Method for adjusting a camshaft of an internal combustion engine and internal combustion engine with an adjustable camshaft

Abstract

A method for adjusting a camshaft of an internal combustion engine during a stop phase and during a subsequent restart phase of the internal combustion engine, wherein intake valves and / or exhaust valves of the internal combustion engine are controlled by the camshaft adjustable with a camshaft adjuster; and wherein a target starting position of the camshaft adjuster defines control times of the intake valves and / or exhaust valves at which a mechanical work required to start the internal combustion engine is reduced and / or a pollutant emission of the internal combustion engine is reduced, comprising the following steps: - Setting the camshaft adjuster to a stop target position during the stop phase; - setting the camshaft adjuster from the stop target position to the start target position during a first section of the start phase; and - Setting the camshaft adjuster as a function of measured operating parameters of the internal combustion engine during a second section of the starting phase, whereby - the stop target position defines a delayed time for closing the exhaust valves and an early time for opening the intake valves.

Description

Field of the invention

[0001] The invention relates to a method for adjusting a camshaft of an internal combustion engine during a stop phase and during a subsequent restart phase of the internal combustion engine. Such methods are used in particular in so-called start-stop concepts for internal combustion engines. Furthermore, the invention relates to an internal combustion engine with a camshaft adjustable by a camshaft adjuster.

[0002] Various solutions for start-stop concepts for internal combustion engines are known from the state of the art, which serve primarily to save fuel. These concepts envisage stopping the fuel supply in the event of a brief stop, for example, a vehicle stopped at a red light or in a traffic jam, thereby interrupting the operation of the internal combustion engine. Such concepts can reduce fuel consumption by, for example, 3% to 5% based on the New European Driving Cycle (NEDC). At the same time, however, the implementation of a start-stop concept significantly increases the specified start frequency. Under normal driving conditions, the expected start frequency of a motor vehicle's internal combustion engine increases from 50,000 to 3,000,000. In addition, start-stop concepts initially lead to increased noise emissions, for example, an increase in the NVH (Noise Vibration Harshness) level in a motor vehicle.If the start-stop concept is implemented using an electric starter motor, the starter motor must be designed for the increased starting frequency. The starter motor must be larger, which increases the cost and mass of the starter motor. Furthermore, the vehicle's power supply system is loaded with each start, requiring larger dimensions for the alternator and battery. Furthermore, electrical energy must be consumed for each start, which reduces the energy-saving potential of the start-stop concept. The fundamentals of such processes can be found on pages 52 and 53 of Ottomotor-Management, Robert Bosch GmbH (ed.), 2nd ed., Springer Fachmedien Wiesbaden, 2003, ISBN 978-3-322-93930-2.

[0003] State-of-the-art solutions also include partial or complete replacement of the electric starter motor. In this case, the combustion engine is started by igniting a fuel located in at least one of the cylinders of the stationary combustion engine. This type of start is also known as a direct start. To achieve a direct start, the piston of the respective cylinder must be within a narrow crankshaft window located approximately 100° past top dead center of the crankshaft.

[0004] DE 103 51 891 A1 discloses a method and a control unit for restarting an internal combustion engine. The restart occurs during a current operating period after the internal combustion engine was shut down at the end of a previous operating period. To enable the internal combustion engine to be restarted without a starter motor, fuel is first injected into the intake manifold of the internal combustion engine when its cylinder is in an intake stroke during the last full revolution of the previous operating period, so that the combustion chamber of the cylinder is then filled with a fuel-air mixture. Furthermore, at the end of the previous operating state, the piston of the cylinder is moved into a standstill position, in which the piston assumes a power stroke position and the fuel-air mixture remains enclosed in the combustion chamber.Finally, the internal combustion engine is restarted by igniting the fuel-air mixture trapped in the combustion chamber while the mixture is still ignitable. A disadvantage of this method is that moving the cylinder's piston to a stationary position requires precise positioning of the piston, which requires work to compress the fuel-air mixture.

[0005] EP 1 586 765 A1 discloses a method and a control system for positioning a crankshaft when shutting down an internal combustion engine. An electric motor coupled to a crankshaft of the internal combustion engine is controlled to position the crankshaft at a starting angle. The control system comprises a detection device for receiving and / or determining a position angle and / or the rotational speed of the crankshaft, as well as a control unit capable of controlling an electric motor in a closed-loop control mode depending on the rotational speed of the crankshaft and moving the crankshaft to the starting angle after the internal combustion engine is stopped.The internal combustion engine is started from this starting angle, with the control unit designed to control the electric motor in a controlled mode below a predetermined limit speed, independent of the speed, so that the crankshaft is adjusted to the starting angle. This solution has the disadvantage that positioning the crankshaft when shutting down the internal combustion engine is complex and also requires additional energy.

