information suitable for quickly performing service or repairs on the engine. Summary of the invention

[0004] One aspect of the present disclosure relates to a diagnostic method for an internal combustion engine, the method comprising establishing a data connection between a diagnostic processor and a vehicle communication bus (VCB) of a vehicle using the engine, requesting mass airflow data from the VCB, displaying the mass airflow data on a display in data communication with the diagnostic processor in response to receiving the mass airflow data from the VCB, generating an efficiency indicator of the engine volumetric efficiency based on the mass airflow data, generating a diagnostic indicator based on the volumetric efficiency, generating a diagnostic indicator based on the volumetric efficiency, and displaying the efficiency indicator and the diagnostic indicator on the display. The mass airflow data indicates the mass airflow of the combined cylinders of the engine during operation of the engine. The method includes an additional step, wherein the VCB obtains the mass airflow data from a sensor in data communication with the VCB, the diagnostic indicator indicates normal operation of the engine in response to the volumetric efficiency being equal to or greater than a threshold, and the diagnostic indicator indicates an engine fault in response to the volumetric efficiency being less than the threshold. The threshold is established using identification data associated with the vehicle, which identification data can be obtained from the VCB in an autonomous manner. In some embodiments, the data communication between the memory and the diagnostic processor utilizes a network connection. In some embodiments, the sensor is disposed in the engine airflow passage between the air filter and the intake manifold.

[0005] Another aspect of the present disclosure relates to a diagnostic system, including a mass airflow sensor, a diagnostic bus in data communication with the mass airflow sensor, a diagnostic processor in data communication with the diagnostic bus, and a display in data communication with the diagnostic processor. The mass airflow sensor generates mass airflow data indicating a mass airflow condition of an engine. In some embodiments, the mass airflow sensor is disposed in an engine airflow passage between an air filter and an intake manifold of the engine. The diagnostic processor is configured to transmit commands to the diagnostic bus and receive data from the diagnostic bus. The diagnostic processor is configured to transmit diagnostic data for output via a display, wherein the diagnostic bus acquires the mass airflow data from the mass airflow sensor, the diagnostic bus transmits the mass airflow data to the diagnostic processor, the diagnostic processor generates a volumetric efficiency of the engine based on the mass airflow data, the diagnostic data indicates normal operation of the engine in response to the volumetric efficiency being equal to or greater than a threshold, and the diagnostic data indicates an engine fault in response to the volumetric efficiency being less than the threshold. Some embodiments include a memory in data communication with the diagnostic processor, the memory having stored thereon an expected mass airflow value for generating a threshold. In some embodiments, the diagnostic processor is configured to generate additional service instructions in response to the volumetric efficiency being less than the threshold. Additional service instructions may be transmitted to a display or other output for use by a user when servicing the engine or other components of the vehicle associated with the engine.

[0006] The above-mentioned aspects and other aspects of the present disclosure will be explained in more detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a schematic illustration of a diagnostic system.

[0008] Figure 2 is a schematic illustration of the engine airflow path.

[0009] Figure 3 is a flow chart illustrating a diagnostic service method for a vehicle.

[0010] Figure 4 is a flow chart illustrating a diagnostic service method for a vehicle. DETAILED DESCRIPTION

[0011] The illustrated embodiments are disclosed with reference to the accompanying drawings. However, it should be understood that the disclosed embodiments are merely intended to be examples that can be implemented in various alternative forms. The drawings are not necessarily drawn to scale, and some features may be enlarged or minimized to show details of specific components. The specific structural and functional details disclosed should not be interpreted as limiting, but as a representative basis for teaching those skilled in the art how to practice the disclosed concepts.

[0012] Figure 11 is a schematic illustration of a diagnostic system according to one embodiment of the teachings disclosed herein. The depicted diagnostic system is directed to a vehicle 100 having an internal combustion engine (not shown) and a vehicle communication bus (VCB) 101. In the depicted embodiment, the vehicle 100 comprises a consumer sedan, but other embodiments may utilize a compact car, a subcompact car, a sports car, a minivan, a crossover, a sport utility vehicle, a multi-purpose vehicle, a light truck, an industrial truck, a motorcycle, a side-by-side recreational vehicle, an on-road recreational vehicle, an off-road recreational vehicle, or any other vehicle utilizing an engine having an airflow path without departing from the teachings disclosed herein.

