Methanol-diesel dual-fuel control system for diesel vehicle in use

Abstract

The invention discloses a methanol-diesel dual-fuel control system for an in-use diesel vehicle, which belongs to the technical field of diesel fuel control and comprises an engine controller and a methanol / diesel dual-fuel controller. According to the methanol / diesel oil dual-fuel controller, when an engine works in a dual-fuel mode, a methanol pump is started to achieve Peakamp; a methanol nozzle is driven to spray methanol in a Hold mode, and when the number of cycles reaches a calibration value, a mode switching relay is started in a Peakamp mode; oil sprayers of all cylinders are driven in a Hold mode; and the methanol / diesel oil dual-fuel controller is communicated with the data monitoring and mode switching module and the parameter calibration module through a CAN (Controller Area Network). By the adoption of the methanol-diesel dual-fuel control system for the in-use diesel vehicle, the injection phase of the ignited diesel and the fuel injection amount of the ignited diesel can be accurately controlled according to requirements, the high diesel substitution rate is achieved, and therefore the good dynamic property and economical efficiency are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of diesel engine fuel control, in particular to a methanol-diesel dual-fuel control system for an in-use diesel vehicle. Background Art

[0002] Diesel engines have the advantages of high compression ratio, good adaptability, and high thermal efficiency. They are the main power source in the fields of agriculture, transportation, etc. However, pollutants such as NOx, HC, and PM generated by diesel engines during operation will cause air pollution. Since 2019, my country's dependence on foreign oil has exceeded 70%. In order to reduce dependence on oil resources, my country has launched the promotion of the application of methanol as a clean alternative fuel. Methanol has the characteristics of high oxygen content, wide sources, and low prices. Diesel engines are the main power source of high-power power machinery in my country. The blending of methanol in diesel engines is of great significance for effectively reducing emissions, reducing dependence on oil, and protecting the environment.

[0003] When the diesel engine in diesel vehicles currently uses methanol-diesel dual-fuel combustion, the ignition fuel injection amount cannot be accurately controlled, the ignition diesel injection phase cannot be accurately controlled, the diesel substitution rate is not high, and good power and economy cannot be achieved. Summary of the invention

[0004] The purpose of the present invention is to provide a methanol-diesel dual-fuel control system for diesel vehicles in use, which can accurately control the ignition diesel injection phase and the ignition fuel injection amount according to needs, thereby achieving a higher substitution rate, better power and economy.

[0005] To achieve the above-mentioned object, the present invention provides a methanol-diesel dual-fuel control system for an in-use diesel vehicle, comprising an engine controller, a methanol / diesel dual-fuel controller, a data monitoring and mode switching module, a parameter calibration module, a simulated load and cooling device, a knock detection module, an oxygen concentration detection module, a methanol pump and injection module, and a remote liquid level intelligent monitoring module. The methanol / diesel dual-fuel controller receives a mode switching signal, an engine crankshaft position sensor signal, an engine intake pressure / temperature sensor signal, an engine coolant temperature sensor signal, an engine common rail pressure sensor signal, a knock sensor signal, and an oxygen sensor signal through a T15 signal line; When the engine is in the diesel / methanol dual-fuel working mode, the methanol / diesel dual-fuel controller starts the methanol pump and drives the methanol nozzle to spray methanol in the Peak & Hold mode. The methanol nozzle is located at the connection between the engine intake pipe and the engine body. When the number of cycles reaches the calibration value, the mode switching relay is turned on to drive the injectors of each cylinder in the Peak & Hold mode. The methanol / diesel dual-fuel controller communicates with the data monitoring and mode switching module and the parameter calibration module through CAN. The system has a built-in analog crankshaft signal that is synchronized with the engine crankshaft position sensor signal and has an accuracy of 0.1 degree crankshaft angle.

[0006] Preferably, the methanol / diesel dual-fuel controller calculates the engine speed, the missing teeth of the crankshaft position signal, the tooth number of each tooth in an engine working cycle, the phase of each injection pulse signal of each cylinder and the total injection pulse width of each cylinder through the engine crankshaft position sensor signal and the first cylinder injection signal; and calculates the total injection amount of each cylinder according to the engine common rail pressure sensor signal, the injector characteristics and the total injection pulse width of each cylinder per cycle, and corrects the injection amount according to the oxygen sensor signal.

