DE102018006654B4 - Method for estimating pressure in a cylinder of an internal combustion engine, internal combustion engine and associated devices - Google Patents

Abstract

A method (100) for estimating a pressure in at least one cylinder (3.1 - 3.6) of an internal combustion engine (1), the internal combustion engine (1) comprising: - the at least one cylinder (3.1 - 3.6), - a piston (5) which is arranged in each cylinder (3.1 - 3.6), - a crankshaft (7), - at least one valve (9) which is arranged in each cylinder (3.1 - 3.6), the at least one valve (9) being provided for this purpose, to control gas flow into and/or out of the cylinder (3.1 - 3.6), - a valve control arrangement (11) which comprises a fluid chamber (13) and - a sensor (15) which is designed to detect the fluid pressure (p) in of the fluid chamber (13), the method (100) comprising the steps of:- selectively opening (110) the at least one valve (9) in the at least one cylinder (3.1 - 3.6) by creating a fluid pressure (p) in the fluid chamber (13), - measuring (120) the fluid pressure (p) in the fluid chamber (13) and - estimating (130) the pressure in the at least one cylinder nder (3.1 - 3.6) based on the measured fluid pressure (p) in the fluid chamber (13).

Description

technical field

The present disclosure relates to a method for estimating pressure in at least one cylinder of an internal combustion engine. The present disclosure further relates to a computer program and a computer program product for performing the method, a control arrangement designed to estimate a pressure in at least one cylinder of an internal combustion engine, an internal combustion engine and a vehicle.

background

Internal combustion engines, such as four-stroke internal combustion engines, include one or more cylinders and a piston located in each cylinder. The pistons are connected to a crankshaft of the engine and are arranged to reciprocate within the cylinders upon rotation of the crankshaft. The engine typically includes one or more intake valves and one or more exhaust valves, and one or more fuel supply assemblies. The one or more intake valves and exhaust valves are controlled by a respective valve control assembly, which typically includes one or more camshafts rotatably connected to a crankshaft of the engine via a belt, chain, gears, push rods or the like. A four-stroke internal combustion engine performs four separate strokes when turning a crankshaft. A stroke is the full travel of the piston along the cylinder in either direction. The top position of the piston in the cylinder is commonly referred to as top dead center TDC and the bottom position of the piston in the cylinder as bottom dead center BDC.

The strokes are executed in the following order: intake stroke, compression stroke, expansion stroke and exhaust stroke. In the operation of a conventional four-stroke internal combustion engine, the intake valve control assembly controls the intake valves of a cylinder to an open condition during the intake stroke of a piston in the cylinder to allow air or an air and fuel mixture into the cylinder. During the compression stroke, all valves should be closed to allow the air or air and fuel mixture in the cylinder to be compressed. When the engine is in an energy-producing state, the fuel in the cylinder is ignited, usually towards the end of the compression stroke, for example by a spark plug or by heat of compression in the cylinder. Combustion of fuel in the cylinder significantly increases the pressure and temperature in the cylinder. The combustion of the fuel usually continues in a substantial part of the subsequent expansion stroke. The increased pressure and temperature in the cylinder caused by the combustion are partially converted into mechanical work, which is supplied to the crankshaft during the expansion stroke. Of course, all valves should remain closed during the expansion stroke so that the increased pressure and temperature can be converted into mechanical work. The expansion stroke is usually also referred to as the combustion stroke, since the majority of the combustion usually takes place during the expansion stroke. In the subsequent exhaust stroke, the exhaust valve control arrangement controls the exhaust valves of the cylinder to an open state so that exhaust gases can be expelled from the cylinder into an exhaust system.

When the engine is allowed to run, such as when the driver of a vehicle releases an accelerator pedal, the engine continues to operate at the strokes described above, except that the engine is not normally supplied with fuel and thus no combustion at the end of the compression stroke or during it of the expansion stroke takes place. In this state, the engine provides some braking torque due to internal friction and by pumping air from the intake to the exhaust on the intake and exhaust strokes respectively. When a piston moves up during the compression stroke, the gases trapped in the cylinder are compressed. The compressed gases oppose the upward movement of the piston. However, the energy stored in the compressed gases is almost completely returned to the crankshaft during the subsequent expansion stroke. In this case, the compression stroke together with the subsequent expansion stroke does not contribute to a significant braking torque of the engine during normal running of the engine.

A compression brake assembly is an engine braking mechanism used in some engines. When activated, it opens the exhaust valves in the cylinders after the compression stroke and releases the compressed air trapped in the cylinders to the exhaust system. The energy stored in the compressed gases during the compression stroke is not returned to the crankshaft during the subsequent expansion stroke, which increases the engine's braking torque.

In some arrangements, the exhaust valves can be deactivated so that they remain closed during the exhaust stroke. Usually For example, this is achieved by a so-called idle arrangement which is designed not to transfer movement caused by exhaust cam lobe to the exhaust valve when actuated. This means that the air in the cylinders is also compressed during the exhaust stroke. By using a valve control arrangement that opens the exhaust valves near the end of the exhaust stroke, the compressed air trapped in the cylinders is released to the exhaust system. This arrangement almost doubles the braking torque since compression and decompression processes are performed on both the compression stroke and the exhaust stroke.

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, such as a gasoline engine, it is a spark plug that ignites the fuel. The compression in the cylinders is an important factor in the operation and efficiency of the engine. The pressure in the cylinders that occurs during compression indicates the compression in the cylinders. Compression in an engine's cylinders can deteriorate over time as engine components wear out, such as the cylinders, piston, piston rings, valves, valve seats, etc. Also, on an engine with more than one cylinder, which most Vehicle engines have one or more cylinders wearing out in an unpredictable manner. In such a situation, the vehicle can be driven many kilometers before the worn cylinder is noticed, for example during a maintenance operation. However, it can happen that the worn cylinder goes unnoticed even during a maintenance operation, which can lead to further damage to the engine.

The pressure in the cylinders of an engine and thus also the compression of the cylinders can be measured with a pressure gauge arranged in each cylinder. However, this is an expensive solution to get the pressure in the cylinders, especially on a multi-cylinder engine. In addition, due to the hostile environment within an internal combustion engine cylinder, i.e. the significant amount of heat, pressure and vibration within the cylinder, such pressure gauges can be damaged during the life of the engine, leading to further costs for their replacement.

The use of pressure gauges placed in each cylinder is therefore an expensive and vulnerable solution to obtain the pressure in the cylinders. The most common way to determine the pressure in the cylinders is therefore a manual pressure measurement in a workshop with a manometer. Such a method is complex and expensive and must be carried out individually on each cylinder. In addition, such a method lacks the possibility of taking an instantaneous measurement of the pressure in the cylinders, e.g. while the engine is running. Also, in most cases, such a procedure is not part of a maintenance schedule and is therefore not performed if the engine otherwise appears to be running properly. Furthermore, many vehicles drive many kilometers between maintenance intervals. Accordingly, the compression of one or more cylinders may deteriorate significantly before this is detected.

According to the state of the art DE 10 2010 015 753 A1 Diagnostic systems and methods are known for variable lift mechanisms of an engine system having a camshaft driven fuel pump. The diagnosis uses the difference in fluid pressures determined when the fuel pump is deactivated.

