Method and control arrangement for diagnosing a camshaft bearing assembly

Abstract

A method (100) of diagnosing a camshaft bearing assembly (3) of an internal combustion engine (1) is disclosed. The engine (1) comprises a crankshaft (4), a hydraulic cam phase shifting arrangement (5), and a camshaft (6) rotationally arranged via the camshaft bearing assembly (3) and rotationally coupled to the crankshaft (4) via the hydraulic cam phase shifting arrangement (5). The method (100) comprises the steps of monitoring (110) the rate of change of the phase angle when the hydraulic cam phase shifting arrangement (5) is adjusting the phase angle, and diagnosing (120) an operational performance of the camshaft bearing assembly (3) based on the monitored rate of change of the phase angle. The present disclosure further relates to a computer program, a computer-readable medium (200), a control arrangement (21), an internal combustion engine (1), and a vehicle (2).

Description

[0001] Method of Diagnosing a Camshaft Bearing Assembly, Computer Program, Computer-Readable Medium, Control Arrangement, Internal Combustion Engine, and Vehicle

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to a method of diagnosing a camshaft bearing assembly of an internal combustion engine. The present disclosure further relates to a computer program, a computer-readable medium, a control arrangement for an internal combustion engine, an internal combustion engine comprising a control arrangement, and a vehicle comprising an internal combustion engine.

[0004] BACKGROUND

[0005] Internal combustion engines can be used to provide motive power to a vehicle. Such engines typically comprise one or more cylinders, each having a piston that is arranged to reciprocate within the cylinder. The pistons are connected to a crankshaft, which converts the reciprocating motion of the pistons into rotational motion. The engine usually comprises one or more inlet and outlet valves to control the flow of gases into and out of the cylinders.

[0006] These valves are controlled by a camshaft, which is rotationally coupled to the crankshaft and is responsible for opening and closing the valves during engine operation.

[0007] A camshaft can be arranged within a cylinder head of the engine and comprises one or more cam lobes that act on the inlet and outlet valves. The camshaft is rotationally supported via a camshaft bearing assembly, which allows it to rotate while maintaining proper alignment within the engine. The camshaft is subjected to both positive and negative torques during operation, as the cam lobes engage with valve actuation mechanisms to open and close the valves, which causes fluctuations in torque as the camshaft rotates.

[0008] Many modern internal combustion engines further comprise a hydraulic cam phase shifting arrangement. Such an arrangement is typically positioned between the camshaft and the crankshaft and can be controlled to adjust a phase angle of the camshaft relative to the crankshaft. The hydraulic cam phase shifting arrangement usually comprises an actuator that is operated using hydraulic pressure to modify the position of the camshaft. This arrangement relies on the varying torque acting on the camshaft during valve actuation to shift the camshaft phase relative to the crankshaft. By adjusting the timing of the camshaft, the hydraulic cam phase shifting arrangement can provide improved engine efficiency and performance of the engine under varying operating conditions. For example, the timing ofvalve events can be modified to optimise fuel combustion, reduce emissions, and enhance torque delivery across different engine speeds.

[0009] Camshaft bearing failure can occur in an internal combustion engine and may lead to significant problems. A damaged or worn camshaft bearing assembly can cause increased friction and misalignment of the camshaft, which may affect the timing of the valves. This can result in a loss of engine efficiency, increased fuel consumption, and a reduction in engine performance. In some cases, the failure may lead to severe mechanical damage, requiring extensive repairs or replacement of components. If left unaddressed, the engine may become inoperable, resulting in Vehicle Off Road (VOR) until the necessary repairs are completed.

[0010] Detecting such failures before significant damage occurs can be difficult. In many cases, the first indication of a failing camshaft bearing assembly is a decline in engine performance. By the time these symptoms appear, the damage may already be extensive, requiring an inspection of the engine in a workshop. If additional components have been affected, the repair process may involve replacing multiple parts, increasing both material and labour costs.

[0011] Additionally, workshop availability and repair times can contribute to vehicle downtime. In commercial applications, where continuous operation is often required, prolonged downtime can lead to financial losses and operational disruptions. Since camshaft bearing failure can result in costly repairs and unplanned downtime, improvements in monitoring and detection of such failures could be beneficial for reducing vehicle downtime and maintenance costs.

[0012] SUMMARY

[0013] It is an object of the present invention to overcome, or at least alleviate, at least some of the above-mentioned problems and drawbacks. The object is achieved by the subject-matter of the appended independent claim(s).

[0014] According to a first aspect of the present disclosure, the object is achieved by a method of diagnosing a camshaft bearing assembly of an internal combustion engine, wherein the method is performed by a control arrangement, and wherein the engine comprises a crankshaft, a hydraulic cam phase shifting arrangement, and a camshaft rotationally arranged via the camshaft bearing assembly and rotationally coupled to the crankshaft via the hydraulic cam phase shifting arrangement. The hydraulic cam phase shiftingarrangement is controllable to adjust a phase angle of the camshaft relative to the crankshaft. The method comprises the steps of:

[0015] - monitoring the rate of change of the phase angle when the hydraulic cam phase shifting arrangement is adjusting the phase angle, and

[0016] - diagnosing an operational performance of the camshaft bearing assembly based on the monitored rate of change of the phase angle.

[0017] Thereby, a method is provided having conditions for diagnosing the operational performance of the camshaft bearing assembly in a simple and cost-efficient manner and enabling early detection of malfunctions in the camshaft bearing assembly. This is because, as realized by the inventor of the present solution, a shift in the rate of change of the phase angle upon adjustment of the phase angle by the hydraulic cam phase shifting arrangement can indicate an increase in resistive torque due to friction between the camshaft and the camshaft bearing assembly. An increase in resistive torque due to friction between the camshaft and the camshaft bearing assembly is early indication of an upcoming malfunction of the camshaft bearing assembly.

[0018] Thus, by diagnosing the operational performance of the camshaft bearing assembly based on the monitored rate of change of the phase angle, a method is provided capable of enabling early detection of potential problems that may otherwise remain unnoticed until significant damage has occurred. This can help prevent unexpected failures that could lead to Vehicle Off Road and costly repairs. By identifying deviations in the operational performance of the camshaft bearing assembly at an early stage, the method allows for more effective maintenance planning, reducing the risk of extensive engine damage and unplanned downtime.

[0019] Moreover, since camshaft bearing failure can affect valve timing and overall engine efficiency, diagnosing its operational performance can contribute to maintaining stable engine operation. Ensuring proper support of the camshaft can help sustain optimal valve timing, fuel efficiency, and emissions control. Additionally, early detection of performance deviations can allow corrective measures to be taken before severe mechanical damage occurs, potentially extending the service life of both the camshaft bearing assembly and other associated engine components.

[0020] In commercial applications, where vehicles are often required to operate with minimal downtime, the ability to diagnose the camshaft bearing assembly’s operational performance can improve reliability and enable cost-efficient maintenance planning. By reducing thelikelihood of unexpected failures and unplanned workshop visits, the method can contribute to lower maintenance costs and increased vehicle availability.

[0021] Accordingly, a method is provided overcoming, or at least alleviating, at least some of the above-mentioned problems and drawbacks. As a result, the above-mentioned object is achieved.

[0022] The term "phase angle of the camshaft relative to the crankshaft" as used herein means the angular position of the camshaft in relation to the rotational position of the crankshaft. This phase angle defines the timing of valve events relative to the engine cycle, as the camshaft controls the opening and closing of the engine’s valves while the crankshaft governs piston movement. Adjusting this phase angle alters valve timing, which can influence engine performance, efficiency, and emissions characteristics.

[0023] The feature “monitoring the rate of change of the phase angle when the hydraulic cam phase shifting arrangement is adjusting the phase angle”, as used herein, means that the rate of change of the phase angle is monitored during adjustment of the phase angle by the hydraulic cam phase shifting arrangement. The step of monitoring the rate of change of the phase angle may be initiated upon receipt of a signal indicating that the hydraulic cam phase shifting arrangement is, or is about to be, adjusting the phase angle.

[0024] Optionally, the method comprises:

[0025] - monitoring the retarding rate of the phase angle when the hydraulic cam phase shifting arrangement is retarding the phase angle, and

[0026] wherein the step of diagnosing the operational performance of the camshaft bearing assembly comprises:

[0027] - setting a fault indicator of the hydraulic cam phase shifting arrangement if the monitored retarding rate exceeds a first threshold.

[0028] Thereby, a method is provided having conditions for diagnosing the operational performance of the camshaft bearing assembly with improved accuracy. This is because, as realized by the inventor of the present solution, the retarding rate of the phase angle tends to increase with an increased resistive torque provided by the camshaft bearing assembly due to friction.

