KR20170072803A - Method for restarting a multi-cylindrical internal combustion engine with intake manifold injection without torque supplied externally - Google Patents

Abstract

The present invention relates to a method for restarting a multicylinder internal combustion engine (2) in which a suction pipe injection (16) is carried out without external supply torque, wherein the rotation of the crankshaft (4) of the internal combustion engine (2) Is initiated by the ignition of the ignitable mixture in the first cylinder (3) in the expansion phase, while in the second cylinder (3) in the compression phase when the re-start is started, Is opened until the intake valve 5 of the cylinder 3 reaches a predetermined reduced final angle and then the ignitable mixture remaining in the second cylinder 3 is ignited to continue the rotation, Lt; RTI ID = 0.0 > of < / RTI >

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a multi-cylinder internal combustion engine,

The present invention relates to a method according to independent claim 1 for restarting a multi-cylinder internal combustion engine in which a suction pipe injection is performed without an external supply torque. Still another object of the present invention is an electronic control device, a computer program, and a machine-readable storage medium.

DE 10 2013 220 637 A1 describes a method for restarting a multi-cylinder internal combustion engine in which a suction pipe injection is performed without external supply torque, i.e. a method for performing an engine start without a starter. According to the known method, in the stopped state of the internal combustion engine, the rotation of the crankshaft of the internal combustion engine is started by direct injection of the fuel quantity into the cylinder of the internal combustion engine in the expansion phase and ignition of the ignitable mixture, And is continued by fuel injection into another cylinder of the internal combustion engine. By direct injection, fuel injection can be performed irrespective of whether the intake valves of the individual cylinders provided for fresh air supply are open or closed. On the contrary, in the internal combustion engine in which the suction pipe injection is performed without direct injection, the fuel amount per cylinder is injected into the intake pipe, and the generated fuel air mixture reaches the combustion chamber of the cylinder through the opened intake valve of the individual cylinder. It is more complicated to restart the engine in a stationary state without a starter in the case of an internal combustion engine provided only with a suction pipe injection, because the ignitable mixture feed to the individual cylinders can only be performed by the open intake valves of the cylinder.

In this context, a method and an electronic control device having the features of the independent patent claims are proposed. Other embodiments are disclosed in the dependent patent claims and the detailed description.

The proposed method provides re-operation of a multi-cylinder internal combustion engine using intake pipe injection of fuel without torque externally supplied, for example, by a starter, in which rotation of the crankshaft of the internal combustion engine is initiated when re- Initiated by ignition of the ignitable mixture in the first cylinder in the expansion phase; In the second cylinder, which is in the compression phase when the re-start is started and is preferably to be ignited next for continued rotation, the intake valve of the closed second cylinder before the start of re- , So that depressurization of the ignitable mixture into the suction pipe is effected; Followed by ignition of the ignitable mixture remaining in the second cylinder for continued rotation. In other words, the mixture in the first cylinder is first ignited, and subsequently, as the second ignition, the mixture in the second cylinder, which is not the same as the first cylinder, is ignited.

Numbering the cylinders as first, second, third or fourth cylinders by selecting to come before and after evenly in accordance with the planned ignition sequence at engine restarting indicates that the cylinders are adjacent to each other, For example, the first cylinder and the second cylinder are directly arranged, or the piston rods of these cylinders are connected to the crankshaft at a position immediately adjacent to each other for force transmission. The disclosed method is particularly aimed at a viscous four-stroke internal combustion engine in which each cylinder performs a sequence of inhalation phases, a compression phase, an expansion phase where the mixture is normally ignited, and a discharge phase In this case, in the suction phase and the expansion phase, the piston of the cylinder moves in the direction of bottom dead center from the cylinder top dead center, and in the compression phase and the discharge phase, the piston of the cylinder moves in the direction of top dead center point. In this case, it is assumed that at the start of the restart, the crankshaft is in a stop position that was taken as a result of engine costing leading to an engine stop state to be ended, and which was maintained during the engine stop state until restarting is started.

