METHOD AND SYSTEM FOR VALIDATING THE PHASE OF A VEHICLE ENGINE

Abstract

The present invention relates to a method for determining the configuration of an internal combustion engine of a motor vehicle comprising a step (E1) of detecting the reference position of the crankshaft, a step (E2) of controlling the control valve of the injection pump, after a predetermined time interval, a step (E5) of measuring a value of fuel pressure in the injection rail, and a step (E6) of determining a first engine configuration when the value of fuel pressure measured in the injection rail is greater than or equal to a first predetermined pressure threshold or determining a second engine configuration when the value of fuel pressure measured in the injection rail is between a second predetermined pressure threshold and a third predetermined pressure threshold.

Description

Figure 2 is a schematic view of the system in Figure 1 detailing the vehicle's engine. Figure 3 is a schematic view of the system in Figure 1 detailing the injection module. Figures 4A to 4C schematically illustrate an example of the operation of a piston pump actuated by a cam comprising three lobes. Figure 5 graphically illustrates the evolution of the position of the piston in the high-pressure pump during half of an engine cycle as a function of an open and closed state of the control valve connected to the injection pump, allowing fuel injection into the injection rail. Figure 6 schematically illustrates one embodiment of the process according to the invention. The invention will be presented below with a view to implementation in a motor vehicle. However, any implementation in a different context, in particular for any vehicle comprising an internal combustion engine whose configuration needs to be determined, is also covered by the invention. Similarly, the invention will be described by means of an example in which the fuel injection into a combustion chamber is synchronized with the opening of the intake valve connected to that same intake chamber, that is to say, during the intake phase of that combustion chamber; however, such synchronization could also be achieved during another phase of operation, depending on the type of engine concerned. 1 / System With reference to Figure 1, the system 1, according to one representation of the invention, comprises a motor vehicle combustion engine 10, an injection module 20 and a control module for the injection module 20, here in the form of a computer 30. a. Engine 10 As schematically represented in Figure 2, the combustion engine 10 comprises, in a known manner, a plurality of cylinders 11, each delimiting a combustion chamber 11A in which slides a piston 12 whose movement is driven by compression and expansion of the gases resulting from the compression of a mixture of air and fuel introduced into the combustion chambers 11A. As a reminder, air and gases are respectively introduced and expelled via intake valves 14A and exhaust valves 14B, connected in this example to a single camshaft 15. However, the vehicle's engine 10 could just as easily include two camshafts 15, one dedicated to the intake valves 14A and the other to the exhaust valves 14B. Similarly, in this For example, each cylinder 11 is connected to an intake valve 14A and an exhaust valve 14B; however, each cylinder 11 could also be connected to several intake valves 14A and several exhaust valves 14B. The camshaft 15, when rotated, alternately opens and closes the intake and exhaust valves 14 of each combustion chamber 11A. The piston assembly 12 is connected to a crankshaft 13, whose rotation, achieved by the thrust of each piston 12, allows the vehicle's wheels to rotate. The crankshaft 13 includes a gear 130 with a predetermined number of evenly spaced teeth, as well as a gap in the teeth corresponding to a reference position Do of the crankshaft 13. Since such a gear 130 is known in itself, it will not be described in further detail here. A position sensor 16 is mounted opposite the toothed wheel 130 so as to allow the detection of the reference position Do and the counting of the number of teeth passing in front of the position sensor 16 from the reference position Do by the control unit 30 when the crankshaft 13 is rotated. More specifically, the position sensor 16 delivers a signal representing the passage of the teeth, which allows the control unit 30 to determine the angular position of the crankshaft 13 from 0° to 360°. Alternatively, the position sensor 16 could itself detect the reference position Do, count the teeth, and send this information to the control unit 30 without limiting the scope of the present invention. When the camshaft 15 and crankshaft 13 are rotated, the camshaft 15 completes one full rotation from 0° to 360°, resulting in the crankshaft 13 completing two rotations. This is commonly referred to as an engine cycle ranging from 0° to 720°, during which four operating phases are carried out for each of the combustion chambers 11A, for example, in turn. Indeed, each combustion chamber 11A of the cylinders 11 of the engine 10 successively comprises the following operating phases: an intake phase of air and fuel into the combustion chamber 11A, a compression phase of the mixture until its combustion, an expansion phase of the gases resulting from such combustion and an exhaust phase of the gases out of the combustion chamber 11A. b. Injection module 20 The injection module 20 allows fuel to be introduced into the combustion chambers 11 A. In this example, the system 1 according to the invention allows the timing of fuel injection into a combustion chamber 11A to be synchronized with the opening of the intake valve 14A of that same chamber. 