[0029] Thus, by setting the fault indicator of the hydraulic cam phase shifting arrangement if the monitored retarding rate exceeds the first threshold, the fault indicator can be set at instances in which the friction provided by the camshaft bearing assembly has increased,which is an early indication of an upcoming malfunction of the camshaft bearing assembly. Accordingly, in this manner, a method is provided having improved conditions for early detection of malfunctions in the camshaft bearing assembly.

[0030] The feature “monitoring the retarding rate of the phase angle when the hydraulic cam phase shifting arrangement is retarding the phase angle”, as used herein, means that the retarding rate of the phase angle is monitored while the hydraulic cam phase shifting arrangement is retarding the phase angle. The step monitoring the retarding rate of the phase angle may be initiated upon receipt of a signal indicating that the hydraulic cam phase shifting arrangement is, or is about to be, retarding the phase angle.

[0031] The term "retarding" in this context refers to shifting the phase angle of the camshaft in a direction that delays valve timing relative to the rotational position of the crankshaft. Since the crankshaft determines the phases of engine cycles, this also results in a delay relative to the engine cycles. The "retarding rate" refers to the rate at which this phase angle shift occurs over time, typically expressed in degrees per unit of time.

[0032] Optionally, the method comprises:

[0033] - monitoring the advancing rate of the phase angle when the hydraulic cam phase shifting arrangement is advancing the phase angle, and

[0034] wherein the step of diagnosing the operational performance of the camshaft bearing assembly comprises:

[0035] - setting a fault indicator of the hydraulic cam phase shifting arrangement if the monitored advancing rate is below a second threshold.

[0036] Thereby, a method is provided having conditions for diagnosing the operational performance of the camshaft bearing assembly with improved accuracy. This is because, as realized by the inventor of the present solution, the advancing rate of the phase angle tends to decline with an increased resistive torque provided by the camshaft bearing assembly due to friction.

[0037] Thus, by setting the fault indicator of the hydraulic cam phase shifting arrangement if the monitored advancing rate is below the second threshold, the fault indicator can be set at instances in which the friction provided by the camshaft bearing assembly has increased, which is an early indication of an upcoming malfunction of the camshaft bearing assembly. Accordingly, in this manner, a method is provided having improved conditions for early detection of malfunctions in the camshaft bearing assembly.The feature “monitoring the advancing rate of the phase angle when the hydraulic cam phase shifting arrangement is advancing the phase angle” as used herein means that the advancing rate of the phase angle is monitored while the hydraulic cam phase shifting arrangement is advancing the phase angle. The step of monitoring the advancing rate of the phase angle may be initiated upon receipt of a signal indicating that the hydraulic cam phase shifting arrangement is, or is about to be, advancing the phase angle.

[0038] The term "advancing" in this context refers to shifting the phase angle of the camshaft in a direction that causes valve timing to occur earlier relative to the rotational position of the crankshaft. Since the crankshaft determines the phases of engine cycles, this also results in an earlier timing relative to the engine cycles. The "advancing rate" refers to the rate at which this phase angle shift occurs overtime, typically expressed in degrees per unit of time.

[0039] Optionally, the method comprises:

[0040] - monitoring the retarding rate of the phase angle when the hydraulic cam phase shifting arrangement is retarding the phase angle, and

[0041] - monitoring the advancing rate of the phase angle when the hydraulic cam phase shifting arrangement is advancing the phase angle,

[0042] wherein the step of diagnosing the operational performance of the camshaft bearing assembly comprises:

[0043] - setting a fault indicator of the hydraulic cam phase shifting arrangement based on the difference between the monitored retarding rate and the monitored advancing rate.

[0044] Thereby, a method is provided having conditions for diagnosing the operational performance of the camshaft bearing assembly with further improved accuracy. This is because, as realized by the inventor of the present solution, the difference between the monitored retarding rate and the monitored advancing rate provides an indication of asymmetry in the phase shifting behaviour, which may be influenced by mechanical resistance, wear, or faults within the camshaft bearing assembly. Accordingly, by setting the fault indicator of the hydraulic cam phase shifting arrangement based on this difference, a method is provided having improved conditions for early detection of malfunctions in the camshaft bearing assembly.

[0045] Moreover, by setting the fault indicator based on the difference between the monitored retarding rate and the monitored advancing rate, the method can more reliably distinguish problems related to the camshaft bearing assembly from other types of faults, such as faults in the hydraulic cam phase shifting arrangement. Thus, in this manner, the method enhancesdiagnostic accuracy by identifying deviations in phase shifting behaviour that are indicative of issues specific to the camshaft bearing assembly. This can help prevent misinterpretation of faults and support more effective troubleshooting, potentially reducing unnecessary maintenance actions and component replacements.

[0046] As above, the term "retarding" refers to shifting the phase angle of the camshaft in a direction that delays valve timing relative to the rotational position of the crankshaft. The "retarding rate" refers to the rate at which this phase angle shift occurs over time, typically expressed in degrees per unit of time. Moreover, the term "advancing" refers to shifting the phase angle of the camshaft in a direction that causes valve timing to occur earlier relative to the rotational position of the crankshaft. The "advancing rate" refers to the rate at which this phase angle shift occurs over time, typically expressed in degrees per unit of time. The term "difference between the monitored retarding rate and the monitored advancing rate" refers to the deviation between the rate at which the camshaft phase angle is retarded and the rate at which it is advanced. This deviation may be numerical, such as a measured difference in degrees per unit of time, or expressed as a ratio between the two rates.

[0047] Optionally, the step of setting the fault indicator comprises:

[0048] - setting a fault indicator of the hydraulic cam phase shifting arrangement if the difference between the monitored retarding rate and the monitored advancing rate exceeds a threshold difference.

[0049] Thereby, a method is provided having conditions for diagnosing the operational performance of the camshaft bearing assembly with even further improved accuracy. This is because, as realized by the inventor of the present solution, an increase of the difference between the monitored retarding rate and the monitored advancing rate clearly indicates an increased resistive torque provided by the camshaft bearing assembly due to friction.

[0050] Thus, by setting the fault indicator if the difference between the monitored retarding rate and the monitored advancing rate exceeds the threshold difference, the fault indicator can be accurately set at instances in which the friction provided by the camshaft bearing assembly has increased, which is an early indication of an upcoming malfunction of the camshaft bearing assembly. Accordingly, in this manner, a method is provided having improved conditions for early detection of malfunctions in the camshaft bearing assembly. In addition, the method can more reliably distinguish problems related to the camshaft bearing assembly from other types of faults, such as faults in the hydraulic cam phase shifting arrangement. Thus, in this manner, the method enhances diagnostic accuracy by identifying deviations inphase shifting behaviour that are indicative of issues specific to the camshaft bearing assembly. This can help prevent misinterpretation of faults and support more effective troubleshooting, potentially reducing unnecessary maintenance actions and component replacements.

[0051] According to a second aspect of the present disclosure, the object is achieved by a computer program comprising instructions which, when the program is executed by a control arrangement of an internal combustion engine, cause the control arrangement to carry out the method according to the first aspect of the present disclosure. Since the computer program comprises instructions to cause the control arrangement to carry out the method according to the first aspect of the present disclosure, a computer program is provided which provides conditions for overcoming, or at least alleviating, at least some of the above-mentioned drawbacks. As a result, the above-mentioned object is achieved.

[0052] According to a third aspect of the present disclosure, the object is achieved by a computer-readable medium comprising instructions which, when executed by a control arrangement of an internal combustion engine, cause the control arrangement to carry out the method according to the first aspect of the present disclosure. Since the computer-readable medium comprises instructions which, when executed by the control arrangement, cause the control arrangement to carry out the method according to the first aspect of the present disclosure, a computer-readable medium is provided which provides conditions for overcoming, or at least alleviating, at least some of the above-mentioned drawbacks. As a result, the above-mentioned object is achieved.

[0053] According to a fourth aspect of the present disclosure, the object is achieved by a control arrangement for an internal combustion engine, wherein the engine comprises a crankshaft, a hydraulic cam phase shifting arrangement, a camshaft bearing assembly, and a camshaft rotationally arranged via the camshaft bearing assembly and rotationally coupled to the crankshaft via the hydraulic cam phase shifting arrangement. The hydraulic cam phase shifting arrangement is controllable to adjust a phase angle of the camshaft relative to the crankshaft. The control arrangement is configured to:

[0054] - monitor the rate of change of the phase angle when the hydraulic cam phase shifting arrangement is adjusting the phase angle, and

[0055] - diagnose an operational performance of the camshaft bearing assembly based on the monitored rate of change of the phase angle.Thereby, a control arrangement is provided having conditions for diagnosing the operational performance of the camshaft bearing assembly in a simple and cost-efficient manner and enabling early detection of malfunctions in the camshaft bearing assembly. This is because, as realized by the inventor of the present solution, a shift in the rate of change of the phase angle upon adjustment of the phase angle by the hydraulic cam phase shifting arrangement can indicate an increase in resistive torque due to friction between the camshaft and the camshaft bearing assembly. An increase in resistive torque due to friction between the camshaft and the camshaft bearing assembly is early indication of an upcoming malfunction of the camshaft bearing assembly.

