US 20120210960A1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2012/0210960 A1 KIRCHWEGER et al. (43) Pub. Date: Aug. 23, 2012

(54) INTERNAL COMBUSTION ENGINE HAVING Publication Classi?cation EIGHT CYLINDERS IN A V-CONFIGURATION (51) Int‘ Cl‘ F01L 1/34 (2006.01) F01L 1/00 (2006.01) (75) Inventors: Wolfram KIRCHWEGER, F01 L 1/24 (200601) Muenchen (DE); Ralf Kad‘lras (52) us. Cl...... 123/9015; 123/901; 123/9046 Landshut (DE) (57) ABSTRACT (73) AssigneeZ Bayerische Motoren Werke An internal combustion engine having eight cylinders in Aktiengesellschaft: Muenchen V-con?guration, Wherein a ?rst cylinder bank and a second (DE) cylinder bank are disposed opposite one another. The internal combustion engine includes a cross-plane crankshaft and has (21) Appl. No.: 13/462,447 a ?ring order of a 900 crank angle from cylinder to cylinder. An intake camshaft and an exhaust camshaft are associated (22) Filed; May 2 , 2012 With each cylinder bank for actuating at least one intake gas exchange Valve and one exhaust gas exchange Valve for each Related U_s_ Application Data cylinder. The gas exchange intake Valves that are actuated at a 900 crank angle in the same cylinder bank have a larger (63) Continuation of application NO~ PCT/EP2010/ Valve stroke than the gas exchange intake Valves in same 006122: ?led on Oct 7: 2010- cylinder bank actuated immediately prior thereto. The gas exchange intake Valves in the same cylinder bank actuated (30) Foreign Application Priority Data immediately prior thereto have a smaller Valve stroke than all the remaining gas exchange intake Valves of both cylinder Nov. 13, 2009 (DE) ...... 10 2009 053 269.2 banks 1:11;? @211: 180"

