BR102018016989A2 - PRESSURE ESTIMATE METHOD ON A CYLINDER OF A COMBUSTION ENGINE, COMBUSTION ENGINE, AND RELATED DEVICES - Google Patents

Abstract

The present invention relates to a method (100) of estimating a pressure in at least one cylinder (3.1 - 3.6) of an internal combustion engine (1), wherein method (100) comprises the steps of selectively opening (110). ) at least one valve (9) in at least one cylinder (3.1 - 3.6) of the internal combustion engine (1), providing a fluid pressure (p) in a fluid chamber (13), measuring (120) the pressure (p) in the fluid chamber (13), and estimate (130) the pressure in at least one cylinder (3.1 - 3.6) based on the measured fluid pressure (p) in the fluid chamber (13). The present disclosure further relates to a computer program, a computer readable medium (200), a control arrangement (23), an internal combustion engine (1) and a vehicle (25) comprising an internal combustion engine. (1).

Description

[0001] This description relates to a method for estimating pressure in at least one cylinder of an internal combustion engine. The present description further relates to a computer program, and a computer program product to execute the method, a control arrangement configured to estimate a pressure in at least one cylinder of an internal combustion engine, a combustion engine internal, and a vehicle.

BACKGROUND OF THE INVENTION [0002] Internal combustion engines, like four-stroke internal combustion engines, comprise one or more cylinders and a piston arranged in each cylinder. The pistons are connected to an engine crankshaft and are arranged to alternate within the cylinders by rotating the crankshaft. The engine usually further comprises one or more inlet valves and one or more outlet valves, as well as one or more fuel delivery arrangements. The one or more inlet and outlet valves are controlled by a respective valve control arrangement, usually comprising one or more cam shafts connected rotatively to a motor crankshaft, through a belt, chain, gears, gear rods. traction or similar. A four-stroke internal combustion engine completes four separate strokes by turning the crankshaft. A stroke refers to the total displacement of the piston along the cylinder, in any direction. The highest position of the piston in the cylinder is generally called the upper dead center TDC, and the lowest position of the piston in the cylinder is generally called the lower dead center BDC.

[0003] The courses are completed in the following order, entry course, compression course, expansion course and escape course. During operation of a conventional four-stroke internal combustion engine, the inlet valve control arrangement controls the inlet valves of a cylinder to an open state during the piston inlet stroke into the cylinder, to allow

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2/29 air or a mixture of air and fuel enter the cylinder. During the compression stroke, all valves must be closed to allow compression of air or the mixture of air and fuel in the cylinder. If the engine is in a state of energy production, the fuel in the cylinder is ignited, usually at the end of the compression stroke, for example, by a spark plug or by compression heat in the cylinder. The combustion of the fuel inside the cylinder significantly increases the pressure and temperature in the cylinder. Combustion of the fuel generally continues for a significant part of the subsequent expansion course. The increase in pressure and temperature in the cylinder obtained by combustion is partially converted into mechanical work supplied to the crankshaft in the expansion stroke. Obviously, all valves must remain closed during the expansion stroke to allow the increase in pressure and temperature to be converted into mechanical work. The expansion course is also generally called the combustion course, because generally, most combustion occurs during the expansion course. In the subsequent exhaust stroke, the exhaust valve control arrangement controls the cylinder's exhaust valves to an open state to allow exhaust gases to be expelled out of the cylinder into an exhaust system.

[0004] During motorization, occurring, for example, when a driver of a vehicle releases the accelerator pedal, the engine will continue to operate on the courses described above, with the exception that, normally, no fuel is supplied to the engine during the motorization and, consequently, no combustion will occur during the end of the compression stroke or during the expansion stroke. In this condition, the engine will provide some braking torque due to internal friction and due to the pumping of air from the intake to the exhaust, in the respective intake stroke and exhaust stroke. As a piston moves upward during the compression stroke, the gases trapped in the cylinder are compressed. The compressed gases are opposed to the piston's upward movement. However, almost all of the energy stored in the compressed gases is returned to the crankshaft in the subsequent expansion course. Thus, during normal motorization, the stroke

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3/29 compression together with the subsequent expansion stroke will not contribute to significant engine braking torque.

[0005] A compression release brake arrangement is an engine braking mechanism used on some engines. When activated, it opens the exhaust valves on the cylinders after the compression stroke, releasing the compressed air trapped in the cylinders to the exhaust system. In this way, the energy stored in the compressed gases during the compression stroke will not be returned to the crankshaft in the subsequent expansion stroke, which increases the engine's braking torque.

[0006] In some arrangements, the exhaust valves can be disabled, so that they remain closed during the exhaust stroke. This is usually accomplished using a so-called lost motion arrangement which, when triggered, is arranged not to transfer movement caused by an exhaust cam lobe to the exhaust valve. The air in the cylinders will thus be compressed also during the exhaust stroke. When using a valve control arrangement that opens the exhaust valves near the end of the exhaust stroke, compressed air trapped in the cylinders is released into the exhaust system. This arrangement almost doubles the braking torque, since the compression and release events are carried out in the compression stroke, as well as in the exhaust stroke.

[0007] In a compression ignition engine, such as a diesel engine, it is the heat of the compressed gases that ignites the fuel. In a spark ignition engine, like an Otto engine, it is a spark plug that ignites fuel. Compression in cylinders is an important factor for engine operation and efficiency. The pressure in the cylinders obtained during compression indicates the compression in the cylinders. Compression in an engine's cylinders can degrade over time because engine components are subject to wear, such as the cylinder, piston, piston rings, valves, valve seats, etc. In addition, in an engine with more than one cylinder, that is, most vehicle engines, one or more of the cylinders can be used unpredictably. In such a situation, the vehicle can be driven many miles before the spent cylinder is noticed, for example, during a

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4/29 maintenance procedure. Even so, even during a maintenance procedure, the worn cylinder may not be noticed, which can cause further damage to the engine.

[0008] The pressure in the cylinders of an engine and, therefore, also the compression of the cylinders, can be measured using a pressure gauge arranged in each cylinder. However, this is an expensive solution to obtain pressure in the cylinders, especially for an engine comprising several cylinders. In addition, due to the irregular environment inside a cylinder of a combustion engine, that is, due to considerable heat, pressure and vibrations in the cylinder, such pressure gauges are likely to be damaged during the life of the engine, which will add more costs. for replacement.

[0009] Thus, the use of pressure gauges arranged in each cylinder is an expensive and sensitive solution to obtain pressure in the cylinders. As a reason, the most common way to determine pressure in cylinders is to perform a manual compression measurement in a workshop using a pressure gauge. Such a procedure is costly and expensive and must be performed individually on each cylinder. In addition, such a procedure does not have the ability to provide instantaneous measurement of pressure in the cylinders, for example, during engine operation. In addition, in most cases, such a procedure is not part of a maintenance schedule and therefore will not be performed if the mechanism appears to work correctly. In addition, many vehicles travel many miles between maintenance intervals. Consequently, the compression of one or more cylinders can degrade significantly before being detected.

