DE102005050785A1 - Internal combustion engine controlling method for motor vehicle, involves applying phase difference to set point air charge, when torque is reduced, so that real torque based on air charge is more than real torque based on ignition angle - Google Patents

Abstract

The method involves applying a phase difference to set point air charge or corresponding variable, when a set point torque is reduced, so that real torque based on the air charge is more than real torque based on ignition angle. The set point air charge or corresponding variable is subjected to positive phase difference if the set point torque has a positive gradient. Independent claims are also included for the following: (1) a computer program to apply an internal combustion engine controlling method (2) an electric storage medium with a computer program for an adjusting and/or control equipment of an internal combustion engine of a motor vehicle (3) an adjusting and/or control equipment of an internal combustion engine of a motor vehicle.

Description

The The invention relates to a method for operating an internal combustion engine of a motor vehicle according to the preamble of claim 1. Subject matter The invention further includes a computer program, an electrical Storage medium and a control and / or regulating device according to the preambles of the independent claims.

at Motor vehicles with automated manual transmissions or with automatic transmissions is to one as possible enable a smooth transition from one gear to the other the torque of the internal combustion engine at a requested gear change first lowered below the driver's requested torque and after the gear change again to the level desired by the driver raised. For this purpose, a setpoint torque is specified accordingly, and by adjusting a throttle and a firing angle an actual torque is tracked as well as possible the desired torque.

Further It is known that a quick torque change through an adjustment the throttle alone is difficult to impossible, since the entering into the combustion chambers air filling the position of the throttle due to the in the intake pipe between Throttle and combustion chambers existing air volume only with a certain delay or inertia follows.

In the DE 102 25 448 A1 Therefore, it is proposed to specify a torque reserve during a shift by the throttle valve is opened more than would be required for the achievement of the desired torque, and in turn the firing angle is adjusted so that the actual torque as well as the target Torque corresponds. If the setpoint torque suddenly increases sharply, the actual torque can be tracked to the setpoint torque without time delay by a corresponding adjustment of the ignition angle.

From the DE 42 32 973 A1 It is also known to start the opening of the throttle before the setpoint torque increases, and at the same time retard the firing angle so as to have a certain torque reserve when the setpoint torque increases. In this way, the actual torque can well follow the setpoint torque.

task The present invention is to provide a method which just works and makes it possible an actual torque follows a setpoint torque as exactly as possible.

These The object is achieved by a method having the features of the claim 1 solved. Further solutions can be found in the independent claims which are a computer program, an electrical storage medium, as well as a control and / or regulating device affect. Advantageous developments of the invention are specified in subclaims.

Advantages of invention

at the method according to the invention In a simple way, a torque reserve is created. This means that in any case for the ignition angle sufficient Adjustment range available stands to the actual torque as possible good track the target torque. This is achieved by the air filling or a corresponding Size, for example one on the air filling based setpoint torque applied with a positive offset becomes. In the episode opens the Throttle, which is a deviation of the air filling based Actual torque resulting from the desired torque. So that still the actual torque the desired torque as well as possible follows, the ignition angle must be to deteriorate by a corresponding value. As a result, the firing angle be sufficiently adjusted in both directions, so that the actual torque good to follow the setpoint torque.

Just in the case of a gear change, the phase of the torque increase is after a previous lowering particularly critical, since it so far here due to inertia The air system in the prior art could occur that a sufficient Adjustment range of the ignition angle no longer existed. This is due to that variant of the method according to the invention excluded, in which the desired air filling or the corresponding Size then is applied with the positive offset when the target torque has a positive gradient, so if the torque increase requested becomes. Before that, such an offset does not exist, so that the internal combustion engine until then with the in this operating condition best Efficiency works.

In a further development, it is also proposed that the desired air charge or the corresponding variable is only supplied with the positive offset if the positive gradient is present for a certain period of time and / or has at least a certain amount. In this way, an unwanted use of the offset, for example, in normal fluctuations avoided the desired torque. As a result, the internal combustion engine only works with the deteriorated by the offset efficiency, if this is really necessary.

Of the Period during which a positive gradient must be present in order to supply the air with to provoke the positive offset, preferably depends on the amount of the gradient. In other words, a flat gradient must be longer present as a steep gradient, to the admission of the desired air filling with to provoke the positive offset.

alternative to trigger the offset by a positive gradient the desired torque may be the desired air charge or the corresponding Size too On request, in particular a transmission control unit, with be applied to the positive offset. This allows a early and especially precise Triggering of offset application (predication).

Of the Offset can be influenced by a gearbox control unit. For example For example, the offset may depend on the gradient of the desired torque. For this is a corresponding, the desired torque or its gradient characterizing size together For example, fed with the speed of the internal combustion engine in a map, which then outputs the offset or an influencing variable. The precision the method according to the invention is then particularly high.

The inventive method allowed over it In addition, a reduction in the example of a transmission control unit to a Motor control unit to be transmitted Dates. For example, simply the setpoint torque whose Course for the actuation of the offset is the cause, specified by the transmission control unit become.

