ALTERNATOR MONITORING SYSTEM

Technical Field

This disclosure relates to apparatus for monitoring the electrical charging system of an internal combustion engine, and particularly for monitoring the alternator.

An internal combustion engine with a starter battery will usually have an electrical charging system including an alternator, which is powered by the engine and charges the battery while the engine is in operation.

It can be difficult to diagnose faults in the electrical charging system. This sometimes leads to unnecessary removal of the alternator which is then subjected to a complex test procedure, which often reveals that the alternator is not faulty. If a fault is identified then it is often difficult to understand what caused the fault to develop.

Monitoring the electrical charging system to identify potential problems can present its own difficulties. Many vehicular engines do not support remote data collection (vehicle telematics). The same is true of many stationary engines, e.g. standby generator sets as used for backup power supplies in hospitals, for which the charging system will include a secondary engine that runs only to maintain the charge in the starter batteries. If a fault develops in the charging system then it may not be identified until the generator is called on line.

U.S. Patent No. 6,363,303 discloses an apparatus for testing an alternator, including a vibration sensor which is positioned proximate the alternator to sense vibrations generated by operation of the alternator. A diagnostic system diagnoses the condition of the alternator based on the sensed vibrations, for example, by sensing signal components indicative of a bearing failure. Various signal processing techniques can be used to reject signals which are not associated with alternator failure and to reduce the effects of ambient noise. Alternatively, a direction sensor can be aimed at the alternator such that it is less sensitive to surrounding noise. In another aspect, the device includes a temperature sensor for sensing temperature variations in the alternator indicative of a bearing failure.

The device can be permanently mounted in the vehicle or used temporarily during service operations. Diagnostic information produced by the device can be stored in the vehicle diagnostics system or transmitted wirelessly, e.g. via the internet to the user or to remote test equipment.

U.S. Patent No. 9,761,066 discloses a monitoring unit that is connectable to the vehicle electrical system to monitor voltage output from the battery and alternator. The monitoring unit is arranged to send a wireless signal to a receiver unit (e.g. a cellular telephone) responsive to detecting a malfunction.

U.S. Patent No. 7,391,186 discloses vehicle alternator failure monitoring system including an alternator voltage control device that transmits a serial signal, indicative of the status of the alternator, to the vehicle ECU. The data content of the signal varies depending on whether an alternator fault is detected, reducing the processing burden on the ECU. The alternator voltage control device may include a memory for storing data indicative of an alternator fault at the time the fault is detected.

Summary of the Disclosure

In accordance with the present disclosure there is provided a monitoring system for monitoring an electrical charging system of an internal combustion engine, said electrical charging system including an alternator.

The monitoring system comprises a device that is is mounted or mountable in use, in or on the alternator, the device being configured to sense electrical parameters of the electrical charging system, and at least one ambient condition exogenous to the alternator. The device includes a timekeeping arrangement, and a memory, and is configured to store, in the memory, data representing each of the sensed electrical parameters and the sensed at least one ambient condition, together with a time and date of the data as indicated by the timekeeping arrangement.

In another aspect there is provided an alternator including the novel device.

In another aspect there is provided an apparatus including an alternator for use in an electrical charging system of an internal combustion engine, together with the novel device. The alternator includes a first external casing, and the device includes a second external casing. The first external casing is replaceable by the second external casing.

Further features and advantages will become apparent from the following illustrative embodiments which will now be described, purely by way of example and without limitation to the scope of the claims, and with reference to the accompanying drawings, in which:

Fig. 1 illustrates the electrical charging system of an internal combustion engine, including a conventional alternator.

Fig. 2 shows the conventional alternator in side and end view.

Fig. 3 shows a first embodiment of the novel device, incorporated into an end cover for an alternator.

Fig. 4 shows the alternator of Fig. 2 with the conventional end cover replaced by the embodiment of Fig. 3.

Reference numerals and characters that appear in more than one of the figures indicate the same or corresponding parts in each of them.

Referring to Figs. 1 and 2, an internal combustion engine 1 (e.g. a diesel engine) is arranged to drive the rotor of an alternator 10, e.g. via a belt drive to a drive pulley 11 of the alternator. The alternator may have mounting points 12 to enable it to be mounted on or proximate the engine and adjusted to apply the correct tension to the belt. The alternator 10 forms part of an electrical charging system of the engine 1, which may also drive, for example, a vehicle or a generator.

