Diesel and methanol dual-fuel engine control system and method

Abstract

The invention discloses a diesel and methanol dual-fuel engine control system and method, relates to the technical field of engine control, can be applied to a diesel engine with mechanical or electric control type oil supply, and in the control system, the current load of the engine is determined through a signal of an accelerator pedal position sensor, and an accelerator actuator or a diesel nozzle is controlled; the amount of diesel oil injected into the engine cylinder body is adjusted, then work of the electric control throttle valve and the methanol injector is controlled, the air inlet amount of the engine and the amount of methanol injected into the air inlet pipeline are controlled respectively, and combustible mixed gas capable of adapting to amount adjustment is formed and enters the engine cylinder body to be combusted. According to the method, the mass adjusting mode of the original diesel engine load is changed into the mode mainly based on the amount adjusting mode, the methanol injection amount is controlled to be matched with the air inlet amount, and a small amount of diesel oil is adopted for ignition, so that the method has important practical significance for relieving the tension condition of vehicle fuel supply, improving the economic benefit and reducing the pollution of PM2.5 to the environment.

Description

Technical Field

[0001] The present application relates to the field of engine control technology, and in particular to a diesel and methanol dual-fuel engine control system and method. Background Art

[0002] When diesel and methanol are used as dual fuels in a diesel engine, existing technologies face a series of challenges. These problems include, but are not limited to: the ignition ranges of the two fuels do not match, resulting in reduced engine performance; in addition, as the proportion of methanol increases, the cetane number may decrease, resulting in difficulty in ignition or misfire in the diesel engine, and because the compression ratio of methanol is higher than that of diesel, it will also cause the compression ratio to increase. In addition, from the perspective of environmental pollution, when methanol and diesel are burned in a lean mixture state, the pollutants emitted may not only not decrease, but may increase significantly.

[0003] In summary, in response to the problems faced by traditional diesel engines when using diesel and methanol dual fuels, an improved diesel injection engine control system is proposed to enable it to adapt to the operation of diesel and methanol dual fuels. This has important practical significance for alleviating the tense situation of vehicle fuel supply, improving economic benefits and reducing PM2.5 pollution to the environment. Summary of the invention

[0004] The purpose of the present application is to provide a diesel and methanol dual-fuel engine control system and method, which can adapt to the operation of diesel engines with different fuel supply modes when using diesel and methanol dual fuels.

[0005] To achieve the above objectives, this application provides the following solutions:

[0006] In the first aspect, the present application provides a diesel and methanol dual-fuel engine control system, which is applied to a diesel engine with mechanical fuel supply; the diesel and methanol dual-fuel engine control system includes: a methanol control computer, an accelerator pedal position sensor, a throttle actuator, a throttle, a diesel nozzle, an electronically controlled throttle and a methanol injector; the methanol control computer obtains a signal from the accelerator pedal position sensor, determines the current load of the engine, and controls the operation of the throttle actuator, the electronically controlled throttle and the methanol injector according to the current load of the engine, so as to match the methanol injection amount with the intake amount; the throttle actuator is connected to the throttle on the diesel pipeline to control the opening of the throttle; the diesel nozzle is arranged at the end of the diesel pipeline to inject diesel into the engine cylinder; the electronically controlled throttle is arranged on the intake pipe to control the intake amount of the engine; the methanol injector is arranged at the end of the methanol pipeline to inject methanol into the intake pipe to form a combustible mixed gas with the air in the intake pipe, and enters the engine cylinder through the intake pipe for combustion.

[0007] Optionally, exhaust gas generated by combustion in the engine cylinder is discharged through an exhaust pipe connected to the engine cylinder, and the diesel and methanol dual-fuel engine control system also includes: a three-way catalytic converter and a muffler; the three-way catalytic converter and the muffler are sequentially arranged on the exhaust pipe, the three-way catalytic converter is used to purify the exhaust gas generated by combustion in the engine cylinder; the muffler is used to reduce the noise generated by the exhaust.

[0008] Optionally, exhaust gas generated by combustion in the engine cylinder is discharged through an exhaust pipe connected to the engine cylinder, and the diesel and methanol dual-fuel engine control system also includes: an oxygen sensor; the oxygen sensor is arranged on the exhaust pipe, and is used to detect the oxygen content in the exhausted exhaust gas; the methanol control computer is connected to the oxygen sensor, and is used to correct the injection pulse width of the methanol injector according to the feedback signal of the oxygen sensor.

[0009] Optionally, the diesel and methanol dual-fuel engine control system also includes: a mode conversion switch; the mode conversion switch is connected to the methanol control computer and is used to control the working mode of the engine; the engine working mode includes a dual-fuel working mode and a single-fuel working mode; the single-fuel working mode is a mode that only uses diesel as fuel to work; the dual-fuel working mode is a mode that uses diesel and methanol as fuel at the same time to work.

[0010] In a second aspect, the present application provides a diesel and methanol dual-fuel engine control method, which is applied to the diesel and methanol dual-fuel engine control system described above. The diesel and methanol dual-fuel engine control method comprises the following steps:

[0011] Determine the current engine load based on the signal from the accelerator pedal position sensor.

