Method for operating combustion engine, computer program, computer-readable medium, control device, combustion engine and vehicle

Abstract

A method (100) of operating an internal combustion engine (1) is disclosed, the internal combustion engine (1) comprising a plurality of cylinders (c1-c5). The method (100) comprises the steps of: operating (110) a first set (s1) of cylinders (c1-c3) in a compression release mode; operating (120) a second group (s2) of cylinders (c4, c5) in a motorized mode; and initiating (130) operation of the power mode of the second set (s2) of cylinders (c4, c5) upon receipt of the compression release mode deactivation demand (Cbd). The disclosure also relates to a computer program, a computer readable medium (200), a control device (21), an internal combustion engine (1) and a vehicle (2).

Description

Technical Field

[0001] The present disclosure relates to a method of operating an internal combustion engine. The present disclosure also relates to a computer program, a computer-readable medium, a control device for an internal combustion engine, an internal combustion engine including a plurality of cylinders and a control device, and a vehicle including an internal combustion engine. Background Art

[0002] An internal combustion engine, such as a four-stroke internal combustion engine, includes one or more cylinders and pistons arranged in each cylinder. The pistons are connected to the crankshaft of the engine and are arranged to reciprocate within the cylinders as the crankshaft rotates. The engine typically also includes one or more intake valves and outlet valves and one or more fuel supply devices. The one or more intake valves and outlet valves are controlled by respective valve control devices, which typically include one or more camshafts rotatably connected to the crankshaft of the engine via a belt, chain, gear, or the like. A four-stroke internal combustion engine completes four separate strokes while rotating the 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 typically referred to as top dead center (TDC), while the lowermost position of the piston in the cylinder is typically referred to as bottom dead center (BDC).

[0003] The strokes are completed in the following order: intake stroke, compression stroke, expansion stroke, and exhaust stroke. During the intake stroke of the piston within the cylinder in a conventional four-stroke internal combustion engine, the intake valve control device controls the intake valve of the cylinder to an open state 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 air and fuel in the cylinder. If the engine is in a power generation state, typically near the end of the compression stroke, the fuel in the cylinder is ignited, for example, by a spark plug or by the compression heat in the cylinder. The combustion of the fuel in the cylinder significantly increases the pressure and temperature within the cylinder. The combustion of the fuel typically continues through most of the subsequent expansion stroke. The increased pressure and temperature in the cylinder obtained by combustion are partially converted into mechanical work supplied to the crankshaft during the expansion stroke. Obviously, during the expansion stroke, all valves should remain closed to allow the conversion of the increased pressure and temperature into mechanical work. The expansion stroke is also typically referred to as the combustion stroke because typically most of the combustion occurs during the expansion stroke. In the subsequent exhaust stroke, the exhaust valve control device controls the exhaust valve of the cylinder to an open state to allow the exhaust gas to be discharged from the cylinder into the exhaust system of the combustion engine.

[0004] During a maneuver that occurs, for example, when a vehicle driver releases the accelerator pedal, the engine will continue to operate in the above-described strokes, except that fuel is not supplied to the engine during the maneuver. Therefore, combustion will not occur during the end of the compression stroke or during the expansion stroke. In this case, the engine will provide some braking torque during the respective intake and exhaust strokes due to internal friction and due to air being pumped from the intake valve to the exhaust valve. When the piston travels upward during its compression stroke, the gas trapped in the cylinder is compressed. The compressed gas resists the upward movement of the piston. However, almost all of the energy stored in the compressed gas returns to the crankshaft during the subsequent expansion stroke. Thus, during the maneuver, the compression stroke together with the subsequent expansion stroke will not impose a significant braking torque on the engine.

[0005] Some regulations require heavier vehicles to be equipped with an auxiliary braking system in addition to wheel brakes. An effective means of braking a vehicle is to use the engine to provide additional braking force, since the vehicle's existing systems can be used to generate the required braking force and transfer the heat generated during braking to the surrounding environment. In addition, using the engine to provide additional braking force reduces wear on the wheel brakes.

[0006] There are some different types of methods and devices for increasing the braking torque of an engine. Compression release engine brakes (sometimes also called Jake brakes, Jacobs brakes, or CRBs (compression release brakes)) are engine braking mechanisms used in some engines. Some compression release braking devices include a valve actuator assembly that is configured to open the exhaust valve in the cylinder after the compression stroke to release the compressed air trapped in the cylinder to the exhaust system. Thus, the energy stored in the compressed gas during the compression stroke will not return to the crankshaft during the subsequent expansion stroke, which increases the braking torque of the engine. Some compression release engine braking devices include a hydraulic device that actuates the valve actuator assembly by supplying hydraulic pressure to the valve actuator assembly.

[0007] Compression release engine brakes are now commonly used as auxiliary brakes for heavy-duty vehicles such as trucks equipped with internal combustion engines. In many applications, an efficient compression release engine brake can replace a retarder, which can save the cost of the vehicle, reduce complexity, and reduce weight. However, a problem associated with compression release engine brake devices is that deactivating the compression release brake can take a relatively long time, especially in some situations and during some conditions. The relatively long deactivation time of compression release braking can affect the driving feel of the vehicle. In addition, this can affect the function of the anti-lock braking system (ABS), since these types of systems generally require a rapid reduction in braking torque to avoid or counteract wheel slip.

[0008] Some regulations allow a vehicle to tow a trailer and require the ability to maintain a certain speed on a slope with a predetermined gradient and length at a specific vehicle weight. For a vehicle equipped with a compression release engine brake as the main auxiliary brake, to meet such regulations, it is important that the compression release engine brake operates within a wide range of vehicle and ambient temperatures.

[0009] For example, due to increased drag losses in the propulsion system, driven axles, non-driven axles, etc., a cold vehicle may meet such regulations, but as the temperature rises, the losses decrease, and it may be crucial for the compression release engine brake to operate before the drag losses decrease so much that the regulations are no longer met without using the compression release engine brake.

[0010] As previously mentioned, the relatively long deactivation time of the compression release engine brake may affect the function of the anti-lock braking system, and under certain conditions, it may be difficult to deactivate the compression release engine brake quickly enough. This in turn leads to the need to delay the use of the compression release engine brake until the deactivation time of the compression release engine brake is below a certain threshold time. As a result, when the total braking power is too low due to reduced drag losses during vehicle warm-up, the regulation may not be met. Therefore, the vehicle may have to be equipped with another type of auxiliary braking system, such as a hydraulic retarder, etc., in order to be able to comply with the regulation. Such an auxiliary braking system increases the cost, complexity, and weight of the vehicle. Summary of the Invention

[0011] The object of the present invention is to overcome or at least mitigate at least some of the above problems and disadvantages.

[0012] According to a first aspect of the present invention, the object is achieved by a method of operating an internal combustion engine, the internal combustion engine comprising a plurality of cylinders, wherein the method comprises the following steps:

[0013] - Operating a first set of the plurality of cylinders in a compression release mode,

[0014] - Operating a second set of the plurality of cylinders in a motoring mode, and

[0015] - When a compression release mode deactivation demand is received, starting the operation of the second set of the plurality of cylinders in a power mode.

[0016] Accordingly, a method is provided that has conditions for achieving a rapidly decreasing negative crankshaft torque upon receiving a compression release mode deactivation demand. That is, by operating a second set of cylinders among the plurality of cylinders in a motive mode during operation of a first set of cylinders in a compression release mode, a rapid start of the motive mode of the second set of cylinders can be provided upon receiving a compression release mode deactivation demand, so as to rapidly decrease the negative crankshaft torque provided by the first set of cylinders.