The alternator 10 may be single-phase or three-phase, with a field produced by permanent magnets or windings, and usually also a rectifier and voltage regulator producing a fixed output voltage, although in some alternators the voltage may be controlled by a signal from the engine management unit (ECU).

As illustrated, the alternator may have three terminals. The first, output terminal 13 is conventionally marked “B+” and produces the output current, which for example may be used to charge a starter battery 2 that is used to energise a starter motor of the engine 1, and/or to supply the other loads 3 of the system, typically at a system voltage of 12V or 24V and up to about 150A DC. In this specification, an electrical charging system means a system that produces electrical power which may (but need not) be used to charge a battery.

The second, charging state indicating terminal 14 is conventionally marked “D+” and may carry a current in the range from about 0A to 1A, serving to indicate the operational state of the alternator. It may be connected in use via the ignition switch 4 to a charging lamp 5 with a bypass resistor 6. In use, the terminal 14 passes current to illuminate the charging lamp 5 while the ignition is on but the alternator is not charging, which current ceases to flow, extinguishing the charging lamp 5, when charging begins, typically when the alternator starts to rotate at a speed above about 800RPM. If the alternator is not self-excited then a small voltage may be applied to terminal 14 to excite the alternator at the start of its operation.

The third, tachometer terminal 15 is conventionally marked “W” and produces a speed signal, typically in the form of a pulsed signal with a frequency that varies with the rotational speed of the rotor relative to the stator, typically with a 50% duty cycle and either six or eight pulses per revolution. Referring also to Figs. 3 and 4, the monitoring system comprises a device 20 that is mounted or mountable in use, in or on the alternator 10. As illustrated, the device 20 may be configured as a unit separate from the alternator 10, with the unit being mountable in or on the alternator 10 prior to use. Alternatively, the device 20 may be included in the alternator 10.

The alternator 10 may include a first external casing, e.g. an end cover 16, such as a plastics moulding with ventilation apertures 17 as shown in Fig. 2.

The device 20 may include a second external casing 21, which may be of similar configuration to the first external casing 16 of the alternator 10, so that the first external casing 16 is replaceable by the second external casing 21. The device 20 can be fitted to the alternator by replacing the first external casing 16 with the second external casing 21 (and making any required electrical connections), as shown in Fig. 4.

The device 20 is configured to sense electrical parameters of the electrical charging system, and also to sense at least one ambient condition exogenous to the alternator - which is to say, at least one ambient condition that is not caused by the alternator, but rather, is a defining parameter of the environment in which the alternator operates.

The device 20 includes a timekeeping arrangement 22, and a memory 23 and/or 32. The timekeeping arrangement 22 may be for example a real-time clock, or a signal receiver for receiving an external timekeeping signal, or any other arrangement that allows the device to identify the time and date of the data it collects. The clock may include a crystal oscillator with integrated temperature compensation. The memory 23 may be non-volatile memory and may be arranged as a memory unit, e.g. a flash memory device such as a flash memory card, which may be removable from the device via an external port as illustrated, allowing the stored data to be retrieved simply by removing and replacing the memory unit. The device 20 may include further internal, nonremovable memory 32, which may be both volatile (RAM) and non-volatile (ROM). The device 20 is configured to store, in the memory 23 and/or 32, data representing each of the sensed electrical parameters and the sensed at least one ambient condition, together with a time and date of the data as indicated by the timekeeping arrangement 22, e.g. in the form of a respective timestamp forming part of each data file. Each data item could be timestamped, or a file could be created at regular intervals (e.g. one file per day) containing the data collected on all of the sensed parameters during a defined time period.

The electrical parameters may include any or all of the first, output current at the first, output terminal 13 of the alternator; the second current at the second, charging state indicating terminal 14 of the alternator; the rotational speed of the alternator as represented by the speed signal at the third, tachometer terminal 15 of the alternator; an output voltage of the alternator, which may be measured at output terminal 13; and/or a control voltage of the alternator, which may be measured at terminal 14 or elsewhere.

