RU2520787C1 - Gas engine control system - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: control system can be used for control over gas engine incorporated with motor generator and co-generators for application of gas or mix of gases of various calorific capacity. Proposed system comprises electronic control unit and thermocouple connected therewith and arranged in exhaust manifold, crankshaft rpm, detonation and air flow rate transducers, camshaft angular position transducers and gas pressure and temperature transducers. Additionally, this system comprises bypass solenoid valve arranged at two-stage low-pressure reducer first stage connected on one side via said bypass solenoid valve with said first stage and, on the other side, via three-way control valve with gas main line. Relative calorific capacity of gas is defined by off-gas temperature and working gas pressure corrected to use the increased gas pressure from first stage for operation of gas engine at increased gas feed.

EFFECT: higher control efficiency.

1 dwg

Description

The invention relates to engine building, and in particular to a control system for a multi-fuel gas piston engine, and is intended to be used in the field of energy supply as a part of motor generators and cogeneration plants.

The operation of power plants based on gas piston engines has shown the urgency of the problem of using a gas or a mixture of combustible gases of different calorific value, including low.

A known gas piston engine control system (RU 2424440 C1; IPC F02D 19/02, F02M 21/02; publ. 07/20/2011), comprising a housing in which a crankshaft with a flywheel is installed, working cylinders with intake and exhaust manifolds connected to them, consisting of a low pressure pipe connected to a booster compressor, to which a high pressure pipe is connected, branched in front of the intake manifold by the number of working cylinders. Branches of the high pressure pipeline are connected through the inlet pipes to the inlet manifold and in each of them two gas flow control valves are installed, one of which is installed in the additional supply channel. The control of the gas piston engine speed is organized based on feedback through the crankshaft speed sensor. If the amount of incoming gas is insufficient for maintaining the required load-speed mode of the gas piston engine due to insufficient calorific value of the gas, then the closed-loop control circuit consisting of the crankshaft speed sensor and all gas flow control valves adjusts the composition of the gas-air mixture for Booster compressor performance control account.

The disadvantage of the presented gas piston engine control system is the excessive complexity of the design of the fuel supply system due to the use of: a booster compressor; high pressure pipelines with branches for each working cylinder and a large number of gas flow control valves.

Known gas engine control system (RU 2434150 C2; IPC F02B 43/00, F02M 21/02, F02M 21/04; publ. 11/20/2011), comprising a housing in which a crankshaft with a flywheel is installed, working cylinders are connected to them inlet and exhaust manifolds, consisting of a low pressure pipe connected to a booster compressor, to which a high pressure pipe is connected, branched in front of the intake manifold according to the number of working cylinders. In each branch of the high pressure pipeline connected to the intake manifold, one gas flow control valve is installed. An additional supply channel is connected to the low pressure pipeline to the booster compressor, equipped with a gas flow sensor and an additional gas flow control valve. In addition, the system is equipped with an air cooler and a gas-air mixer. For feedback on the speed of the crankshaft, a speed sensor is used. The required amount of incoming gas is carried out by regulating the performance of the booster compressor.

The disadvantage of the presented gas piston engine control system is the excessive complexity of the design of the fuel and air supply systems due to the use of: a booster compressor; high pressure pipelines with branches for each working cylinder, on which gas flow control valves are installed; an additional inlet channel equipped with an additional flow control valve, and a gas-air mixer.

A known gas piston engine control system (EP 0142490 A2; IPC F02D 19/02, F02B 43/00, F02D 35/00; publ. 05/22/1985), which uses a subsystem to directly determine the calorific value of a gas by analyzing its chemical composition. According to the level of methane content in the gas, a signal is generated using a special sensor to adjust the gas pressure, and therefore its quantity. At low calorific value of gas, its pressure rises by means of a booster compressor, and feedback is used to regulate the amount of air entering the intake manifold using a thermocouple and an oxygen sensor installed in the exhaust manifold.