[0017] Therefore, due to these features, a method is provided that allows the use of compression release engine braking in a wider range of situations and conditions. Additionally, due to these features, a method is provided that has conditions for facilitating compliance with regulations while avoiding or at least reducing the need for additional auxiliary brakes on the vehicle (such as one or more retarders, etc.).

[0018] Furthermore, since conditions are provided for rapidly decreasing the negative crankshaft torque upon receiving a compression release mode deactivation demand, the method provides conditions for avoiding wheel slip, especially under slippery road conditions. In other words, due to the features of the method, compression release engine braking can also be performed in a safer and more efficient manner in vehicles including driving assistance systems (such as an anti-lock braking system, etc.).

[0019] Moreover, since conditions are provided for rapidly decreasing the negative crankshaft torque upon receiving a compression release mode deactivation demand, an improved vehicle driving feeling as well as faster response and feedback can be provided to the driver, for example when the driver releases the brake pedal or other type of input device to cancel the compression release engine braking.

[0020] Accordingly, a method is provided that overcomes or at least mitigates at least some of the above problems and disadvantages. Thus, the above objectives are achieved.

[0021] Optionally, the method includes the following steps:

[0022] - Upon receiving a compression release mode deactivation demand, initiate deactivation of the compression release mode of the first set of cylinders.

[0023] Thereby, upon receiving a compression release mode deactivation demand, deactivation of the compression release mode of the first set of cylinders and initiation of operation of the motive mode of the second set of cylinders can be initiated simultaneously. Additionally, since the method includes the step of initiating operation of the motive mode of the second set of cylinders among the plurality of cylinders upon receiving a compression release mode deactivation demand, negative torque generated by the first set of cylinders can be compensated during the deactivation phase of the compression release mode of the first set of cylinders.

[0024] Optionally, the method includes the following steps:

[0025] - During the deactivation phase of the compression release mode of the first set of cylinders, operate the second set of cylinders in power mode.

[0026] Thereby, negative crankshaft torque obtained from the first set of cylinders can be compensated during the complete deactivation phase of the compression release mode of the first set of cylinders. In this way, a method is provided that has additional improved conditions allowing the use of compression release engine braking in a wider range of scenarios and conditions. Additionally, a method is provided that has additional improved conditions facilitating compliance with regulations while avoiding or at least reducing the need for additional auxiliary brakes on the vehicle, such as one or more retarders, etc. Further, a method is provided that has additional improved conditions for avoiding wheel slip and for providing an improved vehicle driving feel.

[0027] Optionally, the method includes the steps of:

[0028] - At the end of the deactivation phase of the compression release mode of the first set of cylinders, cancel operating the second set of cylinders in power mode.

[0029] Thereby, conditions are provided for at least substantially neutral crankshaft torque during the time period from when a compression release mode deactivation demand is received until after the end of the deactivation phase of the compression release mode of the first set of cylinders.

[0030] Optionally, the step of operating the second set of cylinders in power mode during the deactivation phase includes the steps of:

[0031] - Control the operation of the second set of cylinders to generate positive crankshaft torque, the magnitude of the positive crankshaft torque being at least 25% or at least 50% of the magnitude of the negative crankshaft torque generated by the first set of cylinders during the deactivation phase.

[0032] Thereby, a significant reduction in the negative crankshaft torque generated by the first set of cylinders during the deactivation phase of the compression release mode can be provided.

[0033] Optionally, the method includes the following steps before the step of operating the first set of cylinders in compression release mode and the step of operating the second set of cylinders in power mode:

[0034] - Estimate the duration of the deactivation phase of the compression release mode, and

[0035] - If the estimated duration exceeds a threshold duration, start operating the first set of cylinders in compression release mode and operating the second set of cylinders in power mode.

[0036] Accordingly, a method is provided, in which if it is determined that a shorter reduction time of the negative crankshaft torque obtained during the compression release engine braking is required when canceling the compression release engine braking, the steps of operating a first set of cylinders in a compression release mode and operating a second set of cylinders in a motoring mode can be performed.

[0037] Optionally, the method may include the steps of performing the following if the estimated duration is shorter than a threshold duration and if a compression release mode start demand is received:

[0038] - Start operating a plurality of cylinders of an internal combustion engine in a compression release mode.

[0039] In this way, if the estimated duration is shorter than the threshold duration and is thus determined to be short enough for obtaining a reduction of the negative crankshaft torque when canceling the compression release engine braking, the compression release engine braking can be performed in all cylinders of the combustion engine.

[0040] Optionally, the step of estimating the duration of the deactivation phase of the compression release mode includes the following steps:

[0041] - Estimate the duration of the deactivation phase of the compression release mode based on data representative of at least one of the following: the current coolant temperature of the combustion engine, the current oil temperature of the combustion engine, the current oil pressure of the combustion engine, the current ambient temperature, the time elapsed since starting the combustion engine, the cumulative fuel flow since starting the combustion engine, the engine revolutions since starting the combustion engine, the distance traveled since starting the combustion engine, and the energy obtained from the combustion engine since starting the combustion engine.

[0042] Accordingly, a reliable estimate of the duration of the deactivation phase of the compression release mode can be provided in a simple and effective manner. This is because each of these types of data can provide a reliable indication of the duration of the deactivation phase of the compression release mode either individually or in combination.

[0043] According to a second aspect of the present invention, the object is achieved by a computer program comprising instructions which, when the program is executed by a computer, cause the computer to perform the method according to some embodiments of the present disclosure. Since the computer program comprises instructions which, when the program is executed by a computer, cause the computer to perform the method according to some embodiments, a computer program is provided which provides the conditions for overcoming or at least alleviating at least some of the above disadvantages. Thus, the above object is achieved.

[0044] According to a third aspect of the present invention, the object is achieved by a computer-readable medium including instructions which, when executed by a computer, cause the computer to perform a method according to some embodiments of the present disclosure. Since the computer-readable medium includes instructions which, when the program is executed by the computer, cause the computer to perform a 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. Thus, the above object is achieved.

[0045] According to a fourth aspect of the present invention, the object is achieved by a control device for an internal combustion engine, the internal combustion engine including a plurality of cylinders, wherein the control device is configured to:

[0046] - operate a first group of cylinders among the plurality of cylinders in a compression release mode,

[0047] - operate a second group of cylinders among the plurality of cylinders in a motoring mode, and

[0048] - upon receiving a compression release mode deactivation demand, initiate operation of the second group of cylinders among the plurality of cylinders in a power mode.

[0049] Thereby, a control device is provided which has conditions for obtaining a rapid reduction of negative crankshaft torque upon receiving a compression release mode deactivation demand. That is, by operating a second group of cylinders among the plurality of cylinders in a motoring mode during operation of the first group of cylinders in a compression release mode, a rapid initiation of the power mode of the second group of cylinders can be provided upon receiving a compression release mode deactivation demand, so as to rapidly reduce the negative crankshaft torque provided by the first group of cylinders.

[0050] Therefore, due to these features, a control device is provided which allows the use of compression release engine braking in a wider range of situations and conditions. In addition, due to these features, a control device is provided which has conditions for facilitating compliance with regulations while avoiding or at least reducing the need for additional auxiliary brakes on the vehicle (such as one or more retarders, etc.).

