GB2548594B

GB2548594B - Portable test equipment

Info

Publication number: GB2548594B
Application number: GB1604870.4A
Authority: GB
Inventors: Kumar Ashok; Treharne Jason
Original assignee: Jaguar Land Rover Ltd
Current assignee: Jaguar Land Rover Ltd
Priority date: 2016-03-22
Filing date: 2016-03-22
Publication date: 2019-06-12
Anticipated expiration: 2036-03-22
Also published as: GB201604870D0; GB2548594A

Description

PORTABLE TEST EQUIPMENT

TECHNICAL FIELD

The present invention relates to a diagnostics apparatus for a motor vehicle and to a method of diagnosing a feature associated with motor vehicle operation such as a fault. Aspects of the invention relate to a motor vehicle, to a diagnostics apparatus for a motor vehicle and to a method of diagnosing a motor vehicle fault.

BACKGROUND

It is known to provide apparatus for diagnosing a feature associated with motor vehicle operation, such as a feature associated with operation of one or more circuits or components, for example a fault, in the form of an inductive current clamp meter. The clamp meter has a pair of jaws that are arranged to open to allow them to be clamped around an electrical conductor without requiring interruption of current flow through the conductor. The amount of alternating current flowing through the conductor is measured by measuring the amount of current induced in the jaws by the alternating magnetic field associated with the current. A problem with known diagnostics apparatus is that the jaws of the clamp meter must substantially surround the conductor in order to enable a reading of current flow to be made. Furthermore, current clamp meters are generally suited primarily to the measurement of alternating currents.

It is also known to measure the amount of current flowing in a motor vehicle circuit by plugging a current meter into an electrical circuit in place of a fuse element in the fusebox such that the meter is connected in the circuit in series with one or more other components. This method suffers the disadvantage that the flow of electrical current in the circuit is interrupted when the fuse element is removed.

It is also known to provide motor vehicle fuse elements having electrical current measuring devices integrated therein. The fuse elements may be configured to provide an output indicative of the amount of current flowing therethrough at a given moment in time.

It is an aim of the present invention to address one or more disadvantages associated with the prior art.

SUMMARY OF THE INVENTION

Embodiments of the invention may be understood with reference to the appended claims.

Aspects of the present invention provide an apparatus, a vehicle and a method.

There is described herein a motor vehicle diagnostics apparatus comprising: a clamp portion for attachment to a motor vehicle circuit protection element installed in a motor vehicle in an electrical circuit of the vehicle, the clamp portion comprising gripping means configured to allow releasable attachment of the clamp portion to the protection element whilst the protection element is in-situ; and means for providing an output indicative of at least one electrical characteristic of the protection element whilst the clamp portion is attached to the protection element.

The circuit protection element may comprise a fuse element comprising a fusible link. Alternatively the circuit protection element may comprise a resettable circuit breaker element.

In one aspect of the invention for which protection is sought there is provided a motor vehicle diagnostics apparatus comprising: a clamp portion for attachment to a motor vehicle fuse element installed in an electrical circuit of the vehicle, the clamp portion comprising gripping means configured to allow in-situ attachment to and detachment from the fuse element, whilst the fuse element is carrying an electrical current; and means for providing an electrical signal indicative of at least one electrical characteristic of the fuse element when the clamp portion is attached to the fuse element, wherein the clamp portion comprises a magnetic field sensor, located within an extended tip portion of the gripping means, configured to generate an electrical signal responsive to a flow of current in the fuse element.

The fuse element may be provided in a fusebox of a motor vehicle.

Embodiments of the present invention have the advantage over known diagnostic apparatus that the signal indicative of the least one electrical characteristic may be provided without requiring interruption of current flow through the fuse element, for example by removal of the fuse element from the fusebox. That is, it is not necessary to remove the fuse element, for example in order to plug a current meter into the electrical circuit in place of the fuse, in order to obtain the signal indicative of the at least one electrical characteristic. Nor is it necessary to provide a fuse element having an electrical current measuring device provided therein.

