WO2019151928A1

WO2019151928A1 - Compression release brake arrangement, method of controlling a compression release brake arrangement, and related devices

Info

Publication number: WO2019151928A1
Application number: PCT/SE2019/050064
Authority: WO
Inventors: Hans KARLKVIST; Joakim SOMMANSSON
Original assignee: Scania Cv Ab
Priority date: 2018-01-30
Filing date: 2019-01-29
Publication date: 2019-08-08
Also published as: SE1850106A1

Abstract

A compression release brake arrangement (1) for an engine (3) is disclosed. The arrangement (1) comprises a valve actuator assembly (5) configured to, when activated, perform compression release braking of at least a first cylinder (7') of the engine (3), and a hydraulic arrangement (8) comprising a conduit arrangement (9), and a first and a second 5 actuator valve (11, 12) arranged in the conduit arrangement (9). The hydraulic arrangement (8) is arranged such that the valve actuator assembly is activated (5) when the first and second actuator valves (11, 12) are in an open state, and deactivated when at least one of the first and the second actuator valves (11, 12) is in a closed state. The present disclosure further relates to an engine (3), a vehicle (25), a method (100), a computer program, a computer-readable medium (200), and a control arrangement (5).

Description

Compression Release Brake Arrangement, Method of Controlling a Compression Release Brake Arrangement, and Related Devices

TECHNICAL FIELD

The present disclosure relates to a compression release brake arrangement for an engine. The present disclosure further relates to an engine comprising a compression release brake arrangement, a vehicle comprising an engine, a method of controlling a compression release brake arrangement, a computer program, a computer-readable medium, and a control arrangement for a compression release brake arrangement.

BACKGROUND

Internal combustion engines, such as four-stroke internal combustion engines, comprise one or more cylinders and a piston arranged 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 usually further comprises one or more inlet valves and outlet valves as well as one or more fuel supply arrangements. The one or more inlet valves and outlet valves are controlled by a respective valve control arrangement usually comprising one or more camshafts rotatably connected to a crankshaft of the engine, via a belt, chain, gears, or similar. A four-stroke internal combustion engine completes four separate strokes while turning a crankshaft. A stroke refers to the full travel of the piston along the cylinder, in either direction. The uppermost position of the piston in the cylinder is usually referred to as the top dead centre TDC, and the lowermost position of the piston in the cylinder is usually referred to as the bottom dead centre BDC.

The strokes are completed in the following order, inlet stroke, compression stroke, expansion stroke and exhaust stroke. During operation of a conventional four-stroke internal combustion engine, the inlet valve control arrangement controls inlet valves of a cylinder to an open state during the inlet stroke of a piston within the cylinder, to allow air, or a mixture of air and fuel, to enter the cylinder. During the compression stroke, all valves should be closed to allow compression of the air, or the mixture of the air and fuel, in the cylinder. If the engine is in a power producing state, fuel in the cylinder is ignited, usually towards the end of the compression stroke, for example by a spark plug or by compression heat in the cylinder. The combustion of fuel within the cylinder significantly increases pressure and temperature in the cylinder. The combustion of the fuel usually continues into a significant portion of the subsequent expansion stroke. The increased pressure and temperature in the cylinder obtained by the combustion is partially converted into mechanical work supplied to the crank shaft during the expansion stroke. Obviously, all valves should remain closed during the expansion stroke to allow the increased pressure and temperature to be converted into mechanical work. The expansion stroke is also usually referred to as the combustion stroke, since usually, the majority of the combustion takes place during the expansion stroke. In the subsequent exhaust stroke, the exhaust valve control arrangement controls exhaust valves of the cylinder to an open state to allow exhaust gases to be expelled out of the cylinder into an exhaust system.

During normal engine braking, occurring for example when a driver of a vehicle releases an accelerator pedal, the engine will continue to operate in the above described strokes, with the exception that, normally, no fuel is supplied to the engine during engine braking, and consequently, no combustion will take place during the end of the compression stroke or during the expansion stroke. In this condition, the engine will provide some braking torque due to internal friction and due to the pumping of air from the inlet to the exhaust, in the respective inlet stroke and exhaust stroke. As a piston travels upward during its compression stroke, the gases that are trapped in the cylinder are compressed. The compressed gases oppose the upward motion of the piston. However, almost all the energy stored in the compressed gases is returned to the crank shaft on the subsequent expansion stroke.

Thereby, during normal engine braking, the compression stroke together with the subsequent expansion stroke, will not contribute to a significant braking torque of the engine.

A compression release engine brake, sometimes referred to a Jake brake or Jacobs brake, is an engine braking mechanism used in some engines. Some compression release brake arrangements comprise a valve actuator assembly, which when activated, opens exhaust valves in the cylinders after the compression stroke, to release the compressed air trapped in the cylinders to the exhaust system. Thereby, the energy stored in the compressed gases during the compression stroke will not be returned to the crank shaft on the subsequent expansion stroke, which increases the braking torque of the engine. Some compression release engine brake arrangements comprise a hydraulic arrangement which actuates the valve actuator assembly by supplying a hydraulic pressure to the valve actuator assembly.

In some compression release engine brake arrangements, the exhaust valves may be deactivated, so that they remain closed during the exhaust stroke. Usually, this achieved by using a so called lost motion arrangement, which when actuated is arranged to not transfer motion caused by an exhaust cam lobe to the exhaust valve. The air in the cylinders will thereby be compressed also during the exhaust stroke. By using a valve actuator assembly opening exhaust valves near the end of the exhaust stroke, the compressed air trapped in the cylinders is released to the exhaust system. Thereby, the braking torque is almost doubled because compression and release events are performed in the compression stroke as well as in the exhaust stroke.

A compression release engine brake arrangement is a vital component of an engine, affects driveability of a vehicle, and affects functionality of other components a vehicle. If a compression release engine brake arrangement fails to activate braking, it will be noticed by a driver of the vehicle. If a compression release engine brake arrangement fails to deactivate braking, it may have consequences for other components of the engine. Further, if a compression release engine brake arrangement fails to deactivate braking, further travel with a vehicle will not possible because gases compressed during the compression stroke will be released from cylinders of the engine.

