PRE-COMBUSTION CHAMBER IGNITER, METHANOL ENGINE AND COLD START CONTROL METHOD THEREOF

Abstract

Disclosed is a pre-combustion chamber igniter, a methanol engine and a cold start control method thereof. The pre-combustion chamber igniter includes a housing, nozzles, a fuel injector, a spark plug and heating elements. The heating elements at outer surfaces of the nozzles can heat fuel spray sprayed to an inner wall of a pre-combustion chamber. According to the present disclosure, the pre-combustion chamber is heated using the heating elements during a cold start of the methanol engine, and an excess air coefficient of an interior of the pre-combustion chamber can be controlled between 0.8 and 1.0 to achieve ultra-lean combustion of the engine in a cold start state.

Claims

1. A pre-combustion chamber igniter, comprising: a housing (1), nozzles (2), a fuel injector (3), a spark plug (4) and heating elements (5), inner walls of the nozzles (2) and a bottom of the housing (1) cooperating to form a pre-combustion chamber (6), and at least one nozzle orifice being arranged at a bottom of the pre-combustion chamber (6); the heating elements (5) being attached to outer surfaces of the nozzles (2); the heating elements (5) being configured to heat fuel spray sprayed to a partial inner wall of the pre-combustion chamber (6); and an injection orifice of the fuel injector (3) and a tail end of the spark plug (4) extending into the pre-combustion chamber (6) with an injection direction of the fuel injector (3) facing a direction of the spark plug (4), and spray of the fuel injector being injected to an inner wall of the pre-combustion chamber arranged with the heating elements.

2. The pre-combustion chamber igniter according to claim 1, wherein the pre-combustion chamber (6) is funnel-shaped and sequentially comprises, from the bottom of the housing (1) downward, a first region (61), a second region (63) and a transition region (62) being located between the first region (61) and the second region (63), a volume ratio of the first region (61) to the second region (63) being 1:1; and the heating elements are attached to an exterior of the first region (61) and the transition region (62), and the heating elements are electrically connected to a temperature control switch (12).

3. The pre-combustion chamber igniter according to claim 1, wherein the number of the nozzle orifices is 1-10 with a diameter of 2-8 mm.

4. The pre-combustion chamber igniter according to claim 1, wherein the heating element is selected from one of the following: a heating band, an embedded resistance wire and a heating rod.

5. The pre-combustion chamber igniter according to claim 1, wherein fan-shaped spray formed by the fuel injector (3) is at an angle of 45 to a center axis of the spark plug (4).

6. A methanol engine, comprising a pre-combustion chamber igniter (100) according to claim 1, a cylinder head, a substrate (8), and a movable cavity, the pre-combustion chamber igniter (100), an air inlet end (9) and an air outlet end (10) being arranged on a top of the cylinder head, and the movable cavity being arranged at an interior of the substrate (8) and the cylinder head; and the methanol engine further comprising a temperature control switch (12), the temperature control switch (12) being electrically connected to an alternating current power supply (13), arranged at one side of the pre-combustion chamber igniter (100), and configured to detect a temperature in a pre-combustion chamber (6) and control the opening and closing of heating elements (5).

7. The methanol engine according to claim 6, wherein a volume of the pre-combustion chamber (6) of the pre-combustion chamber igniter (100) is less than 5% of a volume of the movable cavity.

8. A cold start control method for a methanol engine according to claim 6, comprising: heating a pre-combustion chamber (6) by controlling heating elements (5) located on nozzles (2) using a temperature control switch (12) to cause a temperature in the pre-combustion chamber (6) to reach a preset operation temperature; then moving a push rod (11) upward to a compression top dead center with the drive of the engine, injecting fuel by a fuel injector (3), rapidly evaporating the same after contacting an inner wall of the heated pre-combustion chamber (6), mixing the same with the air to form a combustible mixture, and igniting a gas mixture in the pre-combustion chamber (6) by a spark plug (4) at an optimal ignition angle to form a jet flame to enter a movable cavity, a fuel injection amount of the fuel injector being determined according to a volume of the pre-combustion chamber (6), and the optimal ignition angle being determined by a running state of the engine; and controlling an excess air coefficient of an interior of the pre-combustion chamber (6) between 0.8 and 1.0 to achieve ultra-lean combustion of the engine in a cold start state; and the heating elements (5) stopping operations after the methanol engine runs stably, and remaining elements of a cold start device continuing to run.

9. The cold start control method for the methanol engine according to claim 8, wherein the method is also applicable to a cold start of a liquid ammonia fuel engine.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG. 1 is a sectional view of a pre-combustion chamber igniter according to the present disclosure; and

[0024] FIG. 2 is a schematic structural view of a methanol engine mounted with a pre-combustion chamber igniter according to the present disclosure.

