DE102011001126A1 - Internal combustion engine has two camshafts, where one cam shaft is associated with intake valves of two cylinders standing in Vee-Row arrangement or VR arrangement to each other - Google Patents

Abstract

The internal combustion engine (1) has two camshafts (14,15), where one cam shaft is associated with intake valves of two cylinders (2,3) standing in a Vee-Row arrangement or VR arrangement to each other. Another camshaft is associated with the exhaust valves of the two cylinders. The two intake valves are associated with eccentric shafts that are adjustable by a common actuator.

Description

The invention relates to an internal combustion engine according to the one-part patent claim 1.

From the DE 10 2007 022 266 A1 is already known a variable valve lift. This is an intermediate lever on four line contacts. These line contacts consist of a camshaft, an eccentric shaft, a link and a rocker arm for a gas exchange valve. By means of the eccentric shaft, the valve lift can be adjusted. By means of the rotating camshaft, the gas exchange valve for the 4-stroke operation is opened and closed.

From the DE 103 146 83 A1 Another variable valve lift is known. The camshaft acts via the interposition of a push rod. In this valve lift adjustment, an adjustment bar is provided instead of an eccentric shaft.

From the EP 15 880 28 B1 is another variable valve lift is known in which the intermediate lever is not supported on a backdrop. Instead, the intermediate lever is pivotable about an axis displaceably mounted in the cylinder head.

From the DE 10 2004 001 343 A1 a variable valve lift is known, which is similar to the former DE 10 2007 022 266 A1 is executed. In addition, a motor for adjusting the eccentric shaft is shown.

The object of the invention is to provide a high-displacement, yet cost-effective and axially short-built internal combustion engine with a variable valve lift.

This object is achieved with the features of claim 1.

The invention may find application in a particularly advantageous manner in an internal combustion engine in VR construction. In such a design, two cylinders - in particular two cylinder banks - are basically in V arrangement. However, the angle between the two cylinders is so narrow that it comes very close to an in-line engine. This design allows a small crankpin distance due to the small offset of the cylinder. In addition, in contrast to the V-arrangement needs only a single cylinder block and a single cylinder head find application, which offers a cost advantage over the V-arrangement. In a further contrast to the V arrangement, each camshaft in the VR arrangement is assigned to either only the intake valves or only the exhaust valves of both cylinders and cylinder banks.

From the VR arrangement can be created with low development / manufacturing costs, an engine family with W engines, which are among the largest displacement combustion engines in the market of high-speed internal combustion engines. Such W motors are composed of several VR motors.

According to the invention, a valve lift adjustment is used, in which the adjustment takes place by means of an eccentric shaft. Thus, a total of four eccentric shafts are required for the entire internal combustion engine in order to adjust the two cylinder banks, each with at least one inlet valve and at least one outlet valve in the valve lift. For a cost-effective system, however, it may be sufficient to design only the inlet valves with regard to the valve lift variable. Thus, the turbulence of the fuel mixture is determined by the inlet flow area and the engine speed. A smaller inlet flow cross-section leads to a better turbulence of the fuel mixture and thus a more homogeneous combustion. In addition, with a variable valve lift on the intake valve, the valve opening timing can be shifted more toward "early" without the risk of the valve striking and breaking against the piston. Thus, the valve lift allows a very small to zero adjustable valve lift. In this case, only the inlet valves are variable with regard to the valve stroke, two eccentric shafts are sufficient. The shift of the valve opening time in the direction of "early" can be done in a particularly advantageous manner with a camshaft adjuster. With a variable valve lift adjustment can also be saved in gasoline engines, the throttle valve.

According to the invention, only one actuator is provided for the two eccentric shafts. This is particularly possible in the VR construction, since a structural design is possible in which a camshaft is assigned to two cylinders / cylinder banks, but only a single type of gas exchange valves - d. H. Inlet valves or exhaust valves - operated. The use of only one actuator for two eccentric shafts allows a cost-effective design.

In a particularly advantageous embodiment of the invention, the actuator in addition to a rotary motor or a linear motor and a self-locking gear, so that the displaced eccentric shaft can not reset automatically due to the high forces on the valve springs. In addition, such self-locking gear are provided with a high transmission ratio i, which allows a high torque at low engine torque or low engine power.

