Magnetic sensors for vehicle drive shafts

Abstract

The invention relates to a sensor (25) for a motor vehicle (1), the vehicle (1) comprising a combustion engine (10) and an engine control computer (20), the engine (10) comprising at least one drive shaft (15) capable of being driven in rotation, the at least one drive shaft (15) having at least one magnetic element (150), the sensor (25) being arranged facing the at least one magnetic element (150), the computer (20) being configured to determine the angular position of the at least one drive shaft (15) relative to a predefined reference angular position based on an output signal provided by the sensor (25), the sensor (25) being characterized in that it is capable of generating a square wave output signal by associating each initial moment with a predefined angular position of the drive shaft (15), wherein each square wave is characterized by an initial moment and a time width.

Description

Technical Field

[0001] The present invention relates to the field of combustion engines for vehicles, especially motor vehicles, and more particularly to sensors and methods for synchronizing combustion engines. Background Art

[0002] As is well known, a combustion engine for a motor vehicle comprises a plurality of hollow cylinders, each of which defines a combustion chamber into which a fuel-air mixture is injected. This mixture is compressed and ignited within the cylinder by a piston, which in turn causes the piston to move translationally within the cylinder. The movement of the piston in each cylinder of the engine drives the rotation of the engine shaft (called the "crankshaft"), which in turn drives the wheels of the vehicle via a transmission system.

[0003] Air is injected into the combustion chamber via one or more intake valves, which open and close regularly. Similarly, gases generated from the fuel-air mixture are exhausted through one or more exhaust valves. These valves are connected to one or more camshafts, which continuously control the opening and closing of these valves. Notably, the crankshaft and camshaft are mechanically connected via a timing belt or chain.

[0004] In order to optimize the operation of a combustion engine, and in particular to determine the appropriate time to compress the fuel-air mixture in each cylinder, the combustion engine must be phased.

[0005] This is because during an engine cycle, the crankshaft rotates twice while the camshaft rotates only once. It is also necessary to know whether the crankshaft is in its first or second revolution in the engine cycle in order to inject fuel at the correct time and into the correct cylinder. This step is called engine synchronization.

[0006] To this end, a crankshaft sensor and a camshaft sensor are installed in the vehicle to measure the angular position of the crankshaft and the angular position of the camshaft, respectively.

[0007] To this end, in a first existing solution, each sensor is mounted facing a toothed target fixed to the shaft and measures the variations in the magnetic field generated by the teeth passing in front of the sensor. The sensor thus generates a sinusoidal signal that is sent to the vehicle's engine control computer, which analyzes it to determine the shaft's angular position. Knowing the angular positions of the crankshaft and the camshaft, the computer can determine which revolution of the crankshaft is in the engine cycle and thus synchronize the engine.

[0008] A second known solution is the use of a camshaft sensor, referred to as "magnetic" because it is associated with a magnet fixed to the camshaft. This sensor instantly determines the angular position value of the camshaft based on the movement of the magnet in the vicinity of the sensor, which causes the magnetic field to vary according to two sinusoidal components that are phase-shifted with respect to one another.

[0009] The magnetic sensor sends digital information on the angular position of the magnet in real time via a dedicated digital communication bus to the vehicle's engine control computer so that the computer can manage the injection of fuel into the cylinders.

[0010] Today, most vehicles with combustion engines use the first solution of sensors connected to toothed targets, but the use of the second sensor solution is becoming increasingly advantageous for car manufacturers. However, the use of a dedicated digital communication bus makes the vehicle more complex and requires modifying the intelligence of the engine control computer, which is particularly expensive.

[0011] Therefore, there is a need for a solution that can at least partially overcome these disadvantages. Summary of the Invention

[0012] The present invention relates to a sensor for a motor vehicle, the vehicle comprising a combustion engine and an engine control computer, the engine comprising at least one drive shaft capable of being driven in rotation, the at least one drive shaft having at least one magnetic element, the sensor being arranged facing the at least one magnetic element, the computer being configured to determine the angular position of the at least one drive shaft relative to a predefined reference angular position based on an output signal provided by the sensor, the sensor being notable in that it is capable of generating a square wave output signal based on a measurement result of the absolute angular position of the drive shaft in the signal, wherein each square wave is characterized by an initial moment and a time width by associating each initial moment with a predefined angular position of the drive shaft.

