JP2013083185A - Internal combustion engine, and control method of piston stop position thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal combustion engine mounted on an automobile employing an idle reduction (idling stop) system that is allowed to be started at the first compression stroke upon a restart after a temporarily stop of the internal combustion engine, thereby enabling an engine start time to be reduced and a commercial value as a vehicle to be improved, and to provide a control method of a piston stop position of the internal combustion engine.SOLUTION: The internal combustion engine includes a control device 20 that introduces compressed air from external devices 15 and 18 to a cylinder 11c in the intake stroke immediately before an operation stop of the internal combustion engines 10 and 10A at a timing Tin which is set or calculated in advance to cause a piston to stay in the vicinity of the bottom dead center in the compression stroke which is next stroke following the intake stroke.

Description

  The present invention relates to an internal combustion engine mounted on a vehicle that employs an idle reduction (idling stop) system, and an internal combustion engine capable of shortening an engine start time after temporarily stopping the internal combustion engine and starting the engine early. The present invention relates to an engine piston stop position control method.

  In general, an internal combustion engine (engine) determines cylinders (cylinders) using a cam rotation sensor, a crank rotation sensor, etc., determines the timing of starting fuel injection into each cylinder, and starts the internal combustion engine using a starter or the like. When the fuel injection time comes, fuel is injected into the cylinder and the operation of the internal combustion engine is started.

  However, the stop position of the piston when the operation of the internal combustion engine is stopped is not necessarily a specific position and is unstable. For this reason, when a general engine start control logic is used, when the internal combustion engine is restarted, the fuel injection start instruction immediately after the engine starts rotating is not constant, so the start time varies. There's a problem. It is desirable not only that the starting time is constant, but also it is desirable to shorten the time taken for starting itself.

  FIG. 4 shows the engine speed, the in-cylinder pressure of each cylinder (cylinder pressure), and the rotation direction of the crankshaft related to the behavior of the piston when the internal combustion engine stops operating. Further, as shown in FIG. 5, when the engine is stopped, a force in the reverse rotation direction is applied by the cylinder internal pressure of the cylinder in the compression stroke immediately before the rotation of the crankshaft is stopped, or the cylinder of the cylinder in the opposite expansion stroke It has been experimentally known that the rotation stops when the stop position of the piston is around 80 degrees (deg) before the top dead center of the compression stroke of the cylinder while repeating the forward rotation and the reverse rotation by pushing against the internal pressure.

  When the operation of the internal combustion engine is started from the piston stopped state, the cylinder is compressed first. The first compression (first time) by the compression operation from about 80 degrees before the top dead center. In the compression stroke), a temperature and pressure field sufficient for ignition cannot be formed.

  Therefore, in the existing engine start control logic, the first explosion is carried over to the third compression, and depending on the stop position of the piston, it is carried over to the fourth compression. As a result, the time required for starting becomes longer.

  The problem of longer start-up time at the start of engine operation has a negative impact on product performance in vehicles equipped with an idle reduction system that frequently repeats engine stop and engine start. The solution to this problem has become a very important issue.

  In this connection, for example, at the start of idling stop control, the air conditioner and alternator are stopped, the ignition timing is set with the retard amount of the spark plug according to the magnitude of the engine load, and then the engine speed When the engine pressure drops to the specified value, the engine is stopped and the engine is stopped. The engine is stopped and the engine is stopped and the engine is stopped and the fuel is cut. An apparatus has been proposed (see, for example, Patent Document 1).

  In this internal combustion engine automatic stop device, the engine output energy is also a constant value when the engine load is a certain value and the engine speed is a certain value. The piston always stops at a certain fixed position.

  For example, when the crank angle is controlled to stop at the optimum crank angle stop position, or when the crank angle stop position can be estimated with high accuracy, the engine is automatically restarted by an electric motor or a motor generator at the time of restart. If this is not the case, a stop / start control device for an internal combustion engine has been proposed that restarts the engine quickly and reliably with a DC starter having a larger output torque than the motor generator (see, for example, Patent Document 2).

JP 2007-231786 A JP 2004-239111 A

  The present invention has been made in view of the above situation, and an object of the present invention is to restart the engine after it is temporarily stopped in an internal combustion engine that is mounted on an automobile that employs an idle reduction system. In this case, the engine can be started in the first compression stroke, whereby the engine start time can be shortened and the commercial value of the vehicle can be improved, and the piston stop position control of the internal combustion engine It is to provide a method.

