CN108278162B - Diesel and natural gas dual-fuel engine electronic control unit supporting multi-point injection of natural gas - Google Patents

Abstract

The invention relates to an electronic control unit of a diesel and natural gas dual-fuel engine supporting multi-point injection of natural gas. Including the microprocessor and peripheral circuits, as well as the power management module connected to the electronic control unit, the crankshaft and camshaft position signal acquisition module, the exhaust temperature signal acquisition module, the analog signal acquisition module, the solenoid valve drive module, the low-side drive module, Current detection module, communication module. Compared with the prior art, the present invention can independently control the diesel injection solenoid valve and the natural gas injection solenoid valve at the same time without installing other equipment such as signal transponders, and at the same time improves the traditional solenoid valve drive circuit and increases the high-voltage drive power supply, The opening time and power consumption of the solenoid valve are reduced, and the injection is more accurate; the invention can adopt the method of multi-point sequential injection to realize the timing supply of pilot fuel and natural gas to each cylinder, and effectively improve the working performance of the natural gas/diesel dual fuel engine .

Description

Diesel and natural gas dual-fuel engine electronic control unit supporting multi-point injection of natural gas

technical field

The invention relates to an electronic control unit of a diesel and natural gas dual-fuel engine supporting multi-point injection of natural gas.

Background technique

Natural gas/diesel dual-fuel engines are currently mostly modified from original diesel engines. On the basis of retaining the original vehicle electronic control unit, a set of natural gas injection control unit is added, including adding an electronic control unit and sensor signal transponder. On the one hand, most of the modification schemes currently in use use the single-point injection method of natural gas in the engine intake manifold, which cannot accurately control the injection time, and the combustion control is not good; on the other hand, the natural gas electronic control unit used for modification has problems that cannot directly collect Vehicle signal, using the traditional solenoid valve drive method and poor control accuracy, etc., resulting in the modification effect often not meeting expectations, and the addition of an electronic control unit also increases the overall complexity of the electronic control unit, which is not conducive to the development of diesel engine oil to gas technology Therefore, it is imperative to improve and innovate the electronic control unit for diesel-natural gas dual-fuel engines that support natural gas multi-point injection.

Contents of the invention

The purpose of the present invention is to overcome the disadvantages of the prior art and provide an electronic control unit for a diesel and natural gas dual fuel engine that supports multi-point injection of natural gas, which can effectively improve the working performance of the natural gas/diesel dual fuel engine and reduce the complexity of the installation of the electronic control unit Spend.

In order to achieve the above object, the technical solution of the present invention is: an electronic control unit for a diesel and natural gas dual-fuel engine that supports multi-point injection of natural gas, including a microprocessor and a memory module connected thereto, a power management module, a solenoid valve drive module, a low Side drive module, current detection module, crankshaft and camshaft position signal acquisition module, throttle position signal acquisition module, pressure signal acquisition module, cooling water temperature signal acquisition module, exhaust temperature signal acquisition module, communication module;

The microprocessor includes a main central processing unit and a co-processor; the main central processing unit is used for responding to task interruption, executing control strategies and communication tasks when the electronic control unit is in the single-fuel working mode; the co-processor Processor, used for interrupt response of diesel and natural gas injection tasks when the electronic control unit is in dual-fuel working mode;

The memory module includes a Flash memory, which is used to store all the MAP data required by the engine in the single-fuel/dual-fuel working mode, so that the electronic control unit can load the preset configuration information and perform system initialization when the electric control unit is powered on again;

The power management module converts the voltage of the automobile battery into the voltage required for the work of each sensor, actuator, and control chip; includes a Boost boost circuit, a Buck voltage drop circuit, and a linear stabilization circuit; wherein, the peripheral power devices of the Boost boost circuit The input terminal is connected to the car battery, and the car battery power is converted into a +60V high-voltage driving power supply, and the output terminal is connected to the solenoid valve drive module; the Buck step-down circuit converts the car battery power supply into a 5V power supply, which is used for active sensors and microprocessors and The peripheral circuit supplies power; the linear voltage regulator circuit converts the power supply of the car battery into a 15V power supply, which supplies power for the high and low side drivers of the solenoid valve drive module;