[0051] Furthermore, since conditions for rapidly reducing negative crankshaft torque upon receiving a compression release mode deactivation demand are provided, the control device provides conditions for avoiding wheel slip, especially under slippery road conditions. In other words, due to the features of the control device, compression release engine braking can also be performed in a safer and more efficient manner in vehicles including a driving assistance system (such as an anti-lock braking system, etc.).

[0052] In addition, since conditions are provided for quickly reducing negative crankshaft torque when a compression release mode deactivation requirement is received, an improved vehicle driving feeling as well as faster response and feedback can be provided to the driver, for example when the driver releases the brake pedal or other type of input device to cancel the compression release engine braking.

[0053] Accordingly, a control device is provided that overcomes or at least mitigates at least some of the above problems and disadvantages. Thus, the above object is achieved.

[0054] It should be understood that the various embodiments described for the method can be combined with the control device as described herein. That is, the control device according to the fourth aspect of the present invention can be configured to perform any of the method steps of the method according to the first aspect of the present invention.

[0055] According to a fifth aspect of the present invention, the object is achieved by an internal combustion engine including a plurality of cylinders and a control device according to some embodiments of the present disclosure. Since the internal combustion engine includes a control device according to some embodiments, an internal combustion engine is provided that overcomes or at least mitigates at least some of the above problems and disadvantages. Thus, the above object is achieved.

[0056] According to a sixth aspect of the present invention, the object is achieved by a vehicle including an internal combustion engine according to some embodiments of the present disclosure. Since the vehicle includes an internal combustion engine according to some embodiments, a vehicle is provided that overcomes or at least mitigates some of the above problems and disadvantages. Thus, the above object is achieved.

[0057] Further features and advantages of the present invention will become apparent when studying the appended claims and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Various aspects of the present invention, including its specific features and advantages, will be readily understood from the following detailed description and the exemplary embodiments discussed in the drawings, wherein:

[0059] Figure 1 A vehicle according to some embodiments is shown,

[0060] Figure 2 is schematically shown Figure 1 the internal combustion engine of the vehicle shown in

[0061] Figure 3 is schematically shown Figure 2 a cross-sectional view of the internal combustion engine shown in

[0062] Figure 4 a method of operating an internal combustion engine is schematically shown

[0063] Figure 5 shows a diagram that displays the moments of some method steps of performing the Figure 4 method shown in, and

[0064] Figure 6 shows a computer-readable medium. DETAILED DESCRIPTION

[0065] Aspects of the present invention will now be described more fully. Like reference numerals always refer to like elements. For brevity and / or clarity, well-known functions or constructions need not be described in detail.

[0066] Figure 1 Vehicle 2 according to some embodiments of the present disclosure is shown. According to the illustrated embodiment, vehicle 2 is a truck, i.e., a type of heavy vehicle. According to additional embodiments, as mentioned herein, vehicle 2 can be another type of heavy or lighter manned or unmanned vehicle for land-based propulsion, such as a van, bus, construction vehicle, tractor, car, etc.

[0067] Vehicle 2 includes an internal combustion engine 1. According to the illustrated embodiment, internal combustion engine 1 is configured to provide motive power to vehicle 2 via wheels 47 of vehicle 2. In addition to internal combustion engine 1, vehicle 2 may also include one or more electric propulsion motors for providing motive power to vehicle 2. Thus, vehicle 2 may include what is referred to as a hybrid electric powertrain that, in addition to internal combustion engine 1, also includes one or more electric propulsion motors for providing motive power to vehicle 2.

[0068] Figure 2 is schematically shown Figure 1 internal combustion engine 1 of vehicle 2 shown. Internal combustion engine 1 includes a plurality of cylinders c1, c2, c3, c4, c5, i.e., includes at least two cylinders c1, c2, c3, c4, c5. In Figure 2 the cylinders c1, c2, c3, c4, c5 of internal combustion engine 1 are schematically indicated. For reasons of brevity and clarity, the reference signs of cylinders c1, c2, c3, c4, c5 of combustion engine 1 are simplified to "c1-c5" in some places herein.

[0069] According to the illustrated embodiment, the internal combustion engine 1 includes five cylinders c1-c5 arranged in a row. Thus, the internal combustion engine 1 according to the illustrated embodiment may be referred to as an in-line five-cylinder engine. However, according to another embodiment, as mentioned herein, the internal combustion engine 1 may include another number of cylinders c1-c5, where the number of cylinders c1-c5 is an integer greater than one. Additionally, the cylinders c1-c5 of the internal combustion engine 1 may be arranged in another configuration different from a row, for example, arranged in two rows or more rows.

[0070] Each cylinder c1-c5 of the internal combustion engine 1 includes at least one fuel injector i1, i2, i3, i4, i5, and the at least one fuel injector is configured to inject fuel into the cylinders c1-c5. For reasons of simplicity and clarity, the reference signs of the fuel injectors i1, i2, i3, i4, i5 of the internal combustion engine 1 are simplified to "i1-i5" in some places herein. According to the illustrated embodiment, the internal combustion engine 1 includes one fuel injector i1-i5 for each cylinder c1-c5, where each fuel injector i1-i5 is configured to directly inject fuel into the cylinders c1-c5 of the internal combustion engine 1. According to another embodiment, the internal combustion engine 1 may include another number of fuel injectors i1-i5 for each cylinder c1-c5.

[0071] According to the illustrated embodiment, the internal combustion engine 1 is a diesel engine, i.e., a type of compression ignition engine. Thus, the internal combustion engine 1 may be configured to operate with diesel or diesel-like fuels (such as biodiesel, biomass-to-liquid (BTL) diesel, or gas-to-liquid (GTL) diesel). Diesel-like fuels (such as biodiesel) can be obtained from renewable resources such as vegetable oils mainly including 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 (soybean methyl ester, SME)).

[0072] According to another embodiment, as mentioned herein, the internal combustion engine 1 may be an Otto engine with a spark ignition device, where the Otto engine may be configured to operate with gasoline, alcohol, similar volatile fuels, or a combination thereof. Alcohol (such as ethanol) can be derived from renewable biomass. According to the embodiments herein, the internal combustion engine 1 is a four-stroke internal combustion engine 1. For reasons of simplicity and clarity, the internal combustion engine 1 is referred to as the "internal combustion engine 1" or simply "engine 1" in some places herein. Additionally, the internal combustion engine 1 mentioned herein may be configured to provide power to another type of unit or system other than a vehicle (such as a generator, etc.).

[0073] Figure 3 is schematically shown Figure 2Cross-sectional view of the internal combustion engine 1 shown. In Figure 3 this, the cross-section is taken in a plane including the central axis of one of the cylinders c1 of the combustion engine 1. In the following, unless otherwise indicated, reference is made simultaneously to Figures 1-3 .

[0074] Each cylinder c1-c5 of the combustion engine 1 includes the same features and functions as the other cylinders c1-c5 of the combustion engine 1. Therefore, Figure 3 it can be said to represent a cross-section of one of the cylinders c1 of the combustion engine 1, where the cylinder c1 can be Figure 2 any one of the cylinders c1-c5 of the combustion engine 1 shown in Figure 3 . However, for reasons of simplicity and clarity, the reference symbol "c1" is mainly used hereinafter to represent

[0075] the cylinder c1 shown in Figure 3 .

[0076] The combustion engine 1 includes a piston 12 arranged in each cylinder c1. The piston 12 is connected to the crankshaft 16 via a connecting rod 13, and the crankshaft, when rotating, causes the piston 12 to move forward and backward in the cylinder c1 between top dead center TDC and bottom dead center BDC. In Figure 3 the piston 12 is shown in the region of top dead center TDC.

