KR102728854B1 - Apparatus and method for controlling of vehicle engine - Google Patents

Abstract

The present invention relates to a technology capable of reducing the emission of nitrogen oxides generated by the combustion of fuel and air while improving engine output efficiency by directly supplying an additive at a temperature below a certain level into the combustion chamber of a vehicle engine.
The vehicle engine control device and method according to the present invention provide driving power to the vehicle by introducing air into the combustion chamber of the vehicle engine, setting it to a high temperature and high pressure state, injecting fuel and an additive into the combustion chamber and combusting the fuel, and is characterized by directly injecting the additive into the combustion chamber through an additive injector at a time point after combustion of the vehicle engine starts.
Therefore, according to the present invention, by lowering the temperature inside the combustion chamber in the combustion section of the vehicle engine, the amount of nitrogen oxides generated due to the combustion reaction between fuel and air can be reduced, while at the same time, the pressure inside the combustion chamber can be increased, thereby improving engine output.

Description

{Apparatus and method for controlling of vehicle engine}

The present invention relates to a technology capable of reducing the emission of nitrogen oxides generated by the combustion reaction of fuel and air while improving engine output efficiency by directly supplying an additive at a temperature below a certain level into the combustion chamber of a vehicle engine.

A vehicle engine, which is a piston-type internal combustion engine, is a device that uses the heat generated by the combustion of fuel and air in the combustion chamber to increase the pressure of the working fluid and convert this into power.

At this time, fuel is supplied into the intake port or cylinder of the vehicle engine through the injector, and air, which acts as an oxidizer and working fluid, is sucked or exhausted into the combustion chamber of the vehicle engine using the intake valve and exhaust valve.

In this case, the kinetic energy generated by the vehicle engine is equal to the closed curve area (the area of the space formed by Q _1-2 , Q _2-3 , Q _3-4 , and Q _4-1 ) on the PV (pressure-volume) diagram and the TS (temperature-entropy) diagram as shown in Fig. 1.

According to the PV diagram (A) and TS diagram (B) of Fig. 1, when fuel and air are injected into the combustion chamber through the intake valve and the volume (V: internal space of the combustion chamber) increases, the pressure (P) is maintained at P ₁ while only the volume (V) increases, and when the volume is decreased to V ₂ from a state of a constant volume (V ₁ ), the pressure inside the combustion chamber gradually increases to P ₂ . Afterwards, fuel is supplied to the combustion chamber at a constant pressure (P ₂ ) to initiate combustion. In the combustion section (Q _2-3 ), the volume is maintained at V ₂ while only the pressure increases to P ₃ . When the combustion reaction is completed, the volume increases to V ₁ while the pressure decreases to P ₂ . Afterwards, as the exhaust gas inside the combustion chamber is discharged through the exhaust valve, the pressure in the combustion chamber decreases to P ₁ .

Meanwhile, looking at the state of entropy (S) and temperature (T) of the vehicle engine, when the volume (V) is increased from V ₁ to V ₂ , the entropy (S) maintains the S ₁ state while only the temperature (T) increases to T ₂ , and during Q _2-3 where the combustion process takes place, the temperature rises to T ₃ and the entropy also increases to S _2. Afterwards, when the combustion reaction is completed and the volume increases to V ₁ , the pressure decreases to P ₂ and during this time, the temperature decreases to T ₄ while the entropy is maintained at S _2. Then, when the exhaust gas is discharged while the volume is in the V ₁ state, the pressure decreases to P ₁ , the temperature decreases to T ₁ , and the entropy also decreases to S ₁ .

This oxidation process inside the combustion chamber takes place over a short period of time, and in order to improve the output and efficiency of the vehicle engine, it is advantageous to increase the maximum pressure and temperature as much as possible through rapid combustion.

However, the high temperature and high pressure combustion environment inside the combustion chamber promotes the combination reaction of nitrogen and oxygen in the air, which causes a problem of increased nitrogen oxide emissions.

Accordingly, there is a method of lowering the peak pressure and temperature inside the combustion chamber to reduce the emission of nitrogen oxides in the combustion chamber, and a method of injecting exhaust gas into the combustion chamber through an EGR (exhaust gas recirculation) structure is currently being proposed and used. The EGR structure is configured to feed back a portion of the exhaust gas discharged through the exhaust port of the combustion chamber to the intake port of the combustion chamber and recirculate it into the combustion chamber together with the intake air.

