Drive system with internal combustion engine and intake valves with high touchdown speeds

Abstract

Drive system for a motor vehicle (1) with an internal combustion engine (3) having at least one cylinder opening (10) within which a reciprocating piston (16) is cyclically movable between a top dead center (TDC) and a bottom dead center (BDC), wherein the cyclic movement of the reciprocating piston (16) is coupled to a rotary movement of a crankshaft (20), wherein an inlet of fresh gas into the cylinder opening (10) can be controlled by means of exactly one inlet valve (18) or two inlet valves (18) per cylinder opening (10), which is / are actuated by means of a valve train, wherein the inlet valve (18) or the inlet valves (18) are opened and closed again in accordance with the course of a valve lift curve (31) when actuated,wherein the valve lift curve (31) depicts the course of the opening lift (h) of the inlet valve (18) or inlet valves (18) as a function of the rotation angle (α) of the crankshaft (20) and wherein the inlet valve (18) or inlet valves (18) is / are closed between BDC-150°KW and BDC-30°KW or between BDC+30°KW and BDC+150°KW, wherein at an operating speed of the internal combustion engine (3) of 4500 rpm the maximum closing speed when the inlet valve (18) or inlet valves (18) make contact is at least 0.36 m / s.

Description

[0001] The invention relates to a drive system for a motor vehicle with an internal combustion engine that can be operated according to a Miller or an Atkinson combustion process. The invention also relates to a motor vehicle with such a drive system.

[0002] Miller or Atkinson combustion processes are used in internal combustion engines, particularly (spark-ignition and quantity-controlled) gasoline engines, to increase efficiency. A Miller combustion process is characterized by the fact that the intake valves of the corresponding internal combustion engines are actuated with an early intake valve closing, which occurs significantly before the respective bottom dead center of the cyclically moving pistons, while an Atkinson combustion process uses a late intake valve closing, which occurs significantly after the respective bottom dead center of the pistons. These intake timings, which reduce the volumetric efficiency during operation of the internal combustion engines, allow the pressure in the fresh air / fuel mixture to be increased, while maintaining the same fresh air / fuel mixture mass supplied to the individual combustion chambers of the internal combustion engine per operating cycle.This results, firstly, in a reduction of throttling in the combustion engines in the partial load range, and secondly, in a decrease in the effective compression ratio, which lowers the combustion chamber charge temperature and thus reduces the tendency to knock at higher loads during the operation of the combustion engines.

[0003] Valve trains with instantaneously closing intake valves represent the theoretical ideal from a fluid dynamics perspective, as they would either completely prevent the flow of fresh air when closed or, when (fully) open, ensure the least restricted flow of fresh air due to maximum valve opening. In real valve trains, however, the intake valves move from the fully closed position, where they rest on their respective valve seats, at a limited speed until they reach their maximum opening stroke. Until this maximum stroke is reached, the intake valves are therefore only partially open, thus revealing only relatively small valve openings that significantly restrict the flow of fresh air.The greater the achievable acceleration and the achievable opening and closing speeds of the gas exchange valves of internal combustion engines, the closer the throttling losses caused by the gas exchange valves approach the theoretical ideal.

[0004] In the valve trains typically used for internal combustion engines in motor vehicles, where the gas exchange valves are directly actuated by camshafts, maximizing achievable accelerations and opening and closing speeds of the gas exchange valves is limited by the permissible surface pressures between valve train components, the spring forces of the valve springs (which are dimensioned as low as possible to minimize friction between the valve train components), and the maximum intended operating speed of the valve train. Regarding the maximum closing speeds, and specifically the speeds of the gas exchange valves when they come into contact with the valve seats, a maximum permissible acoustic excitation of the internal combustion engine caused by the gas exchange valves coming into contact with the valves also plays a role.Maximum permissible wear on the valve seats, minimum achievable valve train masses and the maximum operating speed of the valve train also influence the maximum achievable accelerations as well as the opening and closing speeds of the gas exchange valves.