The device 20 may include one or more sensors or sensing arrangements for measuring the respective electrical parameters and at least one ambient condition, each sensor or sensing arrangement producing signal information representing the measured values. The signal information may be received by a processor 24 of the device, which writes the data to memory. The data may be the signal information, or may be generated by the processor 24 based on the signal information. The processor 24 may be embodied in a microcontroller 25 including processing, memory and other functions as known in the art.

Current at the first and second terminals 13, 14 may be measured by non-contact sensors, e.g. Hall effect sensors 26, so as to ensure that the measurement does not affect the system. Voltage at either or both of the first and second terminals 13, 14, and/or the speed signal at terminal 15, may be measured via sensing conductors 27.

It should be understood that current or voltage at the terminals may be measured by sensors or conductors arranged physically at or proximate the terminals 13, 14, 15, or at at distance from the terminals, e.g. at wires or other internal circuit connections of the alternator. Thus, the device 20 may be arranged so that, when installed, its respective sensors or conductors engage with an internal circuit board or wiring of the alternator 10 rather than with its external terminals.

Additional sensors or conductors or signal inputs may be provided to measure other electrical parameters, e.g. alternator excitation current, battery charge, or system load current demand to be compared with alternator output current.

In practice, it is found that processing the pulsed speed signal at terminal 15 requires a lot of processor power. In order to avoid slowing down the first processor 24, the device may include a dedicated, second processor 28, which is arranged to analyse the pulsed signal to generate the data representing the rotational speed of the alternator 10. The first processor 24 is arranged to receive most or all of the rest of the signal information representing, for example, the first and second currents at terminals 13, 14, and the at least one ambient condition, and to store the data representing those measured parameters in the memory 23. The speed data generated by the second processor 28 may be passed to the first processor 24 to be stored in memory together with the other data, or may be stored in memory by the second processor 28, whichever way is more convenient.

The device 20 may be arranged to calculate a speed of the engine 1 based on the speed signal at terminal 15. This can be done based on the ratio between engine 1 crankshaft revolutions and alternator 10 pulley 11 revolutions, which may be programmed into the device 20 and stored in memory 32. The engine speed may be included in the data written to memory 23 based on the speed signal from alternator terminal 15.

Alternatively or additionally, the device 20 may be arranged to determine and store, in the memory 23, 32, a cumulative running time of the engine 1, perhaps along with the time stamp on each data item. The at least one ambient condition may include any or all of: ambient temperature, ambient barometric pressure, ambient humidity, and/or ambient vibration.

The device 20 may include one or more ambient condition sensors 29 for sensing the or each ambient condition. A respective ambient condition sensor may combine two or more of ambient temperature, pressure, and/or humidity sensing, as known in the art.

The sensors 29 may be configured to sense in a range of values that are distinct from those values that may be produced by the alternator. For example, a vibration sensor may be configured to sense vibration at a range of frequencies distinct from frequencies generated by the alternator in normal operation or in a fault condition, e.g. by bearing failure. Of course, temperature, humidity, and barometric pressure data are unlikely to be affected by alternator operation. The sensors 29 can be mounted inside or outside the casing 21, e.g. behind the ventilation apertures 17.

Optionally, in addition to sensing these exogenous environmental parameters, the device 20 may be equipped with sensors that are configured to sense signal information endogenous to the alternator, e.g. vibration in a frequency range indicative of bearing failure inside the alternator, in which case the data representing these endogenous parameters will also be time stamped and stored together with the data representing the sensed, exogenous ambient conditions and electrical parameters.

Where the at least one ambient condition includes ambient vibration, the sensors 29 may include an accelerometer for sensing the ambient vibration.

The device 20 preferably includes a battery 30 for powering the device, and may further include a charger 31 for charging the battery 30 from the electrical charging system.

A battery 30 is useful to ensure that the device 20 can operate independently of the electrical charging system, and allows the device 20 to sense the system parameters while it is not drawing current from the system, so ensuring accurate measurements. The battery 30 may be replaceable or rechargeable, either from an external power supply (e.g. periodically during maintenance or data upload operations) or from the electrical charging system. In the latter case the device 20 may be arranged to interrupt the charging current to the device battery 30 while sensing one or more system parameters.

