阅读说明：本技术 一种燃气热泵专用燃气发动机控制系统 (Special gas engine control system for gas heat pump ) 是由 邵传刚 冯自平 于 2021-01-15 设计创作，主要内容包括：本发明公开了一种燃气热泵专用燃气发动机控制系统,该系统可在燃气供给压力出现波动时通过燃气压力传感器检测出实际燃气压力并反馈给ECU从而调节燃气比例阀中的步进电机步数改变混合器的燃气进入量,达到燃气量的实时调节。同时根据氧传感器检测到的排气管中的氧含量判断燃气组分以及进行燃气供给量的实时修正,保持过量空气系数在目标值范围内,提高后处理的转化效率。电控高能独立点火系统,可根据发动机不同转速和负荷提供最佳点火能量和点火时刻,有效降低燃气消耗率、减少发动机污染物排放量。(The invention discloses a special gas engine control system for a gas heat pump, which can detect the actual gas pressure through a gas pressure sensor and feed back the actual gas pressure to an ECU (electronic control unit) when the gas supply pressure fluctuates, so that the step number of a stepping motor in a gas proportional valve is adjusted to change the gas inlet amount of a mixer, and the real-time adjustment of the gas amount is realized. Meanwhile, the components of the fuel gas are judged according to the oxygen content in the exhaust pipe detected by the oxygen sensor, the supply quantity of the fuel gas is corrected in real time, the excess air coefficient is kept within a target value range, and the conversion efficiency of aftertreatment is improved. The electric control high-energy independent ignition system can provide the optimal ignition energy and the ignition time according to different rotating speeds and loads of the engine, effectively reduce the gas consumption rate and reduce the pollutant discharge amount of the engine.)

1. A special gas engine control system for a gas heat pump is characterized by comprising:

the gas pressure sensor and the gas proportional valve are used for being installed in a gas pipeline of the engine;

an oxygen sensor for installation in an engine exhaust conduit;

the ECU is respectively connected with the gas pressure sensor, the gas proportional valve and the oxygen sensor;

when the gas supply pressure fluctuates, the actual gas pressure is detected by the gas pressure sensor and fed back to the ECU, and the ECU adjusts the opening of the gas proportional valve to change the gas inlet amount of the mixer, so that the real-time adjustment of the gas amount and the air-fuel ratio is realized;

the oxygen sensor is used for detecting the oxygen content in the exhaust pipeline and feeding the oxygen content back to the ECU, and the ECU judges the gas components and adjusts the opening of the gas proportional valve to correct the gas supply in real time so as to keep the excess air coefficient within a target value range;

and the ECU is connected with a gas heat pump controller to exchange information in real time.

2. The gas engine control system special for a gas heat pump as claimed in claim 1, wherein the ECU exchanges information with the gas heat pump controller in real time through a CAN bus to control engine start, operation, speed regulation, protection, fault handling, and stop functions through the CAN bus.

3. The gas engine control system for a gas heat pump as recited in claim 1, further comprising:

the venturi mixer is provided with two air inlets, one air inlet is communicated with the air outlet end of the fuel gas proportional valve, and the other air inlet is an air inlet end so as to mix air and fuel gas into combustible mixed gas;

an air inlet of the electronic throttle valve is communicated with an outlet of the Venturi mixer, and an air outlet of the electronic throttle valve is communicated to an engine air inlet manifold; the ECU is connected with the electronic throttle valve to control the engine speed and the load by controlling the opening of the electronic throttle valve.

4. The gas engine control system for a gas heat pump according to claim 1 or 3, further comprising:

the air inlet temperature and pressure sensor is used for being installed in an engine air inlet manifold, collecting the temperature and pressure in the engine air inlet manifold and feeding back the air inlet amount of the combustible mixed gas of the engine to the ECU in real time;

the gas temperature and pressure sensor is arranged in a gas pipeline of the engine, and is used for collecting the temperature and pressure in the gas pipeline so as to feed back the gas supply quantity to the ECU in real time;

the ECU reflects the current actual air-fuel ratio in real time according to the feedback of the air inlet temperature pressure sensor and the gas pressure sensor, and the ECU controls the action of the gas proportional valve to achieve the purpose of controlling the amount of the entering gas.

