WO2008095783A2

WO2008095783A2 - Internal combustion engine

Info

Publication number: WO2008095783A2
Application number: PCT/EP2008/050793
Authority: WO
Inventors: Paul Kapus
Original assignee: Avl List Gmbh
Priority date: 2007-02-08
Filing date: 2008-01-24
Publication date: 2008-08-14
Also published as: WO2008095783A3; DE112008000333A5

Abstract

The invention relates to an internal combustion engine, especially for a motorcycle, comprising at least one first injection device (9), running directly into a combustion chamber (6) of at least one cylinder (7) for the purpose of direct fuel injection, and at least one second injection device (10), running into the inlet flow path (1) of the cylinder (7) for the purpose of indirect fuel injection, at least one throttle valve (11, 11a) being arranged in the inlet flow path (1). Said throttle valve (11, 11a) is arranged downstream of the second injection device (10), thereby increasing combustion stability.

Description

Internal combustion engine

The invention relates to an internal combustion engine, in particular for a motorcycle, with at least one directly injecting into a combustion chamber of at least one cylinder first injector for direct fuel injection and at least one opening into an inlet flow path of the cylinder second injection device for indirect fuel injection, wherein at least one throttle valve is arranged in the inlet flow path , Furthermore, the invention relates to a method for operating an internal combustion engine, in particular for a motorcycle, with an automated transmission, wherein in the inlet flow two throttle valves are arranged one behind the other and wherein one of the two throttle valves is operated electronically by an electronic control unit and the other throttle manually by the driver ,

From DE 198 53 375 Al a reciprocating internal combustion engine with spark ignition is known, wherein an injection device opens directly into a cylinder and another injector in a suction pipe downstream of a throttle valve.

EP 1 555 403 A1 also discloses an internal combustion engine with direct and indirect injection, the injection jets of the injector injecting indirectly into the intake manifold being directed toward the mouths of the intake passage into the combustion chamber.

In known arrangements, the injector is arranged for indirect fuel injection downstream of the throttle. This requires the throttle to be located further away from the intake ports. This results in a larger volume between throttle and inlet channel. As a result, the residual gas content in the cylinder increases at the partial load. The combustion stability decreases.

It is known, in addition to a first, manually operable throttle insert a second throttle, which is controlled by a map. The second throttle is used to release a smaller intake area during acceleration and at low loads than is mechanically predetermined by the driver at the first throttle. The aim is to achieve improved drivability. An internal combustion engine with a manually operated throttle valve and an electronically operable throttle valve is known for example from US 5,575,255 A. The object of the invention is to avoid these disadvantages and to increase the combustion stability. A further object of the invention is to simplify the switching process in an internal combustion engine with an automated transmission.

According to the invention this is achieved in that the throttle valve is arranged downstream of the second injection device. Preferably, the inlet flow path comprises an intake funnel, the second injection device being arranged upstream of the intake funnel and injecting fuel into the intake funnel. This allows the throttle to be positioned closer to the intake ports. The volume after the throttle valve and thus the residual gas content at the partial load decrease.

It is particularly advantageous if the throttle flap is positioned directly at the beginning of the inlet channel arranged in the cylinder head.

Due to the close position of the throttle valve in the intake valves, the residual content in the cylinder decreases via pressure recovery at low loads. The combustion stability increases. As a result of the fact that the second injection device is arranged upstream of the intake funnel, that is to say relatively far away from the intake valves, the intake air is cooled by means of evaporation heat during the indirect fuel injection. This has an advantageous effect on the degree of delivery and engine performance.

It is particularly advantageous if the initial cross section of the inlet ducts approximately corresponds to the cross section of the throttle valve. This allows the throttle to be positioned closer to the intake valves.

The throttle valve can also be arranged directly in the cylinder head.

In a further embodiment of the invention it is provided that upstream of a first throttle valve, a second throttle valve is arranged, which serves the better load control and the improvement of the acoustics. With the help of this second throttle, at least partial decoupling of the load control by the driver (throttle position) can take place.

The injection jet of the second injector is preferably oriented so that no liquid fuel contacts the suction tube walls, but the entire intake air flow is detected. This ensures maximum cooling of the air and the best possible evaporation.