[0013] In the depicted embodiment, the VCB 101 may include a controller area network (CAN) bus, but other embodiments may include other configurations of the VCB 101 utilizing different diagnostic protocols without departing from the teachings disclosed herein. The VCB 101 includes a diagnostic bus adapted to transmit messages between components of the vehicle 100 and external diagnostic tools. The messages transmitted between the components and the external diagnostic tools may include diagnostic trouble codes (DTCs), or any other diagnostic data useful for external tools to diagnose and service components of the vehicle 100. The sensor 103 is in data communication with the VCB 101 and generates sensor data indicative of vehicle operating conditions. In the depicted embodiment, the sensor 103 includes a mass airflow sensor 103, but other embodiments may include other configurations without departing from the teachings disclosed herein. In the depicted embodiment, the mass airflow sensor 103 may be a standard feature of the vehicle 100, an aftermarket inclusion of the vehicle 100, or a temporary inclusion provided by a technician during diagnostic service of the vehicle 100 without departing from the teachings disclosed herein.

[0014] In the depicted embodiment, the VCB 101 is in data communication with an external diagnostic tool in the form of a scan tool 111. The scan tool 111 includes a human machine interface (HMI) 115 that allows a user to input commands or data and receive information or data from the scan tool 111. In the depicted embodiment, the HMI 115 includes a touch screen display and a plurality of soft keys and hardware buttons, but other embodiments may include other forms of input or output without departing from the teachings disclosed herein.

[0015] Although the external diagnostic device is embodied as a scan tool 111 in the depicted embodiment, in other embodiments it may be embodied as a mobile processing device, a smart phone, a tablet computer, a laptop computer, a wearable computing device, a desktop computer, a personal digital assistant (PDA) device, a handheld processor device, a dedicated processor device, a processor system distributed over a network, a processor system configured in wired or wireless communication, or any other alternative embodiment known to those of ordinary skill in the art.

[0016] The scan tool 111 additionally includes a diagnostic processor 113 and a diagnostic memory 117. The diagnostic processor is adapted to generate commands and communicate other data between the scan tool 111 and the VCB 101. In the depicted embodiment, the diagnostic processor 113 communicates data with the VCB 101 via a wireless data connection, but other embodiments may include different or additional communication protocols without departing from the teachings disclosed herein.

[0017] Wireless data communication may be accomplished via a transceiver circuit 119 of the scan tool 111 in data communication with the VCB 101. In the depicted embodiment, the transceiver circuit 119 is adapted to exchange digital communications with an external device (e.g., the VCB 101). In the depicted embodiment, the transceiver circuit 119 includes a transmitter and a receiver component, but other embodiments may include other configurations with separate transmitters and receivers without departing from the teachings disclosed herein. The transceiver circuit 119 is in data communication with the diagnostic processor 113. The diagnostic processor 113 and the VCB 101 may be configured to communicate wirelessly via one or more of RF (radio frequency) specifications, cellular telephone channels (analog or digital), cellular data channels, Bluetooth specifications, Wi-Fi specifications, satellite transceiver specifications, infrared transmissions, Zigbee specifications, local area networks (LANs), wireless local area networks (WLANs), or any other alternative configurations, protocols, or standards known to those of ordinary skill in the art.

[0018] In some embodiments, the transceiver circuit 119 may alternatively or additionally include a configuration suitable for a wired data connection. In such embodiments, the transceiver circuit 119 may include an on-board diagnostic (OBD) protocol connection, a TCP / IP connection, a local area network (LAN) connection, a plain old telephone service (POTS) connection, an Internet Protocol connection, electrical wiring, a conductive channel, an electrical bus, a fiber optic path, or any other alternative embodiment known to those of ordinary skill in the art.