5. The gas engine control system for a gas heat pump according to claim 3, further comprising:

and the crankshaft position sensor and the camshaft position sensor are used for detecting the corresponding relation between the current rotating speed of the engine and the crankshaft rotation angle of the piston from the top dead center and feeding back the corresponding relation to the ECU, and the ECU judges the best advance angle capable of being ignited.

6. The gas engine control system special for the gas heat pump as claimed in claim 5, wherein when the ECU receives a speed regulation request and a target rotating speed of the gas heat pump controller, the ECU controls the change of the opening degree of the electronic throttle valve so as to achieve the purpose of controlling the rotating speed of the engine; meanwhile, a crankshaft position sensor feeds back the real-time engine rotating speed, and the ECU adjusts the opening of the electronic throttle valve and the gas proportional valve according to a comparison value of the actual rotating speed and the target rotating speed so as to achieve the purpose of carrying out closed-loop control along with the target rotating speed.

7. The gas engine control system for a gas heat pump as recited in claim 1, further comprising:

the water temperature sensor and the engine oil temperature pressure sensor are used for detecting the water outlet temperature, the engine oil pressure and the temperature state of the engine, feeding the water outlet temperature, the engine oil pressure and the temperature state back to the ECU and providing input information for correcting the gas quantity, the combustible mixed gas air inflow and the ignition advance angle for the ECU; when the water temperature exceeds the standard, the oil temperature exceeds the standard, and the engine oil pressure is too low and too high, the data is fed back to the ECU to make active protection actions of the engine, including rotating speed reduction, load reduction or shutdown.

8. The gas engine control system for a gas heat pump as recited in claim 5, wherein said oxygen sensor comprises an upstream oxygen sensor and a downstream oxygen sensor;

the upstream oxygen sensor is used for detecting the exhaust oxygen concentration in front of a three-way catalytic converter in an exhaust pipeline of the engine in real time and feeding the exhaust oxygen concentration back to the ECU, and the ECU continuously adjusts the gas flow and corrects the opening of an electronic throttle valve and the ignition advance angle according to the change of the air-fuel ratio to achieve a closed loop state taking equivalence ratio combustion as a control target all the time;

the downstream oxygen sensor is used for detecting the change of the exhaust oxygen concentration behind the three-way catalyst, monitoring the working capacity of the three-way catalyst in real time, feeding back the state of the three-way catalyst and inputting effective information for ECU emission control.

9. The gas engine control system for a gas heat pump according to claim 3, further comprising:

and the air outlet of the air filter is communicated with the air inlet end of the Venturi mixer.

10. The gas engine control system special for the gas heat pump as claimed in claim 1, further comprising a gas filter and a gas solenoid valve installed in a gas pipeline of the engine, wherein the gas solenoid valve is controlled by the ECU, and the pipeline gas passes through the gas solenoid valve after passing through the gas filter.

Technical Field

The invention belongs to the technical field of gas heat pump air conditioners, and relates to an engine gas supply control system of a gas engine driven air conditioning unit.