[0025] Reference numerals and denotations thereof: [0026] 100pre-combustion chamber igniter; 1housing; 2nozzle; 3fuel injector; 4spark plug; 5heating band; 6pre-combustion chamber; 61first region; 62transition region; 63second region; 7sealing ring; 8substrate; 9air inlet end; 91air inlet pipe; 92air inlet valve; 10air outlet end; 101air outlet pipe; 102air outlet valve; 11push rod; 12temperature control switch; and 13alternating current power supply.

DETAILED DESCRIPTION

[0027] In order to make the objects, technical solutions, beneficial effects and remarkable progress of the examples of the present disclosure clearer, the technical solutions in the examples of the present disclosure will be described clearly and completely with reference to the attached drawings provided in the examples of the present disclosure. Obviously, all the described examples are only some, rather than all examples of the present disclosure. Based on the examples in the present disclosure, all other examples obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present disclosure.

[0028] In the description of the present application, the terms first, second and third are used for descriptive purposes only and are not to be understood as indicating or implying relative importance unless explicitly stated or limited otherwise. The term a plurality means two or more. The terms connected and fixed are to be understood in a broad sense unless otherwise specified or indicated, for example, the connected may be fixedly connected, detachably connected, integrally connected, electrically connected, directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0029] As shown in FIG. 1, a pre-combustion chamber igniter 100 includes a housing 1, nozzles 2, a fuel injector 3, a spark plug 4 and heating bands 5. The nozzles 2 are threadedly connected to a bottom of the housing 1, inner walls of the nozzles 2 and the bottom of the housing 1 cooperate to form a pre-combustion chamber 6, a bottom of the pre-combustion chamber has three nozzle orifices with a diameter of 4 mm, and the nozzle orifices are in communication with the pre-combustion chamber and a movable cavity (namely, a main combustion chamber). The nozzle orifices are uniformly distributed at a bottom of the pre-combustion chamber, so that a jet flame sprayed by the nozzles 2 uniformly covers the whole movable cavity, which successfully ignites a cold gas mixture in the movable cavity and enables the fuel to be fully combusted. Furthermore, a first threaded portion is arranged at an outer side wall of the bottom of the housing 1, and a second threaded portion engaged with the first threaded portion is arranged at an inner side wall of a top of the nozzle 2, thereby achieving a threaded connection of the nozzle 2 to the bottom of the housing 1. This design enhances the connection firmness between the housing 1 and the nozzles 2. When the nozzles 2 are damaged, it is convenient to replace the nozzles 2 quickly and improve the replacement efficiency.

[0030] The pre-combustion chamber 6 is funnel-shaped and sequentially includes, from the bottom of the housing 1 downward, a first region 61, a second region 63 and a transition region located 62 between the first region 61 and the second region 63. A cross-section of the first region 61 is inverted trapezoid-shaped and a cross-section of the second region 63 is rectangular-shaped, and an inner diameter of the transition chamber 63 decreases in a direction away from the first region 61. A volume ratio of the first region to the second region is 1:1. Compared with the traditional pre-combustion chamber, this pre-combustion chamber has a smaller volume, which can reduce energy loss and heat loss.

[0031] The heating bands 5 are attached to the outer surfaces of the nozzles 2, located at an exterior of the first region 61 and the transition region 62, and electrically connected to a temperature control switch 12. The fuel injector 3 is a single-orifice fuel injector arranged at an interior of the housing 1, and an injection orifice of the fuel injector 3 extends into the pre-combustion chamber 6. Fan-shaped spray formed by the fuel injector is at an angle of 45 to a center axis of the spark plug 4, so that an injection direction faces a direction of the spark plug 4, and the spray mainly injects towards the first region 61 and the transition region 62 with larger volumes (as shown in FIG. 1); the spark plug 4 is partially arranged at the interior of the housing 1, and a head of the spark plug 4 is located in an injection chamber 6 and corresponds to the injection orifice of the fuel injector 3.

[0032] Due to this structure design, the spray of the fuel injector 3 is mainly formed in the first region 61 and the transition region 62 of the pre-combustion chamber 6. With the cooperation of the heating bands 5 located on an outer wall of the first region 61 and the transition region 62, the fuel gas mixture inside the pre-combustion chamber 6 can achieve good atomization and evaporation. The spark plug 4 ignites the gas mixture inside the pre-combustion chamber 6, so that the sprayed jet flame ignites the cold gas mixture in the movable cavity (i. e. the main combustion chamber) by the nozzle orifices, thereby achieving reliable cold start of the methanol engine. According to the actual situation, the heating bands 5 can use a structure similar to an embedded resistance wire and a heating rod.