[0019] The diagnostic processor 113 may provide service-related information stored in the diagnostic memory 113 to a user based on data received from the VCB 101. The diagnostic processor 113 may additionally retrieve data from additional external sources, such as a remote server 121 including a remote processor 123 and a remote memory 127. The remote server 121 additionally includes a remote transceiver 129 for data communication with the scan tool 111. In the depicted embodiment, data communication between the scan tool 111 and the remote server 121 is accomplished via a wireless Internet connection, but other embodiments may include other configurations utilizing a local area network, a direct connection, a wired Internet connection, or any other data communication connection protocol recognized by one of ordinary skill in the art without departing from the teachings disclosed herein.

[0020] In the depicted embodiment, one or both of the diagnostic processor 113 and the remote processor 123 can collect data received from the VCB 101 and store the data in one or both of the associated diagnostic memory 117 or remote memory 121. The collected data can be organized into a corpus of diagnostic history data and then used by the diagnostic processor 113 or the remote processor 123 for machine learning purposes of diagnostic results. In the depicted embodiment, the remote processor 123 restricts access to the diagnostic history data corpus, and the user of the diagnostic processor 113 can pay in exchange for access to the corpus. The payment can be in the form of an ad hoc payment, a subscription payment, a temporary access fee, or some combination thereof. In some embodiments, a combination of payments can be provided to the user, providing different levels of payment to provide access to different parts of the corpus, and the corpus can be organized according to diagnostic severity, component type, or another organization method recognized by a person of ordinary skill in the art when making the present invention.

[0021] In the depicted embodiment, the diagnostic processor 113 may be specifically directed to the analysis of data generated by the mass airflow sensor 103, which may be used to quickly rule out many diagnostics based on volumetric analysis of the mass airflow data generated. By way of example and not limitation, a modern well-regulated engine may be expected to exhibit 80-90% volumetric efficiency during heavy load operation. The diagnostic processor 113 may receive mass airflow data from the mass airflow sensor 103, as well as additional tacheometry data from other sensors in data communication with the VCB 101, and compare these values ​​to a corpus of expected values. In the depicted embodiment, the corpus may include a table of expected values ​​for a particular make and model of vehicle 100 under controlled conditions. The corpus may include a plurality of such value tables comparing engine load and volumetric efficiency values, each of the plurality of tables corresponding to a different make and model of vehicle. Volumetric efficiency data may be provided by VCB 101 , or raw sensor data indicative of total mass airflow may be transmitted to diagnostic processor 103 , and volumetric efficiency may be calculated by diagnostic processor 103 based on the raw data and the known total air volume for the particular make and model of vehicle 100 .

[0022] Figure 2 is a vehicle (eg, vehicle 100; see Figure 1) is a schematic illustration of an airflow circuit 200 of an engine of the type shown in FIG. Intake is accomplished by pulling air through an air filter 201 in direction 203. Airflow continues through the airflow circuit 200, passes through a throttle valve 205, and enters an intake manifold 207. At the intake manifold 207, the air is mixed with fuel through fuel injectors 209 before the air-fuel mixture enters the engine 211. The engine 211 includes a plurality of pistons 213 disposed within a plurality of cylinders 215. The engine 211 utilizes the airflow and the air-fuel mixture to generate motion within the pistons 213, which motion is used to move an associated vehicle. During a four-stroke cycle, air additionally flows out of the engine 211 via an exhaust conduit 217. The mass airflow sensor 103 (see also) Figure 1 ) can measure the total mass airflow through the airflow circuit 200. In the depicted embodiment, the mass airflow sensor 103 is disposed within the path of the airflow circuit 200 immediately after the air filter 201, but in other embodiments, the mass airflow sensor 103 can be disposed elsewhere within the airflow circuit 200 without departing from the teachings disclosed herein. Some embodiments may include additional mass airflow sensors 103 without departing from the teachings disclosed herein.