Further advantages of the invention will become apparent from the other claims, the description and the drawings.

The invention is explained in more detail with reference to several embodiments.

Show

1 schematically an internal combustion engine with two cylinder banks,

2 the valve train of the internal combustion engine 1 .

3 a plan view of the valve train according to 2 .

4 in a view only for a cylinder bank, a second embodiment of a valve train,

5 in a representation analog 4 a third embodiment of a valve train and

6 in a representation analog 4 a fourth embodiment of a valve train.

1 schematically shows an internal combustion engine 1 in which two cylinders 2 . 3 from two cylinder banks 4 . 5 in V-arrangement to each other. The two cylinders 2 . 3 in a common cylinder block are thus in a minor V-position, for example, at an angle α = 15 °. This makes it possible to reduce the crankpin distance from an in-line engine without the need for two cylinder blocks and cylinder heads. A common cylinder head 6 has an inlet on one side 7 for the fuel mixture and on the other side the manifold 8th with an outlet 9 for exhaust gases.

In the cylinder banks 4 . 5 arranged piston 11 . 12 drive in a manner customary for this type of engine to a crankshaft, not shown, along a geometric plane perpendicular to the plane of the drawing 10 is arranged. This crankshaft drives via a toothed belt drive 13 two camshafts 14 . 15 at. These are in coaxial with the camshafts 14 . 15 arranged driven pulleys 16 . 17 swiveling rotors 18 . 19 provided, which rotatably with the camshafts 14 . 15 are connected. Thus, the camshafts 14 . 15 opposite the timing belt wheels 16 . 17 adjustable in angle. Accordingly, this camshaft adjustment or valve timing adjustment by means of Flügelzellennockenwellenverstellern, which are also referred to as Schwenkmotorversteller.

Inside the cylinder head 6 are each camshaft 14 . 15 two variable valve lift adjusters 20 . 21 respectively. 22 . 23 assigned in 2 are more apparent.

The valve lift is done by means of four eccentric shafts 38 . 39 . 40 . 41 adjusted. As in 3 can be seen, it is the illustrated internal combustion engine 1 a six-cylinder engine with four gas exchange valves per cylinder. Thus, each cylinder has two intake valves and two exhaust valves. To two gas exchange valves of a kind with only one valve lift adjuster 20 respectively. 21 to operate, forks the valve lift adjuster 20 respectively. 21 over a fork lever 32 respectively. 33 on two gas exchange valves. In the following, the twelve valve lift adjusters will be simplified 20 to 31 based on the first valve lift 20 shown.

The valve lift adjuster 20 is here as the intake valves 34 . 35 executed gas exchange valves of the first cylinder 2 assigned. In the variable valve lift adjuster 20 becomes the inlet valve 34 by means of a first rocker arm 46 pressed or pressed in the open position, whereas a kraftemäßig opposite first valve spring 47 the inlet valve 34 in the closed position presses. The rocker arm 46 is pivotable about a geometric pivot axis. In addition, for the rocker arm 46 a hydraulic valve clearance compensation 48 intended. As a result of the valve clearance compensation 48 ensures that the rocker arm 46 on the one hand at an upper ram end 49 of the inlet valve 34 on the other hand on a two-dimensional working curve 50 a lever rests as an intermediate lever 52 is executed. This intermediate lever 52 is together with a second intermediate lever 53 the said fork lever 32 is affiliated and in 3 is shown in more detail. The fork lever 32 has four line contacts 58 to 61 over other components, so that also the position of the fork lever 32 by the displacement of the line contacts 58 to 61 is changeable. The line contacts 58 to 61 are doing with a housing-fixed backdrop 55 , the first eccentric shaft 38 , a cam 57 the first camshaft 14 and the first rocker arm 46 educated. The intermediate lever 52 is about a role 90 at the scenery 55 is supported by a rolling bearing. A rolling bearing has the intermediate lever 52 also opposite to that with another role 91 providing rocker arm 46 on.

Basically, the two intake valves 34 . 35 of the first cylinder 2 by the rotating at half the crankshaft speed camshaft 14 opened and closed. By pivoting or turning the eccentric shaft 38 is the degree of opening of these intake valves 34 . 35 set.