The malfunction of a compression release engine brake arrangement can for example be detected by monitoring variables such as engine pressures, engine speed, vehicle speed, and the like. Thus, a control unit may retrieve such variables, may calculate expected values, and may compare the retrieved variables with the expected variables, and may, based on such a comparison, or such comparisons, determine the function of the compression release brake arrangement. However, such a method is not very fast. Furthermore, such a method is not very reliable since the variables may also be affected by other factors than the functioning of the compression release brake arrangement.

SUMMARY

It is an object of the present invention to overcome, or at least alleviate, at least some of the above-mentioned problems and drawbacks.

According to a first aspect of the invention, the object is achieved by a compression release brake arrangement for an engine. The arrangement comprises a valve actuator assembly configured to, when activated, perform compression release braking of at least a first cylinder of the engine. The arrangement further comprises a hydraulic arrangement comprising a conduit arrangement, and a first and a second actuator valve arranged in the conduit arrangement. The conduit arrangement comprises a first conduit section connecting the first and the second actuator valves to the valve actuator assembly. The hydraulic arrangement is arranged such that the valve actuator assembly is activated when the first and second actuator valves are in an open state, and deactivated when at least one of the first and the second actuator valves is in a closed state. Thereby, a safer and more reliable compression release brake arrangement is provided. This because the hydraulic arrangement may deactivate the valve actuator assembly by closing one of the first and the second actuator valve, or by closing both the first and the second actuator valve.

That is, in embodiments where the hydraulic arrangement is configured to deactivate the valve actuator assembly by closing both the first and the second actuator valve, a correct functioning of at least one of the first and the second actuator valves is sufficient for ensuring deactivation of the valve actuator assembly. That is, even in cases where one of the first and the second actuator valves fails to assume the closed state, for some reason, the

deactivation of the valve actuator assembly is ensured.

In embodiments where the hydraulic arrangement is configured to deactivate the valve actuator assembly by closing for example the first actuator valve, and the first actuator valve fails to assume the closed state, for some reason, the second actuator valve can be controlled to the closed state to ensure deactivation of the valve actuator assembly.

Accordingly, a safer and more reliable compression release brake arrangement is provided, capable of reducing the risk of damage of other components of the engine.

Further, a compression release brake arrangement is provided capable of significantly reducing the risk of an unexpected stop of a vehicle caused by a malfunction of the compression release brake arrangement. As a further result thereof, a compression release brake arrangement is provided potentially improving driving safety of a vehicle hosting the compression release brake arrangement.

Accordingly, a compression release brake 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.

Optionally, the first and the second actuator valves are arranged in parallel in the conduit arrangement. Thereby, a safer and more reliable compression release brake arrangement is provided in a simple and efficient manner. Further, a compression release brake

arrangement is provided capable of activating and deactivating the valve actuator assembly in a quicker manner. Optionally, each of the first and the second actuator valve comprises a pressure reducer configured to reduce the pressure in the first conduit section, when the respective actuator valve is in the closed state. Thereby, a still safer and still more reliable compression release brake arrangement is provided, because deactivation of the valve actuator assembly, and thus also cancelation of compression release braking, is ensured when one of the first and second valves is controlled to the closed state.

Optionally, the arrangement further comprises a pressure sensor, and a control arrangement, wherein the pressure sensor is configured to sense fluid pressure in the first conduit section, and wherein the control arrangement is configured to activate the valve actuator assembly by controlling the first actuator valve to the open state, monitor the fluid pressure in the first conduit section, and then controlling the second actuator valve to the open state. Thereby, a compression release brake arrangement is provided where the control arrangement is provided with information indicative of the functioning of components of the hydraulic arrangement when activating the valve actuator assembly. Thus, a malfunction of a component of the hydraulic arrangement can be detected, and since the control arrangement is configured to monitor the fluid pressure in the first conduit section, such a malfunction can be detected within a short time-period. As a result, a still safer and still more reliable compression release brake arrangement is provided.

Optionally, the control arrangement is further configured to monitor the fluid pressure in the first conduit section after controlling the second actuator valve to the open state. Thereby, a compression release brake arrangement is provided where the control arrangement is provided with information indicative of the functioning of components of the hydraulic arrangement. Thus, a malfunction of a component of the hydraulic arrangement can be detected, and since the control arrangement is configured to monitor the fluid pressure in the first conduit section, such a malfunction can be detected within a short time-period. Further, the control arrangement is provided with information indicating whether the valve actuator assembly is activated. Thus, due to these features, a still safer and still more reliable compression release brake arrangement is provided.

Optionally, the arrangement further comprises a pressure sensor, and a control arrangement, wherein the pressure sensor is configured to sense fluid pressure in the first conduit section, and wherein the control arrangement is configured to deactivate the valve actuator assembly by controlling the first actuator valve to the closed state, monitor the fluid pressure in the first conduit section, and then controlling the second actuator valve to the closed state. Thereby, a compression release brake arrangement is provided where the control arrangement is provided with information indicative of the functioning of components of the hydraulic arrangement when deactivating the valve actuator assembly. Thus, a malfunction of a component of the hydraulic arrangement can be detected, and since the control arrangement is configured to monitor the fluid pressure in the first conduit section, such a malfunction can be detected within a short time-period. Further, a compression release brake arrangement is provided where two actuator valves, each capable of deactivating the valve actuator assembly, are controlled to a closed state when deactivating the valve actuator assembly. Thus, due to these features, a still safer and still more reliable compression release brake arrangement is provided.

