SYSTEM FOR CHECKING A CORRECT MOUNTING OF A SENSOR

Abstract

The present disclosure shows a system for checking a correct mounting of a plurality of sensors, in particular of sensors mounted in an engine system, comprising a controller configured for receiving signals from the plurality of sensors. The controller is configured to monitor a sequence and/or timing of the signals received from the sensors and to evaluate it with respect to a sequence and/or timing of a switching of a power supply to the sensors for checking the correct mounting of the sensors.

Claims

1. A system for checking a correct mounting of a plurality of sensors, comprising a controller configured for receiving signals from the plurality of sensors, wherein the controller is configured to monitor a sequence and/or timing of the signals received from the sensors and to evaluate it with respect to a sequence and/or timing of a switching of a power supply to the sensors for checking the correct mounting of the sensors.

2. The system of claim 1, wherein the plurality of sensors are connected to a bus system and the signals from the sensors comprise communication signals exchanged via the bus system.

3. The system of any of claim 1, wherein the controller is configured to check the correct mounting of sensors by checking whether a sequence and/or point in time at which signals from a sensor are received or no longer received corresponds to an expected sequence and/or point in time with respect to a sequence and/or point in time of switching on or off of the power supply to the sensors.

4. The system of claim 1, wherein the controller is configured to control the switching on or off of the power supply to the plurality of sensors.

5. The system of claim 4, wherein the controller is configured to control the switching on or off of the power supply to the plurality of sensors to occur in a predetermined sequence and/or at different points in time.

6. The system of claim 5, wherein the controller is configured to delay or advance a switching on of the power supply to a first sensor with respect to a second sensor at start-up and/or to delay or advance a switching off of the power supply to the first sensor with respect to the second sensor at shut-down.

7. The system of claim 4, wherein the controller comprises a plurality of hardware switches configured to control the timing of the switching of the power supply to the plurality of sensors.

8. The system of claim 4, wherein the controller is configured to temporally switch the power supply to a first sensor on while the power supply to a second sensor and to all other sensors remains switched off and/or to temporally switch the power supply to the first sensor off while the power supply to the second sensor and to all other sensors remains switched on.

9. The system of claim 4, wherein the controller comprises a microcontroller for controlling the timing of the switching of the power supply to the plurality of sensors.

10. The system of claim 1, wherein the plurality of sensors are of the same type and only differ in their identifier.

11. The system of claim 1, wherein the plurality of sensors are NOx-sensors and/or NH3-sensors and/or temperature sensors.

12. The system of claim 1, wherein the plurality of sensors are sensors arranged on an exhaust gas aftertreatment system of an engine and/or are sensors arranged on different engine parts, in particular on different cylinders of the engine.

13. An engine comprising the plurality of sensors and the system according to claim 1.

14. A method for checking a correct mounting of a plurality of sensors according to claim 1, the method comprising: receiving signals from the plurality of sensors, monitoring a sequence and/or timing of the signals received from the sensors and checking the correct mounting of the sensors by evaluating the sequence and/or timing of the signals received from the sensors with respect to a sequence and/or timing of a switching of a power supply to the sensors.

15. The method of claim 14, further comprising: checking the correct mounting the sensors by checking whether a sequence and/or point in time at which signals from the sensors are received or no longer received corresponds to a sequence and/or expected point in time with respect to a switching on or off of the power supply to sensors; and/or controlling the switching on or off of the power supply to the sensors to occur in a predetermined sequence and/or at different points in time.

16. The system of claim 1, wherein the sensors are mounted in an engine system.

17. The system of claim 2, wherein the bus system is a CAN-bus system.

18. The system of claim 6, wherein the sensors are switched on one after the other on start-up or switched off one after the other on shut-down.

19. The system of claim 7, wherein the switches have different time-delays for switching on or off following a switching on or off signal, wherein the switches are on- or off-delay relays normally open with timed closed or opened contact.