The solenoid valve driving module includes: a high-low side driver, a first peripheral circuit, a high-side NMOS tube Q400, a high-side NMOS tube Q402, a low-side cylinder selection NMOS tube Q401, a low-side cylinder selection NMOS tube Q403, an isolation diode D404, and an isolation diode D404. Diode D405, two load solenoid valves L400 and L401; the source of the high-side NMOS tube Q400, the isolation diode D404, the sampling resistor R404 of the current detection module, the solenoid valve L400, and the low-side cylinder selection NMOS tube Q401 are connected in series in sequence , forming the first circuit of the load; the source of the high-side NMOS tube Q402, the isolation diode D405, the sampling resistor R404 of the current detection module, the solenoid valve L401, and the low-side cylinder selection NMOS tube Q403 are connected in series in sequence to form the second load circuit Loop: the high-side driver receives the high-side control pulse A _h , the high-side control pulse B _h and the low-side control pulse C _l sent by the microprocessor, and outputs the high-side drive for connecting the high-voltage source through the high-low side driver The pulse A _H , the high-side drive pulse B _H for connecting the low-voltage source and the low-side drive pulse _CL for cylinder selection are respectively sent to the gates of the high-order NMOS transistor Q400 and the high-order NMOS transistor Q405 and the low-order NMOS transistor Q401 or Q403 The grid of the high-order NMOS transistor Q400 is connected to the output terminal of the Boost power supply module, and the drain electrode of the high-order NMOS transistor Q402 is connected to the output terminal of the car battery;

The low-side driver module includes a low-side driver, a second peripheral circuit, a power NMOS transistor, and a freewheeling diode;

The current detection module includes a sampling resistor R404, a current detection amplifier, and a third peripheral circuit; the sampling resistor R404 is on the high side of the solenoid valve, and is used to detect the working current of the solenoid valve; the current detection amplifier divides the sampling resistor R404 The differential voltage on the side is amplified and then passed to the microprocessor;

The crankshaft and camshaft position signal acquisition module is used to adjust the gear position signals on the crankshaft and camshaft of the engine;

The throttle position signal acquisition module, the pressure signal acquisition module, the cooling water temperature signal acquisition module, and the exhaust temperature signal acquisition module are respectively used to adjust the throttle position signal, pressure signal, cooling water temperature signal, and exhaust temperature signal of the engine;

The communication module includes a CAN bus communication module, which is used for two-way communication with the calibration software of the engine, so as to facilitate monitoring and calibration of control parameters of the engine.

In an embodiment of the present invention, when the electronic control unit is in the diesel single-fuel working mode, the main central processing unit receives the signals of each acquisition module, calculates the control parameters according to the control strategy, controls the fuel injection solenoid valve, and realizes the corresponding fuel injection Quantity supply; the electronic control unit is in the natural gas/diesel dual fuel working mode, the main central processing unit collects sensor signals, and according to the control strategy, the main central processing unit controls the operation of the diesel injection solenoid valve, and the coprocessor controls the natural gas injection The work of the solenoid valve realizes the supply of pilot fuel and natural gas.

In one embodiment of the present invention, the microprocessor determines the working timing and timing of the two high-level control pulse signals and one low-level control pulse signal in the solenoid valve drive module by collecting the position signals of the crankshaft and the camshaft. duration.

In an embodiment of the present invention, when the solenoid valve drive module drives the solenoid valve, the microprocessor collects the solenoid valve operating current signal of the current detection module, and configures the solenoid valve with different The driving voltage controls the opening time and opening duration of the solenoid valve.

In an embodiment of the present invention, the electronic control unit has 6 solenoid valve drive modules, wherein every 2 solenoid valve drive modules form a group, and a group of solenoid valve drive modules can drive the diesel injection solenoid valve corresponding to one cylinder of the engine. and natural gas injection solenoid valve; the microprocessor first calculates the injection start time and the injection quantity of diesel and natural gas for the X cylinder of the engine, and then controls the diesel injection solenoid valve and the natural gas injection solenoid valve through the solenoid valve drive module corresponding to the cylinder In one working cycle of the engine, the diesel injection solenoid valve and the natural gas injection solenoid valve of each cylinder perform sequential multi-point injection.

Compared with the prior art, the present invention has the following beneficial effects: Compared with the prior art, the present invention can simultaneously independently control the diesel injection solenoid valve and the natural gas injection solenoid valve without installing other equipment such as signal transponders, At the same time, the traditional solenoid valve drive circuit is improved, the high-voltage drive power is increased, the solenoid valve opening time and power consumption are reduced, and the injection is more accurate; the invention can adopt the method of multi-point sequential injection to realize the timing supply of pilot fuel to each cylinder With natural gas, it can effectively improve the working performance of natural gas/diesel dual fuel engine.

Description of drawings

Fig. 1 is a structural schematic diagram of the connection between the present invention and other parts of the electronic control unit.

Fig. 2 is a schematic diagram of the internal structure of the present invention.

FIG. 3 is a schematic diagram of a Buck voltage reducing circuit and a linear voltage stabilizing circuit in the power management module of the present invention.

FIG. 4 is a schematic diagram of the Boost voltage boosting circuit in the power management module of the present invention.

Fig. 5 is a circuit schematic diagram of the solenoid valve drive module and the current detection module of the present invention.