[0076] The combustion engine 1 includes an intake system 14, which is shown as an intake duct in the exemplary engine shown. The intake system 14 may also include an air filter and, according to some embodiments, includes a throttle valve, a fuel injector, an air flow sensor, etc. In addition, the combustion engine 1 may include a turbocharger, which is arranged to compress air into the intake system 14 of the combustion engine 1. Therefore, according to such an embodiment, the intake system 14 may be fluidly connected to the compressor of the turbocharger. The compressor may be connected to a shaft, which is connected to the turbine of the turbocharger. The turbine may be arranged to be driven by an air flow from the exhaust outlet 26 of the combustion engine 1. The combustion engine 1 may include more than one turbocharger, where the turbochargers may be arranged in parallel or in series.

[0077] The combustion engine 1 also includes at least one intake valve 18 arranged in each cylinder c1, and the at least one intake valve 18 is connected to the intake system 14. The combustion engine 1 also includes an intake valve control device 22, which is configured to control each intake valve 18 based on the rotational position of the crankshaft 16. The combustion engine 1 also includes at least one exhaust valve 24 arranged in each cylinder c1, and the at least one exhaust valve 24 is connected to the exhaust outlet 26 of the combustion engine 1.

[0078] The combustion engine 1 also includes an exhaust valve control device 28, which is configured to control each exhaust valve 24 based on the rotational position of the crankshaft 16. InFigure 3 In Figure 3 , the intake valve 18 and the exhaust valve 24 are shown in their respective closed positions. In the closed position, each valve 18, 24 abuts against its respective valve seat to close the fluid connection between the cylinder c1 and the corresponding intake system 14 and the exhaust outlet 26.

[0079] The intake valve control device 22 is arranged to control at least one intake valve 18 between the closed position and the open position by displacing at least one intake valve 18 in the direction into the cylinder c1. Thereby, the fluid connection between the intake system 14 and the cylinder c1 is opened. Similarly, the exhaust valve control device 28 is arranged to control at least one exhaust valve 24 between the closed position and the open position by displacing at least one exhaust valve 24 in the direction into the cylinder c1. Thereby, the fluid connection between the cylinder c1 and the exhaust outlet 26 is opened. When the valves 18, 24 are displaced from the closed position to the open position, the valves 18, 24 are lifted from their valve seats.

[0080] The combustion engine 1 further includes a fuel injector 31 which is arranged to inject fuel directly into the cylinder c1. As mentioned above, according to the illustrated embodiment, the combustion engine 1 is a diesel engine, i.e., a type of compression ignition engine. According to a further embodiment, the combustion engine may be an Otto engine with a spark ignition device, where the Otto engine may be designed to operate on gas, gasoline, alcohol or similar volatile fuels or combinations thereof. Such fuel may be injected directly into the cylinder c1 using the fuel injector, or may be supplied to the incoming air before entering the cylinder c1, for example, by a fuel injector arranged at the intake duct of the combustion engine. The combustion engine 1 may include an exhaust aftertreatment system. The exhaust aftertreatment system may include one or more of a catalytic converter, a particulate filter, a selective catalytic reduction (SCR) device, a diesel oxidation catalyst (DOC), a lean NOx trap (LNT) and a three-way catalyst (TWC).

[0081] The exhaust valve control device 28 and the intake valve control device 22 may each include one or more camshafts 71, 72 rotatably connected to the crankshaft 16 of the combustion engine 1. In addition, the exhaust valve control device 28 and the intake valve control device 22 may each include one or more devices (such as rocker arms 73, 74) for transmitting the movement of the cam lobes of the corresponding camshafts 71, 72 to the valve stems of the valves 18, 24 to the open position when the corresponding camshafts 71, 72 rotate. According to a further embodiment, the cam lobes of the camshafts 71, 72 of the combustion engine 1 may be arranged to displace the valves 18, 24 to the open position by pressing on the valve stems of the valves 18, 24 when the corresponding camshafts 71, 72 rotate.

[0082] According to a further embodiment, the exhaust valve control device 28 and / or the intake valve control device 22 may include an electric actuator, a pneumatic actuator or a hydraulic actuator, which are arranged to control the valves based on the rotational position of the crankshaft 16. The rotational position of the crankshaft 16 may be obtained using a crank angle sensor 29.

[0083] According to the illustrated embodiment, the exhaust valve control device 28 includes an exhaust valve phase shift device 30, which is configured to perform phase shift control of at least one exhaust valve 24 relative to the crankshaft 16. Additionally, according to the illustrated embodiment, the intake valve control device 22 includes an intake valve phase shift device 32, which is configured to perform phase shift control of at least one intake valve 18 relative to the crankshaft 16.

[0084] The exhaust valve phase shift device 30 and the intake valve phase shift device 32 may each include a hydraulic device, for example using engine oil as the hydraulic fluid, to perform phase shift control of the valves 18, 24 relative to the crankshaft 16. Such a hydraulic device may form part of a pulley, gear, sprocket, etc. (not shown) of the camshafts 71, 72 arranged to transmit rotation from the crankshaft 16 to the exhaust valve control device 28 and / or the intake valve control device 22. The hydraulic device may be arranged to adjust the angular relationship between a first part of the pulley, gear, sprocket, etc. connected to the crankshaft 16 and a second part of the pulley, gear, sprocket, etc. connected to the camshafts 71, 72, so as to perform phase shift control of at least one intake valve 18 and / or at least one exhaust valve 24. In embodiments where the exhaust valve control device 28 and / or the intake valve control device 22 include an electric actuator, a pneumatic actuator or a hydraulic actuator, phase shift control of at least one intake valve 18 and / or at least one exhaust valve 24 may be performed in another way (e.g., by electronic phase shift control).

[0085] The exhaust valve control device 28 of each cylinder c1 of the combustion engine 1 includes a compression release brake device b1. Figure 2 The compression release brake devices b1 - b5 of all cylinders c1 - c5 of the internal combustion engine 1 are schematically indicated. When the compression release brake devices b1 - b5 are activated, each compression release brake device b1 - b5 is capable of causing an additional valve lift event of at least one exhaust valve 24 of the cylinders c1 - c5. The additional valve lift event may be performed when the pistons 12 of the cylinders c1 - c5 are in the region of top dead center.

[0086] As Figure 3As can be seen, according to the illustrated embodiment, the camshaft 72 of the exhaust valve control device 28 has been provided with an additional cam lobe 72'. According to the illustrated embodiment, the compression release brake device b1 is configured such that when the compression release brake device b1 is deactivated (i.e., not activated), it does not transfer the movement caused by the additional cam lobe 72' to at least one exhaust valve 24. Thus, according to the illustrated embodiment, the compression release brake device b1 is a type of lost motion device. The compression release brake device b1 is configured to transfer the movement caused by the additional cam lobe 72' to at least one exhaust valve 24 when activated. In this way, when the compression release brake device b1 is activated, at least one exhaust valve 24 is opened by the additional cam lobe 72'.

[0087] More specifically, according to the illustrated embodiment, the compression release brake device b1 is of the hydraulic type and includes a hydraulic chamber and at least one valve, wherein the compression release brake device b1 is activated by closing at least one valve and deactivated by opening at least one valve. For reasons of simplicity and clarity, Figure 3 these components are not shown. Additionally, according to the illustrated embodiment, the compression release brake devices b1-b5 of the combustion engine 1 use the engine oil of the combustion engine 1 as the hydraulic fluid. However, according to an alternative embodiment, the combustion engine 1 may include another type of compression release brake device b1 in addition to the hydraulic compression release brake device b1.

