WO2005034047A1

WO2005034047A1 - System and method for diagnosing an automotive vehicle

Info

Publication number: WO2005034047A1
Application number: PCT/NL2003/000678
Authority: WO
Inventors: Robert Johannes Hoevenaar; Carel Christiaan Anthoni
Original assignee: Snap-On Technologies, Inc.
Priority date: 2003-10-03
Filing date: 2003-10-03
Publication date: 2005-04-14
Also published as: AU2003269725A1; EP1668601A1

Abstract

A system for diagnosing an automotive vehicle comprising sensing means for generating a sensing signal representative of a physical quantity of the automotive vehicle and a diagnostic testing device comprising a sensing input for receiving the sensing signal from a dedicated sensor device for cooperation with the testing device. The sensing means comprise a communication unit, operationally connectable to a diagnostic data communication port of the vehicle for communicating diagnostic data with the automotive vehicle via a diagnostic data communication link and a sensing signal generation unit for converting a part of the diagnostic data into a signal compatible with the sensing input of the diagnostic testing device in this manner, and existing diagnostic testing device, such as a vehicle exhaust emissions tester can be used with any type of vehicle equipped with a diagnostic data communication port, while avoiding a need to establish operational connections between one or more sensing devices and the vehicle.

Description

Title: System and method for diagnosing an automotive vehicle.