SUMMARY OF THE INVENTION [0010] It is an objective of the present invention to overcome, or at least alleviate, at least some of the problems and disadvantages mentioned above.

[0011] According to a first aspect of the invention, the objective is achieved by a method of estimating a pressure in at least one cylinder of an internal combustion engine, where the internal combustion engine comprises:

- at least one cylinder,

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- a piston arranged in each cylinder,

- a crankshaft,

- at least one valve arranged in each cylinder, where at least one valve is arranged to control the flow of gas into and / or out of the cylinder,

- a valve control arrangement comprising a fluid chamber and

- a sensor configured to measure the fluid pressure in the fluid chamber, where the method comprises the steps of:

- selectively open at least one valve on at least one cylinder, providing fluid pressure in the fluid chamber,

- measure the fluid pressure in the fluid chamber, and

- estimate the pressure in at least one cylinder based on the fluid pressure measured in the fluid chamber.

[0012] As the method comprises the step of estimating the pressure in at least one cylinder based on the fluid pressure measured in the fluid chamber, a method is provided that estimates the pressure in at least one cylinder in an efficient, reliable and economical way . In addition, a method is provided capable of estimating the compression of at least one cylinder in an efficient, reliable and economical manner, since the pressure in the cylinder is indicative of the compression in the cylinder. In addition, conditions are provided to obtain an instantaneous estimate of the pressure in at least one cylinder, and the compression of at least one cylinder, for example, during the motorization of the internal combustion engine, in an efficient, reliable and economical way. In addition, as an instantaneous estimate of compression on at least one cylinder can be obtained efficiently, reliably and economically, conditions are also provided to detect whether one or more engine components that are related to the compression of at least one cylinder have been subjected to wear that reduces compression, such as piston, piston rings, at least one valve, valve seats of at least one valve, valve clearance of at least one valve, etc. As a result, this

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6/29 component wear can be detected at an early stage, which reduces the risk of excessive wear of the components as well as other components of the internal combustion engine and therefore potentially reduces the cost of service and repair of the combustion engine internal. In addition, as component wear can be detected at an early stage, the method provides conditions for performing condition-based maintenance on an internal combustion engine.

[0013] Therefore, a method is provided that overcomes, or at least alleviates, at least some of the problems and disadvantages mentioned above. As a result, the goal mentioned above is achieved.

[0014] Optionally, the piston is arranged to alternate in at least one cylinder between a lower dead center and an upper dead center, where the method comprises the step of:

- open at least one valve on at least one cylinder, when the piston is in an upper dead center region.

[0015] In this way, the pressure in the cylinder, and therefore also the compression in the cylinder, can be estimated more precisely, since the pressure in the cylinder is higher when the piston is in a region of the upper dead center, the that when the piston is in a region of the bottom dead center.

[0016] Optionally, the valve control arrangement comprises a valve actuator, and where the fluid chamber is arranged between the valve actuator and at least one valve.

[0017] In this way, the pressure estimation in at least one cylinder can be done in an efficient and reliable way, because the fluid pressure measured in the fluid chamber provides a clear and reliable indication of the pressure in at least one cylinder.

[0018] Optionally, the method is executed during the braking of the internal combustion engine, during the motorization of the internal combustion engine, or during the start of the internal combustion engine. As a result, a method is provided that estimates the pressure in at least one cylinder in an even more

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7/29 efficient and reliable. This is because there is no combustion during engine braking, starting and during engine operation. As an additional result, the compression of at least one cylinder can be estimated even more efficiently and reliably, since the pressure in at least one cylinder, during engine braking, during motorization, as well as during starting , provides a clear indication of the compression of at least one cylinder. In addition, an internal combustion engine in a vehicle performs engine braking, motorization, as well as starting frequently. As a result, the method can be performed frequently, which provides more conditions for detecting component wear at an early stage, thereby further reducing the risk of excessive component wear and thus potentially reducing the cost of engine maintenance and repair. internal combustion.

[0019] Optionally, the internal combustion engine comprises a compression-release brake arrangement comprising the valve control arrangement, where the compression-release brake arrangement is configured to selectively perform the compression-release brake of the engine combustion, and where the method is performed during compression release braking. As a result, a method is provided that estimates the pressure in at least one cylinder in an even more efficient and reliable manner. This is because there is no combustion during the compression release braking. As an additional result of this, the compression of at least one cylinder can be estimated even more efficiently and reliably, since the pressure in at least one cylinder, during compression release braking, provides a clear indication of the compression of at least one cylinder. In addition, a vehicle's internal combustion engine in normal traffic will perform compression release braking frequently. As a result, the method can be performed frequently, which further provides conditions for detecting component wear at an early stage, thereby further reducing the risk of excessive component wear and thus potentially reducing the cost of engine maintenance and repair. internal combustion.

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8/29 [0020] Optionally, the internal combustion engine comprises at least two cylinders and a crank angle sensor, where the method comprises the steps of:

- monitor a series of consecutive pressure rise events for the measured fluid pressure, and

- identify a correlation between one or more consecutive pressure increase events and one of at least two cylinders, comparing the consecutive pressure increase events and the crank angle of the crankshaft. [0021] In this way, it is provided a method capable of identifying the correlation between the estimated pressures and the cylinders, which gives the possibility to identify a cylinder with a deviating cylinder pressure in an engine comprising more than one cylinder. In addition, conditions are provided to estimate the pressure in two or more cylinders of an engine using only one sensor. In this way, it is provided a method capable of estimating the pressure in two or more cylinders of an internal combustion engine, in an efficient, reliable and economical way.

[0022] According to a second aspect of the invention, the objective is achieved by a computer program that comprises instructions that, when the program is executed by a computer, cause the computer to execute the method according to the modalities described here . Since the computer program comprises instructions that, when the program is executed by a computer, cause the computer to execute the method according to the modalities described here, a computer program is provided that provides conditions to overcome, or at least alleviate at least some of the disadvantages mentioned above.

[0023] According to a third aspect of the invention, the objective is achieved by a computer-readable medium comprising instructions that, when executed by a computer, cause the computer to execute the method according to the modalities described here. Since the computer-readable medium comprises instructions that, when the program is executed by a computer, cause the computer to execute the method according to the

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9/29 modalities described herein, a computer-readable medium is provided that provides conditions to overcome, or at least alleviate, at least some of the disadvantages mentioned above.

