CN201269149Y

CN201269149Y - Air feed system of natural gas single-fuel engine

Info

Publication number: CN201269149Y
Application number: CNU2008200638012U
Authority: CN
Inventors: 万义军; 杨志勇; 张自力; 程辉; 刘延伟; 陈孟强
Original assignee: DONGFENG NANCHONG AUTOMOBILE Co Ltd
Current assignee: DONGFENG NANCHONG AUTOMOBILE Co Ltd
Priority date: 2008-06-12
Filing date: 2008-06-12
Publication date: 2009-07-08
Anticipated expiration: 2018-06-12

Abstract

The utility model discloses an air supply system of a natural gas single-fuel engine. The air supply system provides the engine with air and fuel gas; the air enters an exhaust gas turbocharger through an air filter; the pressurized air enters an intercooler from an air outlet; the intercooled air enters a mixer; the fuel gas is compressed natural gas; after being decompressed by a first-level decompressor, the high-pressure natural gas stored in a steel cylinder is connected to a disconnecting valve, a second-level decompressor, and a third-level decompressor and the like by pipelines; the last level forms a last-level decompressor, the gas outlet end of which is communicated with the gas inlet end of the gas mixer; the two gases are supplied to a combustion chamber of an engine cylinder after being fully mixed in the mixer; the turbocharged and intercooled air mainly enters the mixer (5), and is communicated with the last-level decompressor of the fuel gas by a balance pipe (14); and the system can automatically adjust the pressure difference between the fuel gas and air which participate in the mixing, and ensure that the pressure difference is in a constant value range, thus leading the fuel gas and air to be mixed according to the best proportion.

Description

The air supply system of gas as single fuel motor

Technical field

The utility model relates generally to a kind of explosive motor, particularly a kind of motor that uses fuelled with natural gas.

Background technique

Because fuel oil such as gasoline that explosive motor uses, prices such as diesel oil rise steadily, people transfer the research natural gas engine, so that utilize the natural gas resource of China better, once applied for a Chinese invention patent as our company, name is called " supercharging engine with gas as single fuel ", number of patent application is 2005100223208, a gas mixer is disclosed, utilize mixing arrangement to be the motor air feed, to replace traditional EFI formula plenum system, the patent that not only our company application of mixer apparatus is arranged, as Chinese invention patent, name is called " mixer for natural gas in use for engine ", application number 200510018722.0, and the application people is a DongFeng Automobile Co., Ltd; China's utility application, name is called " gas-fueled vehicles engine gas mixer ", and the application people is a Nanchong Machinery Factory, Sichuan Petroleum Administration.Above-mentioned patent provides gas mixer miscellaneous, total trend is, all utilize the explosive motor of fuelled with natural gas, an air supply system is arranged, described air supply system supply engine air and combustion gas, air passes through air filter, enter exhaust-gas turbocharger, enter intercooler from the air outlet after the supercharging, in air after cold enter mixer, described combustion gas is a compressed natural gas, the high-pressure natural gas that steel cylinder stores reduces pressure through the one-level decompressor, be connected to stop valve by the road, to the second depressurized device, to three grades of decompressors ..., afterbody forms last stage pressure reducers, the gas of last stage pressure reducers goes out end and communicates with an inlet end of described gas mixer, two kinds of gases fully mix the firing chamber of back supply engine cylinder in mixer, but such system can't regulate required mixed gas automatically according to the needs of engine operating condition, for addressing this problem, people have designed the Ecu system and have regulated the combustion gas that enters cylinder automatically, but such system can't guarantee that also mixed gas obtains the mixing of optimal proportion, motor can not all obtain best combustion gas and Air mixing ratio all the time, thereby obtain maximum exerting oneself, what all known mixer structures all will solve is how even two kinds of gases mixing are, but do not note the combustion gas that participates in mixing and the pressure changing of air, pressure is relevant with flow, the pressure difference that exist of two kinds of gas particularly, therefore, present system is defective.

