Method of operating an internal combustion engine, computer program, computer-readable medium, control arrangement, and vehicle

Abstract

A method (100) of operating an internal combustion engine (1) of a vehicle (2) is disclosed, wherein the engine (1) comprises one or more combustion chambers (4) and an assembly (41) configured to restrict airflow to the one or more combustion chambers (4) during motoring phases of the engine (1). The method (100) comprises the step of determining 5 (104) whether to operate the engine (1) in a fuel cut allowance mode (AM) or a fuel cut limitation mode (LM) during motoring phases of the engine (1) based on at least one of a current weight estimate (wE) of the vehicle (2) and a current total transmission ratio (tr) between the engine (1) and the driven wheels (27) of the vehicle (2). The present disclosure further relates to a computer program, a computer-readable, a control arrangement (21), and 10 a vehicle (2).

Description

[0001] Method of Operating an Internal Combustion Engine, Computer Program, Computer-Readable Medium, Control Arrangement, and Vehicle

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to a method of operating an internal combustion engine of a vehicle. The present disclosure further relates to a computer program, a computer-readable medium, a control arrangement configured to control operation of an internal combustion engine of a vehicle, as well as a vehicle comprising a control arrangement.

[0004] BACKGROUND

[0005] Internal combustion engines are used to provide motive power to vehicles, commonly via a drivetrain and driven wheels of the vehicle. In many vehicles, the drivetrain comprises a transmission controllable between at least two different gears to provide at least two different transmission ratios between the engine and the driven wheels of the vehicle.

[0006] 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 via a respective connecting rod and normally each comprise one or more piston rings to seal the area between the piston and the cylinder. The pistons are arranged to reciprocate within the cylinders upon rotation of the crankshaft. The crankshaft is commonly arranged in a crankcase of the engine, wherein the crankcase comprises lubricant to lubricate a crankshaft bearing of the crankshaft, bearings between piston rods and the crankshaft, bearings between the pistons and the cylinders, as well as areas between the cylinders and the pistons.

[0007] The engine usually further comprises one or more inlet valves and one or more exhaust valves as well as one or more fuel supply arrangements. The one or more inlet valves and exhaust 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, push rods, or similar. A four-stroke internal combustion engine completes four separate strokes while turning a crankshaft two revolutions. 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, by the ignition device. 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 crankshaft in the expansion stroke.

[0008] 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, because 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. The exhaust stroke is then followed by an inlet stroke.

[0009] General problems when designing an internal combustion engine is the emission levels from the engine as well as the fuel consumption of the engine. Due to environmental concerns, almost all vehicles for sale today comprise some sort of exhaust aftertreatment system. Examples are catalytic converters, particulate filters, and Selective catalytic reduction (SCR) arrangements.

[0010] The conversion efficiency rate of these exhaust aftertreatment systems highly depends on the high temperature of the exhaust gases. Therefore, problems may arise in the converting efficiency of an exhaust aftertreatment system during motoring phases of the engine.

[0011] The term motoring phase refers to a scenario where the crankshaft of the engine is rotated by an external torque. This external torque could derive from the inertia of the vehicle for instance when coasting downhill or slowing down the vehicle with the vehicle in gear and an engine clutch engaged. Normally, no fuel is supplied into the combustion chambers during motoring phases. The pumping of air through the combustion chambers of the engine, and frictional losses within the engine, generates a negative crankshaft torque which in turn generates a braking torque at the driven wheels of the vehicle via the drivetrain of the vehicle.

[0012] Many internal combustion engines comprise an assembly configured to restrict airflow to the one or more combustion chambers during motoring phases of the engine. The airflow to the one or more combustion chambers may for example be restricted during motoring phases of the engine to inhibit the temperature reduction of an exhaust aftertreatment system during the motoring phase. Such an assembly may for example comprises a throttle controllable to restrict airflow to the one or more combustion chambers, and / or a cam phasing assembly configured to phase shift control of inlet valves, and / or exhaust valves, of the engine to restrict airflow to the one or more combustion chambers.

[0013] Another problem that can arise during motoring phases is that the restriction of airflow into the combustion chambers causes an under pressure in the combustion chambers. The under pressure can cause a transport of lubricant past the piston rings into the combustion chambers. When combustion is subsequently initiated, this lubricant is burnt off, resulting in particulate emissions from the engine. Particulate emissions from an engine can be categorised in two different ways, in particle mass and particle number, abbreviated PM and PN respectively. Particulate emissions consist mostly of soot / smoke. Additionally, a transport of lubricant past the piston rings into the combustion chambers of the engine increases the lubricant consumption of the engine.

[0014] One way to mitigate transport of lubricant past the piston rings into the combustion chambers during a motoring phase is to add fuel to the combustion chambers during the motoring phase. The burning of the added fuel increases the pressure in the combustion chambers thereby reversing the pressure balance over the piston rings and reducing the transport of lubricant into the combustion chambers.

[0015] However, the addition of fuel into the combustion chambers can generate a positive crankshaft torque which can reduce the braking torque at the driven wheels of the vehicle, or even produce a positive propulsion torque at the driven wheels. Such a reduction in braking torque, and a generation of a propulsion torque, can be felt by a driver of the vehicle and can reduce the driving experience and the driveability of the vehicle. Likewise, such a reduction in braking torque, or a generation of a propulsion torque, can cause control issues for an at least partially autonomous driving system of the vehicle. That is, if the driver or at least partially autonomous driving system requests a vehicle slowdown, adding fuel to the combustion chambers decreases the rate at which the vehicle decelerates, i.e., its retardation rate.

[0016] In case of a driver of the vehicle is requesting a vehicle slowdown by releasing an accelerator pedal, such a reduction in the rate of slowdown can come unexpectedly to the driver and may give the impression that the vehicle is not responding, and / or does not decelerate as quickly as desired. Moreover, in such situations, the driver might need to apply wheel brakes of the vehicle to achieve a preferred deceleration. Similarly, if an at least partially autonomous driving system initiates a slowdown, the injection of fuel into the combustion chambers might compel the system to utilize other means for slowing down the vehicle, such as wheel brakes of the vehicle.

[0017] Furthermore, the addition of fuel into the combustion chambers during motoring phases may cause drivetrain oscillations. Drivetrain oscillations can result in jerky vehicle operation, significantly diminishing the driving experience. This jerkiness not only makes the ride uncomfortable for vehicle occupants but can also interfere with the ability to control the vehicle smoothly, which affects safety and handling.

[0018] Another way to combat the problem of lubricant transport into combustion chambers during motoring phases could be to implement new hardware solutions or performing a redesign of, and / or structural changes to, various parts of the engine, such as piston ring packages of the engine. However, such solutions normally require extensive testing and evaluation processes which add costs to the final product, and generally, it is an advantage if products, such as combustion engines and vehicles, have conditions and / or characteristics suitable for being produced in a cost-efficient manner.

[0019] SUMMARY

[0020] It is an object of the present invention to overcome, or at least alleviate, at least some of the above-mentioned problems and drawbacks. The object is achieved by the subject-matter of the appended independent claim(s).

[0021] According to a first aspect of the present disclosure, the object is achieved by a method of operating an internal combustion engine of a vehicle, wherein the engine is configured to provide motive power to the vehicle via driven wheels of the vehicle, and wherein the engine comprises one or more combustion chambers and an assembly configured to restrict airflow to the one or more combustion chambers during motoring phases of the engine. The method comprises the step of: - determining whether to operate the engine in a fuel cut allowance mode or a fuel cut limitation mode during motoring phases of the engine based on at least one of a current weight estimate of the vehicle and a current total transmission ratio between the engine and the driven wheels of the vehicle.

[0022] Thereby, a method is provided capable of reducing lubricant transport into combustion chambers of the engine while being capable of avoiding significant reductions in driveability, smoothness of operation, and driving experience of the vehicle. This is because, as realized by the inventors of the present disclosure, each of the current weight of the vehicle and the current total transmission ratio has a significant effect on the negative impacts caused by operation of the engine in the fuel cut limitation mode on driveability, smoothness of operation, and driving experience of the vehicle. Such negative impacts may for example comprise undesired and / or unexpected reductions in vehicle retardation rate, driveline oscillations, jerkiness, and impaired drivability of the vehicle.

[0023] Accordingly, by determining whether to operate the engine in the fuel cut allowance mode or in the fuel cut limitation mode during motoring phases of the engine based on at least one of a current weight estimate of the vehicle and a current total transmission ratio between the engine and the driven wheels of the vehicle, a method is provided capable of efficiently reducing lubricant transport into combustion chambers of the engine, while being capable of ensuring driveability, smoothness of operation, and overall driving experience.

[0024] As a further result, a method is provided capable of reducing particulate emissions from the engine and excessive lubricant consumption, while being capable of ensuring driveability, smoothness of operation, and overall driving experience.