[0013] In this way, a sensor associated with a magnetic element can be operated with an engine control computer configured to operate with a sensor associated with a toothed target. In other words, in the present case, the absolute angular position measuring sensor thus modified according to the invention makes it possible to have a drive shaft that is not provided with any type of toothed target, without requiring modifications to the computer used in the vehicle.

[0014] Furthermore, the sensor makes it possible to avoid adding a digital communication bus dedicated to exchanging data between the sensor and the computer.

[0015] Therefore, the sensor according to the invention also makes it possible to reduce the manufacturing costs of combustion engines, since it avoids adding an additional communication bus, and it makes it possible to use drive shafts not provided with any type of toothed targets.

[0016] The camshaft sensor also makes it possible to simplify the structure of the engine.

[0017] The sensor is preferably configured to:

[0018] i. measuring the magnetic field generated by at least one magnetic element passing in front of the sensor as the drive shaft rotates,

[0019] ii. generating the cosine and sine components of the measured magnetic field,

[0020] iii. generating an intermediate signal based on the cosine component and the sine component, the intermediate signal giving the absolute angular position of the drive shaft,

[0021] iv. generating a square wave output signal of the sensor by associating each initial moment with an absolute angular position of the generated intermediate signal corresponding to a predefined angular position of the drive shaft over one complete revolution of the drive shaft.

[0022] Advantageously, each initial time instant represents a rising edge or a falling edge of the square wave.

[0023] Advantageously, the magnetic element is a magnet comprising two poles and fixed to one end of the drive shaft.

[0024] Preferably, the magnetic element takes the form of a metal disc which is fixed to a flat face of the end of the drive shaft.

[0025] The invention also relates to a vehicle, in particular a motor vehicle, comprising a combustion engine and an engine control computer, the engine comprising at least one drive shaft capable of being driven in rotation, the at least one drive shaft having at least one magnetic element, the vehicle being notable in that it comprises a sensor as described above for measuring the absolute angular position of the drive shaft, the computer being configured to determine the angular position of the at least one drive shaft relative to a predefined reference angular position based on a square-wave output signal provided by the sensor.

[0026] The invention also relates to a method for generating an output signal implemented by a sensor as described above, the method being notable in that it comprises a step of generating a square wave output signal based on the measurement results of the absolute angular position of the drive shaft, wherein each square wave is characterized by an initial moment and a time width by associating each initial moment with a predefined absolute angular position of the drive shaft.

[0027] The method preferably comprises the following steps:

[0028] i. measuring the magnetic field generated by at least one magnetic element passing in front of the sensor as the drive shaft rotates,

[0029] ii. generating the cosine and sine components of the measured magnetic field,

[0030] iii. generating an intermediate signal based on the cosine component and the sine component, the intermediate signal giving the absolute angular position of the drive shaft,

[0031] iv. generating a square wave output signal of the sensor by associating each initial moment with an absolute angular position of the generated intermediate signal corresponding to a predefined angular position of the drive shaft over one complete revolution of the drive shaft.

[0032] The invention also relates to a computer program product, notably comprising a set of program code instructions which, when executed by one or more processors, configure the one or more processors to implement the method described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Other features and advantages of the present invention will become more apparent from reading the following description, which is purely illustrative and should be read with reference to the accompanying drawings, in which:

[0034] [ Figure 1 ] Figure 1 An embodiment of an engine according to the present invention is schematically shown,

[0035] [ Figure 2 ] Figure 2 Shows the installation according to Figure 1 An embodiment of a magnetic element on a camshaft of an engine,

[0036] [ Figure 3 ] Figure 3 An embodiment of a camshaft sensor according to the present invention is shown.

[0037] [ Figure 4 ] Figure 4 An embodiment of the method according to the present invention is schematically shown,

[0038] [ Figure 5 ] Figure 5 An embodiment of the step of generating a cosine component and a sine component, and an embodiment of the step of generating an intermediate signal according to the method of the present invention are shown,

[0039] [ Figure 6 ] Figure 6 shows intermediate signals within one period of the cosine component and the sine component generated in the step of generating the intermediate signal according to the method of the present invention,

[0040] [ Figure 7 ] Figure 7 shows an embodiment of an output signal generated in the step of generating an output signal of the method according to the present invention,

[0041] [ Figure 8 ] Figure 8 Another embodiment of an output signal generated in the step of generating an output signal of the method according to the present invention is shown. DETAILED DESCRIPTION

[0042] The invention will be described with the object of being implemented in a motor vehicle. However, any embodiment in a different context, in particular for any vehicle comprising a combustion engine whose crankshaft and camshaft must be synchronized, is also the object of the invention.