The invention relates to a system for diagnosing an automotive vehicle, the system comprising sensing means for generating a sensing signal representative of a physical quantity of the automotive vehicle and a diagnostic testing device comprising a sensing input for receiving the sensing signal from a dedicated sensor device for cooperation with the testing device. Further, the invention relates to a method for diagnosing an automotive vehicle, the method comprising generating a sensing signal representative of a physical quantity of the automotive vehicle; and receiving the sensing signal by a diagnostic testing device comprising a sensing input for receiving the sensing signal from a dedicated sensor device for cooperation with the testing device. Such a system, and corresponding method, is known and applied in e.g. service, such as maintenance and diagnostics of automotive vehicles for decades. This diagnostic testing device, such as an exhaust emissions tester, an engine tester, a dynamometer, a brake tester, or any other suitable diagnostic testing device, is provided with signals generated by dedicated sensor devices, such as engine temperature sensors, exhaust gas sensors, ignition pulse sensors from which e.g. an angular speed or a number of revolutions per time unit of the engine is derived, etc. These dedicated sensor devices are mainly analogue, however, digital or partly digital implementations are currently seen also. The sensor device provides a sensing signal to the diagnostic testing device which represents the quantity sensed by the sensor device, the diagnostic testing device deriving a diagnostic value from information contained in one or more sensing signals generated by a sensor device. In an example, the diagnostic testing device comprises an exhaust tester, the sensor devices comprising an exhaust gas probe for monitoring a composition of exhaust gases of the vehicle, a temperature sensor for monitoring a vehicle engine temperature (e.g. a temperature of a cooling fluid or a temperature of oil in the engine) , and a probe which is connectable to an ignition cable for providing a signal representative of ignition pulses supplied to the engine or a cylinder thereof. The diagnostic testing device in this example comprises respective sensing inputs for receiving a respective sensing signal from each of the sensor devices. A problem associated with the testing device and method described above is that it is difficult with modern vehicles to connect the sensor device (s) in a suitable, operational manner to the vehicle. In earlier days parts of e.g. an engine of a vehicle were easily accessible, and consequently the sensor device could easily be operationally connected to a suitable part or element of the vehicle. Nowadays however, due to an increasing integration and modularization of components, elements, functions etc. in automotive vehicles, and in particular in the engines thereof, the conventional sensor devices cannot easily, conveniently and reliably be operationally connected. The invention intends to allow easy, convenient and reliable operation of the conventional diagnostic testing device with modern types of automotive vehicles . To achieve this goal, the system according to the invention is characterized in that the sensing means comprise a communication unit, operationally connectable to a diagnostic data communication port of the vehicle for communicating diagnostic data with the automotive vehicle via a diagnostic data communication link and a sensing signal generation unit for receiving at least a part of the diagnostic data from the communication unit and for deriving from at least the part of the diagnostic data a signal compatible with the sensing input of the diagnostic testing device. The communication interfacing unit thus receives diagnostic information from the vehicle via a diagnostic data communication port, which is currently available in (a majority of) all modern vehicles. The diagnostic data, or at least a part thereof which relates to the quantity which would according to the state of the art have been sensed by the respective sensing device, is transferred to the sensing signal generation unit which generates (e.g. making use of suitable hardware) a signal which is compatible with the sensing signal of the sensing device, as would have been generated according to the state of the art by the sensing means. Thus, it is now possible to use an existing diagnostic testing device with a modern vehicle equipped with a diagnostic data communication port, by instead of generating the sensing signal by sensing means dedicated for the specific diagnostic testing device, deriving data relating to the respective quantity to be sensed from the diagnostic data which is available from the diagnostic data communication port of the vehicle, and generating a signal from this data, the signal being compatible with the sensing signal. By providing this compatible signal to the diagnostic testing device, the testing can be performed with a wide variety of modern vehicles avoiding difficulties in establishing an operative connection between the respective sensing device and the vehicle. The diagnostic testing device can comprise a vehicle exhaust emissions tester. Such exhaust emissions tester, as stated above, is usually equipped with various sensing devices, such as a gas analyzing probe, an engine temperature probe, and a pick-up probe for picking up an ignition signal from an ignition cable of the engine of the vehicle. From this ignition signal, the testing device is able to derive a quantity representing an angular speed, such as a number of revolutions per minute ("RPM") , of the engine, as will be known per se to a person skilled in the art. According to the invention, in case that the diagnostic testing device is adapted to be provided with a plurality of sensing signals from e.g. a plurality of sensing devices, one or more of the plurality of sensing devices can be replaced by the combination of the communication interfacing unit and the sensing signal generation unit according to the invention. It is possible that for each of the sensing signals to be generated, a separate communication interfacing unit and a separate sensing signal generation unit is provided, however it is also possible that a single communication interfacing unit and a plurality of sensing signal generation units (e.g. one for each sensing signal to be generated) are provided, or it is possible that a plurality of communication interfacing units is provided, e.g. one for each sensing signal, combined with either a single sensing signal generation unit or a plurality thereof. The sensing signal provided by the sensing means advantageously comprises one or more of a group comprising a revolutions-per-time-unit (such as RPM) signal, an oil pressure signal, an oil and/or coolant temperature signal and a lambda sensor (s) signal (s). Of course, any other sensing signal which might be applied for diagnostic purposes, and which senses a quantity of (a part of) the vehicle, might be used. The communication unit advantageously comprises a serial diagnostic testing and readout device, the diagnostic data communication link comprising a serial diagnostic data communication link. Thus, a standard, commercially available tool, i.e. a serial diagnostic testing and readout device, which is commonly used in automotive servicing and diagnostics, can be applied, which reduces costs of the solution according to the invention, as the serial diagnostic testing and readout device is normally already available at a service station. It is possible that the communication unit, e.g. comprising the serial diagnostic testing and readout device, is adapted to select from the diagnostic data a part which relates, comprises information relating to, the quantity relating to the respective at least one sensing signal. Thus, preferably only a part of the diagnostic information relating to the quantity is forwarded to the sensing signal generation unit, which enables a more simple and straightforward design of the signal generation unit, as will be appreciated by the person skilled in the art. However it is also possible that the diagnostic data communication device forwards all information from the diagnostic data communication port, or any other suitable part thereof, to the sensing signal generation unit. Advantageously, the sensing signal is an analogue signal, such as a voltage value or a current value, however it is also possible that the information in the analogue signal is comprised in any other suitable parameter of the signal, such as a time between successive pulses, a frequency, a ripple, etc. Similar objectives, advantageous and goals are achieved with the method according to the invention, which is characterized by the step of generating the sensing signal comprises communicating diagnostic data with the automotive vehicle via a diagnostic data communication link and deriving from at least a part of the diagnostic data a signal compatible with the sensing input of the diagnostic testing device. The same or similar embodiments as applicable to the system according to the diagnostic system according to the invention are also applicable to the method according to the invention. The invention will now be described in more detail referring to the appended drawing, in which a non-limiting embodiment of the invention is shown, in which: fig. 1 shows a system for diagnosing an automotive vehicle according to the state of the art; fig. 2 shows a system for diagnosing an automotive vehicle according to the invention; and fig. 3 shows a block schematic view of a part of the system according to fig. 2. Fig. 1 shows an automotive vehicle 1 which is connected to a system 2 for diagnosing an automotive vehicle, in this example an exhaust emissions tester. The system 2 comprises a sensing means which in this example comprises an exhaust emissions probe 3, an oil temperature probe 4 and an ignition cable probe 5. The exhaust emissions probe 3 is