DE102008026323A1 - Method for variable throttle with which control device has variable valve impulses for four-stroke piston engine, involves absorbing load by variable back thrust control with ambient pressure and with positive pressure - Google Patents

Abstract

The method involves absorbing a load by the variable back thrust control with the ambient pressure and with a positive pressure, into an actuator without changing the intake cross section unthrottled up to the lower dead center. The load absorbing excessively is closed by an inlet valve, opened around a gap, is throttled in a suction device and pushed back till the inlet valve.

Description

It is well known that in gasoline engines combustion through a spark ignition is initiated. The spark ignition requires that a combustion air ratio within the ignition limits the mixture is maintained. To set partial load is the intake cross section through a throttle valve or by a lift-controlled inlet valve reduced, d. H. Throttle control. That is what prevails during the Suction stroke in a working cylinder, at part load operation, a lesser Pressure opposite the ambient pressure, which leads to a decreasing efficiency.

variable Valve drives, d. H. with variable opening time, variable valve lift, reduce by influencing the charge exchange work, the Mixture preparation and combustion fuel consumption of gasoline engines. in principle are the opening and closing times and the maximum valve lift those parameters based on the different derived variation parameters become more variable Derive valve controls. Especially worth mentioning is the continuously variable valve lift function that, in conjunction with a correspondingly changeable Intake-closing time at most effective for Throttle-free load control in gasoline engines can be used. At the same time at full load for each speed set the optimal intake-close timing become. A continuous change the maximum stroke without corresponding change in the opening or Closing times can at best be in a restricted area for generating be used by charge movement. In the load control SES (late Inlet close), too as retraction control (Miller method), an inlet valve remains open beyond bottom dead center. The excess amount of charge will be at the subsequent upward movement of the piston pushed back into the intake tract. this leads to especially at low loads to increased flow losses without these are directly usable for mixture preparation, which has negative effects on performance and torque brings with it. The disadvantage of the lower filling must go through be compensated for a corresponding supercharger.

In The presented invention, the retraction control of another kind presented d. H. variable retraction control.

Unlike throttling regulation, a charge is transferred to a working cylinder ( 1 ) sucked unthrottled without changing the Ansaugquerschnittes. The excess sucked charge is, depending on the engine operating state, by an open by a gap (S ₁ ) inlet valve ( 6 ), throttled into a Saigvorrichtung ( 10 ) is pushed back until this inlet valve is closed. Therefore, at partial load operation in a working cylinder ( 1 ) exert a greater pressure against the pressure in this cylinder at UT, which has a great effect on the density of heat energy. In the throttle-free method of variable retraction control are no longer covered by energy charge losses such. B. a throttle (or stroke-controlled intake valves) and an air mass meter arise. Since the throttle regulation of all kinds is then eliminated, prevails at the intake valves almost ambient pressure and the temperature of the mixture decreases due to the expansion. By varying the internal exhaust gas recirculation, the residual gas content in the working cylinders can be controlled with regard to increased compression ratios and lower exhaust gas values. As a result, improved efficiency, significant fuel savings and lower emissions are expected.

This Principle can not only with gasoline engines but also with diesel engines be applied.

In the present invention, the method of variable retraction control and the control device for the four-stroke reciprocating engines with variable valve trains, in which the Air-fuel ratio through variable retraction control maintained according to an engine operating condition and a reduced pollutant emissions is explained.

In the 1 Working diagrams of the method of variable retraction control, without charging and without exhaust gas recirculation, as an example with 3 closing points, are shown.

a) Lower part-load operation.

• P₁ – Druck in einem Arbeitszylinder bei UT;
• P₂ – Druck in einem Arbeitszylinder bei einem Einlaßschließpunkt;
• OT – oberer Totpunkt;
• UT – unterer Totpunkt.
• V₁ – Zylindervolumen bei dem Einlaßschließpunkt (A₁)

The suction takes place between points 1 and 2. 2 to 3 - Reverse with increasing pressure in a working cylinder. In point 3 - beginning of compression. 3 to 4 - compression. 4 to 5 - ignition and combustion. 5 to 6 - exhaust emissions.

• P ₁ - pressure in a working cylinder at UT;
• P ₂ - pressure in a working cylinder at an inlet closing point;
• OT - top dead center;
• UT - bottom dead center.
• V ₁ - cylinder volume at the inlet closing point (A ₁ )

b) Part load operation.

