WO2023169581A1 - Engine combustion system, control method and engine - Google Patents

Abstract

An engine combustion system, a control method and an engine. The combustion system comprises: a cylinder having a cylinder chamber; a piston, the top of which is provided with a combustion chamber in communication with the cylinder chamber, an inner wall of the combustion chamber being provided with a protrusion (1) in a protruding manner, a first swirl pit (2) being formed on one side of the protrusion close to a central axis of the piston, and a second swirl pit (3) being formed on one side of the protrusion away from the central axis of the piston; a fuel injector configured to inject oil into a combustion chamber; and a control assembly capable of comparing a total fuel injection duration with a preset fuel injection duration, determining a main injection mode of the fuel injector according to a comparison result, and controlling the fuel injector to inject fuel into the combustion chamber in the determined main injection mode, so as to inject fuel into the bottom of the corresponding swirl pit, and make the total fuel injection duration of the fuel injector equal to the total fuel injection duration.

Description

Engine combustion system, control method and engine

This application claims priority for the invention patent filed with the China Patent Office on March 11, 2022, with the application number 202210234701.6 and the invention title "An engine combustion system, control method and engine", the entire content of which is incorporated into this application by reference. middle.

Technical field

The present application relates to the field of engines, and in particular to an engine combustion system, a control method and an engine.

Background technique

As fuel prices continue to rise, users are paying more and more attention to the issue of engine energy saving and consumption reduction in the competition for vehicle power systems.

The main injection method of the existing diesel engine cannot make good use of the shape of the combustion chamber to atomize and mix the oil beam. The atomization mixing effect is poor, the combustion effect is poor, and the fuel consumption is large.

Contents of the invention

This application provides an engine combustion system, a control method and an engine, which can make full use of the fresh air in the cylinder chamber, improve the atomization effect of the oil beam, improve the combustion effect, and reduce fuel consumption.

One embodiment provides an engine combustion system, including:

a cylinder having a cylinder chamber;

Piston, the top of the piston is provided with a combustion chamber connected with the cylinder chamber, the inner wall of the combustion chamber is provided with a protrusion, and a plume flow pit is formed on one side of the protrusion close to the central axis of the piston. 1. A plume flow pit is formed on the side of the protrusion away from the central axis of the piston; 2.

A fuel injector configured to inject fuel into the combustion chamber;

A control component that can compare the total injection duration and the preset injection duration, determine the main injection mode of the injector according to the comparison result, and control the injector to use the determined main injection mode. The mode injects fuel into the combustion chamber so that the fuel is injected into the bottom of the corresponding plume pit, and the total injection duration of the injector is equal to the total injection duration.

This application also provides a control method for the above engine combustion system, including:

Obtain the fuel injection volume and rail pressure, and obtain the total fuel injection duration based on the fuel injection volume and rail pressure;

The total injection duration and the preset injection duration are compared, the main injection mode of the fuel injector is determined based on the comparison result, and the fuel injector is controlled to inject fuel into the combustion chamber in the determined main injection mode, so that the fuel is injected into the bottom of the corresponding plume pit, and the total injection time of the injector is equal to the total injection duration.

As an optional technical solution to the above control method of the engine combustion system, when the comparison result is that the total injection duration is less than the preset injection duration, the corresponding main injection mode is a single main injection mode;

When the fuel injector is controlled to inject fuel into the combustion chamber in the single main injection mode, the fuel injected by the fuel injector is injected into the bottom of the plume pit one, and the fuel injector is The total injection time of the oiler is equal to the total injection duration.

As an optional technical solution to the above control method of the engine combustion system, when the comparison result is that the total injection duration is not less than the preset injection duration, the corresponding main injection mode is a dual main injection mode. ;

When controlling the fuel injector to inject fuel into the combustion chamber in the dual main injection mode, the following steps are included:

The fuel injector injection is first controlled so that the fuel injected by the fuel injector is injected into the bottom of the plume pit one and continues for the first injection duration. After the crankshaft rotates through the target angle, the fuel injector injection is controlled again. The oil causes the fuel sprayed by the injector to be injected into the bottom of the plume pit two and continue for the second fuel injection duration;

The sum of the first injection duration and the second injection duration is equal to the total injection duration.