Optionally, the control arrangement is further configured to monitor the fluid pressure in the first conduit section after controlling the second actuator valve to the closed state. Thereby, a compression release brake arrangement is provided where the control arrangement is provided with information indicative of the functioning of components of the hydraulic arrangement. Thus, a malfunction of a component of the hydraulic arrangement can be detected, and since the control arrangement is configured to monitor the fluid pressure in the first conduit section, such a malfunction can be detected within a short time-period. Further, a compression release brake arrangement is provided where the control arrangement is provided with information indicating whether the valve actuator assembly is deactivated.

Thus, due to these features, a still safer and still more reliable compression release brake arrangement is provided.

According to a second aspect of the invention, the object is achieved by an engine comprising a compression release brake arrangement according to some embodiments, and at least a first cylinder, wherein the compression release brake arrangement is configured to perform compression release braking of the at least first cylinder of the engine.

Thereby, an engine is provided comprising a safer and more reliable compression release brake arrangement. Thus, a safer and more reliable engine is provided, capable of reducing the risk of damage of other components of the engine.

Further, an engine is provided capable of significantly reducing the risk of an unexpected stop of a vehicle, hosting the engine, caused by a malfunction of the compression release brake arrangement of the engine. As a further result thereof, an engine is provided potentially improving driving safety of a vehicle hosting the engine. Accordingly, an engine 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.

According to a third aspect of the invention, the object is achieved by a vehicle comprising an engine according to some embodiments.

Since the vehicle comprises an engine according to some embodiments, a safer and more reliable vehicle is provided. Further, a vehicle is provided capable of significantly reducing the risk of an unexpected stop of a vehicle, caused by a malfunction of the compression release brake arrangement of the engine. As a further result thereof, a vehicle is provided with potentially improved driving safety.

Accordingly, a vehicle 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.

According to a fourth aspect of the invention, the object is achieved by a method of controlling a compression release brake arrangement for an engine, wherein the

arrangement comprises:

a valve actuator assembly configured to, when activated, perform compression release braking of at least a first cylinder of the engine, and

a hydraulic arrangement comprising a conduit arrangement, and a first and a second actuator valve arranged in the conduit arrangement, wherein the conduit arrangement comprises a first conduit section connecting the first and the second actuator valves to the valve actuator assembly, and

wherein the method comprises:

activating the valve actuator assembly by controlling the first and the second actuator valves to an open state, and

deactivating the valve actuator assembly by controlling at least one of the first and the second actuator valve to a closed state.

Since the method comprises the steps of activating the valve actuator assembly by controlling the first and the second actuator valves to an open state, and deactivating the valve actuator assembly by controlling at least one of the first and the second actuator valve to a closed state, a safer and more reliable method of controlling a compression release brake arrangement is provided. That is, in embodiments where the method comprises deactivating the valve actuator assembly by controlling for example the first actuator valve to a closed state, the second actuator valve can be controlled to the closed state, in case the first actuator valve, for some reason, fails to assume the closed state. In this manner, deactivation of the valve actuator assembly can be ensured.

In embodiments where the method comprises deactivating the valve actuator assembly by controlling both the first and the second actuator valve to a closed state, a correct functioning of at least one of the first and the second actuator valves is sufficient for ensuring

deactivation of the valve actuator assembly. That is, even in cases where one of the first and the second actuator valves fails to assume the closed state, for some reason, the deactivation of the valve actuator assembly is ensured.

Accordingly, a safer and more reliable method of controlling a compression release brake arrangement is provided, capable of reducing the risk of damage of other components of the engine.

Further, a method of controlling a compression release brake arrangement is provided capable of significantly reducing the risk of an unexpected stop of a vehicle caused by a malfunction of the compression release brake arrangement. As a further result thereof, a method of controlling a compression release brake arrangement is provided potentially improving driving safety of a vehicle hosting the compression release brake arrangement.

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.

Optionally, the arrangement further comprises a pressure sensor configured to sense fluid pressure in the first conduit section, and wherein the step of activating the valve actuator assembly comprises the steps of:

controlling the first actuator valve to the open state,

monitoring the fluid pressure in the first conduit section, and then controlling the second actuator valve to the open state.

Thereby, a method is provided obtaining information indicative of the functioning of components of the hydraulic arrangement, when activating the valve actuator assembly. Thus, a malfunction of a component of the hydraulic arrangement can be detected, and since the method comprises the step of monitoring the fluid pressure in the first conduit section, such a malfunction can be detected within a short time-period. As a result thereof, a still safer and still more reliable method is provided.

Optionally, the method further comprises:

monitoring the fluid pressure in the first conduit section after controlling the second actuator valve to the open state.

Thereby, a method is provided further obtaining information indicative of the functioning of components of the hydraulic arrangement. Thus, a malfunction of a component of the hydraulic arrangement can be detected, and since the method comprises the step of monitoring the fluid pressure in the first conduit section, such a malfunction can be detected within a short time-period. Further, a method is provided obtaining information indicating whether the valve actuator assembly is activated. Thus, due to these features, a still safer and still more reliable method is provided.

Optionally, the arrangement further comprises a pressure sensor configured to sense fluid pressure in the first conduit section, and wherein the step of deactivating the valve actuator assembly comprises the steps of:

controlling the first actuator valve to the closed state,

monitoring the fluid pressure in the first conduit section, and then controlling the second actuator valve to the closed state.

Thereby, a method is provided obtaining information indicative of the functioning of components of the hydraulic arrangement, when deactivating the valve actuator assembly. Thus, a malfunction of a component of the hydraulic arrangement can be detected, and since the method comprises the step of monitoring the fluid pressure in the first conduit section, such a malfunction can be detected within a short time-period. Further, a method is provided where two actuator valves, each capable of deactivating the valve actuator assembly, are controlled to a closed state when deactivating the valve actuator assembly. Thus, due to these features, a still safer and still more reliable method is provided.

Optionally, the method further comprises:

monitoring the fluid pressure in the first conduit section after controlling the second actuator valve to the closed state. Thereby, a method is provided further obtaining information indicative of the functioning of components of the hydraulic arrangement. Thus, a malfunction of a component of the hydraulic arrangement can be detected, and since the method comprises the step of monitoring the fluid pressure in the first conduit section, such a malfunction can be detected within a short time-period. Further, a method is provided obtaining information indicating whether the valve actuator assembly is deactivated. Thus, due to these features, a still safer and still more reliable method is provided.