20. The system of claim 14, wherein the sensors are mounted in an engine system.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0071] The drawings show:

[0072] FIG. 1: A timeline for three sensors in a first embodiment where there is a sequential timing of switch-on at startup;

[0073] FIG. 2: A timeline for three sensors in a second embodiment where there is a sequential timing of switch-off is at stop;

[0074] FIG. 3: A timeline for three sensors in a third embodiment where the power supply is sequentially switched-off for a predetermined time;

[0075] FIG. 4: A timeline for three sensors in a fourth embodiment where the power supply is sequentially switched-on for a predetermined time;

[0076] FIG. 5: an example of possible wiring for 3 sensors for startup sequencing; and

[0077] FIG. 6: an example of possible wiring for 3 sensors for any sequencing and

[0078] FIG. 7: an embodiment of a system of the present disclosure in a schematic drawing.

DETAILED DESCRIPTION

[0079] A schematic drawing of a general embodiment of a system of the present disclosure is shown in FIG. 7.

[0080] The system comprises a controller 10 and a plurality of sensors 1-8. The sensors are in communication with the controller via communication lines 15, for example of a bus system, such as a CAN bus or other serial bus. The communication lines 15 are also referred to as network in the following.

[0081] The sensors may in particular be used in an engine 20, such as an internal combustion engine. The controller 10 may in particular be part of an engine control unit (ECU).

[0082] For example, some of the sensors such as sensors 5 to 8 may be exhaust gas sensors arranged on exhaust gas ducts 25 of the engine 20. In particular, the sensors may be arranged upstream, on or downstream of a catalyst 30 arranged in an exhaust gas duct. In an embodiment, the sensors may measure NOx and/or NH3 in the exhaust gas in order to control an exhaust gas aftertreatment system, for example for controlling urea injection.

[0083] The engine 20 may comprise several exhaust gas ducts 25 with separate exhaust gas aftertreatment systems such as catalysts 30 arranged in parallel. Therefore, there may be a larger number of sensors used for controlling the exhaust gas aftertreatment systems.

[0084] Alternatively or in addition, some of the sensors such as sensors 1 to 4 are temperature sensors arranged on cylinder heads of the engine.

[0085] The controller 10 of the present disclosure is configured to monitor a timing of the signals received from the sensors 1 to 8 and to evaluate it with respect to a timing of a switching of a power supply to the sensors for checking the correct mounting of the sensors.

[0086] FIGS. 1 to 4 show different switching sequences that may be used for checking the correct mounting of the sensors.

[0087] All examples are for 3 sensors in order to make the schematics or timetables easier to understand, but the present disclosure and the working principles shown in the examples work with an unlimited number of sensors.

[0088] In the embodiments of the present disclosure shown in FIGS. 1 to 4, the power supply of the sensor is either:

[0089] temporally shifted (at start or stop) so that the transmission of information by the sensor is also shifted temporally (FIG. 1 and FIG. 2),

[0090] and/or

[0091] temporarily removed in order to interrupt the transmission of information by the sensors (FIG. 3)

[0092] and/or

[0093] temporarily provided in order to start the transmission of information by the sensors (FIG. 4).

[0094] This time shift, temporary removal or provision of the sensor information transmission is detected by the controller 10, which will check whether the actual offset or timing of missing information or provided information corresponds to the expected behavior.

[0095] If not a bad mounting will be detected by the controller 10 that supervises the sensors. The controller may in this case output a warning or error message in order to indicate that the sensors are not correctly mounted.

[0096] The present disclosure works with unlimited number of sensors.

[0097] In the embodiment shown in FIG. 1, the timeline for three sensors at startup is shown with the following phases:

[0098] Phase 1: Sensor 1 available on network

[0099] Phase 2: Sensors 1 and 2 available on network

[0100] Phase 3: Sensors 1, 2 and 3 available on network

[0101] In the embodiment shown in FIG. 1, the procedure to checking sensors 1 to N is as follows:

[0102] The first sensor 1 is fed with power, it starts and begins to send out information. The detection system of the controller 10 ensures that the information received corresponds to that of sensor 1.