[0012] According to the current load of the engine, the operation of the throttle actuator, the electronically controlled throttle valve and the methanol injector is controlled to achieve the matching of the methanol injection amount and the intake amount. The throttle actuator is connected to the throttle on the diesel pipeline to control the throttle opening; the diesel nozzle is arranged at the end of the diesel pipeline to inject diesel into the engine cylinder; the electronically controlled throttle valve is arranged on the intake pipe to control the intake amount of the engine; the methanol injector is arranged at the end of the methanol pipeline to inject methanol into the intake pipe to form a combustible mixed gas with the air in the intake pipe, and enter the engine cylinder through the intake pipe for combustion.

[0013] In a third aspect, the present application provides a diesel and methanol dual-fuel engine control system, which is applied to a diesel engine with electronically controlled fuel supply, and comprises: a methanol control computer, an accelerator pedal position sensor, a diesel control computer, a diesel nozzle, an electronically controlled throttle and a methanol injector; the diesel control computer obtains a signal from the accelerator pedal position sensor, determines the current load of the engine, and preliminarily determines the diesel demand; the methanol control computer obtains a signal from the accelerator pedal position sensor and a signal from the diesel control computer, controls the operation of the diesel nozzle, the electronically controlled throttle and the methanol injector, and achieves matching of the methanol injection amount with the intake amount; the diesel nozzle is arranged at the end of the diesel pipeline, and is used to inject diesel into the engine cylinder; the electronically controlled throttle is arranged on the intake pipe, and is used to control the intake amount of the engine; the methanol injector is arranged at the end of the methanol pipeline, and is used to inject methanol into the intake pipe, and forms a combustible mixed gas with the air in the intake pipe, and enters the engine cylinder through the intake pipe for combustion.

[0014] Optionally, exhaust gas generated by combustion in the engine cylinder is discharged through an exhaust pipe connected to the engine cylinder, and the diesel and methanol dual-fuel engine control system also includes: a three-way catalytic converter and a muffler; the three-way catalytic converter and the muffler are sequentially arranged on the exhaust pipe, the three-way catalytic converter is used to purify the exhaust gas generated by combustion in the engine cylinder; the muffler is used to reduce the noise generated by the exhaust.

[0015] Optionally, exhaust gas generated by combustion in the engine cylinder is discharged through an exhaust pipe connected to the rear of the engine cylinder, and the diesel and methanol dual-fuel engine control system also includes: an oxygen sensor; the oxygen sensor is arranged on the exhaust pipe, and is used to detect the oxygen content in the exhausted exhaust gas; the methanol control computer is connected to the oxygen sensor, and is used to correct the injection pulse width of the methanol injector according to the feedback signal of the oxygen sensor.

[0016] Optionally, the diesel and methanol dual-fuel engine control system also includes: a mode conversion switch; the mode conversion switch is respectively connected to the diesel control computer and the methanol control computer, and is used to control the working mode of the engine; the engine working mode includes a dual-fuel working mode and a single-fuel working mode; the single-fuel working mode is a mode that only uses diesel as fuel to work; the dual-fuel working mode is a mode that uses diesel and methanol as fuel at the same time.

[0017] In a fourth aspect, the present application provides a diesel and methanol dual-fuel engine control method, which is applied to the diesel and methanol dual-fuel engine control system described above. The diesel and methanol dual-fuel engine control method comprises the following steps:

[0018] Based on the signal from the accelerator pedal position sensor, the current engine load is determined and the diesel demand is preliminarily determined.

[0019] According to the signal of the accelerator pedal position sensor and the diesel demand, the operation of the diesel nozzle, the electronically controlled throttle and the methanol injector is controlled to achieve the matching of the methanol injection amount and the intake amount; the diesel nozzle is arranged at the end of the diesel pipeline, and is used to inject diesel into the engine cylinder; the electronically controlled throttle is arranged on the intake pipe, and is used to control the intake amount of the engine; the methanol injector is arranged at the end of the methanol pipeline, and is used to inject methanol into the intake pipe, so as to form a combustible mixed gas with the air in the intake pipe, and enter the engine cylinder through the intake pipe for combustion.

[0020] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0021] The present application provides a diesel and methanol dual-fuel engine control system and method, which can be applied to diesel engines with mechanical or electronically controlled fuel supply. In the control system, the current load of the engine is first determined by the signal of the accelerator pedal position sensor, and the throttle actuator or the diesel nozzle is controlled according to the current load of the engine to adjust the amount of diesel injected into the engine cylinder, and then the operation of the electronically controlled throttle and the methanol injector is controlled to control the intake volume of the engine and the amount of methanol injected into the intake pipe respectively, so as to achieve the matching of the methanol injection volume with the intake volume, form a combustible mixed gas that can be adjusted in quantity and enter the engine cylinder for combustion. The above scheme of the present application changes the original diesel engine load quality adjustment mode to a quantity adjustment mode as the main mode, controls the methanol injection volume to match the intake volume, and uses a small amount of diesel for ignition, so as to achieve the combustion of the theoretical mixed gas of diesel and methanol dual fuels when the engine is working, and improves the reliability of the engine operation. It has important practical significance for alleviating the tension of vehicle fuel supply, improving economic benefits and reducing PM2.5 pollution to the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 A schematic structural diagram of a diesel and methanol dual-fuel engine control system provided in one embodiment of the present application when applied to a diesel engine with mechanical fuel supply.