[0025] In addition, a cost efficient method is provided since the method circumvents the need for implementing new hardware solutions and performing redesign and structural changes of various parts of the engine for reducing lubricant transport into combustion chambers of the engine while ensuring driveability, smoothness of operation, and overall driving experience of the vehicle.

[0026] 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. The fuel cut allowance mode, as referred to herein, may be an operation mode for the internal combustion engine in which fuel cut, i.e. , stoppage of fuel supply to the one or more combustion chambers of the internal combustion engine, is allowed.

[0027] Similarly, the fuel cut limitation mode, as referred to herein, may be an operation mode for the internal combustion engine in which fuel cut, i.e., stoppage of fuel supply to the one or more combustion chambers of the internal combustion engine, is limited.

[0028] Optionally, the method comprises the steps of:

[0029] - setting a parameter based on the current weight estimate and the current total transmission ratio,

[0030] - operating the engine in the fuel cut allowance mode during a motoring phase if the parameter is equal to, or below, a threshold value, and

[0031] - operating the engine in the fuel cut limitation mode during a motoring phase of the engine if the parameter is above the threshold value.

[0032] Thereby, a method is provided capable of efficiently reducing lubricant transport into combustion chambers of the engine, while being capable of further ensuring driveability, smoothness of operation, and overall driving experience. This is because the parameter is set based on the current weight estimate and the current total transmission ratio and because the selection between operating the engine in the fuel cut allowance mode or in the fuel cut limitation mode is based on the value of the parameter.

[0033] Optionally, the step of setting the parameter comprises the steps of:

[0034] - setting the parameter based on a ratio between the current weight estimate and the current total transmission ratio.

[0035] Thereby, a method is provided capable of efficiently reducing lubricant transport into combustion chambers of the engine, while being capable of further ensuring driveability, smoothness of operation, and overall driving experience. This is because, as realized by the inventors of the present disclosure, the size of the ratio between the current weight estimate and the current total transmission ratio has a large effect on the negative impacts caused by operation of the engine in the fuel cut limitation mode on driveability, smoothness of operation, and driving experience of the vehicle.

[0036] In more detail, as realized by the inventors of the present disclosure, a small ratio between the current weight estimate and the current total transmission ratio generally leads to larger negative effects by the operation of the engine in the fuel cut limitation mode, as compared to a large ratio between the current weight estimate and the current total transmission ratio, and vice versa.

[0037] Accordingly, by setting the parameter based on the ratio between the current weight estimate and the current total transmission ratio, a method is provided capable of efficiently reducing lubricant transport into combustion chambers of the engine, while being capable of further ensuring driveability, smoothness of operation, and overall driving experience.

[0038] Optionally, the method comprises the step of, during operation in the fuel cut allowance mode:

[0039] - allowing stop of fuel supply to the one or more combustion chambers during a nonrestricted time period.

[0040] Thereby, driveability, smoothness of operation, and overall driving experience can be maintained, for example in case of low current weight estimates of the vehicle and / or high current total transmission ratios between the engine and the driven wheels of the vehicle. Moreover, a low fuel consumption of the internal combustion engine can be ensured for example in case of low current weight estimates of the vehicle and / or high current total transmission ratios between the engine and the driven wheels of the vehicle.

[0041] Optionally, the method comprises the step of,

[0042] - setting the duration of a fuel cut time period, and during operation in the fuel cut limitation mode:

[0043] - stopping fuel supply to the one or more combustion chambers during the fuel cut time period, and

[0044] - initiating fuel supply to the one or more combustion chambers after the fuel cut time period.

[0045] Thereby, an efficient prevention of lubricant transport into combustion chambers of the engine can be further ensured. This is because the method comprises the step of initiating fuel supply to the one or more combustion chambers after the fuel cut time period during operation in the fuel cut limitation mode. Moreover, by stopping fuel supply to the one or more combustion chambers during the fuel cut time period, a relatively low fuel consumption of the internal combustion engine can be ensured.

[0046] Optionally, the step of setting the duration of the fuel cut time period comprises the step of: setting the duration of the fuel cut time period based on a current rotational speed of the engine.

[0047] Thereby, an adaptive method is provided capable of efficiently preventing lubricant transport into combustion chambers of the engine.

[0048] Optionally, the step of setting the duration of the fuel cut time period comprises the steps of:

[0049] - increasing the duration with increasing rotational speeds, and

[0050] - reducing the duration with reducing rotational speeds.

[0051] Thereby, an adaptive method is provided capable of efficiently preventing lubricant transport into combustion chambers of the engine, and minimize the formation of particulate emissions, while ensuring driveability, smoothness of operation, and overall driving experience. This is because, as realized by the inventors of the present disclosure, a fuel supply to the one or more combustion chambers has a higher effect on the formation of particulate emissions from the engine upon lower rotational speeds of the engine as compared to upon higher rotational speeds of the engine.

[0052] Optionally, the step of setting the duration of the fuel cut time period comprises the step of:

[0053] - setting the duration of the fuel cut time period based on the current total transmission ratio.

[0054] Thereby, an adaptive method is provided capable of reducing lubricant transport into combustion chambers of the engine while being capable of avoiding significant reductions in driveability, smoothness of operation, and driving experience of the vehicle.

[0055] Optionally, the step of setting the duration of the fuel cut time period comprises the step of:

[0056] - setting the duration of the fuel cut time period based on the current total transmission ratio such that the duration of the fuel cut time period is increased with reducing total transmission ratios and is reduced with increasing total transmission ratios.

[0057] Thereby, an adaptive method is provided capable of efficiently reducing lubricant transport into combustion chambers of the engine, while providing conditions for ensuring a low fuel consumption of the engine and ensuring maintenance of driveability, smoothness of operation, and overall driving experience. Conditions are provided for ensuring a low fuel consumption of the engine because duration of the fuel cut time period is increased with reducing total transmission ratios. Lower transmission ratios are normally used at relatively higher vehicle speeds, such as during highway driving. As realized by the inventors of the present disclosure, during such driving, problems of lubricant transport into combustion chambers of the engine and formation of particulate emissions are less likely to occur as compared to when operating the engine at higher total transmission ratios, such as during city driving, start-up phases of the vehicle, and the like.

[0058] Accordingly, by setting the duration of the fuel cut time period based on the current total transmission ratio such that the duration of the fuel cut time period is increased with reducing total transmission ratios and is reduced with increasing total transmission ratios, an adaptive method is provided capable of efficiently reducing lubricant transport into combustion chambers of the engine, while providing conditions for maintaining a low fuel consumption of the engine and ensuring maintenance of driveability, smoothness of operation, and overall driving experience.

[0059] Optionally, the method comprises the steps of:

[0060] - setting the duration of a fuel supply time period based on a current rotational speed of the engine, and after the step of initiating fuel supply to the one or more combustion chambers:

[0061] - supplying fuel to the one or more combustion chambers during the fuel supply time period.

[0062] Thereby, it is ensured that lubricant transport into combustion chambers of the engine is efficiently prevented during operation of the internal combustion engine in the fuel cut limitation mode.

[0063] Optionally, the method comprises the step of:

[0064] - stopping fuel supply to the one or more combustion chambers during a second fuel cut time period after the fuel supply time period.

[0065] Thereby, an adaptive method is provided capable of efficiently reducing lubricant transport into combustion chambers of the engine, while providing conditions for maintaining a low fuel consumption of the engine.

[0066] Optionally, the method comprises the step of:

[0067] - setting the duration of the second fuel cut time period based on at least one of the current rotational speed of the engine and the current total transmission ratio. Thereby, an adaptive method is provided capable of efficiently reducing lubricant transport into combustion chambers of the engine, while being capable of ensuring driveability, smoothness of operation, and overall driving experience.

[0068] Optionally, the vehicle comprises a transmission controllable between at least two different gears to provide at least two different transmission ratios between the engine and the driven wheels of the vehicle, and wherein the method comprises the step of:

[0069] - obtaining the current total transmission ratio between the engine and the driven wheels of the vehicle based on a current gear engaged in the transmission.

[0070] Thereby, the current total transmission ratio between the engine and the driven wheels can be obtained in a simple and efficient manner.

[0071] According to a second aspect of the present disclosure, the object is achieved by a computer program comprising instructions to cause the control arrangement according to the second aspect of the present disclosure to execute the steps of the method according to some embodiments of the first aspect of the present disclosure. Since the computer program comprises instructions to cause the control arrangement to carry out the method according to some embodiments described herein, 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.

[0072] According to a third aspect of the present disclosure, the object is achieved by a computer- readable medium having stored thereon the computer program according to the second aspect of the present disclosure. Since the computer-readable medium comprises instructions to cause the control arrangement to carry out the method according to some embodiments described herein, 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.