• P₁ – Druck in einem Arbeitszylinder bei UT;
• P₂ – Druck in einem Arbeitszylinder bei einem Einlaßschließpunkt;
• OT – oberer Totpunkt;
• UT – unterer Totpunkt.
• V₂ – Zylindervolumen bei dem Einlaßschließpunkt (A₂)

The suction takes place between points 1 and 2. 2 to 3 - Reverse with increasing pressure in a working cylinder. In point 3 - beginning of compression. 3 to 4 - compression. 4 to 5 - Zün and combustion. 5 to 6 - exhaust emissions.

• P ₁ - pressure in a working cylinder at UT;
• P ₂ - pressure in a working cylinder at an inlet closing point;
• OT - top dead center;
• UT - bottom dead center.
• V ₂ cylinder volume at the inlet closing point (A ₂ )

c) full load operation.

• P₁ – Druck in einem Arbeitszylinder bei UT;
• OT – oberer Totpunkt;
• UT – unterer Totpunkt.
• V₃ – Zylindervolumen bei dem Einlaßschließpunkt (A₃)

The suction takes place between points 1 and 2. The compression starts from UT, ie between points 2 and 4. 4 to 5 - Ignition and combustion. 5 to 6 - exhaust emissions.

• P ₁ - pressure in a working cylinder at UT;
• OT - top dead center;
• UT - bottom dead center.
• V ₃ - cylinder volume at the inlet closing point (A ₃ )

In the 2 are shown working diagrams of the method of variable retraction control, with charging and without exhaust gas recirculation, as an example with 3 closing points.

a) Lower part-load operation.

• P₁ – Druck in einem Arbeitszylinder bei UT;
• P₂ – Druck in einem Arbeitszylinder bei einem Einlaßschließpunkt;

The suction of the intake air with overpressure takes place between points 1 and 2. 2 to 3 - Reverse with increasing pressure in a working cylinder. In point 3 - beginning of compression. 3 to 4 - compression. 4 to 5 - ignition and combustion. 5 to 6 - exhaust emissions.

• P ₁ - pressure in a working cylinder at UT;
• P ₂ - pressure in a working cylinder at an inlet closing point;

b) Part load operation.

• P₁ – Druck in einem Arbeitszylinder bei UT;
• P₂ – Druck in einem Arbeitszylinder bei einem Einlaßschließpunkt;

The suction of the intake air with overpressure takes place between points 1 and 2. 2 to 3 - Reverse with increasing pressure in a working cylinder. In point 3 - beginning of compression. 3 to 4 - compression. 4 to 5 - ignition and combustion. 5 to 6 - exhaust emissions.

• P ₁ - pressure in a working cylinder at UT;
• P ₂ - pressure in a working cylinder at an inlet closing point;

c) full load operation.

• P₁ – Druck in einem Arbeitszylinder bei UT;

The suction of the intake air with overpressure takes place between points 1 and 2. The compression starts from UT, ie between points 2 and 4. 4 to 5 - Ignition and combustion. 5 to 6 - exhaust emissions.

• P ₁ - pressure in a working cylinder at UT;

In the 3 An embodiment of a schematic assembly of an engine system with variable valve trains and direct injection is shown.

By the rotational movements of a crankshaft ( 4 ), a piston ( 2 ) via a connecting rod ( 3 ) and into a combustion chamber of a working cylinder ( 1 ) is a fresh charge through an inlet device ( 10 ) and via an inlet valve ( 6 sucked unthrottled.

Opposite is a fuel from a pressure pump ( 17 ) put under pressure. In this case, a fuel is supplied to a fuel system, which is an injection device ( 23 ) having. Finally, a fuel is injected into a working cylinder through an injector ( 23 ) and then with a spark plug ( 24 ) ignited, wherein the voltage of a spark plug from an ignition coil ( 16 ) is increased.

The engine speed is determined based on a detection signal received from a crankshaft position sensor (FIG. 5 ) and the engine load is calculated from an engine speed and a parameter corresponding to a fresh charge volume in a cylinder of an engine.

• – ein Signal, das die Steuerungsrate eines Frischladungsvolumens nach einer axialen Stellung einer Einlaßnockenwelle (7) von einem Einlaßnockenwellen-Positionssensor (9) anzeigt;
• – ein Signal, das eine Stellung einer Kurbelwelle (4) von einem Kurbelwellen-Positionssensor (5) anzeigt um eine Drehzahl zu detektieren;
• – ein Signal, das einen Druck in einem Kraftstoffsystem von einem Kraftstoffdrucksensor (22) anzeigt;
• – ein Signal, das eine Stellung einer Auslaßnockenwelle (12) von einem Auslaßnockenwellen-Positionssensor (14) anzeigt;
• – ein Signal, das eine Stellung eines Fahrpedals (18) von einem Fahrpedal-Positionssensor (19) anzeigt;
• – ein Signal von einer Lambda-Sonde (21), die vor einer in einem Auspuff angeordneten Katalysatoreinrichtung (25) angebracht ist.