[0006] DE 197 43 492 A1 discloses a method for starting an internal combustion engine, in particular that of a motor vehicle. This method is intended for an internal combustion engine equipped with a piston movable within a cylinder, which can undergo an intake phase, a compression phase, a working phase, and an exhaust phase. The fuel is injected directly into a combustion chamber defined by the cylinder and piston, either in a first operating mode during the compression phase or in a second operating mode during the intake phase. According to this previously known method, the fuel is injected in a first injection directly into the combustion chamber whose associated piston is in the working phase. However, the power that can be generated using this method to start the internal combustion engine is often insufficient.

[0007] DE 10 2006 012 384 A1 discloses a starting method for an internal combustion engine with direct injection, which, in a hybrid vehicle, has a spark-ignition combustion engine and an electric motor for its drive. The combustion engine is started from a standstill without mechanical excitation by using the electric motor to drive the hybrid vehicle to bring at least one cylinder into a suitable starting position between 30° and 150°, preferably between 70° and 90°, crank angle after its top dead center after the compression phase. A quantity of fuel is injected into this one or more cylinders and ignited after injection. This method for implementing the start-stop concept is limited to hybrid vehicles.

[0008] DE 10 2004 046 182 A1 discloses a method for combustion-assisted start-stop operation of an engine with cylinder valve deactivation. This method initially comprises a step of adjusting a throttle valve to provide an air mass flow to a vehicle engine sufficient to create starting torque. Furthermore, fuel sufficient to create starting torque is injected into the engine cylinder during an intake stroke of a cylinder. Furthermore, the operation of a spark plug is interrupted, and an exhaust valve and an intake valve of the cylinder are blocked. In this state, the engine is shut down. To switch on the engine, a piston of the cylinder is positioned between a top dead center of a compression stroke and a bottom dead center of a power stroke, or between a top dead center of an exhaust stroke and a bottom dead center of an intake stroke.A fuel-air charge sufficient to create starting torque is ignited in the cylinder by the spark plug. Finally, the intake and exhaust valves are activated. This process also requires complex piston positioning during the engine shutdown process, which requires mechanical work to compress the fuel-air mixture. Furthermore, this process cannot guarantee that the fuel-air mixture will be largely ideally combusted during the start-up process, resulting in increased pollutant emissions.

[0009] JP 2005 - 146 908 A also discloses a method for adjusting a camshaft of an internal combustion engine during a stop phase and during a subsequent restart phase of the internal combustion engine. DE 103 60 033 A1, JP H11 - 93 714 A, and DE 603 ​​01 539 T2 disclose further methods for adjusting a camshaft.

[0010] The object of the present invention, based on DE 10 2004 046 182 A1, is to facilitate the restart of the internal combustion engine, for example within the framework of a start-stop concept of an internal combustion engine, and / or to reduce pollutant emissions during the restart.

[0011] The stated object is achieved by a method according to the appended claim 1 and by an internal combustion engine according to the independent claim 19.

