Engine system and control method for engine system

Abstract

The invention provides an engine system and a control method for the engine system, and relates to the technical field of internal combustion engine parts. The cylinder cover is arranged above the cylinder body in a covering manner; the oil sprayer is mounted on the cylinder cover, and one end extends into the cylinder body; the two glow plugs are installed on the cylinder cover and located on the two opposite sides of the oil sprayer respectively, and each glow plug comprises a heating body stretching into the cylinder body; the two opposite sides of the end, extending into the cylinder body, of the oil sprayer are each provided with an injection hole set, the injection directions of the two injection hole sets face the two heating bodies correspondingly, and each injection hole set comprises at least two injection holes formed in the extending direction of the oil sprayer. According to the invention, the two heating bodies are arranged in the cylinder body, so that the fuel mist beams sprayed by the oil sprayer are filled near the hot surfaces of the two heating bodies to ignite the fuel mist beams near the hot surfaces of the heating bodies, and the ignited fuel mist beams are diffused in the cylinder body, so that the fuel mist beams in the cylinder body are fully and stably combusted.

Description

Technical Field

[0001] At least one embodiment of the present invention relates to the technical field of internal combustion engine components, and particularly to an engine system and a control method for the engine system. Background Art

[0002] With the intensification of the global greenhouse effect, the development of low-carbon and sustainable energy, the diversification, high efficiency, and low carbon of energy utilization are bound to become the development theme. As an important energy fuel, methanol is mostly produced by further reforming coal, and its price is much lower than that of traditional gasoline and diesel fuels. In the future, methanol can be synthesized by preparing green hydrogen from renewable energy such as wind energy, solar energy, and water energy, and then reacting with CO2 emitted in industrial production or directly captured from the air, that is, converting and storing renewable energy in the liquid fuel methanol, so it is also called liquid sunshine or e-fuel.

[0003] There are mainly two technical obstacles in the application of methanol in compression ignition engines. On the one hand, due to its high latent heat of vaporization, methanol will absorb a large amount of heat after entering the engine cylinder, making it difficult to form a homogeneous mixture with uniform mixing, resulting in lower cylinder temperature and pressure and poor methanol evaporation. Not only is it difficult for the engine to ignite stably, but also more formaldehyde and unburned methanol will be generated in the engine cylinder, which are difficult to be treated and purified by the aftertreatment system of existing engines, causing excessive exhaust pollution of the engine. On the other hand, due to the low cetane number of methanol, its ignition delay period is too long, especially it is difficult to ignite stably during cold start.

[0004] To solve the above problems, the following two methods are mainly adopted in the prior art: One method is the dual-fuel ignition method, that is, diesel is used to ignite methanol. However, this method cannot achieve 100% substitution of methanol, and due to the additional arrangement of a fuel system, the system complexity is increased and the cost is increased. Another method is intake air heating. However, although this method ensures stable ignition of methanol, it reduces the charging efficiency, resulting in obvious power shortage of the engine under large load conditions. Summary of the Invention

[0005] In view of this, the present invention provides an engine system, which enables the fuel spray injected into the cylinder by the injector to burn fully and stably.

[0006] According to an embodiment of the present invention, an engine system is provided, including: a cylinder block; a cylinder head covering the cylinder block; an injector installed in the cylinder head with one end extending into the cylinder block; two glow plugs installed in the cylinder head and located on two sides facing each other of the injector respectively, each glow plug including a heating element extending into the cylinder block; wherein, on two sides facing each other of one end of the injector extending into the cylinder block, a spray hole group is respectively arranged, and the spraying directions of the two spray hole groups respectively face the hot surfaces of the two heating elements, and each spray hole group includes at least two spray holes arranged along the extending direction of the injector, so that the fuel spray beam ejected by the injector fills the vicinity of the hot surfaces of the two heating elements to ignite the fuel spray beam near the hot surfaces of the heating elements.