[0073] According to a fourth aspect of the present disclosure, the object is achieved by a control arrangement configured to control operation of an internal combustion engine of a vehicle, wherein the engine is configured to provide motive power to the vehicle via driven wheels of the vehicle, and wherein the engine comprises one or more combustion chambers and an assembly configured to restrict airflow to the one or more combustion chambers during motoring phases of the engine. The control arrangement is configured to: - determine whether to operate the engine in a fuel cut allowance mode or a fuel cut limitation mode during motoring phases of the engine based on at least one of a current weight estimate of the vehicle and a current total transmission ratio between the engine and the driven wheels of the vehicle.

[0074] Thereby, a control arrangement is provided capable of reducing lubricant transport into combustion chambers of the engine while being capable of avoiding significant reductions in driveability, smoothness of operation, and driving experience of the vehicle. This is because, as realized by the inventors of the present disclosure, each of the current weight of the vehicle and the current total transmission ratio has a significant effect on the negative impacts caused by operation of the engine in the fuel cut limitation mode on driveability, smoothness of operation, and driving experience of the vehicle. Such negative impacts may for example comprise undesired and / or unexpected reductions in vehicle retardation rate, driveline oscillations, jerkiness, and impaired drivability of the vehicle.

[0075] Accordingly, by determining whether to operate the engine in the fuel cut allowance mode or in the fuel cut limitation mode during motoring phases of the engine based on at least one of a current weight estimate of the vehicle and a current total transmission ratio between the engine and the driven wheels of the vehicle, a control arrangement is provided capable of efficiently reducing lubricant transport into combustion chambers of the engine, while being capable of ensuring driveability, smoothness of operation, and overall driving experience.

[0076] As a further result, a control arrangement is provided capable of reducing particulate emissions from the engine and excessive lubricant consumption, while being capable of ensuring driveability, smoothness of operation, and overall driving experience.

[0077] In addition, a cost efficient control arrangement is provided since the control arrangement circumvents the need for implementing new hardware solutions and performing redesign and structural changes of various parts of the engine for reducing lubricant transport into combustion chambers of the engine.

[0078] 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.

[0079] It will be appreciated that the various embodiments described for the method are all combinable with the control arrangement as described herein. That is, the control arrangement according to the fourth aspect of the invention may be configured to perform any one of the method steps of the method according to the first aspect of the invention.

[0080] According to a fifth aspect of the present disclosure, the object is achieved by a vehicle comprising an internal combustion engine configured to provide motive power to the vehicle via driven wheels of the vehicle, wherein the engine comprises one or more combustion chambers and an assembly configured to restrict airflow to the one or more combustion chambers during motoring phases of the engine, and wherein the vehicle comprises a control arrangement according to the fourth aspect of the present disclosure.

[0081] Since the vehicle comprises a control arrangement according to the fourth aspect of the present disclosure, a vehicle is provided in which lubricant transport into combustion chambers of the engine can be efficiently prevented, while being capable of ensuring driveability, smoothness of operation, and overall driving experience of the vehicle.

[0082] 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.

[0083] Optionally, the engine is a spark ignition engine. Thereby, a vehicle is provided comprising a spark ignition engine in which lubricant transport into combustion chambers of the engine can be efficiently prevented, while being capable of ensuring driveability, smoothness of operation, and overall driving experience of the vehicle.

[0084] Optionally, the vehicle is a heavy road vehicle, such as a truck or a bus. Thereby, a heavy road vehicle is provided having at least some of the above-mentioned advantages.

[0085] Further features of, and advantages with, the present invention will become apparent when studying the appended claims and the following detailed description.

[0086] BRIEF DESCRIPTION OF THE DRAWINGS

[0087] Various aspects of the present disclosure, including its particular features and advantages, will be readily understood from the example embodiments discussed in the following detailed description and the accompanying drawings, in which:

[0088] Fig. 1 schematically illustrates a vehicle according to some embodiments, Fig. 2 illustrates a cross sectional view of an internal combustion engine of the vehicle illustrated in Fig. 1,

[0089] Fig. 3 illustrates an upper graph showing a fuel injection rate into one or more combustion chambers of the engine illustrated in Fig. 1 and Fig. 2 as a function of time during operation in a fuel cut allowance mode of the engine and a lower graph showing a fuel injection rate into the one or more combustion chambers of the engine illustrated in Fig. 1 and Fig. 2 as a function of time during operation in a fuel cut limitation mode of the engine,

[0090] Fig. 4 schematically illustrates a method of operating an internal combustion engine of a vehicle, and

[0091] Fig. 5 illustrates a computer-readable medium.

[0092] DETAILED DESCRIPTION

[0093] Aspects of the present disclosure will now be described more fully. Like reference signs refer to like elements throughout. Well-known functions or constructions will not necessarily be described in detail for brevity and / or clarity.

[0094] Fig. 1 schematically illustrates a vehicle 2 according to some embodiments. According to the illustrated embodiments, the vehicle 2 is a truck, i.e. , a type of heavy road vehicle, as well as a type of heavy commercial vehicle. According to further embodiments, the vehicle 2, as referred to herein, may be another type of heavy or lighter type of manned or unmanned vehicle for land-based propulsion such as a lorry, a bus, a construction vehicle, a tractor, a car, or the like.

[0095] The vehicle 2 comprises a transmission 3 and an internal combustion engine 1. The internal combustion engine 1 is operably connected to driven wheels 27 of the vehicle 2 via the transmission 3. In other words, the internal combustion engine 1 is configured to provide motive power to the vehicle 2 via the transmission 3 and the driven wheels 27 of the vehicle 2.

[0096] According to the illustrated embodiments, the vehicle 2 comprises two driven wheels 27 which constitute rear-wheels of the vehicle 2. The vehicle 2 further comprises two non-driven wheels 27’, which according to the illustrated embodiments constitute front-wheels of the vehicle 2. However, according to further embodiments, the vehicle 2 may comprise another configuration of driven and non-driven wheels.

[0097] The transmission 3 is controllable between at least two different gears to provide at least two different transmission ratios between the internal combustion engine 1 and the driven wheels 27 of the vehicle 2. The at least two different transmission ratios may also be referred to as at least two different gear steps or at least two different gear ratios. The transmission 3, as referred to herein, may also be referred to as a gearbox. A transmission ratio between the internal combustion engine 1 and the driven wheels 27 of the vehicle 2, as referred to herein, may be equated with a transmission ratio between an output shaft of the internal combustion engine 1 and the driven wheels 27 of the vehicle 2.

[0098] The transmission 3 may be an automated manual transmission, usually abbreviated AMT. An automated manual transmission combines the efficiency of a manual transmission with the convenience of an automatic transmission. Contrary to traditional automatic transmissions that employ torque converters and planetary gearsets, an automated manual transmission features a gearbox with a gear layout, and a mechanical gear engagement and disengagement process, similar to that of a manual transmission.

[0099] Moreover, an automated manual transmission may comprise a clutch controllable to disengage an input shaft of the gearbox from an output shaft of the internal combustion engine 1. The automated manual transmission may further comprise a number of actuators controllable to execute clutch movements of the clutch and gear shifts via gear shifting linkages, thereby removing the need for the driver to manually operate a clutch pedal or gear lever.

[0100] Moreover, according to some embodiments, the transmission 3, as referred to herein, may be an automatic transmission of conventional type, commonly abbreviated as AT, which comprises a torque converter and planetary gearsets. The torque converter in such an automatic transmission serves as a fluid coupling that replaces the clutch, allowing the internal combustion engine 1 to stay running while the vehicle is stationary. The torque converter also provides the ability to multiply torque under acceleration. The planetary gearsets commonly comprises a central sun gear, planet gears that revolve around the sun gear, and a ring gear that encompasses the planet gears, to offer a range of selectable gears. Moreover, this type of automatic transmission is normally equipped with a hydraulic control system that manages the operation of the torque converter and the engagement of the planetary gearsets.

[0101] According to the illustrated embodiments, the vehicle 2 comprises the internal combustion engine 1 as the only power source for providing motive power to the vehicle 2. However, according to further embodiments, the vehicle 2 may comprise one or more electric propulsion machines for providing motive power to the vehicle 2 in addition to the internal combustion engine 1. According to such embodiments, the vehicle 2 may also be referred to as a hybrid electric vehicle.

[0102] The vehicle 2 further comprises a control arrangement 21. According to the illustrated embodiments, the control arrangement 21 is operably connected to the internal combustion engine 1 and to the transmission 3.

[0103] In Fig. 1, a forward moving direction fd and a reverse moving direction rd of the vehicle 2 are indicated. The reverse moving direction rd is opposite to the forward moving direction fd of the vehicle 2. Each of the forward and reverse moving directions fd, rd is parallel to a longitudinal direction Id of the vehicle 2.