However, the use of a system for directly determining the calorific value of gas, a booster compressor and an oxygen sensor complicates the system and increases its cost.

Known electronic control system for the fuel supply of a gas piston engine with a phased distributed gas injection (Zolotnitsky VA Automotive gas fuel systems. - M .: Astrel, 2009. - 128 p., Ill.). The gas-piston engine contains a housing in which a crankshaft with a flywheel is installed, working cylinders with intake and exhaust manifolds connected to them. This system consists of at least a two-stage low pressure reducer, the last stage of which is connected through a low-pressure pipeline to a gas line equipped with pressure sensors, gas temperature and gas electromagnetic nozzles, each of which is connected through a hose equipped with a fitting with an intake manifold in the immediate vicinity of working cylinders containing high-voltage ignition modules and connected to the exhaust manifold, at the outlet of which an oxygen sensor is installed . The system also includes a crankshaft sensor located in the body of the gas engine in the immediate vicinity of the flywheel.

The disadvantage of this fuel supply system for a gas piston engine with a phased distributed gas injection is the inability to use gas of different calorific value, including low, as well as the presence of an expensive oxygen sensor.

For the present invention, the closest of the analogues in technical essence, selected as a prototype of a gas piston engine control system, is a gas piston engine control system (RU 106662 U1; IPC F02B 63/04; F02D 19/02; F02P 3/00; publ. 20.07. 2011), comprising a housing in which a crankshaft with a flywheel, a camshaft, working cylinders with intake and exhaust manifolds connected to them, as well as an air supply line connected to the intake manifold are installed. The control system consists of at least a two-stage low pressure reducer, the last stage of which is connected via a low pressure pipeline to a gas line equipped with gas electromagnetic nozzles, the lower part of each of which is located in the intake manifold in the immediate vicinity of the working cylinders containing high-voltage ignition modules and connected to the exhaust manifold, in which there is one thermocouple for each working cylinder, respectively, and at the outlet The oxygen sensor has been updated. The system also includes an electronic control unit, electrically connected to the sensors of the crankshaft speed, camshaft angle and detonation, located in the housing in the immediate vicinity of the flywheel, camshaft and working cylinders, respectively, an electrically controlled throttle and an air flow sensor installed in the air supply line, gas electromagnetic nozzles, high-voltage ignition modules, as well as thermocouples and oxygen sensors om installed in the exhaust manifold.

This gas piston engine control system also has a drawback: the inability to use gas of different calorific value, including low.

The objective of the invention is to provide a control system for a gas piston engine with the possibility of using gas or a mixture of combustible gases of different calorific value, including low. At the same time, the gas used in the gas engine can be of natural, oil, or biological origin.

A gas piston engine control system comprising a housing in which a crankshaft with a flywheel, a camshaft, working cylinders with intake and exhaust manifolds connected to them, as well as an air supply line connected to the intake manifold, consisting of at least a two-stage low pressure reducer, are installed, the last stage of which is connected by means of a low pressure pipeline to a gas line equipped with gas electromagnetic nozzles, the lower part of each of which s located in the intake manifold in the immediate vicinity of the working cylinders containing high-voltage ignition modules and connected to the exhaust manifold, in which at least one thermocouple is located, and from an electronic control unit electrically connected to the sensors of the crankshaft speed, the angular position of the camshaft and detonation, located in the housing in close proximity to the flywheel, camshaft and working cylinders, respectively, electrically controlled throttle hydrochloric damper and the air flow sensor installed in the air supply lines, gas solenoid injectors, ignition modules, high voltage and thermocouple. The gas engine control system is also equipped with a bypass solenoid valve installed in the first stage of at least a two-stage low pressure reducer, an overpressure pipe connected on one side via an bypass solenoid valve with the first stage of at least a two-stage low pressure reducer, and on the other hand through three-way control valve with a gas line, additionally equipped with pressure and gas temperature sensors, and starting solenoid valve, three-way control valve, gas pressure and temperature sensors are electrically connected to the electronic control unit.