[0056] Thus, by diagnosing the operational performance of the camshaft bearing assembly based on the monitored rate of change of the phase angle, a control arrangement is provided capable of enabling early detection of potential problems that may otherwise remain unnoticed until significant damage has occurred. This can help prevent unexpected failures that could lead to Vehicle Off Road and costly repairs. By identifying deviations in the operational performance of the camshaft bearing assembly at an early stage, the control arrangement allows for more effective maintenance planning, reducing the risk of extensive engine damage and unplanned downtime.

[0057] Since camshaft bearing failure can affect valve timing and overall engine efficiency, diagnosing its operational performance can contribute to maintaining stable engine operation. Ensuring proper support of the camshaft can help sustain optimal valve timing, fuel efficiency, and emissions control. Additionally, early detection of performance deviations can allow corrective measures to be taken before severe mechanical damage occurs, potentially extending the service life of both the camshaft bearing assembly and other associated engine components.

[0058] In commercial applications, where vehicles are often required to operate with minimal downtime, the ability to diagnose the camshaft bearing assembly’s operational performance can improve reliability and enable cost-efficient maintenance planning. By reducing the likelihood of unexpected failures and unplanned workshop visits, the control arrangement can contribute to lower maintenance costs and increased vehicle availability.

[0059] Accordingly, a control arrangement is provided overcoming, or at least alleviating, at least some of the above-mentioned problems and drawbacks. As a result, the above-mentioned object is achieved.It will be appreciated that the various embodiments described for the method are all combinable with the control arrangement as described herein. That is, the control arrangement according to the fourth aspect of the invention may be configured to perform any one of the method steps of the method according to the first aspect of the invention.

[0060] According to a fifth aspect of the present disclosure, the object is achieved by an internal combustion engine comprising a crankshaft, a hydraulic cam phase shifting arrangement, a camshaft bearing assembly, and a camshaft rotationally arranged via the camshaft bearing assembly and rotationally coupled to the crankshaft via the hydraulic cam phase shifting arrangement. The hydraulic cam phase shifting arrangement is controllable to adjust a phase angle of the camshaft relative to the crankshaft. The internal combustion engine comprises a control arrangement according to the fourth aspect of the present disclosure.

[0061] Thereby, an internal combustion engine is provided that enables a simple and cost-efficient approach for diagnosing the operational performance of the camshaft bearing assembly, while allowing for early detection of malfunctions. This is because, as realized by the inventor of the present solution, a shift in the rate of change of the phase angle upon adjustment of the phase angle by the hydraulic cam phase shifting arrangement can indicate an increase in resistive torque due to friction between the camshaft and the camshaft bearing assembly.

[0062] Thus, by incorporating a control arrangement configured to diagnose the operational performance of the camshaft bearing assembly based on the monitored rate of change of the phase angle, the internal combustion engine enables early detection of potential problems that may otherwise remain unnoticed until significant damage has occurred. This can help prevent unexpected failures that could lead to Vehicle Off Road and costly repairs. By identifying deviations in the operational performance of the camshaft bearing assembly at an early stage, the engine allows for more effective maintenance planning, reducing the risk of extensive engine damage and unplanned downtime.

[0063] Since failures in camshaft bearing assemblies can affect valve timing and overall engine efficiency, diagnosing its operational performance contributes to maintaining stable engine operation. Moreover, ensuring proper support of the camshaft can help sustain optimal valve timing, fuel efficiency, and emissions control. Additionally, early detection of performance deviations allows for corrective measures to be taken before severe mechanical damage occurs, potentially extending the service life of both the camshaft bearing assembly and other associated engine components.In commercial applications, where vehicles are often required to operate with minimal downtime, an internal combustion engine incorporating a control arrangement for diagnosing the camshaft bearing assembly’s operational performance can improve reliability and support cost-efficient maintenance planning. By reducing the likelihood of unexpected failures and unplanned workshop visits, the engine can contribute to lower maintenance costs and increased vehicle availability.

[0064] Accordingly, an internal combustion engine is provided that overcomes, or at least alleviates, at least some of the above-mentioned problems and drawbacks. As a result, the above-mentioned object is achieved.

[0065] According to a sixth aspect of the present disclosure, the object is achieved by a vehicle comprising an internal combustion engine according to the fifth aspect of the present disclosure.

[0066] Thereby, a vehicle is provided that enables a simple and cost-efficient approach for diagnosing the operational performance of the camshaft bearing assembly, while allowing for early detection of malfunctions in the internal combustion engine. This is because, as realized by the inventor of the present solution, a shift in the rate of change of the phase angle upon adjustment of the phase angle by the hydraulic cam phase shifting arrangement can indicate an increase in resistive torque due to friction between the camshaft and the camshaft bearing assembly.

[0067] Thus, by incorporating an internal combustion engine configured to diagnose the operational performance of the camshaft bearing assembly based on the monitored rate of change of the phase angle, the vehicle enables early detection of potential problems that may otherwise remain unnoticed until significant damage has occurred. This can help prevent unexpected failures that could lead to Vehicle Off Road and costly repairs. By identifying deviations in the operational performance of the camshaft bearing assembly at an early stage, the vehicle allows for more effective maintenance planning, reducing the risk of extensive engine damage and unplanned downtime.

[0068] Since failures in camshaft bearing assemblies can affect valve timing and overall engine efficiency, diagnosing its operational performance contributes to maintaining stable engine operation. Ensuring proper support of the camshaft can help sustain optimal valve timing, fuel efficiency, and emissions control. Additionally, early detection of performance deviations allows for corrective measures to be taken before severe mechanical damage occurs,potentially extending the service life of both the camshaft bearing assembly and other associated engine components.

[0069] In commercial applications, where vehicles are often required to operate with minimal downtime, a vehicle incorporating an internal combustion engine with a control arrangement for diagnosing the camshaft bearing assembly’s operational performance can improve reliability and support cost-efficient maintenance planning. By reducing the likelihood of unexpected failures and unplanned workshop visits, the vehicle can contribute to lower maintenance costs and increased operational availability.

[0070] Accordingly, a vehicle is provided that overcomes, or at least alleviates, at least some of the above-mentioned problems and drawbacks. As a result, the above-mentioned object is achieved.

[0071] Optionally, the vehicle is a heavy wheeled vehicle. Thereby, a heavy wheeled vehicle is provided having at least some of the above-mentioned advantages.

[0072] Further features of, and advantages with, the present invention will become apparent when studying the appended claims and the following detailed description.

[0073] BRIEF DESCRIPTION OF THE DRAWINGS

[0074] Various aspects of the present disclosure, including its particular features and advantages, will be readily understood from the example embodiments discussed in the following detailed description and the accompanying drawings, in which:

[0075] Fig. 1 schematically illustrates a vehicle according to some embodiments of the present disclosure,

[0076] Fig. 2 schematically illustrates an internal combustion engine of the vehicle illustrated in Fig.

[0077] 1,

[0078] Fig. 3 schematically illustrates a camshaft assembly of the internal combustion engine illustrated in Fig. 2,

[0079] Fig. 4 schematically illustrates a cross-section of a hydraulic cam phase shifting arrangement of the camshaft assembly illustrated in Fig. 3,

[0080] Fig. 5 illustrates the cross-section of the hydraulic cam phase shifting arrangement illustrated in Fig. 4, in which the hydraulic cam phase shifting arrangement has advanced the phase angle of a camshaft relative to a crankshaft of the engine,Fig. 6 illustrates the cross-section of the hydraulic cam phase shifting arrangement illustrated in Fig. 5, in which the hydraulic cam phase shifting arrangement has retarded the phase angle of the camshaft relative to the crankshaft,

[0081] Fig. 7 illustrates first a graph showing a crankshaft torque as a function of time during rotation of the crankshaft,

[0082] Fig. 8 illustrates second a graph showing a crankshaft torque as a function of time during rotation of the crankshaft,

[0083] Fig. 9 schematically illustrates a method of diagnosing a camshaft bearing assembly of an internal combustion engine, and

[0084] Fig. 10 illustrates a computer-readable medium.

[0085] DETAILED DESCRIPTION

[0086] Aspects of the present disclosure will now be described more fully. Like reference signs refer to like elements throughout. Well-known functions or constructions will not necessarily be described in detail for brevity and / or clarity.

[0087] Fig. 1 schematically illustrates a vehicle 2 according to some embodiments of the present disclosure. According to the illustrated embodiments, the vehicle 2 is a truck, i.e. a type of heavy wheeled vehicle, a type of heavy road vehicle, as well as a type of heavy commercial vehicle. According to further embodiments, the vehicle 2, as referred to herein, may be another type of heavy or lighter type of manned or unmanned vehicle for land- or waterbased propulsion such as a lorry, a bus, a construction vehicle, a tractor, a car, a boat, a ship, or the like.