[0012] The method according to the invention serves to adjust a camshaft of an internal combustion engine during a stop phase and during a restart phase of the internal combustion engine. The camshaft controls intake valves and / or exhaust valves of the internal combustion engine. This can be a simpler camshaft that controls all intake valves and exhaust valves; or it can be a multiple camshaft, with each individual camshaft controlling only a portion of the intake valves or exhaust valves. Basically, the camshaft controls the opening and closing of the intake valves and / or exhaust valves. The camshaft is adjustable by a camshaft adjuster, so that the times for opening and closing the intake and exhaust valves can be varied in relation to the position of a crankshaft of the internal combustion engine.The camshaft adjuster allows the internal combustion engine to be adapted to different operating conditions and / or requirements of the internal combustion engine. The target starting position of the camshaft adjuster defines the control timing of the intake valves and / or the exhaust valves at which the mechanical work required to start the internal combustion engine is reduced and / or pollutant emissions from the internal combustion engine are reduced. The mechanical work required to start the internal combustion engine is reduced in particular when the work required to compress the fuel-air mixture in the cylinder is reduced, which is the case, for example, when there is a smaller amount of fuel-air mixture in the cylinder than during normal operation of the internal combustion engine. This can be achieved, for example, by the intake valves closing later than is the case during normal operation.At the same time, pollutant emissions can be reduced. The method according to the invention provides that the camshaft adjuster is set to a desired stop position during the stop phase. This ensures that the camshaft adjuster is in a defined position so that this position is also known during the subsequent start phase of the internal combustion engine, even if the position of the camshaft adjuster cannot yet be determined using sensors during the start phase. During a first section of the start phase, the camshaft adjuster is moved from the desired stop position to the desired start position. This step enables a starting process of the internal combustion engine that is optimized with regard to the mechanical work required for starting and / or the pollutant emissions occurring.During a second part of the start-up phase, the camshaft adjuster is adjusted based on measured operating parameters of the internal combustion engine. This ensures that the continued start-up of the internal combustion engine is also optimal, taking into account the current operating state of the internal combustion engine. Measured operating parameters of the internal combustion engine can be used for this purpose, although these are not necessarily available during the first part of the start-up phase.

[0013] A particular advantage of the method according to the invention is that it can be universally used for internal combustion engines. The method can be applied, for example, to four-stroke engines based on the Otto principle. The method is suitable for start-stop concepts, regardless of whether a starter motor is used or not. The method is applicable regardless of the type of camshaft adjuster drive, for example, for electric motor- or hydraulically driven camshaft adjusters. Furthermore, the method is also suitable for internal combustion engines that do not implement a start-stop concept. Even in such internal combustion engines, the method according to the invention leads to a reduction in fuel consumption.

[0014] If the method according to the invention is used for an internal combustion engine with a starter motor, the starter motor can be dimensioned smaller. This requires less installation space for the starter motor and reduces overall costs. In the case of belt-driven starter motors, the load on the belt is reduced. The efficiency of the overall system is increased because less work is required for the starting process. This simultaneously reduces the load on the vehicle's power supply network, for example.

[0015] If the method according to the invention is used within the framework of a start-stop concept, there is the further advantage that the direct start can also be carried out at higher and lower operating temperatures of the combustion engine compared to implementations according to the prior art.

[0016] The present invention is based on the discovery that cylinder filling and residual gas content can be influenced by selecting the timing of the intake and exhaust valves. Furthermore, the effective compression ratio can be influenced by selecting the timing. Finally, the work required to compress the fuel-air mixture can be influenced by selecting the timing, particularly the timing of the intake valve closing. Until the intake valves close, a piston moving from bottom dead center to top dead center can push the air or fuel-air mixture back into the intake manifold of the internal combustion engine with little or no load. This reduces the work required to compress the fuel-air mixture ultimately found in the cylinder. At the same time, the mechanical work required to start the internal combustion engine is reduced.

[0017] In a particular embodiment of the method according to the invention, the target start position and the target stop position are identical. Thus, the camshaft adjuster is already brought into the target start position during the engine's stop phase, which enables an optimal start. Alternatively, the method can be implemented such that the target start position is close to the target stop position, in order to quickly adjust the target start position during the first part of the start phase.

[0018] In a particular embodiment of the method according to the invention, the target stop position is defined by a stop on the camshaft adjuster. This can, for example, be one of the stops that determine the earliest timing or the latest timing of the intake and exhaust valves. Setting the camshaft adjuster to a stop serves to ensure a defined target stop position, enabling a reliable setting of the camshaft adjuster to the target start position during the first section of the starting phase.

[0019] The target stop position defines a delayed point in time for the exhaust valves to close and an advanced point in time for the intake valves to open. This leads to a significant overlap between the engine's operating phases and a high proportion of residual gas during combustion in the engine cylinder. Ultimately, this influences the engine's starting process, as the amount of fuel-air mixture in the cylinder is fixed at the beginning of the starting process.

[0020] The target start position defines a delayed timing for the intake valves to close. This reduces the amount of fuel-air mixture to be charged into the cylinder, thus further reducing the effective compression ratio. An advanced or delayed timing is defined as a timing that is earlier or later in the timing sequence than the timing set during normal operation of the internal combustion engine.