In order to conserve battery power, the device 20 may be arranged to transform from an active mode (when it is fully functional) to a sleep mode (when its functions are mostly suspended) when the engine 1 is inactive, and to transform from the sleep mode to the active mode when the engine 1 is active.

To accomplish this, the device 20 may include an acclerometer, which may also function as one of the ambient condition sensors 29. The device 20 may be arranged to transform from the sleep mode to the active mode responsive to a signal from the accelerometer 29 indicating that the engine 1 is active.

The device 20 (e.g. processor 24) may be arranged to analyse the sensed signal information from the sensors or sensing arrangements, or the stored data representing the signal information, to generate diagnostic information for the alternator 10 or the electrical charging system.

In this way the device 20 may act as a predictive monitoring system by analysing the signal information or stored data to identify characteristics that could indicate an impending failure. For example, where the device 20 includes an ambient temperature sensor 29, an unexpected rise in ambient temperature may be an indicator of a developing engine fault. Similarly, an increase in ambient humidity may indicate a burst hose or failed gasket, or, if the engine is driving a vehicle, an adverse operating environment of the vehicle which may result in long term damage to the system.

The device 20 may be arranged to generate the diagnostic information by comparing sensed values with predicted values (i.e. expected values), e.g. as stored in memory 32, e.g. in a look-up table or as an algorithm. Optionally, data files may also be written to memory 32 or 23 from an external resource to update the diagnostic software. For the sensed electrical parameters, predicted values may include, for example, any or all of: expected output current at terminal 13 relative to the sensed speed of the alternator, as indicated e.g. by a look-up table or algorithm; expected current at terminal 14 through the charging lamp 5 relative to the sensed speed of the alternator, as indicated by stored values; and/or expected system voltage between terminal 13 and ground, as represented by stored values, e.g. a nominal value of 14.5V ±0.5V for a 12V system.

For the sensed ambient conditions, predicted values may include stored, static values or values derived from look-up tables or algorithms reflecting how ambient conditions are expected to change with engine operating parameters, e.g. dependent on momentary engine power output, or on how long the engine has been running from start-up. Additional signal inputs may be provided to supply such information to the device 20, e.g. from the ECU.

For sensed electrical parameters and/or ambient conditions, the predicted values may alternatively or additionally be based on previous stored data, so that by comparing new data with previously stored data, the device 20 can detect when the system begins to behave differently. For example, the warmup time of the engine may get longer or shorter, or the engine bay temperature may begin to rise above the average maximum level sensed during previous operational cycles, or the system voltage may begin to fluctuate over a wider value range than previously detected.

The stored data may be analysed and compared over time to identify patterns or trends in the data, which may indicate, for example, how regularly or for how long a period the alternator is overloaded. The device 20 may be configured to extrapolate from the stored data to identify or predict developing fault conditions. The device 20 may perform diagnostic analysis of the sensed data through statistical modelling.

The device 20 may be arranged to generate a warning signal responsive to generating diagnostic information indicative of a sensed or predicted fault condition. The warning signal could be issued via the LED 36 or display screen 37 and/or via the data output interface 38, 39 (further discussed below), e.g. in the form of a message that is sent to a predefined recipient, e.g. a user’s cellphone or a monitoring organisation. Warning signals may enable the user to take corrective action before a system failure occurs. A warning signal could be issued responsive to identifying a developing fault condition, or predicting a future failure, and/or immediately on sensing a critical data value, e.g. an unexpected system voltage.

The device 20 may include a user interface 33, so that the device 20 is operable by a user via the user interface 33, e.g. by pressing control buttons 34.

The user interface 33 may be configured to provide an indication of a condition of the alternator 10 or the electrical charging system, e.g. an LED 35 indicating a healthy system, and another LED 36 indicating a potential fault condition as indicated by the diagnostics information.

The user interface 33 may include a display, e.g. a display screen 37, which may display diagnostic information or just an indication of the status of the system. The screen 37 could be for example a miniature OLED screen. As illustrated, the display or display screen 37 may be configured, in use, to form part of an external casing 21 of the alternator 10.