As an optional technical solution to the above control method of the engine combustion system, when the total injection duration is greater than the specified injection duration, the first fuel injection duration MI1 = Δφ, and the second fuel injection duration Period MI2=MI-Δφ;

Wherein, MI represents the total fuel injection duration, Δφ represents the preset fuel injection duration, and the specified fuel injection duration is greater than the preset fuel injection duration.

As an optional technical solution to the above control method of the engine combustion system, when the total fuel injection duration is not greater than the specified fuel injection duration, the first fuel injection duration MI1=1/a×MI, the second injection duration MI2=(1-1/a)×MI;

Wherein, MI represents the total injection duration, a is an injection duration coefficient greater than 1, and the specified injection duration is greater than the preset injection duration.

As an optional technical solution to the above control method of the engine combustion system, obtaining the specified fuel injection duration includes the following steps:

Based on the corresponding relationship between engine speed, engine torque and injection duration coefficient, obtain the injection duration coefficient corresponding to engine speed and engine torque;

The specified fuel injection duration M=a×Δφ, a is the fuel injection duration coefficient greater than 1, and Δφ represents the preset fuel injection duration.

As an optional technical solution to the above control method of the engine combustion system, the target angle is a target angle obtained corresponding to the engine speed and the engine torque based on the mapping relationship between the engine speed, the engine torque and the target angle. .

As an optional technical solution to the above control method of the engine combustion system, the fuel injection from the fuel injector is controlled so that when the fuel injected from the fuel injector is injected into the bottom of the plume pit one, the fuel injection starts. The crankshaft angle corresponding to the starting moment is A, and the crankshaft angle corresponding to the injection end moment is -A;

When the piston is at top dead center, the crankshaft angle is 0°.

This application also provides an engine, including the above engine combustion system.

The engine combustion system control method, engine combustion system and engine provided by this application select the corresponding main injection mode according to the comparison result between the total injection duration and the preset injection duration to inject fuel into the engine during operation. In the corresponding plume pits, the fresh air in the cylinder room can be fully utilized to improve the atomization effect of the oil beam, which is conducive to achieving efficient fuel combustion at a lower excess air coefficient, improving the combustion effect and reducing fuel consumption.

Description of the drawings

Figure 1 is a cross-sectional view of a piston provided by an embodiment of the present application;

Figure 2 is a brief flow chart of an engine combustion system provided by an embodiment of the present application;

Figure 3 is an oil beam path diagram when the fuel injector provided by an embodiment of the present application injects an oil beam into the combustion chamber in a single main injection mode;

Figure 4 shows a fuel injector provided by an embodiment of the present application injecting oil into the combustion chamber in dual main injection mode. Oil beam route map during beam beam;

Figure 5 is a schematic diagram of the crankshaft angle when the fuel injector provided by an embodiment of the present application injects an oil beam into the combustion chamber in dual main injection mode;

Figure 6 is a detailed flow chart of an engine combustion system control method provided by an embodiment of the present application.

In the picture:
1. Protrusion; 2. Volume flow pit one; 3. Volume flow pit two; 4. High temperature area.

Detailed ways

This embodiment provides an engine combustion system, including a piston, a cylinder and an injector. The piston is slidably located in the cylinder chamber of the cylinder. The top of the piston is provided with a combustion chamber connected to the cylinder chamber. The piston is driven by components such as a crankshaft. , capable of reciprocating movement in the cylinder chamber. It should be noted that for piston engines, the combustion chamber in the usual sense refers to the space between the top of the piston and the cylinder head when the piston reaches top dead center. Since the distance between the top of the piston and the cylinder head is very small when the piston is at top dead center, fuel combustion mainly occurs in the pit on the top of the piston. Therefore, people in the industry also call the pit on the top of the piston the combustion chamber. . The combustion chamber in this embodiment refers to the pit on the top of the piston.

