Method for controlling a five-stroke engine of a vehicle.

Abstract

The present invention relates to a method for controlling a five-stroke engine (2) of a vehicle (1), comprising the implementation by data processing means (11) of a computer (10) of steps of: Receiving, from a sensor (3) equipping the vehicle (1), a value of at least a first operating parameter of the five-stroke engine (2); Determining optimized values ​​of at least a second operating parameter of the five-stroke engine (2), using a simulation model of a four-stroke engine (2') calculating the values ​​of at least one parameter representative of the performance of said simulated four-stroke engine (2') as a function of the values ​​of said operating parameters, in which, for each connecting rod (21) of the five-stroke engine (2), the simulated four-stroke engine (2') includes a corresponding virtual connecting rod (21') having a variable length so as to reproduce the operation of the five-stroke engine (2);Application of the determined value(s) of the second operating parameter(s) of said five-stroke engine (2). [Fig. 1a];

Description

Title of the invention: Method for controlling a five-stroke engine of a vehicle. [0001 ] GENERAL TECHNICAL FIELD

[0002] The present invention relates to the field of internal combustion engines. More specifically, it relates to a method for controlling a five-stroke engine of a vehicle.

[0003] STATE OF THE ART

[0004] To achieve the energy transition, particularly in the field of mobility, hydrogen engines are being developed.

[0005] These engines are internal combustion (or "explosion") engines using dihydrogen as fuel instead of a hydrocarbon. Indeed, the combustion of dihydrogen normally produces only water and not CO2. These engines should not be confused with electric motors which would be powered by a fuel cell (hydrogen).

[0006] However, the conventional piston engine is not very suitable for the combustion of gaseous hydrogen. In fact, the temperature rises sharply and the formation of nitrogen oxides (NOx, from nitrogen in the air mixed with dihydrogen) and notorious pollutants is observed, or even problematic self-ignition ("knocking") which degrades performance.

[0007] To solve these problems, a new type of internal combustion engine was developed: the five-stroke engine.

[0008] While a conventional engine is four-stroke (intake, compression, expansion, exhaust), a five-stroke engine also has a fifth "cooling" stroke for the combustion chamber which makes it possible to avoid the aforementioned problems, and proves to be very efficient.

[0009] To further improve its efficiency, it is desirable, like all modern internal combustion engines, to equip it with a computer allowing it to be controlled in operation, i.e. to optimize its operating parameters, such as ignition timing, fuel injection flow rate, supercharging parameters, etc.

[0010] To do this, the computers simulate the operation of the engine according to its configuration and the operating conditions, and optimize the value of said operating parameters so as to maximize the performance of the engine.

[0011] The problem is that existing simulators are designed for four-stroke engines, and prove unsuitable for the five-stroke engine, because the operating paradigm is too different.

[0012] There is therefore currently no solution for effectively optimizing the operating parameters of a five-stroke engine.

[0013] One could of course design a new calculator for a five-stroke engine from a blank page, but it would be long and complex, and its effectiveness would not be guaranteed.

[0014] The present invention improves this situation. PRESENTATION OF THE INVENTION

[0015] The present invention therefore relates, according to a first aspect, to a method for controlling a five-stroke engine of a vehicle, comprising the implementation by data processing means of a step calculator of: a. Reception, from a sensor fitted to the vehicle, of a value of at least one first operating parameter of the five-stroke engine; b. Determining optimized values ​​of at least one second operating parameter of the five-stroke engine, using a simulation model of a four-stroke engine calculating the values ​​of at least one parameter representative of the performance of said simulated four-stroke engine as a function of the values ​​of said operating parameters, wherein, for each connecting rod of the five-stroke engine, the simulated four-stroke engine comprises a corresponding virtual connecting rod having a variable length so as to reproduce the operation of the five-stroke engine; c. Application of the determined value(s) of the second operating parameter(s) to said five-stroke engine.

[0016] According to advantageous and non-limiting characteristics:

[0017] The five-stroke engine comprises a rotating real crankshaft and, for each real connecting rod, a real cylinder and a real piston translating in the real cylinder, the real connecting rod being of fixed length and connecting the real crankshaft to the real piston.

[0018] The simulated four-stroke engine comprises a rotating virtual crankshaft and, for each virtual connecting rod, a virtual cylinder and a virtual piston translating in the virtual cylinder, the virtual connecting rod of variable length connecting the virtual crankshaft to the virtual piston.

