CN112360640B - Engine misfire monitoring method, device and system - Google Patents

Abstract

The invention belongs to the technical field of vehicles, and particularly relates to a method, a device and a system for monitoring engine fire. The engine misfire monitoring method of the invention comprises the following steps: acquiring a current strain value on a main bearing cover, the rotating speed of an engine and the torque of the engine; the method comprises the steps of obtaining the current cylinder pressure of an air cylinder according to the current strain value on a main bearing cover, obtaining the cylinder pressure of the air cylinder under the specific working condition according to the rotating speed of an engine and the torque of the engine, and controlling an alarm to give an alarm and controlling the engine to enter a torque limiting mode according to the fact that the current cylinder pressure of the air cylinder is smaller than the cylinder pressure of the air cylinder under the specific working condition. According to the method for monitoring the engine fire, the engine is controlled to enter the torque limit and give an alarm through the current strain value of the main bearing, the fire can be monitored, the state of the engine can be corrected, the engine can be prevented from being out of work in other modes, and the normal operation of the engine can be guaranteed.

Description

Engine misfire monitoring method, device and system

technical field

The invention belongs to the technical field of vehicles, and in particular relates to a monitoring method, device and system for engine misfire.

Background technique

There is a misfire problem in the engine. The misfired cylinder of the engine loses its normal working ability due to the inability to burn the fuel normally, while the other cylinders that are not misfired will still work normally, so the engine misfire will first cause the engine to run unstable. A cylinder misfire means that the number of working cylinders (or the number of cycles) is reduced, which will naturally affect the power performance of the engine, and the engine cannot run normally. Among them, the gas engine misfire will also cause excessive unburned gas to enter the after-treatment system and cause abnormal chemical reactions in the after-treatment system, burning the after-treatment system.

In summary, there is a misfire problem in the existing engine, and the engine cannot operate normally.

Contents of the invention

The purpose of the present invention is to at least solve the problems of the existing engine misfire monitoring method, the deviation of the measured value and the low temperature performance. This purpose is achieved through the following technical solutions:

A first aspect of the present invention proposes a method for monitoring engine misfire, wherein the method includes the following steps:

Obtain the current strain value on the main bearing cap, the engine speed and the engine torque;

The current cylinder pressure of the cylinder is obtained according to the current strain value on the main bearing cap, the cylinder pressure of the cylinder under specific working conditions is obtained according to the engine speed and the torque of the engine, and the current cylinder pressure of the cylinder is less than that of the cylinder Under certain working conditions, the cylinder pressure is controlled, the alarm is alarmed and the engine is controlled to enter the torque limiting mode.

In the monitoring method for engine misfire according to the present invention, the current cylinder pressure of the cylinder is obtained according to the current strain value on the main bearing cap, and the control The alarm alarms and controls the engine to enter the limited torque mode. Through the current strain value of the main bearing, controls the engine to enter the limited torque and alarms. It can monitor the misfire, correct the state of the engine or use other methods to avoid engine failure and ensure the normal operation of the engine.

In addition, the monitoring method for engine misfire according to the present invention may also have the following additional technical features:

In some embodiments of the present invention, after obtaining the cylinder pressure of the cylinder under a specific working condition according to the engine speed and the engine torque includes:

The accumulated misfire coefficient exceeds the set misfire coefficient to control the alarm and control the engine to enter the torque limiting mode.

In some embodiments of the present invention, the accumulated misfire coefficient includes:

The current cylinder pressure of the cylinder is lower than the cylinder pressure under the first specific working condition, and the first misfire coefficient is accumulated; the cylinder pressure of the cylinder is lower than the cylinder pressure under the second specific working condition, and the second misfire coefficient is accumulated; The cylinder pressure under the second specific working condition is lower than the cylinder pressure under the first specific working condition, and the second misfire coefficient is greater than the first misfire coefficient.

In some embodiments of the present invention, the controlling the alarm to give an alarm and controlling the engine to enter the torque limiting mode includes:

The alarm is controlled to give an alarm and the throttle opening of the engine is controlled to decrease.

In some embodiments of the present invention, the obtaining the current cylinder pressure of the cylinder according to the current strain value on the main bearing cap includes:

The current cylinder pressure of the cylinder is obtained according to the current strain value on the main bearing cap and the strain-cylinder pressure relationship curve.