[0043] Figure 1 An example of a vehicle 1 according to the invention is shown.

[0044] Vehicle 1

[0045] The vehicle 1 comprises a combustion engine 10 and a computer 20 , referred to as an “engine control computer”, capable of controlling said combustion engine 10 , in particular by commanding the injection of fuel into the cylinders 11 of said combustion engine 10 .

[0046] engine

[0047] The combustion engine 10 includes a plurality of cylinders 11 , a crankshaft 13 , at least one camshaft 15 , a crankshaft sensor 23 , and at least one camshaft sensor 25 .

[0048] In this non-limiting example, the combustion engine 10 includes a bank of cylinders 11 connected to a camshaft 15 and to a crankshaft 13. However, in another embodiment, the combustion engine 10 may include more than one bank of cylinders 11, each bank of cylinders 11 being associated with a different camshaft 15, and the multiple banks of cylinders 11 being connected to a single crankshaft 13.

[0049] 1) Cylinder 11

[0050] A bank of cylinders 11 includes a plurality of cylinders 11, such as two, three, four, five or six cylinders 11, each of which defines a combustion chamber 11A in which a piston 12 slides, the movement of the piston being driven by compression and expansion of gas caused by compression of a fuel-air mixture introduced into the combustion chamber 11A.

[0051] More specifically, in this example, combustion engine 10 is a four-stroke engine. Similarly, during operation of engine 10, each cylinder 11 undergoes four operating phases: an intake phase, in which air and fuel enter combustion chamber 11A of cylinder 11; a compression phase, in which the resulting mixture is compressed, with combustion occurring at the end of this compression phase; an expansion phase, in which the gases caused by the combustion of the mixture expand, generating thrust for piston 12; and an exhaust phase, in which the gases are exhausted from combustion chamber 11A. These four phases form a repetitive cycle for combustion engine 10. During the intake and expansion phases, piston 12 descends to a low position. During the compression and exhaust phases, piston 12 ascends to a high position.

[0052] 2) Camshaft 15

[0053] Air and gas are introduced into and exhausted from the combustion chamber 11A through an intake valve 14A and an exhaust valve 14B, respectively, which are connected to corresponding camshafts 15 of the exhaust cylinder 11 .

[0054] More specifically, the rotating camshaft 15 allows the intake valve 14A and exhaust valve 14B of each combustion chamber 11A to be alternately opened and closed. Alternatively, the engine 10 of the vehicle 1 may include two camshafts 15 per bank of cylinders 11, one dedicated to the intake valve 14A and the other dedicated to the exhaust valve 14B. Similarly, in this example, each cylinder 11 is connected to an intake valve 14A and an exhaust valve 14B; however, each cylinder 11 may also be connected to multiple intake valves 14A and multiple exhaust valves 14B.

[0055] 3) Crankshaft 13

[0056] Each cylinder 11 is connected to a crankshaft 13 via its piston 12. The crankshaft 13 is thus set in rotation by the thrust of each piston 12, and this rotation makes it possible to transfer energy via a flywheel (not shown), thereby driving the wheels of the vehicle 1 in rotation.

[0057] During the engine cycle, the crankshaft 13 rotates twice while the camshaft 15 rotates only once. In other words, the rotation speed of the crankshaft 13 is twice that of the camshaft 15.

[0058] Therefore, in order to ensure correct operation of the combustion engine 10, it is necessary to synchronize the combustion engine 10 and therefore synchronize the angular positions of the camshaft 15 and the crankshaft 13. In other words, the angular positions of the camshaft 15 and the crankshaft 13 need to be known first.

[0059] To determine the angular position of crankshaft 13, crankshaft 13 includes a toothed wheel 130, commonly referred to by those skilled in the art as a "crankshaft target." For example, toothed wheel 130 may have a predetermined number of evenly spaced teeth and a free space that serves as an angular position reference. In another embodiment, toothed wheel 130 may include more than one free space. Because such toothed wheels 130 are known per se, they will not be described further herein.