Fig. 6 is a timing diagram of the operation of the solenoid valve driving module of the present invention.

FIG. 7 is a circuit schematic diagram of the low-side driving module of the present invention.

Fig. 8 is a schematic circuit diagram of the crankshaft and camshaft signal acquisition module of the present invention.

Fig. 9 is a schematic diagram of the analog signal input circuit of the present invention.

Fig. 10 is a schematic circuit diagram of the exhaust gas temperature signal acquisition module of the present invention.

Fig. 11 is a schematic diagram of the switch signal input circuit of the present invention.

Fig. 12 is a circuit schematic diagram of the CAN bus module of the present invention.

detailed description

The technical solution of the present invention will be specifically described below in conjunction with the accompanying drawings.

An electronic control unit of a diesel and natural gas dual-fuel engine supporting multi-point injection of natural gas of the present invention includes a microprocessor and a memory module connected thereto, a power management module, a solenoid valve drive module, a low-side drive module, a current detection module, and a crankshaft With camshaft position signal acquisition module, accelerator position signal acquisition module, pressure signal acquisition module, cooling water temperature signal acquisition module, exhaust temperature signal acquisition module, communication module;

The microprocessor includes a main central processing unit and a co-processor; the main central processing unit is used for responding to task interruption, executing control strategies and communication tasks when the electronic control unit is in the single-fuel working mode; the co-processor Processor, used for interrupt response of diesel and natural gas injection tasks when the electronic control unit is in dual-fuel working mode;

The memory module includes a Flash memory, which is used to store all the MAP data required by the engine in the single-fuel/dual-fuel working mode, so that the electronic control unit can load the preset configuration information and perform system initialization when the electric control unit is powered on again;

The power management module converts the voltage of the automobile battery into the voltage required for the work of each sensor, actuator, and control chip; includes a Boost boost circuit, a Buck voltage drop circuit, and a linear stabilization circuit; wherein, the peripheral power devices of the Boost boost circuit The input terminal is connected to the car battery, and the car battery power is converted into a +60V high-voltage driving power supply, and the output terminal is connected to the solenoid valve drive module; the Buck step-down circuit converts the car battery power supply into a 5V power supply, which is used for active sensors and microprocessors and The peripheral circuit supplies power; the linear voltage regulator circuit converts the power supply of the car battery into a 15V power supply, which supplies power for the high and low side drivers of the solenoid valve drive module;

The solenoid valve driving module includes: a high-low side driver, a first peripheral circuit, a high-side NMOS tube Q400, a high-side NMOS tube Q402, a low-side cylinder selection NMOS tube Q401, a low-side cylinder selection NMOS tube Q403, an isolation diode D404, and an isolation diode D404. Diode D405, two load solenoid valves L400 and L401; the source of the high-side NMOS tube Q400, the isolation diode D404, the sampling resistor R404 of the current detection module, the solenoid valve L400, and the low-side cylinder selection NMOS tube Q401 are connected in series in sequence , forming the first circuit of the load; the source of the high-side NMOS tube Q402, the isolation diode D405, the sampling resistor R404 of the current detection module, the solenoid valve L401, and the low-side cylinder selection NMOS tube Q403 are connected in series in sequence to form the second load circuit Loop: the high-side driver receives the high-side control pulse A _h , the high-side control pulse B _h and the low-side control pulse C _l sent by the microprocessor, and outputs the high-side drive for connecting the high-voltage source through the high-low side driver The pulse A _H , the high-side drive pulse B _H for connecting the low-voltage source and the low-side drive pulse _CL for cylinder selection are respectively sent to the gates of the high-order NMOS transistor Q400 and the high-order NMOS transistor Q405 and the low-order NMOS transistor Q401 or Q403 The grid of the high-order NMOS transistor Q400 is connected to the output terminal of the Boost power supply module, and the drain electrode of the high-order NMOS transistor Q402 is connected to the output terminal of the car battery;

The low-side driver module includes a low-side driver, a second peripheral circuit, a power NMOS transistor, and a freewheeling diode;

The current detection module includes a sampling resistor R404, a current detection amplifier, and a third peripheral circuit; the sampling resistor R404 is on the high side of the solenoid valve, and is used to detect the working current of the solenoid valve; the current detection amplifier divides the sampling resistor R404 The differential voltage on the side is amplified and then passed to the microprocessor;

The crankshaft and camshaft position signal acquisition module is used to adjust the gear position signals on the crankshaft and camshaft of the engine;

The throttle position signal acquisition module, the pressure signal acquisition module, the cooling water temperature signal acquisition module, and the exhaust temperature signal acquisition module are respectively used to adjust the throttle position signal, pressure signal, cooling water temperature signal, and exhaust temperature signal of the engine;

The communication module includes a CAN bus communication module, which is used for two-way communication with the calibration software of the engine, so as to facilitate monitoring and calibration of control parameters of the engine.