The electrical signal may be generated by induction of current in the sensor due to the magnetic field generated by the flow of current in the fuse element.

Optionally, the magnetic field sensor comprises at least one Hall effect sensor.

Optionally, the clamp portion further comprises an amplifier portion for amplifying the electrical signal generated by the magnetic field sensor.

The signal indicative of at least one electrical characteristic may be provided by an electrode that is connected substantially directly to the electrode of the fuse element.

It is to be understood that knowledge of the electrical potential at a fuse element in an electrical circuit may enable the amount of current flowing through the fuse element to be determined. For example, the fuse element may be connected in a circuit such that the fuse element assumes a predetermined electrical potential other than earth potential when the circuit is closed and current flows in the circuit, for example when a door is in a predetermined position, such as an open condition.

Optionally, the apparatus is configured to log data in respect of the electrical signal indicative of at least one electrical characteristic in a memory thereof.

For example, the apparatus may log data in respect of the electrical signal indicative of at least one electrical characteristic in a memory, for example data corresponding to a value of the electrical signal, as a function of time. For example the apparatus may sample the value of the signal at repeated intervals and store the sampled values as data corresponding to the value of the electrical signal.

Optionally, the apparatus further comprises means for displaying data responsive to the electrical signal indicative of at least one electrical characteristic.

Optionally, the apparatus comprises a computing device, the computing device being configured to receive the electrical signal indicative of at least one electrical characteristic, and to provide an output in dependence on the signal.

Optionally, the apparatus is configured to provide an output indicative whether the electrical signal corresponds to an expected signal by reference to stored data in respect of an expected signal.

For example, the computing device may determine whether the amount of current flowing in the fuse element corresponds to an expected amount, and/or whether a waveform of current flowing in the fuse element corresponds to an expected waveform. Alternatively, where electrical potential is measured, the computing device may determine whether the electrical potential corresponds to an expected value of potential, and/or whether a variation in electrical potential corresponds to an expected variation.

Optionally, the apparatus is operable to provide a visual indication of a correspondence between a form of the electrical signal indicative of at least one electrical characteristic and an expected form of the signal.

Optionally, the apparatus is operable to provide a visual or audible indication whether a value of the at least one characteristic of which the electrical signal is indicative is within a prescribed range of values of that characteristic.

Optionally, the apparatus is operable to provide the visual or audible indication by reference to the data in respect of one or more expected characteristics.

Optionally, the gripping means is shaped to conform at least in part to an outer shape of the fuse element.

Optionally, the apparatus is coupled to a fuse element of a motor vehicle.

The apparatus may be a portable apparatus. The clamp portion may be arranged to be attached to a fuse element by a user by hand. The computing device may be provided in the form of a handheld device, a laptop computing device, or computing device provided on a movable cart. Optionally the computing device may be part of a substantially fixed installation, the clamp portion being tethered to the computing device by means of the cable.

Optionally, the clamp portion may be arranged to communicate wirelessly with the computing device, for example by means of a Bluetooth (RTM) connection.

In some embodiments the computing device may be integrated into the clamp portion to form a single, handheld diagnostics apparatus.

In one aspect of the invention for which protection is sought there is provided a vehicle comprising apparatus according to any preceding claim coupled to a fuse element installed in an electrical circuit of the vehicle.

In an aspect of the invention for which protection is sought there is provided a method of diagnosing a fault associated with a motor vehicle by means of diagnostics apparatus comprising: connecting a clamp portion of a diagnostics apparatus to a fuse element installed in an electrical circuit of the vehicle, whereby gripping means of the clamp portion attaches the clamp portion to the fuse element in-situ, whilst the fuse element is carrying an electrical current; and providing an electrical signal indicative of at least one electrical characteristic of the fuse element when the clamp portion is attached to the fuse element; wherein the clamp portion comprises a magnetic field sensor, located within an extended tip portion of the gripping means, configured to generate an electrical signal responsive to a flow of current in the fuse element.

