WO2018059705A1

WO2018059705A1 - Method for changing a distribution between port fuel injection and direct injection in an internal combustion engine

Info

Publication number: WO2018059705A1
Application number: PCT/EP2016/073392
Authority: WO
Inventors: Anja Blau; Oliver Abendroth; Rene Passon
Original assignee: Robert Bosch Gmbh
Priority date: 2016-09-30
Filing date: 2016-09-30
Publication date: 2018-04-05
Also published as: CN109790787A; KR20190053868A; JP2019533111A

Abstract

The invention relates to a method for changing a distribution between port fuel injection and direct injection, in an internal combustion engine (100) having port fuel injection and direct injection as injection types, from a first to a second distribution factor, wherein fuel quantities to be introduced into each combustion chamber (103) of the internal combustion chamber (100) according to the second distribution factor (A') are determined by means of the respective injection type. A firing angle (Δφ) is determined for each combustion chamber (103) while taking into account at least one torque requirement of the internal combustion engine (100), and the determined fuel quantities and the determined firing angle (Δφ) are adjusted.

Description

description

title

A method of changing a split to manifold injection and direct injection in an internal combustion engine

The present invention relates to a method for changing a split to port injection and direct injection in an internal combustion engine with these two types of injection and a computing unit and a computer program for its implementation.

State of the art

One possible method of fuel injection in gasoline engines is the intake manifold injection, which is increasingly being replaced by direct fuel injection. The latter method leads to significantly better fuel distribution in the combustion chambers and thus to better power output with lower fuel consumption.

Furthermore, there are also gasoline engines with a combination of intake manifold injection and direct injection, a so-called dual system. This is particularly advantageous in the light of ever stricter emission requirements or emission limit values, since the intake manifold injection, for example, results in better emission values at medium load ranges than direct injection.

Due to the different power output in the different types of injection, however, a change in the distribution of the two types of injection may now result in a change in the torque output by the internal combustion engine, which may be, for example, jerking for a driver due to a power dip or an increase in power can make noticeable. Disclosure of the invention

According to the invention, a method for changing a distribution to Saugrahreinspritzung and direct injection in an internal combustion engine and a

Arithmetic unit and a computer program for its implementation with the features of the independent claims proposed. Advantageous embodiments are the subject of the dependent claims and the following description.

Advantages of the invention

An inventive method is used to change a split on intake manifold injection and direct injection in an internal combustion engine with Saugrahreinspritzung and direct injection injection types from a first to a second division factor. For this purpose, fuel quantities to be introduced in accordance with the second distribution factor are determined by means of the respective injection type in each combustion chamber of the internal combustion engine. Furthermore, in each case an ignition angle is determined for each combustion chamber taking into account at least one torque request to the internal combustion engine and the determined fuel quantities and the determined ignition angles are set.

By adjusting the ignition angle with a change in the distribution to the two types of injection, the torque which adjusts itself after the change can now be deliberately acted upon and, if necessary, influenced by this adaptation of the

Zündwinkels be changed. This is possible since a change in the ignition angle causes a change in the torque generated in the respective combustion chamber. Thus, for example, in total, ie seen over both types of injection, the same amount of fuel before and after the change of the division can be achieved that the torque output by the engine does not change or only insignificantly. Without this adjustment of the ignition angle would result in a noticeable other torque due to the different power output in the two injection types in the rule. Without adjusting the ignition angle at the same time as changing the An adaptation of the torque to a desired value could take place later. A driver of an associated motor vehicle thus does not feel any effects on the ride comfort at various operating points in the proposed method. At the same time, however, for example, an improvement in the emission and consumption values of the internal combustion engine can be achieved by changing the distribution.

Preferably, the determination of the fuel quantities and / or the ignition angle for each combustion chamber is done individually. In this way, the operation of the internal combustion engine which is as uniform as possible can be achieved, since the combustion chamber-specific torques correspond to the required torque due to the combustion chamber-individual ignition angle adaptation.

Advantageously, as the at least one torque request to the internal combustion engine, a torque request is used before and / or after the change in the distribution. In this way it can be achieved that as far as possible the desired torque is delivered by the internal combustion engine. Expediently, the torque requirements before and after the change of the distribution deviate from one another by at most 5%, in particular by at most 2%. It is particularly preferred if no deviation occurs between the torque requirements before and after the change in the distribution. In other words, a constant or at least almost constant operating point with respect to the torque request is realized in this way, despite a change in the allocation to the types of injection. For a driver, therefore, a change in distribution is not or at least almost unnoticeable despite, for example, the achieved emission value improvement.