[0007] According to an embodiment of the present invention, the heating temperature of the heating element gradually increases along the extending direction of the hot surface of the heating element, the first flow rates of the fuel spray beams ejected by the two spray holes close to the cylinder head in the two spray hole groups are equal, the second flow rates of the fuel spray beams ejected by the two spray holes far from the cylinder head in the two spray hole groups are equal, and the first flow rate is less than the second flow rate to increase the flow rate of the fuel spray beam near the higher temperature area of the hot surface of the heating element.

[0008] According to an embodiment of the present invention, the two spray holes close to the cylinder head in the two spray hole groups are located on a first circumference with the center of the circle falling on the axis of the injector, and the two spray holes far from the cylinder head in the two spray hole groups are located on a second circumference with the center of the circle falling on the axis of the injector.

[0009] According to an embodiment of the present invention, the spray holes far from the cylinder head in each spray hole group include two first diversion holes, and the axis of the fuel spray beam ejected by each first diversion hole is tangent to the outer wall of the adjacent heating element, so that the fuel spray beam ejected by the first diversion hole falls on the outer wall of the hot surface of the heating element.

[0010] According to an embodiment of the present invention, the spray holes close to the cylinder head in each spray hole group include a second diversion hole and two third diversion holes. Along the circumferential direction of the injector, the two third diversion holes are respectively located on two sides of the second diversion hole. The fuel spray beam ejected by the second diversion hole impacts on the hot surface of the heating element, and the fuel spray beams ejected by the third diversion holes are dispersed near the hot surface of the heating element.

[0011] According to an embodiment of the present invention, the fuel injector includes: a needle valve body with an opening provided at the bottom; a pintle, movably mounted inside the needle valve body along the axial direction of the needle valve body. An oil passage extending along the extension direction of the fuel injector is formed between the outer wall surface of a part of the pintle close to the cylinder head and the inner wall surface of the needle valve body. The inner wall surface of the needle valve body near the end of the oil passage is formed as a first conical surface, and the outer wall surface of the pintle near the end of the oil passage is formed as a second conical surface adapted to the first conical surface. The pintle extends out from the opening, and there is a gap between the pintle and the opening, so that in a state where the second conical surface disengages from the first conical surface, fuel spray in a conical surface distribution is injected into the cylinder interior through the opening to drive the fuel spray ignited by the heating element to diffuse and burn in the cylinder interior.

[0012] According to an embodiment of the present invention, a control method for an engine system is provided, which is applicable to the engine system described in the above embodiment. The control method includes: obtaining the operating condition of the engine system; two of the glow plugs output different heating temperatures in response to the operating condition of the engine system, which is applicable to providing different amounts of heat for igniting the fuel spray in the cylinder interior when the engine system is in different operating conditions.

[0013] According to an embodiment of the present invention, the operating condition is divided into a cold start condition, a small load condition, a medium load condition, and a large load condition in ascending order according to the output torque of the engine system. The temperature inside the engine system increases with the increase of the output torque; when the engine system is in the cold start condition, control the two glow plugs to work at full load; as the engine system runs to the small load condition and the medium load condition, control the heating temperatures output by the two glow plugs to gradually decrease; as the engine system runs to the large load condition, control the two glow plugs to stop working.

[0014] According to an embodiment of the present invention, when the engine system is in the cold start condition, the heating temperature output by the glow plug is 1250°C - 1350°C; when the engine system runs to the small load condition, the heating temperature output by the glow plug is 1050°C - 1150°C; when the engine system runs to the medium load condition, the heating temperature output by the glow plug is 850°C - 950°C.

[0015] According to an embodiment of the present invention, obtaining the operating condition of the engine system includes: determining the output torque of the engine system based on the rotational speed value of a rotational speed sensor connected to the crankshaft of the engine system to determine the operating condition of the engine system; or determining the output torque of the engine system based on the displacement of an accelerator pedal connected to the engine system to determine the operating condition of the engine system.

