DE102007009857A1 - Motor control unit for controlling automatic disconnecting operation of internal combustion engine, has direct injection, where motor control unit automatically disconnects combustion engine by corresponding disconnection measures - Google Patents

Abstract

The motor control unit has a direct injection, where the motor control unit automatically disconnects the internal combustion engine by corresponding disconnection measures, when all conditions of disconnection are fulfilled. The disconnecting measures are divided into preparatory disconnection measures and residual disconnection measures and the motor control unit carries out such preparatory disconnection measures by recognizing driver stop desire, that the suction pipe pressure (Ps) in the suction pipe is reduced.

Description

The The invention relates to a motor controller for controlling a automatic shutdown of an internal combustion engine with direct injection according to the preamble of claim 1.

Around To reduce fuel consumption and pollutant emissions currently processes and systems are developed and partly already used, which the internal combustion engine of a motor vehicle under certain conditions or in the presence of predetermined shutdown automatically switch off and automatically in the presence of predetermined connection conditions turn on again. Such methods and systems are above all else for city traffic to reduce fuel consumption Suitable because in city traffic the vehicle often at traffic lights or due the traffic comes to a halt and the operation of the internal combustion engine is not required.

So is out of the DE 101 61 343 A1 an automatic stop and start control device for an internal combustion engine is known, wherein the control device performs appropriate measures for switching off the internal combustion engine when all said shutdown conditions are met. For example, the speed of the vehicle must be below a predetermined threshold, an idle switch must be on, and a gearshift position of the transmission must be in neutral.

The Known methods and systems all have in common that the automatic Shutdown or the measures for automatic shutdown the internal combustion engine to be initiated only when all predetermined Shutdown conditions are met. Thus, it takes relatively long, until the internal combustion engine is switched off. In certain circumstances It can also happen that due to the prevailing in the intake manifold Pressure at the time of automatic shutdown of the internal combustion engine Vibrations occur and thus it is a short-term uneven running the internal combustion engine comes. This vibration mainly occurs enthrottled combustion process, for. B. in direct injection systems on. Both the long duration to the internal combustion engine final is switched off, as well as the possibly occurring "shaking" the internal combustion engine affect the driver with regard to the comfort of this automatic shutdown system negative.

task The invention is thus an engine control system for internal combustion engines specify with direct injection, in which the vibrations of the internal combustion engine during an automatic shutdown of the internal combustion engine prevented or at least reduced.

These Task is solved by a motor control according to claim 1. Advantageous developments emerge from the dependent Claims.

Of the Invention is based on the finding that the vibrations during automatic shutdown of the internal combustion engine by a too high Intake manifold pressure caused. Would a Redzierung the intake manifold pressure to be made only if all predetermined Shutdown conditions for initiating an automatic shutdown would be present, the time to shutdown the internal combustion engine by switching off the fuel injection or the ignition not sufficient to provide the necessary low intake manifold pressure to be able to. Would the engine control after the presence all shutdown conditions only a reduction of the intake manifold pressure and only when the necessary low intake manifold pressure is reached is to stop the injection and / or stop the ignition, It would take a long time for the internal combustion engine is completely switched off.

The Motor control according to the invention for control an automatic shutdown of an internal combustion engine with Direct injection is characterized by the fact that the shutdown measures in preparatory shutdown measures and remaining shutdown measures be divided and preparatory actions already be made prior to the presence of all shutdown conditions, namely, when the driver stop request is recognizable. The engine control takes on recognizing the driver stop request then such preparatory Abschaltmaßnahme before that present in a suction pipe Intake manifold pressure is reduced. The intake manifold pressure is reduced until, until a preset negative pressure in the intake manifold is established.

is The motor vehicle, for example, with a hybrid drive unit from an internal combustion engine and an electric motor for driving the Motor vehicle equipped, in certain situations, too the engine is switched off and the vehicle only with the Electric motor operated. A division into preparatory shutdown measures and remaining shutdown measures as they are the subject of Invention can also be in such a shutdown the internal combustion engine are made. The named driver stop request corresponds to an operational stop request of the hybrid system.

Advantageously, the intake manifold pressure is reduced by the fact that the engine control in such engages the operation of the internal combustion engine, that at the time of detecting the driver stop request in the stratified mode internal combustion engine is switched to the homogeneous mode and / or that a throttle in the intake manifold class is controlled such that the air flow decreases in the intake manifold.

at Internal combustion engine with direct injection is in a homogeneous operation the fuel during the intake stroke, and in a shift operation the fuel during the compression stroke into the combustion chamber the internal combustion engine injected. Homogenous operation is preferred intended for the full load operation of the internal combustion engine while the shift operation for idle and part load operation suitable is. In general, it can be assumed that the internal combustion engine when detecting the driver stop request in homogeneous operation located. However, under certain circumstances it can occur that the internal combustion engine when detecting the driver stop request in shifts. Will now when recognizing the driver stop request switched to the homogeneous operation, the reduced in the intake manifold present intake manifold pressure.