The model utility content

The purpose of this utility model provides an engine air supply systems, described system can overcome the shortcoming of prior art, automatically regulate the combustion gas of participation mixing and the pressure reduction of air, guarantee that pressure reduction is in a steady state value scope, thereby combustion gas and air are mixed with optimal proportion, guarantee that motor obtains optimum condition.

For achieving the above object, scheme of the present utility model is: through turbosupercharging and in air after cold mainly enter mixer, also communicate with the last stage pressure reducers of combustion gas by a balance tube.

Further scheme comprises that the air inlet end with balance tube and gas mixer joins, and the other end of described pipe communicates with last stage pressure reducers.

Adopt such scheme, the air supply system of known technology is become one the self-regulating control system of feedback quantity, and this system can provide best combustion gas and Air mixing gas according to the operating mode needs of motor, thereby has realized the purpose of this utility model.

Below in conjunction with diagram and embodiment scheme of the present utility model is described in more detail.

Description of drawings

Fig. 1 is the flow chart of the air supply system of gas as single fuel motor;

Fig. 2 is the parts connection diagram of the air supply system of gas as single fuel motor;

Fig. 3 is the structural drawing of reponse system among Fig. 2.

Embodiment

In the system block diagram as shown in Figure 1, the steel cylinder high-pressure natural gas enters 2 → three grades of decompressors 3 of high pressure relief device 1 → second depressurized device by the road, up to last stage pressure reducers 4, last stage pressure reducers 4 enter mixer 5 between be connected to a steam supply valve 13, another route air enters waste gas charging turbine 6 → cool off → enter mixer 5 through intercooler 7, the outlet side of mixer 5 enters cylinder 8, this system is connected to two branch roads, article one, the ECu control system that belongs to known technology, ECu indicates with footnote 9, it is designed that another branch road is scheme of the present utility model, can directly link last stage pressure reducers 4 through branch road 10 from intercooler, dotting out this is a connection that it is contemplated that, concrete connection is to be connected to last stage pressure reducers 4 from mixer air inlet end through branch road 11, and this also is the concrete Placement of this programme.

In the erection drawing as Fig. 2, connect each parts with pipeline and constitute a complete engine air supply systems, block diagram is described visually.Air supply system comprises air and combustion gas, air is through filter, the waste gas charging turbine, after the intercooler cooling, enter mixer 5, gas supply system comprises from the steel cylinder high-pressure natural gas to high pressure relief device 1, the second depressurized device of present embodiment and three grades of decompressors are in a combination decompressor 12, decompressor more than three grades is not set, the combustion gas of coming out from combination decompressor 12 is serially connected with a steam supply valve 13 by the control of Ecu system to the pipeline the mixer 5, mixer 5 is linked in the outlet side of valve 13, mixer 5 links to each other with the cylinder of motor, supply with the mixed gas that mixes in proportion, this is the primary path of engine air supply systems, feedback branch by conceptual design is arranged, in theory this feedback branch so long as the air that comes out from intercooler can the branch sub-fraction directly receive on the last stage pressure reducers, as the branch road in the block diagram 10, but consider that from structure the design of this programme is to manage 14 to the last stage pressure reducers of combination decompressor 12 from feedback of outlet side connection of mixer.Described feedback is to also being balance tube.

The structure that has comprised combination decompressor 12 and mixer 5 in the system diagram of Fig. 3.Combination decompressor 12 is included in a flat box inner chamber and is divided into two chambers, form secondary chamber 15 and three grades of chambeies 16, passage 17 intercommunications are arranged between two chambers, its passage has 18 its unlatchings of control of one or three grades of chamber valves, secondary chamber has suction port 19, there is air outlet 20 in three grades of chambeies, suction port 19 has one secondary valve 21 its unlatching of control, one compensated cavity 22 is arranged at the top in three grades of chambeies, porose between compensated cavity 22 and the three grades of chambeies 16, be coated with three grades of diaphragms 23 of one deck on the hole, be fixed with one or three grades of pressure springs 24 on the diaphragm 23, compensated cavity 22 has mouthful 25 external balance tubes 14, i.e. a feedback pipe in the flow chart.