[0016] For the engine system according to the above embodiment of the present invention, by installing two glow plugs on the cylinder head, the two glow plugs are respectively located on two sides facing each other of the fuel injector, and each glow plug includes a heating element extending into the cylinder block. Further, a spray hole group is respectively arranged on two sides facing each other at one end of the fuel injector extending into the cylinder block, and the spraying directions of the two spray hole groups respectively face the two heating elements. Each spray hole group includes at least two spray holes arranged along the extending direction of the fuel injector, so that the fuel spray ejected by the fuel injector fills near the hot surfaces of the two heating elements to ignite the fuel spray near the hot surfaces of the heating elements, and the ignited fuel spray diffuses inside the cylinder block, thereby enabling the fuel spray inside the cylinder block to burn fully and stably. Description of the Drawings

[0017] Figure 1 is a cross-sectional view of the engine system according to an embodiment of the present invention;

[0018] Figure 2 is a top view of the fuel spray injection process of the engine system according to an embodiment of the present invention.

[0019] In the figure:

[0020] 1 - cylinder block;

[0021] 2 - cylinder head;

[0022] 3 - fuel injector;

[0023] 31 - spray hole group;

[0024] 32 - spray hole; 321 - first shunt hole; 322 - second shunt hole; 323 - third shunt hole;

[0025] 33 - first circumference;

[0026] 34 - second circumference;

[0027] 35 - needle valve body; 351 - opening; 352 - first conical surface;

[0028] 36 - shaft needle; 361 - second conical surface;

[0029] 37 - oil passage;

[0030] 4 - glow plug; 41 - heating element;

[0031] 5 - Piston. Detailed implementation manner

[0032] To make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the following further elaborates on the present invention in detail with reference to specific embodiments and the accompanying drawings.

[0033] According to an inventive concept of an aspect of the present invention, an engine system is provided, including: a cylinder block; a cylinder head covering the cylinder block; an injector installed in the cylinder head with one end extending into the cylinder block; and two glow plugs installed in the cylinder head and located on two sides facing each other of the injector respectively, each glow plug including a heating element extending into the cylinder block; wherein, on two sides facing each other of the end of the injector extending into the cylinder block, a spray hole group is respectively arranged, the spraying directions of the two spray hole groups face the hot surfaces of the two heating elements respectively, and each spray hole group includes at least two spray holes arranged along the extending direction of the injector, so that the fuel spray ejected by the injector fills near the hot surfaces of the two heating elements to ignite the fuel spray near the hot surfaces of the heating elements.

[0034] Figure 1 It is a cross - sectional view of the engine system according to an embodiment of the present invention.

[0035] According to an exemplary embodiment of the present invention, please refer to Figure 1 , an engine system is provided, including a cylinder block 1, a cylinder head 2, an injector 3 and two glow plugs 4. The cylinder head 2 covers the cylinder block 1. The injector 3 is installed in the cylinder head 2 with one end extending into the cylinder block 1. The two glow plugs 4 are installed in the cylinder head 2 and located on two sides facing each other of the injector 3 respectively, and each glow plug 4 includes a heating element 41 extending into the cylinder block 1. Wherein, on two sides facing each other of the end of the injector 3 extending into the cylinder block 1, a spray hole group 31 is respectively arranged, the spraying directions of the two spray hole groups 31 face the hot surfaces of the two heating elements 41 respectively, and each spray hole group 31 includes at least two spray holes 32 arranged along the extending direction of the injector 3, so that the fuel spray ejected by the injector 3 fills near the hot surfaces of the two heating elements 41 to ignite the fuel spray near the hot surfaces of the heating elements 41.

