WO2023160281A1 - Double-main-injecting device of engine and calibration method for cold starting process of engine - Google Patents

Abstract

A double-main-injecting device of an engine and a calibration method for a cold starting process of an engine. The double-main-injecting device of the engine comprises a cylinder piston (1), a cylinder cover (2), a main oil injector (3), and an auxiliary oil injector (4). The cylinder piston is disposed in a cylinder of the engine and is provided with a groove (11); the cylinder cover is disposed above the cylinder piston and defines a combustion chamber (100) with the groove; the main oil injector is disposed on the cylinder cover and is coaxial with the cylinder, and a nozzle of the main oil injector is located in the combustion chamber; the auxiliary oil injector is disposed on the cylinder cover and is arranged at an acute angle with the axis of the cylinder, and a nozzle of the auxiliary oil injector is located in the combustion chamber; and the main oil injector and the auxiliary oil injector are both in communication connection with an ECU.

Description

Calibration method for engine dual main injection device and engine cold start process

This application claims the priority of the Chinese patent application submitted to the China Patent Office on February 25, 2022, with the application number 202210174622.0, and the title of the invention is "a dual main injection device for an engine and a calibration method for an engine cold start process", all of which The contents are incorporated by reference in this application.

technical field

The present application relates to the technical field of engines, for example, it relates to an engine dual main injection device and a calibration method for an engine cold start process.

Background technique

The engine runs in an alpine region. Due to the low ambient temperature, there is poor fuel atomization during the start-up process, and the temperature in the cylinder is low at the end of compression, which is not conducive to the ignition and combustion of diesel. During the cold start process of the engine in the related art, since only one fuel injector is arranged, and in order to take into account the medium and high load work and fuel consumption target requirements, the fuel injection demand is relatively large, which is not conducive to atomization and mixing during the cold start process, and the fuel injection in the combustion chamber There is only one fuel injector to perform a main injection process, which does not make full use of the air in the cylinder to mix with fuel, and the local air utilization rate is low, resulting in a long time for the engine to start until the speed reaches the idle speed.

Contents of the invention

This application provides a dual main injection device for an engine and a calibration method for the cold start process of the engine, which can deal with the time from starting the engine to when the engine speed reaches the idle speed without making full use of the mixing of air and fuel in the cylinder when one fuel injector performs a main injection process longer case.

On the one hand, the application provides a dual main injection device for an engine, comprising:

Cylinder piston with grooves;

The cylinder head is arranged above the cylinder piston and surrounds the groove to form a combustion chamber;

a main fuel injector, arranged on the cylinder head and coaxial with the cylinder, the nozzle of the main fuel injector is located in the combustion chamber;

The auxiliary injector is arranged on the cylinder head and is arranged at an acute angle with the axis of the cylinder, and the nozzle of the auxiliary injector is located in the combustion chamber;

Both the main fuel injector and the auxiliary fuel injector are communicatively connected to the ECU.

Optionally, the nozzle of the auxiliary injector is provided with a plurality of first injection holes, and the nozzle of the auxiliary injector is close to the first injection hole on the side of the main injector. The main axis of the auxiliary injector is at a first set angle, and the first injection hole on the side of the nozzle of the auxiliary injector far away from the main injector is at a second setting angle with the main axis of the auxiliary injector. fixed angle.

Optionally, a plurality of second fuel injection holes are opened on the nozzle of the main fuel injector, and the diameter of the second fuel injection holes is larger than that of the first fuel injection holes.

Optionally, the groove is a circular groove, and the second oil injection hole opens toward the circular groove.

On the other hand, the present application also provides a calibration method for the engine cold start process, which is set to calibrate the parameters of the above-mentioned engine dual main injection device, and the calibration method includes:

detecting the rotational speed of the engine;

When the rotational speed reaches n1, set the basic parameters of the main injector and the auxiliary injector; wherein, the injection rail pressure of the main injector and the injection rail pressure of the auxiliary injector are both is P, the injection advance angle of the auxiliary injector is φ1, the injection quantity of the auxiliary injector is m1, the injection advance angle of the main injector is φ2, and the main injector The fuel injection quantity is m2;

Control the auxiliary injector to inject m1 at the injection advance angle φ1 according to the basic parameters, control the main injector to inject m2 at the injection advance angle φ2 with the preset basic parameters, and collect the combustion parameters of the engine in real time through the combustion analyzer , the output heat release rate change curve;

Calculate the peak value C of the heat release rate derivative of the initial combustion, and the value of C is the peak value of the heat release rate derivative during the period from the start of combustion to the low heat release period, and adjust the φ1 and m1 of the auxiliary injector in the next cycle according to the peak value C of the heat release rate derivative of the initial combustion , until the value of C is in the range of 4-12, at this time, the calibration parameter values φ1 and m1 of the auxiliary injector are obtained;

Keep the calibrated parameter values φ1 and m1 of the calibrated auxiliary injector, collect the combustion parameters of the engine per cycle in real time through the combustion analyzer, and output the heat release rate change curve;

When the speed of the engine reaches n2, the peak value of the heat release rate derivative D of the main combustion is calculated. The value of D is the peak value of the heat release rate derivative during the period from the low heat release period to the end of combustion. The values of φ2 and m2 of the main fuel injector to D are within 3-5 times of the value of C, at this time, the calibration parameter values φ2 and m2 of the main fuel injector are obtained.