According to a fifth 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 carry out the method according to some embodiments.

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 some embodiments, 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.

According to a sixth 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 carry out the method according to some embodiments.

Since the computer-readable medium comprises instructions which, when executed by a computer, cause the computer to carry out the method according to some embodiments, 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.

According to a seventh aspect of the invention, the object is achieved by a control arrangement for a compression release brake arrangement of an engine, wherein the compression release brake arrangement comprises:

a hydraulic arrangement comprising a conduit arrangement, and a first and a second actuator valve arranged in the conduit arrangement, wherein the conduit arrangement comprises a first conduit section connecting the first and the second actuator valves to the valve actuator assembly, and wherein control arrangement is configured to:

activate the valve actuator assembly by controlling the first and the second actuator valves to an open state, and

deactivate the valve actuator assembly by controlling at least one of the first and the second actuator valve to a closed state.

Thereby, a control arrangement is provided capable of controlling a compression release brake arrangement in a safer and more reliable manner. This because the control arrangement may deactivate the valve actuator assembly by closing one of the first and the second actuator valve, or by closing both the first and the second actuator valve.

That is, in embodiments where the control arrangement is configured to deactivate the valve actuator assembly by closing both the first and the second actuator valve, a correct functioning of at least one of the first and the second actuator valves is sufficient for ensuring deactivation of the valve actuator assembly. That is, even in cases where one of the first and the second actuator valves fails to assume the closed state, for some reason, the

deactivation of the valve actuator assembly is ensured.

In embodiments where the control arrangement is configured to deactivate the valve actuator assembly by closing for example the first actuator valve, and the first actuator valve fails to assume the closed state, for some reason, the second actuator valve can be controlled to the closed state to ensure deactivation of the valve actuator assembly.

Accordingly, a safer and more reliable control arrangement is provided, capable of reducing the risk of damage of components of an engine.

Further, a control arrangement is provided capable of significantly reducing the risk of an unexpected stop of a vehicle caused by a malfunction of a compression release brake arrangement. As a further result thereof, a control arrangement is provided potentially improving driving safety of a vehicle hosting the control arrangement.

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.

Further features of, and advantages with, the present invention will become apparent when studying the appended claims and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects of the invention, 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:

Fig. 1 schematically illustrates a compression release brake arrangement, according to some embodiments,

Fig. 2 schematically illustrates an engine, according to some embodiments,

Fig. 3 illustrates a vehicle, according to some embodiments,

Fig. 4 illustrates a method of controlling a compression release brake arrangement, and Fig. 5 illustrates computer-readable medium, according to some embodiments.

DETAILED DESCRIPTION

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

Fig. 1 schematically illustrates a compression release brake arrangement 1 , according to some embodiments. The compression release brake arrangement 1 is configured to selectively perform compression release braking of an engine. The compression release brake arrangement 1 comprises a valve actuator assembly 5 configured to, when activated, perform compression release braking of at least a first cylinder 7’ of the engine 3. In Fig. 1 , the first cylinder 7’ is schematically illustrated as a dashed box.

For the reason of brevity and/or clarity, the compression release brake arrangement 1 is in some places herein referred to as“the arrangement 1”. The arrangement 1 comprises a hydraulic arrangement 8 comprising a conduit arrangement 9, and a first and a second actuator valve 1 1 , 12 arranged in the conduit arrangement 9. The hydraulic arrangement 8 is configured to control operation of the valve actuator assembly 5. The first and the second actuator valves 1 1 , 12 are arranged to control flow of hydraulic fluid in the conduit arrangement 9. The conduit arrangement 9 comprises a first conduit section 9’ connecting the first and the second actuator valves 1 1 , 12 to the valve actuator assembly 5. Further, the conduit arrangement 9 comprises a second conduit section 9” connecting the first and the second actuator valves 1 1 , 12 to a pressure source 13. The pressure source 13 may comprise a hydraulic component connected to an engine oil circuit of the engine. The engine oil circuit of an engine is pressurized, during operation of the engine, due to pumping action of a lubricant pump of an engine. The pressure of oil in an engine oil circuit can for example be within the range of 2 - 8 bars.

The hydraulic arrangement 8 is arranged such that the valve actuator assembly 5 is activated, when each of the first and second actuator valves 1 1 , 12 are in an open state, and deactivated when at least one of the first and the second actuator valves 1 1 , 12 is in a closed state. Further, the arrangement 1 comprises a control arrangement 21 , configured to control the first and second actuator valve 1 1 , 12.

According to the illustrated embodiments, the valve actuator assembly 5 is actuated when subjected to a fluid pressure above a predetermined threshold level, and deactivated when subjected to a fluid pressure below the predetermined threshold level. The pressure level of the pressure source 13 is above the predetermined threshold level, when the engine is running. The first and the second actuator valves 1 1 , 12 are each arranged to open a respective fluid connection between the first and second conduit section 9’, 9” when in the open state. Thereby, an open connection is formed between the pressure source 13 and the valve actuator assembly 5 when the first and the second actuator valves 1 1 , 12 are in the open state. As a result thereof, the valve actuator assembly 5 is subjected to a pressure above the predetermined threshold level. Thereby, the valve actuator assembly 5 will perform compression release braking of the first cylinder 7’.