[0060] Crankshaft sensor 23

[0061] The crankshaft sensor 23 is installed to face the gear wheel 130 so as to detect the empty space of the gear wheel 130 and the passing of the teeth of the gear wheel 130 in front of the crankshaft sensor 23 when the crankshaft 13 rotates.

[0062] To this end, the crankshaft sensor 23 is configured to transmit a signal comprising rising and falling edges, which represent the passage of teeth of the toothed wheel 130 and the free space of the toothed wheel 130 .

[0063] For example, the crankshaft sensor 23 may be a Hall Effect sensor known to those skilled in the art.

[0064] Camshaft 15

[0065] In this example, reference Figure 2 , each camshaft 15 takes the form of a cylindrical shaft having a circular cross-section.

[0066] In order to determine the angular position of the camshaft 15 , the camshaft 15 has at least one magnetic element 150 . In the present case, in order to simplify the description, it will be considered that the camshaft 15 comprises only a single magnetic element 150 .

[0067] The magnetic element 150 is preferably a magnet comprising two poles.

[0068] For example, the magnetic element 150 may be fixed to one end of the camshaft 15 .

[0069] In this example, if Figure 2 As shown, the magnetic element 150 takes the form of a metal disc fixed to a flat face at the end of the camshaft 15 , coaxially with said shaft, that is to say so that the axis of rotation of the disc coincides with the axis of rotation of the camshaft 15 .

[0070] According to another embodiment, the magnetic element 150 is in the form of a metal ring, more particularly a volume formed by a circle or a ring, which rotates about an axis of rotation lying in the plane of the circle or the ring and not passing through the center of the circle or the ring. The metal ring is fixed to a flat surface at the end of the camshaft 15, coaxially with the shaft, that is, so that the axis of rotation of the metal ring coincides with the axis of rotation of the camshaft 15.

[0071] Camshaft sensor 25

[0072] Reference again Figure 1 The combustion engine 10 comprises a camshaft sensor 25, which is called a "magnetic" camshaft sensor and is mounted facing the magnetic element 150. The camshaft sensor 25 comprises three connectors: a connector dedicated to supplying power to the camshaft sensor 25; a connector dedicated to grounding; and a connector dedicated to communication (in particular with a computer). In other words, with reference to Figure 3 The camshaft sensor 25 includes a connecting pin 251 , and the connecting pin 251 includes three connectors 252 .

[0073] As the camshaft 15 is driven in rotation, the camshaft sensor 25 is configured to generate a signal that enables the computer 20 to determine the angular position of the camshaft 15 .

[0074] To this end, the camshaft sensor 25 is configured to measure the magnetic field generated by at least one magnetic element 150 as the camshaft 15 rotates (this magnetic field as a function of time) in order to determine the absolute angular position of the camshaft 15. Such a sensor is understood to be a sensor that is capable of determining the angular position of the camshaft with an accuracy of 0.1°. However, the implementation of such an absolute angle measurement sensor requires modifications to the communication bus between the sensor and the computer 20, and also to the computer 20 in order to be able to process the data. This is because the amount of these measurement results and therefore the data generated by the sensor is constantly increasing and is continuously transmitted, and it is therefore necessary to appropriately determine the dimensions of the communication bus and the processing and data reception capabilities of the computer 20. However, these modifications are expensive. Therefore, the present invention proposes a sensor that avoids having to make such modifications.

[0075] More specifically, the camshaft sensor 25 is configured to measure the magnetic field in a plane that includes the end of the camshaft 15 to which the magnetic element 150 is fixed.

[0076] In addition, reference Figure 5 In the first graph of FIG, the camshaft sensor 25 is configured to generate a cosine component Bx and a sine component By of a pre-measured magnetic field as a function of time T.

[0077] In other words, the cosine component Bx is expressed as Figure 2 The cosine of the absolute angular position a1 is shown.

[0078] In addition, the sinusoidal component By is expressed as Figure 2 The sine of the absolute angular position a1 is shown.

[0079] The camshaft sensor 25 is further configured to generate an intermediate signal based on the generated cosine component Bx and the generated sine component By. To this end, the camshaft sensor 25 is configured to determine the absolute angular position a1 of the camshaft 15 at all times (in other words, for each set of values ​​including the cosine component Bx and the sine component By).

[0080] It is worth noting that the camshaft sensor 25 is configured to determine the absolute angular position a1 of the camshaft 15 at all times by determining the angular position a1 that satisfies the following formula:

[0081] By 2 +Bx 2 =1where Bx=cos(a1), By=sin(a1).