Optionally, the range of the basic parameter φ1 is 15°CA-25°CA before top dead center of the cylinder piston, and m1 is 20%-30% of the total fuel injection quantity.

Optionally, the basic parameter φ2 ranges from 5°CA before the top dead center of the cylinder piston to 5°CA after the top dead center, and m2 is 70%-80% of the total fuel injection quantity.

Optionally, if the value of C is less than 4, advance φ1 and increase m1 in the next cycle of auxiliary injector injection, and if the value of C is greater than 12, delay φ1 and decrease m1.

Optionally, if the value of D is less than 0.4C, advance φ2 and increase m2 when injecting the main injector in the next cycle; if the value of D is greater than 0.4C, delay φ2 and decrease m2.

Optionally, after the speed of the engine exceeds the idle speed, close the injection of the secondary injector, adjust the fuel injection quantity of the main fuel injector according to the engine speed, until the speed of the engine is maintained at the idle speed, and calibrate this The injection quantity of the main injector at the time.

This application arranges a sub-injector for dual injection on the basis of the existing combustion system scheme. During the start-up process, the main The injection strategy of the oil interval and injection volume and the calibration of the injection parameters of the main injector and auxiliary injector can realize the rapid start of the engine in a low temperature environment.

Description of drawings

Fig. 1 is the overall structure schematic diagram of a kind of engine double main injection device of the present application;

Fig. 2 is the graph of engine speed changing with time in the calibration method of engine cold start process of the present application;

Fig. 3 is a graph of the heat release rate in the calibration method of the engine cold start process of the present application.

In the picture:

1. Cylinder piston; 11. Groove;

2. Cylinder head;

3. Main injector;

4. Auxiliary injector;

100, combustion chamber.

Detailed ways

In the description of this application, it should be noted that unless otherwise specified 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; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediary, and it can be the internal communication of two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in this application in specific situations.

In this application, unless otherwise expressly specified and limited, a first feature being "on" or "under" a second feature may include direct contact between the first and second features, and may also include the first and second features Not in direct contact but through another characteristic contact between them. Moreover, "above", "above" and "above" the first feature on the second feature include that the first feature is directly above and obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature. "Below", "beneath" and "under" the first feature to the second feature include that the first feature is directly below and obliquely below the second feature, or simply means that the first feature has a lower level than the second feature.

As shown in Fig. 1, the application provides a kind of engine double main injection device, is arranged on the engine, comprises cylinder piston 1, cylinder head 2, main fuel injector 3 and auxiliary fuel injector 4, and cylinder piston 1 is arranged on the engine In the cylinder, there is a groove 11; the cylinder head 2 is arranged above the cylinder piston 1, and the combustion chamber 100 is surrounded by the groove 11; the main injector 3 is arranged on the cylinder head 2 and coaxial with the cylinder, and the main injector The nozzle of the oil injector 3 is located in the combustion chamber 100; the auxiliary injector 4 is arranged on the cylinder head 2 and is arranged at an acute angle α with the axis of the cylinder, and the angle setting range of the acute angle α is 30°-60°, which can achieve a good injection effect. The nozzle of the auxiliary injector 4 is located in the combustion chamber 100; the main injector 3 and the auxiliary injector 4 are both communicatively connected to the ECU.

The present application arranges a secondary injector 4 for realizing double main injection on the basis of the existing diesel combustion system scheme, and the main injector 3 and the secondary injector 4 perform an injection process respectively during the startup process, By adjusting the injection strategy of the two injection intervals and the injection volume, the engine can be started quickly in a low temperature environment.

Exemplarily, the nozzle of the auxiliary injector 4 is provided with a plurality of first injection holes, and the first injection hole on the nozzle of the auxiliary injector 4 near the side of the main injector 3 is connected with the first injection hole of the auxiliary injector 4 The main axis is at the first set angle β1. As an optional solution in this embodiment, the first set angle β1 is selected within the range of 110° to 150° to form a uniform gas mixture at the center of the combustion chamber 100 and make full use of the combustion chamber The air at the center of 100 not only improves the air utilization rate, but also utilizes the strong disturbance of the free jet of the oil jet to increase the strength of the flow field in the cylinder and accelerate the formation of the mixture.

