Estimating the degree of corrosion in injectors

Abstract

The present invention relates to a method for estimating the degree of corrosion of an injector of an engine, the engine comprising a reference injector and at least one other injector, each injector comprising a tip in fluidic communication with a combustion chamber dedicated to the injector, the corresponding combustion chamber of each injector also being in fluidic communication with an exhaust system of the engine. The method comprises the following steps: - when the engine is stopped, inhibiting the propagation of gas from the exhaust system toward the tip of the reference injector; - determining a static flow rate of the injector and a static flow rate of a reference injector; - estimating the degree of corrosion of the injector by comparing the static flow rate of the injector with the static flow rate of the reference injector.

Description

Technical Field

[0001] The present invention relates to a method for estimating the degree of corrosion of an injector of an injection engine. The present invention is particularly applicable to the automotive industry. Background Art

[0002] Conventionally, an injection engine comprises an injector provided with an injection hole and a rail for supplying fuel to the injector. These injectors are adapted to inject fuel into the cylinder through the hole, and the fuel is subjected to a determined pressure in the rail by means of a high-pressure pump.

[0003] These injectors are subject to corrosion and clogging phenomena due to their use. This application is particularly concerned with the phenomenon of corrosion.

[0004] Corrosion of the injector causes the injector's orifice to enlarge, sometimes causing the injector's static flow to increase and thereby changing the amount injected by the injector.

[0005] Furthermore, corrosion can unevenly attack the various holes in the injector, which can affect the atomization of the fuel in the cylinder and lead to increased pollutant emissions even if the injected amount varies only slightly.

[0006] In fact, it is possible that the injector is both clogged and corroded. Since these phenomena compensate for each other, it is not possible to determine the degree of corrosion or clogging of the injector by simply referring to the injection volume of the injector or its static flow rate using known methods.

[0007] In particular, there is no known method that enables the degree of corrosion of an injector to be estimated regardless of the injector type, be it a solenoid injector or a piezo injector. Summary of the Invention

[0008] Therefore, a first object of the present application is to propose a method for estimating the degree of corrosion of an injector in an engine.

[0009] The second objective is to estimate the corrosion extent without adding additional sensors, which would significantly increase the complexity of the system.

[0010] The third purpose is to trigger an alarm when the corrosion level of the injector becomes too high.

[0011] A fourth objective is to evenly distribute the corrosion level of multiple injectors among the injectors.

[0012] In this regard, the present application describes a method for estimating the degree of corrosion of an injector of an engine, the engine comprising a reference injector and at least one other injector, each injector comprising a tip in fluid communication with a combustion chamber dedicated to each injector, the respective combustion chamber of each injector also being in fluid communication with the exhaust system of the engine,

[0013] The method is characterized in that it comprises the following steps:

[0014] - inhibiting the propagation of gases from the exhaust system towards the tip of the reference injector when the engine is stopped,

[0015] - determine the static flow rate of the injector and the static flow rate of the reference injector,

[0016] - Estimating the degree of corrosion of the injector by comparing the static flow rate of the injector with the static flow rate of a reference injector.

[0017] According to an alternative, the step of inhibiting the propagation of gases consists in closing each exhaust valve corresponding to a reference injector.

[0018] According to an alternative, the method comprises the additional step of generating an alarm when the degree of corrosion of the injector is greater than a determined threshold value.

[0019] According to an alternative, the engine comprises a plurality of injectors, and the steps of determining the static flow rate of an injector and estimating the degree of corrosion of said injector are carried out for each of the plurality of injectors of the engine.

[0020] The above-described estimation method advantageously allows for accurate estimation of the degree of corrosion of one or more injectors of an engine by using a non-corroded reference injector. This estimation is independent of variations in fuel quality and / or temperature, as the reference injector is subjected to the same operating conditions as the other injectors. Furthermore, the method does not require additional sensors, and thus the degree of injector corrosion can be determined without further complicating the injection system.