[0088] The vehicle 2 comprises an internal combustion engine 1. According to the illustrated embodiments, the internal combustion engine 1 is configured to provide motive power to the vehicle 2 via wheels 27 of the vehicle 2. The vehicle 2 may comprise one or more electric propulsion motors in addition to the internal combustion engine 1 for providing motive power to the vehicle 2. Thus, the vehicle 2 may comprise a so-called hybrid electric powertrain comprising one or more electric propulsion motors in addition to the internal combustion engine 1 for providing motive power to the vehicle 2. For reasons of brevity and clarity, the internal combustion engine 1 is in some places herein simply referred to as “the engine 1” or “the combustion engine 1”.

[0089] In Fig. 1, an occupant compartment 55 of the vehicle 2 is indicated. The occupant compartment 55 refers to the space intended to accommodate an operator and possibly also a number of occupants of the vehicle 2. According to some embodiments, the occupantcompartment 55 may include features such as seating arrangements, control interfaces, and displays for the operator. The occupant compartment 55 may also house various systems and components related to vehicle operation, such as a dashboard, steering mechanism, and controls for the engine 1 and other powertrain systems.

[0090] Fig. 2 schematically illustrates the internal combustion engine 1 of the vehicle 2 illustrated in Fig. 1. The engine 1 comprises a plurality of cylinders c1, c2, c3, c4, c5, c6 as schematically indicated in Fig. 2. The reference sign for the cylinders c1, c2, c3, c4, c5, c6 of the engine 1 is in some places herein abbreviated c1-c6 for reasons of brevity and clarity,

[0091] According to the illustrated embodiments, the engine 1 comprises six cylinders c1-c6 arranged in one row. The engine 1 according to the illustrated embodiments may therefore be referred to as an inline-six engine. However, according to further embodiments, the engine 1 , as referred to herein, may comprise another number of cylinders c1 -c6, such as one or more cylinders c1-c6. Moreover, the cylinders c1-c6 of the engine 1 may be arranged in another configuration than in one row, such as in two or more rows.

[0092] According to the illustrated embodiments, the internal combustion engine 1 is an Otto engine with a spark-ignition device, wherein the Otto engine may be configured to run on petrol, alcohol, similar volatile fuels, or combinations thereof. Alcohol, such as ethanol, can be derived from renewable biomass.

[0093] However, according to further embodiments, the internal combustion engine 1 as referred to herein, may be a diesel engine, i.e. a type of compression ignition engine. The internal combustion engine 1 may thus be configured to operate on diesel or a diesel-like fuel, such as biodiesel, biomass to liquid (BTL), or gas to liquid (GTL) diesel. Diesel-like fuels, such as biodiesel, can be obtained from renewable sources such as vegetable oil which mainly comprises fatty acid methyl esters (FAME). Diesel-like fuels can be produced from many types of oils, such as rapeseed oil (rapeseed methyl ester, RME) and soybean oil (soy methyl ester, SME). According to embodiments herein, the internal combustion engine 1 is a four-stroke internal combustion engine 1.

[0094] Moreover, according to some embodiments, the internal combustion engine 1 may be configured to operate on gaseous fuels, such as natural gas, biogas, liquefied petroleum gas (LPG), or hydrogen. A gas-fuelled internal combustion engine may employ either spark ignition or compression ignition with a pilot fuel. Natural gas, which primarily consists ofmethane, can be derived from fossil sources or renewable biogas, which is produced from organic waste through anaerobic digestion.

[0095] According to some embodiments, the internal combustion engine 1 may be a hydrogen internal combustion engine, designed to run on hydrogen as a primary fuel. Hydrogen can be combusted using spark ignition or compression ignition, depending on the engine design. Hydrogen combustion produces no direct carbon dioxide emissions, making it a potential alternative for reducing greenhouse gas emissions from internal combustion engines.

[0096] Hydrogen fuel can be sourced from various production methods, including electrolysis powered by renewable energy.

[0097] Additionally, in some embodiments, the internal combustion engine 1 may be a dual-fuel or multi-fuel engine, capable of operating on a combination of fuels. For example, the engine may be configured to run on a mixture of hydrogen and natural gas, or a blend of diesel and gaseous fuels in a compression ignition setup. Dual-fuel configurations can enhance fuel flexibility, efficiency, and emissions control.

[0098] As schematically depicted in Fig. 2, the engine 1 comprises a crankshaft 4. The crankshaft 4 is positioned within an engine block of the engine 1 and extends along a longitudinal axis of the engine 1. The crankshaft 4 is rotationally supported by main bearings to the engine block. Each of the cylinders c1-c6 houses a piston, which is connected to the crankshaft 4 via a connecting rod. The pistons and connecting rods are not illustrated in Fig. 2 for reasons of brevity and clarity.

[0099] A small end of the connecting rod is pivotally connected to the piston, while a big end is rotatably mounted on an offset section of the crankshaft 4, commonly referred to as a crankpin. As the crankshaft 4 rotates, the crankpin moves along a circular path, causing the connecting rod to convert rotational motion into a reciprocating motion of the piston within the cylinder c1-c6. Moreover, as schematically depicted in Fig. 2, the engine 1 comprises a camshaft assembly 10.

[0100] Fig. 3 schematically illustrates the camshaft assembly 10 of the internal combustion engine 1 illustrated in Fig. 2. Moreover, in Fig. 3, the crankshaft 4 of the engine 1, a control arrangement 21 of the engine 1, and an output unit 51 of the vehicle 2 have been schematically depicted. Below, simultaneous reference is made to Fig. 1 - Fig. 3, if not indicated otherwise.The camshaft assembly 10 of the engine 1 comprises a camshaft 6 and a camshaft bearing assembly 3. According to the illustrated embodiments, the camshaft 6 is rotationally arranged to a cylinder head of the engine 1 via the camshaft bearing assembly 3. According to further embodiments, the camshaft assembly 10 and the camshaft 6 thereof may be arranged at another part of the engine 1. The cylinder head is an assembly of the internal combustion engine 1, located at an upper part of the engine block. The cylinder head houses intake and exhaust ports, and valves v1 , v2, v3, v4, v5, v6 that control the flow of air and fuel into the cylinders c1-c6, as is further explained herein.

[0101] The camshaft bearing assembly 3 comprises a number of camshaft bearings 3’ each rotationally supporting a portion of the camshaft 6. The camshaft 6 comprises a number of cam lobes n1 , n2, n3, n4, n5, n6. The reference signs for the number of cam lobes n1 , n2, n3, n4, n5, n6 are in some places herein abbreviated “n1 - n6” for reasons of brevity and clarity. According to the illustrated embodiments, the camshaft 6 comprises six cam lobes n1 - n6, but may comprise another number of cam lobes n1 - n6, as is further explained herein. Moreover, the camshaft assembly 10 comprises a number of rocker arms a1, a2, a3, a4, a5, a6 and a rocker arm shaft 36, wherein each rocker arm a1, a2, a3, a4, a5, a6 is pivotally mounted on the rocker arm shaft 36. The reference signs for the number of rocker arms a1 , a2, a3, a4, a5, a6 are in some places herein abbreviated “a1 - a6” for reasons of brevity and clarity.

[0102] Each rocker arm a1, a2, a3, a4, a5, a6 comprises a roller r1, r2, r3, r4, r5, r6 rotationally arranged at a first end of the rocker arm a1 , a2, a3, a4, a5, a6, wherein a second end of the rocker arm a1 , a2, a3, a4, a5, a6 is operably connected to a valve v1 , v2, v3, v4, v5, v6 of the engine 1. The roller r1 , r2, r3, r4, r5, r6 of each rocker arm a1 , a2, a3, a4, a5, a6 is in abutting contact with a respective cam lobe n1 , n2, n3, n4, n5, n6, and is arranged to roll against the cam lobe n1, n2, n3, n4, n5, n6 during rotation of the camshaft 6.

[0103] The reference signs for the number of rollers r1 , r2, r3, r4, r5, r6 are in some places herein abbreviated “r1 - r6” for reasons of brevity and clarity. Likewise, the reference signs for the number of valves v1 , v2, v3, v4, v5, v6 are in some places herein abbreviated “v1 - v6” for reasons of brevity and clarity.

[0104] Each cam lobe n1-n6 is eccentrically shaped and configured to actuate the corresponding rocker arm a1-a6 as the camshaft 6 rotates. As a cam lobe n1-n6 rotates, its eccentric profile causes the roller r1-r6 of the corresponding rocker arm a1-a6 to move, thereby pivoting the rocker arm a1-a6 about the rocker arm shaft 36. This pivotal movement of the rocker arm a1-a6 results in the second end of the rocker arm a1-a6 pressing against the corresponding valve v1-v6, thereby opening the valve v1-v6 at a predetermined timing relative to the rotation of the camshaft 6.