Meanwhile, a plurality of signals indicative of the control rates are output from various sensors and sent to a control unit (FIG. 20 ) entered:

• A signal representing the rate of control of a fresh charge volume after an axial position of an intake camshaft ( 7 ) from an intake camshaft position sensor ( 9 ) indicates;
• A signal representing a position of a crankshaft ( 4 ) from a crankshaft position sensor ( 5 ) to detect a speed;
• A signal indicative of a pressure in a fuel system from a fuel pressure sensor ( 22 ) indicates;
• A signal indicating a position of an exhaust camshaft ( 12 ) from an exhaust camshaft position sensor ( 14 ) indicates;
• A signal representing a position of an accelerator pedal ( 18 ) from an accelerator pedal position sensor ( 19 ) indicates;
• A signal from a lambda probe ( 21 ) disposed in front of a catalyst device ( 25 ) is attached.

• – an den Verstellmechanismus einer Einlaßnockenwelle (8), wodurch eine Einlaßnockenwelle (7) zu einer Frischladungsvolumenregulierung, entsprechend einem Motorbetriebszustand und einem Schadstoffausstoß, axial verstellt wird;
• – an den Verstellmechanismus einer Auslaßnockenwelle (13) wodurch eine Auslaßnockenwelle (12) zu interner Abgasrückführung, entsprechend einem Motorbetriebszustand und einem Schadstoffausstoß, axial verstellt wird;
• – an eine Zündspule (16);
• – an eine Kraftstoffpumpe (17);
• – an eine Einspritzeinrichtung (23).

Like in the 4 is shown, a control unit ( 20 ) signals output from the various sensors for detecting the operating conditions of an engine. Further, an aforementioned operation by this control unit ( 20 ) and resulting results are used as control signals to the following Einrich issued:

• - to the adjustment mechanism of an intake camshaft ( 8th ), whereby an intake camshaft ( 7 ) is axially displaced to a fresh charge volume regulation corresponding to an engine operating condition and a pollutant emission;
• - to the adjustment mechanism of an exhaust camshaft ( 13 ) whereby an exhaust camshaft ( 12 ) is moved axially to internal exhaust gas recirculation, according to an engine operating condition and a pollutant emission;
• - to an ignition coil ( 16 );
• To a fuel pump ( 17 );
• To an injection device ( 23 ).

In the 4 schematically a block diagram of a control unit in the control device for a variable displacement internal combustion engine with direct injection molding according to the present invention is shown.

• a) Nach den ausgegebenen Steuerungssignalen einer Steuerungseinheit (20) werden die Nockenwellen (7 und 12) durch die Verstellmechanismen der Nockenwellen (8 und 13) entsprechend einem Motorbetriebszustand und einem Schadstoffausstoß zu einem von den Messpunkten (L₁, L₂ oder L₃) der Messpunktwege (L_x(y)) axial verstellt, wodurch die Ventile (6 und 11) in einem von den Schließpunkten E(A)₁, E(A)₂ oder E(A)₃ geschlossen werden. S₁ – ein Öffnungsspalt eines Einlaßventils (Einlaßnockenhub) während der Rückschubphase; S₂ – ein Öffnungsspalt eines Auslaßventils (Auslaßnockenhub) während interner Abgasrückführung.
• b) ein beispielhafter Einlaßnocken mit 3 variabel geformten positiven Führungsbahnen. Phase 1 und Phase 2 – die Rückschubphasen. Die Einlaßnockenhübe für die Rückschubphasen 1 und 2 (beide als S₁ gekennzeichnet) können mit verschiedenen Höhen versehen werden.
• c) ein beispielhafter Auslaßnocken mit 3 variabel geformten positiven Führungsbahnen. Phase 1a und Phase 2a – die Abgasrückführungsphasen.

In the 5 becomes an example of the camshafts ( 7 and 12 ) of variable valve trains with the camshaft position sensors ( 9 and 14 ) and with the valves ( 6 and 11 ).