[0021] The present application also describes a method for distributing corrosion levels among a plurality of injectors of an engine, the engine also including a reference injector, each injector including a tip in fluid communication with a combustion chamber dedicated to each injector, the respective combustion chamber of each injector also being in fluid communication with an exhaust system of the engine,

[0022] The method is characterized in that it comprises the following steps:

[0023] When executed on a plurality of injectors, a method for estimating the extent of corrosion is implemented, and

[0024] The engine is stopped so that the exhaust valve corresponding to the injector having the lowest corrosion degree estimation result among the plurality of injectors is opened.

[0025] The method for distributing the degree of corrosion thus makes it possible to distribute the corrosion among the various injectors of the engine without adding additional sensors, which consequently makes it possible to extend the life of the injection system without making it more complex.

[0026] The present application is also directed to a computer program product comprising code instructions allowing the implementation of the above-mentioned method steps.

[0027] The present application also describes a computer suitable for controlling an engine comprising a reference injector and at least one other injector, each injector comprising a tip in fluid communication with a combustion chamber dedicated to each injector, the respective combustion chamber of each injector also being in fluid communication with an exhaust system of the engine,

[0028] The computer is characterized in that it is adapted to perform the following steps:

[0029] - inhibiting the propagation of gases from the exhaust system towards the tip of the reference injector when the engine is stopped,

[0030] - determine the static flow rate of the injector and the static flow rate of the reference injector,

[0031] - Estimating the degree of corrosion of the injector by comparing the static flow rate of the injector with the static flow rate of a reference injector.

[0032] According to an alternative, the engine comprises a plurality of injectors and the computer is adapted to perform the steps of determining a static flow rate of the injector and estimating a degree of corrosion for each of the plurality of injectors of the engine.

[0033] In this alternative, the computer may be further adapted to control the engine to stop such that the exhaust valve associated with the injector having the lowest estimated corrosion level among the plurality of injectors is opened.

[0034] Finally, the present application discloses an engine comprising a reference injector and at least one other injector, each injector comprising a tip in fluid communication with a combustion chamber dedicated to each injector, the respective combustion chamber of each injector also being in fluid communication with the exhaust system of the engine, the engine also comprising a computer according to one of the above-described alternatives. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Other features, details, and advantages will become apparent upon reading the following detailed description and analyzing the accompanying drawings, in which:

[0036] [ Figure 1 ] presents a flow chart of an embodiment of a method for estimating the degree of corrosion of an injector;

[0037] [ Figure 2 ] An embodiment of an engine is presented in which a method for estimating the degree of corrosion is implemented.

[0038] [ Figure 3 ] shows a flow chart of an embodiment of a method for distributing corrosion levels among multiple injectors. DETAILED DESCRIPTION

[0039] Now refer to [ Figure 2 ], which shows that it allows implementation for estimating [ Figure 1 ] is an embodiment of an engine of the method for determining the degree of corrosion of an injector. In this case, [ Figure 2 ] The engine is not shown in its entirety.

[0040] Advantageously, the engine may be on a motor vehicle such as a car or truck.

[0041] In this case, the engine includes a reference injector 2 r and at least one other injector 2. Advantageously, the engine comprises a reference injector 2 r and multiple injectors 2, such as Figure 2 As shown. Injector (2,2 r ) is in fluid communication with a high pressure fuel supply rail, which is in fluid communication with a high pressure fuel supply rail at [ Figure 2 ] is not shown.

[0042] Each injector includes a combustion chamber (3,3 r ) a tip (21, 21) of the fluid communication r ). The tip of each injector includes a plurality of holes (not shown) so that fuel passing from the supply rail through the injector can be delivered through these holes into the combustion chamber. It is these holes that are subject to corrosion, so that as the injector is used, the diameter of these holes increases.

[0043] Corresponding to each injector (2,2 r ) combustion chamber (3,3 r ) is in fluid communication with the exhaust system 4 of the engine. The exhaust system 4 of the engine makes it possible to discharge exhaust gases generated by the combustion of fuel in the combustion chamber.