[0036] In this embodiment, two glow plugs 4 are installed on the cylinder head 2. The two glow plugs 4 are respectively located on two sides of the fuel injector 3 facing each other. Each glow plug 4 includes a heating element 41 extending into the interior of the cylinder block 1. Further, a spray hole group 31 is respectively arranged on two sides of the end of the fuel injector 3 extending into the interior of the cylinder block 1 facing each other. The spraying directions of the two spray hole groups 31 respectively face the two heating elements 41. Each spray hole group 31 includes at least two spray holes 32 arranged along the extending direction of the fuel injector 3, so that the fuel spray beam ejected by the fuel injector 3 fills the vicinity of the hot surfaces of the two heating elements 41, to ignite the fuel spray beam near the hot surfaces of the heating elements 41. Through the diffusion of the already ignited fuel spray beam inside the cylinder block 1, the fuel spray beam inside the cylinder block 1 can burn fully and stably.

[0037] It should be noted that in this embodiment, both of the two heating elements 41 can raise the hot surface temperature to 1300 °C within 2 s to stably ignite the fuel spray beam ejected by the fuel injector 3. Among them, in this embodiment, the fuel spray beam ejected by the fuel injector 3 is methanol spray. The cylinder block 1, the cylinder head 2 and the piston 5 form a combustion chamber.

[0038] Further, the glow plug 4 for auxiliary ignition not only has a simple structure, causes less modification to the existing engine system, but also has a relatively low cost. More importantly, as an auxiliary ignition mechanism, the glow plug 4 has a much larger hot surface area and ignition energy than traditional spark plugs and the like, and the matching requirement between its starting time and the fuel injection timing phase of the engine is relatively low. Therefore, applying the glow plug 4 for auxiliary ignition to the engine system (for example, a compression-ignition methanol engine) helps to achieve stable compression ignition under all operating conditions of the engine system (compression-ignition methanol engine).

[0039] In some exemplary embodiments, referring to Figure 1 , the heating temperature of the heating element 41 gradually increases along the extending direction of the heating element 41. The first flow rates of the fuel spray beams ejected by the two spray holes 32 close to the cylinder head 2 in the two spray hole groups 31 are equal, and the second flow rates of the fuel spray beams ejected by the two spray holes 32 far from the cylinder head 2 in the two spray hole groups 31 are equal, and the first flow rate is less than the second flow rate, so as to increase the flow rate of the fuel spray beam near the higher temperature region of the heating element 41.

[0040] Through the above setting method, more fuel in the fuel spray beams ejected by the two spray hole groups 31 is dispersed in the region with a higher hot surface temperature of the heating element 41, so as to increase the heating temperature of the fuel spray beam, thereby improving the thermal efficiency of the fuel spray beam ignited by the heating element 41.

[0041] Furthermore, based on the structure of the existing fuel injector, the injection holes are usually evenly arranged in the circumferential direction on the outer wall surface of the fuel injector, and the space that the glow plug 4 can heat is limited, resulting in difficulty in the stable ignition of the fuel spray (methanol spray) far from the glow plug 4. Compared with the existing fuel injector, the fuel injector 3 of the embodiment of the present invention can distribute the fuel spray near the heating element 41, and more fuel sprays are distributed in the higher temperature region of the heating element 41, improving the thermal efficiency of the fuel spray ignited by the heating element 41.

[0042] It should be noted that, in this embodiment, the second flow rate is 2 to 3 times that of the first flow rate.

[0043] Figure 2 It is a top view of the fuel spray injection process of the engine system according to the embodiment of the present invention.

[0044] In some exemplary embodiments, referring to Figure 1 - Figure 2 , the two injection holes 32 in the two injection hole groups 31 close to the cylinder head 2 are located on the first circumference 33 with the center of the circle falling on the axis of the fuel injector 3, and the two injection holes 32 in the two injection hole groups 31 far from the cylinder head 2 are located on the second circumference 34 with the center of the circle falling on the axis of the fuel injector 3.