[0005] Both the maximum valve accelerations (in time) and the valve impact velocities (in time) increase with the operating speeds of the internal combustion engines. Therefore, the maximum permissible valve accelerations (in angle) and the valve impact velocities (in angle) of valve trains are limited by the maximum operating speeds of the internal combustion engines.

[0006] To minimize charge exchange losses, the typical approach is to increase the fullness of the valve lift curve by maximizing the resulting valve accelerations. Simultaneously, the maximum valve impact velocity is limited to an acoustically acceptable level.

[0007] In internal combustion engines whose intake valves close near or shortly after the bottom dead center of the corresponding pistons, the valve closing ramp occurs within a time window in which only very small fresh gas mass flows pass through the intake valves. In such engines, the design of the intake valve closing ramp has essentially no thermodynamic influence.

[0008] WO 00 / 68565 A1 discloses an internal combustion engine that can be operated using a Miller combustion process, wherein the gas exchange valves of the internal combustion engine are optimized to achieve the lowest possible throttling losses in the gas flows passing through them. For this purpose, the gas exchange valves are geometrically designed such that they release their respective valve openings only after a relatively long initial phase of the opening strokes. As a result, the gas exchange valves already exhibit relatively high speeds when the valve openings are released, thus making the time intervals until the maximum opening strokes, and therefore the maximum valve openings, are relatively short.

[0009] DE 10 2014 006 032 A1 discloses an internal combustion engine that can be operated using a Miller combustion process and that has at least three intake valves per combustion chamber. This relatively large number of intake valves allows them to be relatively small and consequently have correspondingly small masses, which should enable relatively high opening and closing speeds.

[0010] DE 196 27 982 A1 discloses a hydraulic lash compensating element for a camshaft-based valve train of an internal combustion engine. The closing speed transmitted to a gas exchange valve is said to be capable of reaching up to 40 µm / °NW.

[0011] The invention was based on the objective of optimizing an internal combustion engine for a motor vehicle, particularly with regard to the achievable efficiency.

[0012] This problem is solved in a drive system with an internal combustion engine according to claim 1. A motor vehicle with such a drive system is the subject of claim 7. Advantageous embodiments of the drive system and the motor vehicle according to the invention are the subject of further claims and / or will become apparent from the following description of the invention.

[0013] According to the invention, a drive system for a motor vehicle is provided, comprising an internal combustion engine having at least one cylinder opening and preferably several cylinder openings, within which a reciprocating piston is cyclically movable between top dead center (TDC) and bottom dead center (BDC), wherein the cyclic movement of the reciprocating piston is coupled to a rotary movement of a crankshaft. Preferably, the internal combustion engine can be a four-stroke engine, so that it is operated in a fired load operation with four strokes or piston strokes per operating cycle (working cycle), wherein only one of these strokes is a power stroke in which work is produced by the piston.The intake of fresh gas into the cylinder opening or combustion chamber, which is partially bounded by a cylinder wall and the piston, is controlled by exactly one intake valve or by two intake valves per cylinder opening. The intake valve(s) is / are actuated by a valve train, whereby, upon actuation, the intake valve(s) opens and closes according to the curve of a valve lift. The valve lift curve represents the opening stroke of the intake valve as a function of the crankshaft rotation. The valve train preferably comprises one or more camshafts that directly or indirectly cause the movement of the intake valve(s). Alternatively or additionally, the valve train may include any other actuators, such as electromechanical or hydraulic actuators.

[0014] According to the invention, the intake valve(s) are closed to implement a Miller combustion process or an Atkinson combustion process either in the range between UT-150°KW and UT-30°KW (°KW: crankshaft rotation angle) or in the range between UT+30°KW and UT+150°KW, wherein, in a four-stroke configuration of the internal combustion engine, bottom dead center (BDC) is the point between an intake stroke and the subsequent compression stroke of the piston. An intake valve is considered closed, in a known manner, with a remaining stroke of 1 mm.It has become established practice to consider an intake valve, or more generally a gas exchange valve, of an internal combustion engine as closed when the remaining stroke is 1 mm, because in conventional internal combustion engines, at least in those not operated using a Miller or Atkinson combustion process, no relevant gas mass flow usually passes through the intake or gas exchange valve after such a remaining stroke.

