EP2771582A1

EP2771582A1 - Crankshaft for a four-cylinder internal combustion engine and a four-cylinder internal combustion engine

Info

Publication number: EP2771582A1
Application number: EP12772995.2A
Authority: EP
Inventors: Rudolf Flierl
Original assignee: Entec Consulting GmbH
Current assignee: Entec Consulting GmbH
Priority date: 2011-10-27
Filing date: 2012-10-19
Publication date: 2014-09-03
Also published as: CN204061515U; WO2013060625A1; DE102011054881B3; DE102011054881B9

Abstract

The invention relates to a crankshaft for a four-cylinder internal combustion engine (2) having at least two bearing points (8) and four crank throws (36, 38, 40, 42), wherein a first and a second crank throw (36, 42) are offset from one another by an angle α = 120° and a third and a fourth crank throw (38, 40) are offset from one another by an angle ß = 0° to 15°, preferably an angle of 10°, wherein the first crank throw (36) and the third crank throw (38) are offset from one another by an angle γ = 105° to 120°, preferably an angle of 115° and the second crank throw (42) and the fourth crank throw (40) are offset from one another by an angle δ = 105° to 120°, preferably an angle of 115°.

Description

DESCRIPTION

Crankshaft for a four-cylinder internal combustion engine and a four-cylinder internal combustion engine

The invention relates to a crankshaft for a four-cylinder internal combustion engine having at least two bearing points and four crankshafts. Furthermore, the invention relates to a four-cylinder internal combustion engine having a crankcase and a crankshaft received therein with four crankshafts and a cylinder housing with four cylinders, wherein the cylinder housing is connected to a cylinder head, in the intake and exhaust valves and at least one camshaft for the intake valves and at least one cam are provided for the exhaust valves.

Such crankshafts, see for example GB 551 406 A and JP 2005 140 159 A, as well as four-cylinder internal combustion engines with such crankshafts are well known. In this case, the crankshaft in internal combustion engines converts the reciprocating movements of the pistons via connecting rods into rotational movements or moments. In the compressor stroke and in the exhaust stroke, the introduced rotational movement of the crankshaft ensures that the piston in the cylinder is again pressed in the opposite direction. In the known four-cylinder internal combustion engines, the crankshafts of the crankshafts are each offset by 180 ° from one another (see, for example, DE 200 80 161 U1). This has the consequence that the firing order corresponds to a clock of 180 °. Such an arrangement ensures the most uniform application of force to the crankshaft. In the course of lowering C0 ₂ emissions and optimizing the fuel consumption of internal combustion engines However, the drive concepts more complex to improve the efficiency of known engines. In the improvement of the most important in terms of the number of main engine, namely the supercharged four-cylinder engine, it has been found that a large deficit of this engine concept is to settle in the internal, unwanted exhaust gas recirculation between the Koiben. To prevent this, for example, in internal combustion engines, which are equipped with a fully variable valve train for the exhaust side, the Auslaßventilsteuerzeit be extremely shortened, but lo again led to losses in efficiency and emission limits. Another possible solution is the structural separation of the exhaust ducts up to the turbocharger. However, this leads again to additional costs in the production and manufacture of the internal combustion engine and also has a disadvantageous effect on the

15 required space and the weight of the engine.

The invention is thus based on the object to provide a crankshaft for a four-cylinder internal combustion engine or a four-cylinder internal combustion engine, which avoids the disadvantages mentioned above in a simple and cost-effective manner.

This object is achieved by a crankshaft in which a first and a second crank throw are offset by an angle of α = 120 ° to each other and a third and a fourth crank throw around a

25 angles of ß = 0 ° to 15 °, preferably offset by an angle of 10 ° to each other, wherein the first crank to the third crank throw by an angle γ of 105 ° to 120 °, preferably by an angle of 115 ° to each other are offset and the second crank throw to the fourth crank throw by an angle δ = 105 ° to

30 120 °, preferably offset by an angle of 115 ° to each other. Furthermore, the object is achieved by a four-cylinder internal combustion engine in which a first and a second crank throw are offset by an angle of α = 120 ° to each other and a third and a fourth crank throw by an angle of ß = 0 ° to 15 °, Preferably, at an angle of 10 °, are offset from one another, wherein the first crank are offset to the third crank throw by an angle γ of 105 ° to 120 °, preferably by an angle of 115 ° to each other and the second crank throw to the fourth crank throw by a Angle δ = 105 ° to 120 °, preferably offset by an angle of 115 ° to each other, wherein a firing order in the cylinders according to the angular intervals α, ß, γ, δ of the crankcurves is provided.

Both by the crankshaft and by a four-cylinder internal combustion engine incorporating such a crankshaft, it is now possible to operate a four-cylinder internal combustion engine such that a sufficiently long exhaust valve timing can be provided for each individual cylinder. As a result, internal exhaust gas recirculation, charge exchange losses and fuel consumption can be significantly optimized. In particular, with a load increase is a reduction of Ausschiebeverluste and the internally recycled residual gas amount important to optimize the combustion process. Due to the increased assenstromausstoß of exhaust gas in the exhaust gas exhaust stroke of the cylinders, which are associated with the third and fourth crank throw the crankshaft, the turbocharger receives a torque surge, which leads to a further improvement in the efficiency of the internal combustion engine. An offset of the third and fourth crank throw of up to 15 °, the mass flow behavior at the Abgasauslasstakt can optimize even further.

Furthermore, a variable valve drive device can advantageously be provided in the cylinder head. Also it is beneficial if in the lower load range cylinder deactivation of the cylinder, which is in operative connection with the third or fourth Kurbelkröpfung provided. This makes it possible to operate the Vierzyiinder internal combustion engine in the lower load range in the simplest way as a pure three-cylinder internal combustion engine with three equal displacement.