11 combustion 11 A. However, depending on the type of engine, the timing of fuel injection could just as well be synchronized with another phase of the combustion chamber 11 A, for example at the end of the combustion phase. To achieve this synchronization, the injection module 20 is connected to the computer 30, for example the main computer of the vehicle, and includes, with reference to Figure 3, an injection pump 21, configured to pump fuel into an injection rail 22, connected to a plurality of injectors 23. The injection module 20 further includes a control valve 24 for the opening and closing of the injection pump 21 and a pressure sensor 25. Preferably, the injection pump 21 includes one or more internal piston(s) 210 (not shown), usually a piston 210, configured to control the fuel flow, thereby regulating the pressure in the injection module 20. To achieve this, as shown in Figures 4A, 4B, and 4C, a piston 210 slides smoothly within the injection pump 21. The piston 210 is thus configured to move smoothly within the injection pump 21, allowing fuel to be introduced (Figure 4A) into the injection pump 21 and then expelled (Figure 4B). With the control valve 24 open, the injection pump 21 is not pressurized. Fuel is introduced into the injection pump 21 via a control valve 24, which opens and closes the pump, thus controlling the fuel flow. When the control valve 24 is open, as shown in Figures 4A and 4B, the movement of the piston 210 causes fuel to be introduced and delivered without any pressure increase in the injection pump 21. However, when the control valve 24 is closed, as shown in Figure 4C, the piston 210 compresses the fuel introduced into the injection pump 21, increasing the pressure. This causes a connecting valve 211 to open, leading to fuel being introduced into the injection rail 22 and thus increasing the pressure in the injection rail 22. Such a control valve 24 is preferably a digital flow valve, allowing more precise control of the fuel flow in the injection pump 21 and thus regulation of the pressure in the injection rail 22. Moreover, in this example, the control valve 24 is included in the injection pump 21; however, it is understood that the control valve 24 could be external to the injection pump 21, as shown in Figure 3. In a preferred embodiment, the sliding movement of the piston 210 in the injection pump 21 is driven by a cam 150 of the shaft to 12 cams 15 rotating. However, the injection pump 21 could just as easily include a rotary piston 210 comprising a plurality of lobes. In this example, the number of lobes of the rotary piston 210 would be odd. Indeed, in a preferred embodiment of the invention, during an engine cycle from 0° to 720°, the injection pump 21 is configured to allow fuel to be injected into the injection rail 22 an odd number of times. For example, the piston 210 of the injection pump 21 is configured to pump fuel three times during the engine cycle. The succession of six sliding strokes (for example, three upward and three downward strokes) of the piston 210 during an engine cycle thus allows three pressure increases in the injection pump 21, and therefore three pressure increases in the injection rail 22, during that engine cycle. The injection pump 21 is configured to operate synchronously with the crankshaft 13. In particular, the injection pump 21 is configured to build up pressure, by means of the control valve 24, synchronously with one or more defined positions of the crankshaft 13. Indeed, during an engine cycle, the crankshaft 13, making two revolutions, the position sensor 16 is configured to detect the reference position Do twice. In this example, when the control valve 24 is closed, the cam 150 actuating the piston 210 of the three-lobed injection pump 21, the first reference position Do of the crankshaft 13 corresponds to a high position of the piston 210 and therefore to an increase in pressure in the injection pump 21 and thus in the injection rail 22, while the second reference position Do corresponds to a low position of the piston 210 and therefore to a constant fuel pressure value P in the injection rail 22. Such an injection rail 22 is configured to allow the distribution of fuel, from the injection pump 21, into all the cylinders 11 of the engine 10 via injectors 23. The injector 23 of the combustion chamber 11A, whose intake valve 14A is