[0023] If the volumetric efficiency data calculated during a diagnostic test using mass airflow data from the mass airflow sensor 103 is not available for a particular make and model of vehicle 100 (see Figure 1 ) is within the expected operating range, the diagnostic processor 101 (see Figure 1 ) can update HMI 115 (see Figure 1 ) to indicate to the user that the operation of the vehicle 100 is not indicative of a plurality of potential conditions. By way of example and not limitation, a modern engine operating at a relatively high tachometer load may be expected to exhibit a volumetric efficiency of 80-90%. Other vehicles may exhibit different volumetric efficiencies of different values, particularly if the engine is an older model (where lower volumetric efficiencies are expected) or if the engine includes a turbocharger or supercharger assembly (which may operate to force a higher volumetric efficiency, even exceeding the nominal 100% efficiency of the same engine without such an assembly).

[0024] If the calculated volumetric efficiency is lower than the expected condition, the measurement may correspond to one or more of a plurality of known operating conditions of the vehicle 100 that warrant service. By way of example and not limitation, conditions that result in reduced volumetric efficiency may include a failure or suboptimal operation of the mass airflow sensor 103, the air filter 201, the exhaust duct 217, one or more cylinders 215, or a passage of the airflow circuit 200. Service operations for each of these components may be presented to the user to perform in an attempt to correct the reduced volumetric efficiency. During the service, the diagnostic processor 113 may continue to request mass airflow data from the mass airflow sensor 103 and calculate an updated value for the volumetric efficiency. As the user completes each service operation, the HMI 115 may be updated to continuously display the current volumetric efficiency to the user. By way of example and not limitation, the diagnostic processor 113 may request mass airflow data up to 5 times per second, but other embodiments may utilize data requests of different frequencies without departing from the teachings disclosed herein. Thus, the user may perform a near real-time analysis of the volumetric efficiency of the engine 211, including any changes caused by each service operation. By way of example and not limitation, the service operations may include sensor verification of the mass airflow sensor 103, visual inspection and / or replacement of the air filter 201, measurement of air pressure inside the exhaust duct 217, audio analysis of sounds produced during operation of the engine 211, or a compression check to measure the mechanical integrity of the airflow circuit 200. Additional or different service operations may be presented to the user without departing from the teachings disclosed herein. In the depicted embodiment, the service operations may be presented to the user in a particular order, but other embodiments may utilize a different order of suggested service operations without departing from the teachings disclosed herein.

[0025] Figure 3 is a diagram illustrating the use of volumetric efficiency data for a vehicle (eg, vehicle 100; see Figure 1 ) of an engine (e.g., engine 211; see Figure 2 ) is a flowchart of a method for performing diagnostic evaluation. The method begins at step 300, where a vehicle communication bus ("VCB", such as VCB 101; see Figure 1 ) and a diagnostic processor (e.g., diagnostic processor 113; see Figure 1) are established between the VCB and the diagnostic processor. In the depicted embodiment, establishing data communications may additionally include exchanging identification data from the VCB to the diagnostic processor. The identification data may include information identifying the make and model of the vehicle, the make and model of the engine, or other identification data for other components in communication with the VCB. After data communications are established, the method proceeds to step 302 where mass airflow data is requested by the diagnostic processor and transmitted by the VCB. In the depicted embodiment, additional data may be requested from the VCB, such as an indication of an engine associated with the vehicle (e.g., engine 211; see Figure 2 After acquiring the mass airflow data, the volumetric efficiency is calculated at step 304 and an indicator is generated for display via a human machine interface ("HMI", such as HMI 115; see Figure 1 ) is presented to the user. In the depicted embodiment, multiple cycles of data requests are utilized to stabilize the volumetric efficiency value, and the method proceeds to step 306 to determine whether a sufficient number of data exchanges have occurred to reliably calculate a stable volumetric efficiency value. In the depicted embodiment, the volumetric efficiency measurement may produce a weighted average and a peak volumetric efficiency value for the volumetric efficiency. By way of example and not limitation, the weighted average volumetric efficiency measurement may be a weighted arithmetic average of a finite number of recent instantaneous volumetric efficiency calculations. By way of example and not limitation, the peak volumetric efficiency may be the maximum calculated value of the instantaneous volumetric efficiency calculations within a predetermined operating time window (e.g., the last 5 minutes of operation) during engine operation. Other embodiments may include different volumetric efficiency measurements without departing from the teachings disclosed herein.