[0045] In this embodiment, by arranging the two injection holes 32 in the two injection hole groups 31 close to the cylinder head 2 and the two injection holes 32 far from the cylinder head 2 on two different circumferences respectively, and increasing the injection flow rate of the two injection holes 32 far from the cylinder head 2, the number of injection holes 32 that can be arranged in the small-angle range near the hot surfaces of the two heating elements 41 and the flow rate of the fuel spray are effectively increased. This not only meets the requirement that the fuel injector 3 needs to increase the methanol spray flow rate due to the low calorific value of methanol, but also makes the methanol spray located near the hot surfaces of the two heating elements 41, enabling the methanol spray to achieve rapid and stable ignition under the ignition action of the hot surfaces of the two heating elements 41. The two injection hole groups 31 are symmetrically arranged about the axis of the fuel injector 3.

[0046] In some exemplary embodiments, referring to Figure 1 - Figure 2 , each injection hole 32 in the injection hole group 31 far from the cylinder head 2 includes two first diversion holes 321, and the axis of the fuel spray ejected from each first diversion hole 321 is tangent to the outer wall of the adjacent heating element 41, so that the fuel spray ejected from the first diversion hole 321 falls on the outer wall of the heating element 41.

[0047] Through the above setting method, the fuel spray jet ejected from the first diversion hole 321 is directed towards the area with a relatively high thermal surface temperature of the heating element 41, and the axis of the fuel spray jet ejected from the first diversion hole 321 is tangent to the outer wall of the adjacent heating element 41, increasing the flow rate of the fuel spray jet falling on the area with a relatively high thermal surface temperature of the heating element 41, improving the flow rate of the fuel spray jet ignited by the heating element 41, and thus improving the thermal efficiency of the heating element 41 for igniting the fuel spray jet.

[0048] In some exemplary embodiments, referring to Figure 1 - Figure 2 , among the spray holes 32 in each spray hole group 31 close to the cylinder head 2, there are a second diversion hole 322 and two third diversion holes 323. Along the circumferential direction of the fuel injector 3, the two third diversion holes 323 are respectively located on both sides of the second diversion hole 322. The fuel spray jet ejected from the second diversion hole 322 directly impacts the thermal surface of the heating element 41, and the fuel spray jets ejected from the third diversion holes 323 are dispersed near the thermal surface of the heating element 41.

[0049] Through the above setting method, the number of diversion holes is increased to increase the flow rate of the fuel spray jets ejected from the fuel injector 3 towards the heating element 41. Among them, the fuel spray jet ejected from the second diversion hole 322 directly impacts the thermal surface of the heating element 41, and under the action of the heating element 41, the fuel spray jet ejected from the second diversion hole 322 is ignited. The fuel spray jets ejected from the third diversion holes 323 are dispersed near the thermal surface of the heating element 41, so that the ignited fuel spray jets dispersed near the thermal surface of the heating element 41 contact and ignite the fuel spray jets ejected from the third diversion holes 323 during the diffusion process.

[0050] It should be noted that in this embodiment, the fuel spray jets ejected from the third diversion holes 323 are dispersed in the area within 5 mm from the thermal surface of the heating element 41.

[0051] In some exemplary embodiments, referring to Figure 1 , the fuel injector 3 includes a needle valve body 35 and a pintle 36. An opening 351 is provided at the bottom of the needle valve body 35. The pintle 36 is movably installed inside the needle valve body 35 along the axial direction of the needle valve body 35. An oil passage 37 extending along the extension direction of the fuel injector 3 is formed between a partial outer wall surface of the pintle 36 close to the cylinder head 2 and the inner wall surface of the needle valve body 35. The inner wall surface of the needle valve body 35 near the end of the oil passage 37 is formed as a first conical surface 352, and the outer wall surface of the pintle 36 near the end of the oil passage 37 is formed as a second conical surface 361 adapted to the first conical surface 352. The pintle 36 extends out from the opening 351, and there is a gap between the pintle 36 and the opening 351, so that in the state where the second conical surface 361 is separated from the first conical surface 352, a fuel spray jet distributed in a conical surface is ejected into the cylinder block 1 through the opening 351 to drive the fuel spray jet ignited by the heating element 41 to diffuse and burn inside the cylinder block 1.