The second injector serves to cool the fuel at full load and to cover large quantities of fuel at high speeds when the injection duration for the direct injection is too short. The second injector is activated only from a certain load and a certain speed.

The first injection device covers the additional fuel requirement under transient load conditions (acceleration enrichment). The second injector is used to cover the stationary demand for fuel needed to achieve maximum torque and maximum power. This ensures a very fast response of the internal combustion engine.

The second injector injects between 0% and a maximum of 50% of the injection quantity. It is injected via the second injector only the amount that can contribute to increasing the power density increase of the intake air through evaporative cooling.

A simplification of the switching process is achieved in that by means of the electronically operated throttle valve during a gear change operation or a starting operation, a predetermined by the electronic control unit torque reduction is performed with unchanged manual throttle. Preferably, it is provided that when performing an automated gear change operation, at least one clutch in the drive train depending on the driving condition, the vehicle speed and the throttle position is separated and is initiated by the electronically actuated throttle reduction of the engine torque at unchanged open mechanical throttle.

Upon reaching a driving state in which the transmission control unit detects the necessity of a speed change, an automatic speed change operation is performed by the transmission control unit. For this purpose, depending on the driving condition, the vehicle speed and the throttle position before the switching operation, the clutch is opened by an automated clutch actuation. During or after completion of the clutch opening process, a reduction of the engine torque is initiated by the additional electronic throttle with an open, mechanical throttle to prevent run-up of the engine due to the separation from the drive. During the subsequent gear change operation, the engine speed may be controlled to a predetermined value, given the necessary functionality in the transmission or engine control unit.

Preferably, the engine speed is controlled before or after completion of the gear change operation to a suitable value for the target gear. Preferably, during or after completion of the clutch closing operation, the engine torque is adjusted to the demand torque by the electronically controlled throttle adjusted or increased according to a predetermined ramp until the torque required by the driver through the mechanical throttle valve is exceeded and thus the torque and engine control is again by the driver. Upon completion of a shift, the electronic throttle may be fully opened to minimize intake losses. Depending on the functionality of a tracking of the mechanical throttle valve can be done to reduce a response time at an initiation of a switching operation.

In addition to the gear change operation, the additional electronic throttle may be used to start-up to adjust the torque delivered by the engine to the required torque while the mechanical throttle position is unchanged while the clutch is engaged.

Furthermore, by means of the additional electronic throttle valve, an intervention in the engine control takes place in order to avoid safety-critical driving conditions with unchanged mechanical throttle position.

The invention will be explained in more detail below with reference to FIG. Show it :

1 shows an inlet flow path of an internal combustion engine according to the invention in a longitudinal section in a first embodiment,

2 shows an inlet flow path of an internal combustion engine according to the invention in a longitudinal section in a second embodiment variant,

3 shows an inlet flow path of an internal combustion engine according to the invention in a longitudinal section in a further embodiment variant, and

Fig. 4 different engine parameters during a switching operation.

The figures each show an inlet flow path 1 of an internal combustion engine in a longitudinal section. The intake flow path 1 has an intake funnel 2 and an intake passage 4 arranged in the cylinder head 3. The inlet channel 4 opens into the combustion chamber 6 of a cylinder 7 via an inlet opening 5, which is controlled by an inlet valve (not further shown). Reference numeral 8 denotes a spark plug opening into the combustion chamber 6.

For fuel injection, a first injection device 9 opening directly into the combustion chamber 6 and a second injection device 10 are provided. The second injection device 10 is upstream of a in the inlet flow mung 1 arranged throttle valve 11 and positioned upstream of the suction hopper 2, wherein the second injector 10 is directed into the intake hopper 2. The second injection device can be designed as a multipoint injector.

It is essential that the throttle valve 11 is positioned as close as possible to the intake valves. In the exemplary embodiment, the throttle valve 11 is arranged directly at the beginning of the inlet channel 4 formed by the cylinder head 3, whereby the residual gas content in the cylinder 7 can be lowered in the low part load range and thus the combustion stability can be increased. The second injection device 10 in front of the intake funnel 2 serves above all to cover the full load power with the throttle valve 11 open. The air sucked in is cooled by the fuel injected via the second injection device 10 into the intake funnel 2. By the second injector 10 further, the injection duration of the injecting directly into the combustion chamber 6 first injector 9 can be kept as short as possible at high speeds. Due to the long travel distance of the fuel injected via the second injection device 10 into the intake funnel 2 up to the intake valves, the intake air is cooled particularly well. This has a particularly advantageous effect on the degree of delivery and the performance of the internal combustion engine.