Figure 1 is a cross-sectional view of the combustion chamber. As shown in Figure 1, the inner wall of the combustion chamber is provided with a protrusion 1. A curl recess 2 is formed on the side of the protrusion 1 close to the central axis of the piston. The protrusion 1 is far away from the piston. A volume flow pit 2 3 is formed on one side of the central axis.

The bottom center of the combustion chamber is provided with a central boss, and the central boss is a frustum. The combustion chamber is formed by its contour line rotating around the central axis of the piston. The contour line includes the generatrix of the frustum, the first arc, the oblique line and the second arc, which are connected tangentially in sequence. The line is tangent to the top plane of the piston through the transition arc, and the second arc is tangent to the top plane of the piston through the transition arc. Both the first arc and the second arc are concavely arranged.

For example, the angle between the generatrix of the frustum and the central axis of the piston is α/2, the value range of α is 130°-145°, and the radius R1 of the first arc is 4mm-5mm. The generatrix of the frustum and the first arc rotate around the central axis of the piston to form a plume flow pit-2. The maximum depth h1 of the plume flow pit-2 is 6mm-8mm, and the opening diameter of the plume flow pit-2 is d1. .

The angle between the oblique line and the central axis of the piston is β/2. The radius of the second arc is β/2. β is The value range is 120°-135°, and the radius R2 of the second arc is 6mm-8mm. The second arc and the oblique line rotate around the central axis of the piston to form a plume flow pit 2 3. The maximum depth h1 of the plume flow pit 2 3 is 6mm-8mm. The opening diameters of the plume flow pit 2 3 are d2, d1. The ratio range to d2 is 48%-55%, and the ratio range d1 to the diameter of the cylinder chamber is 38%-42%.

The fuel injector is used to inject fuel into the combustion chamber. The engine combustion system provided in this embodiment also includes a control component. The control component is used to compare the total fuel injection duration and the preset fuel injection duration, and determine the fuel injection based on the comparison result. The main injection mode of the injector is controlled, and the injector is controlled to inject fuel into the combustion chamber in the determined main injection mode, so that the fuel is injected into the bottom of the corresponding plume pit, and the total injection time of the injector is equal to the total injection time. Oil duration.

The above control component includes a controller and a fuel injection valve. The fuel injection valve is located on the connecting pipeline between the fuel supply pump and the fuel injector. The fuel injection valve is electrically connected to the controller. The controller can realize injection by controlling the opening and closing of the fuel injection valve. The injector injects fuel or stops injecting fuel.

This embodiment also provides an engine combustion system control method. The engine combustion system control method can be implemented through the above engine combustion system to achieve the purpose of fully utilizing the air in the cylinder chamber and reducing fuel consumption.

As shown in Figure 2, the engine combustion system control method includes the following steps:

S1. Obtain the fuel injection volume and rail pressure, and obtain the total injection duration based on the fuel injection volume and rail pressure;

S2. Compare the total injection duration and the preset injection duration, determine the main injection mode of the injector based on the comparison result, and control the injector to inject fuel into the combustion chamber in the determined main injection mode, so that the fuel It is injected into the bottom of the corresponding plume pit, and the total injection time of the injector is equal to the total injection duration.

As shown in Figure 3, the test found that when the comparison result is that the total injection duration is less than the preset injection duration, using a single main injection can ensure that the oil beam is fully atomized and mixed. In this embodiment, when the comparison result is that the total injection duration is less than the preset injection duration, the corresponding main injection mode is recorded as the single main injection mode; when the injector is controlled to inject fuel into the combustion chamber in the single main injection mode , so that the fuel ejected from the injector is injected into the bottom of the plume pit-2, and the total injection time of the injector is equal to the total injection duration. The fuel injected into the bottom of the plume pit 2 forms a plume, and the oil beam gradually spreads into the combustion chamber, increasing the temperature in the combustion chamber.