[0082] Furthermore, the period of the cosine component Bx and the sine component By represents a cycle of the combustion engine 10 and, therefore, a rotation of the camshaft 15. In other words, for a cycle of the combustion engine 10, the set of determined angular positions a1 of the camshaft 15 varies from 0° to 360°, denoted as °CAM.

[0083] According to the present invention, the camshaft sensor 25 is also capable of generating a square wave output signal for each cycle of the combustion engine 10 (and therefore for each rotation of the camshaft 15), wherein each square wave is characterized by an initial moment and a time width by associating each initial moment with a predefined absolute angular position of the camshaft 15. More specifically, each initial moment is associated with an absolute angular position a1 of the generated intermediate signal, which corresponds to the predefined angular position of the camshaft 15.

[0084] Therefore, the output signal is generated during at least one complete revolution of the camshaft 15 .

[0085] The set of predefined angular positions is noted as a set of predefined angular positions between 0° CAM and 360° CAM, the interval between 0° CAM and 360° CAM representing one complete revolution of the camshaft 15. More specifically, the set of predefined angular positions includes: n angular position values, where n is a natural number distributed in a regular interval, in particular between 1 and 360, more particularly between 6 and 120; and at least one angular position value, referred to as a "reference" or "asymmetric" angular position value, so that the angular position of the camshaft 15 at a given moment can be determined.

[0086] In the example presented here, the number of uniformly distributed values ​​n of predefined angular positions is equal to 12. Thus, the set of predefined angular positions includes: the value 0° CAM; and all multiples of 30° CAM up to 360° CAM; and a dedicated reference angular position value predefined, for example, at 105° CAM.

[0087] In other words, the camshaft sensor 25 is configured to select a determined angular position corresponding to (or, in other words, equal to) a predefined angular position for each cycle of the combustion engine 10. Furthermore, as described above, the camshaft sensor 25 is configured to associate each determined and selected angular position with the initial instant of the square wave.

[0088] The camshaft sensor 25 is also configured to associate a rising edge or a falling edge of the square wave with each initial time.

[0089] Furthermore, the camshaft sensor 25 is configured to define the time width and voltage amplitude of each square wave. Note that the time width of each square wave is defined based on a predefined time width. The voltage amplitude corresponds specifically to the voltage supplied to the camshaft sensor 25.

[0090] For example, the predefined time width is equal to a value between 20 μs and 150 μs, preferably 45 μs.

[0091] The voltage amplitude varies in particular between 0 and 5 volts.

[0092] The camshaft sensor 25 is also configured to transmit the generated output signal to the engine control computer 20 .

[0093] Computer 20

[0094] In order to synchronize the angular position of the crankshaft 13 and the angular position of the camshaft 15 , an engine control computer 20 is installed in the vehicle and is connected to a crankshaft sensor 23 and to a camshaft sensor 25 .

[0095] The computer 20 is configured to receive the signal transmitted by the crankshaft sensor 23 and to determine, based on the transmitted signal, an angular position of the crankshaft 13 between 0° and 720°, denoted as °CRK.

[0096] The computer 20 is also configured to receive the output signal generated and transmitted by the camshaft sensor 25. Furthermore, the computer 20 is configured to detect a square wave in the output signal, referred to as a "reference" square wave, that corresponds to a predefined reference angular position (in other words, a reference tooth or reference recess). Finally, the computer 20 is configured to determine the angular position of the camshaft between 0° CAM and 360° CAM based on the transmitted output signal and relative to the detected reference square wave.

[0097] The computer may also be configured to determine the rotational speed of the camshaft 15 .

[0098] method

[0099] refer to Figure 4An embodiment of a method implemented by the combustion engine 10 described above will now be described. According to this embodiment of the method, the rotational speed of the camshaft 15 is constant. However, it goes without saying that the rotational speed may vary from one rotation of the camshaft 15 to the next.

[0100] Measuring E1 magnetic field

[0101] Firstly, the method comprises a step E1 of measuring the magnetic field generated by at least one magnetic element 150 as a function of time T while the camshaft 15 rotates.

[0102] Specifically, when the camshaft 15 rotates, the magnetic element 150 also rotates about its rotation axis, thereby causing the magnetic field generated by the magnetic element 150 to change.