This is an actuator 62 provided that an electric motor 63 , two coaxial rotation on its drive shaft 73 arranged snails 71 . 72 and two of these driven worm wheels 65 . 66 includes. The two driven worm wheels 65 . 66 are each rotationally fixed with one of the two eccentric shafts 38 . 39 connected.

The electric motor 63 can for example be designed as a stepper motor. Here are the electric motor 63 , the drive shaft 73 and the two snails 71 . 72 at right angles to the two worm wheels 65 . 66 arranged. As a result of this arrangement, the axial space requirement of the internal combustion engine 1 relatively low, which is particularly advantageous in the VR-type engines and the W-motors based thereon, since these designs are chosen anyway with limited axial space.

The eccentric waves 38 . 39 rotate in this embodiment of the actuator 62 in the same direction.

In an alternative embodiment, a continuous screw may be arranged on the drive shaft.

4 shows an alternative embodiment to the actuator 62 in a view analog 2 , To simplify the illustration is only one actuator 82 for the first two eccentric shafts 38 . 39 shown. There is a snail 83 so between two coaxial rotation with the eccentric shafts 38 . 39 connected worm wheels 84 . 85 arranged that the snail 83 with both worm wheels 84 . 85 is engaged. As a result, the eccentric shafts rotate 38 . 39 in this embodiment of the actuator 83 in the same direction. The snail 83 is coaxial against rotation on a drive shaft 54 an electric motor 67 arranged at right angles to the eccentric shafts 38 . 39 or the worm wheels 84 . 85 is arranged. This saves the internal combustion engine 1 axial space. Since it is a worm gear with already elaborate gearing, the electric motor 67 even at an angle not equal to 90 ° - so for example 80 ° or 100 ° - to the eccentric shafts 38 . 39 be aligned. The optimum angle depends on the space conditions in the area of the cylinder head 6 from.

Across from 4 is yet another alternative embodiment conceivable, which is not shown in detail in the drawing. Across from 4 is still provided in this alternative embodiment, an additional gear stage. This additional gear stage can be designed as an offset gear for transmitting the rotational movement or with a translation. In particular, however, it can also have a reduction ratio with which a high rotational speed of the electric motor is translated into a low rotational speed with a relatively high torque. The two engaging in a screw small gears are designed with a helical toothing, in each of which engages a helical toothing of another large driven spur gear. Each of the other two large spur gears is coaxial and rotatably connected to one of the two eccentric shafts. The worm is arranged coaxially rotatably on a drive shaft of the electric motor, which is arranged at right angles to the eccentric shafts and the large spur gears. In particular, in this embodiment, the electric motor can also be aligned at an angle not equal to 90 ° - so for example 80 ° or 100 ° - to the eccentric shafts.

5 shows a further alternative embodiment in a similar view 4 , There is a coupling mechanism 92 for adjusting the eccentric shafts 38 . 39 Application. Each is a lever arm 75 . 76 with one of the two eccentric shafts 38 . 39 rotatably connected. These two lever arms 75 . 76 are the same length and at the lower end with a push rod 78 articulated. Will this push rod 78 transverse to the alignment of the eccentric shafts 38 . 39 shifted, so these two eccentric waves 38 . 39 pivoted about its axis. To initiate the adjusting force for the eccentric shafts 38 . 39 For example, a linear motor may be provided. This linear motor can be a hydraulic piston 79 be, which is adjusted via a differential pressure between two hydraulic pressures p1 and p2. In this embodiment, two joints 80 . 81 provided to the non-uniform movement of the push rod 78 for the hydraulic piston 79 to enable.

The eccentric rotate in this embodiment of the actuator 77 in the same direction.

It is also possible in an alternative embodiment, to actuate the push rod by means of an electric linear actuator. It is also possible to use a rotary electric motor, for example via an eccentric drive or a slotted guide.

6 shows a further alternative embodiment in a similar view 4 , In this case, an actuator comprises 96 a spur gear 97 and an electric motor 98 , These are coaxial and rotationally fixed on the eccentric shafts 38 . 39 spur gears 93 . 94 the same number of teeth and the same diameter are arranged, which mesh with each other and of a drive gear 95 are driven, which offset from the parallel electric motor 98 is driven.