[0007] Preferably, the engine controller determines whether the engine is in a pure diesel operating mode or a diesel / methanol dual-fuel operating mode according to a mode switching signal.

[0008] Preferably, when the engine is in pure diesel operation mode, the mode switching relay is not turned on, and the engine ECU directly drives the injector.

[0009] Preferably, when the engine is in the diesel / methanol dual-fuel working mode, the engine dual-fuel controller drives the injector to inject diesel, determines the injection amount of each cylinder in each cycle according to the oxygen sensor signal and the calibrated control parameters, injects at the main injection phase of the previous cycle, and adjusts the injection phase according to the knock sensor signal and the calibration parameters; at the same time, it communicates with the parameter calibration module and the data monitoring module in real time; when the engine is in the diesel / methanol dual-fuel working mode, the injector is driven by the same Peak&Hold driving method and the same driving voltage and current parameters as the original engine ECU.

[0010] Preferably, the data monitoring and mode switching module is installed in the cab. The data monitoring module is used for the driver to monitor the system's water temperature, engine speed, methanol tank liquid level, methanol injection pressure, methanol injection pulse width and fault codes; the mode switching module is integrated in the data monitoring module, and the pure diesel and diesel / methanol dual-fuel operating modes are manually switched by touching the buttons.

[0011] Preferably, when the engine is in diesel / methanol dual-fuel operating mode, the knock sensor signal, oxygen concentration signal, engine power and substitution rate parameters are used as constraints, and the parameter calibration module calibrates the diesel injection amount, diesel injection timing, methanol injection amount and methanol injection timing under all operating conditions.

[0012] Preferably, when the engine is in diesel / methanol dual-fuel operation mode, a fuel injector of the same model as the engine is used as a simulated load, the engine ECU drives the simulated load, isolation technology is used between each drive circuit, and the fuel injector drive circuit forms a closed loop.

[0013] Preferably, a cooling device is provided at the simulated load, and the cooling device is connected in series to the methanol supply system, and its cooling method adopts oil cooling, wherein methanol is used as the cooling medium.

[0014] Therefore, the present invention adopts the above-mentioned methanol-diesel dual-fuel control system for diesel vehicles in use. When the engine is in the diesel / methanol dual-fuel working mode, diesel injection is used for ignition. The amount of ignited diesel is obtained based on the total injection amount, replacement rate and correction coefficient of multiple injections such as pre-injection, main injection and post-injection in the previous cycle. The injection amount takes into account both power and economy. It is injected at the phase of the main injection in the previous cycle. At the same time, the injection phase is corrected according to the engine power and the knock sensor signal.

[0015] The system has a built-in analog crankshaft signal that is synchronized with the engine crankshaft position sensor signal and has an accuracy of 0.1 degree crankshaft angle. Based on this signal, the ignition diesel injection phase can be accurately controlled. At the same time, when the system is in dual-fuel mode, the diesel / methanol dual-fuel controller takes over the injection and directly drives the injector to control the injection amount and injection timing. This technology is not available in commercial control systems on the market.

[0016] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The present invention is a working principle diagram of an embodiment of a methanol-diesel dual-fuel control system for a diesel vehicle in use. DETAILED DESCRIPTION

[0018] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0019] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by one having ordinary skills in the field to which the present invention belongs.

[0020] Embodiment 1 The present invention provides a methanol-diesel dual-fuel control system for an in-use diesel vehicle. The control system comprises an engine controller, a methanol / diesel dual-fuel controller, a data monitoring and mode switching module, a parameter calibration module, a knock detection module, an oxygen concentration detection module, a simulated load and a cooling device, a methanol pump and an injection module, and a remote liquid level intelligent monitoring module. The methanol / diesel dual-fuel controller receives a mode switching signal, an engine crankshaft position sensor signal, an engine intake pressure / temperature sensor signal, an engine coolant temperature sensor signal, an engine common rail pressure sensor signal, a knock sensor signal, and an oxygen sensor signal through a T15 signal line.