The first and the second actuator valves 1 1 , 12 are each arranged to close a respective fluid connection between the first and second conduit section 9’, 9” when in the closed state. Further, according to the illustrated embodiments, each of the first and the second actuator valve 1 1 , 12 comprises a pressure reducer 17’, 17” configured to reduce the pressure in the first conduit section 9’ to a pressure level below the predetermined threshold level, when the respective actuator valve 1 1 , 12 is in the closed state. As a result thereof, the valve actuator assembly 5 will be subjected to a pressure below the predetermined threshold level in case one of, as well as in case both of, the first and second actuator valve 1 1 , 12 is in the closed state. Accordingly, the valve actuator assembly 5 will cancel compression release braking of the first cylinder T when one of, or both of, the first and second actuator valve 1 1 , 12 is in the closed state. Since the arrangement 1 comprises two actuator valves 1 1 , 12 capable of cancelling compression release braking, a safer and more reliable compression release brake arrangement 1 is provided.

According to the illustrated embodiments, the first and the second actuator valves 1 1 , 12 are arranged in parallel in the conduit arrangement 9. As a result thereof, a compression release brake arrangement 1 is provided capable of providing a quicker activation and a quicker deactivation of the valve actuator assembly 5. The quicker activation of the valve actuator assembly 5 can be performed by simultaneously opening the first and the second actuator valves 1 1 , 12. As a result thereof, a quicker rise in pressure in the first conduit section 9’ is provided, which reduces the activation time of the valve actuator assembly 5. The quicker deactivation of the valve actuator assembly 5 can be performed by simultaneously closing the first and the second actuator valves 1 1 , 12. As a result thereof, a quicker decrease in pressure in the first conduit section 9’ is provided, which reduces the deactivation time of the valve actuator assembly 5. According to further embodiments, the first and the second actuator valves 1 1 , 12 may be arranged in series in the conduit arrangement 9.

The pressure reducers 17’, 17” of the first and the second actuator valves 1 1 , 12 may be configured to reduce the pressure in the first conduit section 9’ by opening a connection between the first conduit section 9’ and a portion of a hydraulic arrangement having a low pressure level, such as a tank or an inlet of a pump.

Below the valve actuator assembly 5 as referred to herein will be described in more detail. According to the illustrated embodiments, the valve actuator assembly 5 comprises a compression release brake valve 2 and a valve actuator 4. The compression release brake valve 2 is connected to the first conduit section 9’. The valve actuator 4 comprises a portion of a camshaft 6 comprising a cam lobe 6’ and a hydraulic component 10 comprising a fluid chamber 10’. The camshaft 6 is configured to rotate upon rotation of a crankshaft of the engine. The compression release brake valve 2 is configured to assume a first state when the pressure in the first conduit section 9’ is above the predetermined threshold level. The compression release brake valve 2 is configured to assume a second state when the pressure in the first conduit section 9’ is below the predetermined threshold level. When the compression release brake valve 2 is in the first state it allows transport of fluid into the fluid chamber 10’. Thus, the fluid chamber 10’ of the hydraulic component 10 is filled with fluid, e.g., engine oil, when the compression release brake valve 2 is in the first state. In addition, when the pressure in the first conduit section 9’ is above the predetermined threshold level, i.e. when the compression release brake valve 2 is in the first state, the compression release brake valve 2 also hiders transport of fluid out of the fluid chamber 10’. As a result, when the cam lobe 6’ abuts against the hydraulic component 10, an exhaust valve 14 of the engine is opened. This because the motion of the cam lobe 6’ can be transferred to an opening motion of the exhaust valve 14. The camshaft 6 and the cam lobe 6’ are provided such that the opening occurs towards the end of a compression stroke of the first cylinder 7’. As a result, gases compressed during the compression stroke are released from the first cylinder 7’. Thus, the control arrangement 21 can activate the valve actuator assembly 5 to perform compression release braking of the first cylinder 7’ of the engine, simply by controlling the first and second actuator valves 1 1 , 12 to an open state.

In order to deactivate the valve actuator assembly 5, the control arrangement 21 can close one of the first and second actuator valves 1 1 , 12. When one of the first and second actuator valves 1 1 , 12 closes, a pressure reducer 17’, 17” of the actuator valve 1 1 , 12 will reduce the pressure in first conduit section 9’ to a pressure level below the predetermined threshold level. Thereby, the compression release brake valve 2 is subjected to a pressure below the predetermined threshold level and the compression release brake valve 2 will as a result thereof assume the second state. When in the second state, the compression release brake valve 2 is configured to allow fluid transport out of the fluid chamber 10’ of the hydraulic component 10. Thereby, no motion is transferred from the cam lobe 6’ to the exhaust valve 14 when the cam lobe 6’ abuts against the hydraulic component 10. This because fluid can flow out of the fluid chamber 10’ when a portion of the fluid component 10 is displaced by the cam lobe 6’. As a result, the exhaust valve 14 will remain closed towards the end of a compression stroke of the first cylinder 7’. Thus, the control arrangement 21 can deactivate the valve actuator assembly 5, to cancel the compression release braking of the first cylinder 7’ of the engine, simply by controlling one of the first and second actuator valves 1 1 , 12 to a closed state.

According to the illustrated embodiments, the compression release brake arrangement 1 comprises a pressure sensor 19 configured to sense fluid pressure in the first conduit section 9’. The control arrangement 21 is connected to the pressure sensor 19. According to these embodiments, the control arrangement 21 is configured to activate the valve actuator assembly 5 by controlling the first actuator valve 1 1 to the open state, monitor the fluid pressure in the first conduit section 9’, and then controlling the second actuator valve 12 to the open state. Thereby, the control arrangement 21 is provided with information indicative of the functioning of components of the hydraulic arrangement 8. That is, when controlling the first actuator valve 1 1 to the open state, the fluid pressure in the first conduit section 9’ is expected to not rise. However, if a rise in fluid pressure in the first conduit section 9’ is monitored when controlling first actuator valve 1 1 to the open state, the second actuator valve 12 can be expected to be stuck in the open state. In response thereto, the control arrangement 21 may issue an error code to a control system of the engine, and/or a control system of the vehicle, hosting the compression release brake arrangement 1. However, even if such a malfunction of the second actuator valve 12 is detected, the valve actuator assembly 5 can still be deactivated, as well as activated, by controlling the opening state of the first actuator valve 1 1.