open, is activated so as to allow, in this example, the simultaneous admission of the air and fuel mixture into the combustion chamber 11A. To enable the implementation of the invention, the injection module 20 includes a pressure sensor 25, connected to the injection rail 22 and configured to measure a pressure value P in the injection rail 22. Such a pressure sensor 25 is configured to transmit the pressure measurement values ​​P to the vehicle's computer 30. Indeed, with reference to Figure 5, during its operation, the position Z of the piston 210 of the injection pump 21 alternates successively between a high position H and a low position B. When the control valve 24 is closed (OFF), the high position H of the piston 210 corresponds to a first phase h of fuel injection into the injection rail 22 during which the pressure in the injection rail 22 increases and the low position B to a second phase l2 during which the fuel is not compressed in the injection pump 21, not resulting in fuel injection into the injection rail 22 in which the pressure then remains constant. Indeed, when the control valve 24 is open, the pressure in the injection pump 21, and therefore in the injection rail 22, corresponds to a minimum pressure designated as the predetermined initial pressure Pi, which is generally close to atmospheric pressure. When the control valve 24 is closed, two cases arise: if the piston 210 of the injection pump 21 is in the low position B, i.e., the fuel is not compressed by the piston 210, then the pressure value P in the injection rail 22 is equivalent to the predetermined initial pressure Pi; similarly, if the piston 210 is in the high position H, i.e., the fuel is compressed by the piston 210, then the pressure value P in the injection pump 21, and therefore in the injection rail 22, is greater than the predetermined initial pressure Pi. In this example, in which the piston 210 of the injection pump 21 is configured to pump fuel three times during a complete engine cycle, the first and second turns of the crankshaft 13, each corresponding to half of an engine cycle, thus each correspond to a different position of the piston 210. Indeed, when the control valve 24 is closed, if the crankshaft 13 is in its first rotation, then the piston 210, synchronized with the crankshaft 13, is configured to be in the first phase h of rising to the high position H, in which the pressure value P measured in the injection rail 22 is greater than the predetermined initial pressure Pi.Similarly, if the crankshaft 13 is in its second rotation, then the piston 210 is configured to be in the second phase l2 of descent in the low position B, in which the pressure value P measured in the injection rail 22 is similar to the predetermined initial pressure Pi. By similar, we mean in this example that the pressure value P is equal to the predetermined initial pressure Pi ± 1 MPa (Megapascal). The odd number of phases h during which the piston 210 pumps fuel into the injection rail 22 during a complete engine cycle thus makes it possible to ensure that the fuel pressure in the injection rail 22 is different for the same angular position of the crankshaft 13 during two consecutive revolutions of said crankshaft 13, corresponding to two different configurations of the engine 10. c. Calculator 30 The control unit 30, for example the vehicle's main control unit, controls the fuel injection into a defined combustion chamber 11A at a precise moment. To this end, the control unit 30 is configured to operate the control valve 24 in order to control the fuel flow into the injection pump 21 and to control the closure of such injection pump 21, allowing fuel to be introduced into the injection rail 22. In other words, the control unit 30 is configured to control the pumping of fuel into the injection rail 22 via the injection pump 21, which is controlled by the control valve 24, at a given moment corresponding to the predetermined position of the crankshaft 13, known and described previously. The vehicle's computer 30 is finally configured to receive the data provided by the crankshaft position sensor 16 13 and by the pressure sensor 25 in the injection rail 22. 2 / Process The invention will now be described in an example of implementation with reference to Figures 5 and 6. The method for determining the position of the crankshaft 13 makes it possible to determine the synchronization of the engine 10. The crankshaft 13 and the camshaft 15 being connected in such a way as to allow simultaneous rotation, such a method could equivalently be described by determining the position of the camshaft 15, the position of which can be known by means of the position sensor 16 of the crankshaft 13. In this example, the process first includes a step E0 of starting up the engine 10, enabling the rotation of the camshaft 15 and crankshaft 13 to be activated. An initial pressure value Pi is then measured in the injection rail 22 using the pressure sensor 25. The position sensor 16 then detects, in step E1A, the reference position