The following are specific implementation examples of the present invention.

As shown in FIG. 1 , the present invention provides an electronic control unit for a diesel-natural gas dual-fuel engine that supports multi-point injection of natural gas. When the vehicle is powered on, the electric control unit 8 is powered by the vehicle battery 7 . The electronic control unit 8 collects signals from various sensors, including camshaft position signal sensor 1, throttle position signal sensor 2, pressure signal sensor 3, temperature signal sensor 4, and crankshaft position signal sensor 6. These signals are conditioned by different signal processing circuits , and finally received by the microprocessor, and then according to the corresponding control strategy, control signals are sent to the diesel injection solenoid valve 10 and the natural gas injection solenoid valve 11, and the solenoid valves work according to the signals. The diesel-natural gas dual-fuel engine electronic control unit 8 that supports multi-point injection of natural gas performs two-way communication through the CAN bus module and the PC-side calibration software 9, which is convenient for online calibration.

As shown in Figure 2, the diesel-natural gas dual-fuel engine electronic control unit supporting multi-point injection of natural gas is an integrated circuit board, which includes a microprocessor chip 7 and an external memory module 10, connected to the microprocessor Crankshaft and camshaft position signal acquisition module 1, accelerator position signal acquisition module 2, pressure signal acquisition module 3, temperature signal acquisition module 4, exhaust temperature signal acquisition module 5, CAN bus module 6, solenoid valve drive module 8, current Detection module 9, low-side drive module 11; microprocessor chip 7 receives crankshaft and camshaft position signal acquisition module 1, throttle position signal acquisition module 2, pressure signal acquisition module 3, temperature signal acquisition module 4 and exhaust temperature signal acquisition The signal conditioned by the module 5 also collects the current signal fed back by the current detection module 9 when the solenoid valve is working; the output signal of the microprocessor chip 7 controls the solenoid valve drive module 8 and the low-side drive module 11; the microprocessor chip 7 passes the SPI The communication protocol reads and stores information on the peripheral memory module 10; the microprocessor chip 7 selects the MC9S12XET256 single-chip microcomputer of the S12 series of Freescale Corporation, the memory chip 10 selects W25Q40228, and the message transceiver of the CAN bus module selects TJA1050.

Figure 3 shows the schematic diagram of Buck step-down circuit and linear voltage regulator circuit, and Figure 4 shows the schematic diagram of Boost boost circuit. The power management module of the present invention mainly includes a Buck step-down circuit, a linear voltage regulator circuit, and a Boost boost circuit, and the power management module is used to provide power for a microprocessor and peripheral circuits, sensors and actuators. The positive and negative poles of the car battery power supply are respectively connected to the power management module of the electronic control unit through BATTERY+ and BATTERY-, and are divided into two circuits here. voltage circuit and linear voltage regulator circuit.

As shown in Figure 3, the positive pole of the battery power supply is first connected to the cathode end of the TVS diode D103 to protect the back-end components, and then connected to the large electrolytic capacitor C108 to absorb the peak pulse of the car battery, and then connected to the common mode filter L101 to get 24V power supply with less ripple. The 24V power supply is divided into three circuits. The circuit leads to the solenoid valve drive module as a low-voltage drive power supply. In the 24V to 5V Buck step-down circuit, U101 (model LM2596) is selected as the control chip of the circuit, and the output 5V voltage is mainly used to supply power to the microprocessor, peripheral circuits and sensors connected to the electronic control unit. The 24V to 15V linear voltage regulator circuit uses U101 (model LM317) as the control chip of the circuit, and the output 15V voltage supplies power to the high and low side drivers in the solenoid valve drive module.

As shown in Figure 4, the Boost boost circuit uses U103 (model LM3488) as the boost circuit control chip. The peripheral power devices of the boost circuit include: input capacitors C104 and C106, inductor L101, diode D107, NMOS transistor Q402, output capacitors C113, C115 and C117, and resistor R117. One end of the inductor L101 is connected to the positive electrode of the battery voltage, and the other end is connected to the 3-pin (drain) of the NMOS transistor Q402. The anode of the diode D107 is connected to the output terminal of the high-voltage power supply of the solenoid valve drive module, and the cathode is grounded through the output capacitors C113, C115 and C117. The gate of the NMOS transistor Q402 is connected to the 6-pin (DR) of the control chip U103 (LM3488), the source is connected to the 1-pin (ISEN) of the control chip U103 through the RC filter circuit, and the source is grounded through the resistor R117. The car battery input voltage is grounded through capacitors C104 and C106.