[0024] Figure 2 A flowchart of a diesel and methanol dual-fuel engine control method provided in one embodiment of the present application.

[0025] Figure 3 A schematic structural diagram of a diesel and methanol dual-fuel engine control system provided in another embodiment of the present application when applied to a diesel engine with electronically controlled fuel supply.

[0026] Figure 4 A flow chart of a diesel and methanol dual-fuel engine control system provided in another embodiment of the present application. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0028] As an automobile fuel, methanol has brought the dawn of energy hope to the automobile industry, and its economic development heralds the rise of an emerging industrial group. The application technology of methanol replacing gasoline in spark-ignition engines has achieved remarkable results. However, the application of methanol in diesel engines faces many challenges. For example, methanol has a higher latent heat of vaporization, a lower cetane number and calorific value, a less wide combustion range than diesel, and methanol is corrosive to metals and has a swelling effect on plastics. Despite this, the driving force behind the research and application of methanol diesel lies in the huge potential of the diesel market. The annual consumption of diesel is about twice that of gasoline. If methanol can successfully replace diesel, it will be of great significance.

[0029] At present, the characteristics of using methanol fuel in diesel engines are: keeping the original diesel engine structure unchanged, by adding a methanol single-point injection system, the diesel engine can adapt to the dual-fuel combustion of diesel and methanol. At startup, small load and large load conditions, the diesel engine mainly uses diesel as fuel; at medium load conditions, it switches to the dual-fuel mode of diesel and methanol, the ignition method uses diesel ignition, and the load regulation adopts the mass regulation method.

[0030] However, the above existing technologies face a series of challenges. These problems include but are not limited to: the ignition range of the two fuels does not match, resulting in reduced engine performance; in addition, as the proportion of methanol increases, the cetane number may decrease, resulting in difficulty in ignition or misfire in the diesel engine, and because the compression ratio of methanol is higher than that of diesel, it will also cause the compression ratio to increase. In addition, from the perspective of environmental pollution, when methanol and diesel are burned in a lean mixture state, the pollutants emitted may not only not decrease, but may increase significantly.

[0031] To sum up, in response to the problems faced by traditional diesel engines when using diesel and methanol dual fuels, this application proposes an improved diesel injection engine control system that can adapt to the operation of diesel and methanol dual fuels. It has important practical significance for alleviating the tight supply of vehicle fuel, improving economic benefits and reducing PM2.5 pollution to the environment.

[0032] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0033] In an exemplary embodiment of the present application, the present application provides a diesel and methanol dual-fuel engine control system, which is applied to a diesel engine with mechanical fuel supply; Figure 1 As shown, the diesel and methanol dual-fuel engine control system includes: a methanol control computer 1-1, an accelerator pedal position sensor 1-2, a throttle actuator 1-3, an accelerator 1-4, a diesel nozzle 1-5, an electronically controlled throttle 1-6 and a methanol injector 1-7; the methanol control computer 1-1 obtains a signal from the accelerator pedal position sensor 1-2, determines the current load of the engine, and controls the operation of the throttle actuator 1-3, the electronically controlled throttle 1-6 and the methanol injector 1-7 according to the current load of the engine, so as to achieve matching of the methanol injection amount with the intake amount; the throttle actuator 1- 3 is connected to the throttle 1-4 on the diesel pipeline and is used to control the opening of the throttle 1-4; the diesel nozzle 1-5 is arranged at the end of the diesel pipeline and is used to inject diesel into the engine cylinder 1-8; the electronically controlled throttle 1-6 is arranged on the intake pipe 1-9 and is used to control the intake amount of the engine; the methanol injector 1-7 is arranged at the end of the methanol pipeline and is used to inject methanol into the intake pipe 1-9 to form a combustible mixed gas with the air in the intake pipe, and enter the engine cylinder 1-8 through the intake pipe 1-9 for combustion, and output power through the piston 1-10.

[0034] The methanol control computer 1-1 instructs the electronically controlled throttle 1-6 to control the intake air volume entering the engine, so that the methanol injection volume matches the intake air volume, and the load regulation mode of the diesel engine is changed from quality regulation to quantity regulation when burning dual fuels. The methanol control computer 1-1 controls the injection volume of methanol, the throttle actuator 1-3 and the diesel nozzle 1-5 control the injection volume of diesel, and the electronically controlled throttle 1-6 controls the intake volume of air, so as to achieve the control of the air-fuel ratio λ=1.00±0.03, which is the theoretical combustion mixture ratio when using dual fuels. In the dual fuel working mode, the maximum combustion temperature of the diesel engine is controlled, the engine does not have sudden explosion phenomenon during operation, and the reliability of the engine operation is improved. The diesel replacement rate exceeds 70%, and the fuel cost is saved by more than 50%. The conventional emission, smoke density and PM2.5 emission of the engine are greatly reduced.