As shown in Figure 4, the test found that when the comparison result is that the total injection duration is not less than the preset injection duration, using a single main injection cannot ensure that the oil beam is fully atomized and mixed. In this embodiment, When the comparison result is that the total injection duration is not less than the preset injection duration, the corresponding main injection mode is recorded as the dual main injection mode.

When controlling the fuel injector to inject fuel into the combustion chamber in the dual main injection mode, the following steps are included: first control the fuel injector to inject fuel so that the fuel sprayed by the injector is injected into the bottom of the plume pit 1 and 2 and continues for the first time. During the injection duration, after the crankshaft rotates through the target angle, the injector is controlled to inject fuel so that the fuel ejected from the injector is injected into the bottom of the plume pit 2 3 and continues for the second injection duration; the first injection The sum of the duration and the second injection duration equals the total injection duration.

The fuel injected into the bottom of the plume pit 2 forms a plume, and the oil beam gradually spreads into the combustion chamber, increasing the temperature in the combustion chamber. In the process of the oil beam being sprayed into the plume pit two 3, the oil jet passes through the high temperature area 4 generated by the combustion of the fuel injected into the bottom of the plume pit one 2 and then is sprayed into the bottom of the plume pit two 3. The combustion superposition effect of the double plume flow is used to effectively promote the atomization and evaporation of the oil jet sprayed into the bottom of the plume flow pit 2 and 3, thereby realizing the fuel combustion in the combustion chamber, making full use of the fresh air in the combustion chamber, which is beneficial to the larger combustion chamber. Efficient fuel combustion is achieved under low excess air coefficient.

When the fuel injector is controlled to inject fuel into the combustion chamber in dual main injection mode, in order to improve the atomization effect of the oil beam, the first fuel injection duration and the second fuel injection duration are limited. Specifically, when the total fuel injection duration is greater than the specified fuel injection duration, the first fuel injection duration MI1 = Δφ, and the second fuel injection duration MI2 = MI - Δφ; when the total fuel injection duration is not greater than the specified fuel injection duration During the duration, the first injection duration MI1=1/a×MI, and the second injection duration MI2=(1-1/a)×MI. Among them, MI represents the total injection duration; Δφ represents the preset injection duration, and the specified injection duration is greater than the preset injection duration; a is the injection duration coefficient greater than 1.

By setting the target angle, it is possible to achieve the process in which the oil beam is injected into the plume pit 2 3 and the oil jet passes through the high-temperature area 4 generated by the fuel combustion at the bottom of the plume pit 1 2 before being sprayed into the plume pit 1 . The bottom of pit 2-3. The above target angle is a target angle corresponding to the engine speed and the engine torque obtained based on the mapping relationship between the engine speed, the engine torque and the target angle.

Calibrate the above-mentioned target angle through multiple repeated tests based on engine speed and engine torque to establish a mapping relationship between engine speed, engine torque and target angle. This mapping relationship is embedded in the above-mentioned controller to control the injector to use dual main injection. When the fuel injection mode is used to inject fuel into the combustion chamber, the target angle corresponding to the engine speed and engine torque can be queried based on the above mapping relationship. By selecting the appropriate target angle, the process of the oil jet being sprayed into the plume pit 2 3 can be realized. The fuel jet passes through the high-temperature area 4 generated by fuel combustion at the bottom of the plume pit 2 and is then sprayed into the bottom of the plume pit 2 3 to ensure that the effect of promoting fuel atomization is maximized.

Optionally, the above specified fuel injection duration M=a×Δφ. In order to ensure optimal fuel consumption, different engine speeds and engine torques have different fuel injection duration coefficients. For example, multiple repeated tests are performed based on engine speed and engine torque to calibrate the above-mentioned injection duration coefficient to establish a mapping relationship between engine speed, engine torque and injection duration coefficient, and embed the mapping relationship into the above-mentioned controller. , when controlling the injector to inject fuel into the combustion chamber in the dual main injection mode, based on the above mapping relationship, the injection duration coefficient corresponding to the engine speed and engine torque can be queried, and the specified injection duration coefficient can be calculated based on the queried fuel injection duration coefficient Fuel injection duration.