[0021] In a preferred embodiment of the method according to the invention, the setting of the camshaft adjuster into the target stop position during the stop phase begins precisely when a stop signal provided via a data bus is present and / or the speed of the internal combustion engine falls below a defined value. For example, an engine control unit can transmit a stop flag via a Controller Area Network (CAN), which signals an intention to stop the internal combustion engine. A further signal, which signals a stop of the internal combustion engine, can be triggered when the speed of the internal combustion engine falls below a defined value. The presence of one or both of the two signals results in the camshaft adjuster being set to the target stop position. The target stop position must be maintained until the end of the stop phase, i.e. until the crankshaft comes to a standstill.If it cannot be guaranteed that the camshaft adjuster will be fully adjusted to the target stop position during the stop phase, a special embodiment of the method according to the invention can store a measured value for the ultimately reached position of the camshaft adjuster in a memory. During the start-up phase of the internal combustion engine, the stored value serves as a starting point for adjusting the camshaft adjuster to the target start position.

[0022] In a preferred embodiment of the method according to the invention, the camshaft adjuster is adjusted continuously during the second part of the starting phase. Thus, the internal combustion engine can be continuously adapted to its current operating parameters even during the second part of the starting phase. The internal combustion engine can thus be quickly transferred to the desired operating mode, further improving the starting behavior of the internal combustion engine.

[0023] The adjustment of the camshaft adjuster during the second section of the starting phase preferably takes place as a function of the speed of the crankshaft, the speed of the camshaft, and / or the speed of an electric motor driving the camshaft adjuster. This embodiment of the method according to the invention is particularly suitable for internal combustion engines that use a camshaft adjuster driven by an electric motor. Three speeds can be measured, which provide information about the current position of the camshaft adjuster. The speed of the camshaft and the speed of the crankshaft can be related at a specific time, from which the phase angle between the camshaft and the crankshaft can be derived.If the camshaft speed cannot be measured during the start-up or stop-off phase, the speed of the electric motor can be measured, from which the phase between the camshaft and the crankshaft can be determined via a three-shaft gear relationship. This phase can be checked as soon as a new measured value for the camshaft speed is available. During the start-up phase, measured values ​​for the speed of the crankshaft, the camshaft, and the electric motor driving the camshaft adjuster are often only available above a certain minimum speed. In these cases, the phase between the camshaft and the crankshaft cannot always be determined below this minimum speed.In order to move the camshaft adjuster into the target starting position or to hold it there, the electric motor can be moved towards the target starting position, which is defined, for example, by a stop. This can be done, for example, by specifying the voltage or current for operating the electric motor or by means of pulse width modulation. As soon as measured values ​​for the speeds of the crankshaft and the electric motor are available, the target starting position can be maintained precisely. In the second section of the starting phase, the position of the camshaft adjuster can be continuously adjusted to the speeds or other operating parameters. If the target starting position cannot be set precisely enough, the camshaft adjuster can be moved again to a stop in order to obtain an exact starting position.During this time, no fuel is injected, so the work required to compress the cylinder volume remains low.

[0024] To accurately measure the fuel flow during the start-up phase, it is necessary to know which cylinder is in a gas exchange phase and the relative position of the piston and intake valve. If this is not known, fuel must be injected into a randomly selected cylinder. This leads, in particular, to high hydrocarbon emissions during the start-up phase. Once the camshaft and crankshaft speeds can be measured during the start-up phase and synchronized, the intake and exhaust valves can be controlled according to their piston positions.

[0025] Preferably, the camshaft adjuster is adjusted during the second part of the start-up phase, similar to the way it is adjusted during continuous engine operation. This results in a short start-up phase and a low NVH level during the start-up phase.

[0026] In a preferred embodiment of the method according to the invention, the target starting position is defined as a function of current operating parameters of the internal combustion engine. These operating parameters can be, for example, measured values ​​for the temperatures of a cooling water, an engine oil, and / or intake air, as well as for atmospheric pressure and / or air humidity and / or for a combustion air ratio λ of the internal combustion engine. This allows the restart to be adapted to the current state of the internal combustion engine, thereby further reducing the mechanical work required to start the internal combustion engine and / or the pollutant emissions of the internal combustion engine during the starting phase.

[0027] Preferably, the target starting position represents an optimum between reducing the mechanical work required to start the internal combustion engine and reducing pollutant emissions from the internal combustion engine during the starting phase. In many applications, for example in automotive engineering, it is desirable to minimize both variables in order to save fuel on the one hand and reduce pollutant emissions on the other. The method according to the invention allows both goals to be achieved, but for this, an optimum must be selected, which is defined by the target starting position.