[0024] According to a fourth aspect of the invention, the objective is achieved by a control arrangement configured to estimate a pressure in at least one cylinder of an internal combustion engine, where the internal combustion engine comprises:

- at least one cylinder,

- a piston arranged in each cylinder,

- a crankshaft,

- at least one valve arranged in each cylinder, where at least one valve is arranged to control the flow of gas into and / or out of the cylinder,

- a valve control arrangement comprising a fluid chamber and

- a sensor configured to measure fluid pressure in the fluid chamber, where the control arrangement is configured to:

- selectively open at least one valve on at least one cylinder, providing fluid pressure in the fluid chamber,

- measure the fluid pressure in the fluid chamber, and

- estimate the pressure in at least one cylinder based on the fluid pressure measured in the fluid chamber.

[0025] Since the control arrangement is configured to estimate pressure in at least one cylinder based on the fluid pressure measured in the fluid chamber, a control arrangement is provided that efficiently estimates pressure in at least one cylinder, reliable and economical. In addition, a control arrangement is provided capable of estimating the compression of at least one cylinder in an efficient, reliable and economical manner, since the pressure in the cylinder is indicative of the compression in the cylinder. In addition, a control arrangement is provided capable of obtaining an instant estimate of the pressure in at least one cylinder, and

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10/29 compression of at least one cylinder, for example, during the motorization of the internal combustion engine in an efficient, reliable and economical way. In addition, as an instantaneous estimate of compression on at least one cylinder can be obtained efficiently, reliably and economically, conditions are also provided to detect whether one or more engine components that are related to the compression of at least one cylinder have been subjected to wear that reduces compression, such as the piston, piston rings, at least one valve, valve seats of at least one valve, valve clearance of at least one valve. As a result, this component wear can be detected at an early stage, which reduces the risk of excessive wear of components, as well as other components of the internal combustion engine, and therefore potentially reduces the cost of engine maintenance and repair. internal combustion. In addition, since component wear can be detected at an early stage, the control arrangement provides conditions for performing condition-based maintenance of an internal combustion engine comprising the control arrangement.

[0026] Consequently, a control provision is provided that overcomes, or at least alleviates, at least some of the problems and disadvantages mentioned above. As a result, the goal mentioned above is achieved.

[0027] According to a fifth aspect of the invention, the objective is achieved by an internal combustion engine comprising:

- at least one cylinder,

- a piston arranged in each cylinder,

- a crankshaft,

- at least one valve arranged in each cylinder, where at least one valve is arranged to control the flow of gas into and / or out of the cylinder,

- a valve control arrangement that includes a fluid chamber,

- a sensor configured to measure the fluid pressure in the fluid chamber and

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- a control arrangement configured for:

- selectively open at least one valve on at least one cylinder, providing fluid pressure in the fluid chamber,

- measure the fluid pressure in the fluid chamber, and

- estimate the pressure in at least one cylinder based on the fluid pressure measured in the fluid chamber.

[0028] As the control arrangement of the internal combustion engine is configured to estimate the pressure in at least one cylinder based on the fluid pressure measured in the fluid chamber, an internal combustion engine is provided capable of estimating the pressure in at least least one cylinder in an efficient, reliable and economical way. In addition, an internal combustion engine is provided capable of estimating the compression of at least one cylinder in an efficient, reliable and economical way, since the pressure in the cylinder is indicative of the compression in the cylinder. In addition, the internal combustion engine is provided capable of obtaining an instant estimate of the pressure in at least one cylinder, and compression of at least one cylinder, for example, during the motorization of the internal combustion engine efficiently, reliably and economically . In addition, as an instantaneous compression estimate on at least one cylinder can be obtained efficiently, reliably and economically, conditions are also provided to detect whether one or more components of the internal combustion engine that is related to the compression of at least one cylinder have been subjected to wear that reduces compression, such as piston, piston rings, at least one valve, valve seats of at least one valve, valve clearance of at least one valve, etc. As a result, this component wear can be detected at an early stage, which reduces the risk of excessive wear of the components, as well as other components of the internal combustion engine, and therefore potentially reduces the cost of servicing and repairing the engine. internal combustion. In addition, since component wear can be detected at an early stage, conditions are provided to perform maintenance based on the condition of the internal combustion engine.

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12/29 [0029] Consequently, an internal combustion engine is provided to overcome, or at least alleviate, at least some of the problems and disadvantages mentioned above. As a result, the goal mentioned above is achieved.

[0030] Optionally, the piston is arranged to alternate in at least one cylinder between a lower dead center and an upper dead center, where the control arrangement is configured to:

- open at least one valve on at least one cylinder, when the piston is in an upper dead center region.

[0031] In this way, the pressure in the cylinder, and therefore also the compression in the cylinder, can be estimated more precisely, since the pressure in the cylinder is higher when the piston is in a region of the upper dead center, the that when the piston is in a region of the bottom dead center.

[0032] Optionally, the valve control arrangement comprises a valve actuator, and where the fluid chamber is arranged between the valve actuator and at least one valve. In this way, the pressure estimation in at least one cylinder can be done in an efficient and reliable way, because the fluid pressure measured in the fluid chamber provides a clear and reliable indication of the pressure in at least one cylinder.

[0033] Optionally, the internal combustion engine comprises a compression release brake arrangement comprising the valve control arrangement. Thus, according to these modalities, the internal combustion engine control arrangement can selectively open at least one valve in at least one cylinder, measure the fluid pressure in the fluid chamber and estimate the pressure in at least one cylinder at the pressure of fluid measured in the fluid chamber, during compression release braking. In this way, the pressure in at least one cylinder can be estimated even more efficiently and reliably. This is because there is no combustion during the compression release braking. As an additional result, the compression of at least one cylinder can be estimated even more efficiently and reliably, since

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13/29 that the pressure in at least one cylinder, during compression release braking, provides a clear indication of the compression of at least one cylinder. In addition, a vehicle's internal combustion engine in normal traffic will perform compression release braking frequently. Therefore, pressure estimation on at least one cylinder can be performed frequently, which provides additional conditions for detecting component wear at an early stage, further reducing the risk of excessive component wear and therefore potentially further reducing plus the cost of maintenance and repair of the internal combustion engine.

[0034] Optionally, the internal combustion engine comprises at least two cylinders and a crank angle sensor, where the control arrangement is configured to:

- monitor a series of consecutive pressure rise events for the measured fluid pressure, and

- identify a correlation between one or more consecutive pressure increase events and one of at least two cylinders, comparing the consecutive pressure increase events and the crank angle of the crankshaft. [0035] In this way, an internal combustion engine is provided capable of identifying the correlation between the estimated pressures and the cylinders, which gives the possibility to identify a cylinder having a deviating cylinder pressure. In addition, conditions are provided to estimate the pressure in two or more cylinders of an internal combustion engine using only one sensor. In this way, an internal combustion engine is provided capable of estimating the pressure in two or more cylinders, in an efficient, reliable and economical way.

