阅读说明：本技术 一种非对称式涡轮增压器的平衡阀控制系统及控制方法 (Balance valve control system and control method of asymmetric turbocharger ) 是由 谢爱元 胡猛 吴月 陈掌 张聪 张武凯 杨海涛 于 2020-06-18 设计创作，主要内容包括：本发明涉及一种非对称式涡轮增压器的平衡阀控制系统及控制方法；控制系统包括平衡阀控制阀、发动机控制单元、增压器平衡阀控制膜片阀、平衡阀阀片、增压器涡轮机；控制方法：1、发动机控制单元采集实际增压压力和EGR率；2、与目标增压压力、EGR率比较,确定是否需要调整；3、确定平衡阀控制阀目标出口空气压力；4、确定占空比,进行出口空气压力调节；5、实际出口空气压力作用于增压平衡阀控制膜片阀；6、阀芯移动使平衡阀阀片开度变化,引起增压器涡轮机输出功、涡前压力变化；7、改变压气机对空气做功量、改变增压压力；8、改变发动机EGR率；本发明降低了中高转速下涡前压力及发动机排气损失,提升了发动机的经济性能与环保性能。(The invention relates to a balance valve control system and a control method of an asymmetric turbocharger; the control system comprises a balance valve control valve, an engine control unit, a supercharger balance valve control diaphragm valve, a balance valve plate and a supercharger turbine; the control method comprises the following steps: 1. an engine control unit acquires actual boost pressure and EGR rate; 2. comparing with the target supercharging pressure and the EGR rate, and determining whether adjustment is needed; 3. determining a target outlet air pressure of a balance valve control valve; 4. determining a duty ratio, and adjusting outlet air pressure; 5. the actual outlet air pressure acts on a pressurization balance valve to control a diaphragm valve; 6. the valve core moves to change the opening of a valve plate of the balance valve, so that the output work and the preswirl pressure of the supercharger turbine are changed; 7. the work amount of the air compressor on the air is changed, and the supercharging pressure is changed; 8. changing an engine EGR rate; the invention reduces the pre-vortex pressure and the exhaust loss of the engine at medium and high rotating speeds, and improves the economic performance and the environmental protection performance of the engine.)

1. A balanced valve control system for an asymmetric turbocharger, characterized by:

the system comprises a compressed air storage tank (1), a balance valve control valve (2), an engine control unit (3), a supercharging pressure sensor (4), a supercharger balance valve control diaphragm valve (5), a balance valve plate (6), a supercharger turbine (7) and a supercharger compressor (8);

the engine control unit (3) is connected with the boost pressure sensor (4) and the balance valve control valve (2);

the left channel of the balance valve control valve (2) is communicated with the atmosphere, the right channel is an air outlet and is connected with the booster balance valve control diaphragm valve (5), and the lower channel is an air inlet and is connected with the compressed air tank (1);

the supercharging pressure sensor (4) is arranged on an engine air inlet pipeline in front of a throttle valve; the booster balance valve control diaphragm valve (5) is connected with a booster balance valve plate (6), the opening degree of the booster balance valve plate (6) is controlled through the outlet air pressure of the balance valve control valve (2), and the pressure of asymmetrical large and small flow passages in front of the booster turbine (7) is controlled; the supercharger compressor (8) is connected with the supercharger turbine (7) through a rotating shaft.

2. The balanced valve control system of an asymmetric turbocharger according to claim 1, characterized in that:

the engine control unit (3) is connected with the boost pressure sensor (4) and the balance valve control valve (2) and is used for controlling the output pressure of the balance valve control valve (2) based on the pressure data collected by the boost pressure sensor (4) so as to realize the opening control of the booster balance valve sheet (6).

3. The balanced valve control system of an asymmetric turbocharger according to claim 2, characterized in that:

the turbocharger turbine (7) adopts an asymmetric double-flow-channel structure, is matched with the balance valve control valve (2) for use, and realizes the arbitrary adjustment of the opening degree of the balance valve plate (6).