In this context, it may also be particularly advantageous if the variable valve device has an eccentric member which causes at least in one position a zero lift at least the inlet valves of the cylinder to be shut off. It should be noted that, of course, an eccentric can be provided which causes a zero lift of the exhaust valves.

The invention will be explained in more detail with reference to the following drawings. Hereby shows:

1 shows a schematic perspective view of a four-cylinder internal combustion engine with a crankshaft according to the invention,

Figure 2 is a schematic sectional view of the crankshaft according to the invention of Figure 1, and

Figure 3 is a torque-speed diagram.

Figure 1 shows in schematic form a perspective view of a four-cylinder internal combustion engine 2, which is operated as a four-cylinder in-line engine with four-stroke process. The four-cylinder internal combustion engine 2 essentially has a crankcase 4, in which a crankshaft 6 is rotatably mounted at five bearing points 8. The crankshaft 6 is connected via connecting rods 10 with pistons 12, 14, 16, 18 which are movable in respective cylinders 20, 22, 24, 26 in a known manner up and down. The four cylinders 20, 22, 24, 26 are in a cylinder housing 28 arranged. The cylinder housing is closed by a cylinder head 30, in which not shown inlet and outlet valves for the four cylinders 20, 22, 24, 26 are arranged in known manner. Schematically, two camshafts 32, 34 are shown, which act on the intake and exhaust valves.

The crankshaft 6 has crankshafts 36, 38, 40, 42, which are connected in a known manner with the connecting rods 10.

According to the invention, it is now provided that there is an asymmetrical distance between the crank cranks. This is particularly clear from the schematic view in Figure 2. In the present embodiment, the crankcases are arranged so that the crank 36 is offset with the crank 42 by an angle of α = 120 °. The crank throw 38 is offset with respect to the crank throw 40 at an angle of ß = 10 °. The crank throw 36 closes with the crank throw 38 an angle of γ = 105 ° and the crank throw 42 with the crank throw 40 also an angle of δ = 105 °. The firing order in the cylinders 20, 22, 24, 26, whether by auto-ignition in the diesel engine or by ignition spark in the gasoline engine, according to the angular distances of the crankshafts 36, 38, 40, 42. By this approach, it is possible to a classic four-cylinder Regarding the ignition sequence and the associated exhaust valve timing as a three-cylinder engine. This offers, as described above, great advantages in terms of emission and fuel consumption limit of such an engine.

FIG. 3 now shows a diagram in which the torque m is shown over the y-axis and the rotational speed n is shown over the x-axis. In this example, the upper line 44 shows the operation of the four-cylinder internal combustion engine according to the invention with all four operated cylinders. To further optimize the fuel consumption and thus the emission levels, it is of course possible to operate the engine over the entire engine speed range as a "true" three-cylinder engine, which is represented by the line 46. In terms of control, it is now natural in certain situations It is of course also conceivable to provide in the control that the internal combustion engine is operated with four cylinders in a certain speed range.

FIG. 3 now shows a diagram in which the torque m is shown over the y-axis and the rotational speed n is shown over the x-axis. In this example, the upper line 44 shows the operation of the four-cylinder internal combustion engine according to the invention with all four cylinders operated. In order to further optimize the fuel consumption and thus the emission values, it is of course possible to operate the engine over the entire engine speed range as a "true" three-cylinder engine, which is represented by the line 46.

Claims

PATENT APPLICATIONS

1. crankshaft for a four-cylinder internal combustion engine (2) having at least two bearing points (8) and four crankshafts (36, 38, 40, 42), characterized in that a first and a second crank throw (36, 42) by an angle of α = 120 ° offset from each other and a third and a fourth crank throw (38, 40) by an angle of ß = 0 ° to 15 °, preferably at an angle! are offset from each other by 10 °, wherein the first crank throw (36) to the third crank throw (38) by an angle γ of 105 ° to 120 °, preferably offset by an angle of 115 ° to each other and the second crank throw (42) to the fourth crank throw (40) by an angle δ = 105 ° to 120 °, preferably by a Winkef of 115 °, are offset from each other.

2. Four-cylinder internal combustion engine with a crankcase (4) and a crankshaft (6) housed therein with four crankshafts (36, 38, 40, 42) and a cylinder housing (28) with four cylinders (20, 22, 24, 26), wherein the cylinder housing (28) is connected to a cylinder head (30) in which intake and exhaust valves and at least one camshaft (32) for the intake valves and at least one camshaft (34) for the exhaust valves are provided, characterized in that a first and a second crank throw (36, 42) offset by an angle of α = 120 ° to each other and a third and a fourth crank throw (38, 40) by an angle of ß = 0 ° to 15 °, preferably by an angle of 10 °, wherein the first crank throw (36) to the third crank throw (38) by an angle γ of 105 ° to 120 °, preferably offset by an angle of 115 ° to each other and the second crank throw (42) to the fourth treatment belkröpfung (40) by an angle δ = 105 ° to 120 °, preferably offset by an angle of 115 ° to each other, wherein a firing order in the cylinders (20, 22, 24, 26) corresponding to the angular distances a, ß, Y, δ of the crank cranks (36, 38, 40, 42) is provided.

3. Four-cylinder internal combustion engine according to claim 2, characterized in that in the cylinder head (30) is provided a variable valve drive device.

4. Four-cylinder internal combustion engine according to claim 2 or 3, characterized in that in the lower load range, a cylinder deactivation of the cylinder (22, 24) which is in operative connection with the third or fourth crank throw (38, 40) is provided.

5. Four-cylinder internal combustion engine according to claim 3 and 4, characterized in that the variable valve device identifies an eccentric member which causes at least in one position a zero stroke at least the inlet valves of the cylinder to be shut off (22, 24).