LNG Liquefied natural gas Engine Inlet Temperature control system and controlling method
Technical field
The present invention relates to LNG Liquefied natural gas technical field of engines, particularly relate to a kind of LNG Liquefied natural gas Engine Inlet Temperature control system and controlling method.
Background technique
Along with developing rapidly of China's economy and increasing rapidly of vehicle population, China is faced with many baptisms in energy development, there is no carbon smoke exhaust in combustion of natural gas process, be a kind of clean substitute fuel, be more and more subject to the attention of national governments.
LNG Liquefied natural gas motor is compared with conventional compression natural gas engine has the plurality of advantages that discharge is lower, course continuation mileage is long, Security is good.Therefore, LNG Liquefied natural gas motor has good market prospects.
The rock gas supplying method of conventional lng motor is LNG Liquefied natural gas through vaporizer vaporization in gaseous state and after heating up, then is depressurized to after setting value through pressure governor and enters motor through closure, suction tude.Therefore in whole rock gas supply process, lack accurate temperature control loop joint.When engine cold starting or low operating mode because coolant temperature is low, vaporize insufficient, the natural gas temperature after vaporization is low, causes HC and CO of motor to discharge higher; Motor is when high-load operation, and because coolant temperature is higher, after vaporization, the temperature of rock gas is too high, causes motor volumetric efficiency to reduce, and power character declines, and NOx emission raises.
Summary of the invention
Object of the present invention is exactly to solve the problem, propose a kind of LNG Liquefied natural gas Engine Inlet Temperature control system and controlling method, when this system overcomes LNG Liquefied natural gas motor low operating mode, too low HC, CO discharge caused of intake temperature is too high, the defect that during high operating mode, the too high power character caused of intake temperature is poor, NOx emission is too high, improves power character and the Economy of system.
To achieve these goals, the present invention adopts following technological scheme:
A kind of LNG Liquefied natural gas Engine Inlet Temperature control system, comprise: ECU, temperature, pressure and flow transducer, controlled thermal exchanger, and one-level temperature electronic controlling device: by controlling the flow of engine coolant, regulate the temperature of gaseous natural gas after liquid natural gas vaporization device; Secondary temperature electronic controlling device: by controlling the flow of engine coolant, the temperature secondary of gaseous natural gas is adjusted.
Described temperature, pressure are connected with ECU with secondary temperature electronic controlling device respectively with flow transducer, one-level temperature electronic controlling device, and described controlled thermal exchanger is arranged between rock gas stable-pressure device and natural gas injector, with engine coolant and carries out heat exchange.
Described one-level temperature electronic controlling device is arranged on the cooling water pipeline between LNG Liquefied natural gas motor and liquified natural gas vaporizing unit.
Described secondary temperature electronic controlling device is arranged on the cooling water pipeline between LNG Liquefied natural gas motor and controlled thermal exchanger.
Described one-level temperature electronic controlling device and secondary temperature electronic controlling device are electronic flow control valve.
Described temperature, pressure and flow transducer measure the temperature of gaseous natural gas after liquified natural gas vaporizing unit, pressure and flow parameter respectively, and after controlled thermal exchanger the temperature of gaseous natural gas, pressure and flow parameter.
A kind of controlling method of LNG Liquefied natural gas Engine Inlet Temperature control system, ECU gathers the temperature of the rear gaseous natural gas of vaporization, and gather engine power, rotating speed, ambient temperature parameter, the supplemental characteristic collected is compared with engine calibration data, by controlling the aperture of one-level temperature electronic controlling device, increase or reduce to flow through the flow of liquified natural gas vaporizing unit cooling liquid, control the temperature of the rear gaseous natural gas of vaporization.
ECU gathers the temperature of gaseous natural gas after controlled thermal exchanger, and gathers engine power, rotating speed, ambient temperature parameter, according to the aperture of the data point reuse secondary temperature electronic controlling device of demarcating in MAP, and the temperature of gaseous natural gas after secondary adjustment vaporization.
The aperture controlling I and II temperature electronic controlling device when motor starting cold is all adjusted to maximum; The aperture of the temperature control I and II temperature electronic controlling device when engine thermal startup or high speed large load operation according to cooling liquid adjusts to suitable gear.
The aperture of described I and II temperature electronic controlling device is manually arranged or is automatically adjusted by ECU.
Liquid natural gas flows into natural gas vaporization device by the road, liquified natural gas is vaporizated into gaseous natural gas by the heat that natural gas vaporization device absorbs cooling liquid, and the coolant rate flowing through natural gas vaporization device is controlled by one-level temperature electronic controlling device, the temperature of control cooling liquid measured by temperature, pressure and flow transducer of its flow is determined after ECU computing.Gaseous natural gas temperature after vaporization is controlled in certain limit, through surge tank, high-pressure shut-off, gas filter, voltage stabilizer, flows to controlled thermal exchanger, and controlled thermal exchanger adjusts the temperature secondary of rock gas, the coolant rate flowing through controlled thermal exchanger is controlled by secondary temperature electronic controlling device, and the temperature of control cooling liquid measured by temperature, pressure, flow transducer of its flow is determined after ECU computing.