4. A method of controlling a balanced valve control system for an asymmetric turbocharger, comprising the steps of:

step 1, in the running process of an engine, an engine control unit (3) collects actual boost pressure and EGR rate according to a preset sampling frequency;

step 2, the engine control unit (3) compares the actual supercharging pressure and the EGR rate with target supercharging pressure and EGR rate to determine whether to adjust or not based on the collected actual supercharging pressure and EGR rate;

step 3, if the adjustment is not needed, jumping to step 9; if the adjustment is needed, determining the target outlet air pressure of the balance valve control valve, transmitting the target outlet air pressure to the balance valve control valve (2), and executing the step 4;

step 4, determining a duty ratio by the balance valve control valve (2) according to the target outlet air pressure, adjusting the outlet air pressure, and feeding back the actual outlet air pressure to the engine electric control unit (3) after the adjustment is finished;

step 5, the actual outlet air pressure of the balanced valve control valve (2) after the adjustment is finished acts on the pressurization balanced valve control diaphragm valve (5), so that a valve core of the pressurization balanced valve control diaphragm valve (5) moves;

step 6, the valve core of the supercharging balance valve control diaphragm valve (5) moves to change the opening of a balance valve plate (6), so that the output work and the pre-vortex pressure of the supercharger turbine (7) are changed;

step 7, changing the output work of the supercharger turbine (7) changes the work amount of the air compressor on the air, and further changes the supercharging pressure;

step 8, changing boost pressure and the pre-turbine pressure of the turbocharger turbine (7) changes the engine EGR rate;

and 9, ending.

5. The control method of the balanced valve control system of the asymmetric turbocharger according to claim 4, characterized in that:

the step 4 specifically comprises the following steps:

1) comparing the target outlet air pressure with the actual outlet air pressure to obtain a deviation between a required outlet air pressure and an actual outlet air pressure;

2) determining a calculated value of a demand solenoid valve duty cycle 1 based on the demand outlet air pressure;

3) determining a calculated value 2 of the duty ratio of the demand solenoid valve based on a deviation between the demand outlet air pressure and the actual outlet air pressure;

4) and a sum obtained by adding the determined calculated value 1 and the calculated value 2 is used as the duty ratio of the demand solenoid valve.

6. The control method of the balanced valve control system of the asymmetric turbocharger according to claim 5, characterized in that:

the calculated value 1 is obtained by an open-loop control method, specifically by looking up a characteristic table of a control valve of the balance valve;

the balance valve control valve characteristic table is a final control characteristic table determined through calibration tests in the engine development process.

7. The control method of the balanced valve control system of the asymmetric turbocharger according to claim 6, characterized in that:

the open-loop control algorithm specifically comprises the following contents:

and under different inlet pressures of the balance valve control valve, obtaining different outlet air pressures through different three-way electromagnetic valve openness, thus obtaining a balance valve control valve characteristic table.

8. The control method of the balanced valve control system of the asymmetric turbocharger according to claim 7, characterized in that:

the calculated value 2 is calculated by a PID closed-loop feedback control algorithm according to the deviation between the required outlet air pressure and the actual outlet air pressure in a preset period, and the calculated value 2 calculated by the PID closed-loop feedback control algorithm is also called a feedback control value.

9. The control method of the balanced valve control system of the asymmetric turbocharger according to claim 8, characterized in that:

the preset period is 10 ms.

10. The control method of the balanced valve control system of the asymmetric turbocharger according to claim 9, characterized in that:

in the step 1, the preset sampling frequency is 50 Hz.

Technical Field

The invention belongs to the technical field of internal combustion engine exhaust systems, relates to an internal combustion engine exhaust control system, and relates to a balance valve control system and a control method of an asymmetric turbocharger.

Background

To meet the requirements of ever-increasing emission legislation, the NOx emissions of internal combustion engines need to be continuously reduced. To meet this requirement, exhaust gas is often introduced into the engine intake manifold before the turbine inlet, referred to as Exhaust Gas Recirculation (EGR) technology. This requires a higher gas pressure before the turbine inlet, especially at low engine speed conditions, to establish a sufficient pressure differential across the EGR loop to ensure adequate EGR flow. This requires the use of a smaller turbine, raising the turbine preswirl pressure, and introducing sufficient EGR flow at low rpm. However, the pressure before the vortex is overlarge at medium and high rotating speeds, and the exhaust loss of the engine is increased and the fuel economy is deteriorated if the pressure is light; and the heavy condition causes the insufficient sealing condition of the exhaust end of the engine, the exhaust leakage or the overspeed damage of the turbocharger, and the engine can not work normally.

In order to weaken the adverse effect caused by excessive pressure before vortex at high rotating speed in the engine, an asymmetric turbocharger is proposed in 1978 by Cummins, and an inner flow passage of a turbine volute is designed to be large and small. In actual use, the inlet of the EGR loop is arranged only in front of the inlet of the small runner, and the sufficient EGR flow is introduced into an engine intake manifold at low rotating speed by utilizing the small runner with small flow capacity and high vortex front pressure. In order to prevent engine exhaust section leakage and turbine overspeed at medium and high rotation speeds, a waste gate valve is arranged at the turbine inlet, and the waste gate valve is opened to reduce the pressure in front of the turbine inlet. This results in energy loss due to the bleed air, which is detrimental to the improvement of the fuel economy of the engine.

