Methanol engine, injection apparatus and injection control method

Abstract

The present invention belongs to the field of machining. Disclosed are a methanol engine having a stable methanol injection amount, an injection apparatus and an injection control method. The injection apparatus comprises cylinders, wherein a gas intake pipe is provided at gas inlets of the cylinders, a gas exhaust pipe is provided at gas outlets of the cylinders, and at least two methanol injectors are provided in each cylinder; and each cylinder has a gear transmission structure, and the gear transmission structure has displacement sensors, which are used for acquiring displacement change parameters of the gear transmission structure and transmitting parameter data to an external control system, so as to control parameters that affect the injection of methanol injectors. On the basis of operating states such as the rotation speed and load of an engine, the turning-on and turning-off of injectors can be adaptively controlled, and the injection amount of each injector in operation is adjusted, thereby mitigating the impact of methanol injectors on the operation of the engine during the processes of putting the methanol injectors into operation and taking same out of operation.

Description

Methanol engine, injection device and injection control method TECHNICAL FIELD

[0001] The present application belongs to the field of mechanical processing and manufacturing, and particularly relates to an injection control of a methanol engine. BACKGROUND

[0002] The methanol injection amount required by a methanol engine varies greatly with different loads, and the methanol intake port injector (hereinafter referred to as an injector) cannot realize the change of large flow in a limited time due to its structural characteristics, so multiple injectors are designed to be installed in each cylinder, and are sequentially put into work according to the increase of engine load to meet the requirement of injection amount change. Since each injector has a minimum stable injection amount, the total methanol injection amount of the engine will change during the process of sequentially putting the injectors into and out of work, thereby affecting the stable operation of the engine. SUMMARY

[0003] In order to solve at least one of the above technical problems, the present application provides an injection device of a methanol engine with stable methanol injection amount.

[0004] The technical solution adopted by the present application to solve the above technical problems is to provide an injection device of a methanol engine, comprising a cylinder, an intake pipe arranged at an intake port of the cylinder, an exhaust pipe arranged at an exhaust port of the cylinder, and at least two methanol injectors arranged in each cylinder.

[0005] The cylinder and the gear are connected by a transmission structure, and a displacement sensor is used to monitor the displacement change parameter generated in the rotating process of the gear and transmit the parameter data to an external control system.

[0006] According to the present application, further, a controller is used to acquire the engine speed and load, and then control the switching between the multiple methanol injectors.

[0007] According to the present application, further, the gear transmission structure comprises a crankshaft gear and a cam gear matched therewith.

[0008] According to the present application, further, the crankshaft gear is a crankshaft gear with missing teeth, and has a first displacement sensor for collecting the crankshaft angle data of the crankshaft gear.

[0009] According to the present application, further, the cam gear is a crankshaft gear with missing teeth, and has a second displacement sensor. The high and low level signals and missing tooth signals generated by the first displacement sensor of the crankshaft gear are used by the controller to determine the real-time crankshaft angle of each cylinder, and the high and low level signals and missing tooth signals generated by the second displacement sensor installed on the camshaft gear are used by the controller to determine whether each cylinder is in the intake and exhaust stroke or the compression and work stroke, and the methanol injectors are controlled to inject at a specific time in the intake stroke of the cylinder.

[0010] According to the present application, further, the methanol injectors are two.

[0011] The present application also provides a method for controlling the injection of the injection device of the methanol engine, comprising the following steps:

[0012] 1) The controller presets a switching boundary value, and controls the injection of the corresponding injectors;

[0013] 2) When the engine reaches the switching boundary value of step 1), the number of injectors in the injection state is increased or decreased to realize the multi-injector switching.

[0014] According to the present application, further, when the engine load changes from low load to high load in step 2), the number of injectors in the injection state is increased to realize the multi-injector switching; when the engine load changes from high load to low load, the number of injectors in the injection state is decreased, and at least one injector in the injection state is reserved.