The switching of the valve of secondary chamber suction port 19 is controlled by a leverage, described leverage has a secondary diaphragm 26, push down diaphragm with spring 27 above the diaphragm, the diaphragm the other end is provided with fulcrum 28, and the lever end 29 that diaphragm device forms is movably hinged a secondary valve 21.

Movable door structure between described secondary chamber 15 and the three grades of chambeies 16 also is that a lever 30 drives valves 18, balance pivot 31 is arranged, lever rear end links to each other with three grades of chamber diaphragms 23, has hole 32 on the dividing plate of secondary chamber, so that the pressed gas of secondary chamber can act on the diaphragm 26.

In the structural drawing of mixer, comprise mixed gas outlet 33, fuel gas inlet 34 has the diaphragm 35 of one group of symmetry in the chamber, the top middle part of diaphragm 35 and a pressure spring 36 join, a cone 37 is fixed in the following intermediate portion of diaphragm, and the conical section of cone 37 cooperates with a pipe mouth of pipe of 38, manages 38 and communicates with fuel gas inlet 34, this structure is a symmetry, the other end at mixer is a mixer suction port 39, is provided with an interface 40 on tube wall, connects balance tube 14.

For further specifying the working principle of this programme, decompressor among the above-mentioned figure and mixer are coupled together with balance tube 14, as shown in Figure 3, combination decompressor in the diagram is that second depressurized device and three grades of decompressors are combined, three grades of decompressors also are last stage pressure reducers, when the pressure rock gas that comes out from high pressure relief device 1 when second depressurized device suction port 19 enters, pressure has been reduced to about 1Mpa, when the gas pressure in the secondary chamber 15 during less than 27Kpa, 32 introductions act on the secondary diaphragm to gas from the hole, secondary diaphragm 26 below gas pressures can not overcome two-level spring 27 effects, secondary valve 21 can not be moved down seal gas inlet 19, so the pressure rock gas of 1Mpa enters in the secondary chamber 15, when the pressure in the secondary chamber 15 during greater than 27Kpa, secondary diaphragm 26 below gases can overcome two-level spring 27 effects greater than top pressure, secondary valve 21 is moved down seal inlet 19, throttle down, make gas can not enter secondary chamber 15, the pressure that has entered is that the combustion gas of 1Mpa is at the indoor dilution pressure of secondary chamber, until about 27Kpa, so the gas pressure of secondary chamber 15 maintains about 27Kpa all the time, rock gas enters three grades of chambeies 16 through secondary outlet 17 again, three grades of diaphragm 23 tops are subjected to the spring force effect and the action of air pressure that transports from import 25 by the balance tube 14 that is connected mixed gas inlet of three grades of pressure springs 24, when three grades of diaphragms of the natural pressure force rate in three grades of chambeies, 23 top pressure during greater than 4-5 foot water column, just can overcome the spring force of three grades of springs 24, allow three grades of diaphragms 23 upwards act on, under lever 30 effects, close three grades of air inlet passages 17, thereby make 4-5 feet water columns of air pressure difference maintenance behind the charge inter cooling that rock gas gas pressure and mixer in three grades of chambeies 16 advance, need to prove, three grades of chambeies 16 in fact also comprise one section cavity that one section steam supply valve 13 links to each other with mixing decompressor 12 by pipeline, so the adjustment of the pressure in three grades of chambeies 16 and steam supply valve 13 also has relation, described steam supply valve 13 is controlled by Ecu, the outlet side of steam supply valve 13 links to each other with the inlet end 34 of mixer 5, send into cylinder combustion through air and combustion gas that mixer 5 mixes in proportion through mixer air outlet 33, form negative pressure in the gaseous combustion rear cylinder, make diaphragm 35 tops be subjected to downward active force, when the pressure difference of the mixer air-inlet cavity 34 of the pressure of diaphragm 35 tops and below can overcome 36 effects of mixer spring, pressure spring makes progress, cone 37 is upwards moved, the mouth of pipe of pipe 38 is opened, combustion gas is flowed out from import 34 and is entered in the mixer chamber and air mixing, because the air pressure difference that mixes behind three grades of chamber rock gas gas of decompressor and the charge inter cooling that mixer advances is constant, present embodiment is through test, best pressure reduction is 4-5 foot water column, gaseous-pressure is higher than air pressure, so in the mixer air quantity and amount of natural gas than with mixed process in the cross-section area equal proportion passed through, thereby the air quantity of making and amount of natural gas are mixed into cylinder with desired proportions, after lighting the acting burning, pass through outlet pipe, enter pressurized machine and promote turbine, discharge from exhaust elbow.