As shown in FIG. 5 , the circuit schematic diagram of the solenoid valve drive module and the current detection module of the present invention, the solenoid valve drive module of the present invention mainly includes two high-side and low-side drive circuits and a load circuit. The present invention has 2 diesel injection solenoid valve drive modules and 2 natural gas injection solenoid valve drive modules, wherein each solenoid valve module can drive 2 solenoid valves. Because the principles are the same, only one solenoid valve module description is listed in the figure. As shown in Figure 5, it includes two high and low side drive circuits, a load circuit and a current sampling circuit, which can drive two solenoid valves L400 and L401; among them: pin 1 (VCC) of the high and low side driver U400 (the model is IR2101S) Connect to external power supply +15V, 2 pins (HIN) to control pulse signal source output pin PA1_, 3 pins (LIN) to control pulse signal source output pin PA0_, 4 pins (COM) to circuit board ground ( GND), pin 5 (LO) is connected to resistor R100, pin 6 (VS) is connected to capacitor C401, pin 7 (HO) is connected to resistor R401, pin 8 (VB) is connected to the cathode of diode D400; one end of capacitor C400 is connected to External power supply +15V, the other end is grounded; the anode of diode D400 is connected to external power supply +15V, the cathode is connected to port 8 of high and low side driver U400; the positive pole of capacitor C401 is connected to pin 8 (VB) of high and low side driver U400, and the negative pole is connected to U400’s 6-pin (VS); the anode of diode D402 is connected to pin 1 (gate) of NMOS transistor Q400, and the cathode is connected to pin 7 (HO) of U400; the anode of diode D401 is connected to pin 1 (gate) of NMOS transistor Q4001 ), the cathode is connected to pin 5 (LO) of U400; one end of resistor R401 is connected to pin 7 (HO) of U400, and the other end is connected to pin 1 (gate) of NMOS transistor Q400; one end of resistor R400 is connected to pin 5 of U400 Pin (LO), the other end is connected to pin 1 (gate) of NMOS transistor Q401; the cathode of common anode diode D404 is connected to one end of sampling resistor R404; pin 2 (drain) of NMOS transistor Q400 is connected to high-voltage drive power +60V, pin 3 (source) is connected to the anode of common anode diode D104; pin 2 (drain) of NMOS tube Q401 is connected to pin 1 of solenoid valve L400, pin 3 (source) is connected to GND of the circuit board (the negative pole of the power supply); one end of the capacitor C406 is connected to the external power supply +15V, and the other end is grounded. Pin 1 (VCC) of the high and low side driver U402 is connected to the external power supply +15V, pin 2 (HIN) is connected to the PWM signal source output pin PWM0_, pin 3 (LIN) is connected to the control pulse signal source output pin PA2_, pin 4 Pin (COM) is connected to the ground (GND) of the circuit board, pin 5 (LO) is connected to the resistor R405, pin 6 (VS) is connected to the negative pole of the capacitor C405, pin 7 (HO) is connected to the resistor R405, pin 8 (VB ) is connected to the cathode of diode D409; the anode of diode D409 is connected to external power supply +15V, the cathode is connected to port 8 of high and low side driver U402; the positive pole of capacitor C405 is connected to pin 8 (VB) of high and low side driver U402, and the negative pole is connected to pin 6 of U402 pin (VS); the anode of diode D407 is connected to pin 1 (gate) of NMOS transistor Q402, and the cathode is connected to pin 7 (HO) of U402; the anode of diode D408 is connected to pin 1 (gate) of NMOS transistor Q403, The cathode is connected to pin 5 (LO) of U402; one end of resistor R405 is connected to pin 7 (HO) of U402, and the other end is connected to pin 1 (gate) of NMOS tube Q402; one end of resistor R406 is connected to pin 5 of U402 (LO), the other end is connected to pin 1 (gate) of NMOS transistor Q403; the cathode of common anode diode D405 is connected to one end of sampling resistor R404; pin 2 (drain) of NMOS transistor Q402 is connected to low-voltage driving power supply +24V , the 3-pin (source) is connected to the anode of the common anode diode D405; the 2-pin (drain) of the NMOS tube Q403 is connected to the 1-pin of the solenoid valve L400, and the 3-pin (source) is connected to the GND (power supply) of the circuit board negative electrode).