The term " reduced pressure " applied only during the compression phase of the cylinder in the adjacent cylinder means that the pressure in the combustion chamber of the adjacent cylinder, which is present in the combustion chamber of the adjacent cylinder before the intake valve is closed and thus the combustion chamber is shut off, Means that a portion of the air or fuel-air mixture is pushed back through the open intake valve of the cylinder into the intake pipe assigned to the cylinder during the compression phase. It is preferable that the outlet side of the combustion chamber is kept closed by the closing of the exhaust valve of the cylinder during the compression phase. The terms intake valve and exhaust valve are also understood as a plurality of intake valves or exhaust valves provided per cylinder. When a plurality of intake valves or exhaust valves are provided, the term " opened intake valve " or " exhaust valve " means that at least one of the intake valves or exhaust valves is open, and the term & Means that all of the intake valves or exhaust valves of the engine are closed.

No back pressure against the movement of the cylinder piston in the direction of top dead center from the bottom dead center is formed in the combustion chamber of the cylinder as long as the reduced pressure is achieved, in other words, the combustion chamber is not blocked during the compression phase. When the back pressure is formed, the rotation of the crankshaft connected to the piston, initiated by the first ignition, will be strongly braked. During depressurization, a portion of the fuel-air mixture in the combustion chamber of the cylinder is pushed back through the open intake valve into the suction tube by piston motion while another portion of the ignitable fuel-air mixture remains in the combustion chamber. As the intake valve is closed at the preset reduced pressure final angle, the mixture remaining in the combustion chamber continues to be compressed and ignited at a predetermined ignition timing, for example, when the piston of the cylinder passes the top dead center. In order to prevent the ignitable mixture in its first and second cylinders from becoming lean during the restart of the internal combustion engine, it is preferable that the intake valves and the exhaust valves of the cylinders be kept closed in the engine stop state.

The proposed method enables a robust and reliable re-start of the internal combustion engine in which the suction pipe injection is performed without the aid of a starter.

In an improvement of the method, in order to prepare for re-start, the engine is predicted to predetermine which cylinder will stop at its compression phase in an impending engine stop state, The amount of fuel sufficient to cause an ignitable mixture to be present in the cylinder at the time of restarting from the engine stop state, through the opened intake valve of the cylinder, in the intake step, which is executed last in the engine course, And is injected into the cylinder.

Further, in an improvement of the method of the present invention, in preparation for restarting, in the case of an engine running which induces an engine stop state to be ended, it is possible to predict which cylinder will stop at its own expansion phase in an imminent engine stop state, The amount of fuel enough to cause an ignitable mixture to be present in the cylinder at the time of restarting is supplied to the inside of the cylinder through the opened intake valve of the cylinder at the time of engine co- And the fuel quantity is homogenized with the ignitable mixture during the compression phase of the cylinder, preferably immediately following the inhalation phase in the engine costing state. At the end of the compression phase, at the transition to the expansion phase of the cylinder, i. E. To the rest position in the engine stop state, the homogenized ignitable mixture goes beyond the top dead center of the cylinder in the ignited state. Thereby, in the engine stop state, there is an ignitable homogeneous mixture, preferably a lambda-1 mixture, inside the cylinder which is to be stopped in its expansion phase. Through various measurements, the ignition power of the mixture that is ignited first during the restart of the engine to induce rotation of the crankshaft is much longer than what is required for a typical engine stop phase in a start / stop system 15 minutes). Thereby, a highly reliable re-start can be ensured even during the long engine stoppage state of the internal combustion engine in which the suction pipe injection is performed.

In addition, in an improvement of the method, in order to prepare for restarting with the end of engine costing leading to an engine stop state to be ended, the intake valves and the exhaust valves of the first and second cylinders are kept closed , And / or there is a lambda-1 mixture as ignitable mixture in the first and / or second cylinder during re-start. Thereby, during the engine stop state, in the first and second cylinders, the ignitable mixture becomes lean until it becomes a state where it is impossible to ignite, thereby improving the reliability of engine restart.