[0103] The second sensor 2 is fed with power, it starts and begins to send out information. The detection system of the controller 10 ensures that the information received corresponds to that of sensor 2.

[0104] Sensor N is fed with power, it starts and begins to send out information. The detection system of the controller makes sure that the information received corresponds to that of sensor N.

[0105] In the embodiment shown in FIG. 2, the timeline for three sensors at stop is shown with the following phases:

[0106] Phase 1: All sensors available on network

[0107] Phase 2: Sensors 2 and 3 available on network

[0108] Phase 3: Sensor 3 available on network

[0109] In the embodiment shown in FIG. 2, the procedure to checking sensors 1 to N is as follows:

[0110] Power to the first sensor 1 is cut off, it stops and stops sending information. The detection system of the controller ensures that the information corresponding to that of sensor 1 is no longer available.

[0111] Power to the second sensor 2 is cut off, it stops and stops sending information. The detection system of the controller ensures that the information corresponding to that of sensor 2 is no longer available.

[0112] Power supply to sensor N is cut off, it stops and stops sending information. The detection system of the controller ensures that the information corresponding to that of sensor N and is no longer available.

[0113] In the embodiment shown in FIG. 3, the drawing shows a timeline for three sensors with the following phases:

[0114] Phase 1: Sensors 2 and 3 available on network

[0115] Phase 2: Sensors 1 and 3 available on network

[0116] Phase 3: Sensors 1 and 2 available on network

[0117] The individual sensors are therefore switched off for a predetermined period one after the other, and the controller checks whether the expected sensor is no longer available on the network.

[0118] In the embodiment shown in FIG. 4, the drawing shows a timeline for three sensors with the following phases:

[0119] Phase 1: Sensor 1 available on network

[0120] Phase 2: Sensor 2 available on network

[0121] Phase 3: Sensor 3 available on network

[0122] The individual sensors are therefore switched on for a predetermined period one after the other, and the controller checks whether the expected sensor is available on the network.

[0123] The correct sequence, timing and configuration of the phases may be stored in the controller in order to determine whether the actual sequence, timing and configuration corresponds to the correct one.

[0124] The controller may in particular check the correct sequence, timing and configuration of the phases relative to each other, i.e. without reference to a particular starting point.

[0125] For example, the controller may determine the expected points in time for receiving or no longer receiving signals in any of the following phases from detecting the first phase.

[0126] Alternatively or in addition, the controller may control or determine the points in time at which the power supply is switched on or off, and determine the expected points in time for receiving or no longer receiving signals from the points in time at which the power supply is switched on or off.

[0127] There are different ways to configure the wiring of the controller to perform the above-described checks.

[0128] In the embodiment shown in FIG. 5, the sequential switching of the power supply to the sensors is provided by hard-wired control components.

[0129] In the embodiment, the hard-wired control components are configured to sequentially switch on power to the different sensors at power-on.

[0130] In particular, the power supply to each sensor i is controlled by a relay K.sub.Ai. The relays have a time delay for switching on the power supply, which is different for each relay. In particular, the relays are On-Delay relays normally open, with timed closed contact.

[0131] A similar hard-wiring could also be used for sequential power-off, but the sequential power on is preferred because it will allow a check of the correct mounting and functioning of the sensors each time the machine is started.

[0132] FIG. 5 shows a wiring diagram for an alternative embodiment, where the switching of the power supply to the sensors is controlled individually by a software program running on the controller. The controller may either directly control the power supply, or may control switches or relays that switch the power supply on and off.

[0133] The embodiment shown in FIG. 5 may implement any of the switching sequences shown above. In particular, the software program running on the controller may comprise instructions for switching on and off the power supply in any of the sequences shown above.

[0134] Further, a software program running on the controller may comprise instructions for checking that the sensors are available or not available on the network in the expected order and/or at the expected points in time.