[0036] According to a sixth aspect of the invention, the objective is achieved by a vehicle comprising wheels and an internal combustion engine according to some modalities, where the internal combustion engine is configured to supply motive energy to the vehicle through a or more vehicle wheels.

[0037] Since the vehicle comprises an internal combustion engine overcoming, or at least alleviating, at least some of the problems and

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14/29 disadvantages mentioned above, a vehicle is provided to overcome, or at least alleviate, at least some of the problems and disadvantages mentioned above. As a result, the goal mentioned above is achieved.

[0038] Other features and advantages of the present invention will become apparent when studying the attached claims and the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS [0039] Various aspects of the invention, including its particular characteristics and advantages, will be easily understood from the exemplary modalities discussed in the following detailed description and in the attached drawings, in which:

[0040] Figure 1 schematically illustrates a cross-sectional view of an internal combustion engine, according to some modalities.

[0041] Figure 2 schematically illustrates a side view of the internal combustion engine illustrated in Figure 1.

[0042] Figure 3 illustrates a graph showing a series of consecutive pressure increase events of a fluid pressure measured in an internal combustion engine fluid chamber, illustrated in Figure 1 and Figure 2.

[0043] Figure 4 illustrates a vehicle comprising wheels and the internal combustion engine illustrated in Figure 1 and Figure 2.

[0044] Figure 5 illustrates a method of estimating pressure in at least one cylinder of an internal combustion engine.

[0045] Figure 6 illustrates a computer-readable medium.

DETAILED DESCRIPTION OF THE INVENTION [0046] Aspects of the present invention will now be described in more detail. Similar numbers refer to similar elements throughout the text. Well-known functions or constructs will not necessarily be described in detail for brevity and / or clarity.

[0047] Figure 1 schematically illustrates a cross-sectional view of an internal combustion engine 1, according to some modalities. Here, the engine

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15/29 internal combustion 1 is, in some cases, called “engine 1” for the sake of brevity and / or clarity. The engine 1 comprises at least one cylinder 3.1 and a piston 5 arranged in each cylinder 3.1. Piston 5 is connected to a crankshaft 7, using a connecting rod 6. Piston 5 moves back and forth on cylinder 3.1 by rotating crankshaft 7, between an upper dead center TDC and a BDC lower dead center. The engine 1 comprises an inlet system 8, which in the exemplary embodiments, is illustrated as an inlet duct. Inlet system 8 may comprise other components, such as an air filter, an accelerator, a fuel injector, an airflow sensor, etc.

[0048] The engine 1 further comprises at least one inlet valve 10 arranged in each cylinder 3.1, that at least one inlet valve 10 is connected to the inlet system 8. The inlet valve 10 is arranged to control the gas flow on the cylinder 3.1. The engine 1 further comprises an inlet valve control arrangement 12.1 configured to control each inlet valve 10 based on a rotation position of the crankshaft 7. The engine 1 further comprises at least one exhaust valve 9 arranged in each cylinder 3.1, that at least one exhaust valve 9 is connected to an exhaust outlet 14 of engine 1. The exhaust valve 9 is arranged to control the flow of gas out of cylinder 3.1. The engine 1 further comprises an exhaust valve control arrangement 12.2 configured to control each exhaust valve 9 based on the rotation position of the crankshaft 7. In Figure 1, at least one inlet valve 10 and at least one valve exhaust 9 are shown in a closed position. In the closed position, each valve 9, 10 abuts against a respective valve seat to close the fluid connection between the cylinder 3.1 and the respective inlet system 8 and the exhaust outlet 14.

[0049] The inlet valve control arrangement 12.1 is arranged to control at least one inlet valve 10 between the closed position and an open position by moving at least one inlet valve 10 in one direction towards the cylinder 3.1. A fluid connection is thus opened between the inlet system 8 and the cylinder 3.1. Likewise, the exhaust valve control arrangement

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12.2 is arranged to control at least one exhaust valve 9 between the closed position and an open position, displacing at least one exhaust valve 9 in one direction towards the cylinder 3.1. In this way, a fluid connection is opened between cylinder 3.1 and exhaust outlet 14. After a valve 9, 10 is moved from the closed to the open position, valve 9, 10 is lifted from its valve seat. According to the illustrated embodiments, at least one exhaust valve 9, as well as at least one inlet valve 10, comprises a trigger valve, which can also be called a mushroom valve.

[0050] Engine 1 further comprises a fuel injector 16 arranged to directly inject fuel into cylinder 3.1. Engine 1, in the illustrated modes, is a compression ignition engine. According to other modalities, the engine can be an Otto engine with a spark igniter, where the Otto engine can be designed to run on gas, gasoline, alcohol or similar volatile fuels or combinations thereof. Fuel can be directly injected into cylinder 3.1 using a fuel injector, or it can be added to the air that enters before entering cylinder 3.1, for example, through a fuel injector disposed in an engine inlet duct 1.

[0051] The exhaust valve control arrangement 12.2 and the inlet valve control arrangement 12.1 can each comprise one or more cam axes rotatably connected to the crankshaft 7, where the cam axes comprise 20.1 cam lobes , 20.2 arranged to move the valves 9, 10 to an open position by pressing the valve stems of the valves 9, 10 by rotating the cam shaft 7. The cam lobes 20.1, 20.2 can press directly on the valve stems of the valves 9 , 10, or can press the valve stems of the 9, 10 valves via arrangements such as pull rods, swing arms, hydraulic arrangements or the like. The exhaust valve control arrangement 12.2, and / or the inlet valve control arrangement 12.1, may according to other modalities comprise electric, pneumatic or hydraulic actuators arranged to control valves 9, 10 based on the rotation position of the crankshaft 7. The rotational position of the crankshaft 7 can be obtained

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17/29 using a crank angle sensor 22.

[0052] Engine 1 further comprises a valve control arrangement 11. The valve control arrangement 11 may be arranged in the exhaust valve control arrangement 12.2 and may use and / or share components thereof, as is the case with according to the illustrated modalities. The valve control arrangement 11 comprises a fluid component 18 comprising a fluid chamber 13. According to the illustrated embodiments, the fluid component 18 is a hydraulic component and the fluid chamber 13 is a hydraulic chamber. The valve control arrangement 11 comprises a valve actuator 19. According to the illustrated embodiments, the valve actuator 19 comprises a cam lobe disposed on a cam shaft 17. According to other embodiments, the valve actuator can comprise a swing arm that can be connected to a cam shaft, for example, via one or more pull rods, or the like. The fluid component 18 and the fluid chamber 13 are arranged between the valve actuator 19 and at least one valve 9. The valve actuator 19 is arranged to abut against a part 18.1 of the fluid component 18. The fluid component 18 is arranged to transfer movement from valve actuator 19 to valve 9 when fluid pressure is provided in fluid chamber 13. Fluid component 18 is arranged not to transfer movement from valve actuator 19 to valve 9 when it is not fluid pressure is provided in the fluid chamber 13. According to the illustrated modalities, the fluid pressure in the fluid chamber 13 is provided by closing a first control valve 24 so that the movement of the valve actuator 19 can accumulate a fluid pressure in the fluid chamber 13 to thereby transfer movement from valve actuator 19 to valve 9, as will be explained below.