The invention discloses a CN108087108 patent, and discloses a natural gas engine exhaust gas bypass type supercharger control system and a method thereof, and referring to fig. 1, the control system can open a supercharger bypass valve at the partial load of an engine, reduce the supercharging pressure, reduce the intake throttling resistance loss and improve the fuel economy. The method has the disadvantages that the supercharging pressure meets the working condition of the engine in a waste gas bypass mode, but part of high-temperature and high-pressure gas is discharged, so that energy loss is caused, and the heat efficiency of the engine is reduced.

The balance valve in the asymmetric supercharger is a little patented and mostly structurally innovative patent, and the patent is rarely related to a control system and a control method.

Disclosure of Invention

The invention provides a balance valve control system of an asymmetric turbocharger of an engine and a method thereof aiming at solving the problems that: 1. when the boost pressure far exceeds the target boost pressure, the energy loss caused by a waste gas bypass mode is avoided; 2. under partial working conditions, the full opening of the EGR valve still cannot meet the NO requirement_XWhen the emission requirement is met, the aims of increasing EGR and reducing emission can be achieved by controlling the opening degree of the balance valve. 3. The opening of the balance valve CAN be freely controlled based on CAN communication by adopting the independently developed balance valve control valve; and the control valve has a pressure maintaining function, so that the use amount of compressed air of the compressed air tank can be reduced.

In order to solve the technical problems, the invention is realized by adopting the following technical scheme, which is described by combining the accompanying drawings as follows:

a balance valve control system of an asymmetric turbocharger comprises a compressed air storage tank 1, a balance valve control valve 2, an engine control unit 3, a supercharging pressure sensor 4, a supercharger balance valve control diaphragm valve 5, a balance valve plate 6, a supercharger turbine 7 and a supercharger compressor 8;

the engine control unit 3 is connected with the boost pressure sensor 4 and the balance valve control valve 2;

the left channel of the balance valve control valve 2 is communicated with the atmosphere, the right channel is an air outlet and is connected with the booster balance valve control diaphragm valve 5, and the lower channel is an air inlet and is connected with the compressed air tank 1;

the supercharging pressure sensor 4 is arranged on an engine air inlet pipeline in front of a throttle valve; the booster balance valve control diaphragm valve 5 is connected with a booster balance valve plate 6, the opening degree of the booster balance valve plate 6 is controlled through the outlet air pressure of the balance valve control valve 2, and the pressure of asymmetrical large and small flow passages in front of the booster turbine 7 is controlled; the supercharger compressor 8 is connected with the supercharger turbine 7 through a rotating shaft.

In the technical scheme, the engine control unit 3 is connected with the boost pressure sensor 4 and the balance valve control valve 2, and is used for controlling the output pressure of the balance valve control valve 2 based on the pressure data acquired by the boost pressure sensor 4 so as to realize the opening control of the booster balance valve sheet 6.

In the technical scheme, the turbocharger turbine 7 adopts an asymmetric double-flow-channel structure and is matched with the balance valve control valve 2 for use, so that the opening degree of the balance valve plate 6 can be adjusted randomly.

A method of controlling a balanced valve control system for an asymmetric turbocharger comprising the steps of:

step 1, in the running process of an engine, an engine control unit 3 collects actual supercharging pressure and EGR rate according to a preset sampling frequency;

step 2, the engine control unit 3 compares the actual supercharging pressure and the EGR rate with target supercharging pressure and EGR rate to determine whether to adjust or not based on the collected actual supercharging pressure and EGR rate;

step 3, if the adjustment is not needed, jumping to step 9; if the adjustment is needed, determining the target outlet air pressure of the balance valve control valve, transmitting the target outlet air pressure to the balance valve control valve 2, and executing the step 4;

step 4, the balance valve control valve 2 determines a duty ratio according to the target outlet air pressure, adjusts the outlet air pressure, and feeds back the actual outlet air pressure to the engine electronic control unit 3 after the adjustment is finished;

step 5, the adjusted actual outlet air pressure of the balance valve control valve 2 acts on the pressurization balance valve control diaphragm valve 5, so that a valve core of the pressurization balance valve control diaphragm valve 5 moves;

step 6, the movement of the valve core of the supercharging balance valve control diaphragm valve 5 enables the opening of a balance valve plate 6 to change, and the output work and the preswirl pressure of the supercharger turbine 7 are caused to change;

step 7, changing the output work of the supercharger turbine 7 changes the work amount of the air compressor on the air, and further changes the supercharging pressure;

step 8, changing the boost pressure and the preswirl pressure of the turbocharger turbine 7 changes the engine EGR rate;

and 9, ending.