[0104] Fig. 2 illustrates a cross sectional view of the internal combustion engine 1 of the vehicle 2 illustrated in Fig. 1. For the reason of brevity and clarity, the internal combustion engine 1 is in some places herein referred to as “the combustion engine”, or simply “the engine 1”. Below, simultaneous reference is made to Fig. 1 and Fig. 2, if not indicated otherwise.

[0105] The engine 1 comprises one or more combustion chambers 4 each delimited by a cylinder 10 and a piston 12 arranged the cylinder 10. In Fig. 2, only one cylinder 10 of the engine 1 is seen and consequently also only one combustion chamber 4 and one piston 12. However, the engine 1 may comprise more than one cylinder 10 each delimiting a combustion chamber 4 together with a piston 12 arranged in the cylinder 10. The engine 1 may for example comprise four, six, or eight cylinders 10.

[0106] The engine 1 comprises a crankcase delimiting a crank case volume V. The crankcase of the engine 1 is not illustrated in Fig. 2 for reasons of brevity and clarity. The engine 1 further comprises a crankshaft 16. The crankshaft 16 is at least partially arranged in the crankcase volume V. Each piston 12 of the engine 1 is connected to the crankshaft 16 via a respective connecting rod 13.

[0107] The pistons 12 move forwards and backwards in the respective cylinder 10 between a top dead centre and a bottom dead centre upon rotation of the crankshaft 16. The engine 1 comprises an air inlet 14, which in the illustrated example engine is illustrated as an inlet duct. Moreover, the engine 1 comprises an air filter unit 47 configured to filtrate air flowing into the air inlet 14. According to the illustrated embodiments, the engine 1 is a four-stroke internal combustion engine 1 which comprises at least one inlet valve 18 arranged in each cylinder 10, which at least one inlet valve 18 is connected with the air inlet 14. The engine 1 further comprises an inlet valve control arrangement 22 configured to control each inlet valve 18 on the basis of a rotational position of the crankshaft 16. The engine 1 further comprises at least one exhaust valve 24 arranged in each cylinder 10, which at least one exhaust valve 24 is connected with an exhaust outlet 26 of the engine 1.

[0108] The engine 1 further comprises an exhaust valve control arrangement 28 configured to control each exhaust valve 24 on the basis of the rotational position of the crankshaft 16. In Fig. 2, the at least one inlet valve 18 and the at least one exhaust valve 24 are illustrated in a respective closed position. In the closed position, each valve 18, 24 abuts against a respective valve seat to close fluid connection between the combustion chamber 4 and the respective air inlet 14 and the exhaust outlet 26 respectively.

[0109] The inlet valve control arrangement 22 is arranged to control the at least one inlet valve 18 between the closed position and an open position by displacing the at least one inlet valve 18 in a direction into the cylinder 10. A fluid connection is thereby opened between the air inlet 14 and the combustion chamber 4. Likewise, the exhaust valve control arrangement 28 is arranged to control the at least one exhaust valve 24 between the closed position and an open position by displacing the at least one exhaust valve 24 in a direction into the cylinder 10. Thereby, a fluid connection is opened between the combustion chamber 4 and the exhaust outlet 26. Upon displacement of a valve 18, 24 from the closed position to the open position, the valve 18, 24 is lifted from its valve seat.

[0110] The exhaust valve control arrangement 28 and the inlet valve control arrangement 22 may each comprise one or more camshafts rotatably connected to the crankshaft 16, wherein the camshafts comprises cam lobes arranged to displace valves 18, 24 to an open position by pressing on valve stems of the valves 18, 24 upon rotation of the camshaft. The exhaust valve control arrangement 28 and / or the inlet valve control arrangement 22 may according to further embodiments comprise electric, pneumatic, or hydraulic actuators arranged to control valves on the basis of the rotational position of the crankshaft 16. The rotational position of the crankshaft 16 may be obtained using data from a crank angle sensor 29.

[0111] According to the illustrated embodiments, the engine 1 is a spark ignition engine, i.e. , an Otto engine with a spark-ignition device 34. According to the illustrated embodiments, the spark- ignition device 34 is a spark plug. The spark-ignition device 34 is configured to ignite an air fuel mixture in the combustion chamber 4.

[0112] The engine 1 may be configured to run on petrol, alcohol, a gaseous fuel, or combinations thereof. Alcohol, such as ethanol, can be derived from renewable biomass. The gaseous fuel may also be referred to as fuel gas and may encompass any type of fuel that under ordinary ambient temperature and pressure conditions are gaseous and which can be stored at pressure in a pressure tank and can be combusted in an internal combustion engine 1 to produce useful work. Examples of such gaseous fuels are compressed natural gas (CNG), liquified natural gas (LNG), Liquefied Petroleum Gas (LPG), Hydrogen (H2), Biogas, and Syngas. Many gaseous fuels can be derived from renewable sources, such as from renewable biomass.

[0113] According to further embodiments, internal combustion engine 1, as referred to herein, may be a compression ignition engine, such as a diesel engine. The internal combustion engine 1 may thus be configured to operate on diesel or a diesel-like fuel, such as biodiesel, biomass to liquid (BTL), or gas to liquid (GTL) diesel. Diesel-like fuels, such as biodiesel, can be obtained from renewable sources such as vegetable oil which mainly comprises fatty acid methyl esters (FAME). Diesel-like fuels can be produced from many types of oils, such as rapeseed oil (rapeseed methyl ester, RME) and soybean oil (soy methyl ester, SME). Moreover, the internal combustion engine 1, as referred to herein, may be a duel-fuel engine configured to operate on two different fuels, such as a gaseous fuel and a liquid fuel.

[0114] The engine 1 further comprises a fuel supply arrangement 6. The fuel supply arrangement 6 is configured to supply fuel to the one or more combustion chambers 4 of the engine 1. In Fig. 2, the fuel supply arrangement 6 is depicted as a fuel injector configured to inject a fuel into the air inlet 14 of the engine 1. However, as an alternative, or in addition, the fuel supply arrangement 6 of the engine 1 may comprise one or more other types of fuel supply devices, such as one or more fuel injectors configured to inject fuel directly into combustion chambers 4 of the engine 1. As seen in Fig. 2, the control arrangement 21 of the engine 1 is operably connected to the fuel supply arrangement 6.

[0115] As is further explained in the following, the engine 1 comprises an assembly 41 configured to restrict airflow to the one or more combustion chambers 4 during motoring phases of the engine 1. The assembly 41 may also be referred to as an inlet air flow control assembly, an inlet air flow restriction assembly, or the like. According to the embodiments depicted in Fig. 2, the assembly 41 comprises a throttle 5 and an actuator 30, wherein the actuator 30 is configured to control the position of the throttle 5. The throttle 5 is controllable by the actuator 30 between an open position and an at least partially closed position. In Fig. 1 , the throttle 5 is schematically depicted in a partially closed position in which the throttle 5 restricts airflow to the one or more combustion chambers 4 of the engine 1.

[0116] Moreover, according to the embodiments depicted in Fig. 2, the assembly 41 further comprises an inlet valve phase-shifting device 31 and an exhaust valve phase-shifting device 32. The inlet valve phase-shifting device 31 is controllable to restrict airflow to the one or more combustion chambers 4 by phase-shifting control of the at least one inlet valve 18 in relation to the crankshaft 16. Likewise, the exhaust valve phase-shifting device 32 is controllable to restrict airflow to the one or more combustion chambers 4 by phase-shifting control of the at least one exhaust valve 24 in relation to the crankshaft 16.

[0117] The inlet valve phase-shifting device 31 and the exhaust valve phase-shifting device 32 may each comprise a hydraulic arrangement, for example using engine oil as hydraulic fluid, to phase-shift control of the valves 18, 24 in relation to the crankshaft 16. Such hydraulic arrangement may form part of a belt pulley (not illustrated) arranged to transfer rotation from the crankshaft 16 to a camshaft of the exhaust valve control arrangement 28 and / or the inlet valve control arrangement 22, wherein the hydraulic arrangement is arranged to regulate an angular relationship between a first portion of the belt pulley, being connected to the crankshaft 16, and a second portion of the belt pulley, being connected to the camshaft, in order to phase-shift control of the at least one inlet valve 18 and / or the at least one exhaust valve 24.

[0118] In embodiments wherein the exhaust valve control arrangement 28 and / or the inlet valve control arrangement 22 comprises electric, pneumatic, or hydraulic actuators, the exhaust valve phase-shifting device 32 and / or the inlet valve phase-shifting device 31 may phaseshift control of the at least one valve 18, 24 in another manner, for example by an electronic phase-shift of control.

