阅读说明：本技术 点火角控制方法及其控制装置 (Ignition angle control method and control device thereof ) 是由 曹银波 姚辉 张婵 蔡建 李乐 于 2020-12-29 设计创作，主要内容包括：本发明提供了一种点火角控制方法及其控制装置,其中,所述点火角控制方法包括：首先,根据发动机的转速和负荷将所述发动机的运行工况划分成至少一个区域,所述发动机燃用一辛烷值油品；其次,在每一区域以设定的点火角进行点火,并检测所述发动机的爆震情况；然后,根据所述发动机的爆震情况进行点火角补偿,以使所述点火角达到所在区域对应的爆震边界点火角；所述设定的点火角包括基础辛烷值油品的爆震边界点火角,或者上一区域对应的爆震边界点火角。即通过发动机的爆震情况可以反应出油品的抗爆性,而且根据所述发动机的爆震情况进行点火角补偿,可以避免由于持续爆震造成的发动机本体和催化器损坏,也可以提高燃油经济性。(The invention provides an ignition angle control method and a control device thereof, wherein the ignition angle control method comprises the following steps: firstly, dividing the operation condition of an engine into at least one region according to the rotating speed and the load of the engine, wherein the engine uses an octane number oil product; secondly, igniting at a set ignition angle in each region, and detecting the knocking condition of the engine; then, carrying out ignition angle compensation according to the knocking condition of the engine so as to enable the ignition angle to reach a knocking boundary ignition angle corresponding to the region; the set ignition angle comprises a knock boundary ignition angle of the base octane number oil product or a knock boundary ignition angle corresponding to the previous zone. The anti-knock performance of oil products can be reflected through the knock condition of the engine, and the ignition angle compensation is carried out according to the knock condition of the engine, so that the damage to the engine body and a catalyst caused by continuous knocking can be avoided, and the fuel economy can be improved.)

1. An ignition angle control method characterized by comprising:

step S1: dividing the operating condition of the engine into at least one region according to the rotating speed and the load of the engine, wherein the engine uses an octane number oil product;

step S2: igniting at a set ignition angle in each region, and detecting a knock condition of the engine;

step S3: carrying out ignition angle compensation according to the knocking condition of the engine so as to enable the ignition angle to reach a knocking boundary ignition angle corresponding to the region;

the set ignition angle comprises a knock boundary ignition angle of the base octane number oil product or a knock boundary ignition angle corresponding to the previous zone.

2. The ignition angle control method according to claim 1, characterized in that ignition is performed at a knock boundary ignition angle of a base octane number oil in a region where the engine is first ignited, and an oil octane number is identified based on a knock condition of the engine.

3. The ignition angle control method according to claim 2, characterized in that the octane number of the oil is high if knocking does not occur in the engine, and the ignition angle is advanced by a fixed step until the ignition angle reaches a knock boundary ignition angle corresponding to a region where the ignition angle is located in step S3.

4. The ignition angle control method according to claim 2, characterized in that the engine knocks, and the average retarded ignition angle of knocking exceeds the set average retarded ignition angle threshold lower limit, the octane number of the oil product is low, and in step S3, the ignition angle is retarded in fixed steps until the ignition angle reaches the knock boundary ignition angle corresponding to the zone where the ignition angle is located.

5. The ignition angle control method of claim 2, wherein the octane number is based on the engine knocking and the average retarded ignition angle for knocking does not exceed a set average retarded ignition angle threshold lower limit.

6. The ignition angle control method according to claim 1, further comprising storing the ignition angle compensation value after the ignition angle compensation is performed in the region after step S3.

7. The ignition angle control method according to claim 6, characterized in that when the region in which the engine is located changes, the ignition angle compensation value after the ignition angle compensation is performed in one or more regions next to the region is subjected to the pre-control, and the ignition angle compensation in the next region is performed in accordance with the knocking situation of the engine after the pre-control.

8. The ignition angle control method according to claim 7, wherein the method of pre-controlling the next region with the ignition angle compensation value after the ignition angle compensation in the previous region includes: and the next area is ignited at the knock boundary ignition angle corresponding to the previous area.