[0019] The real crankshaft is of the epicyclic type, while the virtual crankshaft is of the conventional type.

[0020] For each real connecting rod, the variable length of said corresponding virtual connecting rod is such that for any angle of the virtual crankshaft, the displacement of the virtual piston in the virtual cylinder is equal to the displacement of the real piston in the real cylinder, at the same angle of the real crankshaft.

[0021] For each real connecting rod, the variable length 1' of said corresponding virtual connecting rod is expressed as a function of the angle 0 of the virtual crankshaft by the formula r(0)=l+f4(0)-f5(0), where 1 is the fixed length of the real connecting rod, f5(0) is the displacement of the real piston in the real cylinder, and f4(0) is the displacement that the virtual piston would have in the virtual cylinder if the real connecting rod length were fixed and equal to the length of the real connecting rod.

[0022] Said displacement that the virtual piston would have in the virtual cylinder if the real connecting rod length were fixed and equal to the real connecting rod length, is a sinusoidal displacement of a four-stroke engine piston.

[0023] Step (b) comprises, for any angle of the virtual crankshaft, the following sub-steps:

[0024] (bl) calculating the length of each virtual connecting rod as a function of the angle of the virtual crankshaft;

[0025] (b2) implementing said four-stroke engine simulation model using said calculated length of the virtual connecting rods.

[0026] Step (b2) comprises updating the length of the virtual connecting rods as a parameter of said four-stroke engine simulation model.

[0027] Said five-stroke engine includes intake, compression, expansion, exhaust and cooling strokes.

[0028] Said five-stroke engine is a hydrogen engine.

[0029] The at least one first operating parameter is a parameter representative of the operating environment or a parameter imposed by the vehicle such as a target power.

[0030] The at least one second operating parameter is selected from ignition timing, fuel injection rate, and boost parameters.

[0031] According to a second aspect, the invention relates to a computer of a five-stroke engine vehicle, characterized in that it comprises data processing means configured to: - Receive, from a sensor fitted to the vehicle, a value of at least one first operating parameter of the five-stroke engine; - Determining optimized values ​​of at least one second operating parameter of the five-stroke engine, using a simulation model of a four-stroke engine calculating the values ​​of at least one parameter representative of the performance of said simulated four-stroke engine as a function of the values ​​of said operating parameters, in which, for each connecting rod of the five-stroke engine, the simulated four-stroke engine comprises a corresponding virtual connecting rod having a variable length so as to reproduce the operation of the five-stroke engine; - Apply the determined value(s) of the second operating parameter(s) to said five-stroke engine.

[0032] According to a third aspect, the invention relates to a five-stroke engine vehicle comprising a computer according to the second aspect.

[0033] According to a fourth and a fifth aspect, the invention provides a computer program product comprising code instructions for executing a method according to the first aspect of controlling a five-stroke engine of a vehicle; and a storage means readable by computer equipment on which is recorded a computer program product comprising code instructions for executing a method according to the first aspect of controlling a five-stroke engine of a vehicle. PRESENTATION OF FIGURES

[0034] Other characteristics and advantages of the present invention will appear on reading the following description of a preferred embodiment. This description will be given with reference to the appended drawings in which:

[0035] [Fig. la]la [Fig.la] is a diagram of a system for implementing the method according to the invention;

[0036] [Fig.lb] [Fig.lb] is a diagram of a real engine and a virtual engine;

[0037] [Fig.2] [Fig.2] represents the volume of the cylinder over two revolutions of the crankshaft for a five-stroke engine and a four-stroke engine, respectively in solid line and dotted line.

[0038] [Fig.3] [Fig.3] is a flowchart illustrating the steps of an embodiment of the method according to the invention.

[0039] [Fig.4] [Fig.4] represents the valve openings over two crankshaft revolutions for a five-stroke engine. DETAILED DESCRIPTION

[0040] Architecture

[0041] The present invention relates to a method for controlling a five-stroke engine 2 of a vehicle 1, in a system as shown in [Fig.la].

[0042] The vehicle 1 is typically a land vehicle, wheeled or tracked, such as a car, a truck, etc. It will be understood that it could alternatively be a ship, an airplane, etc. The engine 2 is for the propulsion of the vehicle 1.