In the current detection module shown in Figure 5, the resistor R404 is a sampling resistor, and one end is connected to the 6-pin (VS) of the high-low side driver (U400 and U402) and the 1-pin (cathode) of the common anode diode (D404 and D405); One end of resistor R403 is connected to pin 8 (+IN) of U401, and the other end is connected to sampling resistor R404; one end of resistor R402 is connected to pin 1 (-IN) of U401, and the other end is connected to sampling resistor R404; one end of capacitor C404 is connected to U401 The other end of the capacitor C402 is connected to the 6-pin (+VS) of U401, and the other end of the capacitor C402 is connected to the GND (negative pole of the power supply) of the circuit board; U401 The 1-pin (-IN) is connected to one end of the resistor R402, the 2-pin (GND) is connected to the GND (negative pole of the power supply) of the circuit board; the 3-pin (VREF2) is connected to the 2-pin (GND); the 4-pin (NC ) is not connected to other devices; 5-pin (OUT) is connected to the analog-to-digital conversion channel AD00_ of the computing unit; 6-pin (+VS) is connected to an external +5V power supply; 7-pin (VREF1) is connected to 6-pin (+VS ) connection; 8 pins (+IN) connected to one end of resistor R103;

Take the operation of the solenoid valve L400 as an example to illustrate the working process of the solenoid valve drive module:

First of all, in the internal program setting of the microprocessor, different control parameters will be set for the diesel injection solenoid valve and the natural gas injection solenoid valve, and these control parameters will be adjusted in real time according to the working conditions of the engine.

The sequence of the working process is shown in Figure 6. At time T1, the _{PA0_} pin of the microprocessor sends a C _L pulse signal, which is converted into a C _L pulse signal by the high and low side driver U400 and transmitted to the 1 pin (gate) of Q400 , at this time the field effect transistor Q401 is turned on. At T2 time, the _{PA1_} pin of the microprocessor sends out the A _h pulse signal, which is converted into A _H pulse signal by U400 and transmitted to the 1 pin (gate) of Q400, and Q400 is turned on at this time. The conduction of Q400 and Q400 connects the solenoid valve L400 to the +60V high-voltage driving power supply, and the +60V high-voltage driving power quickly increases the operating current of the solenoid valve to open the solenoid valve in a short time. From time T1, the microprocessor starts to continuously collect the operating current _of the solenoid valve through the current detection module. _At time T3, when the current value reaches a certain threshold, the microprocessor stops sending the _Ah control signal, and the field effect transistor Q400 is turned off at this time , the +60V high-voltage drive power supply is disconnected from the solenoid valve, and the operating current of the solenoid valve drops rapidly. At T4, the current value drops to a certain threshold. _At T5, the _{PWM0_} pin of the microprocessor sends out a B _h pulse signal , which is converted into B _H pulse signal by U402 and transmitted to pin 1 (gate) of Q402. At this time, the field effect transistor Q402 is turned on, and the +24V low-voltage driving power is applied to the solenoid valve L400. Since the solenoid valve has been in T ₂ - It is turned on during the period of T ₃ , so the +24V low-voltage drive power supply can keep the solenoid valve open at this time, and the working current of the solenoid valve is switched from a larger opening current to a smaller holding current, which reduces power consumption and prolongs the solenoid valve. service life of the valve. At T ₆ , the B _H pulse signal ends, and the +24V low-voltage driving power supply is disconnected from the solenoid valve. Then, at T ₇ , the microprocessor closes the PA0_ pin, and C _L also ends. At this time, the driving current passes through the freewheeling Diode D49, the current drops rapidly to zero, and the working process of a solenoid valve drive ends.

As shown in Figure 7, the circuit schematic diagram of the low-side driver module, the low-side driver module includes: a low-side driver chip, a power NMOS transistor and a freewheeling diode. The module uses U404 (model A3944) as the low-side driver chip, pin 23 (CSN), pin 24 (SI), pin 25 (SCK), pin 26 (SO) and the SPI module of the microprocessor Connection, pin 27 is connected to the ordinary IO port of the microprocessor, and pins 17 (IN0), 18 (IN1), 19 (IN2), 20 (IN3), 21 (IN4), and 22 (IN5) are respectively connected to the microprocessor The PB0, PB1, PB2, PB3, PB4, PB5 pins of the device are connected to receive the pulse control signal sent by the microprocessor. The pin GATx (x represents 0-5) of U404 is connected to the gate of the NMOS transistor Q40x (x represents 4-9, the model is Auirfr540z) through the spike suppression resistor, and GDRNx (x represents 0-5) are the faults corresponding to GATx The diagnostic signal feedback pin is connected to the low-side pin of the actuator through a current-limiting resistor. There are 6 low-side drivers in the present invention. Because the principle is the same, it is explained by driving the actuator CON400: when the microcontroller inputs a pulse control signal to the U404 input terminal INx (x represents 0-5), the pulse control signal is converted by U404, Through the output of the GATx (x represents 0-5) pins to the gate of the NMOS transistor Q402, the NMOS transistor Q404 is turned on, the actuator is connected to the +24V power supply, and the actuator starts to work. When the control signal of the microprocessor stops, The NMOS transistor Q404 is turned off immediately, the working current flows through the freewheeling diode D410 and drops to zero rapidly, and the working process ends. The microprocessor can inquire in real time through the SPI communication module whether the 6 low-side drive circuits controlled by U404 are in the normal, short circuit, open circuit or open circuit state.