Of the Extent of the offset may depend on the speed, because this affects again the inertia of the air system. The lower the inertia is to be expected, the less the offset may be lower. This helps an unnecessary efficiency deterioration to avoid.

drawing

following become particularly preferred embodiment the present invention with reference to the accompanying Drawing closer explained. In the drawing show:

1 a schematic representation of an internal combustion engine with a transmission, an ignition system, and a throttle valve;

2 a diagram in which different torques during a switching operation of the transmission of 1 are plotted over time;

3 a diagram in which a position of the throttle of 1 according to the switching process of 2 is plotted over time;

4 a representation similar 3 a firing angle;

5 a diagram similar 2 for a second type of gear change.

description the embodiments

In 1 an internal combustion engine carries the reference number 10 , A connected to this transmission the reference numeral 12 , and a motor vehicle indicated only schematically by a dashed line into which the internal combustion engine 10 and the gearbox 12 are incorporated, the reference numeral 14 ,

From the internal combustion engine 10 is an example of a cylinder with a combustion chamber 16 and a piston 18 shown. Combustion air enters the combustion chamber 16 via an inlet valve 20 , which with an inlet channel 22 connected is. In this is a throttle 24 arranged through which the in the combustion chamber 16 reaching air volume can be adjusted. This is the throttle 24 with an adjusting device 25 connected. The hot combustion gases are removed from the combustion chamber 16 via an exhaust valve 26 in an exhaust pipe 28 dissipated. The ignition of one in the combustion chamber 16 existing fuel-air mixture is carried out by a spark plug 30 that of an ignition system 32 is controlled.

By the piston 18 becomes a crankshaft 34 in rotation, in turn, with the gearbox 12 connected is. The speed of the crankshaft 34 is from a speed sensor 36 , the gear position of the transmission 12 from a transmission sensor 38 detected. The position of the throttle 24 is from a throttle sensor 40 captured, and through the inlet duct 22 flowing air flow from an HFM sensor 42 ,

The operation of the internal combustion engine 10 is controlled by a control device 44 controlled and regulated, which is hereinafter referred to as engine control unit. The engine control unit 44 receives, for example, the signals of the HFM sensor 42 and the throttle valve sensor 40 and the shoot speed sensor 36 , and it receives signals from a control device 46 which the transmission 12 controls and therefore hereinafter referred to as transmission control unit.

To when changing gear of the transmission 12 To avoid a shift shock, the engine control unit 44 from the gearbox control unit 46 then, when a gear change is due, instructed, a target torque M _soll to one from the driver of the motor vehicle 14 to lower expressed torque _request M _fawu (compare dashed curve in 2 ). This lowering of the setpoint torque M _soll starts at a time t ₁ . How out 3 shows, this is the angle WDK the throttle 24 decreases linearly from a value WDK ₁ to a value WDK ₂ , the throttle 24 So closed, according to a specification of a based on the air filling torque ML _should (hereinafter called target air moment).

Using the dash-dotted line in 2 it can be seen that the air charge based on the actual torque ML _is (actual air moment hereinafter referred to) due to the inertia of the throttle by the 24 , the inlet channel 22 , the inlet valve 20 and the combustion chamber 16 formed air system the target air torque ML _should follow only with a certain delay. One therefore also speaks of the fact that the "fill-based torque path" is inert.

For setting the actual torque M of the internal combustion _engine 10 but is still a second torque path available, namely an ignition-based torque path. The torque of the internal combustion engine 10 Namely, not only known about the set air filling of the combustion chambers 16 , but also about the ignition angle ZW ( 4 ). Normally, the ignition angle ZW is chosen so that the internal combustion engine 10 has an optimal efficiency so as to minimize fuel consumption. However, the efficiency can be artificially deteriorated, for example, by an adjustment of the ignition angle ZW to late, thereby the actual torque M _is the internal combustion engine 10 to influence.

In the context of this ignition-based torque path, a target torque MZ _soll (hereinafter nominal ignition torque) based on the ignition is set equal to the target torque M _soll . The ignition angle ZW in 4 will now be adjusted continuously so that an in 2 dotted shown ignition-based actual torque MZ _is , which corresponds to the actually performed actual torque M _ist , as well as possible the target ignition torque MZ _{is to} follow. The extent of this required retardation of the ignition angle ZW corresponds qualitatively in about the distance .DELTA.M between the actual ignition torque MZ _is (dotted line in 2 ) and the actual air torque ML _is (dash-dotted line in 2 ). It can be seen that at the time t _1, the ignition angle ZW drops abruptly to a maximum minimum value ZW _min .

However, the target air torque ML _{is to be} limited downwards by a minimum possible air torque ML _min , which is the position WDK _{2 of} the throttle 24 equivalent. This position reaches the throttle 24 at time t ₂ . In order to nevertheless a value below ML _min value M _switching the target torque M _soll. as from the transmission control unit 46 required to achieve the firing angle ZW remains even then compared to the base ignition angle ZW _opt retarded if at time t _3, the actual air torque ML _is again the target air torque ML _should correspond.