[0028] The camshaft adjuster is preferably adjusted during the second part of the starting phase in such a way that the second part of the starting phase is shortened and / or that noise generated by the internal combustion engine during the starting phase is reduced. This allows the method to meet the requirements, particularly in the implementation of start-stop concepts.

[0029] The method according to the invention is also suitable for internal combustion engines formed by a V-engine. V-engines are reciprocating piston engines in which cylinders are arranged in two rows, as so-called cylinder banks. The one or more camshafts control the intake valves and / or the exhaust valves of cylinders in both cylinder banks. One or more of the camshafts can each be adjusted by one of the camshaft adjusters. The one or more camshaft adjusters are to be adjusted according to the method according to the invention. The method is preferably used for V-engines in which the intake valves are controlled by a first of the camshafts and the exhaust valves are controlled by a second of the camshafts. The first camshaft is adjustable by a first of the camshaft adjusters. The second camshaft is adjustable by a second of the camshaft adjusters.The adjustment of the first camshaft by the first camshaft adjuster and the adjustment of the second camshaft by the second camshaft adjuster preferably occur synchronously, with a deviation between the first camshaft and the second camshaft having a window width of 0 to 3 degrees cam angle, i.e., relative to the angular position of the first and second camshafts. This window width is particularly preferably from 0 to 1.5 degrees and very particularly preferably from 0 to 0.5 degrees.

[0030] The internal combustion engine according to the invention firstly has a camshaft for controlling the intake valves and exhaust valves of the internal combustion engine. This can be a simpler camshaft that controls all intake valves and exhaust valves; or it can be a multiple camshaft, with each individual camshaft controlling only a portion of the intake valves or exhaust valves. Essentially, the camshaft controls the opening and closing of the intake valves and exhaust valves. The camshaft is adjustable by a camshaft adjuster, so that the times for opening and closing the intake valves and exhaust valves can be varied in relation to the position of a crankshaft of the internal combustion engine. The camshaft adjuster is controlled by a camshaft control system.During a stop phase of the internal combustion engine, the camshaft control enables the camshaft adjuster to be set to a stop target position in order to bring the camshaft into a defined position so that this position is then also known during a subsequent start phase of the internal combustion engine, even if the position of the camshaft adjuster cannot yet be determined using sensors during the start phase. During an initial section of the start phase, the camshaft control enables the camshaft adjuster to be set from the stop target position to a start target position. The start target position of the camshaft adjuster defines the control timing of the intake valves and exhaust valves at which the mechanical work required to start the internal combustion engine is reduced and / or the pollutant emissions of the internal combustion engine are reduced.This step enables a starting process of the internal combustion engine that is optimized with regard to the mechanical work required for starting and / or the resulting pollutant emissions. During a second section of the starting phase, the camshaft control allows the camshaft adjuster to be adjusted depending on measured operating parameters of the internal combustion engine. This ensures that the continued starting of the internal combustion engine is also optimal with regard to the current operating state of the internal combustion engine. Measured operating parameters of the internal combustion engine can be used for this purpose, which are not necessarily available during the first section of the starting phase.

[0031] The inventive internal combustion engine demonstrates all the advantages and areas of application of the inventive method for adjusting a camshaft of an internal combustion engine during a stop phase and during a restart phase of the internal combustion engine. All described embodiments of the inventive method for adjusting a camshaft can also be implemented in embodiments of the inventive internal combustion engine.