The method may comprise providing the electrical signal to a computing device, and providing an output from the computing device in dependence on the signal.

There is also described herein a motor vehicle diagnostics apparatus comprising: a hand-held magnetic field sensor device comprising at least one sensor, the device being configured to generate an electrical signal responsive to a flow of current in a motor vehicle electrical circuit; and means for outputting the electrical signal generated by the magnetic field sensor device.

The sensor may be or comprise a Hall effect sensor. Other sensors may be useful in some embodiments.

There is further described herein a motor vehicle diagnostics apparatus comprising: a hand-held magnetic field sensor device comprising at least one Hall effect sensor, the device being configured to generate an electrical signal responsive to a magnetic field generated by a flow of current in a motor vehicle electrical circuit; and means for outputting the electrical signal generated by the magnetic field sensor device.

The apparatus may comprise a hand-held housing comprising the magnetic field sensor device.

Optionally, the magnetic field sensor device further comprises an amplifier portion for amplifying a signal generated by the Hall effect sensor to generate the electrical signal output by the device.

Optionally, the apparatus comprises a computing device configured to receive the electrical signal output by the sensor device, the computing device being arranged to provide an output in dependence on the signal.

Optionally, the apparatus is configured to provide an output indicative whether the electrical signal output by the sensor device corresponds to an expected signal by reference to stored data in respect of an expected signal.

For example, the computing device may determine whether the amount of current flowing in the motor vehicle electrical circuit corresponds to an expected amount, and/or whether a waveform of current flowing in the motor vehicle electrical circuit corresponds to an expected waveform. Alternatively, where electrical potential is measured, the computing device may determine whether the electrical potential corresponds to an expected value of potential, and/or whether a variation in electrical potential corresponds to an expected variation.

Optionally, the apparatus is operable to provide a visual indication of a correspondence between a form of the electrical signal output by the sensor device and an expected form of the signal.

Optionally, the apparatus is configured to provide a visual or audible indication whether at least one characteristic of current flow in the motor vehicle electrical circuit corresponds sufficiently to predetermined, stored data in respect of current flow in the electrical circuit.

The predetermined stored data may be predetermined stored data in respect of current flow in the electrical circuit when the circuit is correctly functioning.

Optionally, the apparatus is configured to provide a visual or audible indication whether at least one characteristic of current flow in the motor vehicle electrical circuit corresponds sufficiently to one or more predetermined, stored datasets in respect of current flow in the electrical circuit when the circuit has one or more predetermined faults.

The characteristic may for example be a frequency of alternating current flow and/or amplitude of current flow in the circuit. Other characteristics may be useful such as a variation as a function of time of the amplitude and/or frequency of current flow in the circuit. The computing device may be configured to analyse the amplitude of currents of one or more frequencies, for example a current analysis within a predetermined spectral range. It is to be understood that a correctly functioning circuit or electrical component may generate an electromagnetic field due to current flow that has certain definable characteristics that change as the circuit or component ages, or when a fault occurs. The computing device may be configured to analyse the electrical signal output by the sensor and determine the amplitude of components of the signal of respective frequencies. The relative amplitudes as a function of frequency may be considered to provide a characteristic ‘fingerprint’ or ‘signature’ of the circuit or component. The computing device may then determine whether the signature corresponds to a correctly functioning circuit or component by comparison with stored data. In some embodiments the computing device may determine whether the signature corresponds to one of a predetermined group of one or more stored signatures characteristic of known, predetermined faults. The computing device may be configured to provide an output indicative of the identity of the known signature that the observed signature corresponds to. Thus, the computing device may provide an output indicative that the circuit or component appears to be correctly functioning, or that the circuit or component does not appear to be functioning correctly. In the latter case, the computing device may provide an indication of the identity of the fault that the computing device considers the observed signature corresponds to.