It is advantageous if the ignition angles are interpolated taking into account the second distribution factor between corresponding ignition angles for a pure intake manifold injection and a pure direct injection. The ignition angles for the pure intake manifold injection and the pure direct injection can preferably be in a table or a map, in particular for ver¬ different torque requirements and / or fuel quantities, be deposited. It should be noted that the firing angle for the same torque requirement in the two types of injection are usually different. In which of the two types of injection the ignition angle is earlier, can depend on the type and geometry of the engine concerned. By a suitable interpolation can thus very easily a suitable ignition angle for a mixed operation, ie at the same time intake manifold and direct injection, determined and adjusted.

Preferably, as part of the determination of the amounts of fuel to be introduced by means of the respective type of injection into each combustion chamber of the internal combustion engine in accordance with the second distribution factor, an adjustment of the fuel quantities taking into account the at least one torque request to the internal combustion engine. In this way, any torque differences due to the change in the distribution of the types of injection and the concomitant change in the distribution of the respective fuel quantities for the respective types of injection also by Mehrbzw. Reduced quantities of fuel are taken into account. This allows an even better retention or maintenance of the desired torque.

Advantageously, an air charge for each combustion chamber is further determined and adjusted taking into account the at least one torque request to the internal combustion engine. This also allows even better maintenance or compliance with the desired torque, since the combustion and thus the torque output can be influenced by the amount of air supplied. In addition, the emission values can also be improved in this way.

An arithmetic unit according to the invention, e.g. a control unit, in particular an engine control unit, of a motor vehicle is, in particular programmatically, configured to perform a method according to the invention.

Also, the implementation of the method in the form of a computer program is advantageous because this causes very low costs, especially if a executive controller is still used for other tasks and therefore already exists. Suitable data carriers for the provision of the computer program are, in particular, magnetic, optical and electrical memories, such as hard disks, flash memories, EEPROMs, DVDs and the like. It is also possible to download a program via computer networks (Internet, intranet, etc.).

Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawings. The invention is illustrated schematically with reference to an embodiment in the drawing and will be described below with reference to the drawing.

Brief description of the drawings

Figures 1a and 1b schematically show two internal combustion engines, which can be used for a method according to the invention.

Figure 2 shows schematically a cylinder of an internal combustion engine, which can be used for a method according to the invention.

FIG. 3 shows a sequence of a method according to the invention in a preferred embodiment. Embodiment (s) of the invention

FIG. 1 a shows schematically and simplified an internal combustion engine 100, which can be used for a method according to the invention. By way of example, the internal combustion engine 100 has four combustion chambers 103 and a suction tube 106, which is connected to each of the combustion chambers 103.

In this case, the intake manifold 106 has, for each combustion chamber 103, a fuel injector 107 which is arranged in the respective section of the intake manifold just before the combustion chamber. The fuel injectors 107 thus serve a Saugrohreinsprit- Zung. Furthermore, each combustion chamber 103 has a fuel injector 11 for direct injection.

FIG. 1 b shows schematically and in simplified form another internal combustion engine 200 which can be used for a method according to the invention. By way of example, the internal combustion engine 100 has four combustion chambers 103 and a suction tube 206, which is connected to each of the combustion chambers 103.

The intake manifold 206 has a common fuel for all combustion chambers 103! Njektor 207, which is arranged in the intake manifold, for example, shortly after a throttle valve, not shown here. The first fuel! Njektor 207 thus serves a port injection. Furthermore, each combustion chamber 103 has a fuel injector 11 for direct injection.

Both shown internal combustion engines 100 and 200 thus have a so-called dual system, i. via intake manifold injection and direct injection. The difference is only in the type of intake manifold injection. While, for example, the intake manifold injection shown in FIG. 1a permits a fuel metering individually for each combustion chamber, as can be used, for example, for higher quality internal combustion engines, the intake manifold injection shown in FIG. 1b is simpler in design and control. The two internal combustion engines shown may in particular be gasoline engines.