In one improvement of the method, the intake valve of the second cylinder is first kept closed during the predetermined crank angle range when the compression phase is started. This improvement example is based on the perception that backpressure is not present at the beginning of the compression phase, or that the backpressure is low enough so that rotation of the crankshaft initiated by the first ignition is initially unobstructed or only slightly disturbed.

In addition, in an improvement of the method, the third cylinder in the intake stage at the start of re-start, along with the start of the initial rotation of the crankshaft, releases the amount of fuel to form the ignitable mixture from the intake pipe, The intake valve of the third cylinder for effecting the depressurization is preferably moved from the bottom dead center to the bottom dead center in order to cause the depressurization in the subsequent compression phase as the second compression phase, Until it reaches a predetermined final reduced pressure angle, preferably associated with the crank angle, for the second compression phase. The reduced final angle preset by the second compression phase for the third cylinder is preferably equal to or greater than the previously defined reduced final angle by the first compression phase for an earlier closure of the individual intake valve, Which is relatively shorter and causes less decompression.

In addition, in an improvement of the method, the first compression phase of the cylinder after re-starting represents the third compression phase of all cylinders executed after at least re-start, for a fourth cylinder in the discharge phase when re- At the compression phase of the cylinder, the intake valve is closed to a predetermined reduced final pressure angle, preferably associated with the crank angle, which corresponds to the pressure reducing end angle of the starter start scenario or engine idle control time. In the case of a four-cylinder engine, this corresponds to the closing of the fourth cylinder at 120 ° KW prior to, for example, the ZOT (top dead center).

In one improvement of the method of the present application, it is also possible, for the first three compression phases to be carried out after restart, that is, for the second, third and fourth cylinders, the individual intake valves are opened for the longest in the first compression phase 3 < / RTI > compressed phase, respectively, are pre-set. For a four-cylinder engine, the final decompression angle for the second, third and fourth cylinders is preferably 60 ° KW before ZOT, 90 ° KW before ZOT or 120 ° KW before ZOT, with a tolerance range of ± 10 ° KW, preferably +/- 5 DEG KW, and particularly preferably +/- 1 DEG KW.

In an improvement of the method of the present application, when measuring the amount of fuel per cylinder, the action of the depressurization previously carried out in the cylinder is taken into account. In this case, the amount of mixture used to remain in the suction tube after depressurization and to form the mixture during the next inhalation phase is then considered or balanced in determining the amount of fuel to be injected into the suction tube. Thereby, a very precise lambda-1 mixture can be provided in the combustion chamber.

In one improvement of the method, the camshaft adjuster assigned to the intake valve of the second cylinder is already moving ahead of the current crank angular position of the second cylinder just before the point to open the intake valve. In order to avoid the dilution of the ignitable mixture of the second cylinder during the engine stop state, the intake valve of the second cylinder is kept closed during the engine stop state by the camshaft regulator. However, for dynamic reasons, the camshaft adjuster can already move just before the intake valve is opened, for example when the position of the second cylinder is 90 ° K before ZOT, it can move to 100 ° KW before ZOT.

In an improvement of the method of the present application, the camshaft adjuster assigned to the intake valve of the second cylinder also moves in the direction of the preset reduced pressure final angle only when the internal combustion engine is restarted. Thereby, it can be ensured that the ignition mixture in the second cylinder is not lean due to the intake valve opened during the engine stop state.

In both of the abovementioned improvements, the camshaft adjuster must be able to operate even when the engine is not rotating, that is, when the engine speed is zero.

In an improvement of the method of the present application, the ignition of the first cylinder in the expansion phase at the time of restarting is also delayed until the intake valve of the second cylinder in the compression phase is opened. Thereby, in any case before the rotation of the crankshaft is started, it can be ensured that the camshaft regulator assigned to the intake valve of the second cylinder can open the intake valve of the second cylinder. This ensures that the desired decompression is carried out.

An electronic control device designed to perform the above-described method is also provided. The method may be implemented as software or hardware within the control device, or as a mixture of software and hardware.