[0026] Once the specified data set has been acquired and the appropriate volumetric efficiency data has been calculated, the data can be presented to the user via the HMI and the method proceeds to step 308, where the volumetric efficiency data is compared to the expected range for the make, model, and tachometer load of the vehicle during operation. In the depicted embodiment, the expected range can be specified by one or more thresholds that indicate the minimum efficiency for expected operation of vehicles of the same make, model, and age as the vehicle under test. If the volumetric efficiency is greater than the threshold, the engine is operating at the expected volumetric efficiency and the method can proceed to step 310, where all related possible diagnoses can be rejected from the service requirement. Advantageously, utilizing the volumetric efficiency calculation can quickly dismiss many possible diagnostic steps to determine what service is required for the engine. However, if the volumetric efficiency data is outside the expected range, the method can alternatively proceed to step 312, where a list of related diagnostic and service operations can be presented to the user for completion to return the vehicle to the expected operating condition.

[0027] Figure 3The method depicted in presents one embodiment of a diagnostic method according to the invention disclosed herein.Other embodiments may include additional or different steps without departing from the teachings disclosed herein.

[0028] Figure 4 is a flow chart of an alternative embodiment of a volumetric efficiency diagnostic according to the teachings disclosed herein.

[0029] The method begins at step 400, where a vehicle communication bus ("VCB", such as VCB 101; see Figure 1 ) and a diagnostic processor (e.g., diagnostic processor 113; see Figure 1 ) are established between the VCB and the diagnostic processor. In the depicted embodiment, establishing data communications may additionally include exchanging identification data from the VCB to the diagnostic processor. The identification data may include information identifying the make and model of the vehicle, the make and model of the engine, or other identification data for other components in communication with the VCB. After data communications are established, the method proceeds to step 402 where mass airflow data is requested by the diagnostic processor and transmitted by the VCB. In the depicted embodiment, additional data may be requested from the VCB, such as an indication of an engine associated with the vehicle (e.g., engine 211; see Figure 2 After acquiring the mass airflow data, the volumetric efficiency is calculated at step 404 and an indicator is generated for display via a human machine interface ("HMI", such as HMI 115; see Figure 1 ) is presented to the user. In the depicted embodiment, the HMI of the method includes at least a display, but other embodiments may include different or additional features known to those of ordinary skill without departing from the teachings disclosed herein.

[0030] In step 406, the generated indicator is presented to the user via the HMI to provide the user with near real-time updated values. In the depicted embodiment, multiple cycles of data requests are utilized to stabilize the volumetric efficiency value, and the method proceeds to step 408 to determine whether there have been a sufficient number of data exchanges to reliably calculate a stable volumetric efficiency value. If not, the method returns to step 404 to request additional data. In the depicted embodiment, the volumetric efficiency measurement may produce a weighted average and a volumetric efficiency peak for volumetric efficiency. By way of example and not limitation, the weighted average volumetric efficiency measurement may be a weighted arithmetic average of a finite number of recent instantaneous volumetric efficiency calculations. By way of example and not limitation, the volumetric efficiency peak may be the maximum calculated value of an instantaneous volumetric efficiency calculation within a predetermined operating time window during service (e.g., the last 5 minutes of operation). Other embodiments may include different volumetric efficiency measurements without departing from the teachings disclosed herein.

[0031] Once the specified data set has been acquired and the appropriate volumetric efficiency data has been calculated, the data may be presented to a user via the HMI at step 410 and the method proceeds to step 412 where the volumetric efficiency data is compared to an expected range for the vehicle make, model, and tachometer load during operation. In the depicted embodiment, the expected range may be specified by one or more thresholds that indicate a minimum efficiency for expected operation of vehicles of the same make, model, and age as the vehicle under test. If the volumetric efficiency is greater than the threshold, the engine is operating at the expected volumetric efficiency and the method may proceed to step 414 where all related possible diagnostics may be dismissed from the service requirement and the HMI updated with the final volumetric efficiency reading at step 416 before the method is completed. Advantageously, utilizing the volumetric efficiency calculation may quickly dismiss many possible diagnostic steps to determine what service is required for the engine.

