Patent ID: 12202462

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG.1illustrates a voltage-source sensor2of the prior art coupled, for example, to an engine control computer4. The voltage-source sensor2is, for example, a sensor dedicated to detecting the positioning of a camshaft of an internal combustion engine through the movement of teeth of said target in front of said voltage-source sensor2. Such a voltage-source sensor2generally comprises three pins with a first sensor pin2_1coupled, for example, to a first computer pin4_1and suitable for supplying said voltage-source sensor2with electrical power; a second sensor pin2_2coupled to a second computer pin4_2dedicated to receiving a signal which is representative of the position of the camshaft; and finally a third sensor pin2_3coupled to a third computer pin4_3which is generally coupled to an electrical ground of the motor vehicle. The internal structure of the voltage-source sensor2is well known to those skilled in the art; it will not be presented in detail here.

The engine control computer4has a hardware interface6comprising, for example, a sensor power-supply module8and a signal processing module10.

The sensor power-supply module8is suitable for supplying electrical power to the voltage-source sensor2. For this purpose, it has a first sensor power-supply module pin8_1suitable for generating said electrical power supply for said voltage-source sensor2through the first computer pin4_1. For example, the electrical power supply has a value of 5 V. The internal structure of the sensor power-supply module8is well known to a person skilled in the art and numerous variants are available to them.

In one exemplary embodiment, the sensor power-supply module8comprises an electrical power supply which may be a power supply which is internal to the engine control computer4and a so-called “pull-up” resistor12. Said pull-up resistor12has the role of biasing the voltage-source sensor2. The pull-up resistor12has a first resistor pin12_1coupled firstly to the electric power supply and secondly to the first sensor power-supply module pin8_1. It further comprises a second resistor pin12_2coupled to a second electric-power-supply module pin8_2.

The signal processing module10is suitable for shaping and/or filtering a signal originating from the voltage-source sensor2. For this purpose, the signal processing module10comprises a first signal processing module pin10_1, a second signal processing module pin10_2and a third signal processing module pin10_3.

For example, the first signal processing module pin10_1is coupled to the second computer pin4_2and also to the third signal processing module pin10_3. The second signal processing module pin10_2is coupled to the third computer pin4_3and the third signal processing module pin10_3is coupled to the second electric-power-supply module pin8_2. A fourth signal processing module pin10_4is suitable for generating a filtered signal for at least one other function of the engine control computer4.

Furthermore, the internal structure of the signal processing module10may comprise a first capacitor14having a first first-capacitor pin14_1and a second first-capacitor pin14_2. The second first-capacitor pin14_2is coupled to electrical ground and the first first-capacitor pin14_1is coupled firstly to a first resistor pin16_1and secondly to the third signal processing module pin10_3. Furthermore, the third pin10_3is coupled to the first pin10_1. The signal processing module10further has a resistor16having a second resistor pin16_2. The second resistor pin16_2is coupled to the fourth signal processing module pin10_4. The values of the various elements, such as the resistors and the capacitor, are well known to a person skilled in the art and are consequently not given here.

FIG.2shows an example of a current-source sensor20of the prior art. This current-source sensor20operates and is coupled to the engine control computer4. The current-source sensor20delivers information in the form of a current variation requiring a different hardware interface6for the engine control computer4in order to be able to detect close current levels originating from the current-source sensor20.

For this purpose, a resistor30known by a person skilled in the art as a shunt resistor may be used, comprising a first resistor pin30_1and a second resistor pin30_2. The first resistor pin30_1is coupled to the electrical power supply of said engine control computer4, the second resistor pin30_2is coupled firstly to the second computer pin4_2and secondly to a first conversion device pin32_1. The conversion device32is suitable for comparing and matching the voltage applied to the second resistor pin30_2and the reference voltage applied to the second conversion device pin32_2.

The conversion device32is, in one exemplary embodiment, a comparator assembly produced using an operational amplifier. The conversion device32further has a second conversion device pin32_2coupled to a reference voltage. The value of the reference voltage may, for example, be 4.5 V. Furthermore, the conversion device32has a third conversion device pin32_3coupled to internal functions of the engine control computer4. The latter is therefore suitable for generating an electrical signal in the form of at least two voltage levels which are representative of the current flowing through the shunt resistor30. Preferably, the shunt resistor30has a relatively low value of the order, for example, of 10 ohms.