In some embodiments of the present invention, the step of obtaining the current cylinder pressure of the cylinder according to the current strain value on the main bearing cap further includes:

The current cylinder pressure of the cylinder is obtained according to the current strain value on the main bearing cap according to the fact that the engine speed and the engine torque do not change within a certain period of time.

Another aspect of the present invention also proposes a monitoring device for engine misfire, which is used to implement the above-mentioned monitoring method for engine misfire, wherein the monitoring device includes: an acquisition unit and a control unit, in:

The acquiring unit is used to acquire the current strain value on the main bearing cap, the rotational speed of the engine and the torque of the engine;

The control unit is used to obtain the current cylinder pressure of the cylinder according to the current strain value on the main bearing cap, obtain the cylinder pressure of the cylinder under specific working conditions according to the engine speed and the torque of the engine, and obtain the cylinder pressure of the cylinder according to the current strain value of the cylinder When the cylinder pressure is lower than the cylinder pressure under the specific working condition of the cylinder, the alarm is controlled to give an alarm and the engine is controlled to enter the torque limiting mode.

Another aspect of the present invention also proposes a monitoring system for engine misfire, the monitoring system for engine misfire includes a memory and the above-mentioned engine misfire monitoring device, and the above-mentioned engine misfire monitoring method is stored in the memory instructions;

The monitoring system for engine misfire also includes: a main bearing cap;

A strain gauge, the strain gauge is arranged on the main bearing cap.

Description of drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the invention. Also throughout the drawings, the same reference numerals are used to denote the same parts. In the attached picture:

Fig. 1 schematically shows a flowchart of a monitoring method for engine misfire according to an embodiment of the present invention;

Fig. 2 schematically shows a logic control block diagram of a monitoring method for engine misfire according to an embodiment of the present invention;

Fig. 3 schematically shows a structural diagram of a monitoring system for engine misfire according to an embodiment of the present invention.

1: Main bearing cap; 2: Strain gauge.

specific embodiment

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided for more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

It should be understood that terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" may also be meant to include the plural forms unless the context clearly dictates otherwise. The terms "comprising", "comprising", "containing" and "having" are inclusive and thus indicate the presence of stated features, steps, operations, elements and/or parts but do not exclude the presence or addition of one or Various other features, steps, operations, elements, components, and/or combinations thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order described or illustrated, unless an order of performance is specifically indicated. It should also be understood that additional or alternative steps may be used.

Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be referred to as These terms are limited. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as "first," "second," and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of example embodiments.

For ease of description, spatial relative terms may be used herein to describe the relationship of one element or feature as shown in the figures with respect to another element or feature, such as "inner", "outer", "inner". ", "Outside", "Below", "Below", "Above", "Above", etc. Such spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" or "beneath" the other elements or features. feature above". Thus, the example term "below" can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

As shown in Figure 1, the monitoring method of engine misfire in the present embodiment, wherein, method comprises the following steps:

S1. Obtain the current strain value on the main bearing cap, the rotational speed of the engine and the torque of the engine;

S2. Obtain the current cylinder pressure of the cylinder according to the current strain value on the main bearing cap, obtain the cylinder pressure of the cylinder under specific working conditions according to the engine speed and engine torque, and obtain the cylinder under specific working conditions according to the current cylinder pressure of the cylinder is less than the cylinder under specific working conditions pressure, control the alarm to alarm and control the engine to enter the limited torque mode.

Specifically, when a gas engine misfires, the explosion pressure in the cylinder is significantly reduced, and the load of the main bearing affected by it will be significantly reduced. By analyzing the change of the current strain value on the main bearing cap, the engine misfire situation can be analyzed Monitor and send an alarm signal to the engine ECU in time.

The amount of strain refers to the change in the geometric shape and size of the specimen when it is affected by external force, temperature, etc., resulting in a change in the range of unit length. It is generally represented by △l/l, where △l refers to the amount of change, and l refers to the range of unit length.

Through the current strain value of the main bearing, the engine is controlled to enter the limited torque and alarm, and it can monitor the misfire, correct the state of the engine or use other methods to avoid engine failure and ensure the normal operation of the engine. The alarm can prompt the driver to stop, dispose of or report for repair in time.

In some embodiments of the present invention, after obtaining the cylinder pressure of the cylinder under specific working conditions according to the rotational speed of the engine and the torque of the engine, the method includes:

Accumulated misfire coefficient, the accumulative misfire coefficient exceeds the set misfire coefficient to control the alarm and control the engine to enter the torque limiting mode.

