Control method and system for fuel injector

A control method for a vehicle injector includes an injection time determination step in which a controller determines whether it is necessary for multiple injectors to inject fuel according to a combustion cycle of a combustion chamber, an individual injection step in which the controller controls each of the multiple injectors to individually inject fuel at different times when the controller determines in the injection time determination step that it is necessary for the injectors to inject fuel, and a simultaneous injection step in which the controller controls each of the multiple injectors to simultaneously inject fuel after the multiple injectors individually inject fuel at different times in the individual injection step.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims the benefit of priority to Korean Patent Application No. 10-2015-0177237, filed on Dec. 11, 2015 with the Korean Intellectual Property Office, the entire content of which is incorporated herein for all purposes by this reference.

TECHNICAL FIELD

The present disclosure relates to a control method and system for a fuel injector that supplies fuel to a vehicle engine. More particularly, the present disclosure relates to a control method and system for a fuel injector, which may effectively improve combustion efficiency and reduce harmful exhaust gasses, through an injection plan using multiple injectors.

BACKGROUND

Various techniques pertaining to a fuel injection method, an intake control method and a structure of an intake port have been developed and have been applied to a vehicle in order to improve engine efficiency.

Among the various techniques, as a method for improving efficiency of a vehicle engine, a method in which fuel ingredients have a constant concentration in a mixer by improving the performance of mixing air and fuel that flow into a combustion chamber has been developed, and the combustion efficiency of an engine may be increased by quickening an ignition time.

Particularly, in order to improve the performance of mixing air and fuel, an injection variable such as the injection time or pattern of an injector may be controlled to induce swirling, whereby ignition is stimulated and combustion efficiency may be improved.

Here, swirling indicates that intake air flowing in a combustion chamber forms eddies that rotate along a circumference of a combustion chamber. Due to the swirling intake air, the performance of mixing the intake air and fuel in the combustion chamber is improved and combustion efficiency may be improved.

Also, when fuel is injected by the injection nozzle of an injector arranged in an intake port side, if the fuel injected by the injector adheres to the flow path of the intake port, this may adversely affect the fuel efficiency of an engine. Therefore, the prevention of the adhesion of fuel is important in improving the efficiency of an engine.

SUMMARY

The present disclosure relates to a control method and system for a vehicle injector, and an object of the present disclosure is to effectively improve combustion efficiency and to reduce harmful substances of exhaust gas through an injection plan using multiple injectors.

In order to achieve the above object, a control method for a vehicle injector according to the present disclosure may include: an injection time determination step in which a controller determines whether it is necessary for multiple injectors to inject fuel according to a combustion cycle of a combustion chamber; an individual injection step in which the controller controls each of the multiple injectors to individually inject fuel at different times when the controller determines in the injection time determination step that it is necessary for the injectors to inject fuel; and a simultaneous injection step in which the controller controls each of the injectors to simultaneously inject fuel after the injectors individually inject fuel at different times in the individual injection step.

In the individual injection step, the controller may control each of the injectors to make the injectors alternately inject fuel multiple times.

In the individual injection step, the controller may control a fuel injection section of each of the injectors to form a delay section, during which fuel injection is not performed, in an interval between the fuel injection sections of the injectors.

In the simultaneous injection step, the controller may regulate a total fuel amount injected in one combustion cycle by regulating an amount of fuel injected by each of the injectors.

In the individual injection step, the multiple injectors may be arranged on an intake port of an engine, and the controller may make the multiple injectors perform a first fuel injection in a state in which an intake valve arranged in the combustion chamber is closed.

Meanwhile, in order to achieve the above object, a control system for a vehicle injector according to the present disclosure may include: injectors arranged to inject fuel toward a combustion chamber of an engine; and a controller for determining whether it is necessary for the injectors to inject fuel according to a combustion cycle of a combustion chamber, for controlling each of the injectors to make the injectors individually inject fuel at different times when determining that it is necessary for the injectors to inject fuel, and for controlling each of the injectors to make the injectors simultaneously inject fuel after the injectors individually inject fuel at different times.