When the gear change is done, the transmission control unit 46 At time t _4, an increase in the setpoint torque M _soll back to that of the driver of the motor vehicle 14 desired torque M _fawu approved or required. From the time t ₄ thus has the desired torque M _to a positive gradient. In the engine control unit 44 Now the amount of the gradient dM / dt is determined and from this again a period xt is determined, during which the positive gradient dM / dt must at least be present.

If this condition is met, the target air torque ML _{soll is} acted upon by a positive offset OS at time t ₄ and, starting from this new start value ML _os, linearly applied to that by the driver of the motor vehicle 14 desired desired torque M _fawu returned. This leads to a sudden adjustment of the throttle 24 from the minimum value WDK ₂ to the value WDK _os , from which the angle WDK of the throttle valve 24 is returned to the initial value WDK ₁ . This he reaches at the time t ₅ .

Now again the inertia of the air system makes itself felt, which leads to the fact that the actual air torque ML _is the target air torque ML _should follow only delayed. Due to the offset OS but the distance between the actual air moment ML _and the actual ignition moment MZ _is sufficiently large that the ignition angle ZW ( 4 ) is also in this phase in a middle range between the optimum ignition angle ZW _opt and the latest possible ignition angle ZW _min .

The firing angle can thus be adjusted in this phase, in both directions, which _is a precise adaptation of the actual ignition moment MZ or of the actual torque M _{is to} approach the target torque M possible. At a time point t ₆ all torques M are again identical to that of the driver of the motor vehicle 14 desired torque M _fawu , and the ignition angle is again in the range of the optimal ignition angle ZW _opt .

In 5 is a diagram similar to 2 shown in another shift of the transmission 12 , Unlike in the 2 to 4 shown switching operation achieved in this switching operation, the target air torque ML _{should not} the minimum possible air torque ML _min . In this case, the meaning of the offset OS is particularly well recognizable: Only on the basis of the offset OS, the actual air torque ML _is after the time t ₄ a clear distance ΔM from the actual ignition torque MZ _is on. Thus, the ignition angle _is retarded, which makes it possible, the actual torque M _is very precise track the desired torque M soll.

The difference DM between the actual air moment _{ML and} the actual ignition moment MZ thus does not constitute a torque reserve, which _is for the most accurate tracking of the actual torque M can be used. One recognizes 5 also that the offset OS used there is smaller than that of 2 , This is related to the fact that the amount of offset OS from the current speed of the internal combustion engine 10 depends.

In the embodiment described above, the offset OS _is "triggered" at a positive gradient of the setpoint torque M _soll observed during a certain period of time xt. It is also possible that the application of the desired air torque ML _should with the offset OS by an explicit request, such as a trigger signal of the transmission control unit 46 is triggered. In this case, the size of the offset OS of the transmission control unit 46 to be influenced. For example, the offset OS may depend on the gradient of the setpoint torque M _soll . For this purpose, a variable which characterizes the gradient dM _soll / dt is combined, for example, with the rotational speed of the internal combustion engine 10 fed into a map, which then outputs the offset OS or a size influencing this.

Claims (11)

Method for operating an internal combustion engine ( 10 ) of a motor vehicle ( 14 ), In which a target torque (for a gear change M _soll) with respect to a driver's desired torque (M _FAWU) is lowered, characterized in that in the lowered target torque (M _soll), a target air charge or a corresponding variable (ML _soll) is acted upon with an offset (OS), such that a system based on the air charge actual torque _(ML) is greater than one on the ignition angle (ZW) based actual torque _(MZ). A method according to claim 1, characterized in that the desired air charge or the corresponding size (ML _soll ) is then acted upon by the positive offset (OS) when the desired torque (M _soll ) has a positive gradient (dM / dt) , Method according to Claim 2, characterized in that the desired air charge or the corresponding variable (ML _soll ) is only supplied with the positive offset (OS) if the positive gradient (dM / dt) is present during a specific time period (xt) and / or at least a certain amount. Method according to claim 3, characterized the period (xt) depends on the amount of the gradient (dM / dt). A method according to claim 1, characterized in that the desired air filling or the corresponding size (ML _soll ) on request, in particular a transmission control unit ( 46 ), the positive offset (OS) is applied. A method according to claim 5, characterized in that the size of the offset (OS) of a transmission control unit ( 46 ) being affected. Method according to one of the preceding claims, characterized in that the setpoint torque (M _soll ) from a transmission control unit ( 46 ) is given. Method according to one of the preceding claims, characterized in that the offset (OS) from the current speed and / or a gradient (dM _to / dt) of the target torque (M _soll) is dependent. Computer program, characterized in that it programmed for use in a method according to any one of the preceding claims. Electrical storage medium for a control and / or regulating device ( 44 ) an internal combustion engine ( 10 ) of a motor vehicle ( 14 ), characterized in that on it a computer program for use in a method of claims 1 to 8 is stored. Control and / or regulating device ( 44 ) for an internal combustion engine ( 10 ) of a motor vehicle ( 14 ), characterized in that it is programmed for use in a method according to one of claims 1 to 8.