In FIG. 2, a cylinder 102 of the internal combustion engine 100 is schematically and simplified, but shown in more detail than in FIG. 1a. The cylinder 102 has a combustion chamber 103 which is enlarged or reduced by movement of a piston 104. The position of the piston can be given, for example, in relation to the so-called top dead center (TDC) at which the piston has reached its highest point (in relation to the figure). The present internal combustion engine may in particular be a gasoline engine.

The cylinder 102 has an inlet valve 105 to admit air or a fuel-air mixture into the combustion chamber 103. The air is supplied via the suction pipe 106 as part of an air supply, at which the fuel injector 107 located. Sucked air is admitted via the inlet valve 105 into the combustion chamber 103 of the cylinder 102. A throttle flap 112 in the air supply system is used to set the required air mass flow into the cylinder 102. By means of an air mass meter 120, for example in the form of a hot film air mass meter, the amount of air to be introduced through the suction pipe 106 into the combustion chamber 103 can be determined.

The internal combustion engine can be operated in the course of a port injection. With the aid of the fuel injector 107, fuel is injected into the intake manifold 106 in the course of this intake manifold injection, so that there is an air intake.

Fuel mixture forms, which is introduced via the inlet valve 105 into the combustion chamber 103 of the cylinder 102.

The internal combustion engine can also be operated in the course of a direct injection. For this purpose, the fuel! The injector 11 1 attached to the cylinder 102 to inject fuel directly into the combustion chamber 103. In this direct injection, the air-fuel mixture required for combustion is formed directly in the combustion chamber 103 of the cylinder 102. The cylinder 102 is further provided with an ignition device 1 10 to the

Starting combustion in the combustion chamber 103 to generate a spark. The ignition angle, ie the angle of the crankshaft 130, at which the ignition of the mixture takes place in the combustion chamber, can be given, for example, with the angle Δφ shown. The value Δφ = 0 ° corresponds to the top dead center, the ignition angle can then, for example. After top dead center. It should be noted that in a four-stroke internal combustion engine, two top dead centers exist, with an ignition only in the vicinity of each second such top dead center (ZOT). Combustion exhaust gases are expelled from the cylinder 102 via an exhaust pipe 108 after combustion. The ejection is dependent on the opening of an exhaust valve 109, which is also disposed on the cylinder 102. Inlet and exhaust valves 105, 109 are opened and closed to perform a four-stroke operation of the engine 100 in a known manner. The internal combustion engine 100 may be operated by direct injection, with intake manifold injection or in a mixed operation. This allows the selection of the optimum operating mode for operating the internal combustion engine 100 depending on the current operating point. For example, the engine 100 may be operated in a port injection mode when operated at a low speed and a low load, and may be operated in a direct injection mode when operated at a high speed and a high load. Over a wide operating range, however, it makes sense to operate the internal combustion engine 100 in a mixed operation in which the amount of fuel to be supplied to the combustion chamber 103 is supplied proportionally by intake manifold injection and direct injection.

Furthermore, a computing unit designed as a control unit 1 15 for controlling the internal combustion engine 100 is provided. The control unit 15 can operate the internal combustion engine 100 in the direct injection, the intake manifold injection or the mixed operation. Furthermore, the control unit 1 15 can also detect values from the air mass meter 120.

The operation of the internal combustion engine 100 explained in more detail with reference to FIG. 2 can also be transferred to the internal combustion engine 200 according to FIG. 1 b, with the only difference that only one common fuel injector is provided for all combustion chambers or cylinders. In the case of intake manifold injection or in a mixed operation, therefore, the single fuel injector in the intake manifold is actuated.

FIG. 3 schematically shows a sequence of a method according to the invention in a preferred embodiment. In this case, a distribution to the injection port types intake manifold injection and direct injection is to be changed from a first distribution factor A to a second distribution factor A '.

When changing this division, furthermore, a torque request D before the change and a torque request D 'after the change should also be taken into account. In particular, these two torque ment requirements, ie D = D '. This means that the change in the division at a constant operating point with respect to the torque request or torque output should be made. This may be desirable, for example, so that a driver of an associated motor vehicle does not feel the change in the distribution or at least as little as possible.