Further revealed DE 103 15 070 A1 an engine valve actuation system and method GB 2 445 761 A an internal combustion engine with a pressure measurement system in a cylinder EP 3 184 762 A1 a method for checking the function of an air brake system and disclosed DE 10 2015 205 297 A1 an internal combustion engine with controlled valve opening times.

abstract

It is an object of the present invention to overcome or at least mitigate at least some of the problems and disadvantages noted above.

• - den mindestens einen Zylinder,
• - einen in jedem Zylinder angeordneten Kolben,
• - eine Kurbelwelle,
• - mindestens ein Ventil, das in jedem Zylinder angeordnet ist, wobei das mindestens eine Ventil dafür vorgesehen ist, die Gasströmung in den und/oder aus dem Zylinder zu steuern,
• - eine Ventilsteueranordnung mit einer Fluidkammer und
• - einen Sensor, der dazu ausgelegt ist, den Fluiddruck in der Fluidkammer zu messen,

wobei das Verfahren die Schritte umfasst von:

• - selektivem Öffnen des mindestens einen Ventils in den mindestens einen Zylinder, indem ein Fluiddruck in der Fluidkammer geschaffen wird,
• - Messen des Fluiddrucks in der Fluidkammer und
• - Schätzen des Drucks in dem mindestens einen Zylinder basierend auf dem gemessenen Fluiddruck in der Fluidkammer.

According to a first aspect of the invention, the object is achieved by a method for estimating a pressure in at least one cylinder of an internal combustion engine, the internal combustion engine comprising:

• - the at least one cylinder,
• - a piston located in each cylinder,
• - a crankshaft,
• - at least one valve arranged in each cylinder, the at least one valve being intended to control the gas flow into and/or out of the cylinder,
• - A valve control arrangement with a fluid chamber and
• - a sensor designed to measure the fluid pressure in the fluid chamber,

the method comprising the steps of:

• - selectively opening the at least one valve in the at least one cylinder by creating a fluid pressure in the fluid chamber,
• - measuring the fluid pressure in the fluid chamber and
• - estimating the pressure in the at least one cylinder based on the measured fluid pressure in the fluid chamber.

Because the method includes the step of estimating the pressure in the at least one cylinder based on the measured fluid pressure in the fluid chamber, a method is provided that estimates the pressure in the at least one cylinder in an efficient, reliable, and cost-effective manner. Furthermore, a method is provided that is able to estimate the compression of at least one cylinder in an efficient, reliable and cost-effective manner since the pressure in the cylinder is indicative of the compression in the cylinder. Furthermore, conditions are provided to obtain an instantaneous estimate of the pressure in the at least one cylinder and a compression of the at least one cylinder, e.g., when running the internal combustion engine, in an efficient, reliable, and cost-effective manner. Since an instantaneous estimation of compression in the at least one cylinder can be achieved efficiently, reliably and inexpensively, conditions are also provided to detect whether one or more components of the engine associated with the compression of the at least one cylinder, such as pistons, Piston rings of the piston, the at least one valve, valve seats of the at least one valve, the valve clearance of the at least one valve, etc. were subjected to wear that reduces compression. As a result, such wear on components can be detected at an early stage, which reduces the risk of excessive wear on the components and other components of the internal combustion engine and thus also potentially reduces the costs for maintenance and repair of the internal combustion engine. Since the wear of components can be detected at an early stage, the method also provides conditions for carrying out condition-based maintenance of an internal combustion engine.

Accordingly, a method is provided that overcomes or at least mitigates at least some of the problems and disadvantages noted above. This achieves the above objective.

• - Öffnens des mindestens einen Ventils in den mindestens einen Zylinder, wenn sich der Kolben in einem Bereich des oberen Totpunktes befindet.

Optionally, the piston is arranged to reciprocate in the at least one cylinder between a bottom dead center and a top dead center, the method comprising the step of:

• - Opening the at least one valve in the at least one cylinder when the piston is in a region of top dead center.

As a result, the pressure in the cylinder and thus also the compression in the cylinder can be estimated more accurately, since the pressure in the cylinder is higher when the piston is in a region of top dead center than when the piston is in a region of bottom dead center dead center is located.

Optionally, the valve control assembly includes a valve actuator, wherein the fluid chamber is located between the valve actuator and the at least one valve.

As a result, the pressure estimation in the at least one cylinder can be performed efficiently and reliably since the measured fluid pressure in the fluid chamber provides a clear and reliable indication of the pressure in the at least one cylinder.

Optionally, the method is performed during engine braking of the internal combustion engine, while running the internal combustion engine, or when starting the internal combustion engine. Consequently, a method is provided that estimates the pressure in the at least one cylinder even more efficiently and reliably. This is because there is no combustion when the engine is braked, started or left running. As a further result, the compression of the at least one cylinder can be estimated even more efficiently and reliably, since the pressure in the at least one cylinder gives a clear indication of the compression of the at least one cylinder when the engine is braked, when the engine is running and when the engine is started. Further, an engine of a vehicle frequently performs engine braking, engine running, and cranking. Therefore, the method can be performed frequently, which creates further conditions for the early detection of component wear, thereby further reducing the risk of excessive component wear and thus possibly further reducing the costs for maintenance and repair of the internal combustion engine.

Optionally, the internal combustion engine includes a compression release brake assembly that includes the valve control assembly, wherein the compression release brake assembly is configured to selectively perform compression release braking of the combustion engine, and wherein the method performed during decompression braking. Consequently, a method is provided that estimates the pressure in the at least one cylinder even more efficiently and reliably. This is because there is no combustion during decompression braking. As a further consequence of this, the compression of the at least one cylinder can be estimated even more efficiently and reliably since the pressure in the at least one cylinder during compression braking provides a clear indication of the compression of the at least one cylinder. Furthermore, in normal traffic, an internal combustion engine of a vehicle often performs decompression braking. Therefore, the method can be performed frequently, which provides further conditions for the early detection of component wear, thereby further reducing the risk of excessive component wear and thus potentially further reducing the cost of servicing and repairing the internal combustion engine.

• - Überwachen einer Reihe von aufeinanderfolgenden Druckerhöhungsereignissen des gemessenen Fluiddrucks und
• - Identifizieren einer Korrelation zwischen einem oder mehreren aufeinanderfolgenden Druckerhöhungsereignissen und einem der mindestens zwei Zylinder durch Vergleichen der aufeinanderfolgenden Druckerhöhungsereignisse mit dem Kurbelwinkel der Kurbelwelle.

Optionally, the internal combustion engine includes at least two cylinders and a crank angle sensor, the method including the steps of:

• - monitoring a series of successive pressurization events of the measured fluid pressure and
• - identifying a correlation between one or more consecutive pressure increase events and one of the at least two cylinders by comparing the consecutive pressure increase events with the crank angle of the crankshaft.

Thereby a method is provided that is able to identify the correlation between the estimated pressures and the cylinders, which offers the possibility to identify a cylinder with a different cylinder pressure in an engine with more than one cylinder. Furthermore, conditions are provided to estimate the pressure in two or more cylinders of an engine with only one sensor. This provides a method for efficiently, reliably, and inexpensively estimating the pressure in two or more cylinders of an internal combustion engine.