[0105] The camshaft assembly 10 further comprises a number of valve springs, each associated with a corresponding valve v1-v6. The valve springs have not been illustrated in Fig. 3 for reasons of brevity and clarity. The valve springs are configured to exert a biasing force that returns the respective valve v1-v6 to its closed position once the corresponding cam lobe nine rotates past the highest lift point. The valve springs further ensure that the rollers r1-r6 of the rocker arms a1-a6 remain in contact with the corresponding cam lobes n1-n6 during rotation of the camshaft 6. Each valve v1-v6 is slidably arranged in a valve guide, which is integrated into the cylinder head and ensures precise alignment of the valve movement.

[0106] The valves v1-v6 illustrated in Fig. 3 may be intake valves or exhaust valves of the engine 1. The engine 1 may comprise a second camshaft assembly comprising the corresponding components as the camshaft assembly 10 explained herein. In embodiments in which the camshaft assembly 10 is arranged to control the opening and closing of intake valves of the engine 1 , the second camshaft assembly may be arranged to control the opening and closing of exhaust valves of the engine 1. Similarly, in embodiments in which the camshaft assembly 10 is arranged to control the opening and closing of exhaust valves of the engine 1 , the second camshaft assembly may be arranged to control the opening and closing of intake valves of the engine 1.

[0107] In the schematic representation of Fig. 3, each rocker arm a1-a6 is depicted as operably connected to one valve v1-v6. However, according to further embodiments, each rocker arm a1-a6 may be operably connected to two or more valves and may be arranged to control the opening and closing events of these two or more valves. The camshaft assembly 10 may further comprise a valve cover (not shown) that encloses the camshaft 6, rocker arms a1-a6, and associated components, providing protection and preventing oil leakage.

[0108] The camshaft assembly 10 further comprises a hydraulic cam phase shifting arrangement 5. As is further explained herein, the camshaft 6 is rotationally coupled to the crankshaft 4 of the engine 1 via the hydraulic cam phase shifting arrangement 5. In more detail, the hydraulic cam phase shifting arrangement 5 is coupled to a drive member 24. The drive member 24 is also schematically illustrated in Fig. 2. The drive member 24 is rotationally linked to the crankshaft 4 via a camshaft drive arrangement 34. In other words, the drivemember 24 is arranged to co-rotate with the crankshaft 4. The camshaft drive arrangement 34 may comprise a chain, a belt, or a set of meshed gears.

[0109] As is further explained herein, the hydraulic cam phase shifting arrangement 5 is controllable to adjust a phase angle of the camshaft 6 relative to the crankshaft 4.

[0110] Fig. 4 schematically illustrates a cross-section of the hydraulic cam phase shifting arrangement 5 of the camshaft assembly 10 illustrated in Fig. 3. Below, simultaneous reference is made to Fig. 1 - Fig. 4, if not indicated otherwise.

[0111] The hydraulic cam phase shifting arrangement 5 comprises a first member 14 and a second member 16. The first member 14 is rigidly attached to the drive member 24 and the second member 16 is rigidly attached to the camshaft 6. The first member 14 may also be referred to as a driven member and the second member 16 may also be referred to as a camshaft member. The first member 14 comprises a number of inwardly protruding elements and the second member 16 comprises a number of outwardly protruding elements. The inwardly protruding elements and the outwardly protruding elements have not been provided with reference signs in Fig. 4 for reasons of brevity and clarity.

[0112] A first set of hydraulic chambers A and a second set of hydraulic chambers B are formed between the inwardly protruding elements of the first member 14 and the outwardly protruding elements of the second member 16. The camshaft assembly 10 further comprises a hydraulic control unit 31 controllable to adjust the amount of hydraulic fluid in the first and second sets of hydraulic chambers A, B so as to adjust the phase angle of the camshaft 6 relative to the crankshaft 4.

[0113] The hydraulic control unit 31 may comprise one or more solenoid valves configured to regulate the flow of hydraulic fluid to and from the first and second sets of hydraulic chambers A, B. These solenoid valves may be electronically controlled based on operational parameters of the engine 1, such as engine speed, load conditions, and temperature.

[0114] The hydraulic control unit 31 may further comprise a hydraulic pump arranged to supply pressurized hydraulic fluid to the first and second sets of hydraulic chambers A, B. The hydraulic pump may be mechanically driven by the engine 1 or electrically operated.

[0115] Additionally, the hydraulic control unit 31 may include one or more pressure sensors configured to monitor the pressure levels within the hydraulic chambers A, B. These pressuresensors may be configured to provide feedback to a control system of the engine 1 to support the regulation of the hydraulic cam phase shifting arrangement 5, for example, by monitoring pressure levels to ensure proper operating conditions.

[0116] The hydraulic control unit 31 may also comprise a fluid reservoir for storing hydraulic fluid. The fluid reservoir may be connected to a network of fluid passages that distribute hydraulic fluid between the pump, the solenoid valves, and the first and second sets of hydraulic chambers A, B.

[0117] The hydraulic fluid supplied to the first and second sets of hydraulic chambers A, B may be engine oil sourced from a lubrication system of the engine 1 , or a separate hydraulic fluid circuit. In some embodiments, using engine oil can simplify the overall design by utilizing the existing oil supply of the engine 1. In other embodiments, the hydraulic control unit 31 may operate using a dedicated hydraulic fluid that is separate from the engine oil circuit. This separate hydraulic system may include an independent fluid reservoir, pump, and filtration system, allowing for optimized fluid properties tailored to the operation of the hydraulic cam phase shifting arrangement 5.

[0118] Moreover, the hydraulic control unit 31 may include one or more check valves or flow restrictors configured to control the rate of fluid transfer between the hydraulic chambers A, B, thereby influencing the speed and stability of the phase adjustment process. In some embodiments, the hydraulic control unit 31 may further comprise a thermal management system, such as a heat exchanger or cooling circuit, arranged to regulate the temperature of the hydraulic fluid to ensure consistent performance and prevent overheating.

[0119] The control arrangement 21 of the engine 1 is operably connected to the hydraulic control unit 31. The control arrangement 21 may comprise an electronic control unit configured to regulate the operation of the hydraulic cam phase shifting arrangement 5 based on various engine operating parameters. It may include a microcontroller or processor that executes control algorithms to determine an appropriate phase angle adjustment of the camshaft 6 relative to the crankshaft 4.

[0120] To achieve this, the control arrangement 21 may receive input signals from sensors monitoring operating conditions such as engine speed, load, fluid temperature, throttle position, and manifold pressure. By processing these signals, the control arrangement 21 can generate control signals for one or more solenoid valves within the hydraulic control unit 31. In response, the hydraulic fluid supply to the first and second sets of hydraulic chambersA, B is adjusted, enabling real-time phase adjustment of the camshaft 6. This allows for optimized combustion timing, improved efficiency, and reduced emissions.

[0121] The control arrangement 21 may be integrated into an engine control module (ECM) that governs multiple engine functions, including fuel injection and ignition timing. Alternatively, it may be a standalone unit dedicated to controlling the hydraulic cam phase shifting arrangement 5. In some embodiments, the control arrangement 21 may be configured to communicate with other vehicle systems via a data bus, such as a Controller Area Network (CAN bus), allowing coordination with other powertrain control functions. It may also store calibration data or employ adaptive learning algorithms to refine camshaft phase adjustments over time based on engine performance history.

[0122] In Fig. 4, the second member 16 is illustrated at a mid-position within its angular range relative to the first member 14.

[0123] Fig. 5 illustrates the cross-section of the hydraulic cam phase shifting arrangement 5 illustrated in Fig. 4, in which the hydraulic cam phase shifting arrangement 5 has advanced the phase angle of the camshaft 6 relative to the crankshaft 4.

[0124] The control arrangement 21 has transmitted a control signal to the hydraulic control unit 31 to advance the phase angle of the camshaft 6 relative to the crankshaft 4. In response, the hydraulic control unit 31 has actuated one or more solenoid valves to transfer hydraulic fluid from the first set of hydraulic chambers A to the second set of hydraulic chambers B. As a result, the pressure in the first set of hydraulic chambers A has decreased, while the pressure in the second set of hydraulic chambers B has increased.

[0125] This pressure change has caused the second member 16 to rotate relative to the first member 14 in the advancing direction. In Fig. 5, this phase shift is illustrated by a reduced volume of the first set of hydraulic chambers A and an increased volume of the second set of hydraulic chambers B.

[0126] By advancing the camshaft phase, the intake and exhaust valve events occur earlier in the engine cycle relative to the movement of the pistons within the cylinders c1-c6. Advancing the intake valve timing allows the intake valves to open and close earlier, which can improve cylinder filling at higher engine speeds. Similarly, advancing the exhaust valve timing results in earlier opening and closing of the exhaust valves, which can enhance exhaust gasscavenging. These adjustments can improve engine performance by optimizing combustion timing, increasing volumetric efficiency, and enhancing fuel-air mixing.