For example, the computing device may store predetermined data corresponding to the expected signature generated when the sensor device is held against a door of a vehicle when a correctly functioning electrical door latch is actuated from an open condition to the closed condition. That is, the computing device may store data indicative of the variation, as a function of time, of the relative amplitudes of electrical signals of different respective frequencies that are generated in the sensor device when the electrical door latch is actuated from the open to the closed condition. When the sensor device is held against a door of a subject vehicle, the computing device may capture data indicative of the variation, as a function of time, of the relative amplitudes of electrical signals of different respective frequencies that are generated in the sensor device when the electrical door latch is actuated from the open to the closed condition. The computing device may then compare this captured data with the stored, predetermined data corresponding to a correctly functioning door latch and provide an output in dependence on the comparison.

If the data is found to correspond sufficiently, the computing device may provide an output indicative that the door latch is considered to be correctly functioning.

If the data is found not to correspond sufficiently, the computing device may provide an output indicative that the door latch is not considered to be correctly functioning. In this case, in some embodiments the computing device may compare the captured data with stored, predetermined data corresponding to a door latch that is not correctly functioning and provide an output in dependence on the comparison. The computing device may for example be provided with predetermined data corresponding to (1) a door latch that has a correctly functioning electrical solenoid actuator but which is not closing when an attempt is made to actuate it due to jamming of the lock, and (2) a door latch that is not closing when an attempt is made to actuate it due to a failing electrical solenoid actuator. It is to be understood that the respective signatures generated when the sensor device is held against a door of a vehicle having fault (1) and a door having fault (2) may be sufficiently different to enable a distinction to be made between the presence of fault (1) and the presence of fault (2) when diagnosing faults in another subject vehicle.

Optionally, the apparatus is configured to store data in respect of the form of the electrical signal output by the sensor device.

For example, the apparatus may store or ‘log’ data corresponding to values of the electrical signal as a function of time. For example the apparatus may sample the value of the signal at repeated intervals and store the sampled values as data corresponding to the value of the electrical signal. The apparatus may store data indicative of the spectral variation in amplitude of the signal as a function of time. For example, the apparatus may apply a Fourier transform function to the captured data to generate spectral information.

These features have the advantage over known diagnostic apparatus that an electrical signal responsive to a flow of current in a motor vehicle electrical circuit may be generated without requiring interruption of current flow through the motor vehicle circuit. For example it is not necessary to interrupt the circuit to couple a current meter into the electrical circuit. Some embodiments of the present invention enable diagnosis of a fault in a motor vehicle electrical circuit without a requirement to remove a component from the vehicle for testing, such as a door latch actuator.

Optionally, the housing has a substantially flat outer surface portion configured for placing in abutment with a motor vehicle panel, wherein the sensor portion may be provided a predetermined distance from the panel.

It is to be understood that the sensor may be provided within the housing in a predetermined spatial orientation with respect to the flat outer surface portion.

The sensor may be a multi-axis sensor such as a two- or three-axis sensor such that measurements of magnetic field may be made independently of the orientation of the sensor with respect to the field.

The apparatus may be a portable apparatus. The hand-held magnetic field sensor device may be arranged to be attached to a fuse element by a user by hand. The computing device may be provided in the form of a handheld device, a laptop computing device, or computing device provided on a movable cart. Optionally the computing device may be part of a substantially fixed installation, the hand-held magnetic field sensor device being tethered to the computing device by means of the cable. Optionally, the clamp portion may be arranged to communicate wirelessly with the computing device, for example by means of a Bluetooth (RTM) connection.

The computing device may be integrated into the hand-held magnetic field sensor device to form a single, handheld diagnostics apparatus.