[0043] Said five-stroke engine 2 is an internal combustion engine, generally hydrogen, either pure or dual-fuel hydrogen / diesel, hydrogen / bioethanol, hydrogen / B100. B100 is a fuel composed of up to 100% fatty acid methyl esters, well known to those skilled in the art. Note that the engine 2 could be gasoline, although five-stroke operation is particularly suited to hydrogen which causes a high temperature rise.

[0044] With reference to [Fig. 1b], said engine 2 comprises, like any internal combustion engine, at least one assembly of a piston 20, a connecting rod 21 and a cylinder 22. Said assemblies share a crankshaft 23. In each assembly, the connecting rod 21 connects the crankshaft 23 to the piston 20 so as to transform a continuous rotational movement of the crankshaft 23 into an alternating translational movement of the piston 20 in the cylinder 22. The end of the cylinder defines a combustion chamber for the fuel (typically hydrogen). Note that said piston 20, connecting rod 21, cylinder 22 and crankshaft 23 of the engine 2 will be called "real" as opposed to virtual equivalents which will be described later.

[0045] As explained previously, a five-stroke engine includes, in addition to the four classic strokes (intake, compression, expansion, exhaust), a fifth "cooling" stroke for the combustion chamber which makes it possible to avoid the aforementioned problems, and proves to be very efficient.

[0046] With reference to [Fig.2], which represents the volume of the cylinder 22 and therefore the displacement of the piston 20 (the two quantities are proportional) as a function of the angle of the crankshaft 23 (over 720°, i.e. 2 revolutions) of the five-stroke engine 2, each stroke lasts approximately 144° crankshaft, and we notice over the interval [630°, 90°] substantially a plateau, which corresponds to this fifth stroke: the piston 20 hardly moves any more, which allows the air to circulate in the cylinder 22 and gives the chamber time to cool. In addition, as during cooling the intake and exhaust valves are open at the same time, we end up with valves open for approximately 288° crankshaft. (These values ​​are variable depending on the opening advances and closing delays that we define according to our combustion).By contrast, in a four-stroke engine the piston displacement is sinusoidal (with each stroke over 180° crankshaft), see the dotted curve in [Fig.2].

[0047] To achieve such a movement, a five-stroke engine comprises, for example, an epicyclic mechanism (called planetary-satellite): the crankshaft 23 acts as a planet carrier and the connecting rod foot 21 is articulated on an eccentric linked to the satellite. It then describes a conchoidal trajectory of a circle which allows the observed slowing down.

[0048] The engine 2 further advantageously comprises conventional equipment of an internal combustion engine such as pipes, valves, injectors, manifolds, a turbocharger, etc.

[0049] As will be seen, it is further assumed that the vehicle 1 (and potentially directly the engine 2) is equipped with at least one sensor 3 of a first operating parameter of the engine 2 (see below).

[0050] Furthermore, the vehicle 1 further comprises a computer 10 for implementing the present method, called an “engine computer”. Conventionally, this computer is a small computer connected to the engine 2 and to the sensor 3, comprising data processing means 11 such as a processor, and generally data storage means 12 such as a memory.

[0051] Principle

[0052] The present method aims to control the engine 2 in operation, that is to say to adapt the values ​​of certain of its operating parameters while it is running (i.e. while the vehicle 1 is running). By control, as explained, is meant the determination and application of adequate values ​​of said operating parameters to the engine 2, so as to change its behavior for example to react to different operating conditions. It is implemented by the data processing means 11 of the computer 10 of the vehicle 1. To reformulate, the computer 10 has the role of managing the values ​​of the operating parameters of the engine 2.