[0103] More specifically, during this step, the camshaft sensor 25 measures the magnetic field within the plane in which the magnetic element 150 is defined.

[0104] Generate E2 cos / sin components

[0105] The method further comprises a step E2 of generating, by means of the camshaft sensor 25 , a cosine component Bx and a sine component By of a pre-measured magnetic field as a function of time T.

[0106] refer to Figure 5 , the cosine component Bx and the sine component By of the measured field are shown in the first diagram.

[0107] In other words, the cosine component Bx is expressed as Figure 2 The cosine of the absolute angular position a1 is shown.

[0108] In addition, the sinusoidal component By is expressed as Figure 2 The sine of the absolute angular position a1 is shown.

[0109] Generate E3 intermediate signal

[0110] According to the invention, the method comprises a step E3 of generating an intermediate signal by means of the camshaft sensor 25 based on said cosine component Bx and said sine component By.

[0111] refer to Figure 5 More specifically, during this step, the camshaft sensor 25 determines the absolute angular position a1 of the camshaft 15 at all times (in other words, for each set of values ​​of the cosine component Bx and the sine component By).

[0112] The intermediate signal is therefore defined by the variation in the absolute angular position a1 of the camshaft 15 as a function of time T.

[0113] Furthermore, since the rotational speed of the camshaft 15 is constant, the intermediate signal is a linear function.

[0114] For example, in order to determine the absolute angular position a1 of the intermediate signal for each time instant, the camshaft sensor 25 determines the angular position a1 that satisfies the following formula:

[0115] By 2 +Bx 2 =1where Bx=cos(a1), By=sin(a1).

[0116] Generate E4 output signal

[0117] The method comprises a step E4 of generating, by means of the camshaft sensor 25 , a square-wave output signal for each cycle of the combustion engine 10 .

[0118] Therefore, reference Figure 6 , the intermediate signal is therefore considered over the period of the cosine component Bx and the sine component By.

[0119] It is noteworthy that each square wave of the output signal is characterized by an initial moment and a time width. Each initial moment is associated with a predefined angular position of the camshaft 15. More specifically, each initial moment is associated with an absolute angular position a1 of the generated intermediate signal, which corresponds to the predefined angular position of the camshaft 15.

[0120] Thus, the initial moment of each square wave is defined based on the generated intermediate signal and a set of predefined angular positions between 0° CAM and 360° CAM.

[0121] More specifically, on the intermediate signal, a determined absolute angular position a1 is selected which corresponds to a predefined angular position.

[0122] Each initial moment is then associated with a selected, determined angular position.

[0123] Each initial moment is associated with a square wave, and more specifically with a rising edge or a falling edge of the square wave.

[0124] Furthermore, in order to generate the output signal, as mentioned above, the time width of each square wave has been predefined, in particular between 20 μs and 150 μs, preferably 45 μs.

[0125] Furthermore, each square wave of the signal is characterized by a voltage amplitude, which is in particular between 0 and 5V.

[0126] Therefore, reference Figure 7, shows one example of an output signal. Thus, the output signal represents the distribution of a virtual target for camshaft 15. In this example, each initial moment corresponds to a rising edge of a square wave. Therefore, each upward-pointing square wave represents a tooth in the virtual target for camshaft 15.

[0127] Therefore, the virtual target includes twelve evenly distributed teeth and a thirteenth reference tooth, because the thirteenth reference tooth corresponds to a predefined reference angular position. These thirteen teeth have a time width of 45 μs. The voltage amplitude is limited to 5 volts.

[0128] In addition, reference Figure 8 , shows another embodiment of the output signal, which represents the virtual target distribution of the camshaft 15. In this example, each initial moment corresponds to a falling edge of the square wave. Therefore, each downward-pointing square wave represents a recess in the virtual target of the camshaft 15.

[0129] Therefore, the virtual target includes thirteen concave portions, twelve of which are evenly distributed, and one reference concave portion corresponding to a predefined reference angular position. These thirteen concave portions have a time width of 45 μs. The voltage amplitude is limited to 5 volts.

[0130] Transmission E5

[0131] The method comprises a step E5 of transmitting the output signal generated by the camshaft sensor 25 to the computer 20 via a connector of the camshaft sensor 25 dedicated to communication with the computer 20 .

[0132] Therefore, the computer 20 receives the output signal and determines the angular position of the camshaft 15 based on the received output signal.

[0133] The computer can also determine the rotational speed of the camshaft 15 .