As is evident from the above, if no rise in fluid pressure in the first conduit section 9’ is monitored when controlling first actuator valve 1 1 to the open state, the components of the hydraulic arrangement 8 can be expected to work as intended. As mentioned, the control arrangement 21 is configured to activate the valve actuator assembly 5 by controlling the first actuator valve 1 1 to the open state, monitor the fluid pressure in the first conduit section 9’, and then controlling the second actuator valve 12 to the open state. According to some embodiments, the control arrangement 21 is further configured to monitor the fluid pressure in the first conduit section 9’ after controlling the second actuator valve 12 to the open state. Thereby, the control arrangement 21 is further provided with information indicative of the functioning of components of the hydraulic arrangement 8. That is, when controlling the second actuator valve 12 to the open state, the fluid pressure in the first conduit section 9’ is expected to rise. However, if no rise in fluid pressure in the first conduit section 9’ is monitored when controlling second actuator valve 12 to the open state, a component of the hydraulic arrangement 8 can be expected to not work as intended. In response thereto, the control arrangement 21 may issue an error code to a control system of the engine, and/or a control system of the vehicle, hosting the compression release brake arrangement 1 . If a rise in fluid pressure in the first conduit section 9’ is monitored when controlling second actuator valve 12 to the open state, the components of the hydraulic arrangement can be expected to work as intended, and the control arrangement 21 is thereby also provided with information indicating that the valve actuator assembly 5 is activated.

Further, according to the illustrated embodiments, the control arrangement 21 is configured to deactivate the valve actuator assembly 5 by controlling the first actuator valve 1 1 to the closed state, monitor the fluid pressure in the first conduit section 9’, and then controlling the second actuator valve 12 to the closed state. Thereby, the control arrangement 21 is provided with information indicative of the functioning of components of the hydraulic arrangement 8. That is, when controlling the first actuator valve 1 1 to the closed state, the fluid pressure in the first conduit section 9’ is expected to decrease. However, if no decrease in fluid pressure in the first conduit section 9’ is monitored, when controlling the first actuator valve 1 1 to the closed state, the first actuator valve 1 1 can be expected to be stuck in the open state. In response thereto, the control arrangement 21 may control the second actuator valve 12 to the closed state, and may issue an error code to a control system of the engine, and/or a control system of the vehicle, hosting the compression release brake arrangement 1. The control arrangement 21 is further configured to monitor the fluid pressure in the first conduit section 9’ after controlling the second actuator valve 12 to the closed state. If a decrease in fluid pressure in the first conduit section 9’ is monitored, the second actuator valve 12 can be expected to work as intended and the control arrangement 21 is thus provided with information indicating that the valve actuator assembly 5 is deactivated. If no decrease in fluid pressure in the first conduit section 9’ is monitored when controlling the second actuator valve 12 to the closed state, the second actuator valve 12 can be expected to be stuck in the open state. In response thereto, the control arrangement 21 may issue an error code to a control system of the engine, and/or a control system of the vehicle, hosting the compression release brake arrangement 1 , and may perform further safety measures, such as activating a warning light, and/or warning sound, in a driver environment of a vehicle hosting the compression release brake arrangement 1 .

Fig. 2 schematically illustrates an engine 3, according to some embodiments. The engine 3 comprises four cylinders 7’, 7”, 7’”, 7”” arranged in line. The engine 3 illustrated in Fig. 2 may thus be referred to as an inline-four cylinder engine. The engine 3 may comprise another number of cylinders than four, which may be arranged in another configuration than in inline, as is further explained herein.

The engine 3 comprises a compression release brake arrangement 1 configured to perform compression release braking of at least one cylinder 7’ of the engine 3. Below, reference is made to Fig. 2, as well as to Fig. 1. The engine 3 may comprise one compression release brake arrangement 1 per cylinder 7’, 7”, 7’”, 7””. Thus, according to such embodiments, the engine 3 illustrated in Fig. 2 may comprise four valve actuator assemblies 5, four hydraulic arrangements 8, and four pressure sensors 19. The control arrangement 21 may be connected to each actuator valve 1 1 , 12 of each hydraulic arrangement 8 and to each pressure sensor 19. Thereby, an individual activation, and cancelation, of compression release braking can be performed of each cylinder 7’, 7”, 7’”, 7””. Further, the detection of a malfunction of an actuator valve of a compression release brake arrangement 1 can be performed individually per cylinder 7’, 7”, 7’”, 7””.

According to further embodiments, the engine 3 may comprise one or more hydraulic arrangements 8 each connected to several valve actuator assemblies 5. Thus, according to such embodiments, the first conduit section 9’ of a hydraulic arrangement 8 is connected to several valve actuator assemblies 5 each configured to perform compression release braking of a cylinder 7’, 7”, 7’”, 7””. For example, the engine 3 may comprise a first hydraulic arrangement configured to activate, and deactivate, compression release braking of a first set of cylinders 7’, 7’”, and a second hydraulic arrangement configured to activate, and deactivate, compression release braking of a second set of cylinders 7”, 7””.

According to some embodiments, the engine 3 comprises cylinders arranged in V- configuration, such as a V-6 or V-8 engine. Thus, in such embodiments, the cylinders of the engine are arranged in a first row and in a second row. According to such embodiments, the engine may comprise a first hydraulic arrangement, according to the embodiments illustrated in Fig. 1 , wherein the first conduit section 9’ of the first hydraulic arrangement is connected to valve actuator assemblies of cylinders of the first row of cylinders, and a second hydraulic arrangement, according to the embodiments illustrated in Fig. 1 , wherein the first conduit section 9’ of the second hydraulic arrangement is connected to connected to valve actuator assemblies of cylinders of the second row of cylinders. Thus, according to such

embodiments, the control arrangement may perform activation and deactivation of valve actuator assemblies per row of cylinders, to perform a 50% compression release braking of the engine 3, a full compression release braking of the engine 3, or a deactivation of compression release braking of the engine 3.

