CN202330026U - Steady flow test bed for measuring performance of engine intake systems - Google Patents

Abstract

The utility model discloses a steady flow test bed for measuring the performance of engine intake systems. The test bed comprises a cylinder cover-positioning system, a simulative air cylinder, a vortex exhaust pipe, a tumble exhaust pipe, a vane anemometer, a tachometer, a pressure meter, a flowmeter, an exhaust duct, a pressure-stabilizing box and other parts. The test bed can simultaneously measure the macroscopical large-scale vortex and tumble motion intensity generated by an engine intake system and the flow coefficient, and can be used in the process of developing novel air inlets, inlet valves and combustion chambers for engines and for detecting the performance of intake systems in the process of engine manufacturing.

Description

Measure performance steady flow testbed of engine aspirating system

Technical field

The present invention relates to engine and make the field, specifically is the steady flow testbed of a kind of performance of measuring engine aspirating system.Can in the performance history of the novel air intake duct of engine, inlet valve, firing chamber, use, be used to measure the eddy flow ability and the charging efficiency of gas handling system.Also can be used for detecting in the engine manufacture process performance of gas handling system.

Background technology

The characteristic of the gas handling system of engine has decisive influence to the performance of engine.Its reason is that gas handling system can organize intake process, causes air-flow in the cylinder according to certain mode motion, causes the combustion process of improving engine, comprises and improves burning rate, rate of heat release.The charging efficiency of gas handling system can directly influence the output power of engine simultaneously.The factor of the gas handling system characteristic of decision engine comprises the geometric configuration of air intake duct, firing chamber and the characteristics of motion of inlet valve etc.

As everyone knows, the gas handling system of engine all must make air inlet in cylinder, produce to rotatablely move.Two kinds of basic patterns that rotatablely move are arranged, eddy current (swirl) and roll stream (tumble).Fig. 1 is an eddy current and the synoptic diagram that rolls the stream motor pattern in the cylinder.These two kinds of air motion patterns are different to the influence mechanism of the combustion process of engine.Eddy motion is meant the motion of rotation flow motion around cylinder-bore axis.The intake process piston moves down, move on the compression process piston, and the motion of air-flow and cylinder wall surface generation shearing force cause turbulent flow constantly to produce in the cylinder, have accelerated flame propagation velocity.And roll stream being meant rotatablely move around with the motion of the perpendicular axis of cylinder-bore axis.Stream is rolled in formation in the intake process later stage, and along with piston rises, cylinder space diminishes in the compression process, until rolling the stream motion fragmentation takes place, and forming with the large scale whirlpool is master's field of turbulent flow, has further accelerated flame propagation velocity.Theoretical and experiment shows that eddy current and the hybrid motion pattern of rolling stream claim that again inclined-axis swirl is the most remarkable to the improvement of engine combustion process.Organizing intake process to produce the air inlet rotation mainly is to be accomplished by the geometric configuration of air intake duct and firing chamber.

The eddy flow ability of the air-flow in the cylinder is with swirl ratio or roll stream and represent than r,

$r=\frac{{\mathrm{\ω}}_s}{{\mathrm{\ω}}_e}$

R is swirl ratio or rolls the stream ratio in the formula; ω _sBe rotational speed of eddy current or roll circulation speed; ω _eIt is engine speed.Engine intake process is transient state (in time change), and r measures on engine aspirating system steady flow testbed.

Another performance index of gas handling system are coefficient of flow of gas handling system.It is defined as the gas volume of entering cylinder and the ratio of displacement volume.Because airflow passes air intake duct, inlet valve, firing chamber in the intake process will inevitably run into resistance to flow, influence charging efficiency.The charging efficiency of engine reduces the output power that means engine and descends.

The intake process of engine is transient state (in time change), and the measurement of above-mentioned parameter (swirl ratio or roll stream than, coefficient of flow) is generally carried out under steady flow condition.Will be during measurement according to different inlet valve lift location fixing inlet valve one by one; The measurement of under each IO Intake Valve Opens position, carrying out rotational speed of eddy current or rolling circulation speed and charge flow rate; The measurement result that obtains under the quasi-steady condition is carried out integral operation, finally obtain the eddy flow ability and the charging efficiency index of this gas handling system.Such test-bed is called as the steady flow testbed of the performance of measuring engine aspirating system.The current stabilization experimental result to self of engine aspirating system relatively by meaning.Exist at present and measure eddy current or roll the experiment table of stream motion specially, but the eddy current in the cylinder with roll the stream motor pattern and have tangible differently, testing table should be measured the swirling motion of the interior two kinds of large scales of cylinder cylinder simultaneously.

In sum, be to measure the performance of engine aspirating system, need both eddy flow ability in the energy measurement cylinder, (comprise eddy current and roll stream), measure device charging efficiency, that have industrial applicibility of engine simultaneously.