[0088] As previously mentioned, when the compression release brake devices b1-b5 are activated, each compression release brake device b1-b5 is capable of causing an additional valve lift event of at least one exhaust valve 24 of the cylinders c1-c5, wherein the additional valve lift event is performed in the region of the top dead center of the pistons 12 of the cylinders c1-c5. In this way, cylinder c1 generates negative crankshaft torque because when the piston 12 is in the region of top dead center TDC, the compressed gas in cylinder c1 during the compression stroke is released into the exhaust outlet 26 of the combustion engine 1. Thus, the energy stored in the compressed gas during the compression stroke will not return to the crankshaft 16 during the subsequent expansion stroke, which increases the negative crankshaft torque generated by cylinder c1.

[0089] The combustion engine 1 includes a control device 21. The control device 21 is operatively connected to each compression release brake device b1-b5 of the combustion engine 1 and is capable of activating and deactivating each compression release brake device b1-b5 of the combustion engine 1.

[0090] In this way, the control device 21 can operate the cylinders c1-c5 in a compression release mode, i.e., a mode in which the compressed gas in cylinder c1 during the compression stroke is released to the exhaust outlet 26 of the internal combustion engine 1. According to the illustrated embodiment, the control device 21 is configured to operate the cylinders in the compression release mode by activating the compression release braking devices b1-b5 of the cylinders c1-c5. Further, according to the illustrated embodiment, the control device 21 is configured to cancel the compression release mode of the cylinders c1-c5 by deactivating the compression release braking devices b1-b5 of the cylinders c1-c5.

[0091] The control device 21 is also operatively connected to each fuel injector i1-i5 of the internal combustion engine 1 and is configured to control the fuel injection into the respective cylinders c1-c5 performed by the fuel injectors i1-i5. The control device 21 may be configured to control the fuel injection amount and the fuel injection timing of each fuel injector i1-i5 of the internal combustion engine 1.

[0092] Obviously, when the cylinders c1-c5 are operating in the compression release mode, no fuel will be injected into the cylinders c1-c5. Thus, according to the embodiments herein, the control device 21 is configured to operate the cylinders c1-c5 in the compression release mode by activating the compression release braking devices b1-b5 of the cylinders c1-c5 and by canceling the fuel injection into the cylinders c1-c5, i.e., such that no fuel is injected into the cylinders c1-c5.

[0093] Further, the control device 21 can operate the cylinders c1-c5 of the internal combustion engine 1 in a coasting mode, i.e., a mode in which no fuel is injected into the cylinders c1-c5. Further, no compression release engine braking is performed in the coasting mode. Thus, as understood from the above, the control device 21 operates the cylinders c1-c5 in the coasting mode by canceling the fuel injection into the cylinders c1-c5 such that no fuel is injected into the cylinders c1-c5 and by ensuring that the compression release braking devices b1-b5 of the cylinders c1-c5 are deactivated.

[0094] As mentioned herein, the coasting mode may also be referred to as a neutral coasting mode in which there is no combustion in the cylinders c1-c5 and which is associated with the normal control of the valves 18, 24 of the cylinders c1-c5. As understood from the above, the coasting mode of the cylinders c1-c5 generates a negative crankshaft torque on the crankshaft 16 of the internal combustion engine 1 because the pistons 12 of the cylinders c1-c5 are forced to reciprocate between the bottom dead center and the top dead center without any combustion during the combustion phase. However, since the energy stored in the compressed gas during the compression stroke is at least partially returned to the crankshaft 16 during the subsequent expansion stroke, the negative crankshaft torque on the crankshaft 16 is lower when the cylinders c1-c5 are operating in the coasting mode compared to when the cylinders c1-c5 are operating in the compression release mode.

[0095] In addition, the control device 21 is capable of operating the cylinders c1-c5 of the combustion engine 1 in a power mode, i.e., a mode in which fuel is injected into the cylinders c1-c5 to generate positive crankshaft torque on the crankshaft 16 of the combustion engine 1 by combustion therein. Obviously, when the cylinders c1-c5 are operated in the power mode, compression release engine braking will not be performed in the cylinders c1-c5. Therefore, the control device 21 is configured to operate the cylinders c1-c5 in the power mode by controlling the fuel injectors i1-i5 to inject fuel into the cylinders c1-c5 while ensuring that the compression release braking devices b1-b5 are deactivated. As mentioned herein, the power mode may also be referred to as a power generation mode, a combustion mode, a power generation combustion mode, etc.

[0096] As used herein, the term "negative crankshaft torque" is intended to encompass a crankshaft torque having such a direction and magnitude that, when transmitted from the crankshaft 16 of the combustion engine 1 to one or more ground engaging wheels 47 of the vehicle 2 via the transmission of the vehicle, causes the vehicle 2 to brake, i.e., decelerate. The direction of the negative crankshaft torque is opposite to the direction of rotation of the crankshaft 16 obtained during operation of the combustion engine 1. Similarly, as used herein, the term "positive crankshaft torque" is intended to encompass a crankshaft torque having such a direction and magnitude that, when transmitted from the crankshaft 16 of the combustion engine 1 to one or more ground engaging wheels 47 of the vehicle 2 via the transmission of the vehicle, causes the vehicle 2 to accelerate in the forward movement direction. The direction of the positive crankshaft torque is consistent with the direction of rotation of the crankshaft 16 obtained during operation of the combustion engine 1.

[0097] As Figure 3 indicated therein, the control device 21 is operatively connected to the control unit 60. The control device 21 is configured to receive a compression release mode activation demand Cba or a compression release mode deactivation demand Cbd from the control unit 60. The compression release mode activation demand Cba indicates a demand to start compression release engine braking, while the compression release mode deactivation demand Cbd indicates a demand to deactivate compression release engine braking.

[0098] The following is explained with reference to Figure 2 and Figure 3 simultaneously. According to an embodiment herein, the control device 21 is configured to operate a first set s1 of cylinders c1-c3 among the plurality of cylinders c1-c5 in a compression release mode, operate a second set s2 of cylinders c4, c5 among the plurality of cylinders c1-c5 in a maneuvering mode, and start operation of the second set s2 of cylinders c4, c5 among the plurality of cylinders c1-c5 in a power mode upon receiving the compression release mode deactivation demand Cbd.

[0099] In this way, when a compression release mode deactivation demand Cbd is received, a rapidly decreasing negative crankshaft torque can be obtained. The rapid decrease of the negative crankshaft torque is advantageous when it is desired to rapidly decrease the negative crankshaft torque obtained during compression release engine braking. As previously mentioned, according to the illustrated embodiment, the compression release braking device b1-b5 of the combustion engine 1 uses the engine oil of the combustion engine 1 as the hydraulic fluid. Therefore, when the engine oil temperature is low, the deactivation time of the compression release braking device b1-b5 is quite long. This is because the viscosity of the engine oil is quite high at low temperatures compared to higher temperatures. Therefore, generally speaking, when the engine oil temperature is low, a longer duration of the deactivation phase of the compression release braking device b1-b5 is obtained.

[0100] However, due to the control of the control device 21 according to the embodiments herein, when a compression release mode deactivation demand Cbd is received, at least a substantially immediate decrease in the negative crankshaft torque can be obtained. The compression release mode deactivation demand Cbd can be received from an actuator (such as a brake pedal, etc.) arranged in the driver environment of the vehicle 2 including the control device 21. As an alternative or in addition, the compression release mode deactivation demand Cbd can be received from another type of system or device of the vehicle 2 including the control device 21 (for example, one or more of a system for operating the vehicle 2 in at least a partially autonomous manner, a cruise control system, a vehicle stability control system, an anti-lock braking system, etc.).