The application of this system is based on the peculiarity of a gas piston engine that a change in the calorific value of a gas can be judged approximately by a change in the temperature of the exhaust gases, and since it is not required to accurately determine the calorific value of a gas, the gas piston engine control system can take this feature into account. This is the novelty of the invention. So, the dependence of the temperature of the exhaust gases on the calorific value of the gas can be judged on the basis of the formula:

$${\text{H}}_{\text{u}}={\text{c}}_{\text{v}}\cdot \text{(T}-{\text{T}}_{\text{0}}\text{)}\text{,}\text{(one)}$$

where H _u is the calorific value of the gas, kJ / m ³ ;

C _y is the volumetric heat capacity of the substances in the exhaust gas, kJ / (m ³ · K);

T is the temperature of the exhaust gas, K;

T ₀ - gas temperature in the gas line, K.

The database of the electronic control unit contains the parameters of the gas adopted as the standard. As a result, formula (1) will take a special case, having the form:

$${\text{H}}_{\text{u1}}={\text{c}}_{\text{v1}}\cdot {\text{(T}}_{\text{one}}-{\text{T}}_{\text{0}}\text{)}\text{,}\text{(2)}$$

where H _u1 is the reference calorific value of the gas, kJ / m ³ ;

c _v1 - reference volumetric heat capacity of substances in the composition of the exhaust gases, kJ / (m ³ · K);

T ₁ - reference temperature of the exhaust gases, K.

In addition to the gas adopted as the standard, a gas or a mixture of combustible gases, the calorific value of which is unknown, can be used to maintain the gas piston engine at a given load-speed mode. Therefore, the actual calorific value of the gas can be represented by a special case of formula (I):

$${\text{H}}_{\text{u2}}={\text{c}}_{\text{v2}}\cdot {\text{(T}}_{\text{2}}-{\text{T}}_{\text{0}}\text{)}\text{,}\text{(3)}$$

where c _v2 is the actual volumetric heat capacity of the substances in the exhaust gas, kJ / (m ³ · K);

T ₂ is the actual temperature of the exhaust gas, K.

By formula (3), it is not possible to determine the actual calorific value of gas, since a sufficient amount of information is not received in the electronic control unit, or rather, the actual volumetric heat capacity of the substances in the exhaust gas is not known. Therefore, in accordance with the invention of a gas piston engine control system, it is proposed to determine the relative calorific value of the gas, which implies the calculation of the actual calorific value of the gas relative to the reference value, as a result, formula (1) is converted:

$${\text{H}}_{\text{u1-2}}={\text{c}}_{\text{v1}}\cdot {\text{(T}}_{\text{one}}-{\text{T}}_{\text{2}}\text{)}\text{,}\text{(four)}$$

In accordance with the value of the relative calorific value of gas calculated by formula (4), the electronic control unit adjusts the gas and air supply, the moment of operation of the high-voltage ignition modules, and also the operating value of the gas pressure according to the algorithm laid down in it. The proposed gas piston engine control system allows gas to be supplied through a gas supply line and at least a two-stage low pressure reducer, when the last stage reaches the working value of gas pressure, into a low pressure pipeline through which gas enters the intake manifold and is dosed there using gas nozzles, where it is mixed with the air entering through the air supply line and dosed there by the throttle, moreover, the dosing accuracy of both components of the air-fuel mixture is carried out using an electronic control unit based on an analysis of the readings of the sensors for the crankshaft speed, the angular position of the camshaft, detonation and air flow; Further, the gas-air mixture is sucked into the working cylinders, ignited by the command of the electronic control unit from the high-voltage ignition modules, and burns out, doing useful work. The exhaust gases formed after combustion of the gas-air mixture are forced into the exhaust manifold, where their temperature is measured using a thermocouple and its value is transmitted to the electronic control unit by means of which the obtained actual temperature of the exhaust gases is compared with the reference temperature stored previously in the memory of the electronic control unit exhaust gas, which is used to calculate the relative calorific value gas quality, and, as a result, adjustment of the working value of the gas pressure, after which a control signal is supplied from the electronic control unit to the bypass solenoid valve, through which the high-pressure gas is removed from the first stage of at least a two-stage low-pressure reducer to the high-pressure pipeline, and then it is fed through a three-way control valve, open at the command of the electronic control unit, into the gas line.