The step 4 specifically comprises the following steps:

1) comparing the target outlet air pressure with the actual outlet air pressure to obtain a deviation between a required outlet air pressure and an actual outlet air pressure;

2) determining a calculated value of a demand solenoid valve duty cycle 1 based on the demand outlet air pressure;

3) determining a calculated value 2 of the duty ratio of the demand solenoid valve based on a deviation between the demand outlet air pressure and the actual outlet air pressure;

4) and a sum obtained by adding the determined calculated value 1 and the calculated value 2 is used as the duty ratio of the demand solenoid valve.

The calculated value 1 is obtained by an open-loop control method, specifically by looking up a characteristic table of a control valve of the balance valve;

the balance valve control valve characteristic table is a final control characteristic table determined through calibration tests in the engine development process.

The open-loop control algorithm specifically comprises the following contents:

and under different inlet pressures of the balance valve control valve, obtaining different outlet air pressures through different three-way electromagnetic valve openness, thus obtaining a balance valve control valve characteristic table.

The calculated value 2 is calculated by a PID (proportional integral derivative) closed-loop feedback control algorithm in a preset period according to the deviation between the required outlet air pressure and the actual outlet air pressure, and the calculated value 2 calculated by the PID closed-loop feedback control algorithm is also called a feedback control value.

In the technical scheme, the preset period is 10 ms.

In the step 1, the preset sampling frequency is 50 Hz.

Compared with the prior art, the invention has the beneficial effects that:

1. energy loss caused by a waste gas bypass mode is avoided;

2. under partial working conditions, the full opening of the EGR valve still cannot meet the NO requirement_XWhen the emission requirement is met, the purposes of increasing EGR and reducing emission can be achieved by reducing the opening degree of the balance valve.

3. Free control of the opening of the balance valve CAN be realized based on CAN communication; 4. the use amount of the compressed air tank is reduced, and the energy consumption is reduced.

In conclusion, the invention can avoid the insufficient utilization of the exhaust energy by adopting the exhaust gas bypass type supercharger; the EGR rate of the engine at low rotating speed is ensured, the NOx generation amount is reduced, the pre-vortex pressure and the engine exhaust loss at medium and high rotating speeds are reduced, and the economic performance and the environmental performance of the engine are improved.

Drawings

The invention is further described with reference to the accompanying drawings in which:

FIG. 1 is a schematic diagram of a natural gas engine exhaust gas bypass supercharger control system and method;

FIG. 2 is a schematic diagram of a balancing valve control system of an asymmetric turbocharger for an engine according to the present invention;

FIG. 3 is a schematic view of a balanced valve control valve;

FIG. 4 is a schematic diagram of the configuration of the balanced valve control valve when increasing the control chamber pressure;

FIG. 5 is a schematic structural diagram of a balanced valve control valve when the pressure in the control chamber is stable;

FIG. 6 is a flow chart of a control method of a balance valve control system of an asymmetric turbocharger according to the present invention;

in the figure: 1. a compressed air storage tank; 2. a balance valve control valve; 3. an engine control unit; 4. a boost pressure sensor; 5. the booster balance valve controls the diaphragm valve; 6. a balance valve plate; 7. a supercharger turbine; 8. a supercharger compressor;

2-2, a proportional solenoid valve assembly; 2-3, a core assembly; 2-4, a valve body; 2-5, valve cover; 2-6, a microcontroller; 2-7, sealing the plug; 2-8, a gas pressure sensor; 2-9, an exhaust valve; 2-10, a gas release plug; 2-11, CAN communication connector; 2-12, pins; 2-13, a microcontroller cavity; 2-14, sealing rings; 2-15, sealing gasket;

2-21, a coil; 2-22, a static armature; 2-23, moving armature; 2-24, a top rod; 2-25, a return spring;

2-28, sealing ring;

2-31, valve core; 2-32, valve core seat; 2-33, a spool spring;

2-38, an air inlet cavity; 2-39, an exhaust cavity; 2-40, a control cavity;

2-41, an air inlet; 2-42, exhaust port; 2-43, a control port; 2-44, lumen; 2-45 and a sensor port.

Detailed Description

The invention is described in detail below with reference to the attached drawing figures:

the invention provides a balance valve control system of an asymmetric turbocharger of an engine, which is shown in figure 2. The system comprises a compressed air storage tank 1, a balance valve control valve 2, an engine control unit 3, a supercharging pressure sensor 4, a supercharger balance valve control diaphragm valve 5, a balance valve plate 6, a supercharger turbine 7 and a supercharger compressor 8.