[0053] The internal combustion engine 1 comprises a compression release brake arrangement 21. The compression release brake arrangement 21 is configured to selectively perform the compression release braking of the internal combustion engine 1. According to the illustrated modalities, the valve control arrangement 11 forms part of the brake release arrangement

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18/29 compression 21. Valve control arrangement 11 is configured to selectively open the exhaust valve 9 on at least one cylinder 3.1 near the end of the compression stroke of the engine 1. In this way, the energy stored in the compressed gases during the compression stroke will not be returned to the crankshaft 7 in the subsequent expansion stroke, which increases the engine's braking torque

1. The valve control arrangement 11 is configured to selectively open the exhaust valve 9 on at least one cylinder 3.1, providing a fluid pressure in the fluid chamber 13.

[0054] According to the illustrated modalities, the valve control arrangement 11 comprises the first control valve 24 and a second control valve 26. The second control valve 26 is connected to a pressurized fluid circuit 28 and the first control valve 24. In accordance with the illustrated modalities, fluid circuit 28 is an oil circuit. The oil circuit can be part of an engine oil circuit 1.

[0055] Motor 1 comprises a control arrangement 23 configured to control at least the second control valve 26. During a power production state of motor 1, control arrangement 23 controls the second control valve 26 to a state closed. When the second control valve 26 is in the closed state, no fluid pressure is applied to the first control valve 24. When no fluid pressure is applied to the first control valve 24, the first control valve 24 is in a state Open. When the first control valve 24 is in the open state, fluid, for example, oil, can flow into and out of the fluid chamber 13 through the first control valve 24 by rotating the cam shaft 17. Thus, the movement of the valve actuator 19 will not be transferred to the exhaust valve 9. As a result, the valve actuator 19 does not force the exhaust valve 9 to open when the second control valve 26 is in the closed state. However, according to the illustrated modalities, the lobe of the cam 20.2 of the exhaust valve control arrangement 12.2 forces the exhaust valve 9 to open when the second control valve 26 is in the closed state. This is because the cam lobe 20.2 of the

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19/29 exhaust valve control arrangement 12.2 is provided with a higher height than valve actuator 19 and will thus provide a longer stroke length than valve actuator 19, and because fluid component 18 is configured to transfer movement of the cam lobe 20.2 to the exhaust valve 9 when subjected to the stroke length of the cam lobe 20.2. As a result, motor 1 can operate in an energy producing state when the second control valve 26 is in the closed state.

[0056] To initiate the compression release brake, the compression release brake arrangement 21 controls the second control valve 26 to an open state. In the open state, the second control valve 26 applies a fluid pressure to the first control valve 24. When a fluid pressure is applied to the first control valve 24, the first control valve 24 assumes an active state. In the active state, the first control valve 24 allows the fluid to flow into the fluid chamber 13 and prevents the fluid from flowing out of the fluid chamber 13. As a result, the fluid chamber will be filled with fluid upon rotation of the cam shaft 17. When the fluid chamber 13 is filled with fluid and when the valve actuator 19 of the cam shaft 17 pushes to part 18.1 of the fluid component 18, the force of the valve actuator 19 is transferred to the exhaust valve 9, through fluid component 18, which forces exhaust valve 9 into the open position.

[0057] The internal combustion engine 1 comprises a sensor 15 configured to measure the fluid pressure in the fluid chamber 13. The exhaust valve 9 comprises a certain surface area facing the cylinder, and the fluid chamber 13 is provided with a certain cross-sectional area. Thus, the fluid pressure measured in the fluid chamber 13 provides a clear and reliable indication of the pressure in the cylinder 3.1 at the time of opening of the exhaust valve 9. The control arrangement 23 is connected to the sensor 15 and is configured to estimate the pressure on at least one cylinder 3.1 based on the fluid pressure measured in the fluid chamber 13. In addition to the fluid pressure measured in the fluid chamber 13, the pressure estimate on at least one 3.1 cylinder can be based on the surface area of the valve escape

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20/29 facing cylinder 3.1, the cross-sectional area of the fluid chamber 13, the rotation speed of the internal combustion engine 1, the friction losses, the pressure in the inlet system 8, the boost pressure of a loading, etc. [0058] Control arrangement 23 is configured to open at least one valve 9 on at least one cylinder 3.1, when piston 5 is in a region of the upper dead center, such as when the piston is within the range of 20 degrees of crank angle before neutral above 20 degrees crank angle after upper neutral. The pressure inside an engine cylinder is the highest when the piston is in the top dead center. When opening at least one valve 9 on at least one cylinder 3.1, when piston 5 is in the upper dead center region, the braking force of motor 1 is increased. In addition, pressure estimation in cylinder 3.1 can be performed reliably due to the high pressure. According to the illustrated modalities, the control arrangement 23 is configured to open at least one valve 9 in at least one cylinder, measuring the fluid pressure in the fluid chamber 13 and estimating the pressure in at least one cylinder 3.1 based on the fluid pressure measured in the fluid chamber 13 during engine braking. According to other modalities, the control arrangement 23 can, alternatively, or additionally, be configured to open at least one valve 9 in at least one cylinder 3.1, measuring the fluid pressure in the fluid chamber 13 and estimating the pressure in at least one cylinder 3.1 based on the fluid pressure measured in the fluid chamber 13 during motorization and / or starting engine 1.