Background

At present, as for a gas engine driven air-conditioning heat pump unit (GHP, gas heat pump), a mechanical proportional mixer and an oxygen-free sensor are adopted in an engine gas supply system for closed-loop control, and an ECU control system is not provided. The gas quantity regulation, the electric control ignition and the throttle opening control are relatively independent systems. The self-adaptive air-fuel ratio adjustment and correction can not be carried out according to the components and the pressure of the fuel gas, and the defects of large fuel gas consumption, low heat efficiency, high pollutant emission and the like exist. The air-fuel ratio cannot be accurately controlled when the gas component in the supply pipeline changes and the pressure fluctuates. When the methane content of the combustion gases and the pressure of the combustion gases decrease, which may cause excessive air supply, the three-way catalyst (TWC) may not effectively treat Nitrogen Oxides (NO) in the exhaust gases_X)，NO_XThe emission is out of standard. When the methane content and the gas pressure in the gas are increased, the supplied air amount is insufficient, the mixed gas is too rich, the conversion efficiency of carbon monoxide (CO) and Hydrocarbon (HC) is reduced, the emission exceeds the standard, the economy is reduced, meanwhile, a large amount of reducing agents can be generated in the exhaust gas passing through a three-way catalyst (TWC), and the atomic ammonia generated by the dissociation of the nitrogen monoxide (NO) is reduced to generate ammonia (HN)₃) I.e. new contaminants are generated. Because the conversion efficiency of the three-way catalyst is closely related to the excess air coefficient of the engine, the three-way catalyst can simultaneously purify CO, HC and NO_XThe narrow window of the excess air ratio of more than 80% of the three pollutants is about 0.985-1.005, so the control of the excess air ratio 1 (theoretical air-fuel ratio) is required as a target, but the current control scheme of the mechanical proportional mixer cannot meet the control precision requirement. In the case of gas engines seeking high economy, power and low emissions, new control systems must be applied.

The gas engine driven air-conditioning heat pump unit (GHP) takes urban pipeline natural gas as fuel, and the gas supply pressure is about 1.0-2.5 kPa and is slightly higher than the atmospheric pressure. Since a fuel supply scheme cannot be performed by a gas injector with respect to a gas pressure of 100 to 500kPa obtained by pressure-regulating a Compressed Natural Gas (CNG) and a Liquefied Natural Gas (LNG) for a vehicle by a pressure-reducing valve, a conventional gas supply system for a vehicle cannot be used for performing high-precision control, and for example, a natural gas engine control and fuel supply system and method which are disclosed in patent document CN104696085A, cannot be used.

Disclosure of Invention

In order to solve at least one technical problem in the background art, the invention provides a gas engine control system special for a gas heat pump.

In order to achieve the purpose, the technical scheme of the invention is as follows:

a gas engine control system special for a gas heat pump comprises:

the gas pressure sensor and the gas proportional valve are used for being installed in a gas pipeline of the engine;

an oxygen sensor for installation in an engine exhaust conduit;

the ECU is respectively connected with the gas pressure sensor, the gas proportional valve and the oxygen sensor;

when the gas supply pressure fluctuates, the actual gas pressure is detected by the gas pressure sensor and fed back to the ECU, and the ECU adjusts the opening of the gas proportional valve to change the gas inlet amount of the mixer, so that the real-time adjustment of the gas amount and the air-fuel ratio is realized;

the oxygen sensor is used for detecting the oxygen content in the exhaust pipeline and feeding the oxygen content back to the ECU, and the ECU judges the gas components and adjusts the opening of the gas proportional valve to correct the gas supply in real time so as to keep the excess air coefficient within a target value range;

and the ECU is connected with a gas heat pump controller to exchange information in real time.

Furthermore, the ECU and the gas heat pump controller exchange information in real time through a CAN bus so as to control the functions of starting, running, speed regulation, protection, fault treatment and shutdown of the engine through the CAN bus.

Further, the gas engine control system dedicated for the gas heat pump further includes:

the venturi mixer is provided with two air inlets, one air inlet is communicated with the air outlet end of the fuel gas proportional valve, and the other air inlet is an air inlet end so as to mix air and fuel gas into combustible mixed gas;

an air inlet of the electronic throttle valve is communicated with an outlet of the Venturi mixer, and an air outlet of the electronic throttle valve is communicated to an engine air inlet manifold; the ECU is connected with the electronic throttle valve to control the engine speed and the load by controlling the opening of the electronic throttle valve.