  In order to achieve the above object, an internal combustion engine of the present invention introduces compressed air from an external device into a cylinder in an intake stroke immediately before the operation of the internal combustion engine is stopped at a timing set or calculated in advance. Is provided with a control device that keeps the vicinity of the bottom dead center of the compression stroke, which is the next stroke of the intake stroke.

  In other words, the compressed air is instantaneously pushed into the cylinder in the intake stroke immediately before the stop of the internal combustion engine at a preset or calculated timing from an external device, and the piston is forced to be near the bottom dead center of the compression stroke which is the next stroke. By stopping, the control is performed to stop the piston at a position where the next internal combustion engine can be quickly started. That is, the stop position of the piston is controlled using compressed air from an external device.

  According to this configuration, the piston stop position in one cylinder at the completion of the stop of the rotation of the internal combustion engine can be made near the bottom dead center of the compression stroke. The cylinder whose stop position is near the bottom dead center of the compression stroke can be specified as the cylinder to be compressed first, and one compression start by the first explosion from the first compression becomes possible. As a result, the engine can be started quickly and the engine start time can be shortened. Note that cylinder discrimination as to whether or not the cylinder is in the intake stroke can be made using detection values of the cam rotation sensor and the crank rotation sensor.

  In the internal combustion engine, the control device predicts the engine rotational speed immediately before the stop from the engine rotational speed at the time when the operation stop command for the internal combustion engine is received, and immediately before the engine rotational speed decreases to the target rotational speed. If the control for introducing the compressed air is performed, the timing set in advance or calculated can be determined with relatively simple control, and the piston stop position in one cylinder at the completion of the operation stop of the internal combustion engine is determined as the compression stroke. Near the bottom dead center.

  In the internal combustion engine described above, compressed air is supplied from a pressure accumulating tank connected to an intake manifold, and the control device controls the intake air just before the stop by opening / closing control of an on-off valve disposed at the outlet of the pressure accumulating tank. If the configuration is such that the introduction of the compressed air into the cylinder in the stroke is controlled, the compressed air can be sent to the cylinder by a very simple valve opening / closing control.

  In the internal combustion engine, an electric compressor is driven by an electric motor driver to supply compressed air to an intake manifold, and the control device controls the electric motor driver to a cylinder in an intake stroke immediately before stopping. If the configuration is such that the introduction of compressed air is controlled, the compressed air can be sent to the cylinder by simple motor driver control.

  In order to achieve the above object, a piston stop position control method for an internal combustion engine according to the present invention is the piston stop position control method for an internal combustion engine, in which compressed air is supplied in advance from an external device to a cylinder in an intake stroke immediately before the stop. It is a method characterized in that it is introduced at a set or calculated timing and the piston is kept near the bottom dead center of the compression stroke, which is the next stroke of the intake stroke.

  According to this method, since the piston stop position in one cylinder at the completion of the stop of the operation of the internal combustion engine can be made near the bottom dead center of the compression stroke, the piston stop is performed when the operation of the internal combustion engine is restarted. The cylinder whose position is in the vicinity of the bottom dead center of the compression stroke can be specified as the cylinder to be compressed first, and one compression start by the first explosion from the first compression can be performed. As a result, the engine can be started quickly and the engine start time can be shortened.

  According to an internal combustion engine and a piston stop position control method for an internal combustion engine according to the present invention, in an internal combustion engine that is mounted on an automobile that employs an idle reduction system, restarting after temporarily stopping the internal combustion engine is performed. In this case, the engine can be started in the first compression stroke, thereby shortening the engine starting time. Therefore, it is possible to improve the product performance in a vehicle equipped with an idle reduction system that repeatedly stops and starts the engine.

It is a figure which shows the structure of the internal combustion engine of the 1st Embodiment of this invention. It is a figure which shows the structure of the internal combustion engine of the 2nd Embodiment of this invention. It is a figure which shows an example of the timing of supply in the cylinder of the compressed air of embodiment of this invention. It is a figure which shows an example of the time series of the engine speed at the time of a stop of the internal combustion engine in a prior art, cylinder pressure, and the rotation direction of a crankshaft. It is a figure which shows the position of the piston at the time of the stop of the internal combustion engine in a prior art.