When the accumulated misfire coefficient exceeds a certain limit, the ECU judges that there is a misfire, and performs an alarm and subsequent protective treatment, otherwise it continues to monitor.

In some embodiments of the invention, the cumulative misfire coefficient includes:

If the current cylinder pressure of the cylinder is lower than the cylinder pressure under the first specific working condition, the first misfire coefficient will be accumulated; if the cylinder pressure of the cylinder is lower than the cylinder pressure under the second specific working condition, the second misfire coefficient will be accumulated; The pressure is lower than the cylinder pressure under the first specific working condition, and the second misfire coefficient is greater than the first misfire coefficient.

If the current cylinder pressure of the cylinder is less than 6 bar under the second specific working condition, the first misfire coefficient is 1, and the current cylinder pressure of the cylinder is less than 10 bar under the first specific working condition, and the second misfire coefficient is 0.5.

Specifically, the present invention is not limited to the two specific working conditions, and can perform specific analysis and calculation according to specific conditions for multiple specific working conditions.

In some embodiments of the present invention, controlling the alarm to alarm and controlling the engine to enter the torque limiting mode includes:

Control the alarm to give an alarm and control the throttle opening of the engine to decrease.

Specifically, the throttle opening of the engine is controlled to decrease, so that the engine operates at a low load. That is, the "torque limiting" mode is turned on to reduce gas injection to achieve the purpose of reducing the unburned gas reaching the after-treatment, and avoid excessive reaction of unburned gas due to misfire in the after-treatment.

In some embodiments of the present invention, obtaining the current cylinder pressure of the cylinder according to the current strain value on the main bearing cap includes:

According to the current strain value on the main bearing cap and the strain-cylinder pressure relationship curve, the current cylinder pressure of the cylinder is obtained.

In some embodiments of the present invention, before obtaining the current cylinder pressure of the cylinder according to the current strain value on the main bearing cap, it also includes:

The current cylinder pressure of the cylinder is obtained according to the current strain value on the main bearing cap according to the engine speed and the engine torque not changing within a certain period of time.

As shown in Figure 2, the system starts after the engine is running, and the ECU judges the engine operating conditions. As the speed and torque change, the engine cylinder pressure also changes in real time. The ECU reads the values of the engine speed and torque, and monitors their changes. When the engine speed and torque are stable within a certain period of time (for example, 10s), the ECU judges that the engine operating condition is suitable for misfire monitoring, and starts the misfire monitoring module.

When the engine is running in a specific monitoring condition, the monitoring module reads the dynamic strain data, analyzes the strain data of the main bearing cap, and obtains the bearing load and cylinder pressure values through calculation; for example, the misfire monitoring module reads within a certain period of time (for example The dynamic strain value of the main bearing cap within 10s) is obtained according to the calibrated strain-cylinder pressure relationship curve embedded in the monitoring module, and the corresponding cylinder pressure is obtained and transmitted to the ECU.

The ECU compares the normal cylinder pressure range under specific working conditions with the cylinder pressure value and the engine working conditions. If the cylinder pressure exceeds the threshold, the ECU will automatically accumulate the misfire coefficient, otherwise continue monitoring; the ECU judges whether it is lower than the normal cylinder pressure range. If the cylinder pressure is lower than the cylinder pressure range, it is determined that there is a misfire. When the misfire coefficient exceeds a certain limit value, the ECU judges that there is a fire, and performs an alarm and subsequent protective treatment, otherwise it continues to monitor. Set the misfire coefficient in the ECU control logic. If a misfire is detected, the misfire coefficient will be +1. Within the set time period (10 minutes), if the misfire coefficient accumulates to more than 10, it is clearly a misfire. The ECU controls the engine torque limit and sends an alarm. Signal.

Another aspect of the present invention also proposes a monitoring device for engine misfire, the monitoring device for engine misfire is used to implement the above-mentioned monitoring method for engine misfire, wherein the monitoring device includes: an acquisition unit and a control unit, wherein:

The acquisition unit is used to acquire the current strain value on the main bearing cap, the rotational speed of the engine and the torque of the engine, wherein the acquisition unit in the present invention is a monitoring module of the engine;

The control unit is used to obtain the current cylinder pressure of the cylinder according to the current strain value on the main bearing cap, obtain the cylinder pressure of the cylinder under specific working conditions according to the engine speed and engine torque, and according to the current cylinder pressure of the cylinder is less than the specific working condition of the cylinder The lower cylinder pressure controls the alarm to alarm and controls the engine to enter the torque limiting mode, wherein the control unit in the present invention is the engine ECU.