The first fuel injection hole on the nozzle of the auxiliary injector 4 on the side away from the main injector 3 forms a second set angle β2 with the main axis of the auxiliary injector 4, and the second set angle β2 is between 20° and 50° Select within the range, inject fuel into the combustion chamber 100 on one side, and form a uniform mixture along the outer edge of the combustion chamber 100 under the action of the vortex in the cylinder.

Furthermore, in this embodiment, the nozzle of the auxiliary injector 4 is provided with 5 first injection holes, and the side close to the main injector 3 is provided with 3 first injection holes, far away from the main injector. One side of the device 3 is provided with two first fuel injection holes, which can ensure that the inner area of the combustion chamber 100 covered by two fuel injections is sufficient.

Specifically, the nozzle of the main fuel injector 3 is provided with a plurality of second fuel injection holes, and the diameter of the second fuel injection holes is larger than that of the first fuel injection hole. The diameter of the first fuel injection hole is 10% to 25% smaller than that of the second fuel injection hole, and the diameter of the first fuel injection hole on the side away from the main fuel injector 3 is 25% to 25% smaller than that of the second fuel injection hole. 40%, thereby ensuring the atomization effect of the fuel injection of the auxiliary injector 4.

Specifically, the groove 11 is a circular groove, and the second fuel injection hole is opened towards the circular groove, so that the main fuel injector 3 can spray fuel throughout the entire combustion chamber 100, and the spraying is even and the combustion effect is good.

As shown in Figures 2-3, this embodiment also provides a calibration method for the engine cold start process, which is used to control and calibrate the parameters of the above-mentioned engine dual main injection device, including:

Detect the engine speed, when the speed reaches n1;

Set the basic parameters of main injector 3 and auxiliary injector 4, the injection rail pressure is P, the fuel injection advance angle of auxiliary injector 4 is φ1, the fuel injection quantity of auxiliary injector 4 is m1, the main injector The fuel injection advance angle of the fuel injector 3 is φ2, and the fuel injection quantity of the main fuel injector 3 is m2;

Firstly, the sub-injector 4 is controlled to inject m1 at the injection advance angle φ1 according to the basic parameters, and the main injector 3 is controlled to inject m2 at the injection advance angle φ2 with the preset basic parameters. Cyclic combustion parameters, output heat release rate change curve;

The peak value C of the heat release rate derivative of the initial combustion is calculated, and the value of C is the peak value of the heat release rate derivative during the period from the start of combustion to the low heat release period. According to the peak value C of the heat release rate derivative of the initial ignition rate, adjust the φ1 and m1 until the value of C is in the range of 4 to 12, at this time the calibration parameter values φ1 and m1 of the auxiliary injector 4 are obtained;

Keep the calibrated parameter values φ1 and m1 of the calibrated auxiliary injector, collect the combustion parameters of the engine per cycle in real time through the combustion analyzer, and output the heat release rate change curve;

When the speed of the engine reaches n2, the peak value of the heat release rate derivative D of the main combustion is calculated. The value of φ2 and m2 of the main injector 3 is within 3 to 5 times of the value of C. At this time, the calibration parameter values φ2 and m2 of the main injector 3 are obtained, and the φ1, m1, and φ2 and m2 control the injection of the main injector 3 and the auxiliary injector 4 through the ECU, which can realize the rapid cold start of the engine, reduce the time required to reach the idle speed, and improve the cold start efficiency.

Exemplarily, the basic parameter φ1 ranges from 15°C CA to 25°C CA before the top dead center of the piston of the cylinder, and the m1 ranges from 20% to 30% of the total fuel injection quantity.

Exemplarily, the range of the basic parameter φ2 is between 5°CA before the top dead center of the cylinder piston and 5°CA after the top dead center, and m2 is 70%-80% of the total fuel injection quantity.

For example, if the value of C is less than 4, advance φ1 and increase m1 when injecting the secondary injector 4 in the next cycle; if the value of C is greater than 12, delay φ1 and decrease m1.

Furthermore, if the value of D is less than 0.4C, advance φ2 and increase m2 when injecting the main injector 3 in the next cycle; if the value of D is greater than 0.4C, delay φ2 and decrease m2, and finally adjust so that C The values of D and D both meet the settings, and the calibration of the parameters is completed, so as to realize the rapid increase of the speed during the cold start process.

Furthermore, after the engine speed reaches the idle speed, the speed will rise to n3. At this time, the injection of the auxiliary injector 4 will be closed, and the engine speed will fluctuate. At this time, the fuel injection quantity of the main injector 3 will be adjusted. If If the engine speed is higher than the idle speed, then the fuel injection quantity of the main fuel injector 3 is controlled to be reduced; Parameter calibration of injector 3.

