EP1375859B1 - Method for controlling an internal combustion engine with a gas-dynamic pressure-wave machine - Google Patents

Description

The present invention relates to a method for controlling an internal combustion engine with a gas-dynamic pressure wave machine according to the preamble of claim 1. A gas-dynamic pressure wave machine which is intended to supply charge air to an internal combustion engine is known from WO 99/11913 of the same applicant. In particular, a rotatable air housing is disclosed therein for aligning the ports of one of the two high pressure ports with respect to the other ports of the other high pressure port to achieve process calibration across the full map range of the internal combustion engine and variable width adjustment of the high pressure exhaust port and other features.

Furthermore, from the publication "Modeling and Model-based Control of Supercharged SI Engines" from the laboratory for combustion engines of the Swiss Federal Institute of Technology in Zurich is known to make certain measurements on a gas-dynamic pressure wave machine, based on the above-mentioned patent application.

One can first roughly classify the driving behavior in two stages, i. the acceleration and braking level as well as the constant level. In the first stage, a distinction is made between two phases, a positive load step when accelerating and a negative load step when decelerating or decelerating. The second stage can be divided into three phases, partial load phase, idle phase and constant full load phase.

The present invention relates in particular to the positive load step when accelerating and the negative Loss of load when removing the gas or braking with subsequent partial load behavior.

Experiments have shown that to the air side of the gas-dynamic pressure wave machine penetrating exhaust gases due to false speeds, wrong housing rotation, closed throttle, too strong closed or hanging width adjustment of the high pressure exhaust duct or variable gas pocket inflow or incorrectly set efficiency increase by using a bypass line between the fresh air and exhaust part , The pressure wave loader may be damaged, for example, the storage of the rotor is disturbed by streaks on the housings or by high exhaust gas recirculation and / or low boost pressure and / or high charge air temperature of the engine operation.

From these studies it follows that with respect to the above-mentioned phases a certain order with respect to the control of the individual operations is advantageous, and it is the object of the present invention to avoid the above-mentioned disturbances or damage to the gas-dynamic pressure wave machine, and to achieve higher performance and lower consumption. The object is achieved by the method for controlling according to claim 1.

Figur 1

zeigt schematisch und teilweise im Schnitt ein Ausführungsbeispiel einer gasdynamischen Druckwellenmaschine,

Figur 2

zeigt in perspektivischer Sicht die gasdynamische Druckwellenmaschine gemäss Figur 1, und die

Figuren 3, 3A

zeigen schematisch ein Detail eines abgewickelten zylindrischen Schnittes durch die Zellen eines Rotors einer Druckwellenmaschine mit variabler Verbreiterung des Hochdruck-Abgaskanals.

The invention will be explained in more detail below with reference to drawings of exemplary embodiments. The technical details of the internal combustion engine and the gas dynamic pressure wave machine are detailed in the WO 99/11913 and WO 99/11915 of the same applicant and it is expressly referred to. In particular, the features with the rotation of the housing, in particular air housing, the gas-dynamic pressure wave machine in order Tuning of the two high-pressure exhaust gas channels, to the connecting line between the high-pressure charge air duct and the high-pressure exhaust passage and the variable broadening of the high-pressure exhaust passage or the variable gas pocket inflow reference.

FIG. 1

shows schematically and partially in section an embodiment of a gas-dynamic pressure wave machine,

FIG. 2

shows a perspective view of the gas-dynamic pressure wave machine according to Figure 1, and the

FIGS. 3, 3A

12 schematically show a detail of a developed cylindrical section through the cells of a rotor of a pressure wave machine with variable broadening of the high-pressure exhaust gas duct.

In Figures 1 and 2, a gas-dynamic pressure wave machine is shown, on which a variety of improvements have been carried out in order to increase the overall efficiency significantly. The pressure wave machine 30 is connected via the high-pressure exhaust passage 31 and the high-pressure charge air passage 32 with the combustion engine 33 shown schematically. In the gas housing 34 is also the low-pressure exhaust passage 35, and it can be seen from this figure that the two channels, ie the high-pressure exhaust passage and the low-pressure exhaust passage in the gas housing rotor side as sector-shaped openings 36 A and 37 A, each with an opening edge 36th or 37, see also Figures 5 and 6. It also recognizes the rotor 40th with its cells 41, wherein the rotor is arranged in a jacket 42 and is driven for example by a belt drive 43.