According to a second aspect of the invention, the object is achieved by a computer program comprising instructions which, when the program is executed by a computer, cause the computer to perform the method according to the embodiments described herein. Since the computer program comprises instructions which, when the program is executed by a computer, cause the computer to carry out the method according to the embodiments described herein, a computer program is provided which provides conditions for overcoming or at least alleviating at least some of the disadvantages mentioned above.

According to a third aspect of the invention, the object is achieved by a computer-readable medium comprising instructions which, when executed by a computer, cause the computer to perform the method according to the embodiments described herein. Since the computer-readable medium comprises instructions which, when the program is executed by a computer, cause the computer to perform the method according to the embodiments described herein, a computer-readable medium is provided which contains conditions for overcoming or at least alleviating at least some of the disadvantages mentioned above provides.

• - den mindestens einen Zylinder,
• - einen in jedem Zylinder angeordneten Kolben,
• - eine Kurbelwelle,
• - mindestens ein Ventil, das in jedem Zylinder vorgesehen ist, wobei das mindestens eine Ventil dafür vorgesehen ist, die Gasströmung in den und/oder aus dem Zylinder zu steuern,
• - eine Ventilsteueranordnung mit einer Fluidkammer und
• - einen Sensor, der dazu ausgelegt ist, den Fluiddruck in der Fluidkammer zu messen,

wobei die Steueranordnung ausgelegt ist zum:

• - selektiven Öffnen des mindestens einen Ventils in den mindestens einen Zylinder, indem ein Fluiddruck in der Fluidkammer geschaffen wird,
• - Messen des Fluiddrucks in der Fluidkammer und
• - Schätzen des Drucks in dem mindestens einen Zylinder basierend auf dem gemessenen Fluiddruck in der Fluidkammer.

According to a fourth aspect of the invention, the object is achieved by a control arrangement that is designed to estimate a pressure in at least one cylinder of an internal combustion engine, the internal combustion engine comprising:

• - the at least one cylinder,
• - a piston located in each cylinder,
• - a crankshaft,
• - at least one valve provided in each cylinder, the at least one valve being intended to control the flow of gas into and/or out of the cylinder,
• - A valve control arrangement with a fluid chamber and
• - a sensor designed to measure the fluid pressure in the fluid chamber,

wherein the control arrangement is designed to:

• - selectively opening the at least one valve in the at least one cylinder by creating a fluid pressure in the fluid chamber,
• - measuring the fluid pressure in the fluid chamber and
• - estimating the pressure in the at least one cylinder based on the measured fluid pressure in the fluid chamber.

Because the control arrangement is configured to estimate the pressure in the at least one cylinder based on the measured fluid pressure in the fluid chamber, a control arrangement is provided that efficiently, reliably, and inexpensively estimates the pressure in the at least one cylinder. Furthermore, a control arrangement is provided which is able to reduce the compression at least at least one cylinder in an efficient, reliable and inexpensive way, since the pressure in the cylinder indicates the compression in the cylinder. Furthermore, a control arrangement is provided that enables an instantaneous estimation of the pressure in the at least one cylinder and the compression of the at least one cylinder, for example while the internal combustion engine is running, in an efficient, reliable and cost-effective manner. In addition, because an instantaneous estimate of compression in the at least one cylinder can be efficiently, reliably, and inexpensively achieved, conditions are provided to detect whether one or more components of the engine associated with the compression of the at least one cylinder, such as the pistons , piston rings of the piston, the at least one valve, valve seats of the at least one valve, the valve clearance of the at least one valve, etc. were subjected to wear that reduces compression. As a result, such wear on components can be detected at an early stage, which reduces the risk of excessive wear on the components and other components of the internal combustion engine and thus potentially also reduces the costs for maintenance and repair of the internal combustion engine. Since wear of components can be detected at an early stage, the control arrangement also provides conditions for performing condition-based maintenance of an internal combustion engine that includes the control arrangement.

Accordingly, a control scheme is provided that overcomes or at least mitigates at least some of the problems and disadvantages noted above. This solves the above problem.

• - mindestens einen Zylinder,
• - einen in jedem Zylinder angeordneten Kolben,
• - eine Kurbelwelle,
• - mindestens ein Ventil, das in jedem Zylinder angeordnet ist, wobei das mindestens eine Ventil dafür vorgesehen ist, die Gasströmung in den und/oder aus dem Zylinder zu steuern,
• - eine Ventilsteueranordnung, die eine Fluidkammer umfasst,
• - einen Sensor, der dazu ausgelegt ist, den Fluiddruck in der Fluidkammer zu messen, und
• - eine Steueranordnung, die ausgelegt ist zum:
• - selektiven Öffnen des mindestens einen Ventils in den mindestens einen Zylinder, indem ein Fluiddruck in der Fluidkammer geschaffen wird,
• - Messen des Fluiddrucks in der Fluidkammer und
• - Schätzen des Drucks in dem mindestens einen Zylinder basierend auf dem gemessenen Fluiddruck in der Fluidkammer.

According to a fifth aspect of the invention, the object is achieved by an internal combustion engine comprising:

• - at least one cylinder,
• - a piston located in each cylinder,
• - a crankshaft,
• - at least one valve arranged in each cylinder, the at least one valve being intended to control the gas flow into and/or out of the cylinder,
• - a valve control arrangement comprising a fluid chamber,
• - a sensor designed to measure the fluid pressure in the fluid chamber, and
• - a control arrangement designed to:
• - selectively opening the at least one valve in the at least one cylinder by creating a fluid pressure in the fluid chamber,
• - measuring the fluid pressure in the fluid chamber and
• - estimating the pressure in the at least one cylinder based on the measured fluid pressure in the fluid chamber.

Since the control arrangement of the internal combustion engine is configured to estimate the pressure in the at least one cylinder based on the measured fluid pressure in the fluid chamber, an internal combustion engine is provided which is capable of controlling the pressure in the at least one cylinder efficiently, reliably and cost-effectively appreciate. Furthermore, an internal combustion engine capable of estimating the compression ratio of at least one cylinder efficiently, reliably and inexpensively is provided since the pressure in the cylinder is indicative of the compression ratio in the cylinder. Furthermore, an internal combustion engine is provided that is able to obtain an instantaneous estimate of the pressure in the at least one cylinder and the compression of the at least one cylinder, for example during running of the internal combustion engine in an efficient, reliable and cost-effective manner. In addition, since an instantaneous estimation of compression in the at least one cylinder can be achieved efficiently, reliably, and inexpensively, conditions are provided to detect whether one or more components of the internal combustion engine associated with the compression of the at least one cylinder, such as the pistons , piston rings of the piston, the at least one valve, valve seats of the at least one valve, the valve clearance of the at least one valve, etc. have been subjected to wear that reduces compression. As a result, such wear on components can be detected at an early stage, which reduces the risk of excessive wear on the components and other components of the internal combustion engine and thus potentially also reduces the costs for maintenance and repair of the internal combustion engine. Since component wear can be detected at an early stage, conditions are also provided for condition-based maintenance of the internal combustion engine.

Accordingly, an internal combustion engine is provided that overcomes or at least mitigates at least some of the problems and disadvantages noted above. This solves the above problem.