[0119] According to the embodiments illustrated in Fig. 2, the control arrangement 21 of the engine 1 is operably connected to the assembly 41 by being operably connected to each of the actuator 30 of the throttle 5, the inlet valve phase-shifting device 31 and the exhaust valve phase-shifting device 32. However, according to further embodiments, the assembly 41, as referred to herein may comprise only one or two of the actuator 30 of the throttle 5, the inlet valve phase-shifting device 31 and the exhaust valve phase-shifting device 32 explained above. In such embodiments, the control arrangement 21 may only be operably connected to such parts of the assembly 41.

[0120] As mentioned, the assembly 41 is configured to restrict airflow to the one or more combustion chambers 4 during motoring phases of the engine 1. The term motoring phase, as used herein, refers to a scenario where the crankshaft 16 of the engine 1 is rotated by an external torque.

[0121] This external torque could derive from the inertia of the vehicle 2 for instance when coasting downhill or slowing down the vehicle 2 with a gear engaged in the transmission 3 and an engine clutch engaged. Normally, no fuel is supplied into the combustion chambers 4 during motoring phases. The pumping of air through the combustion chambers 4 of the engine 1, and frictional losses within the engine 1 , generates a negative crankshaft torque which in turn generates a braking torque at the driven wheels 27 of the vehicle 2 via the drivetrain of the vehicle 2.

[0122] According to embodiments herein, the control arrangement 21 is configured to obtain a current weight estimate wE of the vehicle 2, i.e., an estimate of a current weight of the vehicle 2. According to some embodiments, the control arrangement 21 may be configured to obtain the current weight estimate wE from an input unit arranged in a driver environment of the vehicle 2, from an external senser, or the like.

[0123] As an alternative, or in addition, the control arrangement 21 may be configured to obtain the current weight estimate wE of the vehicle 2 by estimating the current weight estimate wE based on data from a number of onboard sensors, i.e., sensors arranged on the vehicle 2. Such number of sensors may comprise one or more of an inclinometer, and / or gyroscope, configured to provide data representative of a current orientation of the vehicle 2 relative to the local gravitational field, an accelerometer configured to measure a current acceleration of the vehicle 2, a vehicle speed sensor configured to monitor a current speed of the vehicle 2, one or more sensors configured to measure data indicative of a current power output of the internal combustion engine 1, such as current output torque and current rotational speed of the internal combustion engine 1, one or more load sensors configured to provide data representative of a current weight of cargo loaded into the vehicle 2, one or more strain gauge sensors configured to provide data of relative positions of parts of a suspension assembly of the vehicle 2, and a number of tire pressure monitoring sensors. According to the embodiments illustrated in Fig. 1, the vehicle 2 comprises a coupling assembly 51 for coupling a trailer to the vehicle 2. The trailer is not illustrated in Fig. 1 for reasons of brevity and clarity. The coupling assembly 51 may be a fifth wheel coupling assembly. The vehicle 2, as referred to herein, may comprise the trailer. In other words, the vehicle 2, as referred to herein, may comprise the vehicle 2 depicted in Fig. 1 and a trailer connected to the vehicle 2 depicted in Fig. 1 via the coupling assembly 51 of the vehicle 2. In other words, according to embodiments herein, the vehicle 2 may be a vehicle combination comprising a towing vehicle with a trailer articulately connected to the vehicle 2.

[0124] According to some embodiments, the trailer comprises a number of load sensors configured to provide data representative of a current weight of cargo loaded into the trailer, wherein the control arrangement 21 is configured to receive data from the number of load sensors via a signal cable extending between the towing vehicle and the trailer. According to such embodiments, the control arrangement 21 may be configured to obtain the current weight estimate wE of the vehicle based on data from the number of load sensors of the trailer.

[0125] Moreover, according to embodiments herein, the control arrangement 21 is configured to obtain a current total transmission ratio tr between the engine 1 and the driven wheels 27 of the vehicle 2. The current total transmission ratio tr, as referred to herein, means a total transmission ratio, also known as a gear ratio, between the crankshaft 16 of the internal combustion engine 1 and the driven wheels 27 of the vehicle 2.

[0126] As mentioned, according to the illustrated embodiments, the transmission 3 is controllable between at least two different gears to provide at least two different transmission ratios between the engine 1, i.e., the crankshaft 16 of the engine 1, and the driven wheels 27 of the vehicle 2. According to these embodiments, the control arrangement 21 is configured to obtain the current total transmission ratio tr between the engine 1 and the driven wheels 27 of the vehicle 2 based on a current gear engaged in the transmission 3. Moreover, the control arrangement 21 may calculate the current total transmission ratio tr between the engine 1 and the driven wheels 27 of the vehicle 2 utilizing the transmission ratio provided by the current gear engaged in the transmission 3 and a factor, constant, or variable representative of the total transmission ratio provided by the remaining parts of the driveline of the vehicle 2. Such remaining parts may include intermediate gearing, reduction gearing, differential gearing, rolling radius of the driven wheels 27, and the like.

[0127] Furthermore, according to the illustrated embodiments, the control arrangement 21 is configured to control the assembly 41 to restrict airflow to the one or more combustion chambers 4 of the engine 1 during motoring phases of the engine 1. The control arrangement 21 may be configured to control the assembly 41 to restrict airflow to the one or more combustion chambers 4 by controlling the actuator 30 of the throttle 5 to move the throttle 5 to an at least partially closed position. As an alternative, or in addition, the control arrangement 21 may be configured to control the assembly 41 to restrict airflow to the one or more combustion chambers 4 by controlling the inlet valve phase-shifting device 31, and / or the exhaust valve phase-shifting device 32, to phase-shift control of the inlet / exhaust valves 18, 24 in relation to the crankshaft 16.

[0128] The control arrangement 21 may be configured to input an engine motoring demand, and / or a vehicle deceleration demand, and may in response thereto control the assembly 41 to restrict airflow to the one or more combustion chambers 4 of the engine 1. The engine motoring demand, and / or a vehicle deceleration demand, may be inputted from an actuator arranged in a driver environment 55 of the vehicle 2, such as an accelerator pedal, brake pedal or the like. As an alternative, or in addition, the engine motoring demand, and / or a vehicle deceleration demand, may be inputted from an at least partially autonomous driving system of the vehicle 2, from a communication device, or from another type of device or system of the vehicle 2.

[0129] The at least partially autonomous driving system, as referred to herein, may be configured to control the speed of the vehicle 2, and / or steering of the vehicle 2, based on data from a sensor assembly of the vehicle 2. The at least partially autonomous driving system 2 may be a fully or partly autonomous driving system capable of driving the vehicle 2 in an at least partially autonomous manner based on the input from the sensor assembly. Moreover, the at least partially autonomous driving system, as referred to herein, may be a cruise control system, an adaptive cruise control system, a semi-autonomous driving system, or a fully autonomous driving system.

[0130] Fig. 3 illustrates an upper graph showing a fuel injection rate iF into the one or more combustion chambers 4 of the engine 1 illustrated in Fig. 1 and Fig. 2 as a function of time t during operation in a fuel cut allowance mode AM of the engine 1 and a lower graph showing a fuel injection rate iF into the one or more combustion chambers 4 of the engine 1 illustrated in Fig. 1 and Fig. 2 as a function of time t during operation in a fuel cut limitation mode LM of the engine 1.

[0131] Below, simultaneous reference is made to Fig. 1 - Fig. 3, if not indicated otherwise. In more detail, the upper graph of Fig. 3 comprises a horizontal axis showing time t and a vertical fuel injection rate iF into the one or more combustion chambers 4 of the engine 1 during operation of the engine 1 in the fuel cut allowance mode AM. Likewise, the lower graph of Fig. 3 comprises a horizontal axis showing time t and a vertical axis showing fuel injection rate iF into the one or more combustion chambers 4 of the engine 1 during operation of the engine 1 in the fuel cut limitation mode LM.

[0132] Fig. 4 schematically illustrates a method 100 of operating an internal combustion engine 1 of a vehicle 2. The internal combustion engine may be an internal combustion engine 1 according to the embodiments explained with reference to Fig. 1 - Fig. 3. Likewise, the vehicle may be a vehicle 2 according to the embodiments illustrated in Fig. 1. Moreover, some of the method steps 101, 10T, 102, 103, 104, 105, 106, 108, 110, 111, 112, 113, 115, 117, 120, 122, 124, 130, 140, 142, 150, 160, and 162 of the method 100 illustrated in Fig. 4 are also depicted in Fig. 3. Therefore, below, simultaneous reference is made to Fig. 1 - Fig. 4, if not indicated otherwise.

[0133] As is further explained in the following, the control arrangement 21 of the engine 1 may be configured to perform any one of the method steps 101 , 10T, 102, 103, 104, 105, 106, 108, 110, 111, 112, 113, 115, 117, 120, 122, 124, 130, 140, 142, 150, 160, and 162 of the method 100 illustrated in Fig. 4.