The compressed air storage tank 1 stores high-pressure gas which is used as a power source; the balance valve control valve 2 is provided with a control valve and has the functions of pressure reduction, pressure stabilization and pressure detection, wherein the left channel of the balance valve control valve 2 is communicated with the atmosphere, the right channel is an air outlet and is connected with the balance valve control diaphragm valve 5 of the supercharger, and the lower channel is an air inlet and is connected with the compressed air tank 1;

the supercharging pressure sensor 4 is arranged on an engine air inlet pipeline in front of a throttle valve and used for measuring the supercharging pressure after being supercharged by the supercharger compressor; the booster balance valve control diaphragm valve 5 is connected with the booster balance valve plate 6 and used for controlling the opening degree of the booster balance valve plate 6 (the booster balance valve plate is in an open state under a normal state) through the outlet air pressure of the balance valve control valve 2 so as to control the pressure of asymmetrical large and small flow passages in front of the booster turbine 7. The supercharger compressor 8 is connected with the supercharger turbine 7 through a rotating shaft, and the turbine transmits work to the compressor through the shaft.

The balanced valve control valve 2 is a completely autonomous development, as shown in fig. 3. The valve comprises a proportional solenoid valve component 2-2, a valve core component 2-3, a valve body 2-4, a valve cover 2-5, a microcontroller 2-6, a sealing plug 2-7, a gas pressure sensor 2-8, an exhaust valve 2-9, an air relief plug 2-10 and a CAN communication connector 2-11;

proportional solenoid valve subassembly: 2-21 parts of coil, 2-22 parts of static armature, 2-23 parts of moving armature, 2-24 parts of ejector rod, 2-25 parts of return spring and 2-28 parts of sealing ring;

the valve core assembly: 2-31 parts of a valve core, 2-32 parts of a valve core seat and 2-33 parts of a valve core spring;

the microcontroller 2-6 is provided with a sealing ring 2-14;

the valve body 2-4 is provided with an air inlet 2-41, an air outlet 2-42, a control port 2-43, an inner cavity 2-44 and a sensor port 2-45;

the valve covers 2-5 are provided with: 2-15 parts of a sealing gasket;

additionally, pins 2-12 and a microcontroller cavity 2-13 are arranged;

the working principle is as follows:

when the engine is stopped, the proportional solenoid valve component 2-2 is in a power-off state, the movable armature 2-23 is far away from the static armature 2-22 under the action of the return spring 2-25, so that the sealing plug 2-7 is driven to be separated from the valve core 2-31, and the valve core is pressed on the valve core seat 2-32 by the valve core spring 2-33. At this time, compressed air is sealed in the air inlet cavity 2-38, the control cavity 2-40 is communicated with the air outlet cavity 2-39 through the middle hole of the valve core 2-31, the pressure in the cavity is close to zero, the valve plate of the balance valve is fully opened, and the large flow passage and the small flow passage are completely communicated, as shown in fig. 3.

When the operation condition of the engine changes, the engine control unit calculates a required target value of the opening degree of the valve plate of the balance valve according to the actual operation condition, and sends the target value to the microprocessor 2-6 of the device through CAN communication, the microprocessor 2-6 finds out the control cavity pressure corresponding to the value according to the preset calibration data, and then determines whether the control cavity pressure needs to be increased or decreased according to the current control cavity pressure fed back by the gas pressure sensor 2-8.

If the opening degree of a valve plate of the balance valve needs to be reduced, namely the pressure of a pressurization control cavity, the microcontroller 2-6 determines the duty ratio of a PWM (pulse-width modulation) driving signal of the proportional solenoid valve component 2-2 according to the difference between the target control cavity pressure and the current control cavity pressure, controls the static armature 2-22 of the proportional solenoid valve to generate certain suction force on the movable armature 2-23, and enables the movable armature 2-23 to prop open the valve core 2-31 for a certain distance through the ejector rod 2-24 and the sealing plug 2-7. At this time, the air inlet cavity 2-38 is communicated with the control cavity 2-40, the control cavity 2-40 is separated from the air exhaust cavity 2-39 by the sealing plug 2-7, the pressure of the control cavity rises, and as shown in fig. 4, the opening degree of the valve plate of the balance valve begins to decrease.

When the gas pressure sensor 2-8 detects that the pressure of the control cavity reaches a target value, the microcontroller 2-6 reduces the duty ratio of the proportional solenoid valve component 2-2 to a certain value, the electromagnetic force is reduced to a certain value (smaller than the spring force of the valve core, but larger than the pressure of the gas of the control cavity to the sealing plug), the valve core 2-31 is pressed back to the valve core seat 2-32 by the valve core spring 2-33, and the sealing plug 2-7 can still be pressed against the valve core 2-31 by the electromagnetic force. At this time, the intake chambers 2 to 38, the exhaust chambers 2 to 39, and the control chambers 2 to 40 are isolated from each other, and the control chamber pressure is stabilized, as shown in fig. 5, so that the valve sheet of the balance valve is maintained at a constant opening degree.