• - Öffnen des mindestens einen Ventils in den mindestens einen Zylinder, wenn sich der Kolben in einem Bereich des oberen Totpunktes befindet.

Optionally, the piston is arranged in such a way that it moves between a bottom dead center and a top dead center in the at least one cylinder. and is moved up, the control arrangement being adapted to:

• - Opening the at least one valve in the at least one cylinder when the piston is in a region of top dead center.

As a result, the pressure in the cylinder and thus also the compression in the cylinder can be estimated more accurately, since the pressure in the cylinder is higher when the piston is in a region of top dead center than when the piston is in a region of bottom dead center dead center is located.

Optionally, the valve control assembly includes a valve actuator, wherein the fluid chamber is located between the valve actuator and the at least one valve. As a result, the pressure estimation in the at least one cylinder can be performed efficiently and reliably since the measured fluid pressure in the fluid chamber provides a clear and reliable indication of the pressure in the at least one cylinder.

Optionally, the internal combustion engine includes a compression release brake assembly that includes the valve control assembly. Thus, according to these embodiments, the internal combustion engine control arrangement can selectively open the at least one valve in the at least one cylinder, measure the fluid pressure in the fluid chamber, and estimate the pressure in the at least one cylinder based on the measured fluid pressure in the fluid chamber during compression release braking. As a result, the pressure in the at least one cylinder can be estimated even more efficiently and reliably. This is because there is no combustion during decompression braking. As a further result, the compression of the at least one cylinder can be estimated even more efficiently and reliably since the pressure in the at least one cylinder during decompression braking gives a clear indication of the compression of the at least one cylinder. Furthermore, in normal traffic, an internal combustion engine of a vehicle often performs decompression braking. Therefore, the estimation of the pressure in the at least one cylinder can be performed frequently, which provides further conditions for the early detection of component wear, thereby further reducing the risk of excessive component wear and thus potentially also the costs for maintenance and repair of the internal combustion engine be lowered further.

• - Überwachen einer Reihe von aufeinanderfolgenden Druckerhöhungsereignissen des gemessenen Fluiddrucks und
• - Identifizieren einer Korrelation zwischen einem oder mehreren aufeinanderfolgenden Druckerhöhungsereignissen und einem der mindestens zwei Zylinder durch Vergleichen der aufeinanderfolgenden Druckerhöhungsereignisse mit dem Kurbelwinkel der Kurbelwelle.

Optionally, the internal combustion engine includes at least two cylinders and a crank angle sensor, wherein the control arrangement is designed to:

• - monitoring a series of successive pressurization events of the measured fluid pressure and
• - identifying a correlation between one or more consecutive pressure increase events and one of the at least two cylinders by comparing the consecutive pressure increase events with the crank angle of the crankshaft.

This provides an internal combustion engine capable of identifying the correlation between the estimated pressures and the cylinders, providing the ability to identify a cylinder with a deviating cylinder pressure. Furthermore, conditions are provided to estimate the pressure in two or more cylinders of an internal combustion engine with only one sensor. This provides an internal combustion engine capable of estimating the pressure in two or more cylinders efficiently, reliably, and inexpensively.

According to a sixth aspect of the invention, the object is achieved by a vehicle comprising wheels and an internal combustion engine according to some embodiments, wherein the internal combustion engine is configured to provide motive power to the vehicle via one or more of the vehicle's wheels.

Because the vehicle includes an internal combustion engine that overcomes or at least mitigates at least some of the problems and disadvantages noted above, a vehicle is provided that overcomes or at least mitigates at least some of the problems and disadvantages noted above. This solves the above problem.

Other features and advantages of the present invention will become apparent upon study of the appended claims and the following detailed description.

character list

• 1 schematisch einen Querschnitt durch einen Verbrennungsmotor gemäß einigen Ausführungsformen,
• 2 schematisch eine Seitenansicht des in 1 dargestellten Verbrennungsmotors,
• 3 ein Diagramm, das eine Reihe von aufeinanderfolgenden Druckerhöhungsereignissen eines gemessenen Fluiddrucks in einer Fluidkammer des Verbrennungsmotors zeigt, wie in 1 und 2 dargestellt,
• 4 ein Fahrzeug mit Rädern und dem in 1 und 2 dargestellten Verbrennungsmotor,
• 5 ein Verfahren zum Schätzen eines Drucks in mindestens einem Zylinder eines Verbrennungsmotors und
• 6 ein computerlesbares Medium.

Various aspects of the invention, including its distinctive features and advantages, will be readily understood from the exemplary embodiments set forth in the following detailed description and the accompanying drawings. In these show:

• 1 schematically a cross section through an internal combustion engine according to some embodiments,
• 2 schematically a side view of the in 1 shown combustion engine,
• 3 a diagram showing a series of successive pressure increase events of a measured fluid pressure in a fluid chamber of the internal combustion engine, as in FIG 1 and 2 shown,
• 4 a vehicle with wheels and the in 1 and 2 shown combustion engine,
• 5 a method for estimating a pressure in at least one cylinder of an internal combustion engine and
• 6 a computer-readable medium.

Detailed description

Aspects of the present invention will now be described in more detail. Like numbers refer to like elements throughout the specification. Well-known functions or constructions are not necessarily described in detail for the sake of brevity and/or clarity.

1 schematically shows a cross section through an internal combustion engine 1 according to some embodiments. Herein, the internal combustion engine 1 is referred to as “the engine 1” in some cases for brevity and/or clarity. The engine 1 comprises at least one cylinder 3.1 and a piston 5 arranged in each cylinder 3.1. The piston 5 is connected to a crankshaft 7 via a connecting rod 6. The piston 5 moves forwards and backwards in the cylinder 3.1 upon rotation of the crankshaft 7, between a top dead center TDC and a bottom dead center BDC. The engine 1 includes an intake system 8, shown as an intake manifold in the exemplary embodiments shown. The intake system 8 may include other components such as an air cleaner, throttle body, fuel injector, air flow sensor, and so on.

The engine 1 also includes at least one intake valve 10 arranged in each cylinder 3.1, the at least one intake valve 10 being connected to the intake system 8. The inlet valve 10 is provided to control the gas flow into the cylinder 3.1. The engine 1 further comprises an intake valve control arrangement 12.1, which is designed to control each intake valve 10 on the basis of a rotational position of the crankshaft 7. The engine 1 further comprises at least one exhaust valve 9 arranged in each cylinder 3.1, the at least one exhaust valve 9 being connected to an exhaust outlet 14 of the engine 1. The exhaust valve 9 is provided to control the flow of gas out of the cylinder 3.1. The engine 1 further comprises an exhaust valve control arrangement 12.2, which is designed to control each exhaust valve 9 based on the rotational position of the crankshaft 7. In 1 the at least one inlet valve 10 and the at least one outlet valve 9 are each shown in a closed position. In the closed position, each valve 9, 10 rests against a corresponding valve seat to close the fluid connection between the cylinder 3.1 and the intake system 8 and the exhaust outlet 14, respectively.