[0134] The method 100 is a method of operating an internal combustion engine 1 of a vehicle 2, wherein the engine 1 is configured to provide motive power to the vehicle 2 via driven wheels 27 of the vehicle 2, and wherein the engine 1 comprises one or more combustion chambers 4 and an assembly 41 configured to restrict airflow to the one or more combustion chambers 4 during motoring phases of the engine 1. The method 100 comprises the step of:

[0135] - determining 104 whether to operate the engine 1 in a fuel cut allowance mode AM or a fuel cut limitation mode LM during motoring phases of the engine 1 based on at least one of a current weight estimate wE of the vehicle 2 and a current total transmission ratio tr between the engine 1 and the driven wheels 27 of the vehicle 2

[0136] In other words, according to embodiments herein, the control arrangement 21 is configured to determine whether to operate the engine 1 in the fuel cut allowance mode AM or the fuel cut limitation mode LM during motoring phases of the engine 1 based on at least one of a current weight estimate wE of the vehicle 2 and a current total transmission ratio tr between the engine 1 and the driven wheels 27 of the vehicle 2. In this manner, lubricant transport from the crankcase volume V into combustion chambers 4 of the engine 1 can be efficiently prevented, while being capable of ensuring driveability, smoothness of operation, and overall driving experience of the vehicle 2, as is further explained herein.

[0137] As mentioned, according to the illustrated embodiments, the vehicle 2 comprises a transmission 3 controllable between at least two different gears to provide at least two different transmission ratios between the engine 1 and the driven wheels 27 of the vehicle 2. As indicated in Fig. 3 and Fig. 4, according to these embodiments, the method 100 comprises the step of: obtaining 101 the current total transmission ratio tr between the engine 1 and the driven wheels 27 of the vehicle 2 based on a current gear engaged in the transmission 3.

[0138] The step of obtaining 101 the current total transmission ratio tr between the engine 1 and the driven wheels 27 of the vehicle 2 may be based on a calculation utilizing the transmission ratio provided by the current gear engaged in the transmission 3 and a factor, constant, or variable representative of the total transmission ratio provided by the remaining parts of the driveline of the vehicle 2. Such remaining parts may include intermediate gearing, reduction gearing, differential gearing, rolling radius of the driven wheels 27, and the like.

[0139] Moreover, as indicated in Fig. 3 and Fig. 4, according to the illustrated embodiments, the method comprises the step of: obtaining 10T the current weight estimate wE of the vehicle 2.

[0140] The step obtaining 10T the current weight estimate wE of the vehicle 2 may utilize one or more of the means for obtaining the current weight estimate wE explained with reference to Fig. 1 and Fig. 2 above.

[0141] Obviously, the steps of obtaining 101 the current total transmission ratio tr and obtaining 10T the current weight estimate wE may be performed prior to the step of determining 104 whether to operate the engine 1 in a fuel cut allowance mode AM or a fuel cut limitation mode LM during motoring phases of the engine 1.

[0142] According to some embodiments, the method 100 comprises the step of: restricting airflow to the one or more combustion chambers 4 of the engine 1 during motoring phases of the engine 1. The step of restricting airflow to the one or more combustion chambers 4 of the engine 1 may be performed by controlling operation of the assembly 41. As mentioned, according to the illustrated embodiments, the assembly 41 comprises a throttle 5 and an actuator 30.

[0143] According to these embodiments, the step of restricting airflow to the one or more combustion chambers 4 of the engine 1 may be performed by controlling the throttle 5 to an at least partially closed position. As understood from the above described, in these embodiments, the throttle 5 may be controlled to an at least partially closed position by controlling operation of the actuator 30.

[0144] Moreover, according to the illustrated embodiments, the assembly 41 further comprises an inlet valve phase-shifting device 31 and an exhaust valve phase-shifting device 32.

[0145] According to these embodiments, the step of restricting airflow to the one or more combustion chambers 4 of the engine 1 may be performed by controlling the inlet valve phase-shifting device 31, and / or the exhaust valve phase-shifting device 32, to phase-shift control of the inlet / exhaust valves 18, 24 in relation to the crankshaft 16.

[0146] Furthermore, as indicated in Fig. 3 and Fig. 4, according to the illustrated embodiments, the method comprises the steps of:

[0147] - setting 102 a parameter p based on the current weight estimate wE and the current total transmission ratio tr,

[0148] - operating 105 the engine 1 in the fuel cut allowance mode AM during a motoring phase if the parameter p is equal to, or below, a threshold value th, and

[0149] - operating 106 the engine 1 in the fuel cut limitation mode LM during a motoring phase of the engine 1 if the parameter p is above the threshold value th.

[0150] In other words, according to the illustrated embodiments, the control arrangement 21 is configured to:

[0151] - set the parameter p based on the current weight estimate wE and the current total transmission ratio tr,

[0152] - operate the engine 1 in the fuel cut allowance mode AM during a motoring phase if the parameter p is equal to, or below, a threshold value th, and

[0153] - operate the engine 1 in the fuel cut limitation mode LM during a motoring phase of the engine 1 if the parameter p is above the threshold value th.

[0154] In more detail, as indicated in Fig. 3 and Fig. 4, according to the illustrated embodiments, the step of setting 102 the parameter p comprises the steps of: - setting 103 the parameter p based on a ratio between the current weight estimate wE and the current total transmission ratio tr.

[0155] In other words, according to these embodiments, the control arrangement 21 is configured to set the parameter p based on the ratio between the current weight estimate wE and the current total transmission ratio tr.

[0156] As can be seen in the upper graph of Fig. 3, according to the illustrated embodiments, the step of operating 105 the engine 1 in the fuel cut allowance mode AM during a motoring phase comprises the step of:

[0157] - allowing 108 stop of fuel supply to the one or more combustion chambers 4 during a non-restricted time period nrt.

[0158] In other words, according to these embodiments, the control arrangement 21 is configured to operate the engine 1 in the fuel cut allowance mode AM during a motoring phase by allowing stop of fuel supply to the one or more combustion chambers 4 during a non-restricted time period nrt.

[0159] The control arrangement 21 may be configured to stop of fuel supply to the one or more combustion chambers 4 by controlling operation of the fuel supply arrangement 6 of the engine during the non-restricted time period nrt until an engine motoring demand is cancelled, for example by the receipt of a positive engine torque demand, a vehicle acceleration demand, or the like.

[0160] Furthermore, as seen in Fig. 3 and Fig. 4, according to the illustrated embodiments, the method 100 comprises the steps of:

[0161] - setting 110 the duration d1 of a fuel cut time period fc1, and during operation in the fuel cut limitation mode LM:

[0162] - stopping 130 fuel supply to the one or more combustion chambers 4 during the fuel cut time period fc1 , and

[0163] - initiating 140 fuel supply to the one or more combustion chambers 4 after the fuel cut time period fc1.

[0164] In other words, according to these embodiments, the control arrangement 21 is configured to set the duration d1 of the fuel cut time period fc1 and to operate the engine 1 in the fuel cut limitation mode LM by stopping fuel supply to the one or more combustion chambers 4 during the fuel cut time period fc1, and initiating fuel supply to the one or more combustion chambers 4 after the fuel cut time period fc1.

[0165] The wording stopping fuel supply to the one or more combustion chambers 4 as used herein may mean that no fuel is supplied to the one or more combustion chambers 4, i.e., that a zero fuel injection rate iF is used. As seen in the lower graph of Fig. 3, the fuel injection rate iF is zero during the fuel cut time period fc1. Moreover, as seen in the lower graph of Fig. 3, the fuel injection rate iF is at a determined level dA during a fuel supply time period fs1 occurring after the initiation of the fuel supply to the one or more combustion chambers 4 at step 140.

[0166] As can be seen in Fig. 4, according to the illustrated embodiments, the step of setting 110 the duration d1 of the fuel cut time period fc1 comprises the step of:

[0167] - setting 111 the duration d1 of the fuel cut time period fc1 based on a current rotational speed rpm of the engine 1.

[0168] In other words, according to the illustrated embodiments, the control arrangement 21 is configured to set the duration d1 of the fuel cut time period fc1 based on a current rotational speed rpm of the engine 1. The current rotational speed rpm of the engine 1 may for example be obtained using data from a crank angle sensor 29 of the vehicle 2.

[0169] Moreover, as can be seen in Fig. 4, according to the illustrated embodiments, the step of setting 111 the duration d1 of the fuel cut time period fc1 comprises the steps of:

[0170] - increasing 112 the duration d1 with increasing rotational speeds rpm, and

[0171] - reducing 113 the duration d1 with reducing rotational speeds rpm.