The invention has the beneficial effects as follows:
According to technological scheme of the present invention, adopt LNG Liquefied natural gas Engine Inlet Temperature control system, control the temperature after liquid natural gas vaporization, and by one, secondary temperature electronic controlling device fine adjustment enters the natural gas temperature of electrically controlled injector, make LNG Liquefied natural gas motor in whole operating range, all have suitable rock gas intake temperature, overcome prior art cold starting, the intake temperature too low HC caused during low operating mode, during CO discharge too high and high operating mode, the too high power character caused of intake temperature is poor, the defect that NOx emission is too high, reduce dusty gas discharge amount, improve power character and Economy.
Accompanying drawing explanation
Fig. 1 is natural gas engine gas supply system flow chart of the prior art;
Fig. 2 is LNG Liquefied natural gas Engine Inlet Temperature control system flow chart of the present invention;
Fig. 3 is LNG Liquefied natural gas Engine Inlet Temperature control system operating diagram of the present invention;
Fig. 4 is the logical flow chart of LNG Liquefied natural gas Engine Inlet Temperature controlling method of the present invention.
Wherein, 201.LNG steel cylinder, 202. vaporizers, 203. surge tanks, 204. high-pressure shut-off, 205. gas filters, 206. voltage stabilizers, 207. controlled thermal exchangers, 208. secondary temperature electronic controlling devices, 209. temperature, pressure, flow transducer, 210. electrically controlled injectors, 211. gasoline combustion/air mixers, 212. closure, 213.LNG motor, 214.ECU, 215. one-level temperature electronic controlling devices.
Embodiment:
Below in conjunction with accompanying drawing and embodiment, the present invention will be further described:
As shown in Figure 1, in conventional lng gas supply system, LNG steel cylinder 201 stores liquid natural gas, makes LNG motor 213 have certain course continuation mileage.The liquified natural gas of LNG steel cylinder 201 is vaporizated into gaseous natural gas by vaporizer 202, forms coolant circuit from LNG motor 213 to vaporizer 202 cooling liquid pipeline and vaporizer 202 to LNG motor 213 cooling liquid pipeline.Sent to vaporizer 202 by heating via cooling liquid pipeline to be vaporizated into the heat that gaseous natural gas provides required for liquified natural gas in engine side cooling liquid.
Cooling liquid turns back to engine side heat exchanger to be reheated further across pipeline after vaporizer 202.Gaseous natural gas after surge tank 203 has certain storage volumetric vaporization also keeps the pressure stability in pipeline, and high-pressure shut-off 204 is responsible for opening or closing the rock gas leading to LNG motor 213.Rock gas after vaporization is further through gas filter 205, voltage stabilizer 106, mechanical thermal exchanger, after enter electrically controlled injector 210, ECU214 controls the emitted dose of electrically controlled injector 210 according to the working order of motor, after the rock gas of electrically controlled injector 210 injection mixes with air in gasoline combustion/air mixer 211, work by combustion in LNG motor 213 is entered through closure 212, for vehicle provides power, the waste gas that LNG motor 213 burns enters in after-treatment system and is further processed, and enters in air.Mechanical thermal exchanger in system can carry out rough adjustment to the temperature of gaseous natural gas.
According to the LNG Liquefied natural gas gas supply system of the prior art, in whole rock gas supply process, lack accurate temperature control loop joint.When engine cold starting or low operating mode because coolant temperature is low, vaporize insufficient, the natural gas temperature after vaporization is low, causes HC and CO of motor to discharge higher; Motor is when high-load operation, and because coolant temperature is higher, after vaporization, the temperature of rock gas is too high, causes motor volumetric efficiency to reduce, and power character declines, and NOx emission raises.
As shown in Figure 2 and Figure 3, in LNG Liquefied natural gas Engine Inlet Temperature control system of the present invention, comprise: ECU214, temperature, pressure and flow transducer 209, controlled thermal exchanger 207 and one-level temperature electronic controlling device 215: by the flow of control LNG motor 213 cooling liquid, regulate the temperature of gaseous natural gas in vaporizer 202; Secondary temperature electronic controlling device 208: by the flow of control LNG motor 213 cooling liquid, adjusts the temperature secondary of gaseous natural gas.
Temperature, pressure are connected with ECU214 with secondary temperature electronic controlling device 208 respectively with flow transducer 209, one-level temperature electronic controlling device 215, and described controlled thermal exchanger 207 is arranged between rock gas stable-pressure device and rock gas electrically controlled injector 210, with LNG motor 213 cooling liquid and carries out heat exchange.