Summary of the invention

The purpose of this invention is to provide the steady flow testbed of a kind of performance of measuring engine aspirating system, it can measure eddy current and the swirling motion that rolls two kinds of large scales of stream in the cylinder cylinder simultaneously, and the coefficient of flow of gas handling system.This testing table comprises cylinder cover positioning system, simulation cylinder, eddy current gas outlet, rolls parts such as stream gas outlet, blade anemoscope, tachometer gage, pressure gauge, flowmeter, exhaust duct, pressurizer tank.The annexation of each parts is: a cylinder cover positioning system; It connects a simulation cylinder down; What the simulation cylinder connected that an inside is equipped with that eddy current gas outlet and inside of a blade anemoscope is equipped with a blade anemoscope rolls the stream gas outlet, the eddy current gas outlet with roll the stream gas outlet and be connected to a pressurizer tank jointly, be connected to exhaust duct then; Exhaust duct connects pressure gauge and flowmeter, receives another pressurizer tank again.

The technical scheme that the present invention adopts:

Steady flow testbedly go up swirl ratio or roll stream than being defined as

$N_t\left(\mathrm{\θ}\right)=\frac{N_s\left(\mathrm{\θ}\right)V_h}{30Q_s\left(\mathrm{\θ}\right)},---\left(1\right)$

N in the formula _s(θ) be the rotating speed of a certain valve stroke lower blade anemoscope, dimension is rev/min; Q _s(θ) be volumetric flow of gas under a certain valve stroke, dimension is a rice ³/ second; θ is an engine crankshaft corner, can convert valve lift height to here; V _hIt is engine cylinder displacement.The coefficient of flow of gas handling system does

$C_f\left(\mathrm{\θ}\right)=\frac{Q_s\left(\mathrm{\θ}\right)}{{\mathrm{AV}}_0},---\left(2\right)$

V in the formula ₀Be theoretical intake velocity, Dimension is a meter per second; Δ p is the pressure reduction in the flowmeter; A is an inlet valve valve seating area.

The performance index of gas handling system need or be rolled the stream ratio to swirl ratio, coefficient of flow carries out integration, and obtain the average vortex ratio of intake process or roll the stream ratio, and average flow coefficient, as the index of weighing the gas handling system performance.Average vortex compares or rolls stream than being defined as

$R=\mathrm{\&pi;}{\&Integral;}_0^{\mathrm{\&pi;}}{N}_t\left(\mathrm{\&theta;}\right){(\frac{1}{2}\sin \mathrm{\&theta;}+\frac{\mathrm{\&lambda;}}{4}\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="HSA00000585314800021.png"\; state="\{\{state\}\}">sin</figure-callout>}2\mathrm{\&theta;})}^2\mathrm{d\&theta;}.---\left(3\right)$

Consider the influence of ratio of compression and charging efficiency, pass through the average vortex ratio of revising or roll stream than doing

$\stackrel{\&OverBar;}{R}=\frac{(\mathrm{\&epsiv;}-1)\mathrm{\&eta;}}{\mathrm{\&epsiv;}}R;---\left(4\right)$

Average flow coefficient does

${\stackrel{\&OverBar;}{C}}_f=\frac{1}{\mathrm{\&pi;}{\&Integral;}_0^{\mathrm{\&pi;}}{\left(\frac{1}{C_f\left(\mathrm{\&theta;}\right)}\right)}^2{(\frac{1}{2}\sin \mathrm{\&theta;}+\frac{\mathrm{\&lambda;}}{4}\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="HSA00000585314800021.png"\; state="\{\{state\}\}">sin</figure-callout>}2\mathrm{\&theta;})}^3\mathrm{d\&theta;}}.---\left(5\right)$

Fig. 2 is a steady flow testbed embodiment layout of measuring the performance of engine aspirating system.Shown in figure, for the eddy current of measuring large scale in the cylinder flows motion with rolling, must be placed on a vane type anemoscope in the eddy current gas outlet of simulation cylinder, measure eddy current and rotatablely move; Be placed on rolling in the stream gas outlet of traverse to another vane type anemoscope, measurement is rolled stream and is rotatablely moved.And in the actual moving process, eddy current and the position of rolling stream in the engine cylinder, power is all in continuous variation, so the rotating speed of anemoscope has only reflected the moving situation of most of air-flow in the ad-hoc location upper cylinder half.The result of current stabilization simulated experiment relatively is valuable as self.During test; Let the fan blower air draught; The pressure differential deltap P that regulates in the pressure gauge through variable valve is a certain value; Read flow and the blade anemoscope rotating speed in the tachometer gage in the flowmeter, can obtain swirl ratio or roll stream than

and coefficient of flow

Advantage of the present invention:

The steady flow testbed large scale eddy current that can measure the macroscopic view of engine aspirating system generation simultaneously of the performance of the measurement engine aspirating system that the present invention proposes flows exercise intensity and coefficient of flow with rolling.This apparatus structure is simple, easy and simple to handle, is easy to safeguard, can be used for novel air intake duct, the inlet valve of engine, the performance history of firing chamber, also can be used for detecting in the engine manufacture process performance of gas handling system.