It is initially desirable to tailor the alignment of the opening edges of the high-pressure exhaust gas channel with respect to the opening edges of the high-pressure charge air duct, so that the so-called primary shaft, which is formed when the high-pressure exhaust duct is opened to the rotor chamber at lower pressure, is precisely tuned, such that when it enters the high-pressure charge air duct to the rotor cell on the air side arrives. Previously, attempts were made to achieve this optimization by providing rotatable disks with openings on the housings in order to influence the two high-pressure flows.

In the present embodiment, the opening edges of the high-pressure charge air passage 32, d. H. the opening into the rotor cells openings, adjusted by either the air housing with respect to the stationary rotor and gas housing or only the high-pressure charge air duct is rotated. As a result, the opening edges of the two high-pressure channels can always be adjusted to one another at each characteristic point point of the internal combustion engine so that the primary shaft can fulfill the above-mentioned condition. The rotation of the housing can be, for example, 0-25 °.

By a direct supply of fresh air into the exhaust duct, a large increase in performance can be achieved. It can be seen in Figures 1 and 2, the connecting line 46 which leads from the high-pressure charge air duct into the high pressure exhaust duct. As a result, the positive pressure surges in the Transfer high-pressure charge air duct to the high-pressure exhaust duct. The connecting line includes a check valve 47, which is optionally provided with an electronic control. In this case, the check valve acts as a control in the sense that only pressure surges are transmitted, the energy level is higher than the current pressure in the high-pressure exhaust passage. In particular, the negative pressure pulses, ie the state of the quasi negative pressure in the high-pressure exhaust gas channel, are raised, and the entire pressure level is raised both within the high-pressure exhaust gas channel and the high-pressure charge air channel by the smoothing of the negative pressure pulses. As a result, the pressure level in the rotor can be significantly increased before opening the high-pressure exhaust gas channel, and the pulsations arriving from there are damped. In addition, this measure reduces the Einströmverluste the hot exhaust gas into the rotor, since the entire process is damped.

A further improvement can be achieved if the branch, which is located somewhere between the high-pressure charge air duct edge and the engine intake in FIG. 1 or 2, is arranged directly after the opening edge of the high-pressure charge air duct. This preferred variant is not shown in FIG. 1 for the sake of clarity.

As already mentioned, the pressure wave machine according to the prior art is highly filling-dependent. In addition to reducing the pressure pulsations, as described above, the provision of a connecting line allows the return of charge air to the high-pressure exhaust side of the pressure wave machine, thereby increasing the Mass flow rate of the machine and thus an increase in the degree of filling, which is noticeable in a significant increase in pressure. An additional control of the recirculated fresh air high pressure by means of a regulated check valve can thus be used for boost pressure control in general and the gasoline engine in addition to power control. In other words, in order to improve the compression efficiency, the pressure wave machine can be dimensioned somewhat larger at higher engine throughputs without losing boost pressure at lower engine throughputs.

This can also be done, for example, by regulating the cross-section of the connecting channel by means of a suitable, known device, whereby either the controlled non-return valve or an additional cross-sectional control can be used. This is particularly effective in the low to medium speed, temperature and load range of the internal combustion engine. This means that the system for increasing the power by means of a connecting line is a tool for a possibly too low achievable boost pressure at low engine speeds, from 1'000 to 3'000 RPM, a strong increase of the boost pressure by exploiting the exhaust gas pulsations and the positive pressure difference across the pressure wave machine to reach.

The use of a connecting line between the fresh air and exhaust part causes a considerable increase in efficiency in otherwise known pressure wave machines, but is particularly effective in conjunction with the aforementioned and described measures to improve the efficiency. This power increase should be able to be effected via the motor control with an actuator with an open-close function.

Figures 3 and 3A relate to another aspect of the pressure wave machine, to the influence of the high-pressure exhaust stream. In FIGS. 3, 3A, an influencing of the high-pressure exhaust gas channel, or its widening, is shown schematically. Therein, the unwound rotor 40 is shown with the cells 41 and a recess 48 is provided in the gas housing 34, which can be changed by a slider 49, as indicated by the arrow 50. In FIG. 3A, the slide 49 is fully engaged in the direction of the arrow, so that the high-pressure exhaust gas channel is broadened without a web being created. By a suitable and calculable for a professional control of the slide can be moved so that the high-pressure channel is widened until the pressure has dropped so far that the charge pressure generated by the pressure wave process drops to the desired level.

Analogously, if the widening of the high-pressure exhaust gas channel is not selected, the gas pocket inflow can be varied in a manner known per se, albeit less effectively, since a web remains.