[0101] Similarly, the compression release mode activation demand Cba can be received from an actuator (such as a brake pedal, etc.) arranged in the driver environment of the vehicle 2 including the control device 21. As an alternative or in addition, the compression release mode activation demand Cba can be received from another type of system or device of the vehicle 2 including the control device 21 (for example, one or more of a system for operating the vehicle 2 in at least a partially autonomous manner, a cruise control system, a vehicle stability control system, an anti-lock braking system, etc.).

[0102] In Figure 2 it, the first group s1 of cylinders c1-c3 is shown to include three cylinders c1-c3, while the second group s2 of cylinders is shown to include two cylinders c4, c5. However, according to a further embodiment, the first group s1 of cylinders may include one or more cylinders of the plurality of cylinders c1-c5 of the combustion engine 1, and the second group s2 of cylinders may include one or more cylinders of the plurality of cylinders c1-c5 of the combustion engine 1.

[0103] In addition, according to the illustrated embodiment, the first set s1 of cylinders c1 - c3 plus the second set s2 of cylinders c4, c5 equals the plurality of cylinders c1 - c5 of the combustion engine 1, i.e., equals the total number of cylinders c1 - c5 of the combustion engine 1. However, the sum of the first set s1 of cylinders c1 - c3 and the second set s2 of cylinders c4, c5 may not equal the total number of cylinders c1 - c5 of the combustion engine 1. Further, according to the illustrated embodiment, the cylinders c1 - c3 in the first set s1 of cylinders c1 - c3 are adjacent cylinders c1 - c3, and the cylinders c4, c5 in the second set s2 of cylinders c4, c5 are also adjacent cylinders c4, c5. However, one or both of the first set s1 and the second set s2 among the cylinders c1 - c5 may include non - adjacent cylinders among the plurality of cylinders c1 - c5 of the combustion engine 1.

[0104] The cylinders c1 - c3 in the first set s1 of cylinders c1 - c3 are separate from the cylinders c4, c5 in the second set s2 of cylinders c4, c5, and vice versa. As mentioned herein, the first set s1 of cylinders c1 - c3 may also be referred to as the first part of the cylinders c1 - c3 of the combustion engine 1. Similarly, as mentioned herein, the second set s2 of cylinders c4, c5 may be referred to as the second part of the cylinders c4, c5 of the combustion engine 1, wherein each of the first part and the second part of the cylinders c1 - c5 includes at least one cylinder among the plurality of cylinders c1 - c5 of the combustion engine 1.

[0105] Figure 4 A method 100 for operating an internal combustion engine 1 is schematically illustrated. The internal combustion engine 1 may be the combustion engine 1 according to the embodiments Figures 1-3 illustrated in the reference. Thus, hereinafter, if not otherwise indicated, reference is made simultaneously to Figures 1-4 .

[0106] The method 100 is a method for operating an internal combustion engine 1 that includes a plurality of cylinders c1 - c5,

[0107] wherein the method 100 includes the following steps:

[0108] - Operating 110 the first set s1 of cylinders c1 - c3 among the plurality of cylinders c1 - c5 in a compression - release mode,

[0109] - Operating 120 the second set s2 of cylinders c4, c5 among the plurality of cylinders c1 - c5 in a motoring mode, and

[0110] - Starting 130 the operation of the second set s2 of cylinders c4, c5 among the plurality of cylinders c1 - c5 in a power mode upon receiving a compression - release mode deactivation demand Cbd.

[0111] Figure 5shows a diagram that displays moments of some of the method steps of method 100 shown in Figure 4 . In the following, if not otherwise indicated, reference is made simultaneously to Figures 1-5 . Figure 5 The diagram shown in

[0112] Figure 5 includes a first axis that shows the crankshaft torque cT, -cT supplied to the crankshaft 16 of the combustion engine 1 by cylinders c1 - c5 of the combustion engine 1, and a second axis that shows the time t. Figure 5 As visible in

[0113] before the step of operating 130 the power mode of a second group s2 of cylinders c4, c5 among the plurality of cylinders c1 - c5 in the received compression release mode deactivation demand Cbd, the steps of operating 110 a first group s1 of cylinders c1 - c3 in the compression release mode and operating 120 the second group s2 of cylinders c4, c5 in the motoring mode are performed.

[0114] - estimating 101 the duration of the deactivation phase Dp of the compression release mode, and

[0115] - if the estimated duration exceeds a threshold duration, starting 103 to operate the first group s1 of cylinders c1 - c3 in the compression release mode and the second group s2 of cylinders c4, c5 in the motoring mode.

[0116] In Figure 5 the shown example, the estimated duration exceeds the threshold duration.

[0117] Method 100 may include the step of performing the following if the estimated duration is shorter than the threshold duration and if a compression release mode start demand Cba is received:

[0118] - starting to operate each of the plurality of cylinders c1 - c5 of the internal combustion engine 1 in the compression release mode.

[0119] However, as mentioned before, in Figure 5 the shown example, the estimated duration exceeds the threshold duration, and the step of starting 103 to operate the first group s1 of cylinders c1 - c3 in the compression release mode and the second group s2 of cylinders c4, c5 in the motoring mode is performed by the method shown in Figure 5 .

[0120] The step of estimating the duration of the deactivation phase Dp of the compression release mode 101 may include the following steps:

[0121] - Estimate 102 the duration of the deactivation phase Dp of the compression release mode based on data representative of at least one of the following: the current coolant temperature of the combustion engine 1, the current oil temperature of the combustion engine 1, the current oil pressure of the combustion engine 1, the current ambient temperature, the time elapsed since the start of the combustion engine 1, the cumulative fuel flow since the start of the combustion engine 1, the engine revolutions since the start of the combustion engine 1, the distance traveled since the start of the combustion engine 1, and the energy obtained from the combustion engine since the start of the combustion engine 1.

[0122] In this way, a reliable estimate of the duration of the deactivation phase Dp of the compression release mode can be provided in a simple and reliable manner. This is because each of these types of data can provide a reliable indication of the duration of the deactivation phase Dp of the compression release mode, either individually or in combination.

[0123] Figure 5 The dashed lines indicated by the reference symbol "s1" in the figure indicate the crankshaft torques cT, -cT applied to the crankshaft 16 of the combustion engine 1 by the first group s1 of cylinders c1 - c3 during the time t. Figure 5 The dashed lines indicated by the reference symbol "s2" in the figure indicate the crankshaft torques cT, -cT applied to the crankshaft 16 of the combustion engine 1 by the second group s2 of cylinders c4, c5 during the time t.

[0124] As Figure 5 As can be seen, the step of operating 110 the first group s1 of cylinders c1 - c3 of the plurality of cylinders c1 - c5 in the compression release mode causes the first group s1 of cylinders c1 - c3 to apply a negative crankshaft torque -cT to the crankshaft 16 of the combustion engine 1 during a certain time period that extends from the start 103 of the step of operating the first group s1 of cylinders c1 - c3 in the compression release mode until the time t when a compression release mode deactivation demand Cbd is received. Since the second group s2 of cylinders c4, c5 operate in the motoring mode during this time period, the second group s2 of cylinders c4, c5 apply a small amount of negative crankshaft torque -cT to the crankshaft 16 of the combustion engine 1 during this time period.