The intake valve control arrangement 12.1 is intended to control the at least one intake valve 10 between the closed position and an open position by displacing the at least one intake valve 10 in a direction into the cylinder 3.1. This opens a fluid connection between the intake system 8 and the cylinder 3.1. Likewise, the exhaust valve control arrangement 12.2 is provided for controlling the at least one exhaust valve 9 between the closed position and an open position by the at least one exhaust valve 9 being displaced in a direction into the cylinder 3.1. As a result, a fluid connection between the cylinder 3.1 and the exhaust gas outlet 14 is opened. Upon displacement of a valve 9, 10 from the closed position to the open position, the valve 9, 10 is lifted from its valve seat. According to the illustrated embodiments, the at least one outlet valve 9 and the at least one inlet valve 10 include a poppet valve, which can also be referred to as a “mushroom valve”.

The engine 1 also includes a fuel injector 16 intended to inject fuel directly into the cylinder 3.1. The engine 1 in the illustrated embodiments is a compression ignition engine. According to further embodiments, the engine may be a spark-ignition spark-ignition engine, wherein the spark-ignition engine may be configured to run on gas, gasoline, alcohol, or similar volatile fuels, or combinations thereof. The fuel can be injected directly into the cylinder 3.1 by means of a fuel injector or it can be added to the incoming air before entering the cylinder 3.1, for example through a fuel injector arranged on an intake port of the engine 1.

The exhaust valve control arrangement 12.2 and the intake valve control arrangement 12.1 10 may each comprise one or more camshafts rotatably connected to the crankshaft 7, the camshafts comprising cam lobes 20.1, 20.2 arranged to open the valves 9, 10 by pressing on valve stems of the valves 9, 10 upon rotation of the camshaft 7 in relocate an open position. The cam lobes 20.1, 20.2 can press directly on the valve stems of the valves 9, 10 or press on the valve stems of the valves 9, 10 via other arrangements such as push rods, rocker arms, hydraulic arrangements or the like. According to further embodiments, the outlet valve control arrangement 12.2 and/or the inlet valve control arrangement 12.1 can comprise electric, pneumatic or hydraulic actuators which are provided for controlling the valves 9, 10 on the basis of the rotational position of the crankshaft 7. The rotational position of the crankshaft 7 can be obtained using a crank angle sensor 22 .

The engine 1 further comprises a valve control arrangement 11. The valve control arrangement 11 can be arranged on the exhaust valve control arrangement 12.2 and can use and/or share its components, as is the case according to the illustrated embodiments. The valve control arrangement 11 comprises a fluid component 18 with 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 assembly 11 includes a valve actuator 19 . According to the illustrated embodiments, the valve actuator 19 includes the cam lobes disposed on a camshaft 17 . According to further embodiments, the valve actuator can comprise a rocker arm, which can be connected to a camshaft via one or more push rods or the like, for example. The fluid component 18 and the fluid chamber 13 are arranged between the valve actuator 19 and the at least one valve 9 . The valve actuator 19 is provided so that it bears against a portion 18.1 of the fluid component 18. The fluid component 18 is arranged to transmit movement from the valve actuator 19 to the valve 9 when fluid pressure is created in the fluid chamber 13 . The fluid component 18 is arranged so that it does not transmit movement from the valve actuator 19 to the valve 9 when fluid pressure is not created in the fluid chamber 13 . According to the illustrated embodiments, the fluid pressure in the fluid chamber 13 is created by closing a first control valve 24 so that the movement of the valve actuator 19 can build up a fluid pressure in the fluid chamber 13 to thereby transmit the movement from the valve actuator 19 to the valve 9, as explained in more detail below.

The internal combustion engine 1 comprises a decompression brake arrangement 21. The decompression brake arrangement 21 is designed to selectively carry out decompression braking of the internal combustion engine 1. According to the illustrated embodiments, the valve control arrangement 11 is part of the compression brake arrangement 21. The valve control arrangement 11 is designed to selectively open the exhaust valve 9 into the at least one cylinder 3.1 near the end of the compression stroke of the engine 1. As a result, the energy stored in the compressed gases during the compression stroke is not returned to the crankshaft 7 during the subsequent expansion stroke, which increases the braking torque of the engine 1 . The valve control arrangement 11 is designed to selectively open the outlet valve 9 into the at least one cylinder 3.1 by creating a fluid pressure in the fluid chamber 13.

According to the illustrated embodiments, 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 circuit of pressurized fluid 28 and to the first control valve 24. According to the illustrated embodiments, the fluid circuit 28 is an oil circuit. The oil circuit can be part of an engine oil circuit of the engine 1 .

The engine 1 includes a control arrangement 23 designed to control at least the second control valve 26 . During a power generation state of the engine 1, the control arrangement 23 controls the second control valve 26 in a closed state. 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 an open state. When the first control valve 24 is in the open state, fluid such as oil can flow into and out of the fluid chamber 13 via the first control valve 24 upon rotation of the camshaft 17 . As a result, the movement of the valve actuator 19 is not transmitted to the outlet valve 9 . As a result, the valve actuator 19 will not force the outlet valve 9 to open when the second control valve 26 is in the closed state. According to the illustrated embodiments, however, the cam lobe 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 exhaust valve control assembly 12.2 is provided with a greater height than the valve actuator 19 and thereby has a greater stroke length than the valve actuator 19 and that the fluid component 18 is designed to accommodate the movement of the cam lobe 20.2 towards the exhaust valve 9 transferred when subjected to the stroke length of cam lobe 20.2. This allows the engine 1 in one be operated in the power-generating state when the second control valve 26 is in the closed state.

To initiate compression release braking, the compression release brake assembly 21 controls the second control valve 26 to an open state. In the open state, the second control valve 26 applies fluid pressure to the first control valve 24 . When fluid pressure is applied to the first control valve 24, the first control valve 24 assumes an active state. When active, the first control valve 24 allows fluid to flow into the fluid chamber 13 and prevents the fluid from exiting the fluid chamber 13 . As a result, upon rotation of the camshaft 17, the fluid chamber is filled with fluid. When the fluid chamber 13 is filled with fluid and the valve actuator 19 of the camshaft 17 presses on the section 18.1 of the fluid component 18, the force of the valve actuator 19 is transmitted to the exhaust valve 9 via the fluid component 18, which forces the exhaust valve 9 into the open position .

The internal combustion engine 1 includes a sensor 15 which is designed to measure the fluid pressure in the fluid chamber 13 . The exhaust valve 9 includes a certain surface area arranged to face the interior of the cylinder, and the fluid chamber 13 is provided with a certain cross-sectional area. Thus, the measured fluid pressure in the fluid chamber 13 provides a clear and reliable indication of the pressure in the cylinder 3.1 at the moment the outlet valve 9 opens based on the measured fluid pressure in the fluid chamber 13. In addition to the measured fluid pressure in the fluid chamber 13, the estimation of the pressure in the at least one cylinder 3.1 on the surface area of the outlet valve 9 facing the cylinder 3.1, the cross-sectional area of the fluid chamber 13, the speed of the internal combustion engine 1, friction losses, the pressure in the intake system 8, boost pressure of a charger, etc.