[0053] It is assumed that engine 2 has three types of parameters, each being in all cases a technical physical quantity associated with engine 2: - at least one engine configuration parameter 2, which is a parameter predefined at the design stage, and which applies to both a five-stroke engine and a four-stroke engine. These include the type of fuel, the number of cylinders 22, a type of architecture (in-line or V), the diameter of each cylinder 22 (bore), the maximum distance traveled by each piston 20 (stroke), the compression ratio, the displacement volumes / dead volume, maps and type of turbocharger, the maximum flow characteristics of the injectors, the volume of the manifolds, the diameters of the pipes, etc. These are the parameters that physically define the engine 2 and all its components; we also speak of a structural parameter. It is understood that such a configuration parameter could only vary in the event of mechanical intervention on the engine, and would involve a reconfiguration of the process. - at least one first and at least one second operating parameter. As opposed to structural parameters, operating parameters are variable parameters, representative of the environment in which the engine 2 operates (operating conditions) and of the controls applied to it. A distinction is made between: • the first parameter(s), which are undergone parameters (input parameter in the present method), in particular either external parameters typically representative of the operating environment (for example the external temperature of the engine), or parameters imposed by the vehicle 1, in particular a target power. • the second parameter(s), which are, on the contrary, controllable operating parameters, which can be adjusted, and which the present method will seek to optimize (output parameter). To reformulate, the object of the present method is to determine and apply optimal values ​​of the second operating parameter(s). Preferably, the second parameter(s) are chosen from ignition timing, fuel injection flow rate, and supercharging parameters. - finally, at least one parameter representative of the performances, which is a parameter relating to a predefined criterion making it possible to evaluate the engine 2. Preferably this criterion is the energy efficiency and / or the emissions, so that this parameter can be the fuel consumption, the quantities produced of C02 / N0x, etc.

[0054] In a known manner, a simulation of the engine 2 will be implemented so as to determine values ​​of the second parameter(s) making it possible to optimize (i.e. maximize / minimize as appropriate, or at least respect expected thresholds) the parameter(s) representative of the performance, for given values ​​of the first parameter(s).

[0055] It will be understood that the present method is not limited to any combination of operating parameters / performance representative parameters, as long as these are physical quantities linked to the engine 2 with a technical interest. Limiting oneself to certain parameters would unduly limit the scope of the present application, especially since a great many strategies for optimizing operating parameters have been known for a long time.

[0056] Indeed, the object of the present method is not a new strategy for optimizing parameters by simulations, but a trick allowing the agnostic use of a four-stroke engine simulator to simulate a five-stroke engine. Thus, a high-performance simulator can be reused in a simple and efficient manner. This makes it possible to minimize the work required to obtain a calculator for a five-stroke engine, while having guarantees on its performance.

[0057] Method

[0058] In this respect, with reference to [Fig.3], the method begins with a step (a) of reception (by the data processing means 11), from a sensor 3 equipping the vehicle 1, of a value of at least a first operating parameter of the engine 2.

[0059] This step must be understood broadly as encompassing either directly the acquisition of the values ​​of said first parameters (for example the temperature acquired by a thermometer-type sensor 3), or the determination of said values ​​from the raw data of the sensor 3 (for example, the sensor 3 may be the accelerator pedal sensor, and the first parameter a target power determined from the level of depression of the accelerator pedal).

[0060] Again, this is well known to those skilled in the art and will not be re-discussed.

[0061] Then, in a main step (b), the means 11 determine values optimized of the second operating parameter(s) of the engine 2, using a simulation model of a four-stroke engine 2'.

[0062] In this respect, said simulator calculates the values ​​of the parameter(s) representative of the performance of said simulated engine 2' as a function of the values ​​of said operating parameters.

[0063] This is a step of optimization under constraint of the values ​​of the second operating parameters, using the simulator to predict the value of the parameters representative of the performance of the engine 2 for candidate values ​​of the second operating parameters.

[0064] It is important to understand that the real engine 2 is a five-stroke, while the simulated engine 2', called a virtual engine, is a four-stroke. We can therefore use any existing four-stroke engine simulator, for example AMEsim, configured with the engine configuration parameters mentioned above (whether the engine is a four-stroke or five-stroke, the values ​​of these parameters do not change except possibly those linked to the valve opening phases, see below), and any known optimization algorithm.

[0065] Thus, the simulated four-stroke engine 2' comprises for each real component 20, 21, 22, 23 of the real engine 2, a virtual equivalent 20', 21', 22', 23', as seen in [Fig.2],

[0066] More precisely, the simulated engine 2' comprises a rotating virtual crankshaft 23' and, for each piston 20, connecting rod 21 and cylinder 22, respectively a virtual piston 20', a virtual connecting rod 21' and a virtual cylinder 22'. The virtual piston 20' is therefore in translation in the virtual cylinder 20', the virtual connecting rod 21' connecting the virtual crankshaft 23' to the virtual piston 20'. For each real member 20, 21, 22, 23, the "corresponding" virtual member 20', 21', 22', 23' in the simulated engine 2' will be designated. It is recalled that the real crankshaft 23 is typically of the epicyclic type (which allows an "irregular" movement of the piston 20 and thus the fifth stroke), while the virtual crankshaft 23' is a "classic" crankshaft of a four-stroke engine (which causes a sinusoidal movement of the virtual piston 20').