Alternative to the toothed belt drive 13 For the so-called control drive can also be provided a chain drive or a duplex chain or a gear transmission.

As an alternative to the vane cell adjuster, an electric camshaft adjuster can also be used in particular.

The illustrated embodiments with the exception of 5 require very precisely ground gears or adjustability of the axial distance of the gears, to allow neither a large backlash nor to risk tensions or even jamming of the gears.

Consequently, a chain drive or a toothed belt drive for adjusting the eccentric shafts can also be used in particular. In a chain drive a chain tensioner is advantageous, which tensions both the load strand and the Zugtrum.

By means of this two-sided voltage prevents the two eccentric shafts over the life of the internal combustion engine against each other.

The representation of the valve train is partially simplified. In the DE 10 2004 001 343 A1 It can be seen that for the intermediate lever or the fork lever still a spring can be provided, which ensures that the intermediate lever is always applied even at the strong accelerations at high speeds to the four line contacts.

The valve lift adjuster can also be designed in such a way that rotates the eccentric shaft with camshaft speed.

There is no need to adjust intake valves and exhaust valves. Depending on the engine design, type of injection and design of the exhaust line, it may also be sufficient to carry out only the intake valves or only the exhaust valves with the variable with a single actuator valve lift.

It is also possible to use internal combustion engines which have more than two camshafts.

Instead of the rotary motors for the valve lift adjustment, which are shown here by way of example as electric motors, hydraulic vane-cell motors can also be used, as are known as vane-type camshaft adjusters or swivel motor adjusters of camshaft adjusters for changing the control times.

The described embodiments are only exemplary embodiments. A combination of the described features for different embodiments is also possible. Further, in particular not described features of the device parts belonging to the invention are to be taken from the geometries of the device parts shown in the drawings.

LIST OF REFERENCE NUMBERS

1

internal combustion engine

2

first cylinder

3

second cylinder

4

first cylinder bank

5

second cylinder bank

6

cylinder head

7

inlet

8th

elbow

9

outlet

10

axis

11

piston

12

piston

13

toothed belt drive

14

first camshaft

15

second camshaft

16

first toothed belt wheel

17

two toothed belt wheel

18

first swivel rotor

19

second tilt rotor

20

first valve lift adjuster

21

second valve lift adjuster

22

third valve lift adjuster

23

fourth valve lift adjuster

24

fifth valve lift adjuster

25

sixth valve lift adjuster

26

seventh valve lift adjuster

27

eighth valve lift adjuster

28

ninth valve lift adjuster

29

Tenth valve lift adjuster

30

eleventh valve lift adjuster

31

twelfth valve lift adjuster

32

first fork lever

33

second fork lever

34

first inlet valve first cylinder

35

second intake valve first cylinder

36

first exhaust valve first cylinder

37

second exhaust valve first cylinder

38

first eccentric shaft

39

second eccentric shaft

40

third eccentric shaft

41

fourth eccentric shaft

42

first intake valve second cylinder

43

second intake valve second cylinder

44

first exhaust valve second cylinder

45

second exhaust valve second cylinder

46

first rocker arm

47

first valve spring

48

Valve lash adjustment

49

upper ram end

50

working curve

51

geometric pivot axis

52

first intermediate lever

53

second intermediate lever

54

drive shaft

55

scenery

56

eccentric shaft

57

cam

58

first line contact

59

second line contact

60

third line contact

61

fourth line contact

62

actuator

63

electric motor

64

65

worm

66

worm

67

electric motor

68

69

70

71

slug

72

slug

73

drive shaft

74

75

first lever arm

76

second lever arm

77

actuator

78

pushrod

79

hydraulic pistons

80

first joint

81

second joint

82

actuator

83

slug

84

worm

85

worm

86

87

88

89

90

role

91

another role

92

coupling gear

93

spur gear

94

spur gear

95

drive gear

96

actuator

97

Spur gears

98

electric motor

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102007022266 A1 [0002, 0005]
• DE 10314683 A1 [0003]
• EP 1588028 B1 [0004]
• DE 102004001343 A1 [0005, 0043]

Claims (17)