As mentioned in the introduction, a number of sources of error are known which can interfere with the operation of the internal combustion engine or damage the gas-dynamic pressure wave machine. For this reason, a particular order in the regulation of a pressure wave supercharger in each map range of the internal combustion engine makes sense.

That is, for each map point positioning and an order of operation of the existing actuators could be described. However, since this results in an endless series, a total of two adjustment options are selected: When increasing the power of the internal combustion engine, simply expressed when accelerating, and when removing the gas or braking.

1. 1. Die Spülluftklappe 59, siehe Figur 1, im Ansaugkanal vor der Druckwellenmaschine muss beim Beginn des Lastsprungs mit geeigneten Mitteln, beispielsweise E-Steller oder Kabelzug, sofort so weit wie möglich geöffnet werden, damit der erhöhte Luftdurchsatz durch die Druckwellenmaschine gewährleistet werden kann.
2. 2. Die Drehzahl und die Verdrehung des Gehäuses, insbesondere des Luftgehäuses 39, der Druckwellenmaschine müssen mit geeigneten Mitteln auf die im Kennfeld abgespeicherte optimale Position relativ zum Kennfeldpunkt der Verbrennungsmaschine bewegt werden.
3. 3. Der Schieber der variablen Breiteverstellung des Hochdruck-Abgaskanals oder des variablen Gastaschenzuflusses muss auf die im Kennfeld abgespeicherte Position gestellt werden bzw. auf den aus dem Motorkennfeld benötigten Ladedruck eingeregelt werden.
4. 4. Das Ventil der Verbindungsleitung 46 zwischen dem Hochdruck-Ladeluftkanal und dem Hochdruck-Abgaskanal kann bei nicht Erreichen des gewünschten Ladedruckes zusätzlich geöffnet werden, vorteilhafterweise nur zwischen N_mot = 1'000 - 3'000 U/Min.
5. 5. Die variable Breiteverstellung des Hochdruck-Abgaskanals oder der variable Gastaschenzufluss wird daraufhin die Funktion der Druckregelung gemäss Fahrerwunsch übernehmen.

In the following, an example of a control at a positive load step, ie when accelerating given, with the throttle of the engine or the control rod in the diesel engine depending on the driver's request for more power via a cable or an e-gas opened, or the control rod is moved ,

1. 1. The purge air flap 59, see Figure 1, in the intake duct before the pressure wave machine must be opened as soon as possible at the beginning of the load jump with suitable means, such as e-controller or cable, so that the increased air flow can be ensured by the pressure wave machine.
2. 2. The speed and the rotation of the housing, in particular of the air housing 39, the pressure wave machine must be moved by suitable means to the stored in the map optimal position relative to the map point of the internal combustion engine.
3. 3. The variable width adjustment valve of the high-pressure exhaust gas channel or the variable gas pocket inflow must be set to the position stored in the map or adjusted to the boost pressure required from the engine map become.
4. 4. The valve of the connecting line 46 between the high-pressure charge air duct and the high-pressure exhaust gas channel can be additionally opened at not reaching the desired boost pressure, advantageously only between N _mot = 1'000 - 3'000 U / min.
5. 5. The variable width adjustment of the high-pressure exhaust gas channel or the variable gas pocket inflow will then take over the function of pressure regulation according to the driver's request.

It should be noted that the check valve of the connecting line may only be opened when all other parameters and actuators are already in the optimum position after the positive load step, because of the requirement of the highest possible boost pressure. This is necessary because with the power boost system, the high pressure process is increased at the expense of the purge process.

1. 1. Bei negativem Lastsprung mit einer Anforderung eines tieferen Ladedrucks muss die Verbindungsleitung sofort und als erstes wieder geschlossen werden. Das Ventil der Verbindungsleitung muss garantiert geschlossen sein.
2. 2. Bei der Verdrehung des Gehäuses und Einstellen der Drehzahl der Druckwellenmaschine sollten diese Werte eine optimale Position aus den im Motorversuch aufgenommenen und im Kennfeld abgespeicherten Werten aufweisen.
3. 3. Die Spülluftklappe 59 der Druckwellenmaschine sollte möglichst weit geschlossen werden, jedoch nur soweit, dass die Rotorspülung nicht zusammenbricht. Dies erfordert Sensoren bei der A-Sonde und Messung der Abgastemperatur nach der Druckwellenmaschine.
4. 4. Der Schieber der variablen Breiteverstellung des Hochdruck-Abgaskanals oder des variablen Gastaschenzuflusses sollte möglichst weit geöffnet sein, so dass die Druckdifferenz zwischen Hochdruckladeluft und Hochdruckabgas möglichst gering ist.