9. The ignition angle control method according to claim 7, characterized in that the ignition angle of the next region is advanced by a fixed step until the ignition angle of the next region reaches a knock boundary ignition angle corresponding to the next region if the pre-controlled engine does not knock; and if the pre-controlled engine knocks, retarding the ignition angle by a fixed step length until the ignition angle of the next region reaches the detonation boundary ignition angle corresponding to the next region.

10. An ignition angle control apparatus, characterized by comprising: the device comprises a knock detection unit, a judgment unit and a control unit, wherein the knock detection unit is used for detecting the state of an engine under the current working condition and outputting a signal; the judging unit is used for receiving the signal of the knock measuring unit and judging whether the engine knocks; and the control unit is used for performing ignition angle compensation according to the result of the judging unit.

Technical Field

The invention relates to the technical field of ignition of engines, in particular to an ignition angle control method and an ignition angle control device.

Background

With the tightening of automobile emission regulations, the requirements of countries in the world on the quality of fuel are higher and higher, and the octane number is more and more concerned as an important fuel oil index. By increasing the octane number of the fuel oil, the compression ratio of the fuel oil engine can be correspondingly increased, so that the heat efficiency of the fuel oil engine is increased, and the economy of the fuel oil engine is improved.

The octane number is an important index for expressing the good and bad antiknock performance of the fuel of the spark ignition type engine, the higher the octane number of the fuel, the better the antiknock performance, and the higher compression ratio can be used by the engine, so that the power of the engine can be improved, the fuel can be saved, and therefore, the octane number has important significance for improving the fuel economy performance of a fuel engine. The flame propagation speed is 10-20 m/s when the fuel oil is normally combusted in the cylinder, and can reach 1500-2000 m/s when the fuel oil is combusted by detonation, and the latter can cause the temperature of the cylinder to rise sharply, the fuel oil is incompletely combusted, and the machine strongly vibrates, so that the output power is reduced, and parts are damaged.

The octane numbers of fuel oil of each batch and each gas station are different, if the octane number of the fuel oil added by a driver is lower than the basic octane number used for calibrating the engine, the vehicle can knock continuously in the running process, the ignition angle is delayed greatly, the exhaust temperature is too high, and finally the engine body and the catalyst are damaged; if the octane number of the fuel added by a driver is higher than that of the basic fuel used for calibrating the engine, the actual added octane number is high, the fuel has good antiknock property, and the ignition angle can be properly advanced, so that the engine works at the edge of knocking, and the power property and the fuel economy of the engine are better reflected.

Therefore, how to recognize the octane number of the fuel and how to adjust the ignition angle according to the octane number of the fuel is very important for the power performance and the fuel economy of the engine and to avoid damage to the engine body and the catalyst due to continuous knocking.

Disclosure of Invention

The invention aims to provide an ignition angle control method and an ignition angle control device thereof, which are used for identifying the octane number of oil, improving the power performance and the fuel economy of an engine and avoiding the damage of an engine body and a catalyst caused by continuous detonation.

To achieve the above and other related objects, the present invention provides an ignition angle control method comprising:

step S1: dividing the operating condition of the engine into at least one region according to the rotating speed and the load of the engine, wherein the engine uses an octane number oil product;

step S2: igniting at a set ignition angle in each region, and detecting a knock condition of the engine;

step S3: carrying out ignition angle compensation according to the knocking condition of the engine so as to enable the ignition angle to reach a knocking boundary ignition angle corresponding to the region;

the set ignition angle comprises a knock boundary ignition angle of the base octane number oil product or a knock boundary ignition angle corresponding to the previous zone.

Optionally, in the ignition angle control method, in an area where the engine is ignited for the first time, ignition is performed at a knock boundary ignition angle of a base octane number oil, and an octane number of the oil is identified according to a knock condition of the engine.

Optionally, in the ignition angle control method, if the engine does not knock, the octane number of the oil product is high, and in step S3, the ignition angle is advanced by a fixed step until the ignition angle reaches the knock boundary ignition angle corresponding to the zone where the ignition angle is located.