However, since the EGR structure supplies exhaust gas to the combustion chamber together with intake air at the point where the combustion reaction takes place, the temperature inside the combustion chamber is lowered, which has the effect of reducing the generation of nitrogen oxides. However, there is a problem in that the time until the combustion reaction takes place is long, the amount of oxygen required is reduced, and the combustion rate is lowered, which reduces engine output and fuel efficiency.

1. Korean Publication Patent No. 10-2019-0042275 (Title: Engine and its control method). 2. Korean Publication Patent No. 10-2018-0110972 (Title: Engine System)

Accordingly, the present invention has been created in consideration of the above circumstances, and has a technical purpose of providing a vehicle engine control device and method thereof that can reduce the emission of nitrogen oxides generated by the combustion reaction of fuel and air while improving engine output efficiency by directly supplying an additive at a temperature below a certain level into the combustion chamber of a vehicle engine.

According to one aspect of the present invention for achieving the above object, a vehicle engine control device is provided, comprising: a fuel injector connected to a fuel supply unit in which fuel is stored and injects fuel into a vehicle engine; an additive injector connected to an additive supply unit in which an additive made of a gaseous or liquid substance that absorbs heat is stored and injects the additive into the vehicle engine; a vehicle engine that introduces air into a combustion chamber, injects fuel and additive into the combustion chamber at a high temperature and high pressure to combust the fuel and thereby provide driving force to the vehicle; and a vehicle engine that controls the supply of fuel and additive to the vehicle engine through the fuel injector and the additive injector, wherein the additive injector is arranged to directly inject the additive into the combustion chamber of the vehicle engine, and the ECU controls the injection of the additive into the combustion chamber through the additive injector at a time point after combustion of the vehicle engine starts.

In addition, according to another aspect of the present invention for achieving the above object, a vehicle engine control method for providing driving force to a vehicle by introducing air or a mixture of air and fuel into a combustion chamber of a vehicle engine from an ECU and injecting fuel into the combustion chamber at a high temperature and high pressure to combust the fuel, the vehicle characterized in that it comprises a first step of opening an intake valve connected to a combustion chamber in the ECU and closing an exhaust valve and moving a piston in a first direction to introduce air or a mixture of air and fuel into the combustion chamber through the intake valve, a second step of setting the combustion chamber to a high temperature and high pressure state by moving the piston in a second direction while the air or the mixture of air and fuel is introduced into the combustion chamber, the third step of causing a combustion reaction of fuel and air in the high temperature and high pressure combustion chamber, a fourth step of injecting an additive made of a gaseous or liquid substance that absorbs heat into the combustion chamber where the combustion reaction takes place, and a fifth step of discharging exhaust gas generated by the combustion reaction inside the combustion chamber to the outside through an exhaust valve or port connected to the combustion chamber by moving the piston in the first direction after the combustion reaction is completed. A method of controlling an engine is provided.

Here, the additive is characterized by being one of substances below a certain temperature, including exhaust gas, air, water vapor, and liquid water.

In addition, the ECU is characterized by controlling the injection of an additive during a period from the start of combustion to the maximum combustion pressure range of the vehicle engine.

In addition, the ECU is characterized by controlling the additive to be injected after a preset time has elapsed from the start of combustion.

According to the present invention, by a simple method of injecting a certain amount of additive into the combustion chamber after the combustion point in the combustion section of a vehicle engine, the temperature inside the combustion chamber is lowered, thereby reducing the amount of nitrogen oxides generated due to the combustion reaction between fuel and air, and at the same time increasing the pressure inside the combustion chamber, thereby improving engine output.

Figure 1 is a drawing to explain typical vehicle engine characteristics.
Figure 2 is a block diagram showing the configuration of a vehicle engine control device according to the first embodiment of the present invention in a functionally separated manner.
Figure 3 is a drawing illustrating the internal configuration of the vehicle engine (100) illustrated in Figure 2.
Figure 4 is a drawing for explaining the vehicle engine control operation of the ECU (700) illustrated in Figure 2.
Figure 5 is a flow chart for explaining a vehicle engine control method according to the present invention.