[0035] As an improved method, the exhaust gas generated by combustion in the engine cylinder 1-8 is discharged through the exhaust pipe 1-11 connected to the engine cylinder 1-8, and the diesel and methanol dual-fuel engine control system also includes: an oxygen sensor 1-12; the oxygen sensor 1-12 is arranged on the exhaust pipe 1-11, and is used to detect the oxygen content in the exhaust gas; the methanol control computer 1-1 is connected to the oxygen sensor 1-12, and is used to correct the injection pulse width of the methanol injector 1-7 according to the feedback signal of the oxygen sensor 1-12. In this way, the methanol injection controlled by the methanol computer and the introduction of the signal of the oxygen sensor 1-12 realize the methanol multi-point closed-loop control.

[0036] In a further defined embodiment, the diesel and methanol dual-fuel engine control system also includes: a three-way catalytic converter 1-13 and a muffler 1-14; the three-way catalytic converter 1-13 and the muffler 1-14 are sequentially arranged on the exhaust pipe 1-11, the three-way catalytic converter 1-13 is used to purify the exhaust gas generated by combustion in the engine cylinder 1-8, and the three-way catalytic converter 1-13 can effectively treat CO, HC, and NOX in the exhaust gas generated by combustion; the muffler 1-14 is used to reduce the noise generated by the exhaust.

[0037] As an additional limitation, the diesel and methanol dual-fuel engine control system also includes: a mode conversion switch 1-15; the mode conversion switch 1-15 is connected to the methanol control computer 1-1 and is used to control the working mode of the engine; the working mode of the engine includes a dual-fuel working mode and a single-fuel working mode; the single-fuel working mode is a mode that uses only diesel as fuel to work; the dual-fuel working mode is a mode that uses diesel and methanol as fuel at the same time. That is, after installing the control system, the diesel engine can work with a single diesel fuel or with a dual fuel of diesel and methanol, and the two working modes can be quickly switched.

[0038] Based on the same inventive concept, the embodiment of the present application also provides a method for applying to the diesel and methanol dual-fuel engine control system involved above, such as Figure 2 As shown, the diesel and methanol dual-fuel engine control method includes the following steps:

[0039] A1. Determine the current engine load based on the signal from the accelerator pedal position sensor 1-2.

[0040] A2. According to the current load of the engine, the operation of the throttle actuator 1-3, the electronically controlled throttle valve 1-6 and the methanol injector 1-7 is controlled to match the methanol injection amount with the intake amount. The throttle actuator 1-3 is connected to the throttle 1-4 on the diesel pipeline to control the opening of the throttle 1-4; the diesel nozzle 1-5 is arranged at the end of the diesel pipeline to inject diesel into the engine cylinder 1-8; the electronically controlled throttle valve 1-6 is arranged on the intake pipe 1-9 to control the intake amount of the engine; the methanol injector 1-7 is arranged at the end of the methanol pipeline to inject methanol into the intake pipe 1-9 to form a combustible mixed gas with the air in the intake pipe, and enter the engine cylinder 1-8 through the intake pipe 1-9 for combustion, and output power through the piston 1-10.

[0041] As a specific explanation, for the diesel and methanol dual-fuel engine control system and method for the above-mentioned diesel engine with mechanical fuel supply, the system control process from the start-up to the shutdown of the diesel engine is described below, mainly including the start-up stage, the idle holding stage, the idle-10% load stage, the 10% load-90% load stage, the 90% load-95% load stage, the 95% load-full load stage and the full load slowly reduced to the idle stage until shutdown.

[0042] During the startup phase, the mode conversion switch 1-15 is placed in the dual-fuel working mode, the methanol control computer 1-1 obtains the signal of the accelerator pedal position sensor 1-2, sends a command to control the electronic throttle 1-6 to be fully opened, and sends a command to control the methanol injector 1-7 not to work, and then sends a command to the throttle actuator 1-3 to control the throttle 1-4 to move, and the diesel enters the engine cylinder 1-8 through the diesel pipeline and the diesel nozzle 1-5 to burn, and the engine starts in full diesel mode and enters the idle holding stage.

[0043] During the idle holding stage, the electronic throttle valve 1-6 remains fully open, the methanol control computer 1-1 does not send any instructions to the methanol injector 1-7, and methanol is not injected into the system; the signal of the accelerator pedal position sensor 1-2 is obtained, and the methanol control computer 1-1 and the throttle actuator 1-3 control the throttle 1-4 to open so that diesel is injected into the engine, and the engine remains in an idle state.

[0044] In the idle-10% load stage, the accelerator pedal position sensor 1-2 is depressed, and the load increases from 0% to 10%; the methanol control computer 1-1 receives the signal from the accelerator pedal position sensor 1-2, and sends a signal to the electronic throttle 1-6 to control the electronic throttle 1-6 to transition from full opening at idle to minimum opening; the methanol control computer 1-1 receives the signal from the accelerator pedal position sensor 1-2, opens the methanol injector 1-7 according to the set pulse, and receives the signal fed back by the oxygen sensor 1-12 to correct its pulse width, and the λ value at the 10% load point transitions to 1.00±0.03, and the diesel is supplied according to the original diesel engine fuel supply characteristics. Within this load range, the diesel supply increases, and the methanol supply increases with the increase of load.