[0015] According to the present application, further, the switching load of the engine when the number of injectors is increased is higher than the switching load of the engine when the number of injectors is decreased.

[0016] The present application also provides a methanol engine comprising the injection device of the methanol engine.

[0017] Compared with the prior art, the present application has the following beneficial effects: the start and stop of each injector can be adaptively controlled according to the running state of the engine speed, load and the like, and the injection amount of the working injector can be adjusted, thereby improving the influence of the methanol injector on the engine running during the process of being put into and out of work. BRIEF DESCRIPTION OF DRAWINGS

[0018] Fig. 1 is a schematic diagram of the injection device of the methanol engine according to the present application;

[0019] Fig. 2 is a schematic diagram of the cam gear and the second displacement sensor of the injection device of the methanol engine according to the present application.

[0020] Wherein:

[0021] 100-cylinder, 110-intake pipe, 120-exhaust pipe, 200-methanol injector, 300-crank gear, 310-first displacement sensor, 400-cam gear, 410-second displacement sensor. DETAILED DESCRIPTION

[0022] The application will be further described in connection with the following specific embodiments. It should be understood that these embodiments are only used to illustrate the application and not used to limit the scope of the application. Furthermore, it should be understood that after reading the content of the application, those skilled in the art can make various modifications or changes to the application, and these equivalent forms also fall within the scope of the appended claims.

[0023] As shown in Fig. 1, the application provides a methanol engine injection device, which comprises a cylinder 100, the cylinder 100 is provided with an intake pipe 110 at the intake port, and the cylinder 100 is provided with an exhaust pipe 120 at the exhaust port. Two methanol injectors 200 are arranged in each cylinder 100, and each methanol injector 200 penetrates the cylinder head of the cylinder 100 and has its intake port communicated with the intake pipe 110. The two methanol injectors 200 are selected to work simultaneously or one of them to work according to the engine load, so as to realize the switching of methanol injection. Preferably, the methanol injectors 200 can be three or four. The increase of the number of methanol injectors 200 can increase the flow of methanol and meet the changing demand of injection amount.

[0024] Further, as shown in Fig. 1 and Fig. 2, the cylinder 100 is provided with a crank gear 300 and a cam gear 400 matched with the crank gear 300. The crank gear 300 is a crank gear with missing teeth, and a first displacement sensor 310 is arranged for calculating the crank angle data of the crank gear 300. The cam gear 400 is provided with a second displacement sensor 410. The high and low level signals and the missing tooth signals generated by the first displacement sensor 310 are used to determine the real-time crank angle of each cylinder of the engine by the controller, and the high and low level signals and the missing tooth signals generated by the second displacement sensor 410 installed on the cam shaft gear are used to determine whether each cylinder is in the intake and exhaust stroke or the compression and work stroke by the controller, so as to control the methanol injector 200 to inject at a specific time during the intake stroke of the cylinder. The controller controls whether the switching between the multiple methanol injectors 200 is needed by obtaining the engine speed and load.