Hereinafter, the present invention will be described in more detail with reference to the attached drawings. It should be noted that in the drawings, the same components are indicated by the same reference numerals wherever possible. Meanwhile, the terms or words used in this specification and the claims should not be interpreted as limited to their usual or dictionary meanings, and should be interpreted as meanings and concepts that conform to the technical idea of the present invention based on the principle that the inventor can appropriately define the concept of the term in order to explain his or her own invention in the best way. Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are only the most preferred embodiments of the present invention, and do not represent all of the technical ideas of the present invention. Therefore, it should be understood that there may be various equivalents and modified examples that can replace them at the time of filing this application.

All terms used herein, unless otherwise defined, have the same meaning as commonly understood by a person of ordinary skill in the art to which the present invention belongs. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with the contextual meaning of the relevant technology, and cannot be interpreted as having an ideal or overly formal meaning that is not explicitly defined in the present invention.

Figure 2 is a drawing schematically illustrating the configuration of a vehicle engine control device according to the first embodiment of the present invention.

Referring to FIG. 2, a vehicle engine control device according to the present invention includes a vehicle engine (100), a fuel supply unit (200), a fuel injector (300), an additive supply unit (400), an additive injector (500), a sensor unit (600), and an ECU (electronic control unit, 700).

The vehicle engine (100) combusts fuel supplied from a fuel supply unit (200) through a fuel injector (300) to provide driving power to the vehicle.

The above-mentioned fuel supply unit (200) includes a fuel tank in which at least one of liquid fuel and gaseous fuel is stored.

The fuel injector (300) is connected to the fuel supply unit (200) and injects fuel into the vehicle engine (100). A number of MPI (multi-point injection) injectors corresponding to the number of engine cylinders may be provided, or a number of GDI (Gasoline Direct Injection) injectors corresponding to the number of engine cylinders may be provided, and both types of injectors may be provided. In addition, a gas injector may be provided alone or additionally provided together with a liquid injector.

The additive supply unit (400) includes an additive tank in which an additive made of a gaseous or liquid substance having a heat-absorbing property is stored. At this time, the additive may be made of one of substances below a certain temperature, including exhaust gas, air, water vapor, and liquid water.

The additive injector (500) is connected to the additive supply unit (400) and injects the additive into the vehicle engine (100).

The sensor unit (600) is composed of at least one sensor that measures the status of the vehicle engine (100), and is configured with at least one sensor including a rail pressure sensor, an exhaust temperature sensor, an engine temperature sensor, a coolant temperature sensor, and an engine rotation speed (RPM) sensor.

The ECU (700) controls the vehicle to drive by injecting fuel and additives into the vehicle engine (100) through the fuel injector (300) and the additive injector (500).

The ECU (700) generates a fuel injection control signal for injecting fuel into the vehicle engine (100) and transmits it to the fuel injector (300), and the fuel injector (300) injects a certain amount of fuel into the vehicle engine (100) in response to the fuel injection control signal. Here, the ECU (700) determines an appropriate fuel injection amount and injection timing based on information collected from the sensor unit (600), and generates an injection control signal corresponding thereto.

In addition, the ECU (700) generates an additive injection control signal for injecting an additive into the vehicle engine (100) and transmits it to the additive injector (500), and the additive injector (500) injects a certain amount of additive into the vehicle engine (100) in response to the additive injection control signal. At this time, the ECU (700) controls the additive to be injected into the vehicle engine (100) during the combustion cycle.

Fig. 3 is a drawing schematically illustrating the configuration of the vehicle engine (100) illustrated in Fig. 2, and illustrates a gasoline engine equipped with a GDI injector. In general, a diesel engine that uses kerosene as fuel is not equipped with a spark plug, and a gasoline engine that uses gasoline as fuel is equipped with a spark plug.

Referring to FIG. 3, a combustion chamber (110) of a vehicle engine (100) is provided with an intake valve (120), an exhaust valve (130), a piston (140), and a spark plug (150), and a fuel injector (300) and an additive injector (500) are arranged so as to directly inject fuel and additives into the combustion chamber (110).

The intake valve (120) is switched to an open or closed state under the control of the ECU (700), and allows outside air to flow into the combustion chamber (110) when in the open state.