As shown in Figure 8, the crankshaft and camshaft signal acquisition module circuit schematic diagram of the present invention, the signal output terminal CRANKSHIFT of the crankshaft position signal sensor is connected to the 2-pin (IN1) of U201 (the model is selected as NCV1124) through the resistor R203, and the camshaft The signal output terminal CAMSHIFT of the position signal sensor is connected to the 3-pin (IN2) of U201 through the resistor R204, and the capacitor C202 is a filter capacitor. Pin 6 (OUT1) of U201 is connected to IOC0_ of the microprocessor to transmit the conditioned crankshaft position signal to the microprocessor, and pin 7 (OUT1) of U201 is connected to IOC1_ of the microprocessor to transmit the conditioned crankshaft position signal to the microprocessor. The camshaft position signal is transmitted to the microprocessor.

As shown in the schematic diagram of the analog signal input circuit in Figure 9, since the characteristics of the cooling water temperature signal, the intake air temperature signal, and the throttle position signal are the same, the circuit is also consistent. Now take the input signal of the cooling water temperature sensor as an example to illustrate. The cooling water temperature signal is sent from the NTC (negative temperature coefficient) thermistor temperature sensor. The resistance value of the thermistor changes with temperature and is converted into a corresponding output voltage. The sensor signal passes through the filter circuit composed of resistor R213 and capacitor C207. , sent to the analog-to-digital conversion channel of the microprocessor.

As shown in the schematic diagram of the circuit diagram of the exhaust temperature signal acquisition module in Figure 10, the engine exhaust temperature signal is sent by a K-type thermocouple, so the exhaust temperature signal acquisition module uses U204 (the model is selected as MAX6675) to collect and process the signal, and the K-type thermocouple The even signal is transmitted to U204 from both ends of THECOU- and THECOU+, and then the signal is transmitted to the microprocessor through the SPI communication module.

As shown in Figure 11, the schematic diagram of the switch signal input circuit, the present invention supports five switch inputs, and since the circuit principle is the same, one of them is now described. The external signal 24IN_1 passes through the voltage divider circuit composed of the resistor R232 and the resistor R233, then passes through the filter circuit composed of the resistor R237 and the capacitor C220, and finally inputs the converted level signal to the IN_PB2 pin of the microprocessor.

As shown in Figure 12 CAN bus module circuit schematic diagram, U200 (model TJA1050) is selected as the transceiver of the CAN bus message. 4 (RXD) pins are connected, 7 pins (CANH) and 6 pins (CANL) of U3 are connected to the CAN bus outside the electronic control unit, and according to the CAN bus principle, there is a Resistor R207 with a resistance value of 120 ohms. After the microprocessor sends the CAN bus message, it is converted by U200 and finally sends the message to the bus network.

The above-listed preferred embodiments have further described the purpose, technical solutions and advantages of the present invention in detail. It should be understood that the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Within the spirit and principles of the present invention, any modifications, equivalent replacements, improvements, etc., shall be included within the protection scope of the present invention.

Claims (5)