operationally connectable, as schematically indicated, to an exhaust of the vehicle 1, while the oil temperature probe 4 is e.g. connectable to an existing oil temperature sensor in the engine, an oil outlet plug, oil inlet plug, oil level probe, or any other suitable location. The ignition cable probe 5 can be attached, e.g. clamped, to an ignition cable or any other suitable element of an ignition system of the vehicle 1. Each of the probes 3, 4, 5 provides a respective sensing signal which is provided, via a respective sensing input 3a, 4a, 5a to a diagnostic testing device 6. Each of the sensing inputs 3a, 4a, 5a of the testing device 6 is adapted to receive a respective sensing signal in a particular format, such as a voltage, a current of other suitable quantity and derives information from a particular parameter thereof, such as an amplitude, a frequency, a pulse width, a pulse repetition frequency, a pulse height, an amplitude or a frequency of a ripple, an (amplitude of) a specific frequency component, etc., depending on a type and characteristics of the specific sensing device for the specific sensing input. In this example, sensing inputs 3a and 4a might be adapted for receiving a voltage, an analogue value of the voltage representing a value of the quantity to be sensed, while the sensing input 5a receives a pulse shaped voltage signal representing a voltage value on the ignition cable to which the ignition cable probe 5 is clamped. The diagnostic testing device 6 is adapted to derive information from the sensing input 5a e.g. from a repetition frequency of the pulses. Further, it is possible that the exhaust emissions probe 3 comprises or is connected to multiple sensing devices for e.g. sensing various different gases, to which end the sensing input 3a might be adapted for receiving, either parallel (via respective conductors) or serially signals representing quantities sensed by the various sensing devices in the exhaust emissions probe 3. Fig. 2 again shows the vehicle 1, the exhaust emissions probe 3 which is operationally connected to the vehicle 1 and the diagnostic testing device 6. The exhaust emissions probe 3 is operationally connected to the diagnostic testing device 6 via the sensing input 3a. Instead of the oil temperature probe 4 and the ignition cable probe 5 however, a communication unit 7 (in this example a serial diagnostic testing and readout device) and a sensing signal generation unit 8 are applied. The serial diagnostic testing and readout device 7, which can e.g. comprise a commercially available readout tool, is connected via a serial diagnostic data communication link 8 to a diagnostic data communication port 9 of the vehicle 1. Via the serial diagnostic data communication link 8, diagnostic data is communicated between the vehicle 1 and the serial diagnostic testing and readout device 7. The serial diagnostic testing and readout device 7 is further operationally connected to the sensing signal generation unit 10. The sensing signal generation unit 10 receives, via any suitable communication link, such as a serial diagnostic data communication link, data from the serial diagnostic testing and readout device 7, the data comprising information concerning in this example oil temperature and rotational speed (RPM) of the engine. It is either possible that the serial diagnostic testing and readout device 7 communicates all data as received via the serial diagnostic data communication link 8 to the sensing signal generation unit 10, however preferably a suitable part of this data, such as only the data relating to oil temperature and revolutions, or any other subset comprising such data, is communicated to the sensing signal generation unit 10. Therefore, the serial diagnostic testing and readout device 7 can be supplied with specific software, as will be appreciated by the person skilled in the art, which is able to select data to be communicated to the sensing signal generation unit 10 from the data received via the serial diagnostic data communication link 8. The sensing signal generation unit 10 generates, making use of the data received from the serial diagnostic testing and readout device 7, a signal compatible with the sensing input 4a and a signal compatible with the sensing input 5a. Based on the data concerning revolutions of the engine, a pulse train is generated, as schematically indicated in fig. 2, the pulse train having electrical characteristics similar to the signal generated by the ignition cable probe 5 according to fig. 1. Similarly, an oil temperature signal is generated by the sensing signal generation unit 10, the oil temperature signal having similar electrical characteristics as the oil temperature signal generated by the oil temperature probe in the system according to fig. 1. Thus, the diagnostic testing device, being supplied via sensing input 4a with the oil temperature signal generated by the sensing signal generation unit 10, and supplied via the sensing input 5a with the ignition signal generated by the sensing signal generation unit 10, is, based on the signals provided on the sensing inputs 3a, 4a, 5a able to perform a diagnosis in a manner (at least largely) identical to the diagnostic testing device 6 according to fig. 1. In a practical implementation, no adaptations or modifications are foreseen for the diagnostic testing device 6 as compared to the testing device 6 according to fig. 1. The operation of the sensing signal generation unit 10 is described with reference to fig. 3, in which a block schematic view of the sensing signal generation unit 10 has been depicted. Data from the serial diagnostic testing and readout device is provided to the sensing signal generation unit 10 via the data connection 10a as depicted in fig. 2 and fig. 3, while the respective signals generated by the sensing signal generation unit are provided via the outputs 10b and 10c respectively to inputs 4a and 5a of the diagnostic testing device 6 in fig. 2. As depicted in fig. 3, the sensing signal generation unit comprises a processing unit 20 which receives the data from the input 10a and derives data concerning the respective sensing signal (s), in this example data concerning oil temperature and data concerning an engine speed (number of revolutions per time unit) from the data provided from the serial diagnostic testing and readout device 7. The detailed manner in which such operation is to be performed will, as will be appreciated by the person skilled in the art, depend on the form in which the data is provided to the sensing signal generation unit 10. In this example, data related to the oil temperature is provided to a digital-to-analogue converter 21 which generates an analogue signal at output 10b. Thus, the part of the diagnostic data relating to the quantity to be sensed is converted into a signal compatible with the respective sensing input of the diagnostic testing device 6. In this example, the oil temperature signal is an analogue signal, an amplitude, e.g. a voltage, providing information on the oil temperature. Therefore, the sensing signal generation unit 10 comprises a suitable means for generating an analogue voltage from the data provided, such as the digital-to-analogue converter 21. The ignition signal generated in fig. 1 by the ignition cable probe 5 however has a form of a pulse train originating from ignition pulses generated by an ignition system of the vehicle 1. Therefore, data concerning a number of revolutions per time unit of the engine is provided by the processing unit 20 to a pulse shaper circuit 22 which converts this data into a pulse train compatible with the input 5a of the diagnostic testing device 6 and having characteristics similar or identical to the signal as supplied by the ignition cable probe 5 in fig. 1. It will be appreciated by a person skilled in the art that instead of the digital-to-analogue converter 21 or the pulse shaper 22, different types of conversion circuits and software algorithms might be applied, depending on the characteristics of the signal to be supplied to the respective input of the diagnostic testing device 6. The conversion circuits can e.g. comprise a digital-to-analogue converter, a pulse generator, an oscillator having an adjustable frequency and/or amplitude, an amplifier, etc.. The conversion circuit (s) can be implemented in the form of analogue and/or digital electronic circuits, however it is also possible that the conversion circuit (s) is/are implemented by means of suitable software running on a processing unit, such as a digital signal processor (DSP) . With the system according to fig. 2 and fig. 3, the diagnostic testing device, such as the exhaust emissions tester 6, can be operated with any type of vehicle supplied with a diagnostic communication port while avoiding troublesome and labor intensive establishing of operational connection between various probes, such as the ignition cable probe, oil temperature probe, etc. and various parts of the vehicle 1. Alternatively to the system described in fig. 2, it is possible to omit the serial diagnostic testing and readout device 7, the serial diagnostic data communication link 8 being directly connected to the sensing signal generation unit 10. In this case, the processing unit 20 fulfills the function of the communication unit. The sensing signal generation unit can be a separate unit, however also it is also possible to integrate the sensing signal generation unit into the diagnostic testing device 6. Further, it is possible that the serial diagnostic testing and readout device is adapted by means of suitable software to send configuration instructions to the sensing signal generation unit, e.g. to make it suitable for a number of different exhaust emissions testers. The processing unit 20 can e.g. be adapted to change an amplification parameter, or one or more range parameters or any other parameter in the sensing signal generation unit to match an output of the sensing signal generation unit with an input of the particular exhaust emissions tester.