The exhaust valve (130) is switched to an open or closed state under the control of the ECU (700), and in the open state, exhaust gas inside the combustion chamber (110) is discharged to the outside.

The piston (140) is arranged to move upward or downward inside the combustion chamber (110) under the control of the ECU (700) to adjust the space inside the combustion chamber (110). It moves upward to narrow the space inside the combustion chamber (110) or moves downward to widen the space inside the combustion chamber (110).

The spark plug (150) causes a spark at high temperature and high pressure by allowing air to flow into the combustion chamber (110), thereby inducing a combustion reaction between the air and fuel inside the combustion chamber (110).

At this time, the ECU (700) injects air into the combustion chamber (110) through the intake valve (120), adjusts the pressure through the piston (140), supplies fuel into the combustion chamber (110) through the fuel injector (300) in a high temperature and high pressure combustion environment with the intake valve (120) open and the exhaust valve (130) closed, and operates the spark plug (150) to cause a combustion reaction in the internal space of the combustion chamber (110), thereby controlling the vehicle to be driven.

In particular, in the present invention, after the combustion reaction in the ECU (700), more specifically, during the combustion cycle in which the combustion reaction is performed, a preset amount of additive is controlled to be supplied into the combustion chamber (110).

That is, as illustrated in Fig. 4, fuel is injected into the combustion chamber (110) at a certain point (X) before the maximum pressure in the general motoring pressure characteristic (Pm) to induce a combustion reaction, and as the combustion reaction occurs, the inside of the combustion chamber (110) appears in the form of a combustion pressure characteristic (Pc). In the present invention, the time after the combustion point (X) that induces the combustion reaction can be set as an additive injection section (D).

Preferably, after a certain amount of combustion reaction has occurred, for example, the time between the point in time when the motoring pressure is maximum and the point in time when the combustion pressure is maximum can be set as the additive injection period (D ₁ ). Accordingly, the ECU (700) can be controlled to inject the additive at a point in time when a certain amount of time has passed since the point in time (X) when the fuel is supplied.

This is to minimize the creation of nitrogen compounds due to the combustion reaction by injecting the additive after the combustion reaction has completed a certain amount, thereby preventing the combustion reaction from being affected even if the temperature inside the combustion chamber, which has increased above a certain level due to the injection of the additive, is lowered to a certain level.

In addition, by additionally adding a certain amount of additive while the inside of the combustion chamber (110) is sealed, the pressure inside the combustion chamber (110) increases, thereby further improving the output of the vehicle engine (100).

Next, the operation of the vehicle engine control device having the above configuration will be described with reference to the flow chart shown in Fig. 5. The following description will be based on the operation of a gasoline engine equipped with a GDI injector and a spark plug.

When the engine operation environment, such as when the ignition is turned on, is reached, the ECU (700) collects engine operation-related sensing information from the sensor unit (600) and generates an injection control signal based on this.

In the above state, the ECU (700) first opens the intake valve (120) and closes the exhaust valve (130) to lower the piston (150) to introduce air into the combustion chamber (110), thereby performing the intake stroke (ST100). At this time, depending on the type of engine, air or a mixture of air and fuel may be introduced through a port connected to the combustion chamber.

Next, the ECU (700) closes the intake valve (120) and performs a compression stroke to compress the air in the combustion chamber (110) by raising the piston (150) (ST200). At this time, the combustion chamber (110) is a sealed environment in which the intake valve (120) and the exhaust valve (130) are closed, and its inside becomes a state of high temperature and high pressure. At this time, depending on the type of engine, the intake port and exhaust port connected to the combustion chamber may be closed.

In the above state, the ECU (700) transmits a fuel injection control signal to the fuel injector (300) to inject fuel into the combustion chamber (110) and ignite the spark plug (140) at the same time to form a combustion environment, thereby performing a combustion cycle in which an explosion occurs due to the combustion reaction of air and fuel (ST300).

Next, the ECU (700) sends an additive injection control signal to the additive injector (400) in the combustion cycle to inject the additive into the combustion chamber (110) (ST400). That is, the additive is directly injected into the combustion chamber (110) while a combustion reaction occurs in the combustion chamber (110).