As mentioned above in the text of the description, for each type of sensor2,20, it is therefore necessary, upstream, to modify the internal structure of the hardware interface6.

An aspect of the invention proposes, as illustrated inFIG.3, a novel hardware interface6allowing either a voltage-source sensor or a current-source sensor to be coupled without modifying the internal structure of the hardware interface6upstream.

To do this, ingeniously, a hardware interface6is proposed comprising an adaptation module50and a processing module60. Thanks to this new hardware interface6, it is now possible to connect either a voltage-source sensor or a voltage-source sensor to the engine control computer4without modifying the internal interface of said engine control computer4.

The adaptation module50has, in one embodiment of the invention, a first adaptation module pin50_1, a second adaptation module pin50_2and a third adaptation module pin50_3, which are coupled to the first computer pin4_1, to the second computer pin4_2and to the third computer pin4_3, respectively. The adaptation module50also has at least one fourth adaptation module pin50_4.

The first sensor detection module pin50_1, the second sensor detection module pin50_2and the third sensor detection module pin50_3are adapted to receive signals from a sensor2,20coupled to said pins. As a variant, at least one of these three pins is suitable for supplying electrical energy to the sensor2,20.

As mentioned above in the text of the description, in the case of a voltage-source sensor2, the signal generated by said sensor2coupled to said pins of said engine control computer4is typically of the order of 5 V at rest, that is to say with the engine off.

In addition, as mentioned above in the text of the description, in the case of a current-source sensor20, the signal generated by said sensor20coupled to said pins of said engine control computer4is typically of the order of 4.5 V at rest, that is to say with the engine off.

Ingeniously, the adaptation module50is suitable for firstly detecting the type of sensor2,20coupled to the engine control computer4and secondly adapting the impedance for these input pins in order to allow both correct operation of the sensor2,20and also reading of the information delivered by the latter.

Thus, for example, in one embodiment of the invention, when the sensor2,20coupled to the engine control computer4is a voltage-source sensor, the adaptation module50selects between the pins of said computer4(which are coupled to the sensor2) a resistor with a high impedance of the order of 1000 ohms. The equivalent electronic circuit in this embodiment is then the circuit shown inFIG.1. The operation of the adaptation module50in this embodiment is also similar to that of the electronic circuit ofFIG.1presented earlier.

If the sensor20is a current-source sensor then the adaptation module50selects between the pins of said computer4(which are coupled to the sensor20) a resistor with a relatively low impedance of the order of 10 ohms. For example, the equivalent electronic circuit in this embodiment is the circuit shown inFIG.2; the operation is also identical to that inFIG.2.

FIG.4presents an exemplary embodiment of the adaptation module50and of the processing module60, which are brought together in a hardware interface100allowing either a voltage-source sensor2or a current-source sensor20to be coupled without modifying the internal structure of the hardware interface100upstream.

For this purpose, ingeniously, what is proposed is a hardware interface100which is suitable for connecting either a voltage-source sensor2or a current-source sensor20to the engine control computer4without any need to modify the hardware interface100of said engine control computer4. Thus, advantageously, the hardware interface100is compatible with the two types of sensors2,20.

The hardware interface100comprises, in one preferred embodiment, a first hardware interface input100_1, a second hardware interface input100_2and a third hardware interface input100_3, which are coupled to the first computer pin4_1, to the second computer pin4_2and to the third computer pin4_3, respectively. The hardware interface100further comprises a first hardware interface output100_4coupled to devices which are internal and/or external to the engine control computer4.

The hardware interface100comprises a first resistor110, a second resistor120, a transistor130, and a comparator140.

The first resistor110comprises a first first-resistor pin110_1and a second first-resistor pin110_2. The second resistor120comprises a first second-resistor pin120_1and a second second-resistor120pin120_2. The first first-resistor pin110_1is coupled firstly to the first hardware interface pin100_1and secondly to a first transistor pin130_1. The second first-resistor pin110_2is coupled firstly to the first second-resistor pin120_1and secondly to a second transistor pin130_2. Furthermore, the transistor130comprises a third transistor pin130_3corresponding, in the case of an MOS (metal oxide semiconductor) transistor130, to the gate, as is known by a person skilled in the art.