DETAILED DESCRIPTION

Hereinbelow, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

As illustrated inFIGS. 1, 2 and 4, a control method for a fuel injector according to embodiments of the present disclosure may include: an injection time determination step (S100) in which a controller40may determine if it is necessary for multiple injectors20to inject fuel according to a combustion cycle in a combustion chamber10; an individual injection step (S200) in which the controller40may control each of the injectors20to make the injectors individually inject fuel at different times when determining in the injection time determination step (S100) that the fuel injection by the injectors20is required; and a simultaneous injection step (S300) in which the controller40may control the injectors to make the injectors simultaneously inject fuel after the injectors20inject fuel at different times in the individual injection step (S200).

Specifically, in the injection time determination step (S100), the controller40may determine if it is necessary for the multiple injectors20to inject fuel according to the combustion cycle of the combustion chamber10.

In the present disclosure, the controller40may be an ECU for controlling an engine, but an additional controller40for the injectors20may be arranged separately. In this case, the controller40may determine the fuel injection time by observing an engine operation condition, specifically, the combustion cycle of the combustion chamber10in which the injectors20are located. The exact time for fuel injection may be controlled depending on a driving condition of a vehicle.

Meanwhile, when the controller40determines in the injection time determination step (S100) that it is necessary for the injectors20to inject fuel, the controller40may control each of the injectors20to make the multiple injectors individually inject fuel at different times in the individual injection step (S200).

Accordingly, the fuel injection sections during which the respective injectors inject the fuel may not overlap each other.

In a state in which multiple injectors20are arranged in a single combustion chamber10, if the controller40makes the multiple injectors20inject fuel at different times rather than making them simultaneously inject fuel, the flow of the fuel injected by each of the injectors20may not have symmetry. Accordingly, a flow deviating from the center of the combustion chamber10, which may be a flow that rotates along the side of the combustion chamber10, may be made.

Such a fuel flow may occur more easily when the multiple injectors20are arranged on an intake port30and each of the injectors20injects fuel towards the side of the combustion chamber10rather than towards the center point of the combustion chamber10.

FIG. 4illustrates an example in which two intake valves may be located in a single combustion chamber10, injectors20may be arranged on an intake port30of each of the intake valves, and each of the injectors20may be arranged to inject fuel towards the point deviated from the center of the combustion chamber10.

In other words, when only one injector20injects fuel, the fuel flows along the side of the combustion chamber10and swirling may be easily induced because the fuel flow may not be disturbed by the flow of fuel injected by another injector20.

Here, swirling indicates that intake air flowing into the combustion chamber10may form eddies that rotate along the circumference of the combustion chamber10. Due to the swirling intake air, the performance in, or of, mixing the intake air and fuel in the combustion chamber10is improved, thus increasing combustion efficiency.

Consequently, as the multiple injectors20may inject fuel at different times, the flow of fuel injected by each of the injectors20may rotate along the wall of the combustion chamber10and swirl. As the swirling occurs, the performance in, or of, mixing air and fuel is improved and fuel efficiency is improved.

Also, an ignition time may be regulated. For example, an ignition time may be quickened by adjusting the injection pattern or injection time of each of the injectors20. Accordingly, the combustion section, in which combustion is performed in the combustion chamber10, may be timely controlled in order to satisfy the power performance required for each driving section. InFIG. 2, the individual injection120may be depicted as a section in which the controller40makes a pair of injectors20inject fuel at different times.

Meanwhile, after the multiple injectors20inject fuel at different times in the individual injection step (S200), the controller40may control each of the injectors20to make the multiple injectors inject fuel together in the simultaneous injection step (S300).

In the simultaneous injection step of the present disclosure, as the injectors may inject the fuel together, the fuel injection sections during which the respective injectors inject the fuel may overlap with each other. The injectors may simultaneously inject the fuel. However, even if the injectors inject the fuel at exactly the same time, when the fuel injection sections overlap each other by a degree of 70% or greater, such overlapping timing may have the effect of simultaneous fuel injection described by the present disclosure.