Claims (10)

1. A dual main injection device for an engine, comprising:

   The cylinder piston (1) is provided with a groove (11);

   The cylinder head (2) is arranged above the cylinder piston (1), and surrounds the groove (11) to form a combustion chamber (100);

   a main fuel injector (3), arranged on the cylinder head (2) and coaxial with the cylinder, the nozzle of the main fuel injector (3) is located in the combustion chamber (100);

   A secondary injector (4), arranged on the cylinder head (2) at an acute angle to the axis of the cylinder, the nozzle of the secondary injector (4) is located in the combustion chamber (100);

   Both the main injector (3) and the auxiliary injector (4) are communicatively connected to the ECU.
2. The double main injection device of the engine according to claim 1, wherein the nozzle of the auxiliary injector (4) is provided with a plurality of first injection holes, and the nozzle of the auxiliary injector (4) is close to The first injection hole on one side of the main injector (3) is at a first set angle to the main axis of the auxiliary injector (4), and the nozzle of the auxiliary injector (4) is far away from the The first oil injection hole on one side of the main injector (3) forms a second set angle with the main axis of the auxiliary injector (4).
3. According to claim 2, the dual main injection device of the engine, wherein, the nozzle of the main injector (3) is provided with a plurality of second injection holes, and the diameter of the second injection holes is larger than that of the first injection holes. The diameter of a spray hole.
4. The engine dual main injection device according to claim 3, wherein the groove (11) is a circular groove, and the second oil injection hole opens towards the circular groove.
5. A calibration method for an engine cold start process, which is set to calibrate the parameters of the engine dual main injection device described in any one of claims 1-4, the calibration method comprising:

   detecting the rotational speed of the engine;

   When the rotational speed reaches n1, set the basic parameters of the main injector (3) and the auxiliary injector (4); wherein, the injection rail pressure of the main injector (3) and the The injection rail pressures of the auxiliary injectors (4) are all P, the fuel injection advance angle of the auxiliary injectors (4) is φ1, the injection quantity of the auxiliary injectors (4) is m1, and the The fuel injection advance angle of the main fuel injector (3) is φ2, and the fuel injection quantity of the main fuel injector (3) is m2;

   Control the auxiliary injector (4) to inject m1 at the injection advance angle φ1 according to the basic parameters, and control the main injector (3) to inject m2 at the injection advance angle φ2 with the preset basic parameters, and real-time through the combustion analyzer Collect the combustion parameters of the engine per cycle, and output the heat release rate change curve;

   The peak value C of the derivative of the initial combustion heat release rate is calculated, and the value of C is the peak value of the derivative of the heat release rate during the period from the combustion start point to the low heat release period. φ1 and m1, until the value of C is in the range of 4 to 12, the calibration parameter values φ1 and m1 of the secondary injector (4) are obtained at this time;

   Keep the calibrated parameter values φ1 and m1 of the calibrated auxiliary injector (4), collect the combustion parameters of each cycle of the engine in real time through the combustion analyzer, and output the heat release rate change curve;

   When the speed of the engine reaches n2, the peak value of the heat release rate derivative D of the main combustion is calculated. The value of D is the peak value of the heat release rate derivative during the period from the low heat release period to the end of combustion. The φ2 and m2 of the main fuel injector (3) are within the range of 3 to 5 times of the value of C to the value of D, and the calibration parameter values φ2 and m2 of the main fuel injector (3) are obtained at this moment.
6. The calibration method of the engine cold start process according to claim 5, wherein, the range of the basic parameter φ1 is 15°CA to 25°CA before the top dead center of the cylinder piston (1), and m1 is the total fuel injection quantity 20% to 30%.
7. The calibration method for the engine cold start process according to claim 6, wherein the range of the basic parameter φ2 is between 5°CA before the top dead center of the cylinder piston (1) and 5°CA after the top dead center, and m2 is 70% to 80% of the total fuel injection volume.
8. The calibration method for the engine cold start process according to claim 5, wherein, if the value of C is less than 4, advance φ1 and increase m1 when injecting the sub-injector (4) in the next cycle, and if the value of C is greater than 12 , then delay φ1 and reduce m1.
9. The calibration method for the engine cold start process according to claim 8, wherein, if the value of D is less than 0.4C, advance φ2 and increase m2 when injecting the main injector (3) in the next cycle, if the value of D is greater than 0.4C, delay φ2 and reduce m2.
10. The calibration method of the engine cold start process according to claim 9, wherein, after the speed of the engine exceeds the idle speed, the injection of the auxiliary injector (4) is closed, and the main fuel injection is adjusted according to the engine speed The fuel injection quantity of device (3) is maintained at idle speed until the rotating speed of engine, and the fuel injection quantity of said main injector (3) at this moment is calibrated.

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