The engine 3, as referred to herein, may be referred to as an internal combustion engine, and may for example be a compression ignition engine, such as a diesel engine, or an Otto engine with a spark-ignition device, wherein the Otto engine may be configured to run on gas, petrol, alcohol or similar volatile fuels or combinations thereof.

Fig. 3 illustrates a vehicle 25, according to some embodiments. The vehicle 25 comprises wheels 31 and an engine 3 according to the embodiments illustrated in Fig. 2. The engine 3 is configured to provide motive power to the vehicle 25 via one or more of the wheels 31 of the vehicle 25. The vehicle 25 illustrated in Fig. 3 is a truck. Flowever, the engine 3, as referred to herein, may be comprised in another type of manned or unmanned vehicle for land or water based propulsion such as a lorry, a bus, a construction vehicle, a tractor, a car, a boat, a ship or the like. Further, the engine 3, as referred to herein, may be a stationary internal combustion engine, for example an internal combustion engine of an engine driven generator.

Fig. 4 illustrates a method 100 of controlling a compression release brake arrangement for an engine. The compression release brake arrangement may be a compression release brake arrangement 1 according to the embodiments illustrated in Fig. 1 , and the engine may be an engine 3 according to embodiments illustrated in Fig. 2. Therefore, below, reference is made to Fig. 4 as well as to Fig. 1 and Fig. 2. The method 100, illustrated in Fig. 4, is a method 100 of controlling a compression release brake arrangement 1 for an engine 3, wherein the arrangement 1 comprises:

a valve actuator assembly 5 configured to, when activated, perform compression release braking of at least a first cylinder 7’ of the engine 3, and a hydraulic arrangement 8 comprising a conduit arrangement 9, and a first and a second actuator valve 1 1 , 12 arranged in the conduit arrangement 9, wherein the conduit arrangement 9 comprises a first conduit section 9’ connecting the first and the second actuator valves 1 1 , 12 to the valve actuator assembly 5, and

wherein the method 100 comprises:

activating 1 10 the valve actuator assembly 5 by controlling the first and the second actuator valves 1 1 , 12 to an open state, and

deactivating 120 the valve actuator assembly 5 by controlling at least one of the first and the second actuator valves 1 1 , 12 to a closed state.

According to some embodiments, the arrangement 1 further comprises a pressure sensor 19 configured to sense fluid pressure in the first conduit section 9’, and wherein the step of activating 1 10 the valve actuator assembly 5 comprises the steps of:

controlling 1 12 the first actuator valve 1 1 to the open state,

monitoring 1 14 the fluid pressure in the first conduit section 9’, and then controlling 1 16 the second actuator valve 12 to the open state.

According to some embodiments, the method 100 further comprises:

monitoring 1 18 the fluid pressure in the first conduit section 9’ after controlling the second actuator valve 12 to the open state.

According to some embodiments, the arrangement 1 further comprises a pressure sensor 19 configured to sense fluid pressure in the first conduit section 9’, and wherein the step of deactivating 120 the valve actuator assembly 5 comprises the steps of:

controlling 122 the first actuator valve 1 1 to the closed state,

monitoring 124 the fluid pressure in the first conduit section 9’, and then controlling 126 the second actuator valve 12 to the closed state.

According to some embodiments, the method 100 further comprises:

monitoring 128 the fluid pressure in the first conduit section 9’ after controlling the second actuator valve 12 to the closed state. 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 1 10, 1 12, 1 14,

1 16, 1 18, 120, 122, 124, 126, and 128 of the method 100.

Fig. 5 illustrates computer-readable medium 200, according to some embodiments. The computer-readable medium 200 comprises instructions which, when executed by a computer, cause the computer to carry out the method 100 according to some embodiments described herein.

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 control arrangement 21 , as referred to herein, may be connected to one or more components of the engine 3, and to one or more components of compression release brake arrangement 1 , such as the first actuator valve 1 1 , the second valve 12, the pressure sensor 19, in order to perform the method 100 illustrated in Fig. 4.

One skilled in the art will appreciate that the method 100 of controlling a compression release brake arrangement 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 1 10, 1 12, 1 14, 1 16, 1 18, 120, 122, 124, 126, and 128 described herein. The computer program is usually part of a computer program product 200 which comprises a suitable digital storage medium on which the computer program is stored.

The control arrangement 21 may comprise a calculation unit which may take the form of substantially any suitable type of processor circuit or microcomputer, e.g. a circuit for digital signal processing (digital signal processor, DSP), a Central Processing Unit (CPU), a processing unit, a processing circuit, a processor, an Application Specific Integrated Circuit (ASIC), a microprocessor, or other processing logic that may interpret and execute instructions. The herein utilised expression“calculation unit” may represent a processing circuitry comprising a plurality of processing circuits, such as, e.g., any, some or all of the ones mentioned above. The control arrangement 21 may further comprise a memory unit, wherein the calculation unit may be connected to the memory unit, which may provide the calculation unit with, for example, stored program code and/or stored data which the calculation unit may need to enable it to do calculations. The calculation unit 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.

The control arrangement 21 is connected to components of the compression release brake arrangement 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 to signals processable by the control arrangement 21. These signals may then be supplied to the calculation unit. One or more output signal sending devices may be arranged to convert calculation results from the calculation unit 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 compression release brake arrangement 1 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 compression release brake arrangement 1 comprises a control arrangement 21 but might alternatively be implemented wholly or partly in two or more control arrangements or two or more control units.

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 of the type here concerned are therefore often provided with significantly more control arrangements than depicted in Fig. 1 as one skilled in the art will surely appreciate. The computer program product 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 1 10, 1 12, 1 14, 1 16, 1 18, 120, 122, 124, 126, and 128 according to some embodiments when being loaded into one or more calculation units of the control arrangement 21. The data carrier may be, e.g. a CD ROM disc, as is illustrated in Fig. 5, 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. The computer program product 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. It is to be understood that the foregoing is illustrative of various example embodiments and that the invention is defined only by the appended 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 claims.