There is further described herein method of diagnosing a fault in a motor vehicle by means of a diagnostics apparatus comprising: providing a hand-held magnetic field sensor device comprising at least one Hall effect sensor adjacent a motor vehicle electrical circuit and causing an electrical signal to be generated by the sensor device in response to a magnetic field generated by a flow of current in the motor vehicle electrical circuit; and outputting an electrical signal generated by the magnetic field sensor device.

These features of the invention have the advantage that the apparatus is able to monitor signals associated with a motor vehicle control system to enable a user to determine whether the control system is functioning correctly. For example a user may be able to determine an origin of a fault or other feature associated with a vehicle.

The apparatus may be operable to provide a visual indication of a correspondence between a form of a signal detected by the diagnostics unit and an expected form of the signal.

The visual indication may be in the form of a graphical plot of the signal as a function of time. An expected form of the signal may be superimposed on the graphical plot in some embodiments.

The apparatus may be operable to provide a visual or audible indication whether a value of at least one characteristic of a detected signal is within a prescribed range of values of that characteristic.

This feature has the advantage that a user can determine when a signal transmitted through a vehicle circuit is within the prescribed range. This can assist a user in determining the location of a fault in the circuit. For example, a user can manipulate (e.g. ‘wiggle’) cabling forming part of the circuit and monitor the value of at least one characteristic of a detected signal. If the characteristic is outside of the prescribed range of values the apparatus provides a visual or audible alert. Thus, for example if a signal is expected to have a value in the range +/- 5V the apparatus may be configured to provide a visual or audible alert if the value rises above 5V or falls below -5V. Similarly, if a signal is expected to have a value of at least 10V, the apparatus may be configured to provide a visual or audible alert if the value falls below 10V. Other arrangements are also useful.

The apparatus may be operable to provide the visual or audible indication by reference to the data in respect of expected signals.

Within the scope of the claims it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying figures in which: FIGURE 1 is a schematic illustration of a clamp portion of a motor vehicle diagnostics apparatus; FIGURE 2 shows (a) a sensor device in the form of a printed circuit board carrying a Hall effect sensor and associated components, and (b) the clamp portion of FIG. 1 in cross-sectional side view; FIGURE 3 shows the sensor device of FIG. 2(a) in plan view; FIGURE 4 shows a motor vehicle diagnostics apparatus according to a further embodiment of the invention; and FIGURE 5 shows (a) a proximal end of a clamp portion according to an embodiment of the present invention as viewed in cross-section along line A-A in the direction of arrows A shown in FIG. 1, and (b) an upper end of a known blade-type fuse element.

DETAILED DESCRIPTION

Embodiments of the present invention are directed to providing a diagnostics apparatus for diagnosing a fault with a motor vehicle. FIG. 1(a) is a schematic 3D illustration of a sensor module in the form of a clamp portion 110 of an apparatus 105 shown in FIG. 1(b) for diagnosing a motor vehicle fault. The clamp portion 110 has first and second jaws 111, 112 respectively that are pivotally connected by means of a hinge 113 so as to enable the clamp portion 110 to be releasably clamped to a known fuse element 10. The jaws 111, 112 are resiliently biased by means of a spring element to a closed condition in which proximal free ends 111B, 112B that grip the fuse element 10 assume a closed condition in which they are substantially in abutment when no fuse element 10 is present there between.

The second jaw is provided with an extended tip portion 112A that is arranged, when the clamp portion is gripping a fuse, to lie against a major side face of the fuse element 10. Packaged within the second jaw 112 of the clamp portion 110 is a sensor portion 120 of the clamp portion 110 illustrated in FIG. 2(a) and FIG. 3. The sensor portion 120 is in the form of a printed circuit board (PCB) 121 that bears components for generating an electrical signal in response to exposure of the sensor portion 120 to a magnetic field generated by current flow in an external electrical circuit. In the embodiment of FIG. 2(a) and FIG. 3 the components include a Hall effect sensor 122 at one end of the PCB 121 for sensing a magnetic field, an operational amplifier 124 and additional components such as resistors and capacitors. In the present embodiment the sensor portion 120 is configured to output an analogue signal in response to a magnetic field detected by the sensor 122. In some alternative embodiments, the sensor portion 120 may be configured to output a digital signal.