The control arrangement 23 is designed to open the at least one valve 9 in the at least one cylinder 3.1 when the piston 5 is in a region of top dead center, for example when the piston is within the interval of 20 crank angle degrees before top dead center to 20 crank angle degrees behind top dead center. The pressure in a cylinder of an engine is highest when the piston is at top dead center. The braking force of the engine 1 is increased by opening the at least one valve 9 in the at least one cylinder 3.1 when the piston 5 is in the region of top dead center. Furthermore, the estimation of the pressure in the cylinder 3.1 can be carried out reliably due to the high pressure. According to the illustrated embodiments, the control arrangement 23 is designed to open the at least one valve 9 in the at least one cylinder, to measure the fluid pressure in the fluid chamber 13 and the pressure in the at least one cylinder 3.1 based on the measured fluid pressure in the fluid chamber 13 to estimate during engine braking. According to further embodiments, the control arrangement 23 can alternatively or additionally be designed to open the at least one valve 9 in the at least one cylinder 3.1, to measure the fluid pressure in the fluid chamber 13 and the pressure in the at least one cylinder 3.1 based on the measured fluid pressure in the fluid chamber 13 during the running and/or starting of the engine 1.

According to some embodiments, the control arrangement 23 may be configured to open the at least one valve 9 in the at least one cylinder 3.1 when the piston 5 is at a distance from bottom dead center by performing a phase shift of the exhaust valve control arrangement 12.2. The cam lobe 20.2 of the exhaust valve control arrangement 12.2 forces the exhaust valve 9 to open when the piston 5 is at a distance from bottom dead center and the pressure in the at least one cylinder 3.1 can be estimated based on the measured fluid pressure in the fluid chamber 13. According to such embodiments, engine 1 may include a phase shifting device instead of or in addition to compression brake assembly 21 .

2 shows schematically a side view of the in 1 illustrated internal combustion engine 1. The internal combustion engine 1 comprises six cylinders arranged in series 3.1 - 3.6. the inside 2 The engine shown can therefore be described as a six-cylinder in-line engine. The internal combustion engine 1 may comprise a number of cylinders other than six, which may be arranged in a configuration other than in-line, as will be explained in more detail below. the inside 1 Cylinder 3.1 shown is the first cylinder 3.1 of the in 2 illustrated six cylinders 3.1 - 3.6. The remaining cylinders 3.2 - 3.6 of the six cylinders 3.1 - 3.6 each comprise a piston, at least one valve arranged in the cylinder 3.2 - 3.6, the at least one valve being arranged for controlling the gas flow into and/or out of the cylinder 3.2 - 3.6 , and a valve control assembly provided with a fluid component including a fluid chamber. The second control valve 24 of the compression release brake assembly 21 is over a fluid connection fluidly connected to each fluid chamber of each cylinder 3.1 - 3.6. the inside 1 The sensor 15 shown is designed to measure the fluid pressure p in the fluid connection. As a result, the fluid pressure in each fluid chamber can be detected using a sensor 15 . In embodiments where the engine includes cylinders arranged in more than one bank, such as in a V-configuration engine, the engine may include one sensor 15 per cylinder bank. Accordingly, a V-configuration engine may include two sensors 15 .

3 shows a diagram showing a series of successive pressure increase events p1 - p6 of the measured fluid pressure p in the fluid chambers 13 of the internal combustion engine 1, shown in 1 and 2 , represents. The vertical axis of the diagram shows the fluid pressure p and the horizontal axis shows the rotational position a of the crankshaft 7 of the engine 1.

According to the shown embodiments, the control arrangement 23 is designed to monitor a series of consecutive pressure increase events p1 - p6 of the measured fluid pressure p and a correlation between one or more consecutive pressure increase events p1 - p6 and one of the at least two cylinders 3.1 - 3.6 by comparing the consecutive ones Identify pressure increase events p1 - p6 with the crank angle a of the crankshaft 7 . The comparison between the consecutive pressure increase events p1 - p6 and the crank angle α of the crankshaft 7 can include a comparison between the position of the consecutive pressure increase events p1 - p6 and the crank angle α of the crankshaft 7 . As a result, a cylinder with a different cylinder pressure can be identified efficiently, reliably and cost-effectively. Furthermore, conditions are provided to estimate the pressure in two or more cylinders of an internal combustion engine with only one sensor.

Furthermore, the control arrangement, as in 3 shown, compare each pressure increase event p1 - p6 with a first threshold value t1 and a second threshold value t2. In such embodiments, the control arrangement 23 may determine under-cylinder pressure of a cylinder when the peak of a pressure increase event p1-p6 is below the first threshold t1. In 3 the pressure increase event p5 is below the first threshold value. According to the illustrated embodiments, the pressure increase event p5 belongs to the cylinder 3.5, which, as explained above, can be identified by comparing the successive pressure increase events p1-p6 with the crank angle α of the crankshaft 7. The control arrangement 23 may determine over-pressurization of a cylinder when the peak of an increase-in-pressurization event p1-p6 is above the second threshold t2. Excessive cylinder pressure can be caused by a worn camshaft, which can cause one or more valves to open too late. The control arrangement 23 can issue an alarm in a driver's environment of a vehicle comprising the internal combustion engine 1 if the estimated cylinder pressure is above the second threshold value t2 and/or below the first threshold value t1. The first and/or second threshold value t1, t2 can be determined from the speed of the internal combustion engine 1, friction losses, the pressure in the intake system 8, the charging pressure of a charging device, etc.

According to further embodiments, the control arrangement 23 can determine a cylinder pressure that 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 differ significantly from the other pressure increase events p1 - p6. This allows a cylinder with too high or too low cylinder pressure to be detected easily, effectively and reliably.

Furthermore, according to some embodiments, the control arrangement 23 can be designed to compare the phase and/or duration of the monitored pressure increase events p1-p6 with stored and/or predefined values for the phase and/or duration of the pressure increase events. As a result, a control arrangement 23 can be provided with an improved ability to detect whether components of the engine 1 have been subjected to wear which affects the compression ratio in the cylinders of the engine 1 .

4 shows a vehicle 25, the wheels 27 and the in 1 and 2 internal combustion engine 1 shown includes. The internal combustion engine 1 is designed to supply a driving force to the vehicle 25 via one or more of the wheels 27 of the vehicle 25 .

This in 4 vehicle 25 shown is a truck. However, the engine 1 may be incorporated in any other type of manned or unmanned vehicle for land or water propulsion, such as a truck, bus, construction vehicle, tractor, car, boat, ship or the like. Further, the engine 1 mentioned herein may be a stationary engine, for example, an engine of an engine-driven generator.

• - den mindestens einen Zylinder 3.1 - 3.6,
• - einen in jedem Zylinder 3.1 - 3.6 angeordneten Kolben 5,
• - eine Kurbelwelle 7,
• - mindestens ein Ventil 9, das in jedem Zylinder 3.1 - 3.6 angeordnet ist, wobei das mindestens eine Ventil 9 dafür vorgesehen ist, Gasströmung in den und/oder aus dem Zylinder 3.1 - 3.6 zu steuern,
• - eine Ventilsteueranordnung 11 mit einer Fluidkammer 13 und
• - einen Sensor 15, der dazu ausgelegt ist, den Fluiddruck p in der Fluidkammer 13 zu messen,

wobei das Verfahren 100 die Schritte umfasst von:

• - selektivem Öffnen 110 des mindestens einen Ventils 9 in den mindestens einen Zylinder 3.1 - 3.6 durch Schaffen eines Fluiddrucks p in der Fluidkammer 13,
• - Messen des Fluiddrucks p in der Fluidkammer 13, und
• - Schätzen 130 des Drucks in dem mindestens einen Zylinder 3.1 - 3.6 basierend auf dem gemessenen Fluiddruck p in der Fluidkammer 13.