[0032] However, if the volumetric efficiency data is outside of the expected range, the method may instead proceed to step 418 where a user or diagnostic processor may establish a connection to a remote server (e.g., remote server 121; see Figure 1 ) data communication, accommodating additional diagnostic and service information in a memory (e.g., remote memory 127; see Figure 1 ).

[0033] After establishing data communication, the method continues to check whether the user is authorized to access data from the remote server at step 420. Access to the remote server can be controlled based on a state associated with the user or the diagnostic processor stored in the memory of the server. In the depicted embodiment, access to the information of the remote server is controlled by a paywall, and the user can obtain authorization by paying the operator of the remote server. Payment can include a subscription-based model that authorizes access to all or part of the information stored on the remote server as long as the subscription payment is kept up to date. Payment can include an ad hoc model in which the user pays for access to a specific portion of the information stored by the remote server. In the ad hoc model, access rights can be granted permanently or for a limited duration in response to the receipt of an ad hoc payment. Payment can include single-point access to different parts of the information stored on the remote server, where the user pays once in advance and retains permanent access to the corresponding selected parts of the information stored on the remote server. Access can also be organized into different customer levels, where users paying at different rates are authorized to access different amounts of information. In some embodiments, other services can be enabled based on the authorization level. As an example and not limitation, the remote server may provide additional service instructions to a user with sufficient authorization to guide the user through service operations to resolve the diagnosis based on the data received from the VCB. These instructions may be transmitted to the diagnostic processor and presented via the HMI, but other embodiments may include other arrangements without departing from the teachings disclosed herein.

[0034] In some embodiments, the memory storage of the remote server may include a corpus of diagnostic history data, and the corpus may be utilized by the machine learning method executed by the diagnostic processor to selectively present to the user service operations that may be applicable to the instantaneous diagnosis of the vehicle. After the vehicle service is successfully completed, the successful results of the service operation may be transmitted back to the remote server to be additionally stored as part of the corpus. Thus, over time, the corpus provides a more robust and comprehensive data set for the machine learning method to assist the diagnostic processor in performing diagnostic assessments of vehicles of a particular make and model. In some embodiments, information requiring authorization may be stored locally in a memory that is in data communication with the diagnostic processor and may alternatively be accessed via a password, fingerprint scan, voiceprint identification, retinal scan, facial recognition scan, or any other security mechanism recognized by a person of ordinary skill in the art without departing from the teachings disclosed herein.

[0035] If access is not authorized at step 420, the method updates the HMI at step 422 to notify the user of this. In the depicted embodiment, step 420 additionally includes a sub-step of providing the user with an opportunity to obtain authorization via payment. The payment request can be one or more of a subscription payment, an ad hoc payment, or a single-point payment. If the user denies the request, the method proceeds to step 422, updates the interface with the latest information about the diagnosis, and then ends. If the user has or obtains authorization, the method instead proceeds to step 424, where the steps of performing one or more service actions are obtained from a remote server and presented via the HMI at step 426. The method then continues at step 428 to guide the user through the steps of the first service operation. One or more service operations can be presented to the user, and the diagnostic processor can pre-select which service operation is for the user's next operation, or the user can select which is preferred without departing from the teachings disclosed herein.