The clamp portion 110 is arranged such that the PCB 121 fits within second jaw 112 with the Hall effect sensor 122 located within the tip portion 112A. Accordingly, when a fuse is clamped or gripped by the first and second jaws 111, 112, the sensor 122 lies directly above a major side face of the fuse element 10 with respect to the orientation of the clamp portion 110 in FIG. 1(a). The sensor 122 is therefore in relatively close proximity to a fusible link within the fuse element 10 that bridges between first and second connector electrodes 10E1, 10E2 of the fuse element 10.

The clamp portion 110 is arranged such that, when a fuse element 10 is gripped by the jaws 111, 112, a shoulder portion 112S of the proximal free end 112B of the second jaw 112 and a shoulder portion 111S of the proximal free end 111B of the first jaw 111 abuts an upper surface of the fuse element 10. A tip portion 111A of the first jaw 111 at the proximal end 111B is provided with a recess that engages a lip 10L of the fuse element 10 that protrudes laterally outwardly around the upper surface of the fuse element 10. A corresponding recess is provided in the tip portion 112A of the second jaw 112. Thus, the clamp portion 110 may be clamped to a fuse element 10 by a user such that a user is not required to hold the clamp portion 10 in place whilst an electrical measurement is made.

The sensor portion 120 is configured such that an electrical signal generated in response to the presence of a magnetic field is amplified and output via cable 150C to a computing device 160. In the embodiment of FIG. 1 the computing device 160 receives the analogue signal output by the sensor portion 120 via an analogue to digital converter (ADC) interface that converts the analogue signal to a digital signal. The computing device stores data indicative of the variation in detected magnetic field strength as a function of time.

In the present embodiment, the computing device is configured to perform a spectral analysis of the signal received for comparison with predetermined stored data. The stored data comprises data in respect of corresponding measurements of fuse elements 10 installed in vehicles having (1) a correctly functioning circuit in which the fuse element 10 is installed and (2) circuits with known malfunctions.

The computing device 160 is configured to permit a user to indicate the identity of the fuse element under test, for example ‘door latch circuit’. The computing device 160 then monitors the electrical signal received from the clamp portion 110 whilst the circuit is subject to one or more predetermined sequences of circuit functions. In the case of a door latch circuit one predetermined sequence may be the opening and closing of a given door latch.

The computing device 160 repeatedly performs a spectral analysis of the signal detected by the sensor portion 120 whilst the predetermined sequence is performed and compares the analysis with the predetermined stored data. In the present embodiment the spectral analysis includes application of a Fourier transform function to the captured data to generate spectral information. In the event the computing device 160 is able to find a sufficiently high correspondence between the predetermined data corresponding to a correctly functioning circuit the device 160 outputs a signal indicating the signal corresponds to a correctly functioning circuit. In the event the computing device 160 finds a sufficient correspondence with predetermined data corresponding to a certain fault, the device 160 outputs a signal indicative of the nature of the fault.

The computing device 160 is also configured to provide an indication of the amount of AC or DC current flowing through the fuse element 10 at a given moment in time, again based on the magnetic field generated by the current. Thus, the apparatus 105 may be used to perform standard electrical measurements without any disturbance to components of the circuit under test. The apparatus 105 may be referred to as in-situ diagnostics apparatus because it may be used to monitor current flow in circuits whilst the circuits are functioning. FIG. 4 shows an alternative sensor module 210 for measuring current flow in a circuit. Like features of the sensor module 210 of FIG. 4 to the clamp portion 110 of FIG. 1(b) are shown with like reference signs incremented by 100.

The module 210 is configured to be attached to the computing device 160 shown in FIG. 1(b) by means of cable 250C in place of the clamp portion 110 of the embodiment of FIG. 1, and to be used in a similar way except that the module 210 is not configured to be clamped to a component.