The device 20 may include a data output interface 38, 39, which may include a wireless transmitter 38 and/or a connector 39 for mechanically connecting the device 20 to an external apparatus (e.g. a compatible diagnostics unit or a laptop or smartphone) which may download the stored data from the memory 23 or 32. The wireless transmitter 38 may be arranged to communicate via a cellular wireless communications network, e.g. to the cloud, e.g. as part of a telematics system, and/or via near field communication to a proximate device. The network may be a Narrow Band Internet of Things, which is to say, it may provide low power cellular point to point communication between devices, allowing the device 20 to communicate with a target recipient via any other devices that happen to be within range.

The device 20 may be operable to communicate, via the data output interface 38, 39, at least one of the stored data, and diagnostic information derived from the stored data. The device may support graphic data presentation via an app running on a user’s device.

The data output interface may support communication over a Controller Area Network (e.g. via a CAN harness) as known in the art for transmitting data between devices in an automotive environment.

In these ways the measured data may be used to monitor and report on the status of the charging system. The data may be stored in memory 23 over an extended period (e.g. a month or more) or only temporarily in memory 23 or 32 before it is transmitted to a remote device (in which case removable memory 23 need not be present). The memory 23 may be wiped regularly, e.g. on a rolling basis after data is uploaded to a remote device or when the memory unit is removed and replaced.

Industrial

The novel device is not intended principally to detect alternator faults such as bearing failure (although it may also detect such data), but rather, to detect ambient conditions exogenous to the alternator 10 and to log that data together with electrical data sensed at the same time.

The time and date stamp allows the two data streams to be correlated to identify any environmental factors that may have contributed to an alternator malfunction as indicated by the sensed electrical data.

By way of example, an alternator 10 will incorporate various electrical components that are operable within a defined range of temperature, pressure or humidity, and also mechanical components or circuit elements (e.g. wiring, electrical connectors, solder joints, component casings) that may be susceptible of failure under certain abnormal conditions of vibration.

By identifying the ambient conditions in which the alternator 10 is operating, the novel device 20 makes it possible to correlate electrical malfunction with sensed ambient conditions that may have contributed to the malfunction. The test engineer can simply pull from the memory 23, 32 data representing the ambient operating conditions of the alternator 10 over a time period leading up to the development of a fault condition, and analyse that data to find possible reasons why the component failed.

By mounting the device 20 including ambient condition sensors 29 on the alternator 10, it is achieved that the sensed ambient conditions are always those to which the alternator 10 is exposed, even if such conditions are highly localised.

This can be significant for example in many vehicular applications where the alternator 10 is mounted on or proximate the engine 1 in an enclosed space, e.g. under the engine cover, and so is subject to ambient conditions that may exist only in that one location within the space.

Ambient conditions may reflect for example the pattern of airflow through the under-bonnet space, the distribution of heat emitting engine exhaust and other elements within that space, fluid emissions from the engine 1 resulting in localised temperature, humidity or pressure effects, or local vibration effects that can vary substantially in amplitude over a short distance depending on variations in the stiffness and resonant frequencies of the supporting structures.

The data can be used by test or maintenance personnel to reduce the time required for troubleshooting and help to identify the root cause of alternator failure, and to implement preventative or proactive fault detection.

From the perspective of the alternator manufacturer, the data collected by the novel device 20 can be used to identify key vulnerabilities in the alternator components to out-of-specification operating conditions, and so to improve alternator design.

From the perspective of the vehicle operator, the device 20 serves not only to monitor the alternator 10, but also to monitor engine usage and to provide an early warning of abnormal operating conditions proximate the alternator 10 that may indicate a fault in the engine 1 or related components.

In embodiments, the novel device 20 also enables remote monitoring (telematics) for vehicles that are built without that functionality, making it possible to integrate purely mechanical vehicles into a remote monitoring and maintenance program. In summary, in embodiments, a device 20 is mounted in or on an alternator 10 driven by an internal combustion engine 1 to detect electrical parameters of the electrical charging system and ambient conditions exogenous to the alternator 10, e.g. ambient temperature and vibration in the engine compartment. The sensed data is timestamped, stored and analysed by correlating sensed ambient conditions with electrical system data to provide monitoring and predictive diagnostics on the engine 1 and electrical system.

Many further adaptations are possible within the scope of the claims. In the claims, reference numerals and characters are provided in parentheses, purely for ease of reference, and are not to be construed as limiting features.