[0044] The engine also includes at least one exhaust valve (41, 41 r ), the exhaust valve and each combustion chamber (3,3 r )(and thus with each injector (41, 41 r )) is associated with the exhaust valve, which is arranged in such a way that when it is closed, it cuts off the fluid communication between the combustion chamber and the exhaust system 4 of the engine.

[0045] It should be understood here that when the combustion chamber (3,3 r ) associated exhaust valve is opened, the injector (2, 2 r ) tip (21, 21 r ) is connected to the exhaust system 4 fluid.

[0046] Now refer to [ Figure 1 ] describes a method for estimating the corrosion degree of an injector 2 of an engine. The problem here is based on the injector 2 and the reference injector 2 r The comparison between the two determines the corrosion degree of the injector 2. The method can be implemented by a computer (not shown), which has a memory storing code instructions for implementing the method. Of course, the code instructions can be stored in any other memory accessible to the computer.

[0047] In the case where the engine is on board a vehicle, the method may be carried out by a computer on board the vehicle, and advantageously by a computer known as an Engine Control Unit (ECU).

[0048] The method comprises a first step carried out when the engine is stopped. This is to inhibit 110 the flow of gas from the exhaust system 4 to the reference injector 2 r Tip 21 r Steps of propagation.

[0049] The inventors have noticed that the corrosion phenomenon of the injector hole is closely related to the presence of corrosive gases in the engine exhaust system after the engine stops. However, as mentioned above, the exhaust system is in fluid communication with the tip of the injector through the exhaust valve.

[0050] Suppress 110 gas from exhaust system 4 to reference injector 2 r Tip 21 r This step of propagation thus makes it possible to protect the reference injector 2 r In this way, in addition to the corrosion phenomenon, the reference injector 2 r Under the same operating conditions as the other injectors 2 of the engine, it can be compared with the other injectors 2 of the engine in order to determine their respective corrosion levels. In other words, the reference injector 2 r Used to isolate the corrosive properties present on other injectors.

[0051] The suppression 110 may be achieved, for example, by shutting down the injector corresponding to the reference injector 2. r Each exhaust valve 41 r In this case, a person skilled in the art who is familiar with the engine model will be able to implement this step. As previously mentioned, closing the exhaust valve associated with the injector combustion chamber makes it possible to cut off the fluid communication between the injector combustion chamber and the engine exhaust system, and therefore also cut off the fluid communication between the injector tip located in this combustion chamber and the engine exhaust system.

[0052] The second step of the method comprises determining 120 the static flow rate of the injector 2 and the reference injector 2 rStatic flow rate of an injector. The static flow rate of an injector is understood here to be the fuel flow rate delivered by the injector into its combustion chamber at a certain fuel pressure when the injector is fully open. Numerous methods known to those skilled in the art make it possible to estimate the static flow rate of an injector. For example, there are methods based on measuring the vacuum observed in the fuel supply rail during injection, or on analyzing signals from a crankshaft sensor or a concentration sensor. Other methods use sensors, such as those that make electrical contact between the needle and the injector tip, or cylinder pressure sensors in the combustion chamber. All methods for estimating the static flow rate of an injector can be used here.

[0053] As previously mentioned, as injector erosion causes the diameter of the injector's orifice to increase, the static flow rate of the injector increases because more fuel can pass through the injector's orifice for a given supply pressure.

[0054] In this regard, as the injectors 2 are used, the static flow rate of the injectors 2 that experience erosion relative to the reference injectors 2 r The static flow rate is different due to the suppression step 110, reference injector 2 r Static flows do not experience corrosion phenomena.

[0055] Advantageously, for determining the static flow of the injector 2 and the reference injector 2 r The method for static traffic is the same.