[0125] Upon receiving the compression release mode deactivation request Cbd, the step of starting 130 the operation of the power mode of the second group of s2 cylinders c4, c5 causes the second group of s2 cylinders c4, c5 to apply a positive crankshaft torque cT to the crankshaft 16 of the combustion engine 1. Since the second group of s2 cylinders c4, c5 were operated in the motoring mode before the step of starting 130 the operation of the power mode of the second group of s2 cylinders c4, c5, upon receiving the compression release mode deactivation request Cbd, an at least substantially immediate increase in the crankshaft torque cT applied to the crankshaft 16 of the combustion engine 1 can be obtained.

[0126] according to Figure 4 and Figure 5 In the embodiment shown in FIG. 1 , the method 100 includes the following steps:

[0127] - Upon receipt of a compression release mode deactivation request Cbd, deactivation 131 of the compression release mode of the first group s1 of cylinders c1 - c3 is initiated.

[0128] exist Figure 5 , the deactivation phase Dp of the compression release mode of the first group s1 of cylinders c1-c3 is indicated. The deactivation phase Dp of the compression release mode of the first group s1 of cylinders c1-c3 follows the step of starting 131 to deactivate the compression release mode of the first group s1 of cylinders c1-c3. The deactivation phase Dp of the compression release mode of the first group s1 of cylinders c1-c3 may be defined as a phase starting from the step of starting 131 to deactivate the compression release mode and lasting until a 95% reduction in negative crankshaft torque -cT has been obtained. As explained above, the deactivation phase Dp of the compression release mode may be caused by the time required to discharge hydraulic fluid (such as engine oil) from a plurality of compression release brake devices b1-b5 of the combustion engine 1.

[0129] The duration of the deactivation phase Dp of the compression-release mode may, for example, range from 0.2 seconds up to several seconds, depending, for example, on the temperature of the hydraulic fluid used by the compression-release brake devices b1-b5. This duration of the deactivation phase Dp may influence the functionality of driver assistance systems of the vehicle 2, such as an anti-lock braking system (ABS), a system for operating the vehicle 2 in an at least partially autonomous manner, a cruise control system, a vehicle stability control system, etc. Furthermore, this duration may influence the driving feel of the vehicle.

[0130] However, due to the at least substantially immediate increase in crankshaft torque cT obtained by the step of starting 130 operation of the power mode of the second group s2 of cylinders c4, c5, the negative crankshaft torque -cT can be compensated during the deactivation phase Dp of the compression release mode of the first group s1 of cylinders c1-c3.

[0131] according to Figure 4 and Figure 5In the embodiment shown, method 100 includes the following steps:

[0132] - During the deactivation phase Dp of the compression release mode of the first set s1 of cylinders c1 - c3, operate 132 the second set s2 of cylinders c4, c5 in a power mode.

[0133] In addition, according to Figure 4 and Figure 5 In the embodiment shown, the step of operating 132 the second set s2 of cylinders c4, c5 in a power mode during the deactivation phase Dp includes the following steps:

[0134] - Control 134 the operation of the second set s2 of cylinders c4, c5 to generate a positive crankshaft torque cT, the magnitude m1 of which is at least 25%, at least 50%, or at least 75% of the magnitude m2 of the negative crankshaft torque - cT generated by the first set s1 of cylinders c1 - c3 during the deactivation phase Dp.

[0135] According to Figure 5 In the embodiment shown, control the operation of the second set s2 of cylinders c4, c5 to generate a positive crankshaft torque cT, the magnitude m1 of which is approximately 112% of the magnitude m2 of the negative crankshaft torque - cT generated by the first set s1 of cylinders c1 - c3 during the deactivation phase Dp. In this way, the total output torque of the crankshaft 16 of the combustion engine 1 can switch from a negative braking torque to a positive propulsion torque at least substantially immediately upon receiving a compression release mode deactivation demand Cbd. The magnitude m1 of the positive crankshaft torque cT generated by the second set s2 of cylinders c4, c5 can be controlled by controlling the fuel injection quantity and / or the fuel injection timing of the fuel injectors i4, i5 of the second set s2 of cylinders c4, c5.

[0136] Due to the control of the combustion engine 1 according to the embodiments herein, the functions of the vehicle 2's driving assistance systems, such as an anti-lock braking system ABS, a system for operating the vehicle 2 in at least a partially autonomous manner, a cruise control system, a vehicle stability control system, etc., can be significantly improved. In addition, the driving feel of the vehicle can be improved by the control of the combustion engine 1 according to the embodiments herein.

[0137] In addition, due to the control of the combustion engine 1 according to the embodiments herein, it allows the use of compression release engine braking in a wider range of situations and conditions, and facilitates compliance with regulations while avoiding or at least reducing the need for additional auxiliary brakes (such as one or more retarders, etc.) on the vehicle 2.

[0138] In addition, since conditions are provided for quickly reducing the negative crankshaft torque -cT upon receiving the compression release mode deactivation requirement Cbd, conditions are provided for avoiding wheel slip, especially under wet road conditions. In other words, due to these features, the compression release engine brake can also be performed in a safer and more efficient manner in the vehicle 2 including an anti-lock braking system.

[0139] According to Figure 4 and Figure 5 the embodiments shown in, method 100 includes the following steps:

[0140] - At the end of the deactivation phase Dp of the compression release mode of the first set s1 of cylinders c1 - c3, cancel 140 to operate the second set s2 of cylinders c4, c5 in the power mode.

[0141] As Figure 4 indicated, method 100 may include the following steps:

[0142] - At the end of the deactivation phase Dp of the compression release mode of the first set s1 of cylinders c1 - c3, start 141 to operate the first set s1 of cylinders c1 - c3 in the power mode.

[0143] The selection between step 140 and step 141 can be made based on the propulsion requirement, where step 140 can be selected in the case of a neutral maneuver propulsion requirement, and where step 141 can be selected in the case of a positive torque propulsion requirement. The propulsion requirement can be received, for example, from Figure 3 the control unit 60 shown in in the control device 21.

[0144] It should be understood that the various embodiments described for method 100 can all be combined with the control device 21 as described herein. That is, the control device 21 can be configured to perform any one of the method steps 101, 102, 103, 110, 120, 130, 131, 132, 134, 140, and 141 of method 100.

[0145] Figure 6 A computer-readable medium 200 including instructions is shown, which when executed by a computer causes the computer to perform method 100 according to some embodiments of the present disclosure. According to some embodiments, the computer-readable medium 200 includes a computer program, the computer program including instructions which, when the program is executed by the computer, cause the computer to perform method 100 according to some embodiments.

[0146] Those skilled in the art will appreciate that the method 100 of operating the internal combustion engine 1 can be implemented by programming instructions. These programming instructions typically consist of a computer program which, when executed in the control device 21, ensures that the control device 21 performs the desired control, such as the method steps 101, 102, 103, 110, 120, 130, 131, 132, 134, 140 and 141 described herein. The computer program is typically part of a computer program product 200 which includes a suitable digital storage medium having the computer program stored thereon.

[0147] The control device 21 may include a computing unit which may take the form of substantially any suitable type of processor circuit or microcomputer, such as 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 which can interpret and execute instructions. The expression "computing unit" as used herein may denote a processing circuitry system including a plurality of processing circuits, such as any one, some or all of the processing circuits described above.