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 the presence or addition of one or more other features, elements, steps, components, functions or groups thereof.

Claims

1. A compression release brake arrangement (1 ) for an engine (3), wherein the

arrangement (1 ) comprises:

- a valve actuator assembly (5) configured to, when activated, perform

compression release braking of at least a first cylinder (7’) of the engine (3), and

- a hydraulic arrangement (8) comprising a conduit arrangement (9), and a first and a second actuator valve (1 1 , 12) arranged in the conduit arrangement (9), wherein the conduit arrangement (9) comprises a first conduit section (9’) connecting the first and the second actuator valves (1 1 , 12) to the valve actuator assembly (5),

and wherein the hydraulic arrangement (8) is arranged such that the valve actuator assembly is activated (5) when the first and second actuator valves (1 1 , 12) are in an open state, and deactivated when at least one of the first and the second actuator valves (1 1 , 12) is in a closed state.

2. The arrangement (1 ) according to claim 1 , wherein the first and the second actuator valves (1 1 , 12) are arranged in parallel in the conduit arrangement (9).

3. The arrangement (1 ) according to claim 1 or 2, wherein each of the first and the second actuator valve (1 1 , 12) comprises a pressure reducer (17’, 17”) configured to reduce the pressure in the first conduit section (9’), when the respective actuator valve (1 1 , 12) is in the closed state.

4. The arrangement (1 ) according to any one of the preceding claims, wherein the

arrangement (1 ) further comprises a pressure sensor (19), and a control arrangement (21 ), wherein the pressure sensor (19) is configured to sense fluid pressure in the first conduit section (9’), and wherein the control arrangement (21 ) is configured to activate the valve actuator assembly (5) by controlling the first actuator valve (1 1 ) to the open state, monitor the fluid pressure in the first conduit section (9’), and then controlling the second actuator valve (12) to the open state.

5. The arrangement (1 ) according to claim 4, wherein the control arrangement (21 ) is

further configured to monitor the fluid pressure in the first conduit section (9’) after controlling the second actuator valve (12) to the open state.

6. The arrangement (1 ) according to any one of the preceding claims, wherein the

arrangement (1 ) further comprises a pressure sensor (19), and a control arrangement (21 ), wherein the pressure sensor (19) is configured to sense fluid pressure in the first conduit section (9’), and wherein the control arrangement (21 ) is configured to deactivate the valve actuator assembly (5) by controlling the first actuator valve (1 1 ) to the closed state, monitor the fluid pressure in the first conduit section (9’), and then controlling the second actuator valve (12) to the closed state.

7. The arrangement (1 ) according to claim 6, wherein the control arrangement (21 ) is

further configured to monitor the fluid pressure in the first conduit section (9’) after controlling the second actuator valve (12) to the closed state.

8. An engine (3) comprising a compression release brake arrangement (1 ) according to any one of the preceding claims, and at least a first cylinder (7’), wherein the compression release brake arrangement (1 ) is configured to perform compression release braking of the at least first cylinder (7’) of the engine (3).

9. A vehicle (25) comprising an engine (3) according to claim 8.

10. A method (100) of controlling a compression release brake arrangement (1 ) for an

engine (3), wherein the arrangement (1 ) comprises:

- a valve actuator assembly (5) configured to, when activated, perform

- a hydraulic arrangement (8) comprising a conduit arrangement (9), and a first and a second actuator valve (1 1 , 12) arranged in the conduit arrangement (9), wherein the conduit arrangement (9) comprises a first conduit section (9’) connecting the first and the second actuator valves (1 1 , 12) to the valve actuator assembly (5), and

wherein the method (100) comprises:

- activating (1 10) the valve actuator assembly (5) by controlling the first and the second actuator valves (1 1 , 12) to an open state, and

- deactivating (120) the valve actuator assembly (5) by controlling at least one of the first and the second actuator valves (1 1 , 12) to a closed state.

1 1 . The method (100) according to claim 10, wherein the arrangement (1 ) further comprises a pressure sensor (19) configured to sense fluid pressure in the first conduit section (9’), and wherein the step of activating (1 10) the valve actuator assembly (5) comprises the steps of:

- controlling (1 12) the first actuator valve (1 1 ) to the open state,

- monitoring (1 14) the fluid pressure in the first conduit section (9’), and then

- controlling (1 16) the second actuator valve (12) to the open state.

12. The method (100) according to claim 1 1 , wherein the method (100) further comprises:

- monitoring (1 18) the fluid pressure in the first conduit section (9’) after controlling the second actuator valve (12) to the open state.

13. The method (100) according to any one of the claims 10 - 12, wherein the arrangement (1 ) further comprises a pressure sensor (19) configured to sense fluid pressure in the first conduit section (9’), and wherein the step of deactivating (120) the valve actuator assembly (5) comprises the steps of:

- controlling (122) the first actuator valve (1 1 ) to the closed state,

- monitoring (124) the fluid pressure in the first conduit section (9’), and then

- controlling (126) the second actuator valve (12) to the closed state.

14. The method (100) according to claim 13, wherein the method (100) further comprises:

- monitoring (128) the fluid pressure in the first conduit section (9’) after controlling the second actuator valve (12) to the closed state.

15. 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 the claims 10 - 14.

16. A computer-readable medium (200) comprising instructions which, when executed by a computer, cause the computer to carry out the method (100) according to any one of the claims 10 - 14.

17. A control arrangement (21 ) for a compression release brake arrangement (1 ) of an engine (3), wherein the compression release brake arrangement (1 ) comprises:

- a valve actuator assembly (5) configured to, when activated, perform

wherein control arrangement (21 ) is configured to:

- activate the valve actuator assembly (5) by controlling the first and the second actuator valves (1 1 , 12) to an open state, and deactivate the valve actuator assembly (5) by controlling at least one of the first and the second actuator valves (1 1 , 12) to a closed state.