180°

90“ t t Patent Application Publication Aug. 23, 2012 US 2012/0210960 A1

180° 220° 180“ 90°

180° 270°

?rings?quence ::1-5-~4~8-6»-3—7-2

1 1 80° L0. I180" I270" US 2012/0210960 A1 Aug. 23, 2012

INTERNAL COMBUSTION ENGINE HAVING bank and are actuated according to a 900 crank angle in the EIGHT CYLINDERS IN A same cylinder bank, have a larger valve lift than the intake gas V-CONFIGURATION exchange valves in the same cylinder bank actuated immedi ately prior thereto. The intake gas exchange valves in the CROSS-REFERENCE TO RELATED same cylinder bant actuated immediately prior thereto have a APPLICATIONS smaller valve lift than all of the remaining intake gas exchange valves of both cylinder banks. [0001] This application is a continuation of PCT Interna [0006] This further development according to the invention tional Application No. PCT/EP20l0/006 l 22, ?led Oct. 7, makes it possible to attain in an advantageous Way an equal 2010, Which claims priority under 35 U.S.C. §1 19 from Ger iZation of the speci?c Work of the individual cylinders in each man Patent Application No. DE 10 2009 053 269.2, ?led Nov. cylinder bank and, thus, to reduce the rotational irregularity in 13, 2009, the entire disclosures of Which are herein expressly the critical operating ranges, in particular in neutral and in the incorporated by reference. loWer partial load range. OWing to this inventive measure the use of applied measures can be avoided, a state that leads to an BACKGROUND AND SUMMARY OF THE improvement in the e?iciency (less fuel consumption and/or INVENTION CO2 emission), the smooth running and raW pollution emis [0002] The invention relates to an internal combustion sion. In addition, the improved smooth running makes it engine having eight cylinders in a V-con?guration Wherein a possible to loWer the idling speed and, as a result, leads to a ?rst, a second, a third and a fourth cylinder, arranged side reduction in the idling fuel consumption. by-side in series, form a ?rst cylinder bank; and a ?fth, a sixth, [0007] In a ?rst preferred exemplary embodiment, the a seventh and an eighth cylinder, arranged side-by-side in intake gas exchange valves are actuated via one intermediate series, form a second cylinder bank, Which lies opposite the element each. The larger valve lift occurs by Way of a lift ?rst cylinder bank. correction of the intermediate element. The intermediate ele [0003] German Published Patent Application DE 199 54 ment may be, for example, a drag or rocking lever. 689Al discloses a generic internal combustion engine having [0008] In a second preferred exemplary embodiment, the eight cylinders in a V-con?guration. A ?rst, a second, a third intermediate element is supported at the cylinder head on a and a fourth cylinder arranged side-by-side in series form a play compensating element. The larger valve lift occurs by ?rst cylinder bank; and a ?fth, a sixth, a seventh and an eighth Way of a height and/or angular position correction of the play cylinder also arranged side-by-side in series form a second compensating element. The play compensating element may cylinder bank opposite the ?rst cylinder bank. Furthermore, be, for example, a hydraulic play compensating element. the internal combustion engine has a crankshaft With a 900 [0009] In a third preferred exemplary embodiment, the bend, that is, a cross-plane crankshaft, and an ignition interval intake gas exchange valves are actuated by Way of a variable of 900 crank angle (900 CA) from cylinder to cylinder. For the lift valve timing mechanism With a lift adjustment element. charge cycle each cylinderbankhas an intake camshaft and an The larger valve lift occurs by Way of a lift correction of the exhaust camshaft in order to actuate the intake gas exchange lift adjustment element. valves and the exhaust gas exchange valves for each cylinder. [0010] Particularly preferably, the larger and/or the smaller In order to improve, inter alia, the smooth running of the lift height ranges from 0.005 mm to 1.0 mm With respect to internal combustion engine, in particular in neutral and under the remaining intake gas exchange valves. This preferred smaller partial loads, it is proposed to provide means for range of values particularly achieves the inventive effect. implementing differing exhaust valve lift progressions of at [0011] Other objects, advantages and novel features of the least tWo cylinders arranged in one cylinder roW in order to present invention Will become apparent from the folloWing reduce the overlapping opening phases of these exhaust gas detailed description of one or more preferred embodiments exchange valves. In this context the intake valve and the When considered in conjunction With the accompanying exhaust valve of one of the tWo cylinders are themselves in an draWings. overlapping opening phase. [0004] Even if this prior art internal combustion engine BRIEF DESCRIPTION OF THE DRAWINGS With eight cylinders in V-con?guration does not have, in [0012] FIG. 1 shoWs in schematic form a ?ring sequence principle, any draWbacks, the object of the present invention for a generic internal combustion engine With eight cylinders is to provide an additional measure to reduce the rough run in a V-con?guration; ning of the internal combustion engine, in particular, in neu [0013] FIG. 2 shoWs in schematic form a generic internal tral and in the loWer partial load range. combustion engine With eight cylinders in V-con?guration. [0005] This and other objects are achieved by an internal combustion engine With eight cylinders in V-con?guration, DETAILED DESCRIPTION OF THE DRAWINGS Wherein a ?rst, a second, a third and a fourth cylinder, arranged side-by-side in series, form a ?rst cylinderbank; and [0014] In both ?gures, like reference numerals apply to a ?fth, a sixth, a seventh and an eighth cylinder, arranged identical components. side-by-side in series, form a second cylinderbank, Which lies [0015] FIG. 1 shoWs in schematic form a ?ring sequence opposite the ?rst cylinder bank. The internal combustion for a generic internal combustion engine With eight cylinders engine has a cross-plane crankshaft and an ignition interval of in V-con?guration. The cylinders are shoWn in symbolic form 900 crank angle from cylinder to cylinder. Each cylinder bank as spheres and are numbered in sequence from 1 to 8 accord has an intake camshaft and an exhaust camshaft in order to ing to the cylinder number. The ?rst, the second, the third and actuate at least one intake gas exchange valve and one exhaust the fourth cylinder 1, 2, 3, 4 are arranged side-by-side in a ?rst gas exchange valve for each cylinder. The intake gas cylinder roW, as shoWn in FIG. 2, and form a ?rst cylinder exchange valves of the cylinders, Which form each cylinder bank 9. The ?fth, the sixth, the seventh and the eighth cylinder US 2012/0210960 A1 Aug. 23, 2012