[0059] According to some modalities, the control arrangement 23 can be configured to open at least one valve 9 in at least one cylinder 3.1, when piston 5 is at a distance from the bottom dead center, performing a phase shift of the exhaust valve control arrangement 12.2. In this way, the cam lobe 20.2 of the exhaust valve control arrangement 12.2 will force the exhaust valve 9 to open when piston 5 is at a distance from the lower dead center and the pressure in at least one cylinder 3.1 can be estimated with based on the fluid pressure measured in the fluid chamber 13. According to such

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21/29 embodiments, engine 1 may comprise a phase displacement device instead of, or in addition to, the compression release brake arrangement 21. [0060] Figure 2 schematically illustrates a side view of the internal combustion engine 1 illustrated in Figure 1. The internal combustion engine 1 comprises six cylinders 3.1 - 3.6 arranged in line. The engine illustrated in Figure 2 can thus be called an inline six-cylinder engine. The internal combustion engine 1 can comprise a number of cylinders other than six, which can be arranged in a configuration other than in line, as will be explained below. Cylinder 3.1 shown in Figure 1 is the first cylinder 3.1 of the six cylinders 3.1 - 3.6 shown in Figure 2. Each of the remaining cylinders 3.2 - 3.6 of the six cylinders 3.1 - 3.6 comprises a piston, at least one valve arranged on cylinder 3.2 - 3.6, where at least one valve is arranged to control the flow of gas into and / or out of the cylinder 3.2 - 3.6, and a valve control arrangement provided with a fluid component comprising a fluid chamber. The second control valve 24 of the compression release brake arrangement 21 is fluidly connected to each fluid chamber of each cylinder

3.1 - 3.6 through a fluid connection. The sensor 15 shown in Figure 1 is configured to measure fluid pressure p at the fluid connection. In this way, the fluid pressure in each fluid chamber can be detected using a sensor

15. In embodiments in which the engine comprises cylinders arranged in more than one line, such as in a V configuration engine, the engine may comprise a sensor 15 per line of cylinders. Therefore, a V-configuration motor can comprise two sensors 15.

[0061] Figure 3 illustrates a graph showing a series of consecutive pressure increase events p1 - p6 of the measured fluid pressure p in the fluid chambers 13 of the internal combustion engine 1 illustrated in Figure 1 and Figure 2. The axis vertical of the graph shows the fluid pressure p and the horizontal axis shows the rotation position a of the crankshaft 7 of the engine 1.

[0062] According to the illustrated modalities, the control layout 23 configured to monitor a series of consecutive

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22/29 pressure p1 - p6 of the measured fluid pressure p and identify a correlation between one or more consecutive pressure increase events p1 - p6 and one of at least two cylinders 3.1 - 3.6 comparing the consecutive pressure increase events p1 - p6 and the crankshaft angle a of the crankshaft 7. The comparison between consecutive pressure increase events p1 - p6 and the crankshaft angle a of the crankshaft 7 can include a comparison between the position of consecutive events pressure increase p1 - p6 and crank angle a of crankshaft 7. Thus, a cylinder with a deviating cylinder pressure can be identified in an efficient, reliable and economical way. In addition, conditions are provided to estimate the pressure in two or more cylinders of an internal combustion engine using only one sensor.

[0063] Furthermore, as shown in Figure 3, the control arrangement can compare each pressure increase event p1 - p6 and a first limit value t1 and a second limit value t2. In such embodiments, control arrangement 23 may determine that the pressure of a cylinder is too low if the peak of a pressure increase event p1 - p6 is below the first limit value t1. In Figure 3, the pressure increase event p5 is below the first limit value. According to the illustrated modalities, the pressure increase event p5 belongs to cylinder 3.5, which, as explained above, can be identified by comparing the consecutive pressure increase events p1 - p6 and the crank angle to that of the crank 7. Control arrangement 23 may determine that the pressure of a cylinder is too high if the peak of a pressure increase event p1 - p6 is above the second limit value t2. Too high cylinder pressure can be caused by a worn cam shaft that can cause one or more valves to open too late. Control arrangement 23 can issue an alert in a driver's environment of a vehicle that houses the internal combustion engine 1 if the estimated cylinder pressure is above the second limit value t2 and / or below the first limit value t1. The first and / or the second limit value t1, t2 can be determined based on the rotation speed of the internal combustion engine 1, friction losses, pressure in the inlet system 8, boost pressure of a

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23/29 charging device, etc.

[0064] According to other modalities, control arrangement 23 may determine that the pressure of a cylinder is too low or too high by comparing the pressure increase events p1 - p6 and identifying whether one or more of the pressure increase events p1 - p6 deviate significantly from the other pressure increase events p1 - p6. In this way, a cylinder with a very high or very low cylinder pressure can be detected in a simple, effective and reliable way.

[0065] Furthermore, according to some modalities, control arrangement 23 can be configured to compare the phase and / or duration of the monitored pressure increase events p1 - p6 with stored and / or predetermined values for pressure increase events pressure and / or phase. In this way, a control arrangement 23 can be provided with an improved ability to detect whether the components of the engine 1 have been subjected to wear which affects the compression in the cylinders of the engine 1.

[0066] Figure 4 illustrates a vehicle 25 comprising wheels 27 and the internal combustion engine 1 illustrated in Figure 1 and Figure 2. The internal combustion engine 1 is configured to provide driving force to vehicle 25 through one or more wheels 27 of vehicle 25.

[0067] Vehicle 25 illustrated in Figure 4 is a truck. However, the internal combustion engine 1 can be included in another type of manned or unmanned vehicle for land or water propulsion, such as a truck, a bus, a construction vehicle, a tractor, a car, a boat, a ship or similar. In addition, the internal combustion engine 1, as referred to herein, can be a stationary internal combustion engine, for example, an internal combustion engine of a motor driven generator.

[0068] Figure 5 illustrates a method 100 of estimating a pressure in at least one cylinder of an internal combustion engine. The internal combustion engine can be an internal combustion engine 1 according to the modalities illustrated in Figure 1 and Figure 2. In addition, some characteristics and advantages are

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24/29 explained with reference to Figure 3. Therefore, below, reference is made to Figure 1, Figure 2, as well as Figure 3. Method 100 is a method for estimating pressure in at least one cylinder 3.1 - 3.6 of an internal combustion engine 1, where the internal combustion engine 1 comprises:

- at least one cylinder 3.1 - 3.6,

- a piston 5 arranged in each cylinder 3.1 - 3.6,

- a crankshaft 7,

- at least one valve 9 arranged in each cylinder 3.1 - 3.6, where at least one valve 9 is arranged to control the flow of gas into and / or out of cylinder 3.1 - 3.6,

- a valve control arrangement 11 comprising a fluid chamber 13, and

- a sensor 15 configured to measure fluid pressure p in fluid chamber 13, where method 100 comprises the steps of:

- selectively open 110 at least one valve 9 in at least one cylinder 3.1 - 3.6, providing a fluid pressure p in the fluid chamber 13,

- measure 120 the pressure of fluid p in fluid chamber 13, and

- estimate 130 the pressure in at least one cylinder 3.1 - 3.6 based on the measured fluid pressure p in the fluid chamber 13.

[0069] According to some modalities, piston 5 is arranged to alternate in at least one cylinder 3.1 - 3.6 between a lower dead center and an upper dead center, where method 100 comprises the step of:

- open at least one valve 9 on at least one cylinder 3.1 - 3.6, when piston 5 is in an upper dead center region.

[0070] According to some embodiments, the valve control arrangement 11 comprises a valve actuator 19 and where the fluid chamber 13 is disposed between the valve actuator 19 and at least one valve 9.