[0052] Through the above setting method, the fuel spray (methanol spray) ignited by the heating element 41 can rapidly diffuse and burn inside the cylinder block 1 by means of the fuel spray distributed in a conical surface, flow near other unignited fuel sprays, so as to further ignite more fuel sprays inside the cylinder block 1, thereby further improving the stable ignition performance of the fuel sprays inside the cylinder block 1. The first conical surface 352 and the second conical surface 361 cooperate with each other to play a sealing role. When the fuel injector 3 sprays the fuel spray outward, the second conical surface 361 separates from the first conical surface 352, and the fuel (methanol) is sprayed into the cylinder block 1 through the oil passage 37 and the opening 351 to form a fuel spray, completing the fuel injection. After the fuel injection ends, the second conical surface 361 contacts the first conical surface 352 again to stop the fuel injection.

[0053] According to an exemplary embodiment of the present invention, a control method for an engine system is provided, which is applicable to the engine system described in the above embodiment. The control method includes obtaining the operating condition of the engine system; and two glow plugs 4 output different heating temperatures in response to the operating condition of the engine system, which is applicable to providing different amounts of heat for igniting the fuel spray inside the cylinder block 1 when the engine system is in different operating conditions.

[0054] In this embodiment, by setting the glow plugs 4 to assist in ignition and outputting different heating temperatures in response to the operating condition of the engine system, stable combustion of the engine system (compression-ignition methanol engine) under all operating conditions is achieved, and the modification of the existing engine system is relatively small.

[0055] Furthermore, the ignition energy required by the glow plugs 4 of the engine system is different under different operating conditions. More ignition energy is required under low load, while the engine can operate stably without ignition energy under high load. Therefore, the control method of this embodiment enables the two glow plugs 4 to output different heating temperatures in response to the operating condition of the engine system, not only enabling the engine system to stably ignite under all operating conditions, but also maximizing the overall energy utilization efficiency of the engine system by reasonably controlling the output heating temperature.

[0056] In some exemplary embodiments, the operating condition is divided into a cold start condition, a small load condition, a medium load condition, and a large load condition according to the output torque of the engine system from low to high. The temperature inside the engine system increases with the increase of the output torque. When the engine system is in the cold start condition, the two glow plugs 4 are controlled to work at full load. As the engine system runs to the small load condition and the medium load condition, the heating temperatures output by the two glow plugs 4 are gradually reduced. As the engine system runs to the large load condition, the two glow plugs 4 are controlled to stop working.

[0057] Through the above setting method, the hot surface temperature of the heating element 41 of the glow plug 4 can be adjusted in real time according to different operating conditions of the engine system, which improves the overall energy utilization efficiency of the engine system on the premise of ensuring the stable ignition of the fuel (methanol).

[0058] In some exemplary embodiments, when the engine system is in the cold start condition, the heating temperature output by the glow plug 4 is 1250°C - 1350°C. When the engine system runs to the low load condition, the heating temperature output by the glow plug 4 is 1050°C - 1150°C. When the engine system runs to the medium load condition, the heating temperature output by the glow plug 4 is 850°C - 950°C.

[0059] In this embodiment, when the operating condition of the engine system is the cold start condition, at this time, the thermodynamic conditions inside the cylinder block 1 are poor, and it is difficult for the fuel (methanol) to stably evaporate and catch fire, requiring a large ignition energy. The electronic control unit controls the hot surface temperatures of the two heating elements 41 to be heated to 1250°C - 1350°C, preferably 1300°C. Under the ignition action of the hot surfaces of the two heating elements 41, the fuel sprays (methanol sprays) ejected from the first diversion hole 321 and the second diversion hole 322 in contact with the hot surfaces quickly catch fire. The flame of the already ignited fuel spray quickly spreads to the entire inside of the cylinder block 1 by means of the fuel sprays distributed in a conical surface. The fuel spray (methanol spray) ejected from the third diversion hole 323 also catches fire quickly and stably through flame propagation. At this time, the cold start performance of the engine system is fully guaranteed.