The second second-resistor pin120_2is coupled firstly to the second hardware interface pin100_2and secondly to a second comparator input140_2. The comparator140further comprises a first input140_1coupled to a reference voltage which may have, in one exemplary embodiment, a value of 4.5 V. The first comparator output140_3is coupled to the first hardware interface output100_4. The third hardware interface input100_3is coupled to a ground of the motor vehicle.

Advantageously, by virtue of the hardware interface100according to an aspect of the invention and, more precisely, by virtue of the combination of the coupling of the first resistor110, of the second resistor120and of the transistor130, it is possible to select a low impedance value corresponding to the value of the second resistor120or a high impedance value corresponding to the value of the first resistor110added to the value of the second resistor120between the first hardware interface pin100_1and the second hardware interface pin100_2. What is understood by low impedance value is a value of the order of ten ohms and by high impedance value a value of the order of a thousand ohms. Thus, advantageously, the selection of the impedance value allows either a voltage-source sensor2or a current-source sensor2to be connected to the terminals of the computer4without modifying the hardware interface100.

As mentioned above in the text of the description, either a voltage-source sensor2or a current-source sensor20may thus be coupled to the first computer pin4_1, to the second computer pin4_2and to the third computer pin4_3.

An aspect of the invention therefore proposes a method making it possible to automatically detect the type of sensor2,20and furthermore to configure the computer4according to the type of sensor2,20coupled.

To do this, as illustrated inFIG.5, a first step e1) is first carried out consisting of waiting for the computer4to be switched on, that is to say powered up.

Once the computer4has been powered up, a second step e2) is performed consisting of selecting an impedance between the first computer pin4_1and the second computer pin4_2corresponding/compatible to/with that of a voltage-source sensor2. To do this, the method of an aspect of the invention provides for the transistor130to be controlled in open circuit mode, that is to say that the first resistor110is no longer short-circuited by the transistor130in order to apply between the first computer pin4_1and the second computer pin4_2an impedance compatible with a voltage-source sensor2coupled to said pins.

According to the method of an aspect of the invention, during a third step e3, software configuration of the hardware interface100is performed in order to allow the signals delivered by the voltage-source sensor2to be read.

During a fourth step e4, the method performs an analysis of the signal from the sensor2coupled to the pins4_1and4_2. If the measured value is greater than a threshold value Vref then the method moves to a fifth step e5 and if the measured value is less than Vref the method provides for movement on to a sixth step e6. This comparison is for example carried out by the comparator140.

The fifth step e5, according to the method of an aspect of the invention, corresponds to the presence of the voltage-source sensor2coupled between the first computer pin4_1and the second computer pin4_2. Thus, the computer may for example restore parameters in memory corresponding to the parameters of a voltage-source sensor2in order to calibrate and measure the signals from said voltage-source sensor2once the internal combustion engine is in operation.

The sixth step e6, according to the method of an aspect of the invention, corresponds to the presence of a current-source sensor20coupled between the first computer pin4_1and the second computer pin4_2. Thus, the computer may for example restore parameters in memory corresponding to the parameters of a current-source sensor20in order to calibrate and measure the signals from said current-source sensor20once the internal combustion engine is in operation.

Advantageously, thanks to an aspect of the invention, the detection of the type of sensor2,20is carried out instantaneously before, for example, the internal combustion engine is started. Furthermore, thanks to an aspect of the invention, it is possible to change the sensor2,20and also to change the type of sensor without performing software calibration.

Thus, thanks to an aspect of the invention, it is now possible to couple either a voltage-source or current-source sensor to an engine control computer without prior calibration. In addition, ingeniously, no software calibration is necessary.

In one variant embodiment, a recording module (not shown in the figures) is also used in the hardware interface, making it possible, after detection of the type of sensor, to record the type of sensor connected to said engine control computer. Thus, the type of sensor coupled to said engine control computer is ingeniously reset each time the engine is started.

In another variant, the hardware interface includes a module for detecting teeth on the signal delivered by the sensor.