[0067] The trick is that, for each connecting rod 21 of the five-stroke engine 2, the corresponding virtual connecting rod 21' has a variable length so as to reproduce the operation of the five-stroke engine 2. To rephrase, during the simulation the length of the virtual connecting rods 21' will vary in real time, which will modify the displacement of the virtual pistons 20' (we will no longer have the classic sinusoidal displacement) and make it possible to simulate a five-stroke engine. We understand that this is to trick the simulator: of course, there is no connecting rod of variable length in reality, neither in a four-stroke engine nor in a five-stroke engine, and no simulator is designed to dynamically manage this length (the length of the connecting rod is supposed to be entered as a configuration parameter among others - i.e. present a fixed value, and not be a signal).

[0068] This is thus a matter of artificially altering the operation of the simulator, because if the variable length is correctly chosen we will see that the simulator will simulate a five-stroke engine instead of a four-stroke engine in spite of itself, and this in a completely agnostic manner. We repeat that the simulation itself is done in an unchanged manner, the simulator not being bothered by this variable length although it is absolutely not provided for, and allowing it to operate in a normal manner.

[0069] More precisely, if we return to [Fig.2], it is a question, starting from the sinusoidal curve of a 4-stroke engine, of modifying the length of the virtual connecting rod 21' as a function of the crankshaft angle 23 / 23' so as to find the more complex curve of the five-stroke engine.

[0070] To reformulate, for each real connecting rod 21, the variable length of said corresponding virtual connecting rod 21' is such that, for any angle of the virtual crankshaft 23', the displacement of the virtual piston 20' in the virtual cylinder 22' is equal to the displacement of the real piston 20 in the real cylinder 22, at the same angle of the real crankshaft 23'.

[0071] Mathematically, we assume that we have: - a first function d5=f5(0), where d5 is the displacement of the real / virtual piston 20 / 20' and 0 the angle of the real / virtual crankshaft 23 / 23' modulo 720° (which is not necessarily a defined function, we can just have a list of the values ​​of d for each value of 0); - a second function d4=f4(0), where d4 is the displacement of the piston of a four-stroke engine (i.e. the displacement that the virtual piston 20' would have if the virtual connecting rod 21' were of constant length), which is preferably a sinusoidal function, typically of the form f4(0)=a*sin(0 / 2)+b, with a and b predefined constants; - by noting 1 the (fixed) length of the real connecting rod 21 and 1' the (variable) length of the virtual connecting rod 21', we can express the latter as a function of 0 as l'(0)=lA(0), where A is the observed displacement difference d-d', i.e. l'(0)=l+f4(0)-f5(0). Indeed, because we use a virtual connecting rod 21' of variable length, the observed displacement noted d4' becomes d4'= d4+(l-l'). And since we require that the displacement of the virtual piston 20' in the virtual cylinder 22' be equal to the displacement of the real piston 20 in the real cylinder 22, at the same angle of the real crankshaft 23', ie d5= d4', ie f5(0)= f4(0)+(l-l'), hence r(0)=i+f4(0)-f5(O).

[0072] It is therefore sufficient, during step (b), to “reparameterize” at each time step the length of the virtual connecting rod 21' in the simulator.

[0073] In this respect, step (b) advantageously comprises, for any angle 0 of the virtual crankshaft 23' (and in practice for any time step, the angle 0 being recalculated at each time step as a function of time, knowing the rotation speed of the crankshaft) two sub-steps. First of all, there is a step (bl) of calculating the length of each virtual connecting rod 21' as a function of the angle of the virtual crankshaft 23'. This typically involves applying the above formula.

[0074] Then, in a step (b2) said simulation model of the four-stroke engine 2' is implemented using said calculated lengths of the virtual connecting rods 21' and the other predefined configuration parameters. As explained, this step is generally implemented continuously, step (b) comprising in practice the updating of the length of the virtual connecting rods 21' as a parameter of said simulation model of the four-stroke engine 2'. In other words, at each time step the value of the connecting rod length parameter in the simulator is corrected, which makes this parameter dynamic and therefore makes it possible to obtain the variable nature of the virtual connecting rod length 21'.