The contribution of the technical program is and will have increased a feedback branch on the known air supply system, it is the branch road that balance tube 14 forms, such purpose is to provide one to obtain best rock gas and air Mixture according to operating mode to motor, the power that motor produces is relevant with rock gas that is advanced and air mass flow, pressure is for dependable flow, from the system diagram of Fig. 1 as can be known, there are two feedback branches in fact, article one, be the Ecu system of known technology, article one, be the set balance tube of the technical program 14 formed feedback branches, Ecu system control rock gas control valve 13, during each operating mode the optimum state of Ecu system acquisition motor, manifold absolute pressure sensor, intake air temperature sensor, each parameter such as engine water temperature sensor is set up database, during engine operation, again according to manifold absolute pressure sensor, intake air temperature sensor, the data of engine water temperature sensor, search the only control valve parameter under this operating mode, again by lambda sensor to this rock gas control valve parameter correction, last rock gas control valve changes the air feed cross-section area, to change to the flow of combustion gas in the mixer, but lambda sensor is arranged on the engine exhaust pipe, content by detecting tail gas is as the parameter correction, this has been a kind of detection afterwards, a kind of hysteresis is arranged, usually the fine adjustment of Ecu system as air supply system, the adjustment of the formed feedback branch of this programme is as initial adjustment, the function of Ecu system is done to replenish and improve, further improve the air supply system of gas as single fuel motor.

This programme balance tube 14 formed feedback branches are done as following analysis, by among Fig. 3 as can be known, the top that balance tube 14 inserts 22, the three grades of diaphragms 23 of compensated cavity in the combination decompressors 12 is subjected to the effect of two kinds of power altogether, the one, the air after the pressurization that enters from balance tube 14, establishing its pressure is P _Air, the 2nd, pressure spring 24 gives the spring force of three grades of diaphragms 23, uses P _SpringExpression, P _Spring=λ S, wherein λ is an elasticity coefficient, and S is a stroke, and the below of three grades of diaphragms 23 is subjected to the effect of gaseous-pressure, and establishing its power that acts on diaphragm is P _{Combustion gas}, have only the P of working as _{Combustion gas}P _Spring+ P _Air, three grades of valves 18 are promptly closed, i.e. P _{Combustion gas}-P _AirP _Spring, as long as promptly the pressure reduction between combustion gas and air during greater than acting force of the spring, three grades of valves 18 are promptly closed, and spring pressure P _SpringBe a pre-designed power, the spring force of this programme design is that pressure reduction that three grades of diaphragms 23 are subjected to upper and lower surface just can pressure spring 24 when being 4-5 foot water column makes on it and moves, thereby close three grades of valves 18, so the spring according to the above-mentioned parameter design can guarantee that the pressure reduction between rock gas and air is 4-5 foot water column, what this programme was emphasized always is, through overtesting, this pressure difference is the optimal proportion that forms mixed gas, meets the combustion condition of cylinder most.The air pressure that native system is sent here from balance tube 14 feedbacks is equivalent to set up one and rock gas comparative standard, and this technological scheme and Ecu are not to adjust relatively afterwards, but engine operating condition is adjusted immediately, and this hybrid mode improved reliability, mix more abundant, so its more remarkable effect, according to measuring and calculating, this device and similar type, as the device ratio that only uses Ecu to adjust as system, power improves, cost reduces, and is a kind of successful design scheme.