[0025] In the embodiment, two methanol injectors 200 are taken as examples, namely, A injector and B injector. When the engine is at low load (e.g., below 60%), the A injector works and the B injector does not work; when the engine is at high load (e.g., above 60%), the A and B injectors work simultaneously. In order to avoid frequent starting and stopping of the B injector when the engine is running near the switching load point, the upper and lower boundaries of the A and B injector switching are set. When the A injector works and the B injector does not work at the switching load of 60%, the B injector will work only when the load rises to 65%; conversely, when the A and B injectors work simultaneously, the B injector will stop working only when the load drops to 55%. That is, the B injector will remain in the original working state in the range of 55%-65%. The switching load in the load rising process is referred to as the upper boundary, i.e., the load of 65% in the above example; and the switching load in the load dropping process is referred to as the lower boundary, i.e., the load of 55% in the above example. In this way, the frequent starting and stopping of the B injector can be effectively avoided. The B injector has two states of starting and stopping, and when the state changes, the total methanol injection amount before and after the change is ensured to be substantially the same, so as to avoid the dramatic change of the engine speed and load. Therefore, the A injector which is always in the working state needs to be adjusted in the injection pulse width and the corresponding injection amount according to the two different states of the starting and stopping of the B injector by the first controller of the A injector. For this purpose, the A injector is designed with different injection control strategies in the two states, for example, when the A injector works alone at a certain working condition of the engine, the injection pulse width is 10 ms, and the corresponding single injection amount is 2 g; when the A and B injectors work simultaneously, the injection pulse width is 6 ms, and the corresponding single injection amount of each is 1 g, so as to ensure that the methanol injection amounts before and after the switching are substantially the same. According to the running state of the B injector, two different injection pulse width control strategies are designed for the A injector to meet the control requirements in different states.

[0026] The basic principles, main features and advantages of the present application are shown and described above. It should be understood by those skilled in the art that the present application is not limited by the above embodiments, and the above embodiments and descriptions in the specification are only the principles of the present application. Various changes and improvements can be made to the present application without departing from the spirit and scope of the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A methanol engine injection device, comprising a cylinder, an air inlet of the cylinder is provided with an air inlet pipe, and an air outlet of the cylinder is provided with an air outlet pipe, characterized in that: At least two methanol injectors are arranged in each cylinder; the cylinder is connected with the gear by a transmission structure, and a displacement sensor is used to monitor the displacement change parameter generated in the rotation process of the gear and transmit the parameter data to the external control system.

2. A fuel injection device for a methanol engine as set forth in claim 1, characterized in that: The controller is used to acquire the engine speed and load and then control the switching among the multiple methanol injectors.

3. A fuel injection device for a methanol engine as set forth in claim 2, characterized in that: The transmission structure includes a crankshaft gear and a cam gear matched with the crankshaft gear.

4. A fuel injection device for a methanol engine as set forth in claim 3, characterized in that: The crankshaft gear is a tooth-lacking crankshaft gear, and a first displacement sensor is arranged on the crankshaft gear to collect the crankshaft angle data of the crankshaft gear.

5. A fuel injection device for a methanol engine as set forth in claim 4, wherein: The cam gear is provided with a second displacement sensor, and the high-low level signal and the tooth-lacking signal generated by the first displacement sensor of the crankshaft gear are used to determine the real-time crankshaft angle of each cylinder of the engine by the controller, and the high-low level signal and the tooth-lacking signal generated by the second displacement sensor arranged on the cam gear are used to determine whether each cylinder is in the intake and exhaust stroke or the compression and work stroke by the controller, and the methanol injectors are controlled to be injected at a specific time in the intake stroke of the cylinder.

6. A fuel injection device for a methanol engine as set forth in claim 1, characterized in that: The methanol injectors are two.

7. A method of injection control for an injection device of a methanol engine, characterized by, The steps are as follows: 1) The controller pre-sets a switching boundary value, and the controller controls the injection or non-injection of the corresponding injectors; 2) When the engine reaches the switching boundary value in step 1), the switching of the multiple injectors is realized by increasing or decreasing the injectors in the injection state.

8. A method of injection control for an injection device of a methanol engine according to claim 7, characterized by: When the engine load changes from low load to high load in step 2), the number of injectors in the injection state is increased to realize the switching of the multiple injectors; when the engine load changes from high load to low load, the number of injectors in the injection state is decreased, and at least one injector in the injection state is reserved.

9. A method of injection control for an injection device of a methanol engine according to claim 7 or 8, characterized in that: When the number of injectors is increased, the switching load of the engine is higher than that when the number of injectors is decreased.

10. A methanol engine characterized by: The methanol injection device of the methanol engine according to any one of claims 1-7. The methanol injection device of the methanol engine according to any one of claims 1-7.

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