  Hereinafter, an internal combustion engine according to an embodiment of the present invention and a piston stop position control method for the internal combustion engine will be described with reference to the drawings.

  As shown in FIG. 1, an internal combustion engine (engine) 10 according to the first embodiment includes an intake manifold 11a, an exhaust manifold 11b, a cylinder (cylinder) 11c, an injector (fuel injection device) 11d, etc. Is arranged. An intake passage 12 is connected to the intake manifold 11a, and an exhaust passage 13 is connected to the exhaust manifold 11b. A compressor 14 a of a turbocharger 14 is provided in the intake passage 12 for taking in air A, and a turbine 14 b of the turbocharger 14 is provided in the exhaust passage 13 from which exhaust gas G is discharged.

  The internal combustion engine 10 according to the first embodiment further includes a pressure accumulation tank 15 that stores the compressed air Ac, a compressed air supply passage 16 that connects the pressure accumulation tank 15 and the intake passage 12, and the compressed air. When the on-off valve 17 is provided in the supply passage 16 and the on-off valve 17 is opened, the compressed air Ac from the pressure accumulation tank 15 passes through the compressed air supply passage 16, the intake passage 12, and the intake manifold 11a to enter the cylinder 11c. It is configured so that it can be introduced.

  Further, a control device 20 called an ECU (engine control unit) for controlling the overall operation of the internal combustion engine 10 is provided, and the on-off valve 17 is also controlled. That is, the control device 20 receives detection signals from a cam rotation sensor (not shown), a crank rotation sensor (not shown), etc., and outputs an injector drive signal, a compressed air control signal, and the like.

  Next, a method for controlling the piston stop position of the internal combustion engine in the internal combustion engine 10 will be described. This control is performed by the control device 20. This control is related to a flow of a series of operations from engine stop to start. First, an engine stop command is issued such that the idle reduction system detects a temporary stop of the internal combustion engine and stops the operation of the internal combustion engine 10. Specifically, when a fuel cut command is received in the control device 10, the engine speed (target) immediately before the engine is stopped is predicted from the engine speed at the time when the engine stop command is received. Control is performed to introduce the compressed air Ac immediately before the actual engine speed decreases to the predicted target engine speed. When this compressed air Ac is introduced, the operation of the on-off valve 17 and the time that elapses while the compressed air Ac passes through the compressed air supply passage 16, the intake passage 12, and the intake manifold 11 a, that is, the response delay of the compressed air introduction is reduced. Considering this, the on-off valve 17 is operated slightly before. This timing is set in advance or calculated.

  By introducing this compressed air Ac, the piston stops near the bottom dead center where the force to push the piston upward and the gas pressure in the cylinder into which the compressed air Ac is introduced are balanced. On the other hand, the control device 20 determines and stores the cylinders in the compression stroke at the time of stopping. Whether or not the cylinder is in the compression stroke is determined using the detection values of the cam rotation sensor and the crank rotation sensor.

  When the engine is restarted to resume the operation of the internal combustion engine 10, the cylinder in the compression stroke at the time of stop is determined from the memory of the control device 20. This cylinder is compressed for the first time when the engine is started, and a sufficient temperature and pressure field are formed to ignite even when fuel is injected. I can ignite. In other words, the first explosion is possible from the first compression. As a result, the engine start time can be shortened.

  FIG. 3 shows the in-cylinder pressure of each cylinder, the introduction start timing (time point) Tin of the compressed air Ac, and the rotation stop (engine complete stop) of the internal combustion engine 10 when the piston stop position is controlled. Timing Ts is shown. In FIG. The cylinder No. 4 is the cylinder where the piston stops at the compression stroke and the first explosion occurs at the first compression at the next restart.

  Next, an internal combustion engine according to a second embodiment will be described. As shown in FIG. 2, the internal combustion engine 10A according to the second embodiment includes an electric turbo 18 and an electric compressor instead of the turbocharger 14, the compressor 14a, and the turbine 1b of the internal combustion engine 10 according to the first embodiment. 18a, a turbine 18b, and an electric driver 19 for driving and controlling the electric turbo 18, and a pressure accumulating tank 15 and a compressed air supply passage of the internal combustion engine 10 of the first embodiment. 16 is different in that the on-off valve 17 is not provided.