Significant differences of the proposed gas piston engine control system from the selected prototype are that the first stage of at least a two-stage low pressure reducer is additionally equipped with a bypass solenoid valve connected to the high pressure pipe, which is connected to the gas line through a three-way control valve, and the gas line equipped with pressure and gas temperature sensors.

In FIG. shows a diagram of a gas engine control system. The control system for a gas piston engine 1, consisting of a housing in which a crankshaft with a flywheel, a camshaft, working cylinders 2 with inlet 3 and exhaust 4 collectors connected to them, comprising an air supply line 5 connected to the intake manifold 3 and a gas supply line 6 s are installed a two-stage low pressure reducer 7 installed in it, having two stages (the first - 7a and the second - 7b, respectively), the second stage 76 of which is connected via a low-pressure pipeline 8 through three the bottom control valve 9 with a gas line 10, and the first stage 7a is connected via an overflow solenoid valve 11 to the overpressure pipe 12, which in turn is connected via a three-way control valve 9 to the gas line 10, equipped with pressure sensors 13 and gas temperature 14, and also gas electromagnetic nozzles 15, the lower part of each of which is placed in the intake manifold 3 in the immediate vicinity of the working cylinders 2 containing high-voltage ignition modules 16 and data with the exhaust manifold 4, in which the thermocouple 17 is located. In addition, the gas piston engine control system includes an electronic control unit 18, electrically connected to the sensors of the rotational speed of the crankshaft 19, the angular position of the camshaft 20 and detonation 21 located in the housing in close proximity from the flywheel, camshaft and working cylinders 2, respectively, by an electrically controlled throttle valve 22 and an air flow sensor 23 installed in the air supply line 5, gas Vym electromagnetic injector 15, the high voltage ignition module 16, thermocouple 17, bypass solenoid valve 11, three-way regulating valve 9, the pressure sensor 13 and the temperature of gas 14.

The gas piston engine control system operates as follows (see. Fig.).

Gas is supplied through a gas supply line 6 to a two-stage low pressure reducer 7, in the second stage 76 of which the gas pressure is reduced to the operating value set by the electronic control unit 18, after which gas is supplied from the second stage 76 of a two-stage low pressure reducer 7 to the low pressure pipeline 8, by which, having passed through a three-way control valve 9, it enters the gas line 10. By means of gas pressure sensors 13 and gas temperature 14, which are electrically connected to the electronic control unit 18, Monitoring of the operating pressure and gas temperature, respectively, is initiated. From the gas line 10, with the help of gas electromagnetic nozzles 15, gas is supplied to the intake manifold 3, and air enters through the air supply line 5, the amount of which is regulated by an electrically controlled throttle valve 22 based on measurements using an air flow sensor 23, electrically connected to the electronic control unit 18. In the intake manifold 3, gas and air are mixed, forming a gas-air mixture, sucked into the working cylinders 2, ignited under the influence of high-voltage modes it plugs 16 and perform useful work. As a result, the exhaust gases are formed, which are forced into the exhaust manifold 4, in which the temperature of the exhaust gases is measured by means of a thermocouple 17 in order to prevent overheating of the working cylinders 2. Distributed dosing of gas through the working cylinders 2 is carried out through gas electromagnetic nozzles 15, air is supplied to the intake manifold 3 - through the electrically controlled throttle valve 22, the ignition of the gas-air mixture in the working cylinders 2 - high-voltage ignition modules 16, on command from the electric of the control unit 18, and developed on the basis of an analysis of the state of the gas piston engine 1, carried out by constantly interrogating the sensors of the rotational speed of the crankshaft 19, the angular position of the camshaft 20, detonation 21, pressure 13 and gas temperature 14, air flow 23 and thermocouple 17. In addition in addition, according to the testimony of the sensors of the rotational speed of the crankshaft 19, detonation 21, and thermocouple 17, the emergency state of the gas piston engine 1 is predicted, and the command and gas and air up to complete termination.