Further, the gas engine control system dedicated for the gas heat pump further includes:

the air inlet temperature and pressure sensor is used for being installed in an engine air inlet manifold, collecting the temperature and pressure in the engine air inlet manifold and feeding back the air inlet amount of the combustible mixed gas of the engine to the ECU in real time;

the gas temperature and pressure sensor is arranged in a gas pipeline of the engine, and is used for collecting the temperature and pressure in the gas pipeline so as to feed back the gas supply quantity to the ECU in real time;

the ECU reflects the current actual air-fuel ratio in real time according to the feedback of the air inlet temperature pressure sensor and the gas pressure sensor, and the ECU controls the action of the gas proportional valve to achieve the purpose of controlling the amount of the entering gas.

Further, the gas engine control system dedicated for the gas heat pump further includes:

a crankshaft position sensor and a camshaft position sensor for detecting the corresponding relation between the current rotation speed of the engine and the crankshaft rotation angle of the piston from the top dead center and feeding back to the ECU, and the ECU judges the best advance angle for ignition

Further, when the ECU receives a speed regulation request and a target rotating speed of the gas heat pump controller, the opening of the electronic throttle valve is controlled to change, so that the aim of controlling the rotating speed of the engine is fulfilled; meanwhile, a crankshaft position sensor feeds back the real-time engine rotating speed, and the ECU adjusts the opening of the electronic throttle valve and the gas proportional valve according to a comparison value of the actual rotating speed and the target rotating speed so as to achieve the purpose of carrying out closed-loop control along with the target rotating speed.

Further, the gas engine control system dedicated for a gas heat pump is characterized by further comprising:

the water temperature sensor and the engine oil temperature pressure sensor are used for detecting the water outlet temperature, the engine oil pressure and the temperature state of the engine, feeding the water outlet temperature, the engine oil pressure and the temperature state back to the ECU and providing input information for correcting the gas quantity, the combustible mixed gas air inflow and the ignition advance angle for the ECU; when the water temperature exceeds the standard, the oil temperature exceeds the standard, and the engine oil pressure is too low and too high, the data is fed back to the ECU to make active protection actions of the engine, including rotating speed reduction, load reduction or shutdown.

Further, the oxygen sensor comprises an upstream oxygen sensor and a downstream oxygen sensor;

the upstream oxygen sensor is used for detecting the exhaust oxygen concentration in front of a three-way catalytic converter in an exhaust pipeline of the engine in real time and feeding the exhaust oxygen concentration back to the ECU, and the ECU continuously adjusts the gas flow and corrects the opening of an electronic throttle valve and the ignition advance angle according to the change of the air-fuel ratio to achieve a closed loop state taking equivalence ratio combustion as a control target all the time;

the downstream oxygen sensor is used for detecting the change of the exhaust oxygen concentration behind the three-way catalyst, monitoring the working capacity of the three-way catalyst in real time, feeding back the state of the three-way catalyst and inputting effective information for ECU emission control.

Further, the gas engine control system dedicated for the gas heat pump further includes:

and the air outlet of the air filter is communicated with the air inlet end of the Venturi mixer.

Furthermore, the special gas engine control system for the gas heat pump further comprises a gas filter and a gas electromagnetic valve which are arranged in a gas pipeline of the engine, the work of the gas electromagnetic valve is controlled by the ECU, and the pipeline gas passes through the gas electromagnetic valve after passing through the gas filter.