Optionally, in the ignition angle control method, if the engine knocks and the average retarded ignition angle of the knocking exceeds the set average retarded ignition angle threshold lower limit, the octane number of the oil is low, and in step S3, the ignition angle is retarded by a fixed step until the ignition angle reaches the knock boundary ignition angle corresponding to the located zone.

Optionally, in the ignition angle control method, the engine knocks, and the average retarded ignition angle of knocking does not exceed the set average retarded ignition angle threshold lower limit, the octane number of the oil product is based.

Optionally, in the ignition angle control method, after step S3, the method further includes storing the ignition angle compensation value after the ignition angle compensation is performed in the area.

Optionally, in the ignition angle control method, when the region in which the engine is located changes, the ignition angle compensation value after the ignition angle compensation is performed in more than one region in the next region is pre-controlled, and the ignition angle compensation in the next region is performed according to the knocking situation of the pre-controlled engine.

Optionally, in the ignition angle control method, the method for pre-controlling the next region by using the ignition angle compensation value after the ignition angle compensation is performed in the previous region includes: and the next area is ignited at the knock boundary ignition angle corresponding to the previous area.

Optionally, in the ignition angle control method, if the pre-controlled engine does not knock, advancing the ignition angle of the next region by a fixed step length until the ignition angle of the next region reaches a knock boundary ignition angle corresponding to the next region; and if the pre-controlled engine knocks, retarding the ignition angle by a fixed step length until the ignition angle of the next region reaches the detonation boundary ignition angle corresponding to the next region.

In order to achieve the above and other related objects, the present invention also provides an ignition angle control apparatus comprising: the device comprises a knock detection unit, a judgment unit and a control unit, wherein the knock detection unit is used for detecting the state of an engine under the current working condition and outputting a signal; the judging unit is used for receiving the signal of the knock measuring unit and judging whether the engine knocks; and the control unit is used for performing ignition angle compensation according to the result of the judging unit.

In summary, the ignition angle control method provided by the invention can reflect the anti-knock property of the oil product through the knock condition of the engine, further identify the octane number of the oil product, realize the identification of the oil product, and compensate the ignition angle according to the octane number of the oil product, thereby avoiding the damage of the engine body and the catalyst caused by continuous knock, improving the fuel economy and improving the emission.

Drawings

FIG. 1 is a graph illustrating octane number versus ignition angle for an oil product according to an embodiment of the present invention;

FIG. 2 is a schematic diagram illustrating the variation of ignition angle of a high octane oil in an embodiment of the present invention;

FIG. 3 is a graph illustrating the change in ignition angle for a low octane oil in an embodiment of the present invention;

FIG. 4 is a schematic diagram of region division according to operating conditions in an embodiment of the present invention;

FIG. 5 is a flow chart of different octane oil ignition angle compensation calculations in an embodiment of the present invention;

FIG. 6 is a schematic illustration of the ignition angle pre-control of a high octane oil according to an embodiment of the present invention;

FIG. 7 is a schematic illustration of the ignition angle pre-control of a low octane oil product according to an embodiment of the present invention.

Detailed Description

The ignition angle control method and the control device thereof according to the present invention will be described in further detail with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following description. It is to be noted that the drawings are in a very simplified form and are provided solely for the purpose of facilitating and distinctly facilitating the description of the embodiments of the present invention. As used herein, "and/or" means either or both.

When an engine (oil-burning machine) works, the ignition moment has great influence on the working performance of the engine. Ignition is the spark plug sparking before the piston reaches compression top dead center, igniting the combustible mixture in the combustion chamber. The angle through which the crankshaft rotates during the period from the time of ignition until the piston reaches compression top dead center is referred to as the ignition angle. The ignition angle at which the engine can achieve optimum power, economy, and emissions is referred to as the optimum ignition angle. The combustion of the mixture in the cylinder has a certain speed, that is, a certain time is needed when the spark plug is ignited until the combustible mixture in the cylinder is completely combusted, but the crankshaft can rotate by a large angle in such a short time because the rotating speed of the engine is very high. If the ignition is just performed when the piston reaches the top dead center and the mixture starts to burn, the piston already starts to move downwards, so that the power of the engine is reduced, and therefore, the energy generated by the combustible mixture is required to be effectively utilized through pre-ignition, and the output power of the engine is improved. Therefore, the proper ignition advance angle can maximize the mechanical work of the engine in each cycle, and the engine is over large, easy to explode and over small, the exhaust temperature is raised and the power is reduced.