[0015] According to the invention, the valve train is further designed such that the maximum closing speed when the intake valve(s) come into contact with the valve seat, and preferably also the maximum opening speed when the intake valve(s) come out of the valve seat, is at least 0.36 m / s, preferably at least 0.5 m / s, and particularly preferably at least 0.75 m / s, at an operating speed of the internal combustion engine of 4500 rpm. The coming into contact with the intake valve(s) is defined as the portion of the closing movement from a residual stroke of 0.2 mm. Similarly, the lifting of the intake valve(s) is defined as the portion of the opening movement up to an opening stroke of 0.2 mm.

[0016] According to the invention, it is therefore provided that, in an internal combustion engine operated by means of a Miller or Atkinson combustion process, at least a relatively high maximum closing speed is achieved when the intake valve(s) engage. This allows throttling losses in the fresh gas flow to be minimized to a relevant extent.This is due to the combination with the operation of the internal combustion engine according to a Miller or Atkinson combustion process, because this results in relatively large pressure differentials over the intake valve(s) even when they are touching down and, to a lesser extent, also when they are lifting off (compared to a conventionally operated internal combustion engine where the intake valves close in the region of bottom dead center), which is due to the relatively large time interval between the closing of the intake valve(s) and the bottom dead center of the corresponding piston movement.

[0017] The relatively high closing speed provided for in the invention when the intake valve(s) engage can lead to a relatively strong acoustic excitation. The inventors recognized that this disadvantage can be more than compensated for by the advantage of reduced throttling of the fresh gas flow. This also applies to internal combustion engines according to the invention, which have exactly one or two intake valves per cylinder opening and thus, compared to the solution according to DE 10 2014 006 032 A1 (assuming a predetermined required total opening area), relatively large and therefore heavy intake valves. A preferred embodiment of the internal combustion engine according to the invention is therefore one in which exactly one or two intake valves are provided per cylinder opening, because this significantly reduces the design effort compared to the three intake valves according to DE 10 2014 006 032 A1.

[0018] The inventor further recognized that increased acoustic excitation resulting from a relatively high closing speed when the intake valve or valves engage is usually only perceived as disturbing in idling and overrun operation of the internal combustion engine, because it is masked by other operating and, in particular, combustion noises in other operating conditions, i.e., in a fired load operation of the internal combustion engine.Against this background, it is preferably provided that a drive system according to the invention further comprises a control device for the internal combustion engine by means of which an automated start-stop functionality for the internal combustion engine is implemented, wherein this automated start-stop functionality automatically stops or shuts down the internal combustion engine if no drive power (beyond idle power) is to be generated by it, and restarts automatically at least when corresponding drive power is to be generated by it. This ensures that the internal combustion engine is not operated at least most of the time when otherwise the relatively large acoustic excitation resulting from the relatively high closing speed when the intake valve(s) engage would be particularly disruptive.

[0019] It can preferably also be provided that the control device is designed such that a clutch, which is integrated into an output train of the drive system that also includes the crankshaft of the internal combustion engine, opens when the internal combustion engine has been stopped by means of the control device. This makes it possible to use the automated stop functionality even for so-called coasting of a motor vehicle according to the invention, in which it rolls or moves, with the drive wheels of the motor vehicle decoupled from the internal combustion engine. Consequently, undesirable acoustic excitations, which can result from the relatively high closing speed of the intake valve(s) when they come into contact with the engine, can also be avoided during such coasting operation of the motor vehicle.

[0020] In a motor vehicle according to the invention, which comprises at least one drive system according to the invention, it can in particular be a wheel-based and not rail-bound motor vehicle (preferably a passenger car or a truck). The drive system can in particular be designed to provide the (direct or indirect) propulsion power for the motor vehicle.