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

the gas engine driven air-conditioning heat pump unit (gas heat pump) takes urban pipeline natural gas as fuel, and the gas supply pressure is about 1.0-2.5 kPa and is slightly higher than the atmospheric pressure. Compared with the gas pressure of 100-500 kPa after the pressure of Compressed Natural Gas (CNG) and Liquefied Natural Gas (LNG) for vehicles is regulated by a pressure reducing valve, a fuel supply scheme cannot be carried out by adopting a gas injector, so that the high-precision control cannot be carried out by utilizing the conventional gas supply system for vehicles. The invention aims at the problems that the gas pressure is low and the high-precision gas supply control of a gas heat pump cannot be realized by the existing mechanical proportional mixer, creatively adopts a gas proportional valve of a high-precision stepping motor with position feedback to carry out gas quantity regulation, a Venturi mixer and an electronic throttle valve combination, utilizes an oxygen sensor to detect the oxygen content in exhaust gas in real time to realize gas supply closed-loop control, adopts high-energy electric control independent ignition, has the functions of theoretical air-fuel ratio premixed combustion and lean combustion, and can reduce the system cost, improve the economy, improve the control precision of an excess air coefficient and effectively reduce pollutants discharged by a special engine for the gas heat pump.

Drawings

Fig. 1 is a schematic composition diagram of a gas engine control system dedicated for a gas heat pump according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a power supply and diagnosis part of a gas engine control system for a gas heat pump;

FIG. 3 is a schematic diagram of a sensor portion of a schematic circuit diagram of a gas engine control system dedicated for a gas heat pump;

FIG. 4 is a schematic diagram of a circuit schematic diagram actuator part of a gas engine control system dedicated for a gas heat pump;

in the figure: 1-an air filter; 2-a venturi mixer; 3-electronic throttle valve; 4-water temperature sensor; 5-intake air temperature pressure sensor; 6-engine oil temperature pressure sensor; 7-a crankshaft position sensor; 8-an engine; 9-a spark plug; 10-camshaft position sensor; 11-an upstream oxygen sensor; 12-a three-way catalyst; 13-a downstream oxygen sensor; 14-a gas proportional valve; 15-gas temperature pressure sensor; 16-a gas solenoid valve; 17-a gas filter; 18-ECU.

Detailed Description

Example (b):

in the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted" and "connected" are to be interpreted broadly, e.g., as being either fixedly connected, detachably connected, or integrally connected; the connection can be mechanical connection, electrical connection and signal connection; they may be connected directly or indirectly through intervening media, so to speak, as communicating between the two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art. The technical solution of the present invention is further described below with reference to the accompanying drawings and examples.

Referring to fig. 1 to 4, the control system of the gas engine 8 dedicated for the gas heat pump provided in the present embodiment mainly includes a gas pressure sensor 15 and a gas proportional valve 14, which are installed in a gas pipeline of the engine 8; an oxygen sensor for installation in an engine exhaust conduit; an ECU (Electronic Control Unit) 18 is connected to the gas pressure sensor 15, the gas proportional valve 14, and the oxygen sensor, respectively. Therefore, the control system of the special gas engine for the gas heat pump can detect the actual gas pressure through the gas pressure sensor 15 when the gas supply pressure fluctuates and feed back the actual gas pressure to the ECU18, so that the step number of the stepping motor in the gas proportional valve 14 is adjusted to change the gas inlet quantity, and the real-time adjustment of the gas quantity is realized; meanwhile, the gas components are judged according to the oxygen content in the exhaust pipe detected by the oxygen sensor, the gas supply quantity and the air-fuel ratio are corrected in real time, the excess air coefficient is kept within a target value range, and the conversion efficiency of post-treatment is improved.

The ECU18 is connected to the gas heat pump controller to exchange information in real time. Specifically, the ECU18 exchanges information with the gas heat pump controller in real time through the CAN bus to control the functions of engine start, operation, speed regulation, protection, fault treatment and shutdown through the CAN bus, thereby improving the control precision and reliability, reducing the gas consumption rate, reducing the use and maintenance cost, and integrating the engine and the gas heat pump system into a whole, namely, the gas engine control system special for the gas heat pump.