DOa of the crankshaft 13 by detecting the free space between teeth on the gear 130. A signal indicating the detection of a tooth on the gear 130 is then regularly sent to the control unit 30. In this example, the position sensor 16 detects each tooth of the gear 130 and regularly transmits a tooth presence detection signal to the control unit 30. The control unit 30 then detects the reference position Do of the crankshaft 13 when no signal is sent by the position sensor 16 for a predetermined period. However, it is understood that the position sensor 16 could just as easily directly detect the reference position Do of the crankshaft 13 and 15 transmit a detection signal of such a reference position Do to the computer 30 for example. When the control unit 30 detects the reference position D0A of the crankshaft 13, it commands, for example, the closure of the control valve 24 in a step E2A. Alternatively, the closure of the control valve 24 can be commanded by the control unit 30 after a predetermined time interval, depending on the mounting of the injection pump 21. The control unit 30 then detects, in a step E3A, an angular rotation of the crankshaft 13, designated as the offset DA of the angular position of the crankshaft 13, from the reference position Doa. Such an offset DA of the angular position of the crankshaft 13 is between 30° and 240°, preferably 120° in the example of an engine operating by means of a starter and thus rotating at a speed of 300 rpm, and corresponds to a time interval.The calculator 30 could thus also trigger a time delay T whose duration corresponds to a predetermined time interval, for example 10 milliseconds. As shown in the graph in the figure, this time delay T corresponds to the time elapsed between the detection of the reference position Do and the instant when the piston 210 of the injection pump 21 is in the upper position H. In an E4A step, the pressure sensor 25 measures the pressure in the injection rail 22 and transmits the measured pressure PA value to the computer 30. Thus, when the computer 30 commands the control valve 24 of the injection pump 21 so that said injection pump 21 injects fuel into the injection rail 22, the value PA of fuel pressure in the injection rail 22, measured at the end of the shift DA of the angular position of the crankshaft 13, has increased to reach a maximum if the engine 10 is in a first configuration, or has remained constant, if the engine 10 is in a second configuration. The PA pressure value is then compared to the predetermined initial pressure value Pi in step E5A. When the pressure value PA measured in step E4A is greater than a predetermined first threshold Si, for example equal to the predetermined initial pressure Pi plus at least 3 MPa, preferably 10 MPa, then the computer 30 deduces, in a step E6A, that the engine 10 is in the first configuration, i.e., that the crankshaft 13 is indeed in its first revolution. The engine 10 is synchronized (Y). When the pressure value PA measured in step E4A is between a predetermined second threshold S2 and a predetermined third threshold S3, then the computer 30 deduces, in this step E6A, either that the engine 10 is in the 16. Second configuration, i.e., the crankshaft 13 is in its second revolution, meaning the engine 10 is out of sync and exhibits an anomaly (W). In this example, the second predetermined threshold S2 and the third predetermined threshold S3 correspond respectively to the predetermined initial pressure Pi decreased by 1 MPa and the predetermined initial pressure Pi increased by 1 MPa. In other words, the measured pressure value PA is said to be similar to the predetermined initial pressure Pi, i.e., for example, equal to the predetermined initial pressure Pi ± 1 MPa. In this latter case, the process then includes a further step E1B for detecting the second reference position D0B of the crankshaft 13, corresponding to the next revolution of the crankshaft 13, followed by a further step E2B for closing the control valve 24. After a second shift DB of the angular position of the crankshaft 13 or a second predetermined time interval (step E3B), the pressure in the injection rail 22 is measured again in a further step E4B and compared to the predetermined initial pressure Pi in a further step E5B. If the measured pressure value PB is greater than or equal to the first predetermined threshold Si, then the engine is indeed in its first configuration, i.e., the crankshaft 13 is indeed in its first revolution. The process includes a step E6B for validating the synchronization of the engine 10 (Y).If the measured pressure value PB is less than the first predetermined threshold Si, then the process detects that the motor 10 is out of sync and has an anomaly (N). This method advantageously determines the crankshaft position and thus the engine's operating phase, allowing engine synchronization without the need for fuel injection. The method according to the invention therefore limits deterioration of the exhaust system and reduces vehicle emissions.