In addition, there is also provided a computer program for executing the method on a computer, and a machine-readable storage medium having the computer program stored thereon.

To illustrate the method described above, an embodiment with reference to the exemplary drawings is now introduced.

1 is a schematic view of an engine system including an internal combustion engine in which a suction pipe is injected.
2 is a view showing a stop position or a starting position of the internal combustion engine piston which is advantageous for restarting the internal combustion engine by the proposed method.
3 is a diagram illustrating one embodiment of a proposed method that utilizes a flowchart in an example of a four-cylinder-four-stroke engine.
4 is a view showing an embodiment of the proposed method in which the camshaft adjuster assigned to the intake valve of the second cylinder moves in the direction of the predetermined reduced final angle only when the internal combustion engine is restarted.

Fig. 1 schematically shows an engine system 1 with an internal combustion engine 2 having four cylinders 3 in the illustrated embodiment. The cylinders 3 are operated in a four-stroke mode and are supplied with the fuel-air mixture through the intake pipe injection plant 16. [ The intake pipe injection system 16 is supplied with fresh air through an air supply system 14 in which the amount of fresh air supplied is regulated through a throttle valve 12 incorporated in the air supply system 14. The intake pipe injection system 16 is connected to an air supply system 14 in the form of four intake pipes 11 for supplying fresh air to each cylinder and is connected to an intake valve 12 can inject fuel into the suction pipe. The internal combustion engine 2 is an internal combustion engine that does not self-ignite, and can be specifically formed as an auto engine.

In the conventional system, the cylinders 3 each have a piston connected to the crankshaft 4, respectively. The crankshaft 4 is connected to a drive train of the internal combustion engine 2 (not shown in the figure), for example, to provide engine torque for driving the automobile. Each cylinder 3 is provided with an intake valve 5 for supplying a fresh air or fuel-air mixture and an exhaust valve 6 for exhausting combustion exhaust gas. The opening timing and the closing timing of the intake valve 5 in the cylinders 3 are synchronized with the movement of the crankshaft 4 through the intake valve camshaft 7. [ In the same manner, the exhaust valve 6 in the cylinders 3 is also synchronized with the movement of the crankshaft 4 via the exhaust valve camshaft 8.

The intake valve camshaft 7 and the exhaust valve camshaft 8 are mechanically connected to the crankshaft 4. An intake valve camshaft adjuster 9 is provided which is capable of changing the opening and closing timing of the intake valves 5 of the cylinders 3 in relation to the crankshaft angle, i.e., the position of the crankshaft 4. [ In particular, by the intake valve camshaft adjuster 9, the phase position of the opening time interval of the associated intake valve 5 for the cylinder 3 in relation to the crankshaft angle can be determined.

Similarly, an exhaust valve camshaft adjuster 10 is provided that is capable of determining the opening and closing times of the exhaust valve 6 in the cylinders 3 in relation to the crankshaft angle of the crankshaft 4.

1 also shows an electronic control device 25 which is configured to execute the proposed method.

Fig. 2 shows that the stop position or the starting position of the pistons of the first cylinder 3 in the expansion phase at the start of restart and the piston of the second cylinder 3 in the compression phase at the start of restarting, . According to the proposed method, in order to realize starter-free engine start, it is preferable that one of the cylinders 3 is located at a specific stop position in the expansion phase or stopped at a specific stop position when the engine is running. The expansion phase E is the phase of the crankshaft 4 in which the piston is in the combustion stroke position during operation of the internal combustion engine 2, that is, between the top dead center (minimum combustion chamber volume) and bottom dead center (maximum combustion chamber volume) ≪ / RTI > The stop position determines what kinetic energy can be provided by the first combustion in the associated cylinder 3 to implement engine casting. It is also possible to perform the compression of the piston of another cylinder 3 in which the provided kinetic energy is in the compressed phase K, i.e. between the bottom dead center ZUT and the top dead center ZOT, Lt; RTI ID = 0.0 > (ZOT). ≪ / RTI > 2 shows an example of the piston of the first cylinder in the expansion phase E at the start of restart and the piston with the rod 21 and of the second cylinder in the compression phase K at the start of re- The 90 DEG KW after the ZOT is shown, which is very suitable for the starter-free start of the four-cylinder internal combustion engine. The individual pistons and rods of the two cylinders are shown symbolically in the overlapping view in Fig. Also shown in Figure 2 is a pre-set vacuum final angle associated with the crank angle, indicated at 23, from which the intake valves of the second cylinder (with the piston and rod 22) are closed.