Instead, the module 210 adapted to be held by a user in proximity to a portion of a circuit or a circuit component that is to be subject to testing. The module 210 has a housing 21 OH that encases a sensor portion 120 of the type shown in FIG. 2(a) and FIG. 3. The housing 21 OH holds the sensor portion 120 in close proximity to a wall 210HW of the housing 21 OH defining a major external surface 21 OHS of the housing 21 OH. The module 210 is configured to be placed with the major external surface 21 OHS in contact with a portion of a vehicle or other item to be tested, so that the sensor portion 120 is provided in relatively close proximity to the component or circuit to be tested. For example, in the case that the module 210 is to be used to test the operation of a door latch, the module 210 may be placed with the major external surface 21 OHS against an exterior or interior door panel. In the embodiment of FIG. 4 the major external surface 21 OHS is provided with a layer of compliant material, in the present embodiment a layer of soft fabric, to reduce the risk of scratching or other damage to a surface such as a vehicle door panel when in contact therewith. The module 210 may be referred to loosely as a ‘stethoscope’ in that it is placed in proximity to a component to be tested and ‘listens’ for the presence of electromagnetic fields detectable by the Hall effect sensor.

It is to be understood that the signal generated by the sensor 122 may be subject to signal processing in an attempt to reduce electromagnetic noise and extract components of the signal associated with the circuit under test. In some embodiments, a signal associated with operation of the circuit under test may be provided to the apparatus 105, for example to the computing device 160, to assist the computing device 160 in distinguishing between detected signals generated by the circuit under test and signals from extraneous sources. The computing device may perform some such signal processing and extraction in software, for example using suitable filters and algorithms. FIG. 5(a) illustrates a further embodiment of the present invention, based on the clamp portion 110 of FIG. 1. FIG. 5(a) shows a cross-section of the clamp portion 110 at the position of line A-A as viewed in the direction of arrows A.

In the embodiment of FIG. 5(a), the shoulder portion 112S of the proximal free end 112B of the second jaw 112 is provided with a pair of electrodes 110E1, 110E2 that protrude outwardly towards a fuse element 10 gripped by the clamp portion 110. The electrodes 110E1, 110E2 are arranged to contact a corresponding pair of electrodes 10C1, 10C2 that are exposed at or near the upper surface 10S of the fuse element 10. The electrodes 10C2, 10C2 are typically extensions of the first and second connector electrodes 10E1, 10E2 of the fuse element 10. The electrodes 110E1, 110E2 are coupled to the PCB 121 of the sensor portion 120. The sensor portion 120 is configured to measure an electrical potential of the electrodes 110E1, 110E2 and to feed a signal to the computing device 160 via cable 150C indicative of the potential of each electrode 110E1, 110E2 with respect to ground. In some embodiments the sensor portion 120 may, in addition or instead, feed a signal indicative of the potential difference between the electrodes 110E1, 110E2 to the computing device 160. In some embodiments, the apparatus 105 may calculate the amount of current flowing through the fuse element 10 (and therefore the portion of the circuit in which the fuse element 10 is connected) based on the potential difference between the electrodes 110E1, 110E2. In some embodiments, the clamp portion 110 is not provided with a sensor portion having a magnetic field sensor. Rather, the means for providing an electrical signal indicative of at least one electrical characteristic of the fuse element when the clamp portion is attached to the fuse element is provided by one or more electrodes 10E1, 10E2 of the clamp portion 110 that are arranged to contact one or more corresponding electrodes 10C1, 10C2 of the fuse element 10. Whilst two electrodes 110E1, 110E2 are shown in the embodiment of FIG. 5, in some embodiments only one electrode 110E1 is provided. More than two electrodes may be provided in some embodiments.