[0045] In the 10% load-90% load stage, the accelerator pedal position sensor 1-2 is depressed, and the load increases from 10% to 90%; the methanol control computer 1-1 receives the signal from the accelerator pedal position sensor 1-2, and sends a signal to the electronic throttle 1-6 to control the electronic throttle 1-6 to open from 10% to 90%; the methanol control computer 1-1 and the throttle actuator 1-3 manipulate the throttle 1-4 to keep the diesel fuel supply at 10% load unchanged; the methanol control computer 1-1 obtains the signal from the accelerator pedal position sensor 1-2, and the methanol injector 1-7 injects methanol according to the set pulse instruction, and receives the feedback signal from the oxygen sensor 1-12 to correct the pulse width. During the process, the injection amount of methanol increases, maintaining λ=1.00±0.03.

[0046] In the 90% load-95% load stage, the accelerator pedal position sensor 1-2 is depressed, and the load increases from 90% to 95%; the methanol control computer 1-1 obtains the signal of the accelerator pedal position sensor 1-2, and sends a signal to the electronic throttle 1-6 to control the electronic throttle 1-6 to open from 90% to 95%; the methanol control computer 1-1 and the throttle actuator 1-3 control the throttle 1-4 to rapidly increase the diesel supply from the supply at 10% load to the supply at 95% load, and within this load range, the diesel supply increases; then, the methanol injection amount is reduced to 5% (or stopped completely) according to the set pulse, the methanol control computer 1-1 no longer corrects the injection pulse, the λ value increases, and the methanol supply decreases rapidly as the load increases.

[0047] In the 95% load-full load stage, the accelerator pedal position sensor 1-2 is depressed, and the load increases from 95% to full load; the methanol control computer 1-1 obtains the signal of the accelerator pedal position sensor 1-2, and sends a signal to the electronic throttle 1-6 to control the electronic throttle 1-6 to open from 95% to full opening; the methanol control computer 1-1 controls the diesel supply through the throttle actuator 1-3 according to the original engine fuel supply characteristics from 95% to 100%, and the diesel supply increases within this load range; then, the methanol injection is maintained at the methanol injection amount at 5% load or stopped altogether according to the setting, the methanol control computer 1-1 no longer corrects the injection pulse width, and the methanol supply stops.

[0048] During the load reduction process from full load to idle stage, the control system returns to idle state according to the control route of the original load increase process until shutdown.

[0049] In another exemplary embodiment of the present application, the present application provides a diesel and methanol dual-fuel engine control system, which is applied to a diesel engine with electronically controlled fuel supply, such as Figure 3 As shown, the diesel and methanol dual-fuel engine control system includes: a methanol control computer 2-1, an accelerator pedal position sensor 2-2, a diesel control computer 2-3, a diesel nozzle 2-4, an electronically controlled throttle 2-5 and a methanol injector 2-6; the diesel control computer 2-3 obtains a signal from the accelerator pedal position sensor 2-2, determines the current load of the engine, and preliminarily determines the diesel demand; the methanol control computer 2-1 obtains a signal from the accelerator pedal position sensor 2-2 and a signal from the diesel control computer 2-3, controls the diesel nozzle 2-4, the electronically controlled throttle 2-5 and the methanol injector 2-6 5 and the methanol injector 2-6 work to achieve the matching of the methanol injection amount and the intake amount; the diesel nozzle 2-4 is arranged at the end of the diesel pipeline, and is used to inject diesel into the engine cylinder 2-7; the electronic throttle 2-5 is arranged on the intake pipe 2-8, and is used to control the intake amount of the engine; the methanol injector 2-6 is arranged at the end of the methanol pipeline, and is used to inject methanol into the intake pipe 2-8, and form a combustible mixed gas with the air in the intake pipe, and enter the engine cylinder 2-7 through the intake pipe 2-8 for combustion, and output power through the piston 2-9.

[0050] As an improved method, the exhaust gas generated by the combustion in the engine cylinder 2-7 is discharged through the exhaust pipe 2-10 connected to the engine cylinder 2-7, and the exhaust gas generated by the combustion in the engine cylinder 2-7 is discharged through the exhaust pipe 2-10 connected to the rear of the engine cylinder 2-7. The diesel and methanol dual-fuel engine control system also includes: an oxygen sensor 2-11; the oxygen sensor 2-11 is arranged on the exhaust pipe 2-10, and is used to detect the oxygen content in the exhaust gas; the methanol control computer 2-1 is connected to the oxygen sensor 2-11, and is used to correct the injection pulse width of the methanol injector 2-6 according to the feedback signal of the oxygen sensor 2-11.

[0051] In a further defined embodiment, the diesel and methanol dual-fuel engine control system also includes: a three-way catalytic converter 2-12 and a muffler 2-13; the three-way catalytic converter 2-12 and the muffler 2-13 are sequentially arranged on the exhaust pipe 2-10, the three-way catalytic converter 2-12 is used to purify the exhaust gas generated by the combustion in the engine cylinder 2-7; the muffler 2-13 is used to reduce the noise generated by the exhaust.