5 10 shows a method 100 for 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 1 and 2 be illustrated embodiments. In addition, some features and advantages are illustrated by 3 explained. Therefore, the following 1 , 2 such as 3 referenced. The method 100 is a method for estimating a pressure in at least one cylinder 3.1-3.6 of an internal combustion engine 1, the internal combustion engine 1 comprising:

• - the 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, which at least one valve 9 is intended to control gas flow into and/or out of the cylinder 3.1 - 3.6,
• - A valve control assembly 11 having a fluid chamber 13 and
• - a sensor 15 designed to measure the fluid pressure p in the fluid chamber 13,

the method 100 comprising the steps of:

• - selective opening 110 of the at least one valve 9 in the at least one cylinder 3.1 - 3.6 by creating a fluid pressure p in the fluid chamber 13,
• - measuring the fluid pressure p in the fluid chamber 13, and
• - Estimating 130 the pressure in the at least one cylinder 3.1-3.6 based on the measured fluid pressure p in the fluid chamber 13.

• - Öffnen 111 des mindestens einen Ventils 9 in den mindestens einen Zylinder 3.1 - 3.6, wenn sich der Kolben 5 in einem Bereich des oberen Totpunktes befindet.

According to some embodiments, the piston 5 is arranged to reciprocate in the at least one cylinder 3.1 - 3.6 between a bottom dead center and a top dead center, the method 100 comprising the step of:

• - Opening 111 of the at least one valve 9 in the at least one cylinder 3.1 - 3.6 when the piston 5 is in a region of top dead center.

According to some embodiments, the valve control arrangement 11 comprises a valve actuator 19 , the fluid chamber 13 being arranged between the valve actuator 19 and the at least one valve 9 .

According to some embodiments, the method 100 is performed during engine braking of the internal combustion engine 1 , during running of the internal combustion engine 1 , or during starting of the internal combustion engine 1 .

According to some embodiments, the internal combustion engine 1 comprises a decompression braking arrangement 21 comprising the valve control arrangement 11, wherein the decompression braking arrangement 21 is configured to selectively perform decompression braking of the internal combustion engine 1, and wherein the method 100 is performed during the decompression braking.

• - Überwachen 140 einer Reihe von aufeinanderfolgenden Druckerhöhungsereignissen p1 - p6 des gemessenen Fluiddrucks p und
• - Identifizieren 150 einer Korrelation zwischen einem oder mehreren aufeinanderfolgenden Druckerhöhungsereignissen p1 - p6 und einem der mindestens zwei Zylinder 3.1 - 3.6 durch Vergleichen der aufeinanderfolgenden Druckerhöhungsereignisse p1 - p6 mit dem Kurbelwinkel a der Kurbelwelle 7.

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

• - monitoring 140 a series of consecutive pressure increase events p1 - p6 of the measured fluid pressure p and
• - Identifying 150 a correlation between one or more consecutive pressure increase events p1-p6 and one of the at least two cylinders 3.1-3.6 by comparing the consecutive pressure increase events p1-p6 with the crank angle a of the crankshaft 7.

It should be noted that the various embodiments described for the method 100 can all be combined with the control arrangement 23 described herein. This means that the control arrangement 23 can be designed to carry out one of the method steps 110 , 120 , 130 , 140 , 150 and 111 of the method 100 . Furthermore, the method 100 described herein can be performed during engine braking, while running and/or during starting of the internal combustion engine 1 .

6 10 shows a computer-readable medium 200 having instructions that, when executed by a computer, cause the computer to perform method 100, in accordance with some embodiments.

According to some embodiments, the computer-readable medium 200 includes a computer program having instructions that, when executed by a computer, cause the computer to perform the method 100 according to some embodiments.

Those skilled in the art will understand that the method for estimating a pressure in at least one cylinder of an internal combustion engine programmed instructions can be implemented. These programmed instructions typically consist of a computer program which, when executed in the control arrangement 23, ensures that the control arrangement 23 performs the desired control, such as method steps 110, 120, 130, 140, 150 and 111 described herein Usually part of a computer program product 200, comprising a suitable digital storage medium on which the computer program is stored.

The control arrangement 23 may comprise a computing unit, which may take the form of essentially any type of processor circuit or microcomputer, e.g. a digital signal processing circuit (digital signal processor, DSP), a central processing unit (CPU), a processing unit, a processing circuit, a Processor, an application-specific integrated circuit (ASIC), microprocessor, or other processing logic that can interpret and execute instructions. As used herein, the term "processing unit" may represent processing circuitry that includes a plurality of processing circuits, such as one, more, or all of the above.

The control arrangement 23 can also include a storage unit, wherein the processing unit can be connected to the storage unit, which can provide the processing unit with stored program code and/or stored data, for example, which the processing unit may need in order to be able to carry out calculations. The computing unit can also be designed to store partial or final results of calculations in the memory unit. The storage unit may comprise a physical device used for temporarily or permanently storing data or programs, i.e. sequences of instructions. According to some embodiments, the memory unit may include integrated circuits with silicon-based transistors. The memory device can, in various embodiments, be, for example, a memory card, a flash memory, a USB memory, a hard disk or other similar volatile or non-volatile memory device for storing data, such as ROM (Read-Only Memory), PROM (Programmable Read- Only Memory), EPROM (Erasable PROM), EEPROM (Electrically Erasable PROM), etc.

The control arrangement 23 is connected to components of the internal combustion engine 1 for receiving and/or sending input and output signals. These input and output signals may comprise waveforms, pulses or other attributes which the input signal receiving devices can detect as information and which can be converted into signals which can be processed by the control arrangement 23. These signals can then be fed to the computing unit.

One or more output signal transmission devices may be arranged to convert calculation results from the calculation unit into output signals which are forwarded to other parts of the vehicle's control system and/or the component(s) for which the signals are intended. Each of the connections to the respective components of the internal combustion engine 1 for receiving and sending input and output signals can take the form of one or more of a cable, a data bus, e.g. a CAN (Controller Area Network) bus, a MOST (Media Oriented Systems Transport) bus or other bus configuration or wireless connection. In the illustrated embodiments, the internal combustion engine 1 comprises a control arrangement 23, but can alternatively also be fully or partially implemented in two or more control arrangements or two or more control units.

Control systems in modern vehicles generally include a communication bus system, which includes one or more communication buses to connect a number of electronic control units (ECU) or controllers to various components on board the vehicle. Such a control system can consist of a large number of control units and the execution of a certain function can be shared between two or more of them. Vehicles of the type considered here are therefore often equipped with significantly more control arrangements than in 1 shown, which the person skilled in the art will certainly understand.

The computer program product 200 can be provided, for example, in the form of a data medium that contains computer program code for executing at least some of the method steps 110, 120, 130, 140, 150 and 111 according to some embodiments, when it is loaded into one or more computing units of the control arrangement 23 . The data medium can be a CD-ROM disk, for example, as in 6 shown, 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 disk, a memory stick , an optical storage device, a magnetic storage device, or any other suitable medium such as a hard disk or tape be capable of permanently storing machine-readable data. The computer program product can also be provided as computer program code on a server and downloaded to the control arrangement 23 remotely, eg via an Internet or intranet connection or via other wired or wireless communication systems.