The octane number is an important index for representing the good and bad anti-explosion performance of the fuel of the spark ignition type engine, and has important significance for improving the fuel economy performance of the fuel engine. When fuel oil is detonated and combusted in the cylinder, the temperature of the cylinder can rise sharply, the fuel oil is incompletely combusted, and the machine vibrates strongly, so that the output power is reduced, and parts are damaged. The octane numbers of fuel oil of each batch and each gas station are different, if the octane number of the fuel oil is lower than that of basic fuel oil used for calibrating an engine, a vehicle can knock continuously in the running process, the ignition angle is delayed greatly, the exhaust temperature is too high, and finally an engine body and a catalyst are damaged; if the octane number of the fuel is higher than that of the basic fuel used for calibrating the engine, the actual added octane number is high, the fuel has good anti-knock property, and the ignition angle can be properly advanced, so that the engine works at the edge of knocking, and the power property and the fuel economy of the engine are better reflected. Referring to FIG. 1, where A is the knock boundary ignition angle for high octane oil; b is the detonation boundary ignition angle of the base octane number oil product; and C is the detonation boundary ignition angle of the low-octane oil product. It can be obtained that the higher the octane number of the oil product, the larger the detonation boundary ignition angle of the fuel, the less the detonation is easy to occur, and the better the explosion resistance is.

In order to identify the octane number of an oil product and avoid damage to an engine body and a catalyst due to continuous knocking, the invention provides an ignition angle control method.

The ignition angle control method includes:

step S1: dividing the operating condition of the engine into at least one region according to the rotating speed and the load of the engine, wherein the engine uses an octane number oil product;

step S2: igniting at a set ignition angle in each region, and detecting a knock condition of the engine;

step S3: and compensating the ignition angle according to the knocking condition of the engine so as to enable the ignition angle to reach the knocking boundary ignition angle corresponding to the region.

The principle of the invention is mainly as follows: the tendency of the engine to knock varies depending on the octane number of the fuel. In step S2, after the fuel is added, the ignition is performed at the set ignition angle in the area where the engine is ignited for the first time, and the knock resistance of the engine is reflected by the knock condition of the engine, so as to identify the octane number of the oil. The set ignition angle can be the ignition angle of a base octane number oil product, and further can be the detonation boundary ignition angle (provided by a manufacturer) of the base octane number oil product, if the engine does not detonate, the octane number of the oil product of the fuel oil is high (namely the fuel oil is a high-octane number oil product); if the engine knocks and the average retarded ignition angle of the knocking exceeds the set average retarded ignition angle threshold lower limit, the octane number of the fuel is low (namely the fuel is a low-octane number oil); if the engine knocks and the average retarded ignition angle for knocking does not exceed the set average retarded ignition angle threshold lower limit, then the octane number of the fuel is based (i.e., the fuel is a base octane number oil). Therefore, the oil product can be identified to a certain extent by the method, and then the ignition angle can be adjusted according to the identified oil product.