[0127] Fig. 6 illustrates the cross-section of the hydraulic cam phase shifting arrangement 5 illustrated in Fig. 5, in which the hydraulic cam phase shifting arrangement 5 has retarded the phase angle of the camshaft 6 relative to the crankshaft 4.

[0128] Similarly, the control arrangement 21 has transmitted a control signal to the hydraulic control unit 31 to retard the phase angle of the camshaft 6 relative to the crankshaft 4. In response, the hydraulic control unit 31 has actuated one or more solenoid valves to transfer hydraulic fluid from the second set of hydraulic chambers B to the first set of hydraulic chambers A. As a result, the pressure in the second set of hydraulic chambers B has decreased, while the pressure in the first set of hydraulic chambers A has increased.

[0129] This pressure change has caused the second member 16 to rotate relative to the first member 14 in the retarding direction. In Fig. 6, this phase shift is illustrated by an increased volume of the first set of hydraulic chambers A and a reduced volume of the second set of hydraulic chambers B.

[0130] By retarding the camshaft phase, the intake and exhaust valve events occur later in the engine cycle relative to the movement of the pistons within the cylinders c1-c6. Retarding the intake valve timing allows the intake valves to open and close later, which can improve combustion stability and reduce pumping losses at lower engine speeds. Similarly, retarding the exhaust valve timing results in later opening and closing of the exhaust valves, which can enhance exhaust heat retention and improve emissions performance. These adjustments can improve engine efficiency under certain operating conditions by optimizing combustion timing, reducing fuel consumption, and improving emission control.

[0131] Fig. 7 illustrates first a graph showing a crankshaft torque Tc as a function of time t during rotation of the crankshaft 4. Below, simultaneous reference is made to Fig. 1 - Fig. 7, if not indicated otherwise.

[0132] The crankshaft torque Tc is representative of the torque needed for rotating the crankshaft 4, and is thereby also representative of the torque between the first and second members 14, 16 of the hydraulic cam phase shifting arrangement 5 during operation of the engine 1.The hydraulic control unit 31 utilizes the crankshaft torque Tc for transferring hydraulic fluid between the first set of hydraulic chambers A and the second set of hydraulic chambers B. As illustrated in Fig. 7, the graph represents the crankshaft torque Tc as a function of time t during the rotation of the crankshaft 4. The horizontal line in Fig. 7 indicates zero torque, meaning that at points where the graph crosses this line, no net torque is exerted between the first member 14 and the second member 16 of the hydraulic cam phase shifting arrangement 5.

[0133] The torque Tc varies periodically between positive and negative values, which is a result of the interaction between the cam lobes n1-n6, the rollers r1-r6, and the rocker arms a1-a6 of the camshaft assembly 10. As the camshaft 6 rotates, the cam lobes n1-n6 engage with the rollers r1-r6, which are in contact with the rocker arms a1-a6. This engagement generates forces that act against the restoring force of the valve springs, causing the rocker arms a1-a6 to pivot about the rocker arm shaft 36 and press the valves v1-v6 to their open positions.

[0134] During the opening phase of the valves v1-v6, the cam lobes n1-n6 push against the rollers r1-r6, transferring force through the rocker arms a1-a6 to move the valves v1-v6 from their closed positions. This action increases resistance in the camshaft assembly 10, requiring additional torque from the crankshaft 4 to sustain rotation of the camshaft 6, which corresponds to the positive peaks in Fig. 7.

[0135] Conversely, during the closing phase, the cam lobes n1-n6 rotate past their peak lift points, allowing the valve springs to return the valves v1-v6 to their closed positions. As the valves close, the stored energy in the valve springs assists in driving the camshaft 6 forward, temporarily reducing the torque required to rotate the crankshaft 4, resulting in the negative peaks in Fig. 7.

[0136] The hydraulic control unit 31 takes advantage of this cyclic variation in torque Tc to obtain the transfer of hydraulic fluid between the first and second sets of hydraulic chambers A, B. This reduces the energy required for phase adjustment while ensuring smooth and precise control of the camshaft phase angle.

[0137] As seen in Fig. 3, the camshaft assembly 10 comprises a pulse wheel 26 and a first sensor s1. The pulse wheel 26 is rotationally coupled to the camshaft 6 and co-rotates with the camshaft 6. The first sensor s1 is configured to monitor the rotation and angular position of the pulse wheel 26. The first sensor s1 may also be referred to as a camshaft position sensor and is configured to provide real-time data regarding the rotational speed and angularposition of the camshaft 6. The pulse wheel 26 may be a toothed wheel, slotted disc, or magnetic ring, depending on the detection method of the first sensor s1. The pulse wheel 26 may be designed to generate a periodic signal corresponding to the rotational movement of the camshaft 6. The first sensor s1 may operate based on magnetic, optical, or Hall-effect principles, allowing it to detect the passage of teeth, slots, or magnetic markers on the pulse wheel 26.

[0138] Moreover, as schematically indicated in Fig. 3, the engine 1 comprises a second sensor s2, wherein the second sensor s2 is arranged to monitor rotation and rotational position of the crankshaft 4 of the engine 1. The second sensor s2 may also be referred to as a crankshaft position sensor and is configured to provide real-time data regarding the rotational speed and angular position of the crankshaft 4. The second sensor s2 may operate based on magnetic, optical, or Hall-effect principles, detecting features on a reference element, such as a toothed wheel or magnetic ring, that is rotationally coupled to the crankshaft 4.

[0139] According to embodiments herein, the control arrangement 21 is configured to monitor the phase angle, including the rate of change of the phase angle, based on data received from the first and second sensors s1 , s2. The signals from the first sensor s1 and the second sensor s2 enable precise determination of the relative phase angle between the camshaft 6 and the crankshaft 4. However, according to further embodiments, the control arrangement 21 may be configured to monitor the phase angle, including the rate of change of the phase angle, based on signals from one or more other types of sensors or estimated values derived from engine operating parameters. Moreover, according to embodiments herein, the control arrangement 21 is configured to diagnose an operational performance of the camshaft bearing assembly 3 based on the monitored rate of change of the phase angle. By diagnosing the operational performance of the camshaft bearing assembly 3 based on the monitored rate of change of the phase angle, the control arrangement 21 can enable early detection of malfunctions in the camshaft bearing assembly 3.

[0140] Fig. 8 illustrates second a graph showing a crankshaft torque Tc as a function of time t during rotation of the crankshaft 4. Below, simultaneous reference is made to Fig. 1 - Fig. 8, if not indicated otherwise.

[0141] In comparison to Fig. 7, the entire torque curve in Fig. 8 is shifted to a higher level, meaning that the crankshaft torque Tc remains increased throughout the rotation of the crankshaft 4. This condition may occur if the camshaft bearing assembly 3 is worn or malfunctioning, leading to increased friction or resistance in the rotational movement of the camshaft 6relative to the cylinder head of the engine 1. The increased crankshaft torque Tc directly influences the operation of the hydraulic cam phase shifting arrangement 5 by affecting the rate of change of the phase angle when the hydraulic cam phase shifting arrangement 5 is adjusting the phase angle.

[0142] Thus, by diagnosing the operational performance of the camshaft bearing assembly 3 based on the monitored rate of change of the phase angle, the control arrangement 21 can detect malfunctions in the camshaft bearing assembly 3 at an early stage.

[0143] According to some embodiments, the control arrangement 21 is configured to monitor the retarding rate of the phase angle when the hydraulic cam phase shifting arrangement 5 is retarding the phase angle. According to these embodiments, the control arrangement 21 may be configured to set a fault indicator of the hydraulic cam phase shifting arrangement 5 if the monitored retarding rate exceeds a first threshold.

[0144] When the hydraulic cam phase shifting arrangement 5 is retarding the phase angle of the camshaft 6 relative to the crankshaft 4, the increase in crankshaft torque Tc results in a higher resistance to the backward rotation of the second member 16 relative to the first member 14. As a consequence, the hydraulic fluid transfer from the second set of hydraulic chambers B to the first set of hydraulic chambers A occurs more rapidly due to the increased pressure difference across the chambers A, B. This effect increases the retarding rate of the phase angle, meaning that the camshaft phase is adjusted towards a later timing more quickly than in the normal condition illustrated in Fig. 7.

[0145] Thus, by setting a fault indicator of the hydraulic cam phase shifting arrangement 5 if the monitored retarding rate exceeds the first threshold, the fault indicator can be set at instances in which the friction provided by the camshaft bearing assembly 3 has increased, which is an early indication of an upcoming malfunction of the camshaft bearing assembly 3. Accordingly, in this manner, a control arrangement 21 is provided having improved conditions for early detection of malfunctions in the camshaft bearing assembly 3.

