WO2012116854A1

WO2012116854A1 - Method for controlling an internal combustion engine

Info

Publication number: WO2012116854A1
Application number: PCT/EP2012/050277
Authority: WO
Inventors: Sascha Ambrock; Friedrich Boecking; Frank Zehnder
Original assignee: Robert Bosch Gmbh
Priority date: 2011-03-01
Filing date: 2012-01-10
Publication date: 2012-09-07
Also published as: EP2681432B1; CN103415689A; EP2681432A1; CN103415689B; DE102011004902A1

Abstract

Method for controlling an internal combustion engine having at least one piston which is fastened to a crankshaft in an articulated manner, and having a common-rail injection system having a high-pressure pump with a pump camshaft (3) which has at least one cam (4), and at least one pump plunger (7) which interacts with the pump camshaft (3) via a roller tappet (5). According to the invention, a method for controlling an internal combustion engine is specified, by way of which method the wear behaviour and the operating behaviour of the internal combustion engine are improved. This is achieved by the fact that the angular offset of the pump camshaft (3) with respect to the crankshaft is designed with regard to operation of the internal combustion engine which is minimized in terms of wear and optimized in terms of operation.

Description

description

Title:

Method for controlling an internal combustion engine

The invention relates to a method for controlling an internal combustion engine having at least one piston pivotally attached to a crankshaft and a common rail injection system, comprising a high-pressure pump with a pump camshaft having at least one cam and at least one pump cylinder cooperating with the pump node shaft via a roller tappet.

State of the art

Such a method for controlling an internal combustion engine is known from DE 10 2010 001 725 A1. This method is designed so that, especially in internal combustion engines, which are installed in motor vehicles and which are provided with a start-stop / restart system, to ensure stability when starting the internal combustion engine. In this case, the control method described is designed so that a deviation of a time is required, which is required to start the internal combustion engine. For this purpose, in particular a throttle valve is present, which is opened or closed in order to control an air supply to the internal combustion engine. This throttle valve is controlled according to a complex algorithm.

The invention has for its object to provide a method for controlling an internal combustion engine, with which the wear behavior and the performance of the internal combustion engine can be improved.

Disclosure of the Invention Advantages of the Invention

This object is achieved in that the angular offset of the pump camshaft to the crankshaft with respect to a wear-minimized and operationally optimized drive the internal combustion engine is designed. This angular offset of the pump camshaft to the crankshaft has an influence on the injection insofar as this angular offset has an influence on the refilling process of a high-pressure accumulator in relation to that of the fuel! has ejected fuel. Furthermore, the angular offset has a direct influence on the occurring in the high-pressure pump

Lagerkräfte and a drive of the high pressure pump by, for example, a chain on the chain forces. Thus, the angular displacement improves the operating behavior of the internal combustion engine and minimizes wear. In a further development of the invention, the angular offset is optimized with regard to the operation of the injection system. And in a further embodiment, the angular offset is optimized, in particular with regard to the mechanical load of the injection system. Depending on the design, configuration and number of cylinders of the internal combustion engine, different wrench offsets result here.

For example, such an angular offset is 39 ° in a four-cylinder series internal combustion engine. This means that the high pressure pump always 39 ° before the engine cylinder TDC (OT = top dead center) promotes and therefore always 39 ° after engine cylinder TDC is. In this case, the high-pressure pump is designed as a so-called one-punch pump and the associated pump camshaft has two cams. The associated transmission ratio between the crankshaft and the pump camshaft is i = 1.

In a V-type six-cylinder internal combustion engine, the angular displacement of the pump camshaft with respect to the crankshaft is 16.36 °, the high-pressure pump always conveying 16.36 ° relative to the engine crankshaft TDC, and thus with respect to the angular position of the pump camshaft. Cylinder OT is always 16.36 ° before the engine cylinder TDC stands. In such an internal combustion engine, the high-pressure pump is designed as a two-piston pump, wherein the two punches (pump plungers) enclose an angle of 90 °. The pump camshaft in this embodiment also has two cams and is driven with a gear ratio of i = 3/4 of the crankshaft of the internal combustion engine. Both interpretations optimize or minimize the overall mechanical load on the injection system.

In a further development of the invention takes place at a fixed Wnkellage the start and / or stop of the internal combustion engine at a crankshaft angle, for the operation the injection system is optimized. In this case, the operation can be optimized, for example, with regard to the occurring forces and / or the wear behavior.