[0021] An automated start-stop function for the combustion engine can be particularly advantageous if the drive system is designed as a hybrid drive system and includes an electric traction motor that works in conjunction with the combustion engine, whereby the traction motor can provide drive power for the vehicle, at least temporarily. The drive system can also be configured such that the electric traction motor can provide the entire drive power for the vehicle, at least temporarily.During the operation of such a hybrid drive system, it may be provided that the combustion engine is automatically stopped relatively frequently and / or for relatively long periods. This can be used, in particular, to drive a vehicle powered by the hybrid drive system exclusively electrically or to utilize the deceleration of the vehicle by means of generator operation of the electric traction motor to generate electrical energy. If the combustion engine of such a hybrid drive system according to the invention were to continue operating during these relatively long periods, the relatively strong acoustic excitation that can result from the relatively high closing speed when the intake valve(s) come into contact could be perceived as particularly disturbing.

[0022] The internal combustion engine of a combustion engine according to the invention can, in particular, be a spark-ignition (e.g., by means of spark, high-energy, or pre-chamber ignition) and quantity-controlled gasoline engine, since the advantages resulting from a Miller or Atkinson combustion process can be particularly pronounced in such a gasoline engine. However, it is also possible that the internal combustion engine is a compression-ignition and quality-controlled diesel engine or a combination of a gasoline and diesel engine, i.e., an internal combustion engine with homogeneous compression ignition. The internal combustion engine can be operated with either liquid fuel (i.e., diesel or gasoline) or a gaseous fuel (in particular, natural gas, LNG, or LPG).

[0023] The invention is explained in more detail below with reference to an embodiment illustrated in the drawings. The drawings show, in some cases in a simplified representation: Fig. 1: a drive system according to the invention in a first embodiment; Fig. 2: an internal combustion engine of a drive system according to the invention, for example a drive system according to the Fig. 1, under supervision; Fig. 3: the internal combustion engine according to the Fig. 2 in a longitudinal section; Fig. 4: in a diagram, the valve lift curves of the intake and exhaust valves of an internal combustion engine according to the invention compared to the valve lift curves of a conventional internal combustion engine, as well as the fresh gas mass flows that flow into the combustion chambers of the internal combustion engines as a result of the opening of the intake valves; and Fig. 5: the lower section of the diagram according to the Fig. 4 with enlarged scaling of the vertical axes.

[0024] Fig. Figure 1 shows a schematic representation of a drive system according to the invention for a motor vehicle 1 (hybrid vehicle), which is not otherwise shown. Specifically, the drive system is designed as a hybrid drive system. This system comprises an electric machine, which is used temporarily as a traction motor 2, and an internal combustion engine 3. Drive power generated by the traction motor 2 and / or the internal combustion engine 3 is transmitted directly or indirectly to the wheels (not shown) of one or more driven axles of the motor vehicle 1. A coupling of the traction motor 2 and the internal combustion engine 3 (with respect to the drive effect for the motor vehicle 1), which is described in the Fig. The system, which is schematically represented by a shaft 4 in Figure 1, can be implemented in various ways. For example, the traction motor 2 can act directly on an output shaft (crankshaft) of the internal combustion engine 3, or via a transmission. Alternatively, drive power generated by the internal combustion engine 3 can be transmitted to the wheels of a first driven axle of the vehicle 1, while drive power generated by the traction motor 2 is transmitted to the wheels of a second driven axle of the vehicle 1.

[0025] The traction motor 2 is electrically connected to an energy storage device 5, which provides electrical energy on demand, for example with a battery and / or a fuel cell, thus supplying the traction motor 2 with electrical energy when it is to be operated as a motor. At the same time, it is also possible to operate the traction motor 2 as a generator, thereby producing electrical energy which can optionally be stored in the energy storage device 5.

[0026] Both the traction motor 2 and the internal combustion engine 3 can be controlled by means of a control device 6 (engine control unit). Control is effected in particular depending on the position of an accelerator pedal 7, which can be operated by a driver of the motor vehicle 1.

[0027] In the Fig. 2 and Fig. Figure 3 schematically represents an internal combustion engine with a combustion motor 3 for a drive system according to the invention, for example for a drive system according to the Fig. 1, shown. The internal combustion engine 3 can in particular be operated according to the Otto principle and can be designed accordingly.