If the opening degree of a valve plate of the balance valve needs to be increased, namely the pressure of the control cavity is reduced, the microcontroller 2-6 reduces the duty ratio of the proportional solenoid valve component 2-2 to a certain value according to the pressure difference between the current control cavity pressure and the target control cavity, the electromagnetic force is reduced to a certain value (smaller than the pressure of the gas in the control cavity to the sealing plug), the gas pressure in the control cavity 2-40 pushes the sealing plug 2-7 away, the gas enters the exhaust cavity 2-39, the exhaust valve 2-9 is pushed to be opened and connected with the outside, the pressure in the control cavity is reduced, and the opening degree of the bypass valve is reduced. When the pressure of the control cavity reaches a target value, the microcontroller 2-6 increases the duty ratio of the proportional solenoid valve component 2-2 to a certain value again (smaller than the spring force of the valve core, but larger than the pressure of the gas of the control cavity to the sealing plug), the sealing plug 2-7 props against the valve core 2-31 again, the control cavity 2-40 is isolated from the exhaust cavity 2-39, and the pressure of the control cavity enables the valve block of the balance valve to be maintained at a corresponding opening degree.

The autonomously developed balanced valve control valve 2 has features and advantages including:

1. the opening of the valve plate of the balance valve is adjusted by adjusting the gas pressure of the control cavity through the proportional solenoid valve, so that the control is accurate and the cost is low;

2. the pressure reducing device has the pressure reducing function, a pressure valve is omitted from a pipeline system, and the cost of system components is reduced;

3. the pressure maintaining function is realized, a large amount of compressed air is not consumed, and the fuel economy of the engine is improved;

4. control chamber pressure closed loop control. When the pressure of the control cavity is reduced due to leakage or other disturbances, the microcontroller can increase the duty ratio in real time according to the current pressure of the control cavity detected by the gas pressure sensor to pressurize the control cavity, so that the pressure of the control cavity is always stabilized at a certain value, and the accuracy of controlling the opening degree of the valve plate of the balance valve is improved.

5. Calibration data of the corresponding relation between the opening of the valve plate of the balance valve and the pressure of the control cavity and calculation of the driving duty ratio of the proportional solenoid valve are transferred to the microcontroller, so that the workload of an engine control unit is reduced, the response speed of the valve plate of the balance valve in opening and closing is increased, and the response speed of the supercharger is increased.

6. The microcontroller has a CAN communication function, exchanges data with the engine control unit in real time, and ensures the rapidity and the real-time performance of signal processing. The CAN communication has the advantages of high reliability, perfect diagnosis and protection functions, wide applicability and the like, and improves the maintainability and the applicability of the supercharger balance valve control device.

The engine control unit 3 is connected with the boost pressure sensor 4 and the balance valve control valve 2, and is used for controlling the output pressure of the balance valve control valve 2 based on the pressure data acquired by the boost pressure sensor 4 so as to realize the opening control of the booster balance valve sheet 6.

The turbocharger turbine 7 adopts an asymmetric double-flow-channel structure, is matched with the balance valve control valve 2 for use, and can realize the random adjustment of the opening degree of the balance valve plate 6. Based on a certain control strategy, the pressures in front of a large flow channel and a small flow channel of the turbocharger are adjusted, the EGR rate of the engine at low rotating speed can be improved, and meanwhile, the deterioration of fuel economy caused by overhigh pressure in front of a vortex at high speed in the engine is avoided.

When the boost pressure measured by the boost pressure sensor 4 exceeds the pressure required by the current load, the valve plate 6 of the balance valve of the booster is properly closed, at the moment, the pressure of the front small runner of the turbine 7 of the booster is increased, the pressure of the large runner is decreased, the working capacity of the turbine 7 of the booster is decreased, the air inlet capacity of the compressor 8 of the booster is further decreased, and the boost capacity meets the requirement.

In addition, when the engine control unit 3 feeds back that the EGR of the engine system is insufficient (the EGR valve is fully opened, and the EGR rate of the engine system is still lower than the target value), the valve plate 6 of the balance valve of the supercharger is closed properly, so that the pressure of the front small flow passage of the turbine 7 of the supercharger rises, the flow of the EGR pipeline increases, and the EGR rate of the system is increased.

It should be noted that, in the present system, no matter the problem of excess of boost pressure or insufficient EGR is solved, the problem is solved by calibrating the target boost pressure of each working condition of the engine system in advance and presetting a target boost pressure control table in the engine control unit or the microprocessor.