Referring to fig. 2, if the octane number of the newly added fuel is high, the ignition angle is advanced by a fixed step, which is set according to the calculation accuracy of the ignition angle, for example, the step of the ignition angle is 0.75, until the ignition angle reaches the knock boundary ignition angle corresponding to the region where the new fuel is located in step S3. In FIG. 2A₁Knock boundary ignition angle for high octane oil under condition 1 (first zone), B₁Knock boundary ignition angle for base octane oil under condition 1; a. the₂Knock boundary ignition angle for high octane oil under condition 2 (second zone), B₂The knock boundary ignition angle for the base octane oil at condition 2. Referring to fig. 3, if the octane number of the newly added fuel is low, the ignition angle is retarded by a fixed step until the ignition angle reaches the ignition angle of the knock boundary corresponding to the region where the new fuel is located, C in fig. 3, in step S3₁Knock boundary ignition angle for low octane oil under condition 1; d₁Setting a lower threshold limit of the average retarded ignition angle of the knocking under the working condition 1; wherein C is₂The detonation boundary ignition angle for a low octane oil under condition 2; d₂The lower threshold limit of the average retarded firing angle for the knock at the set operating condition 2. When high-octane oil is used, the ignition angle is compensated by the method, so that the dynamic property and the fuel economy of the engine can be improved; when a low octane number oil is used, the ignition angle is compensated by the above method, and the damage of the engine body and the catalyst due to the continuous knocking can be avoided.

In the running process of the engine, the working condition is divided into a plurality of areas (the number of the areas is at least 1) according to the rotating speed, the load and the like of the engine, the compensation ignition angle caused by the octane number of each area is different, the accuracy of the ignition angle compensation is directly influenced by the division of the areas, and meanwhile, the workload of data matching of an engine controller is increased. In the actual area division, a cross-area phenomenon may occur. For example, referring to fig. 4, the operating condition is divided into 6 regions according to the engine speed and load (the engine speed and load are gradually increased along the arrow direction in fig. 4), namely a first region 1, a second region, a third region 3, a fourth region 4, a fifth region 5 and a sixth region 6, wherein each region corresponds to one operating condition, and the engine speed and/or load are different under different operating conditions.

Referring to fig. 2 and 3, it can be seen that, in the process of changing the engine load from the operating condition 1 (first region) to the operating condition 2 (second region), if a pre-control mode is not adopted, the ignition angle changes to the detonation boundary of the new oil for a longer time, a certain power loss may exist in the process, and particularly in the process of increasing the load by using the oil with a lower octane number, stronger detonation exists, so that the driving feeling is influenced.

For this reason, it is necessary to pre-control the low octane number ignition angle or the high octane number ignition angle across the zone portion as the engine operating condition changes from one zone to another.

Therefore, when the region in which the engine is located changes, the ignition angle compensation value after the ignition angle compensation is performed in one or more regions in the next region is subjected to pre-control, and the ignition angle compensation in the next region is performed according to the knocking situation of the pre-controlled engine. The method for pre-controlling the next region by the ignition angle compensation value after the ignition angle compensation is carried out in the previous region comprises the following steps: and the next area is ignited at the knock boundary ignition angle corresponding to the previous area.

When the working condition of the engine is changed from the previous region to the next region, before the ignition angle is pre-controlled, the method further comprises the steps of storing an ignition angle compensation value obtained after the previous region is subjected to first ignition angle compensation, and pre-controlling the ignition angle based on the ignition angle compensation value of the previous region. If the pre-controlled engine does not knock, advancing the ignition angle of the next area by a fixed step length until the ignition angle reaches the knock boundary ignition angle corresponding to the next area; and if the pre-controlled engine knocks, retarding the ignition angle by a fixed step length until the ignition angle reaches a knock boundary ignition angle corresponding to the next region. And after the ignition angle reaches the detonation boundary ignition angle corresponding to the next region, the ignition angle compensation value after the ignition angle compensation in the next region is stored.

For example, referring to FIG. 5, the operating conditions of the engine are divided into two regions: a first region (condition 1) and a second region (condition 2), wherein the control method of the ignition angle comprises the following specific steps:

firstly, when an engine is in a working condition 1 and is stable for a period of time, if the engine does not knock, identifying that the octane number of the fuel is high, namely the fuel is a high-octane oil product; if the engine knocks, the octane number of the fuel is identified as low or basic, i.e., the fuel is a low octane number oil or a basic octane number oil.