[0071] According to some modalities, method 100 is performed during the braking of the internal combustion engine 1, during the motorization of the internal combustion engine

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25/29 internal combustion 1, or when starting the internal combustion engine 1.

[0072] According to some modalities, the internal combustion engine 1 comprises a compression release brake arrangement 21 comprising valve control arrangement 11, where the compression release brake arrangement 21 is configured to selectively perform the compression release braking of the internal combustion engine 1 and where method 100 is performed during compression release braking.

[0073] According to some modalities, the internal combustion engine 1 comprises at least two cylinders 3.1 - 3.6 and a crank angle sensor 22, where method 100 comprises the steps of:

- monitor 140 a series of consecutive pressure increase events p1 - p6 of the measured fluid pressure p, and

- identify 150 a correlation between one or more consecutive pressure increase events p1 - p6 and one of at least two cylinders 3.1 - 3.6 comparing the consecutive pressure increase events p1 - p6 and the crank angle to that of the crankshaft 7 .

[0074] It will be appreciated that the various modalities described for method 100 are all combinable with control arrangement 23 as described herein. That is, the control arrangement 23 can be configured to perform any of the steps of method 110, 120, 130, 140, 150 and 111 of method 100. In addition, method 100, as described herein, can be performed during engine braking, during motorization and / or when starting the internal combustion engine 1.

[0075] Figure 6 illustrates a computer-readable medium 200 comprising instructions that, when executed by a computer, cause the computer to execute method 100 according to some modalities.

[0076] According to some modalities, the computer-readable medium 200 comprises a computer program comprising instructions which, when the program is executed by a computer, cause the computer to execute method 100 according to some modalities.

[0077] One skilled in the art will appreciate that the method of estimating a pressure

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26/29 on at least one cylinder of an internal combustion engine can be implemented by programmed instructions. These programmed instructions are typically comprised of a computer program that, when executed in control layout 23, ensures that control layout 23 performs the desired control, as do method steps 110, 120, 130, 140, 150, and 111 described herein. The computer program is normally part of a computer program product 200, which comprises a suitable digital storage medium, in which the computer program is stored.

[0078] Control arrangement 23 may comprise a calculation unit that can take the form of substantially any suitable type of processor or microcomputer circuit, for example, a circuit for digital signal processing (digital signal processor, DSP), a Central Processing Unit (CPU), a processing unit, a processing circuit, a processor, an Application Specific Integrated Circuit (ASIC), a microprocessor or other processing logic that can interpret and execute instructions. The term used here "calculation unit" can represent a processing circuit comprising a plurality of processing circuits, such as, for example, any, some or all of those mentioned above.

[0079] Control arrangement 23 may further comprise a memory unit, where the calculation unit may be connected to the memory unit, which may provide the calculation unit, for example, with stored program code and / or stored data that the calculation unit may need to make calculations. The calculation unit can also be adapted to store partial or final calculation results in the memory unit. The memory unit may comprise a physical device used to store data or programs, that is, sequences of instructions, on a temporary or permanent basis. According to some embodiments, the memory unit may comprise integrated circuits comprising silicon-based transistors. The memory unit can comprise, for example, a memory card, a flash memory, a memory

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27/29

USB, a hard drive or other similar volatile or non-volatile storage unit for storing data, such as, for example, ROM (read-only memory), PROM (programmable read-only memory), EPROM (erasable PROM), EEPROM ( Electrically erasable PROM), etc. in different modalities.

[0080] Control arrangement 23 is connected to the components of the internal combustion engine 1 to receive and / or send input and output signals. These input and output signals can comprise waveforms, pulses or other attributes that the input signal receiving devices can detect as information and which can be converted into processable signals by the control arrangement 23. These signals can then be supplied to the calculation unit. One or more output signal sending devices can be arranged to convert the calculation results of the calculation unit into output signals for transport to other parts of the vehicle control system and / or the component or components for which the signals are destined. Each of the connections to the respective components of the internal combustion engine 1 to receive and send input and output signals can take the form of one or more of a cable, a data bus, for example, a CAN bus (network area network). control), a MOST bus (media-driven systems transport) or some other bus configuration, or a wireless connection.

[0081] In the illustrated modalities, the internal combustion engine 1 comprises a control arrangement 23, but may alternatively be implemented totally or partially in two or more control arrangements or two or more control units.

[0082] Control systems in modern vehicles generally comprise a communication bus system consisting of one or more communication buses to connect a number of electronic control units (ECUs), or controllers, to various components on board the vehicle. . Such a control system can comprise a large number of control units and taking care of a specific function can be shared between two or more of them. Vehicles of the type in question here are therefore often supplied with significantly

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28/29 more control arrangements than shown in Figure 1, as one skilled in the art will certainly appreciate.

[0083] Computer program product 200 may be provided, for example, in the form of a data carrier carrying computer program code to perform at least some of the method steps 110, 120, 130, 140, 150 and 111 according to some modalities when loaded in one or more calculation units of the control layout 23. The data carrier can be, for example, a CD-ROM disk, as illustrated in Figure 6, or a ROM (read-only memory) , a PROM (programmable read-only memory), an EPROM (erasable PROM), a flash memory, an EEPROM (electrically erasable PROM), a hard drive, a memory card, an optical storage device, a magnetic storage device or any other appropriate medium, such as a disk or tape that may contain machine-readable data in a non-transitory manner. The computer program product can, in addition, be provided as computer program code on a server and can be transferred to the control layout 23 remotely, for example, via an Internet or intranet connection, or via other wired or wireless communication systems.

[0084] It is understood that the above is illustrative of several exemplary modalities and that the invention is defined only by the appended claims. One skilled in the art will appreciate that the exemplary modalities can be modified, and that different characteristics of the exemplary modalities can be combined to create different modalities from those described herein, without departing from the scope of the present invention, as defined by the appended claims. As explained above, the fluid chamber and the fluid component may, according to some embodiments, comprise a hydraulic chamber and a hydraulic component. Thus, throughout this description, the word "fluid" can be replaced by the word "hydraulic", or the word "liquid". For example, the hydraulic chamber and a hydraulic component can be part of a cylinder deactivation arrangement using hydraulic fluid, or a lost motion arrangement using

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29/29 hydraulic fluid.

[0085] Each of the cylinders 3.1 - 3.6 forms a combustion chamber. Thus, throughout this description, the word "cylinder" can be replaced by the word "combustion chamber".

[0086] As used here, the term "comprising" or "comprises" is open and includes one or more declared characteristics, elements, steps, components or functions, but does not prevent the presence or addition of one or more other characteristics, elements, steps, components, functions or groups thereof.