[0052] As an additional limitation, the diesel and methanol dual-fuel engine control system also includes: a mode conversion switch 2-14; the mode conversion switch 2-14 is respectively connected to the diesel control computer 2-3 and the methanol control computer 2-1, and is used to control the engine's operating mode; the engine's operating mode includes a dual-fuel operating mode and a single-fuel operating mode; the single-fuel operating mode is a mode that only uses diesel as fuel for operation; the dual-fuel operating mode is a mode that uses diesel and methanol as fuel at the same time.

[0053] Based on the same inventive concept, the embodiment of the present application also provides a method for applying to the diesel and methanol dual-fuel engine control system involved above, such as Figure 4 As shown, the diesel and methanol dual-fuel engine control method includes the following steps:

[0054] B1. According to the signal of the accelerator pedal position sensor 2-2, the current load of the engine is determined, and the diesel demand is preliminarily determined.

[0055] B2. According to the signal of the accelerator pedal position sensor 2-2 and the diesel demand, the operation of the diesel nozzle 2-4, the electronically controlled throttle 2-5 and the methanol injector 2-6 is controlled to achieve matching of the methanol injection amount with the intake amount; the diesel nozzle 2-4 is arranged at the end of the diesel pipeline, and is used to inject diesel into the engine cylinder 2-7; the electronically controlled throttle 2-5 is arranged on the intake pipe 2-8, and is used to control the intake amount of the engine; the methanol injector 2-6 is arranged at the end of the methanol pipeline, and is used to inject methanol into the intake pipe 2-8, and form a combustible mixed gas with the air in the intake pipe, and enter the engine cylinder 2-7 through the intake pipe 2-8 for combustion, and output power through the piston 2-9.

[0056] As a specific explanation, for the diesel and methanol dual-fuel engine control system and method for the above-mentioned diesel engine with electronically controlled fuel supply, the system control process from the start-up to the shutdown of the diesel engine is described below, mainly including the start-up stage, the idle holding stage, the idle-10% load stage, the 10% load-90% load stage, the 90% load-95% load stage, the 95% load-full load stage and the full load slowly reduced to the idle stage until shutdown.

[0057] During the startup phase, the mode conversion switch 2-14 is placed in the dual-fuel working mode, the diesel control computer 2-3 obtains the signal from the accelerator pedal position sensor 2-2, the methanol control computer 2-1 sends a command to control the electronic throttle 2-5 to be fully opened, and sends a command to control the methanol injector 2-6 not to work, and then sends a command to the diesel nozzle 2-4 to work, the diesel enters the engine cylinder 2-7 through the diesel pipeline and the diesel nozzle 2-4 to burn, the engine starts in full diesel mode and enters the idle holding phase.

[0058] During the idle holding stage, the electronic throttle valve 2-5 remains fully open, the methanol control computer 2-1 does not send a working instruction to the methanol injector 2-6, and methanol is not injected into the system; the accelerator pedal position sensor 2-2 signal is obtained, the diesel control computer 2-3 and the methanol control computer 2-1 control the diesel nozzle 2-4 to work, diesel is injected into the engine, and the engine remains in idle state.

[0059] In the idle-10% load stage, the accelerator pedal position sensor 2-2 is depressed, and the load increases from 0% to 10%; the methanol control computer 2-1 obtains the signal of the accelerator pedal position sensor 2-2, and sends a signal to the electronic throttle 2-5 to control the electronic throttle 2-5 to transition from full opening at idle to minimum opening; the methanol control computer 2-1 obtains the signal of the accelerator pedal position sensor 2-2, opens the methanol injector 2-6 according to the set pulse, and receives the signal fed back by the oxygen sensor 2-11 to correct its pulse width, and the 10% load point λ value transitions to 1.00±0.03, and diesel is supplied according to the original diesel engine fuel supply characteristics. Within this load range, the diesel supply increases, and the methanol supply increases with the increase of load.

[0060] In the 10% load-90% load stage, the accelerator pedal position sensor 2-2 is depressed, and the load increases from 10% to 90%; the methanol control computer 2-1 receives the signal from the accelerator pedal position sensor 2-2, and sends a signal to the electronic throttle 2-5 to control the electronic throttle 2-5 to open from 10% to 90%; the methanol control computer 2-1 and the diesel control computer 2-3 control the diesel nozzle 2-4 to keep the diesel fuel supply at 10% load unchanged; the methanol control computer 2-1 obtains the signal from the accelerator pedal position sensor 2-2, controls the methanol injector 2-6 to inject methanol according to the set pulse command, and receives the feedback signal from the oxygen sensor 2-11 to correct the pulse width. During the process, the injection amount of methanol increases, maintaining λ=1.00±0.03.