It is to be understood that some embodiments of the present invention may be arranged to operate in conjunction with an existing diagnostics system, for example the Jaguar Land Rover (JLR) symptom driven diagnostics (SDD) system. The computing device 160 may be provided by the existing system such as the JLR SDD system, subject to appropriate reprogramming to enable the SDD system to process signals provided by the clamp portion 110 or sensor module 210.

In some embodiments the clamp portion 110 or module 210 may have the computing device 160 integrated therewith to form a single packaged handheld unit. In some alternative embodiments the clamp portion 110 or module 210 may be configured to communicate wirelessly with a computing device 160. In some embodiments a kit of parts may be provided with a clamp portion 110, a module 210 and a computing device 160. The computing device 160 may be arranged to communicate with the clamp portion 110 and/or module 210, as required.

Embodiments of the present invention provide an efficient, cost effective means for understanding one or more features associated with motor vehicle operation such as a fault or other feature.

Claims

CLAIMS:

1. A motor vehicle diagnostics apparatus comprising: a clamp portion (110) for attachment to a motor vehicle fuse element (10) installed in an electrical circuit of the vehicle, the clamp portion (110) comprising gripping means (111, 112) configured to allow in-situ attachment to and detachment from the fuse element (10), whilst the fuse element (10) is carrying an electrical current; and means for providing an electrical signal indicative of at least one electrical characteristic of the fuse element when the clamp portion (110) is attached to the fuse element (10), wherein the clamp portion comprises a magnetic field sensor, located within an extended tip portion (112A) of the gripping means (112), configured to generate an electrical signal responsive to a flow of current in the fuse element.

2. Apparatus according to claim 1 wherein the magnetic field sensor comprises at least one Hall effect sensor.

3. Apparatus according to claim 1 or claim 2 wherein the clamp portion further comprises an amplifier portion for amplifying the electrical signal generated by the magnetic field sensor.

4. Apparatus according to any preceding claim configured to log data in respect of the electrical signal indicative of at least one electrical characteristic in a memory thereof.

5. Apparatus according to any preceding claim further comprising means for displaying data responsive to the electrical signal indicative of at least one electrical characteristic.

6. Apparatus according to any preceding claim comprising a computing device, the computing device being configured to receive the electrical signal indicative of at least one electrical characteristic, and to provide an output in dependence on the signal.

7. Apparatus according to claim 6 configured to provide an output indicative whether the electrical signal corresponds to an expected signal by reference to stored data in respect of an expected signal.

8. Apparatus according to any preceding claim operable to provide a visual indication of a correspondence between a form of the electrical signal indicative of at least one electrical characteristic and an expected form of the signal.

9. Apparatus according to any preceding claim operable to provide a visual or audible indication whether a value of the at least one characteristic of which the electrical signal is indicative is within a prescribed range of values of that characteristic.

10. Apparatus according to claim 9 operable to provide the visual or audible indication by reference to the data in respect of one or more expected characteristics.

11. Apparatus according to any preceding claim wherein the gripping means is shaped to conform at least in part to an outer shape of the fuse element.

12. Apparatus according to any preceding claim coupled to a fuse element of a motor vehicle.

13. A vehicle comprising apparatus according to any preceding claim coupled to a fuse element installed in an electrical circuit of the vehicle.

14. A method of diagnosing a fault associated with a motor vehicle by means of diagnostics apparatus comprising: connecting a clamp portion of a diagnostics apparatus to a fuse element installed in an electrical circuit of the vehicle, whereby gripping means of the clamp portion attaches the clamp portion to the fuse element in-situ, whilst the fuse element is carrying an electrical current; and providing an electrical signal indicative of at least one electrical characteristic of the fuse element when the clamp portion is attached to the fuse element; wherein the clamp portion comprises a magnetic field sensor, located within an extended tip portion of the gripping means, configured to generate an electrical signal responsive to a flow of current in the fuse element.

15. A method according to claim 14 comprising further comprising providing the electrical signal to a computing device, and providing an output from the computing device in dependence on the signal.