Internal combustion engine ( 1 ) with two camshafts ( 14 . 15 ), of which the first camshaft ( 14 ) the inlet valves ( 34 . 42 ) of two - in particular in VR arrangement to each other - cylinders ( 2 . 3 ), whereas the second camshaft ( 15 ) the exhaust valves ( 37 . 45 ) of the two cylinders ( 2 . 3 ), wherein by means of two eccentric waves ( 38 . 39 . 40 . 41 ) adjustable valve lift adjuster ( 20 . 21 ) is provided, wherein the first eccentric shaft ( 38 ) the inlet valve ( 34 ) of the first cylinder ( 2 ) and the second eccentric shaft ( 39 ) the inlet valve ( 42 ) of the second cylinder ( 3 ), wherein the two of the inlet valves ( 34 . 42 ) associated eccentric shafts ( 38 . 39 ) by means of a common actuator ( 63 ) are adjustable. Internal combustion engine according to claim 1, characterized in that only the intake valves ( 34 . 42 ) are adjustable. Internal combustion engine according to claim 1, characterized in that a third eccentric shaft ( 40 ) the exhaust valve ( 37 ) of the first cylinder ( 2 ) and a fourth eccentric shaft ( 41 ) the exhaust valve ( 45 ) of the second cylinder ( 3 ), these two eccentric shafts ( 40 . 41 ) are adjustable by means of a common second actuator. Internal combustion engine according to claim 1, characterized in that the adjustable valve lift ( 20 . 21 ) swiveling intermediate lever ( 52 . 53 ), each of which is dedicated to one of the eccentric shafts ( 38 . 39 ) and - on one of these eccentric shafts ( 38 . 39 ), - on the camshaft ( 14 ), - on a component fixed to the housing and - indirectly via a working curve ( 50 ) at an inlet valve ( 34 ) is supported. Internal combustion engine according to claim 4, characterized in that the housing-fixed component is a backdrop ( 55 ) with a curve. Internal combustion engine according to claim 5, characterized in that the intermediate lever ( 52 ) about a roll ( 90 ) at the scenery ( 55 ) is supported by means of a rolling bearing. Internal combustion engine according to one of the preceding claims, characterized in that the camshaft ( 14 ) by means of a camshaft adjustment with respect to a driven by the crankshaft gear ( 16 ) is adjustable in angle, so that in addition to the valve lift and the valve timing of the intake valve and / or the exhaust valve is variable. Internal combustion engine according to one of the preceding claims, characterized in that the actuator in each case a transmission for transmitting power to the eccentric shafts ( 38 . 39 ). Internal combustion engine according to claim 8, characterized in that the transmission is self-locking. Internal combustion engine according to claim 9, characterized in that the transmission is an angular gear. Internal combustion engine according to claim 10, characterized in that the angular gear is a worm gear. Internal combustion engine according to claim 11, characterized in that coaxial and rotationally fixed on the eccentric shafts ( 38 . 39 ) Worm wheels ( 84 . 85 ) are arranged, which with a arranged between these common screw ( 83 ) are engaged. Internal combustion engine according to claim 12, characterized in that coaxial and rotationally fixed on the eccentric shafts ( 38 . 39 ) Worm wheels ( 65 . 66 ) are arranged, which with a screw ( 71 . 72 ) are engaged on a common shaft ( 73 ) of the rotary engine ( 63 ) executed actuator are arranged, wherein the shaft ( 73 ) at an angle of 90 ° to the eccentric shafts ( 38 . 39 ) is arranged. Internal combustion engine according to claim 8, characterized in that the transmission is a coupling gear ( 92 ). Internal combustion engine according to claim 8, characterized in that coaxial and rotationally fixed on the eccentric shafts ( 38 . 39 ) Spur gears ( 93 . 94 ) are arranged of the same diameter, which mesh with each other and by a drive gear ( 95 ) which can be driven by a parallel staggered motor ( 98 ) is driven. Internal combustion engine according to one of the preceding claims, characterized in that each of the two cylinders ( 2 . 3 ) a cylinder bank ( 4 . 5 ) is associated. Internal combustion engine according to claim 16, characterized in that the internal combustion engine has two further cylinder banks arranged in VR arrangement to one another, so that a W arrangement results.

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