As a preferable aspect of this embodiment, the control system further includes:

the venturi mixer 2 is provided with two air inlets, one air inlet is communicated with the air outlet end of the fuel gas proportional valve 14, and the other air inlet is an air inlet end so as to mix air and fuel gas into combustible mixed gas;

an air inlet of the electronic throttle valve 3 is communicated with an outlet of the Venturi mixer 2, and an air outlet of the electronic throttle valve is communicated to an engine air inlet manifold;

the ECU18 is connected to the electronic throttle valve 3 to control the engine speed and load by controlling the opening of the electronic throttle valve 3.

Because the gas heat pump unit adopts pipeline natural gas, the gas pressure is lower, the gas injector can not be used for accurately controlling the gas supply quantity, and fresh air and gas are uniformly mixed and then are sucked into the cylinder through negative pressure generated in the cylinder and the gas inlet manifold when the engine is used for air inlet, and then are ignited through the spark plug. However, negative pressures generated by different engines under different working rotating speeds and air inlet pressure temperatures are different, so that a targeted mixer design must be carried out according to the characteristics of the displacement, the rotating speed and the negative pressure of the engines; when the air inlet pressure of the engine is close to the atmospheric pressure at full load and is very close to the gas supply pressure of the gas, the gas quantity is reduced by suction, the requirement that the gas supply quantity of the engine is increased at high load is not facilitated, the venturi tube can generate negative pressure at the position perpendicular to the throat, and the problem of reduction of gas quantity by suction can be effectively solved by connecting the venturi tube with a gas proportional valve (namely the gas outlet end of a gas pipeline).

The opening of the electronic throttle valve 3 can effectively control the fresh air entering the engine, so that the amount of combustible gas mixture entering the cylinder is controlled, and the purpose of controlling the revolution number and the output power of the engine is achieved by adjusting the opening of the electronic throttle valve.

Therefore, the control mode combining the Venturi mixer 2 and the electronic throttle valve 3 can enable gas and air to be uniformly mixed, the gas supply quantity demand is guaranteed, and the rotating speed and the load of the engine are controlled.

As another preferable aspect of this embodiment, the control system further includes:

the intake temperature and pressure sensor 5 is arranged in an engine intake manifold, and is used for collecting the temperature and pressure in the engine intake manifold so as to feed back the intake amount of the combustible mixed gas of the engine to the ECU18 in real time;

the fuel gas temperature and pressure sensor 15 is installed in a fuel gas pipeline of the engine, collects the temperature and pressure in the fuel gas pipeline and feeds back the fuel gas supply quantity to the ECU18 in real time;

the ECU18 reflects the current actual air-fuel ratio in real time according to the feedback of the air inlet temperature pressure sensor 5 and the gas pressure sensor 15, and the ECU18 controls the action of a gas proportional valve to achieve the purpose of controlling the amount of the entering gas.

As still another preferable aspect of this embodiment, the control system further includes:

and the crankshaft position sensor 7 and the camshaft position sensor 10 are used for detecting the corresponding relation between the current rotating speed of the engine and the crank angle of the piston from the top dead center, feeding the corresponding relation back to the ECU18, and judging the best advance angle capable of igniting by the ECU 18.

As still another preferable mode of the embodiment, when the ECU18 receives a speed regulation request and a target rotation speed from the gas heat pump controller, the ECU controls the opening degree of the electronic throttle valve 3 to change, so as to control the rotation speed of the engine; meanwhile, the crankshaft position sensor 7 feeds back real-time engine rotating speed, and the ECU18 adjusts the opening of the electronic throttle valve according to a comparison value of the actual rotating speed and the target rotating speed so as to achieve the purpose of carrying out closed-loop control along with the target rotating speed.

As still another preferable aspect of the present embodiment, the gas engine control system dedicated for a gas heat pump further includes:

the water temperature sensor 4 and the engine oil temperature pressure sensor 6 are used for detecting the water outlet temperature, the engine oil pressure and the temperature state of the engine, feeding the water outlet temperature, the engine oil pressure and the temperature state back to the ECU18 and providing input information for correcting the gas quantity, the combustible mixed gas intake quantity and the ignition advance angle for the ECU 18; when the water temperature exceeds the standard, the oil temperature exceeds the standard, and the engine oil pressure is too low and too high, the data is fed back to the ECU18 to make active protection actions of the engine, including rotating speed reduction, load reduction or shutdown, so that the reliability of the engine is improved, and the effective service life of the engine is prolonged.