[0172] In other words, in these embodiments, the control arrangement 21 is configured to set the duration d1 of the fuel cut time period fc1 by increasing the duration d1 with increasing rotational speeds rpm and reducing the duration d1 with reducing rotational speeds rpm.

[0173] Furthermore, as can be seen in Fig. 4, according to the illustrated embodiments, the step of setting 110 the duration d1 of the fuel cut time period fc1 comprises the step of:

[0174] - setting 115 the duration d1 of the fuel cut time period fc1 based on the current total transmission ratio tr. That is, according to the illustrated embodiments, the control arrangement 21 is configured to set the duration d1 of the fuel cut time period fc1 based on the current total transmission ratio tr between the engine 1 and the driven wheels 27 of the vehicle 2.

[0175] Moreover, as can be seen in Fig. 4, according to the illustrated embodiments, the step of setting 115 the duration d1 of the fuel cut time period fc1 comprises the step of:

[0176] - setting 117 the duration d1 of the fuel cut time period fc1 based on the current total transmission ratio tr such that the duration d1 of the fuel cut time period fc1 is increased with reducing total transmission ratios tr and is reduced with increasing total transmission ratios tr.

[0177] In other words, in these embodiments, the control arrangement 21 is configured to set the duration d1 of the fuel cut time period fc1 based on the current total transmission ratio tr such that the duration d1 of the fuel cut time period fc1 is increased with reducing total transmission ratios tr and is reduced with increasing total transmission ratios tr.

[0178] As can be seen in Fig. 3 and Fig. 4, according to the illustrated embodiments, the method 100 comprises the steps of:

[0179] - setting 120 the duration df1 of a fuel supply time period fs1 based on a current rotational speed rpm of the engine 1, and after the step of initiating 140 fuel supply to the one or more combustion chambers 4:

[0180] - supplying 142 fuel to the one or more combustion chambers 4 during the fuel supply time period fs1.

[0181] In other words, in these embodiments, the control arrangement 21 is configured to set the duration df1 of a fuel supply time period fs1 based on a current rotational speed rpm of the engine 1 and to control the fuel supply arrangement 6 to supply fuel to the one or more combustion chambers 4 during the fuel supply time period fs1 after initiating fuel supply to the one or more combustion chambers 4. As can be seen in the lower graph of Fig. 3, the fuel injection rate iF is controlled to a determined level dA during the fuel supply time period fs1 as mentioned above.

[0182] As can be seen in Fig. 3 and Fig. 4, according to the illustrated embodiments, the method 100 comprises the step of:

[0183] - stopping 150 fuel supply to the one or more combustion chambers 4 during a second fuel cut time period fc2 after the fuel supply time period fs1. Accordingly, in these embodiments, the control arrangement 21 is configured to stop fuel supply to the one or more combustion chambers 4 during a second fuel cut time period fc2 after the fuel supply time period fs1. The fuel cut time period fc1 as referred to herein may also be referred to as a first fuel cut time period fc1.

[0184] Moreover, as indicated in Fig. 3 and Fig. 4, according to the illustrated embodiments, the method 100 comprises the step of:

[0185] - setting 122 the duration d2 of the second fuel cut time period fc2 based on at least one of the current rotational speed rpm of the engine 1 and the current total transmission ratio tr.

[0186] In other words, according to these embodiments, the control arrangement 21 is configured to set the duration d2 of the second fuel cut time period fc2 based on at least one of the current rotational speed rpm of the engine 1 and the current total transmission ratio tr.

[0187] Furthermore, as can be seen in Fig. 3 and Fig. 4, according to the illustrated embodiments, the method 100 comprises the step of: initiating 160 fuel supply to the one or more combustion chambers 4 after the second fuel cut time period fc2.

[0188] Thus, according to the illustrated embodiments, the control arrangement 21 is configured to initiate fuel supply to the one or more combustion chambers 4 after the second fuel cut time period fc2.

[0189] As can be seen in Fig. 3 and Fig. 4, according to the illustrated embodiments, the method 100 comprises the steps of:

[0190] - setting 124 the duration df2 of a second fuel supply time period fs2 based on a current rotational speed rpm of the engine 1 , and after the step of initiating 160 fuel supply to the one or more combustion chambers 4:

[0191] - supplying 162 fuel to the one or more combustion chambers 4 during the second fuel supply time period fs2.

[0192] In other words, in these embodiments, the control arrangement 21 is configured to set the duration df2 of the second fuel supply time period fs2 based on a current rotational speed rpm of the engine 1 and to control the fuel supply arrangement 6 to supply fuel to the one or more combustion chambers 4 during the second fuel supply time period fs2 after initiating fuel supply to the one or more combustion chambers 4. As can be seen in the lower graph of Fig. 3, the fuel injection rate iF is controlled to a determined level dA during the second fuel supply time period fs2 as mentioned above. The fuel supply time period fs1 as referred to herein may also be referred to as a first fuel supply time period fs1.

[0193] Accordingly, in summary, according to the illustrated embodiments, the control arrangement 21 is configured to cyclically alternate between stopping supply of fuel to the one or more combustion chambers 4 of the engine 1 during fuel cut time periods fc1, fc2 and supplying fuel to the one or more combustion chambers 4 during fuel supply time period fs1, fs2 upon operation in the fuel cut limitation mode LM. This cyclical alternation may last until an engine motoring demand is cancelled, for example by the receipt of a positive engine torque demand, a vehicle acceleration demand, or the like.

[0194] Likewise, in summary, according to the illustrated embodiments, the control arrangement 21 is configured to, upon operating in the fuel cut allowance mode AM, stopping fuel supply to the one or more combustion chambers 4 during a non-restricted time period nrt until an engine motoring demand is cancelled, for example by the receipt of a positive engine torque demand, a vehicle acceleration demand, or the like.

[0195] A positive engine torque demand, and / or a vehicle acceleration demand, as referred to above, may be received in the control arrangement 21 from an actuator arranged in a driver environment 55 of the vehicle 2, such as an accelerator pedal. As an alternative, or in addition, a positive engine torque demand, and / or a vehicle acceleration demand, may be inputted from an at least partially autonomous driving system of the vehicle 2, from a communication device, or from another type of device or system of the vehicle 2.

[0196] A vehicle acceleration demand, as used herein, means a demand for acceleration of the vehicle 2 in the forward moving direction fd of the vehicle 2. Likewise, a vehicle deceleration demand, also known as vehicle retardation demand, means a demand for deceleration, i.e. , retardation, of the vehicle 2 in the forward moving direction fd of the vehicle 2.

[0197] 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 101 , 10T, 102, 103, 104, 105, 106, 108, 110, 111, 112, 113, 115, 117, 120, 122, 124, 130, 140, 142, 150, 160, and 162. Fig. 5 illustrates a computer-readable medium 200 comprising instructions which, when executed by a computer, cause the computer to carry out the method 100 according to some embodiments of the present disclosure. According to some embodiments, the computer- readable medium 200 comprises a computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out the method 100 according to some embodiments. The computer may be comprised in the control arrangement 21.

[0198] One skilled in the art will appreciate that the method 100 of operating an internal combustion engine 1 of a vehicle 2 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 101, 10T, 102, 103, 104, 105, 106, 108, 110, 111, 112, 113, 115, 117, 120, 122, 124, 130, 140, 142, 150, 160, and 162 described herein. The computer program is usually part of a computer program product which comprises a suitable digital storage medium on which the computer program is stored, such as the computer-readable medium 200 illustrated in Fig. 5. In other words, the computer program product may be a computer readable medium 200 and the computer program may be stored in the computer readable medium 200.

[0199] The control arrangement 21 may comprise a computer which may take the form of substantially any suitable type of hardware or hardware / firmware device implemented using processing circuity such as, but not limited to, a processor, Central Processing Unit (CPU), a controller, an arithmetic logic unit (ALU), a digital signal processor, an Application Specific Integrated Circuit (ASIC), a circuit for digital signal processing (digital signal processor, DSP), a microcomputer, a field programmable gate array (FPGA), a System-on-Chip (SoC), a programmable logic unit, a microprocessor, an application-specific integrated circuit, or any other device capable of electronically performing operations in a defined manner, or other processing logic that may interpret and execute instructions. The herein utilised expression “computer” may represent a processing circuitry comprising a plurality of processing circuits, such as, e.g., any, some or all of the ones mentioned above.

[0200] The control arrangement 21 may further comprise a memory unit, wherein the computer may be connected to the memory unit, which may provide the computer with, for example, stored program code and / or stored data which the computer may need to enable it to do calculations. The computer may also be adapted to store partial or final results of calculations in the memory unit. The memory unit may comprise a physical device utilised to store data or programs, i.e. , sequences of instructions, on a temporary or permanent basis. According to some embodiments, the memory unit may comprise integrated circuits comprising silicon-based transistors. The memory unit may comprise e.g. a memory card, a flash memory, a USB memory, a hard disc, or another similar volatile or non-volatile storage unit for storing data such as e.g. ROM (Read-Only Memory), PROM (Programmable Read- Only Memory), EPROM (Erasable PROM), EEPROM (Electrically Erasable PROM), etc. in different embodiments.