[0028] The internal combustion engine 3, comprising a cylinder housing 8 and a cylinder head 9, forms several (e.g., four) cylinder openings 10. On the intake side, the cylinder openings 10 are connected to an intake manifold 11 of a fresh gas stream 12 of the internal combustion engine, and on the exhaust side, to an exhaust manifold 13 of an exhaust stream 14 of the internal combustion engine. In a known manner, fresh gas, consisting primarily of air, is combusted with fuel in combustion chambers 15, which are bounded by the cylinder openings 10 together with the pistons 16 guided therein and the cylinder head 9. The fuel can be introduced directly into the combustion chambers 15 by means of fuel injectors 17.

[0029] Alternatively, fuel can also be injected into the intake manifold 11. The exhaust gas produced during the combustion of the fuel-air mixture is discharged via the exhaust system 14.

[0030] The supply of fresh gas to the combustion chambers 15 and the removal of exhaust gas from the combustion chambers 15 is controlled via four gas exchange valves, in the present embodiment via two inlet valves 18 and two exhaust valves 20 per cylinder opening 26, wherein the gas exchange valves are controlled by a [unclear] in the Fig. 2 only partially and in the Fig. The valve train of the internal combustion engine 3, shown in further detail, is actuated.

[0031] The valve train comprises, according to the Fig. 3 a crankshaft 20, which forms crankpins 21, the crankpins 21 being connected to the pistons 16 via connecting rods 22. This converts the linear movements of the pistons 16 into a rotation of the crankshaft 20, the rotation of the crankshaft 20 in turn causing a periodic change of direction of the linear movements of the pistons 16. The rotation of the crankshaft 20 is also transmitted via a timing gear 23, for example a toothed belt drive, to two camshafts 24, each of which actuates two of the gas exchange valves for each combustion chamber 15. Of the camshafts 24, for example, one is configured as an intake camshaft, i.e., it actuates (directly or indirectly) all intake valves 18, while the other is configured as an exhaust camshaft and consequently actuates (directly or indirectly) all exhaust valves 19.

[0032] The internal combustion engine also includes an exhaust gas turbocharger (see below). Fig. 2) This system features a turbine 25 integrated into the exhaust gas stream 14 and a compressor 26 integrated into the fresh gas stream 12. A turbine impeller 25, driven by the exhaust gas flow, drives an impeller of the compressor 26 via a shaft 27. The resulting rotation of the compressor impeller 26 compresses the fresh gas passing through it. A wastegate 28 can be used to limit the boost pressure. Alternatively or additionally to turbocharging the combustion engine 3 by means of the exhaust gas turbocharger, (mechanical) turbocharging can also be achieved by means of a compressor driven in another way, for example by the combustion engine 3 itself or by means of an electric motor.

[0033] Furthermore, an exhaust aftertreatment device 29, for example in the form of a three-way catalytic converter and / or a particulate filter, is integrated into the exhaust stream 14. In addition, an exhaust gas recirculation line (not shown) connecting the exhaust stream 14 with the fresh gas stream 12 can be provided in a known manner to implement low-pressure or high-pressure exhaust gas recirculation.

[0034] During a fired load operation of the internal combustion engine 3, in which it provides drive power for the motor vehicle 1, the pistons 16 are moved oscillatingly between a top dead center (TDC) and a bottom dead center (BDC) due to the combustion processes in the individual combustion chambers 15. Because the internal combustion engine 3 is a four-stroke engine, the pistons 16 alternately perform a charge exchange stroke cycle and a power stroke cycle. The charge exchange stroke cycle of each piston 16 comprises an exhaust stroke of the respective piston 16 (corresponding to an exhaust stroke in the associated combustion chamber 15) and an intake stroke (corresponding to an intake stroke in the associated combustion chamber 15).The power stroke cycle comprises a compression stroke of the respective piston 16 (corresponding to a compression cycle in the associated combustion chamber 15) and a power stroke (corresponding to a power cycle in the associated combustion chamber 15). The four strokes of the pistons 16, or the four corresponding cycles of the cyclic processes occurring in the combustion chambers 15 during a fired load operation, correspond to one operating cycle that takes place in the respective combustion chamber 15 of the internal combustion engine 3.