The two distribution factors A and A 'correspond to respective amounts of fuel M _s and M _D or M' _s and M ' _D for the respective portions of the intake manifold or direct injection. In the simplest case, the respective total fuel quantities can remain the same before and after the change in the distribution, ie

M _s + M _D = M's + M ' _D. However, it is also conceivable, for example, for an additional adaptation of the fuel quantities M ' _s and M' _D after the change.

Furthermore, the torque requirements when changing the distribution must be considered. In a map, for example, for different torque requirements corresponding ignition angle for the pure intake manifold injection and pure direct injection can be deposited. Thus, for example, for the torque request D 'an ignition angle Acp _s for a pure intake manifold injection and a firing angle Δφ _{0 be} deposited for a pure direct injection.

From these two ignition angles, Acp _s and Δφ ₀ , the ignition angle Δφ to be set can now be determined as a function of the second distribution factor A '. The ignition angle Δφ can be determined, for example, within the framework of an interpolation, in particular a linear interpolation, between the two ignition angles Δφ _δ and Δφ ₀ . These ignition angles should be determined individually for each combustion chamber, as well as the respective fuel quantities. In particular, at the ignition angle is important to ensure that the ignition timing of the individual combustion chambers are offset due to the connection of the respective pistons to the crankshaft of the internal combustion engine against each other.

In the course of the change of the distribution on the two types of injection thus the new fuel quantities and the new ignition angle, which have been determined as explained above, can be adjusted. By considering the Zündwinkels can be achieved that the torque that is released after the change of the internal combustion engine, or at least barely changes compared to before the change. Depending on the situation, however, a targeted change in the torque can be achieved.

An implementation of this method in an engine control unit can be carried out in such a way that, for example, in a software used, a status variable is defined, which is a Umschaltewunsch, i. indicates a desired change in the distribution of the type of injection, or changes its value accordingly in such a changeover request. This status variable can then trigger both the determination of the new fuel quantities and the determination of the new ignition angle. This allows a particularly simple and fast implementation of the proposed method.

Claims

A method of changing intake manifold injection and direct injection ratio in an intake manifold injection direct injection engine (100, 200) as injection modes from a first (A) to a second (Α ') split factor,

wherein by means of the respective type of injection into each combustion chamber (103) of the internal combustion engine (100, 200) according to the second division factor (Α ') to be introduced fuel quantities (M' _s , M ' _D ) are determined, wherein in each case an ignition angle (Δφ) for each combustion chamber (103) is determined taking into account at least one torque request (D, D ') to the internal combustion engine (100, 200), and

wherein the determined fuel quantities (M ' _s , M' _D ) and the determined ignition angle (Δφ) are set.

The method of claim 1, wherein the determination of the fuel quantities (M ' _s , M'D) and / or the firing angle (Δφ) for each combustion chamber (103) takes place individually.

The method of claim 1 or 2, wherein as the at least one torque request to the internal combustion engine, a torque request before (D) and / or after (D ') of the change of the distribution is used.

A method according to claim 3, wherein the torque requirements before (D) and after (D ') the change of the division by at most 5%, in particular by at most 2%. differ from each other.

5. The method according to any one of the preceding claims, wherein the firing angle (Δφ) taking into account the second division factor (Α ') between corresponding ignition angles (Acp _s , Δφ ₀ ) are interpolated for a pure intake manifold injection and a pure direct injection.

6. The method of claim 5, wherein the firing angle (Acp _s , Δφ ₀ ) for the pure intake manifold injection and the pure direct injection are stored in a table or a map.

7. The method according to any one of the preceding claims, wherein in the context of determining the by means of the respective injection in each combustion chamber (103) of the internal combustion engine (100, 200) according to the second division factor (Α ') to be introduced fuel amounts (M' _s , M ' _D ) an adjustment of the fuel quantities (M ' _s , M' _D ) taking into account the at least one torque request (D, D ') to the internal combustion engine (100, 200) takes place.

8. The method according to any one of the preceding claims, further comprising an air charge for each combustion chamber (103) taking into account the at least one torque request (D, D ') to the internal combustion engine (100, 200) is determined and adjusted.

9. arithmetic unit (1 15), which is adapted to perform a method according to any one of the preceding claims.

10. A computer program that causes a computing unit (115) to perform a method according to one of claims 1 to 8, when it on the

Processing unit (1 15) is executed.

1 1. A machine-readable storage medium with a computer program stored thereon according to claim 10.