Claims

[1] A method for adjusting a camshaft of an internal combustion engine during a stop phase and during a subsequent restart phase of the internal combustion engine, wherein intake valves and / or exhaust valves of the internal combustion engine are controlled by the camshaft adjustable by a camshaft adjuster; and wherein a target starting position of the camshaft adjuster defines control times of the intake valves and / or the exhaust valves at which a mechanical work required to start the internal combustion engine is reduced and / or a pollutant emission of the internal combustion engine is reduced, comprising the following steps: - Setting the camshaft adjuster to a stop target position during the stop phase; - setting the camshaft adjuster from the stop target position to the start target position during a first section of the start phase; and - Setting the camshaft adjuster as a function of measured operating parameters of the internal combustion engine during a second section of the starting phase, whereby - the stop target position defines a delayed time for closing the exhaust valves and an early time for opening the intake valves. [2] Method according to claim 1, characterized by that the start target position and the stop target position are identical. [3] Method according to claim 1 or 2, characterized by that the target stop position is defined by a stop of the camshaft adjuster. [4] Method according to one of claims 1 to 3, characterized by that the target start position defines a delayed time for closing the intake valves. [5] Method according to one of claims 1 to 4, characterized bythat the setting of the camshaft adjuster into the stop target position during the stop phase begins when an electronic signal for stopping is provided via a data bus and / or the speed of the internal combustion engine falls below a defined value. [6] Method according to one of claims 1 to 5, characterized by that a measured value for the position of the camshaft adjuster is stored in a memory at the end of the stop phase if it cannot be guaranteed that the camshaft adjuster will be fully set to the stop target position. [7] Method according to one of claims 1 to 6, characterized by that the camshaft adjuster is adjusted continuously during the second part of the starting phase. [8] Method according to one of claims 1 to 7, characterized bythat the adjustment of the camshaft adjuster during the second section of the starting phase takes place as a function of the speed of a crankshaft, the speed of the camshaft and / or the speed of an electric motor for driving the camshaft adjuster. [9] Method according to claim 7 or 8, characterized by that the adjustment of the camshaft adjuster during the second part of the starting phase takes place in the same way as during continuous operation of the internal combustion engine. [10] Method according to one of claims 1 to 9, characterized by that the target starting position is defined as a function of the current operating parameters of the internal combustion engine. [11] Method according to claim 10, characterized bythat the target starting position is defined as a function of measured values ​​for temperatures of a cooling water, an engine oil and / or an intake air as well as for an air pressure and / or a combustion air ratio of the internal combustion engine. [12] Method according to one of claims 1 to 11, characterized by that the target starting position represents an optimum between reducing the mechanical work required to start the internal combustion engine and reducing the pollutant emissions of the internal combustion engine. [13] Method according to one of claims 1 to 12, characterized by that the adjustment of the camshaft adjuster during the second section of the starting phase is carried out in such a way that the second section of the starting phase is shortened and / or that noises of the internal combustion engine occurring during the starting phase are reduced. [14] Method according to one of claims 1 to 13, characterized bywhich serves to adjust the camshaft of a V-engine with two cylinder banks, wherein the inlet valves and / or the exhaust valves of cylinders of both cylinder banks of the V-engine are controlled by one or more of the camshafts, wherein one or more of the camshafts are each adjustable by one of the camshaft adjusters. [15] Method according to claim 14, characterized by that the intake valves are controlled by a first of the camshafts, and that the exhaust valves are controlled by a second of the camshafts; wherein the first camshaft is adjustable by a first of the camshaft adjusters, and wherein the second camshaft is adjustable by a second of the camshaft adjusters. [16] Method according to claim 15, characterized bythat the setting of the first camshaft by the first camshaft adjuster and the setting of the second camshaft by the second camshaft adjuster take place synchronously, wherein a deviation between the first camshaft and the second camshaft has a window width of 0 to 3 degrees based on the angular position of the first camshaft and the second camshaft. [17] Method according to claim 16, characterized by that the deviation between the first camshaft and the second camshaft has a window width of 0 to 1.5 degrees relative to the angular position of the first camshaft and the second camshaft. [18] Method according to claim 17, characterized by that the deviation between the first camshaft and the second camshaft has a window width of 0 to 0.5 degrees relative to the angular position of the first camshaft and the second camshaft. [19] Internal combustion engine with a camshaft adjustable by a camshaft adjuster for controlling intake valves and exhaust valves of the internal combustion engine, and with a camshaft control for controlling the camshaft adjuster, characterized by that the camshaft control: - enables the camshaft adjuster to be set to a desired stop position during a stop phase of the internal combustion engine; - in a first section of a subsequent restart phase of the internal combustion engine, it is possible to adjust the camshaft adjuster from the stop target position to a start target position, wherein the start target position defines control times of the intake valves and the exhaust valves at which a mechanical work required to start the internal combustion engine is reduced and / or a pollutant emission of the internal combustion engine is reduced; and - in a second section of the restart phase, the camshaft adjuster can be adjusted depending on measured operating parameters of the internal combustion engine, whereby - the stop target position defines a delayed time for closing the exhaust valves and an early time for opening the intake valves. [20] Internal combustion engine according to claim 19, characterized by that it is a V-engine.