  In addition, this electric turbo is different from a device having a compressor without a turbine, such as an electric or mechanical supercharger (supercharger), and is an electric type in which the compressor of the turbocharger can be driven by an electric motor (motor). It is also a turbo-type turbocharger.

  In this internal combustion engine 10A, the operation of the compressor 18a of the electric turbo 18 driven and controlled by the electric driver 19 pressurizes the air A into compressed air Ac, and this compressed air Ac is made into the intake passage 12 and the intake manifold 11a. Via, it is comprised so that it may introduce in the cylinder 11c.

  The control of the piston stop position in the internal combustion engine 10A of the second embodiment is the same as the control of the piston stop position in the internal combustion engine 10 of the first embodiment, and the control of the supply of compressed air Ac is the first control. In the internal combustion engine 10 of the first embodiment, the opening / closing control of the on-off valve 17 is performed, whereas in the internal combustion engine 10A of the second embodiment, the electric turbo 18 is driven and controlled by the electric driver 19. This control is performed by the control device 20. That is, an electric motor operation command signal is output from the control device 20 instead of the compressed air control signal (open / close valve control signal).

  According to the internal combustion engine 10, 10A having the above-described configuration and the piston stop position control method for the internal combustion engine, compressed air is set in advance from the external devices 15, 18 to the cylinders in the intake stroke immediately before the stop of the internal combustion engine 10, 10A. The piston is stopped at a position where the next internal combustion engine can be started quickly by pushing in instantaneously at the calculated timing Tin and forcibly holding the piston near the bottom dead center of the compression stroke. . That is, the stop position of the piston is controlled using the compressed air Ac from the external devices 15 and 18.

  As a result, the piston stop position in one cylinder at the completion of the rotation stop of the internal combustion engine 10, 10A can be made near the bottom dead center of the compression stroke with relatively simple control. When restarting the operation of 10A, the cylinder whose piston stop position is in the vicinity of the bottom dead center of the compression stroke can be specified as the cylinder to be compressed first, and one compression start by the first explosion from the first compression Is possible. As a result, the engine can be started quickly and the engine start time can be shortened.

  According to the internal combustion engine and the piston stop position control method of the internal combustion engine of the present invention, in an internal combustion engine mounted on a vehicle that employs an idle reduction system, at the time of restart after temporarily stopping the internal combustion engine Since the engine can be started with one compression and the engine start time can be shortened, it can be used as an internal combustion engine for many vehicles and a piston stop position control method for the internal combustion engine.

10, 10A Internal combustion engine
11 Engine body 11a Intake manifold 11b Exhaust manifold 11c Cylinder
11d Fuel injector 12 Intake passage 13 Exhaust passage 14 Turbocharger (turbo supercharger)
14a Compressor 14b Turbine 15 Accumulated tank 16 Compressed air supply passage 17 On-off valve 18 Electric turbo 18a Compressor 18b Turbine 19 Motor driver 20 Braking device (ECU)
A Air Ac Compressed air G Exhaust gas

Claims (5)

  Compressed air is introduced from an external device into the cylinder in the intake stroke immediately before the operation of the internal combustion engine is stopped at a preset or calculated timing, and the piston is placed near the bottom dead center of the compression stroke, which is the next stroke of the intake stroke. An internal combustion engine comprising a control device for fastening. Control in which the control device predicts the engine speed just before the stop from the engine speed at the time when the operation stop command of the internal combustion engine is received, and introduces compressed air immediately before the engine speed decreases to the target speed The internal combustion engine according to claim 1, wherein:   Compressed air is supplied from a pressure accumulating tank connected to the intake manifold, and the control device controls the opening / closing valve disposed at the outlet of the pressure accumulating tank to open and close the cylinder in the intake stroke immediately before stopping. The internal combustion engine according to claim 1 or 2, wherein the introduction of compressed air is controlled.   The motor driver is configured to drive the electric compressor to supply compressed air to the intake manifold, and the control device controls the introduction of the compressed air to the cylinder in the intake stroke immediately before the stop by the control of the motor driver. The internal combustion engine according to claim 1 or 2, wherein:   In the piston stop position control method of an internal combustion engine, compressed air is introduced into a cylinder in an intake stroke immediately before stop at a timing set or calculated in advance from an external device, and the piston is subjected to a compression stroke that is the next stroke of the intake stroke. A piston stop position control method for an internal combustion engine, characterized in that the piston stop position is maintained near a bottom dead center.

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