Secondly, when the engine does not knock, namely the engine is identified as a high-octane oil product, the ignition angle is advanced by a fixed step length, whether knocking exists or not is further identified until slight knocking occurs (namely the ignition angle is advanced to a knocking boundary corresponding to a working condition 1), and a high-octane ignition angle compensation value corresponding to the working condition 1 is stored; when the engine runs to a working condition 2, a high-octane ignition angle compensation value corresponding to the working condition 1 is quoted for pre-control, and if the engine knocks, the ignition angle is delayed by a certain step length until the knocks disappear; if the engine has no knock, the ignition angle is advanced by a certain step length until slight knock occurs (namely the ignition angle is advanced to a knock boundary corresponding to the working condition 2); while the high octane firing angle compensation for condition 2 is stored.

When the engine knocks, the knocking tendency is reduced by retarding the ignition angle; meanwhile, calculating the average detonation retarding ignition angle of the working condition, wherein the calculation method of the average detonation retarding ignition angle is to adopt an ECU to identify the detonation signal of each cylinder, obtain the ignition angle retardation of each cylinder and then calculate the average ignition angle of all the cylinders; when the detonation ignition angle is retarded, continuous detonation still exists, and the detonation average retarded ignition angle of the working condition exceeds the lower limit (provided by a manufacturer) of the detonation average retarded ignition angle threshold of the set working condition 1, the detonation average retarded ignition angle is identified as a low-octane oil product, otherwise, the detonation average retarded ignition angle is identified as a basic-octane oil product; after the low-octane oil product is identified, retarding compensation is carried out on the ignition angle of the working condition 1 by fixed step length until knocking is eliminated (namely, the ignition angle is retarded to a knocking boundary corresponding to the working condition 1), and meanwhile, a low-octane ignition angle compensation value of the working condition 1 is stored; when the operating condition of the engine changes to a working condition 2, pre-controlling the working condition 2 based on the low-octane ignition angle compensation value of the working condition 1; if the engine does not generate continuous knocking, the ignition angle of the working condition 2 is compensated in advance by a fixed step length until the working condition 2 generates slight knocking, and a low-octane ignition angle compensation value of the working condition 2 is stored; and if the working condition 1 enters the working condition 2 for pre-control, and the engine has continuous knocking, retarding and compensating the ignition angle of the working condition 2 by a fixed step length until the knocking of the working condition 2 is eliminated (namely, the ignition angle is retarded to a knocking boundary corresponding to the working condition 2), and storing a low-octane ignition angle compensation value of the working condition 2.

Referring to fig. 6 and 7, which are schematic diagrams illustrating ignition angle pre-control of high-octane oil and low-octane oil, it can be found that, compared with fig. 2 and 3, after the cross-zone pre-control strategy is used, the ignition angle can quickly reach the knock boundary ignition angle corresponding to the octane number of the oil. Thus, using pre-control of the ignition angle may further improve fuel economy and improve emissions with varying operating conditions, but also reduce engine block and catalyst damage due to sustained knock.

The present invention also provides an ignition angle control apparatus comprising: the device comprises a knock detection unit, a judgment unit and a control unit, wherein the knock detection unit is used for detecting the state of an engine under the current working condition and outputting a signal, such as a knock sensor arranged on an engine body; the judging unit is used for receiving the signal of the knock measuring unit and judging whether the engine knocks or not, such as an engine controller; and the control unit is used for compensating the ignition angle according to the result of the judging unit. Also, the control unit may further store a region into which the operating condition of the engine is divided according to the rotational speed and load of the engine. That is, whether knocking is present or not can be determined by means of a knock sensor mounted to the engine body and the signal of the knock sensor recognized by the engine controller. Therefore, the ignition angle control device is used for controlling the ignition angle, does not depend on the index of an oil product, only needs to be based on a traditional knock detection method, and is simple in matching and strong in universality.

The ignition angle control method provided by the invention can be realized by adopting the ignition angle control device, so that the oil product is identified, the damage to an engine body and a catalyst caused by continuous detonation is avoided, the fuel economy is improved, and the emission is improved.

The above description is only for the purpose of describing the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention, and any variations and modifications made by those skilled in the art based on the above disclosure are within the scope of the appended claims.