In a further embodiment of the invention, the start and / or stop of the internal combustion engine take place at a crankshaft angle at which the at least one cam of the pump camshaft is in the range outside one above an upper or lower dead center of the roller tappet. It should be noted that in the area of the top and bottom dead center, the risk of a ram in the high-pressure pump is greatest. According to the invention, these ranges, which are at -5 ° to + 5 °, 85 ° to 95 °, 175 ° to 185 ° and 265 ° to 275 ° (PNW), are avoided.

Thus, in a four-cylinder in-line engine, inferior angular positions of the crankshaft are 51 ° ± 5 °, 141 ° ± 5 °, 231 ° ± 5 °, 321 ° ± 5 °, 41 1 ° ± 5 °, 501 ° ± 5 ° and 681 ° ± 5 ° (KW). In a V-type six-cylinder internal combustion engine, unfavorable crankshaft rotational angular positions are 51 ° ± 5 °, 141 ° ± 5 °, 231 ° ± 5 °, 321 ° ± 5 °, 411 ° ± 5 °, 501 ° ± 5 ° and 681 ° ± 5 ° (KW).

In a further development of an internal combustion engine electronics stops at a stop command, the crankshaft at a predetermined crankshaft angle, which avoids the previously specified areas. This stopping process can take place in that, depending on operating parameters of the internal combustion engine and the high-pressure pump, the stop command of, for example, an automatic start-stop system of the internal combustion engine is converted at a crankshaft angle, which the internal combustion engine electronics know after reaching this crankshaft angle rotates certain rotation angle and then comes to a standstill. Optionally, an auxiliary device, such as a starter for targeted braking of the crankshaft can be used by the starter is used in this operating condition as a brake. In a further development of the invention, the internal combustion engine electronics by means of a

Auxiliary device at a stop command and / or start command, the crankshaft to a predetermined crankshaft angle, which also avoids the previously specified areas. If the internal combustion engine runs so that the crankshaft and thus the pump camshaft are in an unfavorable rotational position, the crankshaft is rotated further until a favorable angular position of the pump camshaft is reached. This can in turn be done for example by the controlled use of the starter during the stop process or during the subsequent startup of the internal combustion engine. Further advantageous embodiments of the invention are shown in the drawing, are described in more detail in the embodiments illustrated in the figures of the invention.

Brief description of the drawings In the drawings:

1 is a schematic representation of a section through a high-pressure pump designed as a stamping pump,

FIG. 2 diagrammatically shows disadvantageous stop positions for a four-cylinder internal combustion engine, FIG.

Fig. 3 is designed as a two-stamp pump high-pressure pump and

Fig. 4 in diagram form disadvantageous stop positions for a six-cylinder V-type internal combustion engine.

Embodiments of the invention

The high-pressure pump 1 according to FIG. 1 is designed as a stamping pump and has a pump housing 2 by a pump camshaft 3 is rotatably mounted. The pump camshaft 3 has two opposing cams 4. On the cam track thus formed runs a roller tappet 5 with a roller 6 from. The roller 6 is rotatably mounted in a roller shoe of the roller tappet 5 and converts the rotational movement of the pump camshaft 3 in a translational up and down movement of the roller tappet 5. With the roller tappet 5 a pump plunger 7 cooperates, of a plunger 8 against the roller tappet 5 is pressed. The pump plunger 7 is guided in a cylinder and cooperates with a working space, is introduced into the controlled fuel. This introduced into the working space fuel is conveyed in a pumping movement of the pump plunger 7 in a high-pressure accumulator, from which the fuel stored there under a pressure of up to about 3,000 bar fuel injectors is selectively removed and injected into associated combustion chambers of the internal combustion engine. The high-pressure pump 1 shown in FIG. 1 is designed for a four-cylinder internal combustion engine and is driven by the crankshaft of the internal combustion engine with a transmission ratio i = 1. In the illustrated embodiment, the pump camshaft 3 is at the rotational angle 0 ° PNW with respect to the roller tappet 5 or the roller 6, wherein the rotation angle 90 °, 180 ° and 270 ° (PNW) are additionally entered in Fig. 1. Between the pump camshaft 3 and the crankshaft of the internal combustion engine, an angular offset of 39 ° is provided in the form that the high-pressure pump always 39 ° before the engine cylinder TDC promotes and therefore at the engine cylinder TDC always 39 ° after the combustion engine cylinder TDC stands. The internal combustion engine according to the invention is turned off so that the rotational angle position (and rotational angle positions given below) of the pump camshaft 1 shown in FIG. 1 is not taken. These are the ranges -5 ° to + 5 °, 85 ° to 95 °, 175 ° to 185 ° and 265 ° to 275 ° (PNW). For the internal combustion engine, there are thus disadvantageous parking positions relative to the crankshaft, which are shown or reproduced in FIG. The lower degree scale shows the pump camshaft angle PNW, while the crankshaft angle KW is entered on the upper degree scale. The angular offset of 39 ° between the crankshaft and the pump camshaft 3 results in the illustrated offset between the angular positions of the pump camshaft and the crankshaft. In accordance with the previous explanations, this results in unfavorable engine cranking angles at a crank angle of 51 ° ± 5 °, 141 ° ± 5 °, 231 ° ± 5 °, 321 ° ± 5 °, 411 ° ± 5 °, 501 ° ± 5 ° and 681 ° ± 5 ° (KW).