[0201] The control arrangement 21 is connected to components of the internal combustion engine 1 and / or the vehicle 2 for receiving and / or sending input and output signals. These input and output signals may comprise waveforms, pulses, or other attributes which the input signal receiving devices can detect as information and which can be converted to signals processable by the control arrangement 21. These signals may then be supplied to the computer. One or more output signal sending devices may be arranged to convert calculation results from the computer to output signals for conveying to other parts of the vehicle's control system and / or the component or components for which the signals are intended. Each of the connections to the respective components of the vehicle 2 for receiving and sending input and output signals may take the form of one or more from among a cable, a data bus, e.g. a CAN (controller area network) bus, a MOST (media orientated systems transport) bus or some other bus configuration, or a wireless connection.

[0202] In the embodiments illustrated, the vehicle 2 comprises a control arrangement 21 but might alternatively be implemented wholly or partly in two or more control arrangements, two or more control arrangements, or two or more control units.

[0203] Control systems in modern vehicles generally comprise a communication bus system consisting of one or more communication buses for connecting a number of electronic control units (ECUs), or controllers, to various components on board the vehicle. Such a control system may comprise a large number of control units and taking care of a specific function may be shared between two or more of them. Vehicles and engines of the type here concerned are therefore often provided with significantly more control arrangements than depicted in Fig. 1 and Fig. 2, as one skilled in the art will surely appreciate.

[0204] The computer-readable medium 200 may be provided for instance in the form of a data carrier carrying computer program code for performing at least some of the method steps 101, 10T, 102, 103, 104, 105, 106, 108, 110, 111, 112, 113, 115, 117, 120, 122, 124, 130, 140, 142, 150, 160, and 162 according to some embodiments of the method 100 when being loaded into one or more computers of the control arrangement 21. The data carrier may be, e.g. a CD ROM disc, as is illustrated in Fig. 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. Accordingly, in some embodiments, the computer-readable medium 200 may be a non-transitory computer- readable medium, such as a tangible electronic, magnetic, optical, infrared, electromagnetic, and / or semiconductor system, apparatus, and / or device. The computer-readable medium 200 may furthermore be provided as computer program code on a server and may be downloaded to the control arrangement 21 remotely, e.g., over an Internet or an intranet connection, or via other wired or wireless communication systems.

[0205] It is to be understood that the foregoing is illustrative of various example embodiments and that the invention is defined only by the appended independent claims. A person skilled in the art will realize that the example embodiments may be modified, and that different features of the example embodiments may be combined to create embodiments other than those described herein, without departing from the scope of the present invention, as defined by the appended independent claims.

[0206] 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

CLAIMS1. A method (100) of operating an internal combustion engine (1) of a vehicle (2), wherein the engine (1) is configured to provide motive power to the vehicle (2) via driven wheels (27) of the vehicle (2), and wherein the engine (1) comprises one or more combustion chambers (4) and an assembly (41) configured to restrict airflow to the one or more combustion chambers (4) during motoring phases of the engine (1), and wherein the method (100) comprises the step of: determining (104) whether to operate the engine (1) in a fuel cut allowance mode (AM) or a fuel cut limitation mode (LM) during motoring phases of the engine (1) based on at least one of a current weight estimate (wE) of the vehicle (2) and a current total transmission ratio (tr) between the engine (1) and the driven wheels (27) of the vehicle (2).

2. The method (100) according to claim 1 , wherein the method (100) comprises the steps of: setting (102) a parameter (p) based on the current weight estimate (wE) and the current total transmission ratio (tr), operating (105) the engine (1) in the fuel cut allowance mode (AM) during a motoring phase if the parameter (p) is equal to, or below, a threshold value (th), and operating (106) the engine (1) in the fuel cut limitation mode (LM) during a motoring phase of the engine (1) if the parameter (p) is above the threshold value (th).

3. The method (100) according to claim 2, wherein the step of setting (102) the parameter (p) comprises the steps of: setting (103) the parameter (p) based on a ratio between the current weight estimate (wE) and the current total transmission ratio (tr).

4. The method (100) according to any one of the preceding claims, wherein the method comprises the step of, during operation in the fuel cut allowance mode (AM): allowing (108) stop of fuel supply to the one or more combustion chambers (4) during a non-restricted time period (nrt).

5. The method (100) according to any one of the preceding claims, wherein the method comprises the step of, setting (110) the duration (d1) of a fuel cut time period (fc1), and during operation in the fuel cut limitation mode (LM):stopping (130) fuel supply to the one or more combustion chambers (4) during the fuel cut time period (fc1), and initiating (140) fuel supply to the one or more combustion chambers (4) after the fuel cut time period (fc1).

6. The method (100) according to claim 5, wherein the step of setting (110) the duration (d1) of the fuel cut time period (fc1) comprises the step of: setting (111) the duration (d1) of the fuel cut time period (fc1) based on a current rotational speed (rpm) of the engine (1).

7. The method (100) according to claim 6, wherein the step of setting (111) the duration (d1) of the fuel cut time period (fc1) comprises the steps of: increasing (112) the duration (d1) with increasing rotational speeds (rpm), and reducing (113) the duration (d1) with reducing rotational speeds (rpm).

8. The method (100) according to any one of the claims 5 - 7, wherein the step of setting (110) the duration (d1) of the fuel cut time period (fc1) comprises the step of: setting (115) the duration (d1) of the fuel cut time period (fc1) based on the current total transmission ratio (tr).

9. The method (100) according to claim 8, wherein the step of setting (115) the duration (d1) of the fuel cut time period (fc1) comprises the step of: setting (117) the duration (d1) of the fuel cut time period (fc1) based on the current total transmission ratio (tr) such that the duration (d1) of the fuel cut time period (fc1) is increased with reducing total transmission ratios (tr) and is reduced with increasing total transmission ratios (tr).

10. The method (100) according to any one of the claims 5 - 9, wherein the method (100) comprises the steps of: setting (120) the duration (df 1 ) of a fuel supply time period (fs1) based on a current rotational speed (rpm) of the engine (1), and after the step of initiating (140) fuel supply to the one or more combustion chambers (4): supplying (142) fuel to the one or more combustion chambers (4) during the fuel supply time period (fs1).

11. The method (100) according to claim 10, wherein the method (100) comprises the step of: stopping (150) fuel supply to the one or more combustion chambers (4) during a second fuel cut time period (fc2) after the fuel supply time period (fs 1 ).

12. The method (100) according to claim 11 , wherein the method (100) comprises the step of: setting (122) the duration (d2) of the second fuel cut time period (fc2) based on at least one of the current rotational speed (rpm) of the engine (1) and the current total transmission ratio (tr).

13. The method (100) according to any one of the preceding claims, wherein the vehicle (2) comprises a transmission (3) controllable between at least two different gears to provide at least two different transmission ratios between the engine (1) and the driven wheels (27) of the vehicle (2), and wherein the method (100) comprises the step of: obtaining (101) the current total transmission ratio (tr) between the engine (1) and the driven wheels (27) of the vehicle (2) based on a current gear engaged in the transmission (3).

14. 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 1 - 13.

15. 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 1 - 13.

16. A control arrangement (21) configured to control operation of an internal combustion engine (1) of a vehicle (2), wherein the engine (1) is configured to provide motive power to the vehicle (2) via driven wheels (27) of the vehicle (2), and wherein the engine (1) comprises one or more combustion chambers (4) and an assembly (41) configured to restrict airflow to the one or more combustion chambers (4) during motoring phases of the engine (1), and wherein the control arrangement (21) is configured to: determine whether to operate the engine (1) in a fuel cut allowance mode (AM) or a fuel cut limitation mode (LM) during motoring phases of the engine (1) based on at least one of a current weight estimate (wE) of the vehicle (2) and a current totaltransmission ratio (tr) between the engine (1) and the driven wheels (27) of the vehicle (2).

17. A vehicle (2) comprising an internal combustion engine (1) configured to provide motive power to the vehicle (2) via driven wheels (27) of the vehicle (2), wherein the engine (1) comprises one or more combustion chambers (4) and an assembly (41) configured to restrict airflow to the one or more combustion chambers (4) during motoring phases of the engine (1), and wherein the vehicle (2) comprises a control arrangement (21) according to claim 16.

18. The vehicle (2) according to claim 17, wherein the engine (1) is a spark ignition engine.

19. The vehicle (2) according to claim 17 or 18, wherein the vehicle (2) is a heavy road vehicle, such as a truck or a bus.

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