[0061] In the 90% load-95% load stage, the accelerator pedal position sensor 2-2 is depressed, and the load increases from 90% to 95%; the methanol control computer 2-1 obtains the signal of the accelerator pedal position sensor 2-2, and sends a signal to the electronic throttle 2-5 to control the electronic throttle 2-5 to open from 90% to 95%; the methanol control computer 2-1 and the diesel control computer 2-3 control the diesel nozzle 2-4 to rapidly increase the diesel supply from the supply at 10% load to the supply at 95% load, and within this load range, the diesel supply increases; then, the methanol injection amount is reduced to 5% (or stopped completely) according to the set pulse, the methanol control computer 2-1 no longer corrects the injection pulse, the λ value increases, and the methanol supply decreases rapidly as the load increases.

[0062] In the 95% load-full load stage, the accelerator pedal position sensor 2-2 is depressed, and the load increases from 95% to full load; the methanol control computer 2-1 obtains the signal of the accelerator pedal position sensor 2-2, and sends a signal to the electronic throttle 2-5 to control the electronic throttle 2-5 to open from 95% to full opening; the diesel control computer 2-3 controls the supply amount of the diesel nozzle 2-4 through the methanol control computer 2-1 according to the original engine fuel supply characteristics from 95% to 100%, and the diesel fuel supply increases within this load range; then, the methanol injection is maintained at the methanol injection amount at 5% load or stopped altogether according to the setting, the methanol control computer 2-1 no longer corrects the injection pulse width, and the methanol supply is stopped.

[0063] During the load reduction process from full load to idle stage, the control system returns to idle state according to the control route of the original load increase process until shutdown.

[0064] The average proportion of methanol replacing diesel in this control system is about 70%. Considering the improved combustion efficiency of methanol oxygenated fuel, the calculated ratio of methanol to diesel calorific value is 2.0:1. Taking Shaanxi Automobile Delong F3000 as an example, the fuel consumption per 100 kilometers is 35L. The recent methanol price is 2.0 yuan / liter and the diesel price is 6.01 yuan / liter. After installing the control system of this application, the diesel cost is 161.2 yuan per 100 kilometers. If diesel is used alone, the cost per 100 kilometers is 210 yuan. The cost per 100 kilometers of using a dual-fuel control system is nearly 48.8 yuan cheaper than the cost of using diesel alone. If you travel 600 kilometers a day, you can save about 300 yuan in fuel costs every day.

[0065] The above scheme of the present application changes the original quality regulation mode of the diesel engine load to a mainly quantity regulation mode, controls the methanol injection amount to match the intake amount, and uses a small amount of diesel for ignition, thereby realizing the theoretical mixture combustion of diesel and methanol dual fuels when the engine is working, and maintaining the air-fuel ratio λ within the range of 1.00±0.03. The working characteristics of the diesel engine meet the relevant requirements of the national standard, and also control the maximum combustion temperature of the diesel engine. The engine does not explode during operation, thereby improving the reliability of the engine operation. It has important practical significance for alleviating the tension in the supply of vehicle fuel, improving economic benefits, and reducing PM2.5 pollution to the environment.

[0066] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0067] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A diesel and methanol dual-fuel engine control system, characterized in that: The diesel and methanol dual-fuel engine control system is applied to a diesel engine with mechanical fuel supply; The diesel and methanol dual-fuel engine control system includes: a methanol control computer, an accelerator pedal position sensor, a throttle actuator, a throttle, a diesel nozzle, an electronically controlled throttle and a methanol injector; The methanol control computer obtains the signal of the accelerator pedal position sensor, determines the current load of the engine, and controls the operation of the throttle actuator, the electronically controlled throttle valve and the methanol injector according to the current load of the engine, so as to match the methanol injection amount with the intake amount; the throttle actuator is connected to the throttle on the diesel pipeline to control the throttle opening; the diesel nozzle is arranged at the end of the diesel pipeline to inject diesel into the engine cylinder; the electronically controlled throttle valve is arranged on the intake pipe to control the intake amount of the engine; the methanol injector is arranged at the end of the methanol pipeline to inject methanol into the intake pipe to form a combustible mixed gas with the air in the intake pipe, and enters the engine cylinder through the intake pipe for combustion.

2. The diesel and methanol dual-fuel engine control system according to claim 1, characterized in that: The exhaust gas generated by combustion in the engine cylinder is discharged through an exhaust pipe connected to the engine cylinder. The diesel and methanol dual-fuel engine control system also includes: a three-way catalytic converter and a muffler; the three-way catalytic converter and the muffler are sequentially arranged on the exhaust pipe, the three-way catalytic converter is used to purify the exhaust gas generated by combustion in the engine cylinder; the muffler is used to reduce the noise generated by the exhaust.

3. The diesel and methanol dual-fuel engine control system according to claim 1, characterized in that: The exhaust gas generated by combustion in the engine cylinder is discharged through an exhaust pipe connected to the rear of the engine cylinder. The diesel and methanol dual-fuel engine control system also includes: an oxygen sensor; the oxygen sensor is arranged on the exhaust pipe, and is used to detect the oxygen content in the exhausted exhaust gas; the methanol control computer is connected to the oxygen sensor, and is used to correct the injection pulse width of the methanol injector according to the feedback signal of the oxygen sensor.