Claims

1, a kind of air supply system of gas as single fuel motor, described air supply system supply engine air and combustion gas, air passes through air filter, enter exhaust-gas turbocharger, enter intercooler from the air outlet after the supercharging, in air after cold enter mixer, described combustion gas is a compressed natural gas, the high-pressure natural gas that steel cylinder stores reduces pressure through the one-level decompressor, be connected to stop valve by the road, to the second depressurized device, to three grades of decompressors, afterbody forms last stage pressure reducers, and the gas of last stage pressure reducers goes out end and communicates with an inlet end of described gas mixer, and two kinds of gases fully mix the firing chamber of back supply engine cylinder in mixer, it is characterized in that: through turbosupercharging and in air after cold mainly enter mixer (5), also communicate with the last stage pressure reducers of combustion gas by a balance tube (14).

2, the air supply system of gas as single fuel motor according to claim 1 is characterized in that: the air inlet end of balance tube (14) with gas mixer (5) joined, and the other end of described pipe communicates with last stage pressure reducers.

3, the air supply system of gas as single fuel motor according to claim 2 is characterized in that: the other end of balance tube (14) links to each other with the compensated cavity of last stage pressure reducers.

4, the air supply system of gas as single fuel motor according to claim 1, it is characterized in that: combination decompressor (12) is included in a flat box inner chamber and is divided into two chambers, form secondary chamber (15) and three grades of chambeies (16), passage (17) intercommunication is arranged between two chambers, its passage has one or three grades of chamber valves (18) to control its unlatching, secondary chamber has suction port (19), there is air outlet (20) in three grades of chambeies, suction port (19) has one secondary valve (21) to control its unlatching, one compensated cavity (22) is arranged at the top in three grades of chambeies, porose between compensated cavity and the three grades of chambeies (16), be coated with three grades of diaphragms of one deck (23) on the hole, be fixed with one or three grades of pressure springs (24) on the diaphragm (23), compensated cavity (22) has mouthful (a 25) external balance tube (14).

5, the air supply system of gas as single fuel motor according to claim 4, it is characterized in that: the switching of the valve of secondary chamber suction port (19) is controlled by a leverage, described leverage has a secondary diaphragm (26), push down diaphragm with spring (27) above the diaphragm, the diaphragm the other end is provided with fulcrum (28), and the lever end (29) that diaphragm device forms is movably hinged a secondary valve (21).

6, according to the air supply system of claim 4 or 5 described gas as single fuel motors, it is characterized in that: the movable door structure between described secondary chamber (15) and the three grades of chambeies (16) also is that a lever (30) drives a valve (18), balance pivot (31) is arranged, lever rear end links to each other with three grades of chamber diaphragms (23), has hole (32) on the dividing plate of secondary chamber.

7, the air supply system of gas as single fuel motor according to claim 1, it is characterized in that: described mixer comprises mixed gas outlet (33), fuel gas inlet (34), the diaphragm (35) that one group of symmetry is arranged in the chamber, the top middle part of diaphragm and a pressure spring (36) join, a cone (37) is fixed in the following intermediate portion of diaphragm, the conical section of cone cooperates with the mouth of pipe of a pipe (38), pipe communicates with fuel gas inlet, this structure is a symmetry, the other end at mixer is mixer suction port (39), is provided with an interface (40) on tube wall, connects balance tube (14).