is If the internal combustion engine is already in homogeneous operation, the Intake manifold pressure thereby further reduces that the throttle changed in their position so that less air nachgeliefert in the suction pipe. Such a control of Throttle valve can also be used in combination with switching from shift operation be made in the homogeneous operation.

additionally can still further preparatory shutdown be initiated by the engine control. So can the engine control with recognized driver stop request additionally such carry out preparatory shutdown measures, that in the motor vehicle existing exhaust gas recirculation valve is closed and / or that an existing in the vehicle variable camshaft adjusting brought into its final position is and / or present in a fuel supply pipe Fuel pressure increased for later launch is, and / or that due to active ancillaries ancillaries load will reduce. By reducing the ancillary load is reduces the required torque. This allows the to be sucked Air quantity can be reduced.

Has the intake manifold pressure reaches a predetermined first vacuum threshold or undershot and / or was a predetermined first time interval from Time of recognition of the driver stop request exceeded and / or the internal combustion engine was at the time of recognition the driver stop request in homogeneous operation and has the relative filling in the suction system, so the air mass in the suction system a predetermined Filling limit reached or fallen below, sends the engine control in an advantageous embodiment of the invention an acknowledgment signal to show that from the side of the internal combustion engine an automatic shutdown nothing stands in the way. are all other shutdown conditions are met and is a driver's termination of the automatic shutdown not more possible, the engine management directs the remaining Abschaltmaßnahmen for automatically switching off the internal combustion engine one.

The remaining shutdowns may be in first remaining Shutdown measures and second remaining shutdown measures be split, which are initiated at a staggered time. advantageously, the engine controller takes such first remaining shutdown actions that an existing throttle class completely closed and / or that the ignition timing of an existing Ignition system is retarded and / or that a deactivated generator is reactivated. Through the whole Closing the throttle, the intake manifold pressure can now be lowered to an absolute minimum, reducing the vibrations can be additionally damped in the outlet and Z. B. a noise by a vibrating dual mass flywheel can be avoided. By the ignition angle adjustment late and the connection of the generator is less Combustion torque generated, causing the internal combustion engine faster is completely off.

If the driver stop request is recognizable or if a predetermined second Time interval after the initiation of the remaining shutdown measures has passed, the engine control can in an advantageous embodiment the invention during the phaseout of the internal combustion engine take start-up measures. This can a much faster start in the presence of all connection conditions be enabled. Partially, the startup can Measures also already be made when the driver stop request is recognized. Such a measure would be, for example. the increase of the fuel pressure. In principle, you can start-up measures within a time window be made at the time from the driver stop request is detected, starts, and at the time by the internal combustion engine is turned off, ends.

If the shutdown is a system-related shutdown of the internal combustion engine in a motor vehicle with a hybrid drive unit, can by means of electric drive Ver internal combustion engine are stored in an optimal start position.

advantageously, For example, the engine control system may undertake such a start-up procedure Make that a closed throttle open becomes. This suddenly increases the intake manifold pressure, so that when automatically turning on the engine again ambient pressure prevails in the intake manifold. Corresponds to the pressure in the suction pipe again in about a predetermined third pressure threshold, which is identical to the ambient pressure, the throttle can be closed again. As another start-up measure For example, the fuel pressure in a fuel delivery pipe can be increased become.

If during the time from the initiation of the remaining shutdown measures until initiation of the start preparations measures start request conditions or all connection conditions, the motor control must ensure that the throttle opens again, thus the necessary intake manifold pressure for the automatic Power-on can be provided.

The inventive method will now be based on a Embodiment explained in more detail. there the only figure shows a plotted over time Intake manifold pressure before and after an automatic Switching off a gasoline engine with direct injection, taking into account the Motor control according to the invention.

The FIG. 1 shows an intake manifold pressure plotted over time t Ps within a pig's ear, through which the necessary for combustion Air is sucked into the respective cylinder. Pu is the ambient pressure marked outside with the gasoline engine Direct injection equipped motor vehicle prevails.

from The beginning of the time representation t0 is up to the time t1 the internal combustion engine due to current operating parameters in shift operation, d. H. the fuel gets during the compression stroke injected into the combustion chamber of the internal combustion engine. In the intake manifold There is a pressure of Ps1, which is slightly lower than that Ambient pressure Pu. At time t1 receives the engine control unit due to an input signal, the information that the driver a shutdown of the internal combustion engine wishes. thereupon the motor control switches from shift operation to homogeneous operation the internal combustion engine, which closes the exhaust gas recirculation valve, the part of an exhaust gas recirculation system for controlling and / or rules of exhaust gas recirculation is and throttles by controlling the throttle valve the air flow. By the Change of the operating mode of the internal combustion engine, the closing of the Exhaust gas recirculation valve and throttling decreases the pressure Ps in the suction pipe of Ps1 at time t1 to a second Intake manifold pressure Ps2 at time t2. Within the period of t1 and t2 are additionally initiated measures d_K, the to an increase in the fuel pressure in the fuel supply pipe to lead.