When regulating the pressure wave machine with a negative load step, ie when removing the gas, with subsequent partial load behavior, the following sequence should be observed:

1. 1. If there is a negative load jump with a request for a lower charge pressure, the connection line must be closed immediately and first. The valve of the connecting line must be guaranteed to be closed.
2. 2. When turning the housing and adjusting the speed of the pressure wave machine, these values should be an optimal position from that in the engine test recorded and stored in the map values.
3. 3. The purging air flap 59 of the pressure wave machine should be closed as far as possible, but only to the extent that the rotor purging does not collapse. This requires sensors in the A-probe and measurement of the exhaust gas temperature after the pressure wave machine.
4. 4. The slider of the variable width adjustment of the high-pressure exhaust gas passage or the variable gas pocket inflow should be as wide as possible, so that the pressure difference between the high-pressure charge air and high-pressure exhaust gas is minimized.

Experiments have shown that maintaining the above-described sequence in the regulation of the pressure wave machine optimum performance can be achieved with low consumption.

As already mentioned, a positioning as well as an order of operation of the existing actuators could be described for each map point. However, since this is endless, it is convenient to use the principle of optimal positioning according to the map and the readjustment with e.g. Go out PID controllers.

The housing rotation, the speed and position of the high pressure exhaust duct width or variable gas pocket inflow slide may vary as required and produce similar results in different settings. Good results can be achieved by optimizing the performance of the internal combustion engine or its torque when adjusting the pressure wave machine.

As noted in the introduction, this application particularly describes the regulation of the positive and negative load step steps, but it goes without saying that the other three phases mentioned are also optimized for constant driving, in which case there is also a certain order of regulation is made. This regulation of the remaining three phases is then combined with the other regulatory steps with prescribed order.

The inventive method is not limited to the system described combustion engine pressure wave machine. In its basic form, the method is valid for all systems internal combustion engine pressure wave machine. Its full effectiveness unfolds with all options. This method also applies to both gasoline and diesel engines, with and without catalysts and with or without additional heating.

Claims (9)

1. Method for controlling an internal combustion engine with a gas-dynamic pressure-wave machine, wherein the gas-dynamic pressure-wave machine comprises a rotatable housing, in order to adjust the process over the entire characteristic range of the internal combustion engine, and a variable width adjustment of the high-pressure exhaust duct or a variable gas pocket inflow, characterised in that in each characteristic range a specific sequence of control is maintained, wherein with a positive pressure surge

   the speed and the housing of the gas-dynamic pressure-wave machine are adjusted by suitable means to the optimal position stored in the characteristic,

   the variable width adjustment of the high-pressure exhaust duct or the variable gas-pocket inflow is adjusted to the charging pressure required by the engine characteristic; and

   with a negative pressure surge

   the speed and the housing of the gas-dynamic pressure-wave machine are adjusted by suitable means to the optimal position stored in the engine characteristic and

   the variable width adjustment of the high-pressure exhaust duct or the variable gas pocket inflow is opened as far as possible in order to keep the pressure difference from high pressure charging air to high pressure exhaust as low as possible.
2. Method according to claim 1, characterised in that at the beginning of the positive load surge, when the control element of the internal combustion engine is displaced as desired by the driver after more power, firstly a scavenging air flap in the suction port of the gas-dynamic pressure-wave machine is opened as far as possible.
3. Method according to claim 1 or 2, characterised in that with a positive pressure surge and if the desired charging pressure is not achieved a connection line is also opened between the high-pressure charging air duct and the high-pressure exhaust duct.
4. Method according to claim 3, characterised in that the opening is performed within a range of N_mot = 1,000 - 3,000 rpm.
5. Method according to claim 3 or 4, characterised in that the connection line is opened only when all of the other parameters and regulating elements are already in an optimal position after the positive pressure surge.
6. Method according to claim 1 with a negative pressure surge, characterised in that it is ensured that a connection line between the high-pressure-charging air duct and the high-pressure exhaust duct is securely closed.
7. Method according to claim 6, characterised in that a valve is actuated in the connection line via the automatic control of the internal combustion engine by an actuating element.
8. Method according to claim 6 or 7, characterised in that at the beginning of the negative pressure surge the scavenging air flap is closed as far as possible without the rotor scavenging breaking down.
9. Method according to one of claims 1 to 8, characterised in that the rotatable housing of the gas-dynamic pressure-wave machine is the air housing.

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