[0036] By way of example and not limitation, the additional service instructions may relate to one or more additional service operations adapted to address potential vehicle conditions that may result in suboptimal volumetric efficiency. The additional service operations may include sensor verification, exhaust pressure measurement, air filter check, cylinder compression verification, or audio analysis. In sensor verification, one or more mass airflow sensors (e.g., mass airflow sensor 103; see Figure 1 ) can be tested or calibrated to determine whether the data generated is erroneous. In exhaust pressure measurement, the exhaust conduit (e.g., exhaust conduit 217; see Figure 2 ) and the pressure readings are used to determine if there is a blockage or leak in the exhaust duct. During an air filter inspection, the air filter (e.g., air filter 201; see Figure 2) is visually inspected to ensure the condition of whether to replace the filter with a new one. In some embodiments, the visual inspection of the air filter can be completed by a machine learning diagnostic of a diagnostic processor, which uses a camera associated with the diagnostic processor to generate image data depicting the air filter and its current condition. The machine learning diagnostic can use a corpus of image data stored on a local or remote server for comparison between the vehicle's air filter and the air filter observed during a previous service operation. Other embodiments may include a visual inspection by the user, but without departing from the teachings disclosed herein, a graphical representation of the condition of the air filter that needs and does not need to be replaced can be additionally presented to the user for visual reference. In a cylinder compression check, the spark plug can be removed from the engine to allow a pressure sensor to be inserted into one or more cylinders of the engine (e.g., cylinder 215) to determine whether the integrity of the cylinder is satisfactory. In audio analysis, the sound of the engine during operation can be auditorily inspected to determine one or more other potential operating conditions of the engine. In some embodiments, the audio analysis of the engine can be completed by a machine learning diagnostic of a diagnostic processor, which uses a microphone associated with the diagnostic processor to generate audio data depicting the sound of the engine during operation. The machine learning diagnostics may utilize a corpus of audio data stored locally or on a remote server for comparison between the audible operating sounds of the vehicle and the audible operating sounds of previous vehicles during previous service operations. Other embodiments implement a listening check performed by a user, but may additionally present the user with recorded audio depicting engines of similar makes and models as the vehicle in service that did and did not require additional service operations for auditory comparison without departing from the teachings disclosed herein.

[0037] After the service operation is completed, the method checks at step 430 to see if the volumetric efficiency of the engine is within one or more expected ranges. If the volumetric efficiency is within the expected range, the previous service operation is deemed to have resolved the problem, and this information is transmitted back to the remote server for inclusion in the corpus of diagnostic history data. If the service operation did not bring the volumetric efficiency within the expected threshold, the method proceeds to step 434 to determine whether any additional service operations can be performed from the list of service operations obtained in step 424. If any service steps remain, the method proceeds to step 430, in which the system is updated with new volumetric efficiency data and the list of service operations is updated to remove the most recently completed service operation before the method returns to step 426 to present the next service operation. This iterative process continues until the volumetric efficiency is found to be within the specified threshold at step 430, or no additional service steps exist at step 434. If no additional service steps exist, the user is notified of this status and the method ends. If some additional service steps are available that the user is not currently authorized to access, then at step 434, the user may be presented with an option to pay for the additional access, and during the next iteration of the service operation, these additional service operations may be made available at step 430. In this manner, users utilizing the ad hoc payment structure may continue to pay only for the service information they need on an as-needed basis. If the user declines, or the total list of service operations is otherwise exhausted, the method ends at step 440.

[0038] In some embodiments, in steps 424, 426, and 428, a list of service operations may be provided to the user instead, but the user may not be provided with specific steps to complete the service operations. This advantageously allows a user who is an experienced technician to perform service operations without interrupting the normal operation of the diagnostic processor during service to provide unnecessary information. In such an embodiment, the list of service operations may be viewed by a user with a lower authorization status than the guidance instructions for one or more additional service operations without departing from the teachings disclosed herein.

[0039] Some embodiments may not include steps 420-424 without departing from the teachings disclosed herein. Some embodiments may utilize fewer or additional updating steps (eg, steps 406, 410, 422, 430, and 432) without departing from the teachings disclosed herein.

[0040] Although exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the disclosed apparatus and methods. Rather, the words used in the specification are descriptive rather than restrictive, and it should be understood that various changes may be made without departing from the spirit and scope of the disclosure as claimed. The features of various implementation embodiments may be combined to form further embodiments of the disclosed concepts.

Claims

1. A diagnostic method for an internal combustion engine, the method comprising: establishing a data connection between the diagnostic processor and a vehicle communication bus (VCB) of a vehicle using the engine; requesting mass airflow data from the VCB, the mass airflow data indicating mass airflow of combined cylinders of the engine during operation of the engine; in response to receiving the mass airflow data from the VCB, displaying the mass airflow data on a display in data communication with the diagnostic processor; generating an efficiency indicator of engine volumetric efficiency based on the mass airflow data; generating a diagnostic indicator based on the volumetric efficiency; and Shows efficiency indicators and diagnostic indicators on the display, in The VCB acquires mass airflow data from sensors that are in data communication with the VCB. In response to the volumetric efficiency being equal to or greater than the threshold, the diagnostic indicator indicates normal operation of the engine, and In response to the volumetric efficiency being less than a threshold, a diagnostic indicator indicates an engine fault.