The combustible mixed gas is combusted in the engine cylinder to generate high-temperature and high-pressure gas to push the piston to move so that the connecting rod pushes the crankshaft to rotate, and therefore the engine does work outwards. In order to ensure that the working softness and the power performance of the engine are good, the highest combustion explosion pressure needs to be controlled to be 12-15 degrees (CA) after the top dead center, so that the optimal ignition time is needed to ensure the occurrence time of the highest pressure. However, the combustion of the combustible mixture is related to the ignition energy, which is related to the magnetizing time of the ignition coil, and the service life of the ignition coil is influenced. There is therefore an optimum ignition energy and ignition moment.

The scheme of the invention for ensuring the optimal ignition energy and ignition time of the engine with different rotating speeds and loads comprises the following steps: the crankshaft position sensor and the camshaft position sensor acquire and feed back the corresponding relation between the current rotating speed of the engine and the crankshaft rotation angle of the piston from the top dead center in real time, and the best ignition advance angle is judged; the intake pressure and temperature sensor collects the pressure of an intake manifold of the engine, the pressure and the opening degree of the electronic throttle valve jointly judge the load size of the engine at the current rotating speed (the higher the intake pressure is, the larger the opening degree of the electronic throttle valve is, the larger the load is), and meanwhile, the current temperature and the current temperature of the cooling liquid and the actual air-fuel ratio fed back by the oxygen sensor can be collected to be corrected; in order to ensure sufficient and reliable ignition and prevent the occurrence of poor combustion phenomena such as knocking, early ignition and the like, ignition energy is controlled by controlling the magnetizing time of an ignition coil during ignition, so that the aim of having the optimal ignition energy and ignition time under different rotating speeds and loads is fulfilled.

Specifically, the above-described oxygen sensors include an upstream oxygen sensor 11 and a downstream oxygen sensor 13;

the upstream oxygen sensor 11 is used for detecting the exhaust oxygen concentration in the exhaust pipeline of the engine in real time before the three-way catalyst 12 and feeding the exhaust oxygen concentration back to the ECU18, and the ECU18 continuously adjusts the gas flow and corrects the opening of the electronic throttle valve 3 and the ignition advance angle according to the change of the air-fuel ratio to achieve a closed-loop state taking equivalence ratio combustion as a control target all the time;

the downstream oxygen sensor 13 is used for detecting the change of the exhaust oxygen concentration after the three-way catalyst 12, monitoring the working capacity of the three-way catalyst 12 in real time, feeding back the state of the three-way catalyst, effectively controlling the reduction of emissions, defining the emission state and inputting effective information for ECU emission control.

In addition, the gas engine control system special for the gas heat pump further comprises an air filter 1, a gas filter 17 and a gas electromagnetic valve 16. Fig. 1 shows an optimal control system diagram of a gas engine dedicated for a gas heat pump, which works on the principle that pipeline gas passes through a gas filter 17 and then passes through an electromagnetic valve 16, a gas temperature and pressure sensor 15 detects the gas state in real time and feeds back the gas state to an ECU18, the gas flow is controlled by a gas proportional valve 14, and then the gas and fresh air passing through an air filter 1 are uniformly mixed in a venturi mixer 2 to form combustible mixed gas. The combustible mixed gas enters an engine intake manifold after passing through the electronic throttle valve 3 and then enters a cylinder to be ignited by the spark plug 9, the high-temperature and high-pressure gas pushes the piston to move downwards, and the pressure applied to the top of the piston is transmitted to the connecting rod through the piston pin seat and the piston pin to push the crankshaft to rotate, so that the engine does work outwards. The combusted gas is exhausted to the three-way catalytic converter 12 through an exhaust pipe, more than 80 percent of pollutants are reduced into N₂、CO₂、HO₂And finally discharged to the atmosphere.