The initial cross section of the intake passage 4 approximately corresponds to the cross section of the throttle valve 11. As a result, the throttle valve 11 can be positioned closer to the intake valves.

The throttle valve 11 can also be arranged directly in the cylinder head.

As shown in FIG. 2, upstream of the throttle valve 11, another throttle valve 11a may be arranged to serve the better load control and the improvement of the acoustics. With the help of this throttle valve IIa, at least partial decoupling of the load control by the driver (throttle position) can take place.

The injection jet of the second injector 10 is aligned so that no liquid fuel contacts the suction tube walls 12a of the suction tube 12, but the entire sucked air flow is detected. This ensures maximum cooling of the air and the best possible evaporation.

The second injector 10 is used for fuel cooling at full load and for covering large amounts of fuel at high speeds when the duration of injection for the direct injection is too short. The second injector 10 is activated only from a certain load and a certain speed. The first injector 9 covers the additional fuel requirement in transient load conditions (acceleration enrichment). The second injector 10 is used to cover the steady need of fuel needed to achieve maximum torque and maximum power. This ensures a very fast response of the internal combustion engine.

The second injection device 10 injects between 0% and a maximum of 50% of the total injection quantity. It is injected via the second injector 10, only the amount that can contribute to increasing the power density increase of the sucked air by evaporative cooling.

3 shows an intake flow path 101 of an internal combustion engine in a longitudinal section. The intake flow path 101 includes an intake funnel 102 and an intake passage 104 disposed in the cylinder head 103. The inlet channel 104 opens into the combustion chamber 106 of a cylinder 107 via an inlet opening 105, which is controlled by an inlet valve (not further shown). Reference numeral 108 denotes a spark plug opening into the combustion chamber 106.

In the intake flow path 104, there is disposed a first throttle 111 manually operated by the throttle by the driver, and an electronically operable second throttle lilac, which is operated by an electronic control unit such as a transmission control unit, upstream thereof. The second throttle valve is closed during the switching operation by the electronic control unit. Furthermore, there is an intervention in the ignition and the injection of the internal combustion engine. This allows a fully automatic upshift, without requiring the operator to operate the throttle lever, the connection between the throttle lever and throttle valve in a conventional manner via cable, so not electrically via cable occurs.

Due to the additional electronically actuated second throttle valve purple, a predetermined by the transmission or engine control unit torque reduction can be made with open mechanically actuated first throttle valve 111 to perform an automatic switching operation or a starting process.

If the transmission control unit detects the necessity of a gear change, the transmission control unit initiates an automated gear change operation. For this purpose, depending on the driving condition, the vehicle speed and the throttle position before the switching operation, the clutch is opened by an automated clutch actuation. While or after the completion of the clutch opening operation, a reduction of the engine torque is initiated by the additional electronic second throttle valve lila with an open mechanical first throttle valve 111 remains unchanged in order to prevent the engine from starting up due to the separation from the output. During the subsequent gear change process, the engine speed can be regulated to a predetermined value. In this case, the engine speed can be adjusted before or after completion of the gear change process to a suitable value for the target gear. During or after completion of the closing process of the clutch, the engine torque is adjusted by the electronically controlled second throttle li la to the required torque or increased by a predetermined ramp until the torque required by the driver through the mechanical throttle valve is exceeded and thus the torque and engine control again happens by the driver.

After completion of a shift operation, the electronic second throttle valve can remain completely open in order to keep the intake losses low.

Alternatively or additionally, a tracking of the mechanical first throttle valve 111 can be performed in order to reduce the response time at an initiation of a switching operation.

Furthermore, the additional electronic second throttle li la can also be used to start to adjust during the engagement process delivered by the engine torque, with unchanged mechanical throttle position, to the required.

In Fig. 4, the clutch position C, the throttle position T and the gear position G during a gear change operation over the time t is shown. It can be seen that the second throttle valve purple is already closed after the beginning of the opening of the clutch disconnection process and is only opened again after the gear change is completed, while the first throttle valve 111 remains in its unchanged position.