[0056] Therefore, the third step of the method consists in comparing the static flow of said injector 2 with that of a reference injector 2 r The static flow rate of the injector 2 is compared with the reference injector 2 to estimate the corrosion degree of the injector 2. As mentioned above, the static flow rate of the injector 2 is compared with the reference injector 2. r The static flow rate is different because the reference ejector 2 r No corrosion will occur. r ) are under the same operating conditions except for the corrosion characteristics, so the comparison of their respective static flow rates makes it possible to obtain the corrosion degree of the injector 2 by methods known to those skilled in the art. In addition, since the two injectors (2, 2 r ) are under the same operating conditions, so this method overcomes all problems related to the quality and / or temperature of the fuel to estimate the corrosion level of the injector 2.

[0057] For example, for a given injector model, the degree of corrosion may be obtained from a correspondence table that relates the degree of corrosion to the difference between the static flow rate of a non-corroded injector and the static flow rate of a corroded injector.

[0058] In embodiments comprising a plurality of injectors 2, it will be appreciated that the static flow rate of each injector may also be calculated by comparing the static flow rate of each injector to the reference injector 2. r The static flow rate is compared to estimate the corresponding corrosion degree of each injector.

[0059] It should also be understood that the same method is used to estimate the injector 2 and the reference injector 2 r The static flow rate makes it possible to obtain a more accurate degree of corrosion of the injector 2.

[0060] Furthermore, the method may comprise the additional step of generating 140 an alarm when the estimated degree of corrosion of the injector 2 is greater than a determined threshold value. For example, when the engine is on the vehicle, the alarm may comprise a warning to the driver that he must replace an injector 2 whose degree of corrosion is greater than the aforementioned threshold value.

[0061] It will therefore be appreciated that the method described above makes it possible to estimate in an accurate manner the degree of corrosion of one or more injectors of an engine. This accurate estimation can be achieved by comparing the injector 2 with a reference injector 2 without corrosion. r Since the latter is subjected to the same operating conditions as the other injectors 2, the proposed estimation of the degree of corrosion is independent of variations in the quality and / or temperature of the fuel. Furthermore, the estimation of the degree of corrosion according to the present invention can be implemented in existing systems, thus avoiding the need for additional sensors and, consequently, additional complexity and cost of the system.

[0062] The invention also proposes a method which makes it possible to distribute the degree of corrosion among a plurality of injectors 2 in an engine as described above. Figure 3 ] describes the method, and the method is implemented by a computer.

[0063] In this case, the method for distributing the degree of corrosion among a plurality of injectors 2 of an engine comprises implementing 210 the first step of the method for estimating the degree of corrosion described above when executing the method on a plurality of injectors 2 .

[0064] Therefore, the method for distributing the degree of corrosion between the injectors 2 is advantageously implemented by the same computer as the computer implementing the method for estimating the degree of corrosion, in order to avoid the transmission of data from the estimation results of the degree of corrosion of the injectors 2 .

[0065] At the end of this step, the computer thus has the degree of corrosion for each of the plurality of injectors 2 .

[0066] The method then comprises a second step of stopping 220 the engine so that each exhaust valve 41 of the injector 2 presenting the lowest corrosion level estimation result 130 among the plurality of injectors 2 is opened.

[0067] As previously mentioned, corrosion is caused by stagnation of exhaust gas at the tip of the injector 2 after the engine stops. Therefore, preventing the exhaust gas from appearing at the tip of the injector can prevent the injector from being corroded. Therefore, conversely, the injector with the least corrosion among the plurality of injectors 2 is selected, and its tip is exposed to an environment where exhaust gas exists by opening the corresponding exhaust valve, so that corrosion can be targeted to the injector 2 with the least corrosion. However, considering the conventional operation of the engine, when the exhaust valve 41 corresponding to this injector 2 (more precisely, the exhaust valve 41 of the combustion chamber 3 in which the tip of the injector 2 diffuses fuel) is opened, the exhaust valve 41 of the other injectors (2, 2) is opened. r ) associated exhaust valve (41, 41 r ) is closed and therefore protected from corrosion when the engine is stopped. Thus, it is possible to select which injector will be corroded by the exhaust gas after the engine is stopped 220 while protecting the other injectors.