As shown in Figure 3, another aspect of the present invention also proposes a monitoring system for engine misfire, the monitoring system for engine misfire includes a memory and the above-mentioned monitoring device for engine misfire, and the above-mentioned monitoring method for engine misfire is stored in the memory instructions;

The monitoring system for engine misfire also includes: main bearing cap 1;

The strain gauge 2 is arranged on the main bearing cap 1 .

In the monitoring method of engine misfire of the present invention, adopt the collection and processing of the current strain value of the strain gauge on the main bearing cap, reflect the stressed of main bearing cap, analyze the generation of misfire phenomenon, and send alarm information to ECU, to engine Fire monitoring.

To sum up, in the monitoring method for engine misfire of the present invention, the current cylinder pressure of the cylinder is obtained according to the current strain value on the main bearing cap, and the alarm is controlled to alarm and Control the engine to enter the limited torque mode, through the current strain value of the main bearing, control the engine to enter the torque limited and alarm, can monitor the misfire, correct the state of the engine or use other methods to avoid engine failure and ensure the normal operation of the engine.

The above are only preferred specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any skilled person in the technical field can easily conceive of changes or changes within the technical scope disclosed in the present invention Replacement should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims (5)

1. a monitoring method for engine misfire, is characterized in that, described method comprises the steps: Obtain the current strain value on the main bearing cap, the engine speed and the engine torque; The current cylinder pressure of the cylinder is obtained according to the current strain value on the main bearing cap, the cylinder pressure of the cylinder under specific working conditions is obtained according to the engine speed and the torque of the engine, and the current cylinder pressure of the cylinder is less than that of the cylinder Under specific working conditions, the cylinder pressure is controlled, the alarm is alarmed and the engine is controlled to enter the limited torque mode; After obtaining the cylinder pressure of the cylinder under specific working conditions according to the speed of the engine and the torque of the engine, it includes: accumulative misfire coefficient, the accumulative misfire coefficient exceeds the set misfire coefficient to control the alarm and control the engine to enter the torque limit mode; The cumulative misfire coefficient includes: The current cylinder pressure of the cylinder is lower than the cylinder pressure under the first specific working condition, and the first misfire coefficient is accumulated; the cylinder pressure of the cylinder is lower than the cylinder pressure under the second specific working condition, and the second misfire coefficient is accumulated; 2. The cylinder pressure under the specific working condition is lower than the cylinder pressure under the first specific working condition, and the second misfire coefficient is greater than the first misfire coefficient; The obtaining the current cylinder pressure of the cylinder according to the current strain value on the main bearing cap includes: The current cylinder pressure of the cylinder is obtained according to the current strain value on the main bearing cap and the strain-cylinder pressure relationship curve. 2. The monitoring method for engine misfire according to claim 1, wherein the controlling the alarm to alarm and controlling the engine to enter the torque limiting mode comprises: The alarm is controlled to give an alarm and the throttle opening of the engine is controlled to decrease. 3. The monitoring method for engine misfire according to claim 1, wherein said obtaining the current cylinder pressure of the cylinder according to the current strain value on the main bearing cap also includes: The current cylinder pressure of the cylinder is obtained according to the current strain value on the main bearing cap according to the fact that the engine speed and the engine torque do not change within a certain period of time. 4. A monitoring device for engine misfire, the monitoring device for engine misfire is used to perform the monitoring method for engine misfire according to claim 1, characterized in that the monitoring device comprises: an acquisition unit and a control unit, wherein: The acquiring unit is used to acquire the current strain value on the main bearing cap, the rotational speed of the engine and the torque of the engine; The control unit is used to obtain the current cylinder pressure of the cylinder according to the current strain value on the main bearing cap, obtain the cylinder pressure of the cylinder under specific working conditions according to the engine speed and the torque of the engine, and obtain the cylinder pressure of the cylinder according to the current strain value of the cylinder When the cylinder pressure is lower than the cylinder pressure under the specific working condition of the cylinder, the alarm is controlled to give an alarm and the engine is controlled to enter the torque limiting mode. 5. A monitoring system for engine misfire, said engine misfire monitoring system comprising a memory and the engine misfire monitoring device according to claim 4, the engine misfire according to any one of claims 1 to 3 is stored in the memory instructions on monitoring methods; The monitoring system for engine misfire also includes: a main bearing cap; A strain gauge, the strain gauge is arranged on the main bearing cap.

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