In Fig. 3, an embodiment of the proposed method is shown using a flowchart for starterless start of the four-cylinder-four-stroke engine 2 shown in Fig. When the re-start of the internal combustion engine 2, which is not the self-ignition type, is started, the crankshaft 4 is stopped at step S0 and the first cylinder 3 in the expansion phase and the second cylinder 3 in the compression phase The intake valves 5 and the exhaust valves 6 are closed. The internal combustion engine 2 is at 90 ° KW after the ZOT. In step SO, an ignitable fuel-air mixture, preferably a lambda-1 mixture, is introduced into the combustion chamber of the first cylinder 3 and the combustion chamber of the second cylinder 3, respectively. Then, in step S1 in which the rotation of the crankshaft 4 is started, the ignitable mixture in the first cylinder 3 is ignited, and the intake valve 5 of the second cylinder 3 is opened. While the crankshaft 4 rotates and through which the four pistons of the internal combustion engine 2 are displaced into the moving state, in the step S2, the second cylinder 3 is pre-set to a predetermined reduced final angle < RTI ID = Has already been reached. If not reached (S2N), step S2 is executed again. In the meantime, the piston of the second cylinder 3 continues its movement from the bottom dead center to the top dead center, at which time the intake valve 5 of the second cylinder 3, which has been accommodated in the combustion chamber of the second cylinder A portion of the ignitable mixture is transferred into the suction pipe (11) of the second cylinder (3). On the other hand, if the second cylinder 3 has reached the predetermined reduction final angle (S2J) before 60 deg. K, the intake valve 5 of the second cylinder 3 is closed in step S3. Thereby, the decompression and the operation in which the ignitable mixture is moved from the combustion chamber of the second cylinder 3 through the intake valve 5 of the cylinder into the suction pipe 11 are also ended. In step S4 following step S3, when the intake valve 4 of the second cylinder 3 is closed, the ignitable mixture contained in the combustion chamber of the cylinder is compressed do. Then, in step S5, the ignitable mixture which has been received and compressed in the second cylinder is ignited in the ZOT so that the piston of the second cylinder is pressed in the direction of bottom dead point from the top dead center, ). ≪ / RTI > Step S6 symbolically shows the end of the basic concept of the proposed method.

4 shows an embodiment of the proposed method in which the camshaft adjuster assigned to the intake valve of the second cylinder moves in the direction of the predetermined reduced final angle only when the internal combustion engine is restarted. 4, the curve 40 represents the behavior of the crank angle with respect to time t, and the curve 41 represents the open or closed state of the intake valve 5 of the second cylinder. Within the time interval A, the intake valve 5 is closed until reaching 90 ° KW before the ZOT. Within the time interval B before the ZOT and before the time interval B of 60 KW before the ZOT, i.e., within the predetermined reduced final angle for the second cylinder of the four-cylinder engine, the intake valve 5 of the second cylinder is open , So that the depressurization of the mixture present in the combustion chamber into the suction line can be achieved. From the crank angle before the ZOT 60 KW or less, the intake valve 5 is closed until the ZOT is reached, as reproduced by the interval C in Fig.