Claims

1. A system for diagnosing an automotive vehicle, the system comprising: sensing means for generating a sensing signal representative of a physical quantity of the automotive vehicle; and - a diagnostic testing device comprising a sensing input for receiving the sensing signal from a dedicated sensor device for cooperation with the testing device, characterized in that the sensing means comprise: a communication unit, operationally connectable to a diagnostic data communication port of the vehicle for communicating diagnostic data with the automotive vehicle via a diagnostic data communication link; and a sensing signal generation unit for receiving at least a part of the diagnostic data from the communication unit and for deriving from a least the part of the diagnostic data a signal compatible with the sensing input of the diagnostic testing device .

2. The system according to claim 1, wherein the diagnostic testing device comprises a vehicle exhaust emissions tester.

3. The system according to claim 1 or 2, wherein the sensing signal provided by the sensing means comprises one or more of a group comprising a revolutions-per-time-unit signal, an oil pressure signal, an oil temperature signal, an emission signal and a lambda sensor signal.

4. The system according to any of the preceding claims, wherein the communication unit comprises a serial diagnostic data communication device, the diagnostic data communication link comprising a serial diagnostic data communication link.

5. The system according to any of the preceding claims, wherein the communication unit is adapted to select from the diagnostic data a part which relates to the quantity and to forward the part to the sensing signal generation unit.

6. The system according to any of the preceding claims, wherein the sensing signal is an analogue signal.

7. A method for diagnosing an automotive vehicle, the method comprising: generating a sensing signal representative of a physical quantity of the automotive vehicle; and receiving the sensing signal by a diagnostic testing device comprising a sensing input for receiving the sensing signal from a dedicated sensor device for cooperation with the testing device, characterized in that the step of generating the sensing signal comprises : communicating diagnostic data with the automotive vehicle via a diagnostic data communication link; and deriving from at least a part of the diagnostic data a signal compatible with the sensing input of the diagnostic testing device.