[0021] When the engine is in diesel / methanol dual-fuel working mode, the methanol / diesel dual-fuel controller starts the methanol pump and drives the methanol nozzle to spray methanol in Peak & Hold mode. When the number of cycles reaches the calibration value (the calibration value of different engines is different, and the corresponding calibration value needs to be determined according to the engine model used, generally 3 or 5), the mode switching relay is turned on and drives the injectors of each cylinder in Peak & Hold mode; the methanol / diesel dual-fuel controller communicates with the data monitoring and mode switching module and the parameter calibration module through CAN to realize data transmission between different modules.

[0022] The system has a built-in analog crankshaft signal that is synchronized with the engine crankshaft position sensor signal and has an accuracy of 0.1 degree crankshaft angle. It can advance or delay the injection at the main injection phase of the previous cycle. Based on this signal, the ignition diesel injection timing can be accurately controlled according to the calibrated injection timing parameters.

[0023] The methanol / diesel dual-fuel controller calculates the engine speed, the missing teeth of the crankshaft position signal, the tooth number of each tooth in an engine working cycle, the phase of each injection pulse signal of each cylinder and the total injection pulse width of each cylinder through the engine crankshaft position sensor signal and the first cylinder injection signal; and calculates the total injection amount of each cylinder based on the engine common rail pressure sensor signal, injector characteristics and the total injection pulse width of each cylinder in each cycle.

[0024] The methanol / diesel dual-fuel controller determines whether the engine is in pure diesel working mode or methanol / diesel dual-fuel working mode according to the mode switching signal.

[0025] When the engine is in pure diesel working mode, the mode switching relay is not turned on and the engine ECU directly drives the injector.

[0026] When the engine is in methanol / diesel dual-fuel working mode, the engine dual-fuel controller drives the injector to inject diesel, determines the injection amount of each cylinder in each cycle according to the oxygen sensor signal and calibrated control parameters, injects at the main injection phase of the previous cycle, and adjusts the injection phase according to the knock sensor signal and calibration parameters; at the same time, it communicates with the parameter calibration module and the data monitoring module in real time; when the engine is in dual-fuel working mode, the injector is driven by the same Peak&Hold driving method and the same driving voltage and current parameters as the original engine ECU.

[0027] The engine dual-fuel controller has a fault diagnosis function, which monitors the working status of each sensor and actuator of the system in real time and diagnoses the function. If the methanol level is too low or methanol leaks, the engine dual-fuel controller automatically switches to pure diesel working mode. At this time, the methanol pump no longer works, and the fault location is displayed on the display module. At the same time, the built-in buzzer of the display module starts to work, issuing a buzzer alarm and cooperating with the photoelectric alarm light to remind the driver to avoid serious consequences. The engine dual-fuel controller encodes and stores fault codes according to the fault type and fault coding principle.

[0028] The data monitoring and mode switching module is installed in the cab. The data monitoring module is used by the driver to monitor the system's water temperature, engine speed, methanol tank level, methanol injection pressure, methanol injection pulse width and fault codes. The mode switching module is integrated into the data monitoring module and manually switches between pure diesel and methanol / diesel dual-fuel operating modes by touching the buttons.

[0029] When the engine is in methanol / diesel dual-fuel working mode, the parameter calibration module calibrates the diesel injection amount, diesel injection timing, methanol injection amount, and methanol injection timing under all working conditions, taking the knock sensor signal, oxygen concentration signal, engine power, and substitution rate as constraints.

[0030] When the engine is in methanol / diesel dual-fuel working mode, the engine's injector is driven by the methanol / diesel dual-fuel controller. In order to allow the engine ECU to form a closed-loop drive circuit, a simulated load is used instead of the engine injector. In order to avoid ECU fault reporting, an injector of the same model as the engine injector is used as a simulated load, so that the current in the circuit is exactly the same as that in pure diesel single fuel.

[0031] At the same time, isolation technology is used between each drive circuit. In order to reduce the number of simulated loads and reduce costs, as long as the injection phases do not overlap, one simulated load can be shared. For example, for a six-cylinder engine, the ignition sequence is 1-5-3-6-2-4, and cylinders 1, 2, and 3 are 240°CA apart, respectively, and can share one simulated load. Cylinders 4, 5, and 6 can share one simulated load.