[0075] The only other difference that can possibly be foreseen in the parameterization of the simulation model is that of the valve opening phases, because the valve opening time as well as the scavenging time (which corresponds to the additional cooling time) are much longer on the five-stroke engine. In the context of this engine, it should be noted that the opening of the intake port is spread over two consecutive times, as shown in [Fig.4] (representing the intake and cooling times). Similarly, the opening of the exhaust port takes place over two consecutive times (exhaust and cooling). This configuration differs from the classic configuration of the four-stroke engine, where each valve traditionally opens during a specific phase. We can therefore directly configure the simulation model so as to apply a valve opening control law adapted to the five-stroke engine, or even optimize some of its parameters as second operating parameters.

[0076] As explained, step (b) includes an optimization aspect: the simulator makes it possible to predict the values ​​of the parameters representative of the performances for candidate values ​​of the second operating parameters. These candidate values ​​are then dynamically tested until optimized values ​​are found which allow the best values ​​of the parameters representative of the performances (for example the lowest CO2 / NOx emissions), or at least those which are sufficiently good (respecting a given criterion, for example below a legal emissions threshold). Again, any optimization technique of any existing simulator may be used, the invention relating to the idea of ​​introducing the virtual connecting rod 21' of variable length and not a simulation / optimization strategy per se.We can therefore use the existing calculators, just adding the calculation block for the variable length depending on the crankshaft angle and applying it in the simulator.

[0077] Finally, in a final step (c) which is again conventional, the method comprises applying the determined values ​​of the second operating parameter(s) to said five-stroke engine 2. In other words, the computer 10 imposes the determined values ​​of the parameters on the real engine 2, because it is known from the simulation model that they will make it possible to achieve the expected values ​​of the parameters representative of the performances (and therefore the corresponding performance level). This is therefore a step in which the operation of the engine 2 and therefore the vehicle 1 are physically acted upon.

[0078] Calculator and vehicle

[0079] According to a second aspect, the invention relates to the calculator 10 for implementing the method according to the first aspect.

[0080] The computer 10 is therefore that of a vehicle 1 with a five-stroke engine 2, and it comprises data processing means 11 and generally data storage means 12.

[0081] The data processing means 11 are configured to: - Receive, from a sensor 3 fitted to the vehicle 1, a value of at least a first operating parameter of the five-stroke engine 2; - Determine optimized values ​​of at least one second operating parameter of the five-stroke engine 2, using a simulation model of a four-stroke engine 2' calculating the values ​​of at least one parameter representative of the performance of said simulated four-stroke engine 2' as a function of the values ​​of said operating parameters, in which, for each connecting rod 21 of the five-stroke engine 2, the simulated four-stroke engine 2' comprises a corresponding virtual connecting rod 21' having a variable length so as to reproduce the operation of the five-stroke engine 2; - Apply the determined value(s) of the second operating parameter(s) to said five-stroke engine 2.

[0082] According to a third aspect, the invention relates to a vehicle 1 (with a five-stroke engine 2) comprising the computer 10 for controlling the five-stroke engine 2. The vehicle 1 further comprises the sensor(s) 3.

[0083] Computer program product

[0084] According to a fourth and a fifth aspect, the invention relates to a computer program product comprising code instructions for the execution (on the data processing means 11 of the computer 10) of a method according to the first aspect of controlling a five-stroke engine 2 of a vehicle 1; and a storage means (for example the data storage means 12 of the computer 10) on which this computer program product is found.

Claims

Claims

1. Method for controlling a five-stroke engine (2) of a vehicle (1), comprising the implementation by data processing means (11) of a computer (10) of steps of: a. Receiving, from a sensor (3) fitted to the vehicle (1), a value of at least one first operating parameter of the five-stroke engine (2); b. Determining optimized values ​​of at least one second operating parameter of the five-stroke engine (2), using a simulation model of a four-stroke engine (2') calculating the values ​​of at least one parameter representative of the performance of said simulated four-stroke engine (2') as a function of the values ​​of said operating parameters, in which, for each connecting rod (21) of the five-stroke engine (2), the simulated four-stroke engine (2') comprises a corresponding virtual connecting rod (21') having a variable length so as to reproduce the operation of the five-stroke engine (2); c.Application of the determined value(s) of the second operating parameter(s) to said five-stroke engine (2).