A method of controlling a balanced valve control system for an asymmetric turbocharger comprising the steps of:

step 1, performing end touch on the performance of the engine, and calibrating the target boost pressure of each working condition of the engine system in advance to preset a target boost pressure control table in an engine control unit 3 in order to avoid the problems of excess boost pressure and insufficient EGR under partial working conditions.

Step 2, in the running process of the engine, the engine control unit 3 collects the supercharging pressure and the EGR rate according to a preset sampling frequency (such as 50Hz), and respectively compares the supercharging pressure and the EGR rate with a target supercharging pressure and an EGR rate to judge whether the balance valve needs to be adjusted, if so, the target value of the outlet pressure of the balance valve control valve is calculated, and if not, the control flow is ended;

step 3, the engine control unit 3 transmits a target value of the outlet pressure of the balance valve control valve to the balance valve control valve 2;

step 4, the balance valve control valve 2 sets a duty ratio according to the target value of the outlet pressure, and adjusts the outlet air pressure;

step 5, the balance valve control valve 2 judges whether the outlet air pressure reaches a set target or not, if not, the step 4 is returned,

step 6, the balance valve control valve 2 feeds the regulated outlet pressure back to the engine control unit 3;

step 7, the adjusted outlet pressure of the balance valve control valve 2 pushes the booster balance valve control diaphragm valve 5 to move;

step 8, the balance valve diaphragm valve 5 of the supercharger balance valve drives the balance valve plate 6 to move, the opening degree of the balance valve plate 6 changes, and the supercharging pressure and the EGR rate change;

and 9, ending.

The working principle of the balance valve control system of the asymmetric turbocharger provided by the embodiment is as follows:

the high-pressure air from the compressed air storage tank 1 for vehicle braking is sent to the balance valve control valve 2 through a pipeline, the air pressure entering the supercharger balance valve control diaphragm valve 5 through the balance valve control valve is controlled through the duty ratio of the balance valve control valve, the air pressure value is transmitted to the engine electric control unit 3, when the pressure acting on the diaphragm of the supercharger balance valve control diaphragm valve 5 is larger than the elastic force of a spring on the right side of the supercharger balance valve control diaphragm valve 5, the push rod of the supercharger balance valve control diaphragm valve 5 is pushed, the push rod closes the balance valve block 6 through a lever transmission structure, and the engine control unit 3 can control the opening degree of the balance valve block 6 by controlling the air pressure of the outlet of the balance valve control valve in the balance valve control valve 2.

Fig. 2 shows a balance valve control system of an asymmetric turbocharger of an engine, a system arrangement and a structure and a function of an autonomous balance valve control valve included in the system are described in the foregoing.

High-pressure air from a compressed air cylinder 1 for vehicle braking is delivered to a balance valve control valve 2 after passing through a pipeline, the opening of an electromagnetic valve on the balance valve control valve is controlled to control the air pressure flowing through the balance valve control valve to enter a supercharger balance valve control diaphragm valve 5, when the pressure acting on a diaphragm in the supercharger balance valve control diaphragm valve is larger than the elastic force of a spring on the right side of the diaphragm, a push rod of the supercharger balance valve control diaphragm valve is pushed, and the push rod changes the opening of the supercharger balance valve 6 through a lever structure. The engine control unit 3 sets the air pressure at the outlet of the balance valve control valve, and the balance valve control valve 2 completes adjustment, so that the control of the opening degree of the valve plate of the balance valve of the supercharger can be realized. The engine control unit 3 controls the opening degree of the balance valve sheet 6 based on the pressure data collected by the boost pressure sensor, and specifically comprises the following steps:

step 1, performing end touch on the performance of the engine, and calibrating the target boost pressure of each working condition of the engine system in advance to preset a target boost pressure control table in an engine control unit 3 in order to avoid the problems of excess boost pressure and insufficient EGR under partial working conditions.

Step 2, in the running process of the engine, the engine control unit 3 collects the supercharging pressure and the EGR rate according to a preset sampling frequency (such as 50Hz), and respectively compares the supercharging pressure and the EGR rate with a target supercharging pressure and an EGR rate to judge whether the balance valve needs to be adjusted, if so, the target value of the outlet pressure of the balance valve control valve is calculated, and if not, the control flow is ended;

step 3, the engine control unit 3 transmits a target value of the outlet pressure of the balance valve control valve to the balance valve control valve 2;

step 4, the balance valve control valve 2 sets a duty ratio according to the target value of the outlet pressure, and adjusts the outlet air pressure;

step 5, the balance valve control valve 2 judges whether the outlet air pressure reaches a set target or not, if not, the step 4 is returned,

step 6, the balance valve control valve 2 feeds the regulated outlet pressure back to the engine control unit 3;

step 7, the adjusted outlet pressure of the balance valve control valve 2 pushes the booster balance valve control diaphragm valve 5 to move;

step 8, the balance valve diaphragm valve 5 of the supercharger balance valve drives the balance valve plate 6 to move, the opening degree of the balance valve plate 6 changes, and the supercharging pressure and the EGR rate change;

and 9, ending.