[0032] In order to avoid heat generation during operation and reduce the working life of the simulated load, a cooling device is installed at the simulated load. The cooling device adopts oil cooling, in which methanol is used as the cooling medium and is connected in series in the methanol supply system. On the one hand, it cools the simulated load and takes away the heat generated by the simulated load; on the other hand, it heats the methanol, which helps to quickly vaporize the injected methanol.

[0033] The working principle diagram of the system is as follows Figure 1 As shown, the specific working principle is as follows: The T15 signal of the engine ECU, the common rail pressure sensor signal, the engine intake temperature / pressure sensor signal, the engine coolant temperature sensor signal, and the high, low and side drive signals of the 1-6 cylinder injectors are introduced into the methanol / diesel dual-fuel controller, and the methanol / diesel dual-fuel controller outputs the engine's 6 injectors and 2 simulated load drive signals.

[0034] After T15 is powered on, the system determines the working mode. If it is pure oil mode, the mode switching relay does not work, and this controller plays a role of wire connection. The injector is controlled by the engine ECU. If it is methanol / diesel dual fuel mode, each sensor is sampled, A / D converted, and converted into corresponding physical values.

[0035] If the methanol tank level is too low, it is impossible to switch to the methanol / diesel dual fuel mode, and the monitoring display screen prompts that the methanol level is too low. If the methanol level meets the switching conditions, it is determined whether the coolant temperature meets the switching conditions. When the temperature is too low, due to the poor methanol atomization effect, it is easy to cause the lubricating oil to emulsify and fail to switch.

[0036] The system keeps detecting the coolant temperature. When the temperature reaches the switching condition, the system calculates the engine speed based on the crankshaft position signal and captures the missing teeth of the crankshaft. After the missing teeth are determined, each tooth is numbered. The first tooth after the missing teeth is tooth 0, and at tooth 0, the crankshaft analog signal with an accuracy of 0.1°CA is synchronously output, and the teeth of the analog signal are numbered. At the same time, the phase of the first injection signal of the first cylinder is captured. If the missing tooth phase is greater than 90°CA, the current tooth number is reduced by 58, and the tooth number of the analog signal is also adjusted.

[0037] The phase and pulse width of the injection signal captured by each cylinder are calculated and stored, and the main injection is determined according to the pulse width of each injection. The injection phase and pulse width of the main injection are used as the basic parameters for the next cycle injection. After the calibration parameters are corrected, the drive signal is output as the final control parameter. When the injection parameters of each cylinder in a cycle are determined, the relay is turned on and switched to the dual-fuel working mode.

[0038] The parameter calibration module uses performance characterization parameters such as engine power and emissions as constraints, and uses engine intake pressure and total injection pulse width as load characterization parameters, and engine speed to construct an injection pulse width and speed MAP table, calibrates correction parameters such as diesel substitution rate and injection timing, constructs an intake pressure and speed, and injection pulse width and speed MAP table, and calibrates the methanol injection amount correction parameters.

[0039] The parameter calibration module uses the XCP protocol to communicate with the controller, has the function of storing and replaying calibration parameters, and has the function of downloading the control program through the calibration software.

[0040] Therefore, the present invention adopts the above-mentioned methanol-diesel dual-fuel control system for diesel vehicles in use, which can accurately control the ignition diesel injection phase and ignition fuel injection amount according to needs, thereby achieving better power and economy.