2. Method according to claim 1, wherein - the five-stroke engine (2) comprises a real crankshaft (23) in rotation and, for each real connecting rod (21), a real cylinder (22) and a real piston (20) in translation in the real cylinder (22), the real connecting rod (21) being of fixed length and connecting the real crankshaft (23) to the real piston (20), - the simulated four-stroke engine (2') comprises a virtual crankshaft (23') in rotation and, for each virtual connecting rod (21'), a virtual cylinder (22') and a virtual piston (20') in translation in the virtual cylinder (22'), the virtual connecting rod (21') of variable length connecting the virtual crankshaft (23') to the virtual piston (20').

3. Method according to the preceding claim, in which the real crankshaft (23) is of the epicyclic type, while the virtual crankshaft (23') is of the conventional type.

4. Method according to one of claims 2 and 3, in which, for each real connecting rod (21), the variable length of said virtual connecting rod (21') is such that for any angle of the virtual crankshaft (23'), the displacement of the virtual piston (20') in the virtual cylinder (22') is equal to the displacement of the real piston (20) in the real cylinder (22), at the same angle of the real crankshaft (23).

5. Method according to claim 4, wherein, for each real connecting rod (21), the variable length 1' of said corresponding virtual connecting rod (21') is expressed as a function of the angle 0 of the virtual crankshaft (23') by the formula r(0)=l+f4(0)-f5(0), where 1 is the fixed length of the real connecting rod (21), f5(0) is the displacement of the real piston (20) in the real cylinder (22), and f4(0) is the displacement that the virtual piston (20') would have in the virtual cylinder (22') if the real connecting rod length (21') were fixed and equal to the length of the real connecting rod (21).

6. A method according to claim 5, wherein said displacement that the virtual piston (20') would have in the virtual cylinder (22') if the actual connecting rod length (21') were fixed and equal to the length of the actual connecting rod (21), is a sinusoidal displacement of a four-stroke engine piston.

7. Method according to one of claims 2 to 6, in which step (b) comprises, for any angle of the virtual crankshaft (23'), the following sub-steps: (bl) calculating the length of each virtual connecting rod (21') as a function of the angle of the virtual crankshaft (23'); (b2) implementing said simulation model of the four-stroke engine (2') using said calculated length of the virtual connecting rods (21')

8. A method according to claim 7, wherein step (b2) comprises updating the length of the virtual connecting rods (21') as a parameter of said simulation model of the four-stroke engine (2').

9. A method according to one of claims 1 to 8, wherein said five-stroke engine (2') comprises intake, compression, expansion, exhaust and cooling strokes.

10. A method according to one of claims 1 to 9, wherein said five-stroke engine (2') is a hydrogen engine.

11. Method according to one of claims 1 to 9, in which the at least one first operating parameter is a parameter representative of the operating environment or a parameter imposed by the vehicle (1) such as a target power; and / or ...

12.

13.

14.

15. at least one second operating parameter is selected from ignition timing, fuel injection rate, and boost parameters. Computer (10) of a vehicle (1) with a five-stroke engine (2), characterized in that it comprises data processing means (11) configured to: - Receive, from a sensor (3) fitted to the vehicle (1), a value of at least a first operating parameter of the five-stroke engine (2); - Determining optimized values ​​of at least one second operating parameter of the five-stroke engine (2), using a simulation model of a four-stroke engine (2') calculating the values ​​of at least one parameter representative of the performance of said simulated four-stroke engine (2') as a function of the values ​​of said operating parameters, in which, for each connecting rod (21) of the five-stroke engine (2), the simulated four-stroke engine (2') comprises a corresponding virtual connecting rod (21') having a variable length so as to reproduce the operation of the five-stroke engine (2); - Apply the determined value(s) of the second operating parameter(s) to said five-stroke engine (2). Vehicle (1) comprising a computer (10) according to claim 12. Computer program product comprising code instructions for executing a method according to one of claims 1 to 11 for controlling a five-stroke engine (2) of a vehicle (1), when said program is executed on a computer. Storage medium readable by computer equipment on which is recorded a computer program product comprising code instructions for the execution of a method according to one of claims 1 to 11 for controlling a five-stroke engine (2) of a vehicle (1).