[0035] The intake valves 18 and the exhaust valves 19 are opened and closed at defined timings by means of the camshafts 24 during fired load operation, as described in the Fig. 4 and Fig. Figure 5 shows a section of the rotation of the crankshaft 20 during an operating cycle. LW-OT denotes the top dead center in the movements of the individual pistons 16 during the respective charge exchange stroke cycle.

[0036] The diagram according to the Fig. Figure 4 shows a comparison between a conventional internal combustion engine with Miller combustion process and an internal combustion engine 3 according to the invention. Shown is, on the one hand (represented by dashed lines), a section of the (exhaust) valve lift curve 30, i.e., the course of the opening lift h (in mm) versus the rotation angle α of the crankshaft (°KW) with which the exhaust valves 19 are actuated. This valve lift curve 30 is identical for the two internal combustion engines being compared. Furthermore, the Fig. 4 each a section of the (intake) valve lift curves 31, 32, with which the intake valves 18 are actuated (thin lines). The intake valve lift curve 32 of the conventional internal combustion engine is shown with dashed lines and that (31) of the internal combustion engine 3 according to the invention with solid lines. And finally, the Fig. 4 The curves 33, 34 of the fresh gas mass flows ṁ (thick lines) that flow into the individual combustion chambers 15 of the internal combustion engines. Here too, the curve 34 of the conventional internal combustion engine is shown with dashed lines and that (33) of the internal combustion engine 3 according to the invention with solid lines.

[0037] The Fig. Figure 5 shows the lower section of the diagram according to the Fig. 4 with enlarged scaling of the vertical axes, on which, among other things, the opening stroke h is plotted.

[0038] In accordance with a Miller combustion process, the intake valves 18 of both internal combustion engines are closed relatively early, or significantly before bottom dead center (BDC). In the present embodiment, this occurs in a range between 490°C and 495°C or between BDC-50°C and BDC-45°C (relative to a residual lift h of one millimeter). At this point, the intake valve lift curve 31 of the internal combustion engine 3 according to the invention is shifted rearward, or late, by approximately 2°C compared to that of the conventional internal combustion engine. This shift generally applies to the intake valve lift curves 31 and 32 from the moment the individual intake valves 18 begin to lift off their respective valve seats. This shift persists until shortly before the individual intake valves 18 begin to seat on their respective valve seats, which occurs at a residual lift of 0.2 millimeters.From the beginning of the contact of the intake valves 18, the intake valve lift curve 31 of the internal combustion engine 3 according to the invention is significantly steeper than that of the conventional internal combustion engine (cf. the one in the . Fig. 5 (area marked with an ellipse), so that consequently the intake valves 18 of the internal combustion engine 3 according to the invention have significantly higher maximum and also average closing speeds upon contact than is the case with the intake valves of the conventional internal combustion engine. According to the invention, it is provided that the maximum closing speed of the intake valves 18 of the internal combustion engine 3 according to the invention is at least 0.36 m / s, preferably at least 0.5 m / s and particularly preferably at least 0.75 m / s at an operating speed of the internal combustion engine 3 or the crankshaft 20 of 4500 rpm. From the steeper course of the intake valve lift curve 31 of the internal combustion engine 3 according to the invention, it further follows that the contact of the intake valves 18 in the internal combustion engine 3 according to the invention is completed significantly earlier than in the conventional internal combustion engine. This leads to the fact that in the area of ​​the closing ramp, i.e.In the section of the respective intake valve lift curve 31, 32, which corresponds to the contact of the individual intake valves 18, a relevantly smaller amount of fresh gas flows into the respective combustion chamber. This can be compared to the corresponding section of the curves 33, 34 of the fresh gas mass flows ṁ, which is shown in the . Fig.4, which is characterized by the ellipse shown further to the right. Simultaneously, the fresh gas mass flow rate ṁ entering the combustion chambers 15 in the internal combustion engine 3 according to the invention is significantly larger before the intake valves 18 close (which occurs at a residual stroke of 1 mm). Consequently, the internal combustion engine 3 according to the invention, compared to the conventional internal combustion engine, is characterized by an earlier onset of the fresh gas flow into the combustion chambers 15. This earlier onset reduces the throttling losses in the internal combustion engine 3 according to the invention compared to the conventional internal combustion engine, since these losses are generally greater at smaller valve lifts than at larger valve lifts, depending on the respective fresh gas mass flow rate ṁ.In addition, this early shift in timing reinforces the effect sought by the Miller combustion process, particularly with regard to a reduction in the combustion chamber charge temperature and an improvement in the knocking tendency of the internal combustion engine 3. Reference symbol list 1 motor vehicle 2 electric traction motors 3 Internal combustion engine 4 wave 5 Energy storage device 6 Control device 7 Accelerator pedal 8 cylinder housing 9 cylinder head 10 Cylinder opening 11 Intake manifold 12 Fresh gas line 13 Exhaust manifold 14 Exhaust system 15 combustion chamber 16 pistons 17 Fuel injector 18 Inlet valve 19 Exhaust valve 20 Crankshaft 21 crank pins 22 connecting rods 23 Control gear 24 camshaft 25 Turbine 26 compressors 27th wave 28 Wastegate 29 Exhaust aftertreatment device 30 Exhaust valve lift curve of the internal combustion engine according to the invention and of the conventional internal combustion engine 31 Intake valve lift curve of the internal combustion engine according to the invention 32 Intake valve lift curve of the conventional internal combustion engine 33 Course of the fresh gas mass flow in the internal combustion engine according to the invention 34. Course of the fresh gas mass flow in the conventional combustion engine