As shown in Figure 5, the above-mentioned preset injection duration Δφ is calculated based on the shape of the combustion chamber, the position of the injector nozzle hole, and the spray cone angle. For example, based on the shape of the combustion chamber, the position of the injector nozzle and the spray cone angle, the fuel injector is controlled to inject fuel so that the fuel is injected into the bottom of the plume pit - 2, and the minimum crankshaft corresponding to the injection start time is The rotation angle is φ1, and the maximum crankshaft angle corresponding to the end of injection time is recorded as φ2. When the injector is controlled to inject fuel so that the fuel is injected into the bottom of plume pit 1-2, the crankshaft angle corresponding to the starting time of injection is recorded as A1, A1≥φ1, and the crankshaft angle corresponding to the end time of injection is A2, A2 ≤φ2.

According to the shape of the combustion chamber, the position of the injector nozzle hole and the spray cone angle, the fuel injector is controlled to inject fuel so that the fuel is injected into the bottom of plume pit 23. The crankshaft angle corresponding to the starting moment of injection is not less than φ3 . When the fuel injector is controlled to inject fuel so that the fuel is injected into the bottom of plume pit 23, the crankshaft angle corresponding to the starting moment of fuel injection is recorded as B, B≥φ3>φ2.

As for how to calculate the crankshaft angle corresponding to the start time of injection and the crankshaft angle corresponding to the end time of injection when fuel is injected into the combustion chamber in the specified main injection mode based on the shape of the combustion chamber, the position of the injector nozzle and the spray cone angle. It is a prior art in this field and will not be described in detail here.

Preferably, when injecting fuel into the combustion chamber in the single main injection mode, the crankshaft angle corresponding to the end of injection is -A1; when the piston is at top dead center, the crankshaft angle is 0°.

It should be noted that the engine combustion system control method mentioned in this embodiment all refers to the control method when the crankshaft rotates once, that is, -180°-180°.

Exemplarily, Figure 6 shows a control flow of an engine combustion system control method. The engine combustion system control method shown in Figure 6 includes the following steps:

S10. During engine operation, obtain the fuel injection volume and rail pressure, and obtain them based on the fuel injection volume and rail pressure. Total injection duration;

S20. Determine whether the total injection duration is less than the preset injection duration; if so, execute S30; if not, execute S40;

S30. Control the fuel injector to inject fuel into the combustion chamber in single main injection mode and continue the total injection duration;

S40. Determine whether the total injection duration is greater than the specified injection duration. If so, execute S50; if not, execute S60;

S50. Calculate the first fuel injection duration MI1 and the second fuel injection duration MI2, MI1=Δφ, MI2=MI-Δφ; then execute S70;

S60. Calculate the first fuel injection duration MI1 and the second fuel injection duration MI2, MI1=1/a×MI, MI2=(1-1/a)×MI; then execute S70;

S70, first control the fuel injector injection so that the fuel injected by the fuel injector is injected into the bottom of the plume pit 1 and continue for the first injection duration. After the crankshaft rotates through the target angle, control the fuel injector injection again. The fuel injected from the injector is injected into the bottom of the plume pit 2 3 and continues for the second fuel injection duration.

This embodiment also provides an engine, including the above engine combustion system.

In the description of this application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. The indicated orientation or positional relationship is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description. It does not indicate or imply that the device or element referred to must have a specific orientation or a specific orientation. construction and operation, and therefore should not be construed as limitations on this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions.

In the description of this application, it should be noted that, unless otherwise clearly stated and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection. Connection, or integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be an internal connection between two components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood on a case-by-case basis.