Description of drawings

Fig. 1 (a) is an eddy motion pattern diagram in the cylinder; Fig. 1 (b) is an engine air in-cylinder tumble flow motor pattern synoptic diagram.Among the figure, 16 pistons, 17 cylinders, 18 exhaust valves, 19 inlet valves, 20 air intake ducts, 5 eddy motion directions, 7 are rolled stream direction of motion.

Fig. 2 is a steady flow testbed embodiment layout of measuring the performance of engine aspirating system.Among the figure, 1 pressurizer tank, 2 blade anemoscopes, 3 eddy current gas outlets, 4 tachometer gages, 5 eddy motion directions, 6 simulation cylinders, 7 roll stream direction of motion, 8 tachometer gages, 9 roll stream gas outlet, 10 blade anemoscopes, 11 pressure gauges, 12 flowmeters, 13 fan blowers, 14 pressurizer tanks, 15 exhaust ducts.

Fig. 3 is a steady flow testbed specific embodiments layout of measuring the performance of engine aspirating system.Among the figure, 19 inlet valves, 21 cylinder covers, 22 cylinder cover positioning systems, 6 simulation cylinders, 3 eddy current gas outlets, 4 tachometer gages, 23 quartz windows, 10 blade anemoscopes, 14 pressurizer tanks, 24 connecting tubes, 15 exhaust ducts, 11 pressure gauges, 12 flowmeters, 14 pressurizer tanks, 13 fan blowers, 10 blade anemoscopes, 23 quartz windows, 8 tachometer gages, 9 roll stream gas outlet, 21 air intake ducts.

Embodiment

Further specify the steady flow testbed structure and the principle of the performance of the measurement engine aspirating system that the present invention proposes with a specific embodiments.Fig. 3 is a steady flow testbed specific embodiments layout of measuring the performance of engine aspirating system.Shown in figure, at first on the simulation cylinder, settle the cylinder cover positioning system, purpose is for cylinder cover and simulation cylinder are aligned.For the eddy current of measuring large scale in the cylinder flows motion with rolling, must be placed on a vane type anemoscope in the eddy current gas outlet of simulation cylinder, measure eddy current and rotatablely move; Be disposed across rolling in the stream gas outlet of simulation cylinder to another vane type anemoscope, measurement is rolled stream and is rotatablely moved.Eddy current, roll stream gas outlet diameter for the simulation cylinder diameter 2/3rds.The eddy current gas outlet is in the simulation cylinder bottom; Roll the stream gas outlet and be installed in the bottom of simulating the cylinder-bore axis direction, purpose is that the stream that rolls that the simulation air inlet ends constantly moves.Eddy current drives its rotation with the blade anemoscope that rolls in the stream gas outlet by air-flow.Eddy current with roll stream and little quartz window arranged on the gas outlet, outside photoelectricity tacho aligns the above sensor of blade wind speed, with record blade anemoscope with rotating speed.

Eddy current with roll stream gas outlet be connected to a pressurizer tank through joint flange.Pressurizer tank connects exhaust duct, wherein needs cut-in pressure meter and flowmeter.Flowmeter can be plate hole flowmeter or vortex shedding flow meter.Exhaust duct inserts pressurizer tank again, inserts fan blower again.The effect of pressurizer tank is in order to weaken the charge pulsation of fan blower, and the system that makes moves in steady flow.

During test; Let the fan blower air draught; The pressure differential deltap P that regulates in the pressure gauge through variable valve is a certain value; Read flow and the blade anemoscope rotating speed in the tachometer gage in the flowmeter, can obtain the swirl ratio of gas handling system or roll stream than

and coefficient of flow

according to the formula (4) of front and (5)

Claims (3)

1. a performance of measuring engine aspirating system is steady flow testbed, it is characterized in that a cylinder cover positioning system; It connects a simulation cylinder down; What the simulation cylinder connected that an inside is equipped with that eddy current gas outlet and inside of a blade anemoscope is equipped with a blade anemoscope rolls the stream gas outlet, the eddy current gas outlet with roll the stream gas outlet and be connected to a pressurizer tank jointly, be connected to exhaust duct then; Exhaust duct connects pressure gauge and flowmeter, receives another pressurizer tank again.

2. the performance of measurement engine aspirating system according to claim 1 steady flow testbed is characterized in that, the diameter of described eddy current gas outlet is 2/3rds of the simulation cylinder diameter, and the position is in the simulation cylinder bottom.

3. the performance of measurement engine aspirating system according to claim 1 steady flow testbed; It is characterized in that; The described diameter that rolls the stream gas outlet is 2/3rds of simulation cylinder diameter, and the position is in the side of simulation cylinder, and along the bottom of axis direction of simulation cylinder.

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