1. A diesel and natural gas dual-fuel engine electronic control unit that supports multi-point injection of natural gas is characterized in that: it includes a microprocessor and a memory module connected thereto, a power management module, a solenoid valve drive module, a low-side drive module, and a current detection Module, crankshaft and camshaft position signal acquisition module, accelerator position signal acquisition module, pressure signal acquisition module, cooling water temperature signal acquisition module, exhaust temperature signal acquisition module, communication module; The microprocessor includes a main central processing unit and a co-processor; the main central processing unit is used for responding to task interruption, executing control strategies and communication tasks when the electronic control unit is in the single-fuel working mode; the co-processor Processor, used for interrupt response of diesel and natural gas injection tasks when the electronic control unit is in dual-fuel working mode; The memory module includes a Flash memory, which is used to store all the MAP data required by the engine in the single-fuel/dual-fuel working mode, so that the electronic control unit can load the preset configuration information and perform system initialization when the electric control unit is powered on again; The power management module converts the voltage of the automobile battery into the voltage required for the work of each sensor, actuator, and control chip; includes a Boost boost circuit, a Buck voltage drop circuit, and a linear stabilization circuit; wherein, the peripheral power devices of the Boost boost circuit The input terminal is connected to the car battery, and the car battery power is converted into a +60V high-voltage driving power supply, and the output terminal is connected to the solenoid valve drive module; the Buck step-down circuit converts the car battery power supply into a 5V power supply, which is used for active sensors and microprocessors and The peripheral circuit supplies power; the linear voltage regulator circuit converts the power supply of the car battery into a 15V power supply, which supplies power for the high and low side drivers of the solenoid valve drive module; The solenoid valve driving module includes: a high-low side driver, a first peripheral circuit, a high-side NMOS tube Q400, a high-side NMOS tube Q402, a low-side cylinder selection NMOS tube Q401, a low-side cylinder selection NMOS tube Q403, an isolation diode D404, and an isolation diode D404. Diode D405, two load solenoid valves L400 and L401; the source of the high-side NMOS tube Q400, the isolation diode D404, the sampling resistor R404 of the current detection module, the solenoid valve L400, and the low-side cylinder selection NMOS tube Q401 are connected in series in sequence , forming the first circuit of the load; the source of the high-side NMOS tube Q402, the isolation diode D405, the sampling resistor R404 of the current detection module, the solenoid valve L401, and the low-side cylinder selection NMOS tube Q403 are connected in series in sequence to form the second load circuit Loop: the high-side driver receives the high-side control pulse A _h , the high-side control pulse B _h and the low-side control pulse C _l sent by the microprocessor, and outputs the high-side drive for connecting the high-voltage source through the high-low side driver The pulse A _H , the high-side drive pulse B _H for connecting the low-voltage source and the low-side drive pulse _CL for cylinder selection are respectively sent to the gates of the high-order NMOS transistor Q400 and the high-order NMOS transistor Q405 and the low-order NMOS transistor Q401 or Q403 The grid of the high-order NMOS transistor Q400 is connected to the output terminal of the Boost power supply module, and the drain electrode of the high-order NMOS transistor Q402 is connected to the output terminal of the car battery; The low-side driver module includes a low-side driver, a second peripheral circuit, a power NMOS transistor, and a freewheeling diode; The current detection module includes a sampling resistor R404, a current detection amplifier, and a third peripheral circuit; the sampling resistor R404 is on the high side of the solenoid valve, and is used to detect the working current of the solenoid valve; the current detection amplifier divides the sampling resistor R404 The differential voltage on the side is amplified and then passed to the microprocessor; The crankshaft and camshaft position signal acquisition module is used to adjust the gear position signals on the crankshaft and camshaft of the engine; The throttle position signal acquisition module, the pressure signal acquisition module, the cooling water temperature signal acquisition module, and the exhaust temperature signal acquisition module are respectively used to adjust the throttle position signal, pressure signal, cooling water temperature signal, and exhaust temperature signal of the engine; The communication module includes a CAN bus communication module, which is used for two-way communication with the calibration software of the engine, so as to facilitate monitoring and calibration of control parameters of the engine. 2. The diesel and natural gas dual-fuel engine electronic control unit supporting multi-point injection of natural gas according to claim 1, characterized in that: the electronic control unit receives each acquisition module by the main central processing unit under the diesel single-fuel working mode According to the control strategy, calculate the control parameters, control the fuel injection solenoid valve, and realize the supply of the corresponding fuel injection quantity; when the electronic control unit is in the natural gas/diesel dual fuel working mode, the main central processing unit collects the sensor signal, and according to the control strategy , the diesel injection solenoid valve is controlled by the main central processing unit, and the natural gas injection solenoid valve is controlled by the co-processor to realize the supply of pilot fuel and natural gas. 3. The diesel and natural gas dual-fuel engine electronic control unit supporting multi-point injection of natural gas according to claim 1, characterized in that: the microprocessor determines the solenoid valve according to the corresponding algorithm by collecting crankshaft and camshaft position signals The working timing and duration of two high-level control pulse signals and one low-level control pulse signal in the drive module. 4. The diesel and natural gas dual-fuel engine electronic control unit supporting multi-point injection of natural gas according to claim 1, characterized in that: when the solenoid valve driving module drives the solenoid valve, the microprocessor collects the solenoid valve of the current detection module The working current signal, according to the corresponding control strategy, configures different driving voltages for the solenoid valve at different time intervals, and controls the opening time and opening duration of the solenoid valve. 5. The diesel and natural gas dual-fuel engine electronic control unit supporting multi-point injection of natural gas according to claim 1, characterized in that: the electronic control unit has 6 solenoid valve drive modules, wherein every 2 solenoid valve drive modules are one A group of solenoid valve drive modules can drive the diesel injection solenoid valve and natural gas injection solenoid valve corresponding to one cylinder of the engine; the microprocessor first calculates the injection start time of the X cylinder of the engine and the injection amount of diesel and natural gas, Then, the working time of the diesel injection solenoid valve and the natural gas injection solenoid valve is controlled by the solenoid valve drive module corresponding to the cylinder, and the diesel injection solenoid valve and the natural gas injection solenoid valve of each cylinder are sequentially multi-point injected in an engine working cycle.

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