At this time, the inside of the combustion chamber (110) is in a high temperature state of 1,000℃ or higher, and a gaseous or liquid additive having a lower temperature than this is injected into the combustion chamber (110), thereby lowering the internal temperature of the combustion chamber (110). In particular, the additive is injected into the combustion chamber (110) after the combustion reaction, so that it does not affect the combustion reaction but only lowers the internal temperature of the combustion chamber (110), thereby obtaining the effect of reducing the production of nitrogen oxides.

In addition, by injecting a certain amount of additive into the combustion chamber (110) under high pressure, the inside of the combustion chamber (110) becomes under a higher pressure, and thus the output energy of the engine (100) increases.

Thereafter, the ECU (700) performs an exhaust stroke (ST500) by raising the piston (150) and opening the exhaust valve (120) to discharge exhaust gas existing inside the combustion chamber (110) to the outside (exhaust valve or port).

That is, the vehicle engine is operated through a 4-stroke process of intake->compression->combustion (explosion)->exhaust, but by directly injecting an additive below a certain temperature into the combustion chamber during the combustion stroke section after the start of combustion under sealed conditions where both the intake and exhaust valves are closed, the combustion chamber temperature is lowered during the combustion process, reducing the amount of nitrogen oxides generated while increasing the combustion chamber pressure to improve engine output.

In addition, it goes without saying that the vehicle engine control device and method according to the present invention can be applied to and implemented in various vehicle engines that perform a combustion reaction of fuel and air in a combustion chamber, including a vehicle engine that performs a two-stroke process in which compression and explosion due to combustion occur simultaneously.

100: vehicle engine, 200: fuel supply unit,
300: Fuel injector, 400: Additive supply part,
500: Additive injector, 600: Sensor part,
700: ECU, 710: Memory,
110: Combustion chamber, 120: Intake valve,
130: exhaust valve, 140: piston,
150 : Spark plug.

Claims (8)

A fuel injector that is connected to a fuel supply unit where fuel is stored and injects fuel into the vehicle engine.
An additive injector connected to an additive supply unit storing an additive made of a gaseous or liquid substance that absorbs heat and injecting the additive into a vehicle engine.
A vehicle engine that provides driving force to a vehicle by introducing air into a combustion chamber and combusting fuel injected into the combustion chamber at high temperature and high pressure, and
Consisting of an ECU that controls the supply of fuel and additives to the vehicle engine through a fuel injector and an additive injector,
The above additive injector is positioned so that the additive is directly injected into the combustion chamber of the vehicle engine.
The above ECU is a vehicle engine control device characterized in that it controls the additive to be injected into the combustion chamber through the additive injector between the time when the motoring pressure is maximum and the maximum combustion pressure section of the vehicle engine after the combustion reaction of the vehicle engine has occurred.
In the first paragraph,
A vehicle engine control device, characterized in that the additive is one of substances below a certain temperature, including exhaust gas, air, water vapor, and liquid water.
delete delete In a vehicle engine control method that provides driving force to a vehicle by burning fuel in a combustion chamber of a vehicle engine in an ECU,
In the above ECU, the intake valve connected to the combustion chamber is opened and the exhaust valve is closed, and the piston is moved in the first direction to introduce air or a mixture of air and fuel into the combustion chamber through the intake valve;
The second step is to set the combustion chamber to a high temperature and high pressure state by moving the piston in the second direction while air or a mixture of air and fuel is introduced into the combustion chamber, thereby compressing the inside of the combustion chamber.
The third stage involves injecting fuel into the high-temperature, high-pressure combustion chamber and igniting it at the same time to cause a combustion reaction between fuel and air.
A fourth step of injecting an additive consisting of a gaseous or liquid substance that absorbs heat into the combustion chamber between the point where the motoring pressure is maximum and the point where the maximum combustion pressure of the vehicle engine occurs after the combustion reaction has occurred, and
A vehicle engine control method characterized by comprising a fifth step of moving a piston in a first direction after a combustion reaction is completed to discharge exhaust gas generated by a combustion reaction inside a combustion chamber to the outside through an exhaust valve or port connected to the combustion chamber.
In paragraph 5,
A vehicle engine control method, characterized in that the additive is one of substances below a certain temperature, including exhaust gas, air, water vapor, and liquid water.
delete delete