[0041] It is worth noting that the contents not elaborated in detail in the present invention are all prior art and are well known to those skilled in the art.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A methanol-diesel dual-fuel control system for an in-use diesel vehicle, characterized in that: It includes an engine controller, a methanol / diesel dual-fuel controller, a data monitoring and mode switching module, a parameter calibration module, a simulated load and cooling device, a knock detection module, an oxygen concentration detection module, a methanol pump and injection module, and a remote liquid level intelligent monitoring module. The methanol / diesel dual-fuel controller receives a mode switching signal, an engine crankshaft position sensor signal, an engine intake pressure / temperature sensor signal, an engine coolant temperature sensor signal, an engine common rail pressure sensor signal, a knock sensor signal, and an oxygen sensor signal through a T15 signal line; When the engine is in the diesel / methanol dual-fuel working mode, the methanol / diesel dual-fuel controller starts the methanol pump and drives the methanol nozzle to spray methanol in the Peak & Hold mode. The methanol nozzle is located at the connection between the engine intake pipe and the engine body. When the number of cycles reaches the calibration value, the mode switching relay is turned on to drive the injectors of each cylinder in the Peak & Hold mode. The methanol / diesel dual-fuel controller communicates with the data monitoring and mode switching module and the parameter calibration module through CAN. The system has a built-in analog crankshaft signal that is synchronized with the engine crankshaft position sensor signal and has an accuracy of 0.1 degree crankshaft angle.

2. A methanol-diesel dual-fuel control system for an in-use diesel vehicle according to claim 1, characterized in that: The methanol / diesel dual-fuel controller calculates the engine speed, the missing teeth of the crankshaft position signal, the tooth number of each tooth in an engine working cycle, the phase of each injection pulse signal of each cylinder and the total injection pulse width of each cylinder through the engine crankshaft position sensor signal and the first cylinder injection signal; and calculates the total injection amount of each cylinder according to the engine common rail pressure sensor signal, the injector characteristics and the total injection pulse width of each cylinder in each cycle, and corrects the injection amount according to the oxygen sensor signal.

3. A methanol-diesel dual-fuel control system for an in-use diesel vehicle according to claim 2, characterized in that: The methanol / diesel dual-fuel controller determines whether the engine is in a pure diesel working mode or a diesel / methanol dual-fuel working mode according to a mode switching signal.

4. A methanol-diesel dual-fuel control system for an in-use diesel vehicle according to claim 3, characterized in that: When the engine is in pure diesel working mode, the mode switching relay is not turned on and the engine ECU directly drives the injector.

5. The methanol-diesel dual-fuel control system for an in-use diesel vehicle according to claim 3, characterized in that: When the engine is in diesel / methanol dual-fuel operation mode, the engine dual-fuel controller drives the injector to inject diesel, determines the injection amount of each cylinder in each cycle according to the oxygen sensor signal and the calibrated control parameters, injects at the main injection phase of the previous cycle, and adjusts the injection phase according to the knock sensor signal and the calibration parameters; The engine dual-fuel controller communicates with the parameter calibration module and the data monitoring module in real time; when the engine is in diesel / methanol dual-fuel working mode, the engine injector is driven by the same Peak&Hold driving method and the same driving voltage and current parameters as the original engine ECU.

6. A methanol-diesel dual-fuel control system for an in-use diesel vehicle according to claim 5, characterized in that: The data monitoring module is installed in the cab and is used by the driver to monitor the water temperature, engine speed, methanol tank liquid level, methanol injection pressure, methanol injection pulse width and fault codes of the system; the mode switching module is integrated in the data monitoring module and is manually switched between pure diesel and diesel / methanol dual-fuel operating modes by touching the buttons.

7. A methanol-diesel dual-fuel control system for an in-use diesel vehicle according to claim 6, characterized in that: When the engine is in diesel / methanol dual-fuel working mode, the parameter calibration module calibrates the diesel injection amount, diesel injection timing, methanol injection amount and methanol injection timing under all working conditions, taking the knock sensor signal, oxygen concentration signal, engine power and substitution rate parameters as constraints.

8. A methanol-diesel dual-fuel control system for an in-use diesel vehicle according to claim 7, characterized in that: When the engine operating mode is the diesel / methanol dual-fuel operating mode, the same type of injector as the engine is used as the simulated load, the engine ECU drives the simulated load, isolation technology is used between the drive circuits, and the injector drive circuit forms a closed loop.

9. A methanol-diesel dual-fuel control system for an in-use diesel vehicle according to claim 8, characterized in that: A cooling device is provided at the simulated load, and the cooling device is connected in series to the methanol supply system. The cooling method thereof adopts oil cooling, wherein methanol is used as the cooling medium.

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