Claims

[1] Drive system for a motor vehicle (1) with an internal combustion engine (3) having at least one cylinder opening (10) within which a reciprocating piston (16) is cyclically movable between a top dead center (TDC) and a bottom dead center (BDC), wherein the cyclic movement of the reciprocating piston (16) is coupled to a rotary movement of a crankshaft (20), wherein an inlet of fresh gas into the cylinder opening (10) can be controlled by means of exactly one inlet valve (18) or two inlet valves (18) per cylinder opening (10), which is / are actuated by means of a valve train, wherein the inlet valve (18) or the inlet valves (18) are opened and closed again in accordance with the course of a valve lift curve (31) when actuated,wherein the valve lift curve (31) depicts the course of the opening lift (h) of the inlet valve (18) or inlet valves (18) as a function of the rotation angle (α) of the crankshaft (20) and wherein the inlet valve (18) or inlet valves (18) is / are closed between BDC-150°KW and BDC-30°KW or between BDC+30°KW and BDC+150°KW, wherein at an operating speed of the internal combustion engine (3) of 4500 rpm the maximum closing speed when the inlet valve (18) or inlet valves (18) make contact is at least 0.36 m / s. [2] Drive system according to claim 1, characterized by , that at an operating speed of the internal combustion engine (3) of 4500 rpm the maximum opening speed when lifting the inlet valve (18) or the inlet valves (18) is at least 0.36 m / s. [3] Drive system according to one of the preceding claims, characterized bya control device (6) of the internal combustion engine (3) by means of which an automated start and stop functionality for the internal combustion engine (3) is implemented. [4] Drive system according to claim 3, characterized by , that the crankshaft (20) of the internal combustion engine (3) is part of a drive train of the drive system, wherein a clutch is integrated into the drive train and wherein the control device (6) is designed such that the clutch is opened when the internal combustion engine (3) is stopped by means of the control device (6). [5] Drive system according to any one of the preceding claims, characterized by an electric traction motor (2) that is in driving effect with the internal combustion engine (3). [6] Drive system according to one of the preceding claims, characterized by , that the internal combustion engine (3) is capable of being operated with external ignition and / or quantity control. [7] Motor vehicle with a drive system according to any one of the preceding claims.

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