4. The diesel and methanol dual-fuel engine control system according to claim 1, characterized in that: The diesel and methanol dual-fuel engine control system also includes: a mode conversion switch; the mode conversion switch is connected to the methanol control computer and is used to control the working mode of the engine; the working mode of the engine includes a dual-fuel working mode and a single-fuel working mode; the single-fuel working mode is a mode in which only diesel is used as fuel for working; the dual-fuel working mode is a mode in which diesel and methanol are used as fuels at the same time for working.

5. A diesel and methanol dual-fuel engine control method, characterized in that: Applied to the diesel and methanol dual-fuel engine control system according to any one of claims 1 to 4, the diesel and methanol dual-fuel engine control method comprises: Determine the current engine load based on the signal of the accelerator pedal position sensor; According to the current load of the engine, the operation of the throttle actuator, the electronically controlled throttle valve and the methanol injector is controlled to achieve matching of the methanol injection amount with the intake amount; the throttle actuator is connected to the throttle on the diesel pipeline to control the throttle opening; the diesel nozzle is arranged at the end of the diesel pipeline to inject diesel into the engine cylinder; the electronically controlled throttle valve is arranged on the intake pipe to control the intake amount of the engine; the methanol injector is arranged at the end of the methanol pipeline to inject methanol into the intake pipe to form a combustible mixed gas with the air in the intake pipe, and enter the engine cylinder through the intake pipe for combustion.

6. A diesel and methanol dual-fuel engine control system, characterized in that: The diesel and methanol dual-fuel engine control system is applied to a diesel engine with electronically controlled fuel supply, and the diesel and methanol dual-fuel engine control system includes: a methanol control computer, an accelerator pedal position sensor, a diesel control computer, a diesel nozzle, an electronically controlled throttle and a methanol injector; the diesel control computer obtains a signal from the accelerator pedal position sensor, determines the current load of the engine, and preliminarily determines the diesel demand; the methanol control computer obtains a signal from the accelerator pedal position sensor and a signal from the diesel control computer, controls the operation of the diesel nozzle, the electronically controlled throttle and the methanol injector, and achieves matching of the methanol injection amount with the intake amount; the diesel nozzle is arranged at the end of the diesel pipeline, and is used to inject diesel into the engine cylinder; the electronically controlled throttle is arranged on the intake pipe, and is used to control the intake amount of the engine; the methanol injector is arranged at the end of the methanol pipeline, and is used to inject methanol into the intake pipe, and forms a combustible mixed gas with the air in the intake pipe, and enters the engine cylinder through the intake pipe for combustion.

7. The diesel and methanol dual-fuel engine control system according to claim 6, characterized in that: The exhaust gas generated by combustion in the engine cylinder is discharged through an exhaust pipe connected to the engine cylinder. The diesel and methanol dual-fuel engine control system also includes: a three-way catalytic converter and a muffler; the three-way catalytic converter and the muffler are sequentially arranged on the exhaust pipe, the three-way catalytic converter is used to purify the exhaust gas generated by combustion in the engine cylinder; the muffler is used to reduce the noise generated by the exhaust.

8. The diesel and methanol dual-fuel engine control system according to claim 6, characterized in that: The exhaust gas generated by combustion in the engine cylinder is discharged through an exhaust pipe connected to the rear of the engine cylinder. The diesel and methanol dual-fuel engine control system also includes: an oxygen sensor; the oxygen sensor is arranged on the exhaust pipe, and is used to detect the oxygen content in the exhausted exhaust gas; the methanol control computer is connected to the oxygen sensor, and is used to correct the injection pulse width of the methanol injector according to the feedback signal of the oxygen sensor.

9. The diesel and methanol dual-fuel engine control system according to claim 6, characterized in that: The diesel and methanol dual-fuel engine control system also includes: a mode conversion switch; the mode conversion switch is connected to the diesel control computer and the methanol control computer respectively, and is used to control the working mode of the engine; the working mode of the engine includes a dual-fuel working mode and a single-fuel working mode; the single-fuel working mode is a mode in which only diesel is used as fuel for working; the dual-fuel working mode is a mode in which diesel and methanol are used as fuels at the same time for working.

10. A diesel and methanol dual-fuel engine control method, characterized in that: Applied to the diesel and methanol dual-fuel engine control system according to any one of claims 6 to 9, the diesel and methanol dual-fuel engine control method comprises: According to the signal of the accelerator pedal position sensor, the current load of the engine is determined, and the diesel demand is preliminarily determined; According to the signal of the accelerator pedal position sensor and the diesel demand, the operation of the diesel nozzle, the electronically controlled throttle and the methanol injector is controlled to achieve the matching of the methanol injection amount and the intake amount; the diesel nozzle is arranged at the end of the diesel pipeline, and is used to inject diesel into the engine cylinder; the electronically controlled throttle is arranged on the intake pipe, and is used to control the intake amount of the engine; the methanol injector is arranged at the end of the methanol pipeline, and is used to inject methanol into the intake pipe, so as to form a combustible mixed gas with the air in the intake pipe, and enter the engine cylinder through the intake pipe for combustion.

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