• a) According to the output control signals of a control unit ( 20 ), the camshafts ( 7 and 12 ) by the adjustment mechanisms of the camshafts ( 8th and 13 ) is axially displaced to one of the measuring points (L ₁ , L ₂ or L ₃ ) of the measuring point paths (L _{x (y)} ) according to an engine operating condition and a pollutant emission, whereby the valves ( 6 and 11 ) in one of the closing points E (A) ₁ , E (A) ₂ or E (A) ₃ . S ₁ - an opening gap of an intake valve (intake cam lift) during the retracting phase; S ₂ - an opening gap of an exhaust valve (exhaust cam lift) during internal exhaust gas recirculation.
• b) an exemplary intake cam with 3 variably shaped positive guideways. Phase 1 and Phase 2 - the repatriation phases. The intake cam lifts for the recoil phases 1 and 2 (both identified as S ₁ ) may be provided with different heights.
• c) an exemplary exhaust cam with 3 variable shaped positive guideways. Phase 1a and Phase 2a - the exhaust gas recirculation phases.

The exhaust cam lifts for the exhaust gas recirculation phases 1a and 2a (both labeled as S ₂ ) may be provided with different heights.

• a) Ohne eine Aufladung.
• b) Mit einer Aufladung.

In the 6 The working diagrams of the method of variable retraction control are compared with the working diagrams of the Miller method at partial load operation.

• a) Without a charge.
• b) With a charge.

Different than in the method of variable retraction control is the Miller method the sucked charge between the points 2 and 3 unused in pushed back the intake system.

• a) Volllastbetrieb ohne den Rückschub und ohne interne Abgasrückführung.
• b) Oberer Teillastbetrieb ohne den Rückschub und mit interner Abgasrückführung (Phase 1a).
• c) Oberer Teillastbetrieb ohne den Rückschub und mit interner Abgasrückführung (Phase 2a).
• d) Mittlerer Teillastbetrieb mit dem Rückschub (Phase 1) und ohne interne Abgasrückführung.
• e) Mittlerer Teillastbetrieb mit dem Rückschub (Phase 1) und mit interner Abgasrückführung (Phase 1a).
• f) Mittlerer Teillastbetrieb mit dem Rückschub (Phase 1) und mit interner Abgasrückführung (Phase 2a).
• g) Unterer Teillastbetrieb mit dem Rückschub (Phase 2) und ohne interne Abgasrückführung.
• h) Unterer Teillastbetrieb mit dem Rückschub (Phase 2) und mit interner Abgasrückführung (Phase 1a).
• k) Unterer Teillastbetrieb mit dem Rückschub (Phase 2) und mit interner Abgasrückführung (Phase 2a).

In the 7 The exemplary control diagrams of the method of variable retraction control are shown.

• a) Full load operation without retraction and without internal exhaust gas recirculation.
• b) Upper part-load operation without retraction and with internal exhaust gas recirculation (phase 1a).
• c) Upper part-load operation without retraction and with internal exhaust gas recirculation (phase 2a).
• d) Medium part-load operation with retraction (phase 1) and without internal exhaust gas recirculation.
• e) Medium part-load operation with retraction (phase 1) and with internal exhaust gas recirculation (phase 1a).
• f) Medium part-load operation with retraction (phase 1) and with internal exhaust gas recirculation (phase 2a).
• g) Lower partial load operation with retraction (phase 2) and without internal exhaust gas recirculation.
• h) Lower part load operation with retraction (phase 2) and with internal exhaust gas recirculation (phase 1a).
• k) Lower part-load operation with retraction (phase 2) and with internal exhaust gas recirculation (phase 2a).

A ₁

Outlet closing point (exhaust gas recirculation phase 2a);

A ₂

Outlet closing point (exhaust gas recirculation phase 1a);

A ₃

Auslaßschließpunkt;

E ₁

Inlet closing point at lower partial load operation (retraction phase 2);

E ₂

Inlet closing point at middle part load operation (reverse phase 1);

E ₃

Inlet closing point at the full load operation;

h _v

valve

L _x

Messpunktweg the intake camshaft;

L _y

Messpunktweg the exhaust camshaft;

L ₁

measuring point 1;

L ₂

measuring point 2;

L ₃

measuring point 3;

OT

upper dead center;

P ₁

print in a working cylinder at UT;

P ₂

print in a working cylinder at an intake closing point;

S ₁

opening gap an intake valve (Einlaßnockenhub) while the reverse phase;

S ₂

opening gap an exhaust valve (Auslaßnockenhub) while internal exhaust gas recirculation.