are arranged side-by-side in a second cylinder roW and form intake valve lifts corrects the differing Work of the individual a second cylinder bank 10, Which lies opposite the ?rst cyl cylinders 1, 2, 3, 4, 5, 6, 7, 8. As a result, in critical operating inder bank 9. In addition, the internal combustion engine has points the above described, system dependent rotational a cross-plane crankshaft, Which results in an ignition interval irregularities are totally eliminated from theV8 typical charge of 90° crank angle from cylinder to cylinder. Furthermore, cycle in the ideal case. That means that the intake gas each cylinder bank 9, 10 has an intake camshaft (not illus exchange valves of the cylinders 1, 2, 3, 4, 5, 6, 7, 8 With less trated) and an exhaust camshaft (also not illustrated) in order speci?c Work are opened to a greater degree; the intake gas to actuate at least one intake gas exchange valve and at least exchange valves of the cylinders 1, 2, 3, 4, 5, 6, 7, 8 With one exhaust gas exchange valve for each cylinder. higher speci?c Work are opened to a lesser degree. For the [0016] The ?ring sequence for the internal combustion technical implementation three different embodiments are engine conforming to its genre runs: cylinder 1-cylinder proposed: 5-cylinder 4-cylinder 8-cylinder 6-cylinder 3-cylinder 7-cyl [0023] 1 . that the intake gas exchange valves be actuated by inder 2, and then repeats from the beginning. The schematic Way of one intermediate element each and that the larger diagram shoWs this ?ring sequence With internal straight valve lift occurs by Way of a lift correction of the intermediate arroWs from cylinder to cylinder. In addition, the ignition element, Which can be preferably a drag or rocking lever. interval in degree of crank angle (deg. CA) of the cylinders of [0024] 2. that the intermediate element be supported at the each cylinder bank 9, 10 are shoWn by external, curved cylinder head on a play compensating element and that the arroWs. Due to the irregular ?ring sequence With respect to a larger valve lift occurs by Way of a height and/or angular cylinder bank 9, 10, the ignition intervals from cylinder to position correction of the play compensating element; cylinder amount to 90° or 180° or 270° crank angle. A re-start Wherein the play compensating element is even more prefer of the ?ring sequence is shoWn by a vertical dotted line. ably a hydraulic play compensating element. [0017] Working on the above basis, the result of the illus [0025] 3. that the intake gas exchange valves be actuated by trated, irregular ?ring sequence in V8 internal combustion a variable lift valve timing mechanism With a lift adjustment engines With a cross-plane crankshaft is a mutual interference element and that the larger valve lift occur by Way of a lift effect among the cylinders 1, 2, 3, 4, 5, 6, 7, 8 oWing to the gas correction of the lift adjustment element. Such a variable lift dynamics in both an air accumulator and in an exhaust gas valve timing mechanism is knoWn, for example, from DE 101 manifold. The maximum mutual interference effect takes 23 186 A1 and may be found in all BMW engines having the place inside a cylinder bank 9, 10 betWeen the cylinders 1, 2, so-called Valvetronic technology. In this case the lift of the 6, 8 With 90° ignition interval each and generates for reasons gas exchange valves of the individual cylinders 1, 2, 3, 4, 5, 6, of the gas dynamics a differing fresh gas ?lling, charge cycle 7, 8 can be corrected, for example, by a variety of control Work and residual gas content and, thus, a differing cylinder cams for each position of an eccentric shaft that conforms to speci?c Work. Especially in neutral and in the partial load its genre, so that there is the possibility of an optimiZation for range, the results are rotational irregularities, Which in the a multiplicity of operating points. past Were minimized as much as possible by applied mea [0026] FIG. 2 shoWs in schematic form a generic internal sures. combustion engine With eight cylinders in V-con?guration. [0018] Typical are the folloWing measures: The individual cylinders 1, 2, 3, 4, 5, 6, 7, 8 are once again [0019] 1. Cylinder selective ignition timing: All of the cyl shoWn in symbolic form as spheres. The cylinders 1, 2, 3, 4 lie inders 1,2,3, 4,5, 6, 7,8 ofa bank 9,10 are moved to the level side-by-side in a roW and form the ?rst cylinder bank 9. The of the Worst cylinder by retarding the ignition timing. As a cylinders 5, 6, 7, and 8 also lie side-by-side in a roW and form result, the overall ef?ciency deteriorates in a disadvantageous the second cylinder bank 10, so that the second cylinder bank 10 lies opposite the ?rst cylinder bank 9. The ?rst cylinder Way. [0020] 2. Cylinder selective mixture pilot control: The cyl bank 9 has a ?rst air accumulator 11; and the second cylinder bank 10 has a second air accumulator 12. The How direction inders are put on a uniform level by a targeted enriching or of the incoming air is shoWn in schematic form by arroWs. In leaning (7», #l) of the cylinders. The draWback With this strat addition to the air accumulators 11, 12, the ignition interval of egy is that the overall ef?ciency of the internal combustion the individual cylinders of the respective bank 9, 10 is shoWn engine decreases, the smooth running of the leaned cylinders once again in schematic form by arroWs. deteriorates, and the raW pollutant emission increases. [0027] The further development according to the invention [0021] 3. Selective throttling: In order to reduce the rota makes it possible to attain an equaliZation of the speci?c Work tional irregularities, the lift in the case of a variable intake of the individual cylinders 1, 2, 3, 4, 5, 6, 7, 8 and, thus, a valve lift can be enlarged; and the load can be reduced again reduction in the rotational irregularity in critical operating by Way of the throttle ?ap. The disadvantageous results are a ranges, in particular, in neutral and in the partial load range. degradation of the ef?ciency of the internal combustion [0028] This feature results in an advantageous Way in the engine and, thus, a Worsening of the fuel consumption. folloWing: [0022] In order to eliminate the aforementioned draW [0029] (a) avoidance of the use of applied measures and, backs, according to the invention the intake gas exchange thus, an improvement in the ef?ciency of the internal com valves of those cylinders (1, 2, 3, 4, 5, 6, 7, 8) that form a bustion engine (fuel consumption and/or CO2 emission), the cylinder bank (9, 10) and that are actuated according to a 90° smooth running, and raW pollution emissions; and crank angle in the same cylinder bank (9, 10) have a larger [0030] (b) loWering of the idling speed for reasons of valve lift than the just previously actuated intake gas improved smooth running, a feature that leads to a reduction exchange valves in the same cylinder bank (9, 10); and the just in the idling fuel consumption. previously actuated intake gas exchange valves in the same cylinder bank (9, 10) have a smaller valve lift than all of the LIST OF REFERENCE NUMERALS remaining intake gas exchange valves of both cylinder banks [0031] 1. ?rst cylinder (9, 10). This means that a targeted adaptation of the individual [0032] 2. second cylinder US 2012/0210960 A1 Aug. 23, 2012