[0060] When the operating condition of the engine system is the low load condition, at this time, the thermodynamic conditions inside the cylinder block 1 are improved. To improve the overall energy utilization efficiency of the engine system, the electronic control unit controls the hot surface temperatures of the two heating elements 41 to be reduced to 1050°C - 1150°C, preferably 1100°C, so as to ensure that the engine system not only ignites stably but also the overall system efficiency is improved.

[0061] When the operating condition of the engine system is the medium load condition, at this time, the thermodynamic conditions inside the cylinder block 1 are further improved. To improve the overall energy utilization efficiency of the engine system, the electronic control unit controls the hot surface temperatures of the two heating elements 41 to be reduced to 850°C - 950°C, preferably 900°C, so as to ensure that the engine system not only ignites stably but also the overall system efficiency is improved.

[0062] When the operating condition of the engine system is in the large load condition, at this time, the thermodynamic conditions inside the cylinder block 1 have been improved to ensure stable ignition of the fuel spray (methanol spray) without the assistance of the glow plug 4 for ignition. Therefore, to improve the energy utilization efficiency of the engine system, the electronic control unit controls the two heating elements 41 to stop working.

[0063] In some exemplary embodiments, obtaining the operating condition of the engine system includes determining the output torque of the engine system based on the rotational speed value of a rotational speed sensor connected to the crankshaft of the engine system to determine the operating condition of the engine system.

[0064] In this embodiment, based on the rotational speed value of the rotational speed sensor connected to the crankshaft of the engine system, the rotational speed of the crankshaft is obtained to determine the output torque of the engine system, thereby determining the operating condition of the engine system. Among them, according to the output torque from low to high, the operating conditions of the engine system are divided into cold start condition, small load condition, medium load condition, and large load condition.

[0065] In addition, obtaining the operating condition of the engine system may also include determining the output torque of the engine system based on the displacement amount of the accelerator pedal connected to the engine system to determine the operating condition of the engine system.

[0066] In this embodiment, based on the displacement amount of the accelerator pedal connected to the engine system, the output torque of the engine system is determined. According to the output torque from low to high, the operating conditions of the engine system are divided into cold start condition, small load condition, medium load condition, and large load condition, thereby determining the operating condition of the engine system.

[0067] The above specific embodiments have further detailed the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An engine system, characterized in that: include: Cylinder body (1); A cylinder cover (2), which is arranged above the cylinder body (1); A fuel injector (3) is mounted on the cylinder head (2) and has one end extending into the cylinder body (1); Two glow plugs (4) are mounted on the cylinder head (2) and are respectively located on two sides of the injector (3) facing each other, and each glow plug (4) includes a heating element (41) extending into the cylinder body (1); Wherein, a spray hole group (31) is respectively arranged on two sides facing each other at one end of the injector (3) extending into the cylinder body (1), and the spray directions of the two spray hole groups (31) face the two heating elements (41) respectively, and each spray hole group (31) includes at least two spray holes (32) arranged along the extension direction of the injector (3), so that the fuel mist sprayed by the injector (3) fills the vicinity of the hot surfaces of the two heating elements (41) to ignite the fuel mist near the hot surfaces of the heating elements (41).

2. The engine system according to claim 1, characterized in that: The heating temperature of the heating element (41) gradually increases along the extension direction of the heating element (41), the first flow rates of the fuel mist jets sprayed from the two nozzle holes (32) in the two nozzle hole groups (31) close to the cylinder head (2) are equal, the second flow rates of the fuel mist jets sprayed from the two nozzle holes (32) in the two nozzle hole groups (31) far from the cylinder head (2) are equal, and the first flow rate is smaller than the second flow rate, so as to increase the flow rate of the fuel mist jet near the higher temperature area of ​​the heating element (41).