Claims (10)

1. An engine combustion system including:

   a cylinder having a cylinder chamber;

   Piston, the top of the piston is provided with a combustion chamber connected with the cylinder chamber, the inner wall of the combustion chamber is provided with a protrusion (1), the protrusion (1) is close to the side of the central axis of the piston One (2) plume flow pit is formed, and two (3) plume flow pits are formed on the side of the protrusion (1) away from the central axis of the piston;

   A fuel injector configured to inject fuel into the combustion chamber;

   A control component that can compare the total injection duration and the preset injection duration, determine the main injection mode of the injector according to the comparison result, and control the injector to use the determined main injection mode. The mode injects fuel into the combustion chamber so that the fuel is injected into the bottom of the corresponding plume pit, and the total injection duration of the injector is equal to the total injection duration.
2. A control method applied to the engine combustion system of claim 1, comprising:

   Obtain the fuel injection volume and rail pressure, and obtain the total fuel injection duration based on the fuel injection volume and rail pressure;

   The total injection duration and the preset injection duration are compared, the main injection mode of the fuel injector is determined based on the comparison result, and the fuel injector is controlled to inject fuel into the combustion chamber in the determined main injection mode, so that the fuel is injected into the bottom of the corresponding plume pit, and the total injection time of the injector is equal to the total injection duration.
3. The control method of an engine combustion system according to claim 2, wherein when the comparison result is that the total injection duration is less than the preset injection duration, the corresponding main injection mode is a single main injection mode;

   When the fuel injector is controlled to inject fuel into the combustion chamber in the single main injection mode, the fuel injected by the fuel injector is injected into the bottom of the plume pit one (2), and causes The total fuel injection duration of the fuel injector is equal to the total fuel injection duration.
4. The control method of the engine combustion system according to claim 2, wherein when the comparison result is that the total injection duration is not less than the preset injection duration, the corresponding main injection mode is a dual main injection mode;

   When controlling the fuel injector to inject fuel into the combustion chamber in the dual main injection mode, the following steps are included:

   First, control the fuel injection of the fuel injector so that the fuel sprayed by the fuel injector is injected into the plume pit. (2) and continue the first injection duration. After the crankshaft rotates through the target angle, the injector is controlled to inject fuel so that the fuel sprayed by the injector is injected into the plume pit two (3) bottom and last for the second injection duration;

   The sum of the first injection duration and the second injection duration is equal to the total injection duration.
5. The control method of an engine combustion system according to claim 4, wherein:

   When the total fuel injection duration is greater than the specified fuel injection duration, the first fuel injection duration MI1 = Δφ, and the second fuel injection duration MI2 = MI-Δφ;

   Wherein, MI represents the total fuel injection duration, Δφ represents the preset fuel injection duration, and the specified fuel injection duration is greater than the preset fuel injection duration.
6. The control method of an engine combustion system according to claim 4, wherein:

   When the total fuel injection duration is not greater than the specified fuel injection duration, the first fuel injection duration MI1 = 1/a × MI, and the second fuel injection duration MI2 = (1-1/a) ×MI;

   Wherein, MI represents the total injection duration, a is an injection duration coefficient greater than 1, and the specified injection duration is greater than the preset injection duration.
7. The control method of an engine combustion system according to claim 5 or 6, wherein obtaining the specified fuel injection duration includes the following steps:

   Based on the corresponding relationship between engine speed, engine torque and injection duration coefficient, obtain the injection duration coefficient corresponding to engine speed and engine torque;

   The specified fuel injection duration M=a×Δφ, a is the fuel injection duration coefficient greater than 1, and Δφ represents the preset fuel injection duration.
8. The control method of the engine combustion system according to any one of claims 4 to 6, wherein the target angle is based on the mapping relationship between the engine speed, the engine torque and the target angle, and the obtained angle is related to the engine speed and the engine torque. corresponding target angle.
9. The control method of the engine combustion system according to any one of claims 3 to 6, wherein the fuel injection of the fuel injector is controlled so that the fuel injected by the fuel injector is injected into the plume pit one (2) At the bottom of , the crankshaft angle corresponding to the start time of injection is A, and the crankshaft angle corresponding to the end time of injection is -A;

   When the piston is at top dead center, the crankshaft angle is 0°.
10. An engine including the engine combustion system of claim 1.