If the amount of incoming gas is not enough to maintain the required load-speed regime of the gas piston engine 1, due to the low calorific value of the gas, in other words, at the modes near the external speed characteristic and the cold start modes, the working pressure of the gas pressure is adjusted and a new value is set and then a control signal is supplied to the bypass solenoid, additionally installed in the first stage 7a of the two-stage low-pressure reducer 7 at the valve 11. With its help, the high-pressure gas is discharged from the first stage 7a of the two-stage low pressure reducer 7 to the high-pressure pipe 12, then through the three-way control valve 9 to the gas line 10, where the operating value is monitored by pressure sensors 13 and gas temperature 14 the pressure and temperature of the high pressure gas, respectively, and from there the high pressure gas is supplied through the gas electromagnetic nozzles 15 to the intake manifold 3. Thus, through the gas electromagnetic nozzles 15 into the intake manifold 3, an already changed amount of high pressure gas is supplied, air is sucked in through the air supply line 5, the amount of which is regulated by turning the electrically controlled throttle valve 22. In the intake manifold 3, the high-pressure gas and air are mixed, forming a high-pressure gas-air mixture, sucked into the working cylinders 2 and flammable under the influence of high-voltage ignition modules 1 6 according to the adjusted value of the moment of their srab melting.

With the help of this gas piston engine control system, the gas piston engine can be efficiently operated in modes near the external high-speed characteristic when using gas or a mixture of combustible gases of different calorific value and the cold start of the gas piston engine is improved, since the system design allows controlling not only the composition of the gas-air mixture and torque triggering of high-voltage ignition modules, but also the operating value of the gas pressure. A positive effect from the introduction of the proposed system and method for controlling a gas piston engine should also be expected in reducing the cost of controlling a gas piston engine without the use of a booster compressor, an oxygen sensor and a system for directly determining the calorific value of gas.

Claims (1)

A gas piston engine control system comprising a housing in which a crankshaft with a flywheel, a camshaft, working cylinders with intake and exhaust manifolds connected to them, as well as an air supply line connected to the intake manifold, consisting of at least a two-stage low pressure reducer, are installed, the last stage of which is connected by means of a low pressure pipeline to a gas line equipped with gas electromagnetic nozzles, the lower part of each of which s located in the intake manifold in the immediate vicinity of the working cylinders containing high-voltage ignition modules and connected to the exhaust manifold, in which at least one thermocouple is located, and from an electronic control unit electrically connected to the sensors of the crankshaft speed, the angular position of the camshaft and detonation, located in the housing in close proximity to the flywheel, camshaft and working cylinders, respectively, electrically controlled throttle a damper and an air flow sensor installed in the air supply line, gas electromagnetic nozzles, high-voltage ignition modules and a thermocouple, characterized in that the system is additionally equipped with a bypass solenoid valve installed in the first stage of at least a two-stage low pressure reducer, an overpressure pipe connected on the one hand, through a bypass solenoid valve with a first stage of at least a two-stage low gearbox phenomenon, and on the other side via a three-way control valve with the gas manifold is further equipped with pressure sensors and the temperature of the gas, the bypass solenoid valve, three-way regulating valve, pressure and gas temperature sensors are electrically connected to the electronic control unit.

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