During the individual injection120in which each of the injectors20may inject fuel for a relatively short time, it may be difficult to regulate the amount of fuel to be injected. In particular, in consideration of a fuel pressure and design of the injectors20, it may be difficult to satisfy more than a certain level of a fuel amount only through the individual injection120.

Also, in the individual injection120in which initial fuel injection may be performed when the intake valve of the combustion chamber10is open, if the fuel amount increases, the fuel may unnecessarily adhere to the intake valve or the wall of the intake port30, thus reducing the fuel efficiency and/or increasing exhaust gasses.

Therefore, the controller40may make the injector20inject fuel through multiple phases to reduce the amount of fuel injected at a single phase, whereby the fuel may be prevented from adhering to the intake port30. Also, because the simultaneous injection step (S300) may be performed after the individual injection phase (S200), the fuel amount required for each driving section may be satisfied.

Furthermore, after swirling is induced in the individual injection step, the swirl of the fuel flow in the combustion chamber may be disrupted in the simultaneous injection step, and this may be advantageous in improving the performance in mixing the intake air and fuel.FIG. 2shows a simultaneous injection220after the individual injection120of the injectors20.

Meanwhile, as illustrated inFIG. 2, in a control method for a fuel injector according to an embodiment of the present disclosure, the controller40may make the injectors20alternately perform multiple times of fuel injection in the individual injection step (S200).

As described above, the controller40may control each of the injectors20to make the injectors20individually inject fuel at different times. Specifically, the controller40may make the injectors20alternately perform fuel injection multiple times so as to induce a swirling effect.

When the multiple injectors20alternately induce swirling in the combustion chamber10, the fuel flows may be mutually disturbed by each other. Accordingly, the performance in mixing air and fuel in the combustion chamber10may be improved compared to the case in which swirling is induced by the fuel injected by an injector20arranged in one side.FIG. 2shows an example in which a fuel injection section is set in such a way that a pair of injectors20alternately inject fuel.

Meanwhile, as illustrated inFIGS. 2 and 3, in a control method for a fuel injector according to an embodiment of the present disclosure, the controller40may control the fuel injection sections of the injectors20to form a delay section250, during which fuel injection may not be performed, in the interval between the fuel injection sections of the injectors20in the individual injection step (S200).

Specifically, the flow of the fuel injected by each of the injectors20may induce swirling in the combustion chamber10in the individual injection step (S200). However, if an injector20in, or disposed in, one side and an additional injector in, or disposed in, another side consecutively inject fuel, the flow of fuel injected by the injector in the one side may be disturbed by the flow of the fuel injected by the additional injector20in the other side, before swirling is induced in the combustion chamber10.

Therefore, in order to ensure a sufficient time to induce swirling in the flow of fuel injected by an injector arranged in one side and to sufficiently mix the fuel and air, a delay section250may be formed in the interval between the fuel injection sections of the injectors20.FIG. 3shows an example in which a delay section250may be set in the interval between the fuel injection sections of the injectors20.

Consequently, the controller40may control the injectors20to make a delay section250in the interval between the fuel injection sections of the injectors20, whereby a sufficient time may be secured to enable the flow of fuel injected by each of the injectors20to swirl, thus improving the performance in, or of, mixing the fuel and air.

Meanwhile, in a control method for a fuel injector according to an embodiment of the present disclosure, the controller40may regulate the total amount of fuel in one combustion cycle by regulating an amount of fuel simultaneously injected by each of the injectors20in the simultaneous injection step (S300).

As described above, in the present disclosure, the amount of fuel injected by the injectors20may be regulated in the simultaneous injection step (S300), whereby fuel may be prevented from adhering to the wall of the intake port30in the individual injection step (S200) and the fuel amount required for each driving section may be satisfied in order to prevent the combustion efficiency of an engine from decreasing.

Meanwhile, in a control method for a fuel injector according to an embodiment of the present disclosure, the multiple injectors20may be arranged on the intake port30of the engine, and the controller40may control the multiple injectors20to perform first fuel injection in a state in which the intake valve arranged in the combustion chamber10is closed, in the individual injection step (S200).