2. The diagnostic method according to claim 1, wherein: The threshold is established using identification data associated with the vehicle.

3. The diagnostic method according to claim 2, wherein: The identification data is obtained from the VCB.

4. The diagnostic method according to claim 2, further comprising: transmitting the mass airflow data, the volumetric efficiency, and the identification data to a memory in data communication with the diagnostic processor, the memory storing thereon a corpus of diagnostic history data; and Append mass airflow data, volumetric efficiency, and identification data to the corpus of diagnostic history data.

5. The diagnostic method according to claim 4, wherein: Data communication between the memory and the diagnostic processor utilizes a network connection.

6. The diagnostic method according to claim 1, wherein: The sensor is disposed in an engine air flow passage between an air filter and an intake manifold of the engine.

7. The diagnostic method according to claim 1, wherein: The diagnostic indicator includes additional service instructions in response to a volumetric efficiency being below a threshold. 8 . The diagnostic method of claim 7 , wherein the additional service instructions include instructions to perform a sensor verification, an exhaust pressure measurement, an air filter check, a cylinder compression check, or an audio analysis.

9. The diagnostic method according to claim 1, wherein: The indicator of volumetric efficiency includes a moving average for volumetric efficiency, the moving average determined using a series of mass airflow data measurements corresponding to a predetermined time window during engine operation.

10. A diagnostic system comprising: a mass airflow sensor disposed in an airflow passage of the engine between an air filter and an intake manifold of the engine, the mass airflow sensor generating mass airflow data indicative of a mass airflow condition of the engine; a diagnostic bus for data communication with a mass airflow sensor; a diagnostic processor in data communication with the diagnostic bus, the diagnostic processor being configured to transmit commands to the diagnostic bus and receive data from the diagnostic bus; and a display in data communication with the diagnostic processor, the diagnostic processor being configured to transmit diagnostic data for output via the display, in The diagnostic bus obtains mass airflow data from the mass airflow sensor, The diagnostic bus transmits mass airflow data to the diagnostic processor, The diagnostic processor generates the volumetric efficiency of the engine based on the mass airflow data. In response to the volumetric efficiency being equal to or greater than the threshold, the diagnostic data indicates normal operation of the engine, and In response to the volumetric efficiency being below a threshold, the diagnostic data indicates an engine fault.

11. The diagnostic system of claim 10, further comprising a memory in data communication with the diagnostic processor, the memory having stored thereon an expected mass airflow value used to generate the threshold value.

12. The diagnostic system according to claim 11, wherein: The memory also has stored thereon a plurality of expected mass airflow values, each of the plurality of mass airflow values ​​corresponding to a particular model and operating condition of the engine under test, in The diagnostic bus transmits identification data to the diagnostic processor, which is associated with the model of the engine. The diagnostic bus transmits tachometer data to the diagnostic processor, the tachometer data being indicative of the load of the engine, and The diagnostic processor utilizes the identification data and the tachometer data to generate volumetric efficiency data.

13. The diagnostic system of claim 10, wherein The diagnostic processor is configured to generate additional service instructions in response to the volumetric efficiency being below a threshold and to transmit the additional service instructions to the display.

14. The diagnostic system according to claim 13, wherein: The additional service instructions include instructions to perform a sensor verification, an exhaust pressure measurement, an air filter check, a cylinder compression check, or an audio analysis.

15. The diagnostic system of claim 10 further comprising a memory in data communication with the diagnostic processor, the memory storing thereon a corpus of diagnostic history data, the diagnostic processor utilizing the corpus to generate additional service instructions.

16. The diagnostic system of claim 15, wherein the memory comprises a remote memory, and wherein data communication between the remote memory and the diagnostic processor comprises a network connection.

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