One-level temperature electronic controlling device 215 is arranged on the cooling water pipeline between LNG Liquefied natural gas motor 213 and liquified natural gas vaporizer 202.Secondary temperature electronic controlling device 208 is arranged on the cooling water pipeline between LNG Liquefied natural gas motor 213 and controlled thermal exchanger 207.One-level temperature electronic controlling device 215 and secondary temperature electronic controlling device 208 are electronic flow control valve.Temperature, pressure and flow transducer 209 measures the temperature of gaseous natural gas after vaporizer 202, pressure and flow parameter respectively, and after controlled thermal exchanger 207 temperature of gaseous natural gas, pressure and flow parameter.
The liquid natural gas that LNG steel cylinder 201 stores, flow into vaporizer 202 by the road, liquified natural gas is vaporizated into gaseous natural gas by the heat that vaporizer 202 absorbs cooling liquid, and the coolant rate flowing through vaporizer 202 is controlled by one-level temperature electronic controlling device 215, the temperature of control cooling liquid measured by temperature, pressure and flow transducer 209 of its flow is determined after ECU214 computing.Gaseous natural gas temperature after vaporization is controlled in certain limit, through surge tank 203, high-pressure shut-off 204, gas filter 205, voltage stabilizer 206, flows to controlled thermal exchanger 207, the temperature secondary adjustment of controlled thermal exchanger 207 pairs of rock gases, the coolant rate flowing through controlled thermal exchanger 207 is controlled by secondary temperature electronic controlling device 208, and the temperature of control cooling liquid measured by temperature, pressure, flow transducer 209 of its flow is determined after ECU214 computing.
After natural gas temperature adjusts to proper range, enter electrically controlled injector 210, ECU214 controls the emitted dose of electrically controlled injector 210 according to the working order of motor, after the rock gas of electrically controlled injector 210 injection mixes with air in gasoline combustion/air mixer 211, work by combustion in LNG motor 213 is entered through closure 212, for vehicle provides power, the waste gas that LNG motor 213 burns enters in after-treatment system and is further processed, and enters in air.
Liquified natural gas vaporizing unit vaporizer 202, be coupled with engine-cooling system by one-level temperature electronic controlling device 215, and controlled cooling model liquid flows to the flow of vaporizer 202, to control the speed that vaporizer 202 absorbs heat, thus reach, control the object that liquefied natural gas vaporization is temperature after gaseous natural gas, the aperture of one-level temperature electronic controlling device 215 is determined according to the temperature computation of rock gas after vaporization by ECU214.
Secondary temperature control system, again adjusts the temperature of rock gas at gaseous natural gas after voltage stabilizer 206 flows into controlled thermal exchanger 207, and the natural gas temperature entering electrically controlled injector 210 is remained in ideal range.The adjustment of controlled thermal exchanger 207 pairs of gaseous natural gas temperature utilizes temperature, pressure, flow transducer 209 to gather the temperature of rock gas by ECU214, and then the aperture that controls secondary temperature electronic controlling device 208 is determined.
Present invention also offers a kind of method for operating this LNG Liquefied natural gas Engine Inlet Temperature control system, as shown in Figure 4.
Step S301, if motor is cold starting, now the temperature of engine coolant is low, adjusts to maximum, for the vaporization of LNG Liquefied natural gas and the adjustment of gas natural gas temperature provide enough heats by the gear controlling one-level electronic flow control valve and secondary electrons flow control valve.If motor is hot exposure, the gear controlling one-level electronic flow control valve and secondary electrons flow control valve is adjusted to suitable gear by the temperature according to cooling liquid.
Step S302, the automatic adjustment of liquid natural gas gaseous natural gas temperature after vaporizer 202 is vaporized.
After engine start, electric control system ECU 214 gathers the temperature of the rear gaseous natural gas of vaporization, and gather engine power, rotating speed, ambient temperature, the data gathered and engine calibration data compare, the aperture of adjustment one-level electronic flow control valve, increase or reduce to flow through the coolant rate of vaporizer 202, temperature natural after controlling vaporization.
Step S303, before electrically controlled injector 210, the secondary of gaseous natural gas temperature adjusts automatically.
Temperature, pressure, flow transducer 209 gather the parameters such as the natural gas temperature before electrically controlled injector, and electric control system ECU 214 is transferred to together with other Operational Limits and enviromental parameter, automatical control system adjusts the flow of secondary electrons flow control valve automatically according to the data of demarcating in MAP, and the temperature of rock gas is adjusted to ideal range.
In addition, the gear of one-level electronic flow control valve and secondary electrons flow control valve manually can be set according to different amblent air temperatures to improve control accuracy, also automatically can to adjust gear by electric control system ECU 214 according to runnability.
By reference to the accompanying drawings the specific embodiment of the present invention is described although above-mentioned; but not limiting the scope of the invention; one of ordinary skill in the art should be understood that; on the basis of technological scheme of the present invention, those skilled in the art do not need to pay various amendment or distortion that creative work can make still within protection scope of the present invention.