[0146] Moreover, according to some embodiments, the control arrangement 21 may be configured to monitor the advancing rate of the phase angle when the hydraulic cam phase shifting arrangement 5 is advancing the phase angle. According to these embodiments, the control arrangement 21 may be configured to set a fault indicator of the hydraulic cam phase shifting arrangement 5 if the monitored advancing rate is below a second threshold.When the hydraulic cam phase shifting arrangement 5 is advancing the phase angle of the camshaft 6 relative to the crankshaft 4, the increased crankshaft torque Tc acts against the forward rotational movement of the second member 16 relative to the first member 14. This increased resistance leads to a reduction in the pressure differential driving the hydraulic fluid from the first set of hydraulic chambers A to the second set of hydraulic chambers B, thereby slowing down the fluid transfer. As a result, the advancing rate of the phase angle is reduced, meaning that the camshaft phase is adjusted towards an earlier timing at a slower rate compared to the normal condition shown in Fig. 7.

[0147] Thus, by setting a fault indicator of the hydraulic cam phase shifting arrangement 5 if the monitored advancing rate is below a second threshold, the fault indicator can be set at instances in which the friction provided by the camshaft bearing assembly 3 has increased, which is an early indication of an upcoming malfunction of the camshaft bearing assembly 3. Accordingly, in this manner, a control arrangement 21 is provided having improved conditions for early detection of malfunctions in the camshaft bearing assembly 3.

[0148] Furthermore, according to some embodiments, the control arrangement 21 is configured to monitor the retarding rate of the phase angle when the hydraulic cam phase shifting arrangement 5 is retarding the phase angle, and monitor the advancing rate of the phase angle when the hydraulic cam phase shifting arrangement 5 is advancing the phase angle. According to these embodiments, the control arrangement 21 may be configured to set a fault indicator of the hydraulic cam phase shifting arrangement 5 based on the difference between the monitored retarding rate and the monitored advancing rate. In more detail, according to these embodiments, the control arrangement 21 may be configured to set the fault indicator of the hydraulic cam phase shifting arrangement 5 if the difference between the monitored retarding rate and the monitored advancing rate exceeds a threshold difference. As understood from the above, an increase of the difference between the monitored retarding rate and the monitored advancing rate clearly indicates an increased resistive torque provided by the camshaft bearing assembly 3 due to friction.

[0149] Thus, by setting the fault indicator if the difference between the monitored retarding rate and the monitored advancing rate exceeds the threshold difference, the fault indicator can be accurately set at instances in which the friction provided by the camshaft bearing assembly 3 has increased, which is an early indication of an upcoming malfunction of the camshaft bearing assembly 3. Accordingly, in this manner, a control arrangement 21 is provided having improved conditions for early detection of malfunctions in the camshaft bearing assembly 3. In addition, the control arrangement 21 can more reliably distinguish problemsrelated to the camshaft bearing assembly 3 from other types of faults, such as faults in the hydraulic cam phase shifting arrangement 5. Thus, in this manner, the control arrangement 21 enhances diagnostic accuracy by identifying deviations in phase shifting behaviour that are indicative of issues specific to the camshaft bearing assembly 3. This can help prevent misinterpretation of faults and support more effective troubleshooting, potentially reducing unnecessary maintenance actions and component replacements.

[0150] A fault indicator, as referred to herein, may be represented by a specific error code that may convey information about the type and location of the fault. The fault indicator could take various forms, such as numeric, alphanumeric, symbolic, and / or encoded data formats. Moreover, the fault indicator could contain data about the affected component, fault severity, and possibly also the time of detection.

[0151] The feature “set / setting a fault indicator,” as used herein, may refer to generating, storing, and / or transmitting a fault indicator. Setting a fault indicator may involve updating a memory, such as a memory within the control arrangement 21 , activating a diagnostic trouble code, or triggering a communication signal to an external system. As can be seen in Fig. 3, according to the illustrated embodiments, the control arrangement 21 is operably connected to the output unit 51, which, as depicted in Fig. 1, is arranged in the occupant compartment 55 of the vehicle 2. The output unit 51 may comprise a display, indicator lights, and / or an auditory alert system for conveying fault-related information. It may be integrated into an instrument cluster, a central display, or a standalone diagnostic interface. The control arrangement 21 may be configured to output fault indicators via the output unit 51 , enabling real-time fault notification.

[0152] In some embodiments, the output unit 51 may be configured to present fault indicators as error codes, warning messages, or graphical symbols. As an alternative, or in addition, the output unit 51 may generate audible alerts, such as beeps or chimes, to notify the operator of fault indicators. Moreover, setting a fault indicator may initiate further actions, such as limiting certain engine functions and / or vehicle functions.

[0153] Furthermore, the output unit 51 may support wireless communication, wired connections, or other data interfaces, enabling the control arrangement 21 to transmit fault indicators to external systems for remote diagnostics, fleet management, or maintenance scheduling.

[0154] Fig. 9 schematically illustrates a method 100 of diagnosing a camshaft bearing assembly of an internal combustion engine. The internal combustion engine may be an internalcombustion engine 1 according to the embodiments explained with reference to Fig. 1 - Fig.

[0155] 8. Therefore, below, simultaneous reference is made to Fig. 1 - Fig. 9, if not indicated otherwise.

[0156] The method is a method 100 of diagnosing a camshaft bearing assembly 3 of an internal combustion engine 1, wherein the method 100 is performed by a control arrangement 21, and wherein the engine 1 comprises a crankshaft 4, a hydraulic cam phase shifting arrangement 5, and a camshaft 6 rotationally arranged via the camshaft bearing assembly 3 and rotationally coupled to the crankshaft 4 via the hydraulic cam phase shifting arrangement 5. The hydraulic cam phase shifting arrangement 5 is controllable to adjust a phase angle of the camshaft 6 relative to the crankshaft 4. The method 100 comprises the steps of:

[0157] - monitoring 110 the rate of change of the phase angle when the hydraulic cam phase shifting arrangement 5 is adjusting the phase angle, and

[0158] - diagnosing 120 an operational performance of the camshaft bearing assembly 3 based on the monitored rate of change of the phase angle.

[0159] According to some embodiments, the method 100 comprises:

[0160] - monitoring 111 the retarding rate of the phase angle when the hydraulic cam phase shifting arrangement 5 is retarding the phase angle, and

[0161] wherein the step of diagnosing 120 the operational performance of the camshaft bearing assembly 3 comprises:

[0162] - setting 121 a fault indicator of the hydraulic cam phase shifting arrangement 5 if the monitored retarding rate exceeds a first threshold.

[0163] Moreover, according to some embodiments, the method 100 comprises:

[0164] - monitoring 112 the advancing rate of the phase angle when the hydraulic cam phase shifting arrangement 5 is advancing the phase angle, and

[0165] wherein the step of diagnosing 120 the operational performance of the camshaft bearing assembly 3 comprises:

[0166] - setting 122 a fault indicator of the hydraulic cam phase shifting arrangement 5 if the monitored advancing rate is below a second threshold.

[0167] Furthermore, according to some embodiments, the method 100 comprises:

[0168] - monitoring 111 the retarding rate of the phase angle when the hydraulic cam phase shifting arrangement 5 is retarding the phase angle, and

[0169] - monitoring 112 the advancing rate of the phase angle when the hydraulic cam phase shifting arrangement 5 is advancing the phase angle,wherein the step of diagnosing 120 the operational performance of the camshaft bearing assembly 3 comprises:

[0170] - setting 123 a fault indicator of the hydraulic cam phase shifting arrangement 5 based on the difference between the monitored retarding rate and the monitored advancing rate.

[0171] According to some embodiments, the step of setting 123 the fault indicator comprises:

[0172] - setting 124 a fault indicator of the hydraulic cam phase shifting arrangement 5 if the difference between the monitored retarding rate and the monitored advancing rate exceeds a threshold difference.

[0173] It will be appreciated that the various embodiments described for the method 100 are all combinable with the control arrangement 21 as described herein. That is, the control arrangement 21 may be configured to perform any one of the method steps 110, 111, 112, 120, 121, 122, 123, and 124.

[0174] Fig. 10 illustrates a computer-readable medium 200 comprising instructions which, when executed by a computer, cause the computer to carry out the method 100 according to some embodiments of the present disclosure. According to some embodiments, the computer-readable medium 200 comprises 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 some embodiments. The computer may be comprised in the control arrangement 21.

[0175] One skilled in the art will appreciate that the method 100 of diagnosing a camshaft bearing assembly 3 of an internal combustion engine 1 may be implemented by programmed instructions. These programmed instructions are typically constituted by a computer program, which, when it is executed in the control arrangement 21 ensures that the control arrangement 21 carries out the desired control, such as the method steps 110, 111, 112, 120, 121, 122, 123, and 124 described herein. The computer program is usually part of a computer program product which comprises a suitable digital storage medium on which the computer program is stored, such as the computer-readable medium 200 illustrated in Fig.