In the engine, when the intake valve in the combustion chamber10opens, intake air may flow into the combustion chamber10. Then, in a state in which the intake valve is closed, the intake air may be compressed and exploded, and an exhaust stroke may be performed. When multiple injectors20are arranged on the intake port30of the engine, the fuel injected by the injectors20may flow into the combustion chamber10only if the intake valve is open.

Accordingly, if the injectors20arranged on the intake port30inject fuel in a state in which the intake valve is open, the fuel may flow into the combustion chamber10and mix with air in the combustion chamber10. Conversely, if the injectors20perform the first fuel injection shortly before the intake valve opens, namely in a state in which the intake valve is closed, the fuel that has been mixed with air in the intake port30may flow into the combustion chamber10when the intake valve opens.

In other words, in an embodiment of the present disclosure, according to fuel injection through the multiple phases, the first fuel injection may be performed in a state in which the intake valve is closed, whereby a time for mixing the fuel and air may be secured before the intake stroke, and the performance in mixing the fuel and air is improved.

Meanwhile, as illustrated inFIG. 4, a control system for a vehicle injector according to an embodiment of the present disclosure may include: injectors20arranged to inject fuel into the combustion chamber10of an engine; and a controller40arranged to determine whether it is necessary for the injectors20to inject fuel according to the combustion cycle of the combustion chamber10, to control each of the injectors20to make the injectors20inject fuel at different times when determining that fuel injection is necessary, and to control each of the injectors20to make the injectors20simultaneously inject fuel after the injectors20inject fuel at different times.

Specifically, each of the injectors20may have an injection nozzle that faces the combustion chamber10so as to inject fuel into the combustion chamber10. Each of the injectors20may have an injection nozzle arranged in the combustion chamber10, and the injection nozzle may be arranged on the intake port30so as to inject fuel towards the intake valve.

Meanwhile, the controller40may determine whether it is necessary for the injectors20to inject fuel according to a combustion cycle of the combustion chamber10, may control each of the injectors20to make the injectors20individually inject fuel at different times when determining that the fuel injection is required, and may control each of the injectors20to make the injectors20simultaneously inject fuel after the injectors20inject fuel at different times.

As described above, the controller40may be an ECU corresponding to an engine controller40or a controller40separately arranged for controlling the injectors20. The controller40may determine whether it is necessary for the injectors20to inject fuel by observing an operation condition of the combustion chamber10. Also, when the fuel injection is required, the controller40may control the multiple injectors20to inject fuel at different times so that the injected fuel swirls in order to improve the performance in, or of, mixing the fuel and air.

Meanwhile, after the multiple injectors20inject fuel at different times, the controller40may make the multiple injectors20simultaneously inject fuel, whereby the excessive amount of fuel may be prevented from being injected when the injectors20individually inject fuel, and thus the fuel may be prevented from adhering to the intake port30. Also, because the fuel amount required for one combustion cycle can be regulated by the simultaneous fuel injection, the fuel amount required for each driving section may be satisfied.

According to the above-described control method and system for a vehicle injector, through an injection plan using multiple injectors, combustion efficiency may be improved, and exhaust gases may be reduced.

Particularly, because swirling is induced in a combustion chamber through an individual injection plan in which multiple injectors inject fuel at different times, performance in mixing the fuel and intake air may be improved and ignition may be stimulated, thus improving a combustion condition and maximizing fuel efficiency.

Also, even if the amount of fuel injected by the individual injection plan is constant, the fuel amount required by each combustion cycle depending on the driving condition may be regulated through a simultaneous injection plan in which multiple injectors simultaneously inject fuel after the individual injection plan. Therefore, fuel efficiency may be improved and adhesion of fuel to various surfaces may be prevented.

Meanwhile, as a delay time during which fuel injection is interrupted may be formed in an interval between injection sections of injectors, swirling may be stably induced in a combustion chamber through the individual injection plan, thus maximizing performance in mixing fuel and air.