[0134] To this end, the computer 20 detects a reference square wave (in other words a reference tooth or a reference recess) corresponding to a predefined reference angular position. Finally, the computer 20 determines at all times the angular position of the camshaft 15 relative to the detected reference square wave.

[0135] Thus, the camshaft sensor 25 makes it possible to determine a virtual target profile of the camshaft 15 based on the measurement of the magnetic field generated by the magnetic element 150 fixed to said camshaft 15. Said virtual target profile can be analyzed by a computer known to those skilled in the art in order to determine the angular position of the camshaft 15 and in particular the rotational speed of the camshaft 15 and thus control the synchronization between at least one camshaft 15 and the crankshaft 13.

Claims

1. A method for generating an output signal, the method being implemented by a sensor (25) for a motor vehicle (1), the vehicle (1) comprising a combustion engine (10) and an engine control computer (20), the engine (10) comprising at least one drive shaft (15) capable of being driven in rotation, the at least one drive shaft (15) having at least one magnetic element (150), the sensor (25) being intended to be arranged facing the at least one magnetic element (150), the computer (20) being configured to determine the angular position of the at least one drive shaft (15) relative to a predefined reference angular position based on the output signal provided by the sensor (25), the method being characterized in that it comprises the following steps: i. measuring the magnetic field generated by the at least one magnetic element (150) passing in front of the sensor (25) as the drive shaft (15) rotates, ii. Generate the cosine component (Bx) and sine component (By) of the measured magnetic field, iii. generating an intermediate signal based on the cosine component (Bx) and the sine component (By), the intermediate signal giving the absolute angular position (a1) of the drive shaft, iv. Generate a square wave output signal by associating each initial moment with an absolute angular position (a1) of the generated intermediate signal, wherein each square wave is characterized by an initial moment and a time width, and the absolute angular position corresponds to a predefined angular position of the drive shaft (15) in one full rotation of the drive shaft (15).

2. A computer program product, characterized in that It has a set of program code instructions which, when executed by one or more processors, configure the one or more processors to implement the method as claimed in claim 1 .

3. A sensor (25) for a motor vehicle (1), the vehicle (1) comprising a combustion engine (10) and an engine control computer (20), the engine (10) comprising at least one drive shaft (15) capable of being driven in rotation, the at least one drive shaft (15) having at least one magnetic element (150), the sensor (25) being intended to be arranged facing the at least one magnetic element (150), the computer (20) being configured to determine the angular position of the at least one drive shaft (15) relative to a predefined reference angular position based on an output signal provided by the sensor (25), the sensor (25) being characterized in that it is capable of: i. measuring the magnetic field generated by the at least one magnetic element (150) passing in front of the sensor (25) as the drive shaft (15) rotates, ii. Generate the cosine component (Bx) and sine component (By) of the measured magnetic field, iii. generating an intermediate signal based on the cosine component (Bx) and the sine component (By), the intermediate signal giving the absolute angular position (a1) of the drive shaft (15), iv. generating a square wave output signal of the sensor (25) by associating each initial moment with an absolute angular position (a1) of the generated intermediate signal, wherein each square wave is characterized by an initial moment and a time width, the absolute angular position corresponding to a predefined angular position of the drive shaft in one full revolution of the drive shaft (15).

4. The sensor (25) according to claim 3, wherein each initial moment represents a rising edge or a falling edge of a square wave.

5. A vehicle (1) comprising a combustion engine (10) and an engine control computer (20), the engine (10) comprising at least one drive shaft (15) capable of being driven in rotation, the at least one drive shaft (15) having at least one magnetic element (150), the vehicle (1) being characterized in that it comprises a sensor (25) as claimed in any one of claims 3 or 4, the sensor (25) measuring the absolute angular position of the drive shaft (15), the computer (20) being configured to determine the angular position of the at least one drive shaft (15) relative to a predefined reference angular position based on a square wave output signal provided by the sensor (25).

6. The vehicle (1) according to claim 5, wherein The magnetic element (150) is a magnet including two poles and is fixed to one end of the drive shaft (15).

7. The vehicle (1) according to any one of claims 5 and 6, wherein The magnetic element (150) is in the form of a metal disc which is fixed to a flat surface at the end of the drive shaft (15).

8. The vehicle (1) according to any one of claims 5 and 6, wherein The vehicle is a motor vehicle.

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