UT

lower dead center;

V

cylinder volume

V ₁

Cylinder volume at the inlet closing point A ₁

V ₂

Cylinder volume at the inlet closing point A ₂

V ₃

Cylinder volume at the inlet closing point A ₃

1

Working cylinder;

2

Piston;

3

Connecting rod;

4

Crankshaft;

5

Crankshaft position sensor;

6

Inlet valve;

7

Intake camshaft;

8th

adjustment the intake camshaft;

9

Intake camshaft position sensor;

10

suction device;

11

exhaust valve;

12

exhaust;

13

adjustment the exhaust camshaft;

14

Exhaust camshafts position sensor;

15

outlet means;

16

Ignition coil;

17

Fuel pump;

18

Accelerator pedal;

19

Accelerator position sensor;

20

electronic Control unit;

21

Lambda probe;

22

Fuel pressure sensor;

23

Injector;

24

Spark plug;

25

Catalyst device;

26

Intake cam;

27

Exhaust cams.

Claims (10)

The method of variable retraction control, in which the control device for a four-stroke reciprocating engine with variable valve drives, by closing point control of the intake valves ( 6 ) and the exhaust valves ( 11 ) is controlled to a value that is suitable for an engine operating state and for a pollutant emission, characterized by the variable retraction control, in which, a charge, both with the ambient pressure and with an overpressure, in a working cylinder ( 1 ) is sucked unthrottled to bottom dead center without changing the intake cross-section. At partial load operation in the retraction phases, the excess sucked charge by an open by a gap (S ₁ ) inlet valve ( 6 ) throttled into a suction device ( 10 ) is pushed back until this inlet valve is closed. Through this process, a charge pressure, in a working cylinder ( 1 ) increase with increasing density already before an inlet closing point (E ₁ or E ₂ ), whereby a charge in the volume (V ₁ or V ₂ ) of a working cylinder ( 1 ) is pre-compressed. At full load operation, compression begins at bottom intake point at an intake closing point (E ₃ ). The method of the variable recoil control according to claim 1, characterized by the internal exhaust gas recirculation, in which the exhaust gases, in the exhaust gas recirculation phases, by an open by a gap (S ₂ ) exhaust valve ( 11 ) in a working cylinder ( 1 ), in view of increased compression ratios and lower exhaust gas values, are returned until this exhaust valve is closed. The method of the variable recoil control according to claims 1 and 2, characterized by a guard device, which, using the adjusting mechanisms ( 8th and 13 ), the camshafts ( 7 and 12 ) for optimal charge exchange according to a reduced pollutant emissions and an engine operating state axially adjusted. The method of the variable retracting control according to claims 1 to 3, characterized by a control device, wherein a guard means an adjusting mechanism ( 8th ) to an axial displacement (L _x ) of an intake camshaft ( 7 ) attaches to the variable retraction control according to an engine operating condition. The method of the variable retracting control according to claims 1 to 3, characterized by a control device, wherein a guard means an adjusting mechanism ( 13 ) to an axial displacement (L _y ) of an exhaust camshaft ( 12 ) for a reduced pollutant emissions according to a Mototbetriebszustand attaches. The residual gas content in a working cylinder ( 1 ) controlled by the variation of the internal exhaust gas recirculation. The method of the variable recoil control according to claims 1 to 5, characterized by a control method, which, by electronic control unit ( 20 ), the adjusting mechanisms ( 8th and 13 ) for controlling the closing points E (A) ₁ , E (A) ₂ , E (A) _{3 of} the intake valves ( 6 ) and the exhaust valves ( 11 ) to a value suitable for an engine operating condition and for reduced pollutant emissions. The method of the variable retraction control according to claim 6, characterized by a control method, in which a guard device comprises an adjusting mechanism ( 8th ) to an axial displacement (L _x ) of an intake camshaft ( 7 ) for the variable retraction control according to a Engine operating state attaches. The method of the variable retraction control according to claim 6, characterized by a control method, in which a guard device comprises an adjusting mechanism ( 13 ) to an axial displacement (L _y ) of an exhaust camshaft ( 12 ) for a reduced pollutant emissions according to a Mototbetriebszustand attaches. The residual gas content in a working cylinder ( 1 ) controlled by the variation of the internal exhaust gas recirculation. The variable recoil control method according to claim 1, characterized by an intake cam, wherein a stroke of a variable positive guideway for the Push-back phase 1 with a different height as a stroke of a variable positive guideway for the reverse phase 2 can be provided. The variable recoil control method according to claim 2, characterized by an exhaust cam, wherein a stroke of a variable positive guideway for the Exhaust gas recirculation phase 1a with a different height as a stroke of a variable positive guideway for the exhaust gas recirculation phase 2a can be provided.