[0033] As shown in FIG. 2, a methanol engine includes a pre-combustion chamber igniter 100, a cylinder head, a substrate 8, an air inlet end 9, an air outlet end 10 and a push rod 11 movably mounted in the substrate 8. The pre-combustion chamber igniter 100, the air inlet end 9 and the air outlet end 10 are arranged at a top of the cylinder head, the air inlet end 9 and the air outlet end 10 are located at two sides of the pre-combustion chamber igniter 100, a movable cavity is arranged at an interior of the substrate 8 and the cylinder head, the push rod 11 abuts against an inner wall of the movable cavity, and a volume of the pre-combustion chamber 6 of the pre-combustion chamber igniter 100 is less than 5% of a volume of the movable cavity, thereby ensuring that existing ignition engines for vehicles can be used without major modifications. The air inlet end 9 includes an air inlet pipe 91 and an air inlet valve 92 for introducing gas, and the air outlet end 10 includes an air outlet pipe 101 and an air outlet valve 102 for discharging gas. The methanol engine further includes a temperature control switch 12. The temperature control switch 12 is electrically connected to an alternating current power supply 13, arranged at one side of the pre-combustion chamber igniter 100, and configured to detect a temperature in a pre-combustion chamber 6 and control the opening and closing of the heating bands.

[0034] When the pre-combustion chamber igniter 100 is mounted, firstly, the fuel injector 3 and the spark plug 4 are mounted on the housing 1, and then the nozzles 2 are threadedly mounted under the housing 1. The heating bands 5 are attached to outer surfaces of the nozzles 2, and are connected to the temperature control switch 12 and the alternating current power supply 13 by a high-temperature-resistant wire, with the injection direction facing the direction of the spark plug 4. The pre-combustion chamber igniter 100 is screwed on the cylinder head through threads on the outer walls of the nozzles 2, which are sideways and located at the side of the air inlet valve 92. The gaps between the nozzles 2 and the cylinder head are sealed with a metal sealing ring 7. In the sealing process, the sealing is realized by slight deformation of the metal sealing ring, thereby improving the sealing performance between the nozzles 2 and the cylinder head.

[0035] The ignition control method for the methanol engine under the cold start condition is as follows.

[0036] Firstly, a pre-combustion chamber 6 is heated by controlling heating bands 5 located on nozzles 2 using a temperature control switch 12 to cause a temperature in the pre-combustion chamber 6 to reach a preset operation temperature. Then, with the drive of the engine, a push rod 11 is moved upward to a compression top dead center, namely, at the first 180 CA (specifically calibrated according to parameters of different engines), the fuel injector 3 injects a small amount of fuel (the amount of the fuel injected needs to be determined according to the volume of the pre-combustion chamber 6), the fuel is rapidly evaporated upon contacting an inner wall of a high temperature pre-combustion chamber 6, and is mixed with the air to form a combustible mixture; a gas mixture in the pre-combustion chamber 6 is ignited by a spark plug 4 at an optimal ignition angle to form a jet flame to enter a movable cavity (a main combustion chamber) to ensure the stable start of the engine. The optimal ignition angle is the compression top dead center where the piston reaches and is determined by a running state of the engine. An excess air coefficient of an interior of the pre-combustion chamber 6 is controlled between 0.8 and 1.0 to achieve ultra-lean combustion of the engine in a cold start state, thereby improving the thermal efficiency.

[0037] After the spark plug 4 successfully ignites the gas mixture in the pre-combustion chamber 6, the interior of the pre-combustion chamber 6 will be ignited firstly, and then multiple jet flames are ejected by the nozzles 2 at an accelerated speed, so that the cold gas mixture in the movable cavity (the main combustion chamber) is successfully ignited and fully combusted. The heating bands 5 stop operating after the methanol engine runs stably.

[0038] In the normal running of the engine, the heating bands 5 are not operated and the remaining elements continue to operate.

[0039] In conclusion, the methanol engine cold start device in the example of the present disclosure improves the ignition performance in the main combustion chamber by introducing a jet flame into the main combustion chamber by heating the pre-combustion chamber 6. Since the main energy of the jet flame comes from fuel combustion, the requirements for battery are not high, the system reliability is higher, and the stability of cold start is better. It is to be noted that the fuels in the examples of the present disclosure include but are not limited to methanol, and can also be extended to the cold start of fuels such as alcohols, ethers and gasoline, and the related art is also instructive for marine and other internal combustion engines to a certain extent.

[0040] In addition, it is to be understood that while the specification has been described in terms of embodiments, not each embodiment only contains an independent technical solution, and that this description is for clarity only. Those skilled in the art are to take the specification as a whole, and the technical solutions in the examples can also be combined appropriately to form other embodiments that can be understood by those skilled in the art.