Further, step 4 may specifically include the following steps:

1) comparing the required outlet air pressure with the actual outlet air pressure to obtain a deviation between the required outlet air pressure and the actual outlet air pressure.

2) A calculated value 1 of the duty cycle of the demand solenoid valve is determined based on the demand outlet air pressure.

In this step, the calculated value 1 can be obtained by an open loop control method, specifically by looking up a table of characteristics of the balanced valve control valve. The control of the duty ratio of the electromagnetic valve required by the balance valve control valve is only the air inlet and exhaust pressure characteristics of the balance valve control valve, different air pressure values at the outlet of the balance valve control valve are obtained by giving different electromagnetic valve duty ratios under the inlet pressure of a certain balance valve control valve, and the control calibration can be carried out on a balance valve control valve test bed regardless of the running working condition of an engine. The open-loop control algorithm of the electromagnetic valve of the balance valve control valve is essentially the basic flow characteristic of the three-way electromagnetic valve, under different inlet pressures of the balance valve control valve, different opening degrees of the three-way electromagnetic valve are obtained to obtain different outlet air pressures, so that a balance valve control valve characteristic table is obtained, in actual operation, the inlet pressure of the three-way electromagnetic valve is a constant value, when a required outlet air pressure is given, the opening degree of the three-way electromagnetic valve is obtained by checking the balance valve control valve characteristic table, namely the open-loop control algorithm, and by using the open-loop control algorithm, the opening degree of the three-way electromagnetic valve can be opened to be close to a stable value as soon as possible.

3) Based on the deviation between the required outlet air pressure and the actual outlet air pressure, a calculated value 2 of the required solenoid valve duty ratio is determined.

In this step, the calculated value 2 may be calculated by an algorithm of PID closed-loop feedback control at a calculation period of a preset period, for example, 10ms, according to a deviation between the required outlet air pressure and the actual outlet air pressure. The calculated value 2 calculated by the algorithm of the PID closed-loop feedback control is also referred to as a feedback control value. In this embodiment, the closed-loop feedback control algorithm for calculating the feedback control value is an anti-saturation PID control algorithm, the PID control algorithm obtains a closed-loop feedback control value according to a difference between the required outlet air pressure and the actual outlet air pressure and according to a proportional, integral, and derivative algorithm, and the closed-loop feedback control algorithm contributes to the stabilization of the actually output outlet air pressure.

4) And a sum obtained by adding the determined calculated value 1 and the calculated value 2 is used as the duty ratio of the demand solenoid valve.

That is, the required solenoid valve duty ratio in this embodiment is obtained by open-loop control and closed-loop feedback control.

The control method is a flow chart, as shown in FIG. 6. Before the engine leaves the factory, a control table is preset in the engine control unit 3 to give target boost pressure and EGR rate required by the engine under different target operating parameters (such as rotating speed, fuel consumption output power and the like).

The control flow comprises the following steps:

determining whether the boost pressure and the EGR rate need to be controlled according to the current operation condition of the engine, and if so, executing the following steps:

step 1, in the running process of an engine, an engine control unit 3 collects supercharging pressure and EGR rate according to a preset sampling frequency (such as 50Hz), and respectively compares the supercharging pressure and the EGR rate with a target supercharging pressure and the EGR rate to judge whether a balance valve needs to be adjusted, if so, a target value of outlet pressure of a control valve of the balance valve is calculated, and if not, the control flow is ended;

step 2, the engine control unit 3 transmits a target value of the outlet pressure of the balance valve control valve to the balance valve control valve 2;

step 3, the balance valve control valve 2 sets a duty ratio according to the target value of the outlet pressure, and adjusts the outlet air pressure;

step 4, the balance valve control valve 2 judges whether the outlet air pressure reaches a set target or not, if not, the step 3 is returned,

step 5, the balance valve control valve 2 feeds the regulated outlet pressure back to the engine control unit 3;

step 6, the adjusted outlet pressure of the balance valve control valve 2 pushes the booster balance valve control diaphragm valve 5 to move;

step 7, the booster balance valve control diaphragm valve 5 drives the balance valve plate 6 to move, the opening degree of the balance valve plate 6 changes, and the boost pressure and the EGR rate change;

and 8, ending.

And those not described in detail in this specification are well within the skill of those in the art.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.