in the At time t2, the intake manifold pressure Ps has a predetermined first negative pressure threshold Ps2 reached. Then an acknowledgment signal is generated. From this Time t2 is also a driver-side cancellation of the automatic Switch-off process no longer possible. Furthermore lie all other shutdown conditions. From this time t2 closes the engine control system completely covers the throttle valve in the intake manifold, so that the intake manifold pressure Ps is further reduced. In addition will the injection switched off and an ignition retard made, creating an additional vibration excitation prevented by burning the already injected fuel becomes. This will avoid unnecessary kinetic energy is introduced into the system and thus the internal combustion engine comes to a standstill faster. Finally, the achieved Saugrohrdruck a second negative pressure threshold PS3, which not further can be fallen below.

By targeted single injections and ignitions or one Deceleration by the generator, which in this phase out t2 to t4, the internal combustion engine can be brought to be that she runs into a regulated storage area, with it the following startup can be carried out optimally. One Targeted parking can be used for quick start procedures can be used up to the direct start.

In a given by a time interval time t4 are through the engine control initiated start-up measures. These are designed such that the closed throttle fully open again at startup the engine again to have ambient pressure Pu in the intake manifold. As soon as the pressure Ps in the intake manifold reaches a predetermined third pressure threshold, So if ambient pressure has reached Pu, the throttle will return closed. As a start-up measure can also when detected driver stop request, so from the time t1 on in a fuel supply pipe increases existing fuel pressure become.

By this division of Abschaltmaßnahmen in preparatory shutdown and remaining Abschaltmaßnahmen, which can be made only when all shutdown conditions, and the inventive change in the intake manifold pressure is a very fast Lere and more comfortable automatic shutdown of the engine and a greater fuel and emission savings potential possible.

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• - DE 10161343 A1 [0003]

Claims (11)

Engine control for controlling an automatic shutdown of an internal combustion engine with direct injection, wherein the engine control by appropriate shutdown automatically shuts off the engine when all predetermined shutdown conditions are met, characterized in that the Abschaltmaßnahmen be divided into preparatory shutdown and remaining Abschaltmaßnahmen and the engine control upon detection of a driver stop request Such preparatory shut-off action is to reduce the intake pipe pressure (Ps) existing in a suction pipe. Motor control according to Claim 1, characterized that the intake manifold pressure (Ps) is reduced by a Time of recognition of the driver stop request operated in shift operation Internal combustion engine is switched to the homogeneous operation and / or that a throttle class present in the intake manifold is controlled in such a way will reduce the air flow in the intake manifold. Motor control according to Claim 1 or 2, characterized that the engine control Derar term when detected driver stop request preparatory shutdown measures that one in the motor vehicle Existing exhaust gas recirculation valve closed and / or that a variable camshaft adjusting device present in the motor vehicle is brought into its final position and / or the one in a fuel supply pipe present fuel pressure is increased (d_K) and / or that an ancillary load present due to active ancillaries will reduce. Motor control according to one of the preceding claims, characterized in that the remaining shutdown measures be made when a present in the intake manifold intake manifold pressure (Ps) reaches a predetermined first negative pressure threshold (Ps2) or has fallen below and / or if a predetermined first time interval from Time of recognition of the driver stop request exceeded was and / or when the internal combustion engine at the time of Detecting the driver stop request was in homogeneous operation and / or if the air mass in the suction system a predetermined air mass limit has reached or fallen short of. Motor control according to one of the preceding claims, characterized in that motor control such first remaining Abschaltmaßnahmen undertakes that an existing throttle class is closed and / or that the ignition of a existing ignition system is retarded and / or that an existing and deactivated generator is activated becomes. Motor control according to one of the preceding claims, characterized in that the engine control such second residual shutdown does that fuel injection is stopped and / or the ignition is switched off when a present in the intake manifold intake manifold pressure (Ps) a predetermined second negative pressure threshold (Ps3) has reached. Motor control according to one of the preceding claims, characterized in that the engine control within a Time window, the time (t1), from the driver stop request is detected, starts, and at the time by the internal combustion engine is switched off (t3), ends, start-up measures performs. Motor controller according to Claim 7, characterized that the engine control is recognized as ready to start when the driver is stopped Measure a present in a fuel supply pipe Fuel pressure increased. Motor control according to Claim 7 or 8, characterized that the engine control in a motor vehicle with a hybrid Drive unit during a shutdown of the internal combustion engine as start-up measure the internal combustion engine stores in a predetermined crankshaft angle position. Motor control according to one of the claims 7 to 9, characterized in that the engine control such prepares to take preparatory measures that a closed Throttle is opened and / or in a fuel supply pipe existing fuel pressure is increased. Motor controller according to Claim 10, characterized that the opened throttle is closed again, when the intake pipe pressure (Ps) a predetermined third pressure threshold (Pu) has reached or exceeded.