3. The engine system according to claim 1, characterized in that: The two spray holes (32) in the two spray hole groups (31) close to the cylinder head (2) are located on a first circumference (33) whose center falls on the axis of the fuel injector (3), and the two spray holes (32) in the two spray hole groups (31) far from the cylinder head (2) are located on a second circumference (34) whose center falls on the axis of the fuel injector (3).

4. The engine system according to claim 1, characterized in that: The spray hole (32) in each spray hole group (31) away from the cylinder head (2) includes two first diversion holes (321), and the axis of the fuel mist sprayed by each first diversion hole (321) is tangent to the outer wall of the adjacent heating element (41), so that the fuel mist sprayed by the first diversion hole (321) falls on the outer wall of the heating element (41).

5. The engine system according to claim 4, characterized in that: The spray holes (32) in each spray hole group (31) close to the cylinder head (2) include a second diverter hole (322) and two third diverter holes (323). Along the circumferential direction of the injector (3), the two third diverter holes (323) are respectively located on both sides of the second diverter hole (322). The fuel mist sprayed by the second diverter hole (322) hits the hot surface of the heating element (41), and the fuel mist sprayed by the third diverter hole (323) is dispersed near the hot surface of the heating element (41).

6. The engine system according to claim 1, characterized in that: The fuel injector (3) comprises: A needle valve body (35) having an opening (351) at the bottom; The needle pin (36) is movably mounted inside the needle valve body (35) along the axial direction of the needle valve body (35); an oil passage (37) extending along the extension direction of the injector (3) is formed between a portion of the outer wall surface of the needle pin (36) close to the cylinder head (2) and an inner wall surface of the needle valve body (35); a first conical surface (352) is formed on the inner wall surface of the needle valve body (35) close to the end of the oil passage (37); and a first conical surface (352) is formed on the outer wall surface of the needle valve body (36) close to the end of the oil passage (37). A second conical surface (361) is formed to match the first conical surface (352), and the axial pin (36) extends from the opening (351). There is a gap between the axial pin (36) and the opening (351), so that when the second conical surface (361) is separated from the first conical surface (352), a fuel mist beam distributed in a conical surface is sprayed into the interior of the cylinder (1) through the opening (351), so as to drive the fuel mist beam ignited by the heating element (41) to diffuse and burn inside the cylinder (1).

7. A control method for an engine system, characterized in that: Applicable to the engine system according to any one of claims 1 to 6 above, the control method comprising: Acquiring the operating condition of the engine system; The two glow plugs (4) output different heating temperatures in response to the operating conditions of the engine system, and are suitable for providing different heat amounts for igniting the fuel mist inside the cylinder (1) when the engine system is in different operating conditions.

8. The control method for an engine system according to claim 7, characterized in that: The operating conditions are divided into cold start conditions, low load conditions, medium load conditions, and high load conditions according to the output torque of the engine system from low to high, and the temperature inside the engine system increases with the increase of the output torque; When the engine system is in a cold start condition, controlling the two glow plugs (4) to work at full load; As the engine system runs to the light load condition and the medium load condition, the heating temperature output by the two glow plugs (4) is controlled to gradually decrease; When the engine system runs into the high-load operating state, the two glow plugs (4) are controlled to stop working.

9. The control method for an engine system according to claim 8, characterized in that: When the engine system is in a cold start condition, the heating temperature output by the glow plug (4) is 1250° C.-1350° C.; When the engine system is running at the low load condition, the heating temperature output by the glow plug (4) is 1050° C.-1150° C.; When the engine system is running at the medium load condition, the heating temperature output by the glow plug (4) is 850° C.-950° C.

10. The control method for an engine system according to claim 7, characterized in that: Obtaining the operating condition of the engine system includes: Determine the output torque of the engine system according to the speed value of the speed sensor connected to the crankshaft of the engine system to determine the operating condition of the engine system; or The output torque of the engine system is determined according to the displacement of an accelerator pedal connected to the engine system to determine the operating condition of the engine system.

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