Claims (15)

A method for restarting a multi-cylinder internal combustion engine (2) in which a suction pipe injection (16) is performed without an external supply torque,
The rotation of the crankshaft 4 of the internal combustion engine 2 is initiated by the ignition S1 of the ignitable mixture which takes place in the first cylinder 3 in the expansion phase E when re- In the second cylinder 3 in the compression phase K at the start of the re-start, the intake valve 5 of the second cylinder 3 which has been closed before the start of the re-start reaches a predetermined reduced final angle 23 (S1, S2) of the ignitable mixture into the intake tube (11), followed by the ignition of the ignitable mixture (S1, S2) remaining in the second cylinder (3) Of the internal combustion engine. 2. The method according to claim 1, further comprising the steps of: predicting which cylinder (3) will stop at its compression phase (K) in an impending engine stop state, (3) is injected into the cylinder (3) at the time of engine casting, so that a quantity of fuel is injected such that the ignitable mixture is present in the cylinder (3) when the engine is restarted A method of restarting a cylinder internal combustion engine. 3. The method according to claim 1 or 2, wherein, in preparation for re-starting, the engine (3) induces an engine stop state to be terminated, in which the cylinder (3) stops at its own expansion phase And a quantity of fuel is injected into the cylinder (3) at the intake stage of the cylinder (3) at the time of engine casting to such an extent that the ignitable mixture exists in the cylinder (3) Characterized in that the fuel quantity is homogenized with the ignitable mixture during the compression phase (K) of the cylinder following the intake phase. 3. A method according to claim 1 or 2, wherein the intake valves (5) of the first and second cylinders (3) are operated until restarted, in order to prepare for restarting with the end of engine costing, Characterized in that the first and / or the second cylinder (3) is maintained in a continuously closed state and / or the lambda-1 mixture is present as an ignitable mixture in the first and / or second cylinder (3) . 3. A method according to claim 1 or 2, characterized in that at the beginning of the compression phase (K) the intake valve (5) of the second cylinder (3) is first kept closed during the predetermined crank angle range Of the internal combustion engine. 3. A method as claimed in claim 1 or 2, characterized in that the third cylinder (3) in the intake stage at the start of the re-start receives the amount of fuel for forming the ignitable mixture, with the start of the initial rotation of the crankshaft, In the subsequent compression phase K as the second compression phase K, the intake valve 5 of the third cylinder for causing the depressurization is connected to the predetermined decompression end angle 23 for the second compression phase And the valve is opened until the exhaust gas reaches the exhaust passage. 3. A method according to claim 1 or 2, characterized in that the first compression phase (K) of the cylinder (3) after re-starting for the fourth cylinder (3) in the discharge phase at the start of re- Wherein the intake valve (5) of the cylinder (3) is closed to a predetermined reduced final angle (23) at a compression phase (K) of the cylinder (3) Gt; wherein < / RTI > corresponds to a final decompression angle of the starter start scenario. 3. The method according to claim 1 or 2, characterized in that, for the first three compression phases (K) executed after restart, the individual intake valves (5) are opened for the longest time in the first compression phase (K) K are preset to be the shortest open in the first and second cylinders (K, K), respectively. 3. The method for restarting a multicylinder internal combustion engine according to claim 1 or 2, wherein, when measuring the amount of fuel per cylinder, the action of the depressurization previously performed in the cylinder is taken into account. 3. The intake valve according to claim 1 or 2, wherein the camshaft adjuster (9) assigned to the intake valve (5) of the second cylinder (3) Is moved ahead of the current crank angular position (40) of the cylinder (3). 3. The internal combustion engine as set forth in claim 1 or 2, characterized in that the camshaft adjuster (9) assigned to the intake valve (5) of the second cylinder is moved in the direction of the predetermined reduction end angle (23) Of the internal combustion engine. 3. The method according to claim 1 or 2, wherein the ignition of the first cylinder (3) in the inflation phase during re-operation is continued until the intake valve (5) of the second cylinder (3) Wherein the engine is delayed when the engine is stopped. An electronic control device (25) designed to carry out the method of one of the methods according to claims 1 or 2. A computer program comprising instructions executable by a computer to perform the method according to any one of claims 1 to 3 when executed on a control device and stored in a machine-readable storage medium. 15. A machine-readable storage medium having stored thereon a computer program according to claim 14.

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