The high-pressure pump 1 shown in FIG. 3 is designed as a two-piston pump and accordingly has two roller tappets 5 and two pump plungers 7, which interact with the pump camshaft 3. The pump camshaft 3 also has two opposed cams 4 in this embodiment. This high-pressure pump 1 is designed for mounting on a six-cylinder V-type internal combustion engine and the pump camshaft 3 is driven with a transmission ratio i = 3/4 of the crankshaft of the internal combustion engine. 2 revolutions of the crankshaft thus correspond to 1, 5 revolutions of the pump camshaft. The angular offset of the pump camshaft relative to the crankshaft is 16.36 °, whereby the pump always delivers, based on the pump camshaft angle, by this amount after the internal combustion engine cylinder TDC and therefore always at 16.36 ° in the engine cylinder TDC the engine cylinder TDC is. For the internal combustion engine, there are thus disadvantageous parking positions relative to the crankshaft, which are shown or reproduced in FIG. 4. The lower degree scale shows the pump camshaft angle PNW as in FIG. 2, while the crankshaft angle KW is entered on the upper degree scale. Due to the angular offset of 16.36 ° between the crankshaft and the pump camshaft 3, the illustrated offset between the angular positions of the pump camshaft and the crankshaft results. Corresponding to the previous explanations unfavorable setting off angles of the crankshaft result at 21, 7 ° ± 7 °, 141, 7 ° ± 7 °, 261, 7 ° ± 7 °, 381, 7 ° ± 7 °, 501, 7 ° ± 7 ° and 621, 7 ° ± 7 ° (KW). Relative to the pump camshaft 3, the tolerance band is also identical to the high-pressure pump 1 shown in FIG. 1, but since there is a transmission ratio of i = 3/4 from the crankshaft to the pump camshaft 3, the tolerance band increases approximately here

Claims

claims

A method of controlling an internal combustion engine having at least one piston pivotably attached to a crankshaft, and comprising a common rail injection system comprising a high pressure pump having a pump camshaft (3) having at least one cam (4) and at least one pump camshaft (3) ) via a roller tappet (5) cooperating pump plunger (7),

characterized in that the angular offset of the pump camshaft (3) is designed to the crankshaft with respect to a wear-minimized and operationally optimized operation of the internal combustion engine.

2. The method according to claim 1,

characterized in that the angular offset is optimized with regard to the operation of the injection system.

3. The method according to any one of the preceding claims,

characterized in that the angular offset with respect to the mechanical load of the injection system is optimized.

4. Method according to one of the preceding claims,

characterized in that at a fixed angular offset of the start and / or stop of the internal combustion engine takes place at a crankshaft angle, which is optimized for the operation of the injection system.

5. The method according to claim 4,

characterized in that the start and / or stop takes place at a crankshaft angle at which the at least one cam (4) of the pump camshaft (3) is in the range outside an upper or lower dead center of the roller tappet (5).

6. The method according to claim 5,

characterized in that an internal combustion engine electronics stops at a stop command, the crankshaft at a predetermined crankshaft angle.

7. The method according to claim 5 or 6,

characterized in that the internal combustion engine electronics by means of an auxiliary device at a stop command and / or start command further rotates the crankshaft to a predetermined crankshaft angle.