[0068] In the same manner as described above, a person skilled in the art who understands the engine model can implement this step so that when the user requests the engine to stop, the engine still rotates sufficiently before stopping to allow the exhaust valve 41 of the combustion chamber 3 associated with the target injector 2 to open.

[0069] This method thus makes it possible to distribute the degree of corrosion among a plurality of injectors 2 of an engine, according to the estimation method and engine control steps described above, without adding any additional components and thus without increasing the manufacturing and integration costs of said engine. By distributing the negative effects of corrosion uniformly across all the injectors, this makes it possible to extend the life of the injection system without complicating it.

Claims

1. A method for estimating the degree of corrosion of an injector (2) of an engine, said engine comprising a reference injector (2 r ) and at least one other injector (2), each injector (2, 2 r ) includes a combustion chamber (3,3 r ) a tip (21, 21) of the fluid communication r ), each injector (2,2 r ) of the corresponding combustion chamber (3,3 r ) is also in fluid communication with the exhaust system (4) of said engine, The method is characterized in that it comprises the following steps: - when the engine is stopped, inhibiting (110) the flow of gas from the exhaust system (4) to the reference injector (2 r ) of the tip (21 r )spread, - determining (120) the static flow rate of the injector (2) and the reference injector (2 r ) of the static flow, - by comparing the static flow rate of the injector (2) with the reference injector (2 r )’s static flow rate is compared to estimate (130) the corrosion degree of other injectors (2).

2. Method for estimating the degree of corrosion according to the preceding claim, characterized in that The step of suppressing (110) the propagation of gas comprises closing the injector corresponding to the reference injector (2 r ) of each exhaust valve (41 r ).

3. The method for estimating the degree of corrosion according to claim 1 or 2, characterized in that: When the degree of corrosion of the injector (2) is greater than a determined threshold value, the method comprises the additional step of generating (140) an alarm.

4. The method for estimating the degree of corrosion according to claim 1 or 2, characterized in that: The engine comprises a plurality of other injectors (2), and the steps of determining (120) the static flow of the injector (2) and estimating (130) the degree of corrosion of the injector (2) are performed for each injector (2) of the plurality of injectors (2) of the engine.

5. A method for distributing the degree of corrosion among a plurality of other injectors (2) of an engine, The method is characterized in that it comprises the following steps: implementing (210) the method for estimating the degree of corrosion as claimed in claim 4, and The engine (220) is stopped so that the exhaust valve (41) corresponding to the injector (2) having the lowest corrosion degree estimation result (130) among the plurality of other injectors (2) is opened.

6. A computer program comprising program code instructions for performing the steps of the method as claimed in any one of the preceding claims when the computer program is executed on a computer.

7. A computer adapted to control an engine comprising a reference injector (2 r ) and at least one other injector (2), each injector (2, 2 r ) includes a combustion chamber (3,3 r ) a tip (21, 21) of the fluid communication r ), each injector (2,2 r ) of the corresponding combustion chamber (3,3 r ) is also in fluid communication with the exhaust system (4) of said engine, The computer is characterized in that it is adapted to perform the following steps: - when the engine is stopped, inhibiting (110) the flow of gas from the exhaust system (4) to the reference injector (2 r ) of the tip (21 r )spread, - determining (120) the static flow rate of the injector (2) and the reference injector (2 r ) of the static flow, - by comparing the static flow rate of the injector (2) with the reference injector (2 r ) by comparing the static flow of the other injectors (2) to estimate (130) the corrosion degree of the other injectors (2).

8. Computer according to the preceding claim, characterized in that The engine comprises a plurality of other injectors (2), and the computer is adapted to perform the steps of determining (120) the static flow of the injector (2) and estimating (130) the degree of corrosion of each of the plurality of injectors (2) of the engine.

9. Computer according to the preceding claim, characterized in that It is also suitable for controlling the engine stop (220) so that the exhaust valve (41) associated with the injector (2) having the lowest corrosion level estimation result (130) among the plurality of injectors (2) is opened.

10. An engine comprising the computer according to any one of claims 7 to 9.

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