Claims

1. internal combustion engine, in particular for a motorcycle, with at least one directly into a combustion chamber (6) at least one cylinder (7) opening first injector (9) for direct fuel injection and at least one in an inlet flow path (1) of the cylinder (7) opening second Injection device (10) for indirect fuel injection, wherein in the inlet flow path (1) at least one throttle valve (11, IIa) is arranged, characterized in that at least one throttle valve (11, IIa) is arranged downstream of the second injection device (10).

2. Internal combustion engine according to claim 1, characterized in that the inlet flow path (l) has an intake funnel (2) and that the second injection device (10) is arranged upstream of the intake funnel (2) and injects fuel into the intake funnel (2).

3. Internal combustion engine according to claim 1 or 2, characterized in that at least one throttle valve (11, IIa) is positioned directly at the beginning of the cylinder head (3) arranged inlet channel (4).

4. Internal combustion engine according to one of claims 1 to 3, characterized in that at least one throttle valve (11, IIa) in the cylinder head (3) is arranged.

5. Internal combustion engine according to claim 3 or 4, characterized in that the initial cross section of the inlet channel (4) corresponds to the cross section of the throttle valve (11, IIa).

6. Internal combustion engine according to one of claims 1 to 5, characterized in that upstream of a first throttle valve (11), a second throttle valve (IIa) is arranged, wherein the second throttle valve (I Ia) preferably downstream of the second injection device (10) is arranged.

7. Internal combustion engine according to one of claims 1 to 6, characterized in that the injection cone of the second injection device (10) is aligned so that the entire air flow in the suction pipe (12) is detected.

8. Internal combustion engine according to one of claims 1 to 7, characterized in that the injection cone of the second injection device (10) so is aligned so that no liquid fuel touches the Saugrohrwände (12a).

9. Internal combustion engine according to one of claims 1 to 8, characterized in that the second injection device (10) is activated only from a limit speed and / or a limit load.

10. Internal combustion engine according to one of claims 1 to 9, characterized in that the transient load requirements can be covered by the first injection device (9).

11. Internal combustion engine according to one of claims 1 to 10, characterized in that the second injection device (10) only a maximum of 50%, preferably injects a maximum of 30% of the stationary fuel demand.

12. A method for operating an internal combustion engine, in particular for a motorcycle, with an automated transmission, wherein in the inlet flow path (101) two throttle valves (111, purple) are arranged one behind the other and wherein one of the two throttle valves (purple) electronically by an electronic control unit and the other throttle valve (111) is manually operable by the driver, characterized in that by means of the electronically operated throttle valve (purple) in a gear change operation or a starting operation by the electronic control unit predetermined torque reduction with unchanged manual throttle (111) is performed.

13. The method according to claim 12, characterized in that when performing an automated gear change operation, at least one clutch in the drive train depending on the driving condition, the vehicle speed and the throttle position is separated and is initiated by the electronically actuated throttle reduction of the engine torque at unchanged open mechanical throttle ,

14. The method according to claim 12 or 13, characterized in that during the following gear change operation, the engine speed is controlled by the electronic control unit to a predetermined value.

15. The method according to any one of claims 12 to 14, characterized in that the engine speed is regulated before or after completion of the gear change operation to a suitable value for the target gear.

16. The method according to any one of claims 12 to 15, characterized in that during or after completion of the clutch closing operation, the engine torque is adjusted by the electronically controlled throttle (purple) to the required torque or increased by a predetermined ramp until the driver by the mechanical Throttle (111) required torque is reached or exceeded.

17. The method according to any one of claims 12 to 16, characterized in that after completion of the switching operation, the electronically operable throttle (purple) is completely opened.

18. The method according to any one of claims 12 to 17, characterized in that after completion of the switching operation, the electronically operable throttle (purple) of the mechanically actuable throttle valve (111) is tracked.

19. The method according to any one of claims 12 to 18, characterized in that during a coupling process, the torque delivered by the engine by operating the electronic throttle (purple) - is adjusted to the required torque - with unchanged mechanical throttle position (111).

20. The method according to any one of claims 12 to 19, characterized in that by means of the electronically actuable throttle at least one intervention in the engine control is performed to avoid safety-critical driving conditions with unchanged mechanical throttle position.