[0176] 10. In other words, the computer program product may be a computer readable medium 200 and the computer program may be stored in the computer readable medium 200.

[0177] The control arrangement 21 may comprise a computer which may take the form of substantially any suitable type of hardware or hardware / firmware device implemented using processing circuity such as, but not limited to, a processor, Central Processing Unit (CPU), acontroller, an arithmetic logic unit (ALU), a digital signal processor, an Application Specific Integrated Circuit (ASIC), a circuit for digital signal processing (digital signal processor, DSP), a microcomputer, a field programmable gate array (FPGA), a System-on-Chip (SoC), a programmable logic unit, a microprocessor, or any other device capable of electronically performing operations in a defined manner, or other processing logic that may interpret and execute instructions. The herein utilised expression “computer” may represent a processing circuitry comprising a plurality of processing circuits, such as, e.g., any, some or all of the ones mentioned above.

[0178] The control arrangement 21 may further comprise a memory unit, wherein the computer may be connected to the memory unit, which may provide the computer with, for example, stored program code and / or stored data which the computer may need to enable it to do calculations. The computer may also be adapted to store partial or final results of calculations in the memory unit. The memory unit may comprise a physical device utilised to store data or programs, i.e., 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 may comprise e.g. a memory card, a flash memory, a USB memory, a hard disc, or another similar volatile or non-volatile storage unit for storing data such as e.g. ROM (Read-Only Memory), PROM (Programmable Read-Only Memory), EPROM (Erasable PROM), EEPROM (Electrically Erasable PROM), etc. in different embodiments.

[0179] The control arrangement 21 is connected to components of the vehicle 2 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 to signals processable by the control arrangement 21. These signals may then be supplied to the computer. One or more output signal sending devices may be arranged to convert calculation results from the computer to output signals for conveying to other parts of the vehicle's control system and / or the component or components for which the signals are intended. Each of the connections to the respective components of the vehicle 2 for receiving and sending input and output signals may take the form of one or more from among a cable, a data bus, e.g. a CAN (controller area network) bus, a MOST (media orientated systems transport) bus or some other bus configuration, or a wireless connection.In the embodiments illustrated, the vehicle 2 comprises a control arrangement 21 but might alternatively be implemented wholly or partly in two or more control arrangements, two or more control systems, or two or more control units.

[0180] Control systems in modern vehicles generally comprise a communication bus system consisting of one or more communication buses for connecting a number of electronic control units (ECUs), or controllers, to various components on board the vehicle. Such a control system may comprise a large number of control units and taking care of a specific function may be shared between two or more of them. Vehicles and engines of the type here concerned are therefore often provided with significantly more control arrangements than depicted in Fig. 3 - Fig. 6, as one skilled in the art will surely appreciate.

[0181] The computer-readable medium 200 may be provided for instance in the form of a data carrier carrying computer program code for performing at least some of the method steps 110, 111, 112, 120, 121, 122, 123, and 124 according to some embodiments of the method 100 when being loaded into one or more computers of the control arrangement 21. The data carrier may be, e.g. a CD ROM disc, as is illustrated in Fig. 10, or a ROM (read-only memory), a PROM (programable read-only memory), an EPROM (erasable PROM), a flash memory, an EEPROM (electrically erasable PROM), a hard disc, a memory stick, an optical storage device, a magnetic storage device or any other appropriate medium such as a disk or tape that may hold machine readable data in a non-transitory manner. Accordingly, in some embodiments, the computer-readable medium 200 may be a non-transitory computer-readable medium, such as a tangible electronic, magnetic, optical, infrared, electromagnetic, and / or semiconductor system, apparatus, and / or device. The computer-readable medium 200 may furthermore be provided as computer program code on a server and may be downloaded to the control arrangement 21 remotely, e.g., over an Internet or an intranet connection, or via other wired or wireless communication systems.

[0182] It is to be understood that the foregoing is illustrative of various example embodiments and that the invention is defined only by the appended independent claims. A person skilled in the art will realize that the example embodiments may be modified, and that different features of the example embodiments may be combined to create embodiments other than those described herein, without departing from the scope of the present invention, as defined by the appended independent claims.

[0183] As used herein, the term "comprising" or "comprises" is open-ended, and includes one or more stated features, elements, steps, components, or functions but does not preclude thepresence or addition of one or more other features, elements, steps, components, functions, or groups thereof.

Claims

CLAIMS1. A method (100) of diagnosing a camshaft bearing assembly (3) of an internal combustion engine (1), wherein the method (100) is performed by a control arrangement (21), and wherein the engine (1) comprises:a crankshaft (4),a hydraulic cam phase shifting arrangement (5), anda camshaft (6) rotationally arranged via the camshaft bearing assembly (3) and rotationally coupled to the crankshaft (4) via the hydraulic cam phase shifting arrangement (5),wherein the hydraulic cam phase shifting arrangement (5) is controllable to adjust a phase angle of the camshaft (6) relative to the crankshaft (4),and wherein the method (100) comprises the steps of:monitoring (110) the rate of change of the phase angle when the hydraulic cam phase shifting arrangement (5) is adjusting the phase angle, anddiagnosing (120) an operational performance of the camshaft bearing assembly (3) based on the monitored rate of change of the phase angle.

2. The method (100) according to claim 1, wherein the method (100) comprises:monitoring (111) the retarding rate of the phase angle when the hydraulic cam phase shifting arrangement (5) is retarding the phase angle, andwherein the step of diagnosing (120) the operational performance of the camshaft bearing assembly (3) comprises:setting (121 ) a fault indicator of the hydraulic cam phase shifting arrangement (5) if the monitored retarding rate exceeds a first threshold.

3. The method (100) according to claim 1 or 2, wherein the method (100) comprises:monitoring (112) the advancing rate of the phase angle when the hydraulic cam phase shifting arrangement (5) is advancing the phase angle, andwherein the step of diagnosing (120) the operational performance of the camshaft bearing assembly (3) comprises:setting (122) a fault indicator of the hydraulic cam phase shifting arrangement (5) if the monitored advancing rate is below a second threshold.

4. The method (100) according to any one of the preceding claims, wherein the method (100) comprises:monitoring (111) the retarding rate of the phase angle when the hydraulic cam phase shifting arrangement (5) is retarding the phase angle, andmonitoring (112) the advancing rate of the phase angle when the hydraulic cam phase shifting arrangement (5) is advancing the phase angle,wherein the step of diagnosing (120) the operational performance of the camshaft bearing assembly (3) comprises:setting (123) a fault indicator of the hydraulic cam phase shifting arrangement (5) based on the difference between the monitored retarding rate and the monitored advancing rate.

5. The method (100) according to claim 4, wherein the step of setting (123) the fault indicator comprises:setting (124) a fault indicator of the hydraulic cam phase shifting arrangement (5) if the difference between the monitored retarding rate and the monitored advancing rate exceeds a threshold difference.

6. A computer program comprising instructions which, when the program is executed by a control arrangement (21) of an internal combustion engine (1), cause the control arrangement (21) to carry out the method (100) according to any one of the claims 1 - 5.

7. A computer-readable medium (200) comprising instructions which, when executed by a control arrangement (21) of an internal combustion engine (1), cause the control arrangement (21) to carry out the method (100) according to any one of the claims 1 - 5.

8. A control arrangement (21 ) for an internal combustion engine (1 ), wherein the engine (1 ) comprises:a crankshaft (4),a hydraulic cam phase shifting arrangement (5),a camshaft bearing assembly (3), anda camshaft (6) rotationally arranged via the camshaft bearing assembly (3) and rotationally coupled to the crankshaft (4) via the hydraulic cam phase shifting arrangement (5),wherein the hydraulic cam phase shifting arrangement (5) is controllable to adjust a phase angle of the camshaft (6) relative to the crankshaft (4),wherein the control arrangement (21) is configured to:monitor the rate of change of the phase angle when the hydraulic cam phase shifting arrangement (5) is adjusting the phase angle, anddiagnose an operational performance of the camshaft bearing assembly (3) based on the monitored rate of change of the phase angle.

9. An internal combustion engine (1) comprising:a crankshaft (4),a hydraulic cam phase shifting arrangement (5),a camshaft bearing assembly (3), and- a camshaft (6) rotationally arranged via the camshaft bearing assembly (3) and rotationally coupled to the crankshaft (4) via the hydraulic cam phase shifting arrangement (5),wherein the hydraulic cam phase shifting arrangement (5) is controllable to adjust a phase angle of the camshaft (6) relative to the crankshaft (4),and wherein the internal combustion engine (1) comprises a control arrangement (21) according to claim 8.

10. A vehicle (2) comprising an internal combustion engine (1) according to claim 9.

11. The vehicle (2) according to claim 10, wherein the vehicle (2) is a heavy wheeledvehicle.

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