Claims

17 DEMANDS 1. Method for determining the configuration of a combustion engine (10) of a motor vehicle, said vehicle comprising an internal combustion engine (10) having three cylinders (11), a fuel injection rail (22) in said cylinders (11), a high-pressure hydraulic injection pump (21) capable of pumping 5 fuel in said injection rail (22), a control valve (24) for opening and closing said injection pump (21), a pressure sensor (25) for measuring the fuel pressure flowing in said injection rail (22), and a control module (30), said engine (10) further comprising a crankshaft (13) characterized by its angular position relative to a reference position (Do) and at least one camshaft (15) integrally connected to said crankshaft (13) such that the crankshaft (13) completes two full revolutions when at least one camshaft (15) completes one full revolution, said injection pump (21) comprising at least one fuel-pumping piston (210) and being mounted synchronously with said crankshaft (13) such that said at least one piston (210) pumps fuel an odd number of times during a turn of said at least one camshaft (15),said process being characterized in that it comprises: • a step (E1a) of detecting the reference position (Do) of the crankshaft (13), • a control step (E2a), by the control module (30), of the closing of the control valve (24) of the injection pump (21), 20 • after a first predetermined time interval, a measurement step (E4a), by the pressure sensor (25), of a value (P) of fuel pressure in the injection rail (22), • a step (E5a) of comparing the value (P) of fuel pressure measured in the injection rail (22) with a predetermined initial pressure value (Pi) 25, and • a step (E6a) of determining a first engine configuration (10) when the value (P) of fuel pressure measured in the injection rail (22) is greater than or equal to a first predetermined pressure threshold (Si) or of determining a second engine configuration (10) 30 when the value (P) of fuel pressure measured in the rail injection (22) is between a second predetermined pressure threshold (S2) and a third predetermined pressure threshold (S3).

2. A method according to the preceding claim, wherein the value (P) of fuel pressure measured in the injection rail (22) is between said the second predetermined pressure threshold (S2) and said third predetermined pressure threshold (S3), the process comprises: • after a second predetermined time interval, a new control step (E4b) of the control valve (24) of the injection pump (21), • a further measurement step (E5b), by the pressure sensor (25), of a value (Pb) of fuel pressure in the injection rail (22), and • a step (E6b) of determining the first engine configuration (10) when the value (PB) of fuel pressure measured in the injection rail (22) is greater than or equal to said first threshold (Si) of predetermined pressure or of detecting an engine anomaly, when the value (Pb) of pressure measured in the injection rail (22) is less than the first threshold (Si) of predetermined pressure.

3. A method according to any one of the preceding claims, wherein the first predetermined threshold (Si) corresponds to the predetermined initial pressure (Pi) increased by at least 3 MPa, preferably increased by 10 MPa.

4. A method according to any one of the preceding claims, wherein the second predetermined threshold (S2) and the third predetermined threshold (S3) correspond respectively to the predetermined initial pressure (Pi) reduced by 1 MPa and to the predetermined initial pressure (Pi) increased by 1 MPa.

5. Method according to any one of the preceding claims, comprising, prior to the step (E1) of detecting the reference position (Do) of the crankshaft (13), a preliminary step (E0) of measuring said initial pressure value (Pi) in said injection rail (22).

6. A method according to any one of the preceding claims, wherein said at least one piston (210) of the injection pump (21) pumps fuel an odd number of times during one revolution of said at least one camshaft (15), each cam of said camshaft (15) comprising an odd number of lobes.

7. A method according to any one of the preceding claims, wherein the first time interval is between 20 and 500 ms, preferably 70 ms.

8. A method according to any one of the preceding claims, wherein the second time interval is between 50 and 500 ms, preferably 200 ms.

9. System (1) for determining the position of a crankshaft (13) of an internal combustion engine (10) of a motor vehicle, comprising: • an internal combustion engine (10) comprising a plurality of cylinders (11), a crankshaft (13) characterized by its angular position from a position of reference (Do), at least one camshaft (15) securely connected to said crankshaft (13) so that the crankshaft (13) completes two full revolutions when said at least one camshaft (15) completes one full revolution, and a position sensor (16) capable of determining the angular position of said crankshaft (13), • an injection module (20) comprising: - a high-pressure fuel injection pump (21) comprising at least one fuel-pumping piston (210) and mounted in a synchronized manner with said crankshaft (13) such that said at least one piston (210) pumps fuel an odd number of times during one revolution of said at least one camshaft (15), - a control valve (24) configured to control the opening and closing of said injection pump (21), - a fuel injection rail (22) connected on the one hand to said injection pump (21) and on the other hand to a plurality of injectors (23) allowing the fuel to be injected into the cylinders (11) of the engine (10), - a pressure sensor (25), configured to measure the pressure value (P) in said injection rail (22), • a control module (30) configured to control the opening and closing of said control valve (24) and to determine the position of the crankshaft (13) by means of the position sensor (16) and the pressure sensor (25) in order to determine the configuration of the engine (10).

10. Motor vehicle comprising a system (1) for determining the configuration of an internal combustion engine (10) according to claim 9.

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