[0033] 3. third cylinder 3. The internal combustion engine according to claim 2, [0034] 4. fourth cylinder Wherein the respective intermediate element is one of a drag [0035] 5. ?fth cylinder and rocking lever. [0036] 6. sixth cylinder 4. The internal combustion engine according to claim 2, [0037] 7. seventh cylinder Wherein the intermediate element is supported at a cylinder [0038] 8. eighth cylinder head on a play compensating element, and further Wherein the [0039] 9. ?rst cylinder bank larger valve lift occurs by Way of at least one of a height and [0040] 10. second cylinder bank angular position correction of the play compensating ele [0041] 11. ?rst air accumulator ment. [0042] 12. second air accumulator 5. The internal combustion engine according to claim 3, [0043] The foregoing disclosure has been set forth merely Wherein the intermediate element is supported at a cylinder to illustrate the invention and is not intended to be limiting. head on a play compensating element, and further Wherein the Since modi?cations of the disclosed embodiments incorpo larger valve lift occurs by Way of at least one of a height and rating the spirit and substance of the invention may occur to angular position correction of the play compensating ele persons skilled in the art, the invention should be construed to ment. include everything Within the scope of the appended claims 6. The internal combustion engine according to claim 4, and equivalents thereof. Wherein the play compensating element is a hydraulic play What is claimed is: compensating element. 1. An internal combustion engine, comprising: 7. The internal combustion engine according to claim 5, eight cylinders in a V-con?guration, Wherein a ?rst, a sec Wherein the play compensating element is a hydraulic play ond, a third and a fourth cylinder arranged side-by-side compensating element. in series form a ?rst cylinder bank, and Wherein a ?fth, a 8. The internal combustion engine according to claim 1, sixth, a seventh and an eighth cylinder arranged side-by further comprising a variable lift valve timing mechanism by side in series form a second cylinder bank lying opposite Which the intake gas exchange valves are actuated, the vari the ?rst cylinder bank; able lift valve timing mechanism having a lift adjustment a cross-plane crankshaft, the internal combustion engine having an ignition interval of 90° crank angle from cyl element; and inder to cylinder; Wherein the larger valve lift occurs by Way of a lift correc each cylinder bank having an intake camshaft and an tion of the lift adjustment element. exhaust camshaft in order to actuate at least one intake 9. The internal combustion engine according to claim 1, gas exchange valve and one exhaust gas exchange valve Wherein at least one of the larger and the smaller lift height for each cylinder; ranges from 0.005 mm to 1.0 mm With respect to the remain Wherein the intake gas exchange valves of the cylinders ing intake gas exchange valves. forming each cylinder bank actuated according to a 900 10. The internal combustion engine according to claim 2, crank angle in the same cylinder bank have a larger valve Wherein at least one of the larger and the smaller lift height lift than the intake gas exchange valves in the same ranges from 0.005 mm to 1.0 mm With respect to the remain cylinder bank actuated immediately prior thereto; and ing intake gas exchange valves. Wherein the intake gas exchange valves in the same cylin 11. The internal combustion engine according to claim 4, der bank actuated immediately prior thereto have a Wherein at least one of the larger and the smaller lift height smaller valve lift than all of the remaining intake gas ranges from 0.005 mm to 1.0 mm With respect to the remain exchange valves of both cylinder banks. ing intake gas exchange valves. 2. The internal combustion engine according to claim 1, 12. The internal combustion engine according to claim 8, further comprising intermediate elements, each intermediate Wherein at least one of the larger and the smaller lift height element respectively actuating one of the intake gas exchange ranges from 0.005 mm to 1.0 mm With respect to the remain valves; and ing intake gas exchange valves. Wherein the larger valve lift occurs by Way of a lift correc tion of the respective intermediate element. * * * * *