When the ignition switch is in an ON gear, the main relay is closed, the system is electrified, the gas electromagnetic valve is opened, and the control system enters a preparation state.

When the CAN bus receives a starting request signal of the gas heat pump host, the starting relay is controlled to be closed, the starter works, the engine is driven to reach a starting rotating speed (more than or equal to 120r/min), and the engine enters a starting state.

At the moment, the gas temperature and pressure sensor and the air inlet temperature and pressure sensor respectively detect gas flow and air intake, after the gas flow and the air intake are fed back to the ECU, the ECU controls the gas proportional valve to act, so that the purpose of controlling the gas intake, namely the air-fuel ratio, is achieved, meanwhile, the crankshaft position sensor and the camshaft position sensor detect the rotating speed of the engine and determine the actual working sequence and position of the cylinder to be fed back to the ECU, the ECU controls the ignition coil to ignite the cylinder before the compression top dead center, and the engine enters an idling state.

The rotating speed and the load of the engine 8 are controlled by the electronic throttle valve 3, when the ECU18 receives a speed regulation request of a CAN bus and a target rotating speed, the opening of the electronic throttle valve is controlled to change so as to achieve the purpose of controlling the rotating speed, meanwhile, the crankshaft position sensor feeds back the real-time rotating speed, and the ECU adjusts the opening of the electronic throttle valve and the gas proportional valve according to a contrast value of the actual rotating speed and the target rotating speed so as to achieve the purpose of carrying out closed-loop control along with the target rotating speed.

In conclusion, the special gas engine control system for the gas heat pump can detect the actual gas pressure through the gas pressure sensor when the gas supply pressure fluctuates and feed the actual gas pressure back to the ECU, so that the step number of the stepping motor in the gas proportional valve is adjusted to change the gas inlet amount of the mixer, and the real-time adjustment of the gas amount is achieved. Meanwhile, the components of the fuel gas are judged according to the oxygen content in the exhaust pipe detected by the oxygen sensor, the supply quantity of the fuel gas is corrected in real time, the excess air coefficient is kept within a target value range, and the conversion efficiency of aftertreatment is improved. The electric control high-energy independent ignition system can provide the optimal ignition energy and the ignition time according to different rotating speeds and loads of the engine, effectively reduce the gas consumption rate and reduce the pollutant discharge amount of the engine. Aiming at a special gas engine control system of a gas heat pump, the key innovation technical points are as follows:

(1) the device can adapt to pipeline gas with different gas pressures, and can effectively adjust the gas supply amount when the gas pressure fluctuates, so that the mixing ratio of the gas and fresh air is ensured;

(2) the device is suitable for different fuel gas components, the methane content of pipelines in different areas is different, closed-loop control is performed through an oxygen sensor, the fuel gas supply amount is corrected in real time, and the target air-fuel ratio is ensured;

(3) integrating gas supply closed-loop control, an ignition system, throttle control and a post-processing control system;

(4) the functions of starting, running, speed regulation, protection, fault treatment, stopping and the like of the engine CAN be controlled through the CAN bus;

(5) the equivalent ratio and the lean combustion can be controlled;

(6) has wide fuel adaptability: LPG, LNG, CNG, biogas, coal bed gas, etc.;

(7) various types of applications: generator sets, ships, distributed energy, gas heat pumps, water pump sets, and the like;

(8) the method is suitable for the operation requirement of the gas heat pump multi-split air conditioner.

The above embodiments are only for illustrating the technical concept and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and implement the present invention accordingly, and not to limit the protection scope of the present invention accordingly. All equivalent changes or modifications made in accordance with the spirit of the present disclosure are intended to be covered by the scope of the present disclosure.