It is to be understood that the foregoing shows various exemplary embodiments and that the invention is defined only by the appended claims. Those skilled in the art will recognize that the exemplary embodiments may be modified and that various features of the exemplary embodiments may be combined into embodiments other than those described herein without departing from the scope of disclosure of the present invention as defined by the appended claims. As discussed above, according to some embodiments, the fluid chamber and fluid component may include a hydraulic chamber and a hydraulic component. So in this revelation the word "fluid" can be replaced by the word "hydraulic" or by the word "liquid". For example, the hydraulic chamber and a hydraulic component may be part of a cylinder deactivation arrangement using hydraulic fluid or an idle arrangement using hydraulic fluid.

The cylinders 3.1 - 3.6 each form a combustion chamber. Thus, throughout this revelation, the word "cylinder" may be substituted for the word "combustion chamber." As used herein, the term "comprising" or "comprising" is open-ended and includes one or more specified features, elements, steps, components or functions, but does not exclude the presence or addition of one or more other features, elements, steps, components, functions or groups.

Claims (15)

Method (100) for estimating a pressure in at least one cylinder (3.1 - 3.6) of an internal combustion engine (1), the internal combustion engine (1) comprising: - the at least one cylinder (3.1 - 3.6), - a piston (5) placed in each cylinder (3.1 - 3.6), - a crankshaft (7), - at least one valve (9) arranged in each cylinder (3.1 - 3.6), said at least one valve (9) being intended to control gas flow 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) adapted to measure the fluid pressure (p) in the fluid chamber (13), the method (100) comprising the steps of: - selective opening (110) of the at least one valve (9) in the at least one cylinder (3.1 - 3.6) by creating a fluid pressure (p) in the fluid chamber (13), - Measuring (120) the fluid pressure (p) in the fluid chamber (13) and - Estimating (130) the pressure in the at least one cylinder (3.1 - 3.6) based on the measured fluid pressure (p) in the fluid chamber (13). Method (100) according to claim 1 , wherein the piston (5) is arranged to be reciprocated in the at least one cylinder (3.1 - 3.6) between a bottom dead center and a top dead center, the method (100) comprising the step of: - opening (111) of the at least one valve (9) into the at least one cylinder (3.1 - 3.6) when the piston (5) is in a region of top dead center. Method (100) according to claim 1 or 2 wherein the valve control arrangement (11) comprises a valve actuator (19) and wherein the fluid chamber (13) is arranged between the valve actuator (19) and the at least one valve (9). Method (100) according to any one of Claims 1 - 3 , wherein the method (100) is carried out during engine braking of the internal combustion engine (1), while running the internal combustion engine (1) or during starting of the internal combustion engine (1). Method (100) according to one of the preceding claims, wherein the internal combustion engine (1) comprises a decompression brake arrangement (21) which comprises the valve control arrangement (11), the decompression brake arrangement (21) being designed to selectively carry out decompression braking of the internal combustion engine (1). , and wherein the method (100) is performed during compression release braking. Method (100) according to any one of the preceding claims, wherein the internal combustion engine (1) comprises at least two cylinders (3.1 - 3.6) and a crank angle sensor (22), the method (100) comprising the steps of: - monitoring (140) a series of consecutive pressure increase events (p1-p6) of the measured fluid pressure (p), and - identifying (150) a correlation between one or more consecutive pressures Boost events (p1 - p6) and one of the at least two cylinders (3.1 - 3.6) by comparing the successive pressure increase events (p1 - p6) with the crank angle (a) of the crankshaft (7). A computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out the method (100) according to any one of Claims 1 - 6 performs. A computer-readable medium (200) comprising instructions which, when executed by a computer, cause the computer to perform the method (100) of any one of Claims 1 - 6 executes Control arrangement (23) designed to estimate a pressure in at least one cylinder (3.1 - 3.6) of an internal combustion engine (1), the internal combustion engine (1) comprising: - the at least one cylinder (3.1 - 3.6), - a piston (5) placed in each cylinder (3.1 - 3.6), - a crankshaft (7), - at least one valve (9) arranged in each cylinder (3.1 - 3.6), the at least one valve (9) being intended to control the gas flow 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) adapted to measure the fluid pressure (p) in the fluid chamber (13), the control arrangement (23) being adapted to: - selectively opening the at least one valve (9) in the at least one cylinder (3.1 - 3.6) by creating a fluid pressure (p) in the fluid chamber (13), - Measuring the fluid pressure (p) in the fluid chamber (13) and - Estimating the pressure in the at least one cylinder (3.1 - 3.6) based on the measured fluid pressure (p) in the fluid chamber (13). Internal combustion engine (1) comprising: - at least one cylinder (3.1 - 3.6), - a piston (5) placed in each cylinder (3.1 - 3.6), - a crankshaft (7), - at least one valve (9) arranged in each cylinder (3.1 - 3.6), the at least one valve (9) being intended to control the gas flow into and/or out of the cylinder (3.1 - 3.6), - a valve control arrangement (11) comprising a fluid chamber (13), - a sensor (15) adapted to measure the fluid pressure (p) in the fluid chamber (13), and - a control arrangement (23) designed to: - selectively opening the at least one valve (9) in the at least one cylinder (3.1 - 3.6) by creating a fluid pressure (p) in the fluid chamber (13), - Measuring the fluid pressure (p) in the fluid chamber (13) and - Estimating the pressure in the at least one cylinder (3.1 - 3.6) based on the measured fluid pressure (p) in the fluid chamber (13). Combustion engine (1) after claim 10 , wherein the piston (5) is designed to be moved back and forth in the at least one cylinder (3.1 - 3.6) between a bottom dead center and a top dead center, the control arrangement (23) being designed for: - opening the at least a valve (9) in the at least one cylinder (3.1 - 3.6) when the piston (5) is in a region of top dead center. Combustion engine (1) after claim 10 or 11 wherein the valve control arrangement (11) comprises a valve actuator (19) and wherein the fluid chamber (13) is arranged between the valve actuator (19) and the at least one valve (9). Internal combustion engine (1) according to one of Claims 10 - 12 , wherein the internal combustion engine (1) comprises a decompression brake assembly (21) comprising the valve control assembly (11). Internal combustion engine (1) according to one of Claims 10 - 13 , wherein the internal combustion engine (1) comprises at least two cylinders (3.1 - 3.6) and a crank angle sensor (22), wherein the control arrangement (23) is designed for: - monitoring a series of consecutive pressure increase events (p1 - p6) of the measured fluid pressure (p ) and - identifying a correlation between one or more consecutive pressure increase events (p1 - p6) and one of the at least two cylinders (3.1 - 3.6) by comparing the consecutive pressure increase events (p1 - p6) with the crank angle (a) of the crankshaft (7). Vehicle (25), the wheels (27) and an internal combustion engine (1) according to one of Claims 10 - 14 comprises, wherein the internal combustion engine (1) is designed to provide a driving force to the vehicle (25) via one or more of the wheels (27) of the vehicle (25).

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