Claims (15)

1. Method (100) for estimating pressure in at least one cylinder (3.1 - 3.6) of an internal combustion engine (1), where the internal combustion engine (1) comprises: - at least one cylinder (3.1 - 3.6), - a piston (5) arranged in each cylinder (3.1 - 3.6); - a crankshaft (7), - at least one valve (9) arranged in each cylinder (3.1 - 3.6), where at least one valve (9) is arranged to control the flow of gas into and / or out of the cylinder (3.1 - 3.6), - a valve control arrangement (11) comprising a fluid chamber (13), and - a sensor (15) configured to measure the fluid pressure (p) in the fluid chamber (13), the method (100) characterized by the fact that it comprises the steps of: - selectively open (110) to at least one valve (9) within at least one cylinder (3.1 - 3.6), providing fluid pressure (p) in the fluid chamber (13), - measure (120) the fluid pressure (p) in the fluid chamber (13), and - estimate (130) the pressure in at least one cylinder (3.1 - 3.6) based on the measured fluid pressure (p) in the fluid chamber (13). 2. Method (100), according to claim 1, characterized by the fact that the piston (5) is arranged to alternate in at least one cylinder (3.1 - 3.6) between a lower dead center and an upper dead center, in that the method comprises the step of: - open (111) at least one valve (9) inside at least one cylinder (3.1 - 3.6), when the piston (5) is in a region of the upper dead center. Method (100) according to claim 1 or 2, characterized by the fact that the valve control arrangement (11) comprises a valve actuator (19), and where the fluid chamber (13) is arranged between the valve actuator (19) Petition 870180072837, of 8/20/2018, p. 38/46 2/5 and at least one valve (9). Method (100) according to any one of claims 1 to 3, characterized by the fact that method (100) is carried out during engine braking of the internal combustion engine (1), during motorization of the combustion engine internal combustion (1), or when starting the internal combustion engine (1). Method (100) according to any one of claims 1 to 4, characterized in that the internal combustion engine (1) comprises a compression release brake arrangement (21) comprising the valve control arrangement (11), where the compression release brake arrangement (21) is configured to selectively perform the compression release braking of the internal combustion engine (1), and where method (100) is performed during the release braking of compression. Method (100) according to any one of claims 1 to 5, characterized in that the internal combustion engine (1) comprises at least two cylinders (3.1 - 3.6) and a crank angle sensor (22 ), where method (100) comprises the steps of: - monitor (140) a series of consecutive pressure increase events (p1 - p6) of the measured fluid pressure (p), and - identify (150) a correlation between one or more consecutive pressure increase events (p1 - p6) and one of at least two cylinders (3.1 - 3.6) comparing the consecutive pressure increase events (p1 - p6) and the angle crankshaft (a) of the crankshaft (7). 7. Computer program characterized by the fact that it comprises instructions that, when the program is executed by a computer, cause the computer to execute the method (100) of the type defined in any one of claims 1 to 6. 8. Computer-readable medium (200), characterized by the fact that it comprises instructions that, when executed by a computer, cause the computer to execute the method (100) of the type defined in any one of claims 1 to 6. Petition 870180072837, of 8/20/2018, p. 39/46 3/5 9. Control arrangement (23) configured to estimate a pressure in at least one cylinder (3.1 - 3.6) of an internal combustion engine (1), where the internal combustion engine (1) comprises: - at least one cylinder (3.1 - 3.6), - a piston (5) arranged in each cylinder (3.1 - 3.6); - a crankshaft (7), - at least one valve (9) arranged on each cylinder (3.1 - 3.6), where at least one valve (9) is arranged to control the flow of gas into and / or out of the cylinder (3.1 - 3.6), - a valve control arrangement (11) comprising a fluid chamber (13), and - a sensor (15) configured to measure the fluid pressure (p) in the fluid chamber (13), the control arrangement (23) characterized by the fact that it is configured for: - selectively open at least one valve (9) in at least one cylinder (3.1 - 3.6), providing a fluid pressure (p) in the fluid chamber (13), - measure the fluid pressure (p) in the fluid chamber (13), and - estimate the pressure in at least one cylinder (3.1 - 3.6) based on the measured fluid pressure (p) in the fluid chamber (13). 10. Internal combustion engine (1), characterized by the fact that it comprises: - at least one cylinder (3.1 - 3.6), - a piston (5) arranged in each cylinder (3.1 - 3.6); - a crankshaft (7), - at least one valve (9) arranged in each cylinder (3.1 - 3.6), where at least one valve (9) is arranged to control the flow of gas into and / or out of the cylinder (3.1 - 3.6), - a valve control arrangement (11) comprising a fluid chamber (13), Petition 870180072837, of 8/20/2018, p. 40/46 4/5 - a sensor (15) configured to measure the fluid pressure (p) in the fluid chamber (13), and - a control arrangement (23) configured to: - selectively open at least one valve (9) in at least one cylinder (3.1 - 3.6), providing a fluid pressure (p) in the fluid chamber (13), - measure the fluid pressure (p) in the fluid chamber (13), and - estimate the pressure in at least one cylinder (3.1 - 3.6) based on the measured fluid pressure (p) in the fluid chamber (13). 11. Internal combustion engine (1), according to claim 10, characterized by the fact that the piston (5) is arranged to alternate in at least one cylinder (3.1 - 3.6) between a lower neutral and a neutral upper, where the control layout (23) is configured to: - open at least one valve (9) on at least one cylinder (3.1 - 3.6), when the piston (5) is in an upper dead center region. 12. Internal combustion engine (1) according to claim 10 or 11, characterized by the fact that the valve control arrangement (11) comprises a valve actuator (19), and where the fluid chamber (13 ) is arranged between the valve actuator (19) and at least one valve (9). 13. Internal combustion engine (1) according to any one of claims 10 to 12, characterized in that the internal combustion engine (1) comprises a compression release brake arrangement (21) comprising the valve control (11). 14. Internal combustion engine (1) according to any one of claims 10 to 13, characterized in that the internal combustion engine (1) comprises at least two cylinders (3.1 - 3.6) and an angle sensor. crank (22), where the control arrangement (23) is configured to: - monitor a series of consecutive pressure increase events (p1 - p6) of the measured fluid pressure (p), and - identify a correlation between one or more consecutive pressure increase events (p1 - p6) and one of at least two cylinders (3.1 - 3.6) Petition 870180072837, of 8/20/2018, p. 41/46 5/5 comparing the consecutive pressure increase events (p1 - p6) and the crank angle (a) of the crankshaft (7). 15. Vehicle (25) characterized by comprising wheels (27) and an internal combustion engine (1), of the type defined in any one of claims 10 to 14, wherein the internal combustion engine (1) is configured to provide power drive the vehicle (25) through one or more of the wheels (27) of the vehicle (25).