[0148] The control device 21 may further include a memory unit to which the computing unit may be connected, and which may provide to the computing unit, for example, stored program code and / or stored data that the computing unit may need in order to be able to perform calculations. The computing unit may also be adapted to store partial or final results of the calculations in the memory unit. The memory unit may include physical means for temporarily or permanently storing data or programs (i.e. sequences of instructions). According to some embodiments, the memory unit may include an integrated circuit which includes silicon-based transistors. In different embodiments, the memory unit may include, for example, a memory card, a flash memory, a USB memory, a hard disk or another similar volatile or non-volatile storage unit for storing data, such as, for example, ROM (read-only memory), PROM (programmable read-only memory), EPROM (erasable PROM), EEPROM (electrically erasable PROM), etc.

[0149] The control device 21 is connected to components of the internal combustion engine 1 for receiving and / or transmitting input and output signals. These input and output signals may include waveforms, pulses, or other attributes that can be detected as information by an input signal receiving device and converted into signals that can be processed by the control device 21. These signals can then be supplied to the computing unit. One or more output signal transmitting devices may be arranged to convert the calculation results from the computing unit into output signals for transmission to other parts of the vehicle control system and / or one or more components that the signals are directed to. Each of the connections to the corresponding components of the internal combustion engine 1 for receiving and transmitting input and output signals may take the form of one or more of a data bus from a cable, such as a CAN (Controller Area Network) bus, a MOST (Media Oriented Systems Transport) bus, or some other bus configuration, or a wireless connection.

[0150] In the illustrated embodiment, the internal combustion engine 1 includes the control device 21, but alternatively may be implemented in whole or in part in two or more control devices or two or more control units.

[0151] Control systems in modern vehicles typically include a communication bus system that consists of one or more communication buses for connecting multiple electronic control units (ECUs) or controllers to various components on the vehicle. Such control systems may include a large number of control units, and note that a particular function may be shared between two or more of them. Thus, as will be readily appreciated by those skilled in the art, vehicles and engines of the type addressed herein are typically provided with significantly more control devices than Figure 4 depicted.

[0152] The computer program product 200 may be provided, for example, in the form of a data carrier carrying computer program code for performing at least some of the method steps 101, 102, 103, 110, 120, 130, 131, 132, 134, 140, and 141 according to some embodiments when loaded into one or more computing units of the control device 21. The data carrier may be, for example, a CD ROM disc (as Figure 6 shown), or a ROM (Read Only Memory), PROM (Programmable Read Only Memory), EPROM (Erasable PROM), flash memory, EEPROM (Electrically Erasable PROM), hard disk, memory stick, optical storage device, magnetic storage device, or any other suitable medium that can non-transiently hold machine-readable data, such as a disk or a tape. The computer program product may also be provided as computer program code on a server and may be downloaded remotely to the control device 21, for example, via an Internet or intranet connection or via some other wired or wireless communication system.

[0153] As mentioned herein, the compression release mode deactivation requirement Cbd may also be referred to as the requirement or request to deactivate or cancel the compression release mode of the first set of s1 cylinders c1-c3.

[0154] It should be understood that the foregoing is illustrative of various exemplary embodiments, and the invention is defined only by the appended independent claims. Those skilled in the art will recognize that the exemplary embodiments may be modified without departing from the scope of the invention defined by the appended independent claims, and that different features of the exemplary embodiments may be combined to produce embodiments other than those described herein.

[0155] As used herein, the term "comprising / comprises" is open-ended and includes one or more of the stated features, elements, steps, components or functions, but does not exclude the presence or addition of one or more other features, elements, steps, components, functions or groups thereof.

Claims

1. A method (100) of operating an internal combustion engine (1), the internal combustion engine (1) including a plurality of cylinders (c1 - c5), wherein the method (100) comprises the following steps: - Operating (110) a first group (s1) of cylinders (c1 - c3) among the plurality of cylinders (c1 - c5) in a compression release mode, - Operating (120) a second group (s2) of cylinders (c4, c5) among the plurality of cylinders (c1 - c5) in a motoring mode, and - When receiving a compression release mode deactivation demand (Cbd), starting (130) the operation of the second group (s2) of cylinders (c4, c5) in a power mode.

2. The method (100) according to claim 1, wherein the method (100) comprises the following steps: - When receiving the compression release mode deactivation demand (Cbd), starting (131) to deactivate the compression release mode of the first group (s1) of cylinders (c1 - c3).

3. The method (100) according to claim 2, wherein the method (100) comprises the following steps: - During a deactivation phase (Dp) of the compression release mode of the first group (s1) of cylinders (c1 - c3), operating (132) the second group (s2) of cylinders (c4, c5) in the power mode.

4. The method (100) according to claim 3, wherein the method (100) comprises the following steps: - At the end of the deactivation phase (Dp) of the compression release mode of the first group (s1) of cylinders (c1 - c3), canceling (140) the operation of the second group (s2) of cylinders (c4, c5) in the power mode.

5. The method (100) according to claim 3 or 4, wherein the step of operating (132) the second group (s2) of cylinders (c4, c5) in the power mode during the deactivation phase (Dp) comprises the following steps: - Controlling (134) the operation of the second group (s2) of cylinders (c4, c5) to generate a positive crankshaft torque (cT), the magnitude (m1) of the positive crankshaft torque being at least 25% or at least 50% of the magnitude (m2) of the negative crankshaft torque (-cT) generated by the first group (s1) of cylinders (c1 - c3) during the deactivation phase (Dp).

6. The method (100) according to any one of the preceding claims, wherein the method (100) comprises, before the step of operating (110) the first group (s1) of cylinders (c1 - c3) in the compression release mode and the step of operating (120) the second group (s2) of cylinders (c4, c5) in the motoring mode, the following steps: - Estimating (101) the duration of the deactivation phase (Dp) of the compression release mode, and - If the estimated duration exceeds a threshold duration, starting (103) to operate the first group (s1) of cylinders (c1 - c3) in the compression release mode and operate the second group (s2) of cylinders (c4, c5) in the motoring mode.

7. The method (100) according to claim 6, wherein the step of estimating (101) the duration of the deactivation phase (Dp) of the compression release mode comprises the steps of: - estimating (102) the duration of the deactivation phase (Dp) of the compression release mode based on data representative of at least one of: the current coolant temperature of the combustion engine (1), the current oil temperature of the combustion engine (1), the current oil pressure of the combustion engine (1), the current ambient temperature, the time elapsed since the combustion engine (1) was started, the cumulative fuel flow since the combustion engine (1) was started, the engine revolutions since the combustion engine (1) was started, the distance traveled since the combustion engine (1) was started, and the energy obtained from the combustion engine since the combustion engine (1) was started.

8. A computer program comprising instructions which, when the program is executed by a computer, cause the computer to perform the method (100) according to any one of claims 1 - 7.

9. A computer-readable medium (200) comprising instructions which, when executed by a computer, cause the computer to perform the method (100) according to any one of claims 1 - 7.

10. A control device (21) for an internal combustion engine (1), the internal combustion engine (1) comprising a plurality of cylinders (c1 - c5), wherein the control device (21) is configured to: - operate a first group (s1) of cylinders (c1 - c3) among the plurality of cylinders (c1 - c5) in a compression release mode, - operate a second group (s2) of cylinders (c4, c5) among the plurality of cylinders (c1 - c5) in a motoring mode, and - upon receiving a compression release mode deactivation demand (Cbd), initiate operation of the second group (s2) of cylinders (c4, c5) among the plurality of cylinders (c1 - c5) in a power mode.

11. An internal combustion engine (1) comprising a plurality of cylinders (c1 - c5) and a control device (21) according to claim 10.

12. A vehicle (2) comprising an internal combustion engine (1) according to claim 11.

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