CN102155319B - Engine fuel injection control method and engine fuel injection electronic control device - Google Patents

Abstract

The invention discloses an engine fuel injection control method which comprises the following steps of: firstly establishing an oil pressure pulsation working condition table; then obtaining the fuel injection frequency f1 of a current engine according to the working condition of the current engine, and judging whether the working condition of the current engine is the working condition of the oil pressure pulsation in the oil pressure pulsation working condition table, if yes, driving oil injection voltage signals are alternately output to a fuel injector of each cylinder of the engine according to sequence at two time intervals of a first time interval t1 and a second time interval t2, wherein t1 is not equal to t2. The invention also discloses an engine fuel injection electronic control device. The engine fuel injection control method and the engine fuel injection electronic control device can effectively reduce the oil pressure pulsation of the oil rail in the engine and have low cost.

Description

Engine fuel injection control method and engine fuel injection electronic control device

Technical field

The present invention relates to engine technology, particularly a kind of engine fuel injection control method and engine fuel injection electronic control device.

Background technique

Along with the exhaustion day by day of the energy and the continuous enhancing of environmental protection consciousness, people improve constantly for the requirement of automotive engineering.Use electronic fuel injection controlling system on motor, because controlling method is flexible, can realize the accurate control of engine air-fuel ratio, become the standard configuration of passenger car at present.

Electronic fuel injection controlling system, the electric control device (ECU) of take is control centre, utilization is arranged on the various sensors on the motor different parts, record the various running parameters of motor, according to the control program of setting in ECU, by controlling oil sprayer, control accurately fuel injection quantity, make motor can obtain the mixed gas of optium concentration under various operating modes.

The fuel oil of electronic fuel injection controlling system supplies the oil supply rail by fuel pump by pipeline, and oily rail provides enough spaces to store fuel oil, supplies with oil sprayer.Oil sprayer is accepted the instruction of ECU, and requirement in accordance with regulations is to oil spout in intake manifold.

Air inflow is controlled by accelerator pedal control node valve by the driver, the throttle opening difference, and air inflow is also different, and the degree of vacuum in intake manifold is also different, and under same rotating speed, the degree of vacuum of intake manifold becomes certain proportionate relationship with air inflow.Intake manifold pressure sensor can become the change transitions of degree of vacuum in intake manifold the variation of electrical signal, and give ECU, ECU calculates air input of engine by air according to the size of intake manifold vacuum, record calculated signals according to crankshaft position sensor again and go out engine speed, calculate corresponding basic fuel injection amount according to air inflow and tachometer, ECU is according to suction pressure and each cylinder injector of control of engine speed motor, control fuel injection quantity by the endurance of controlling each oil spout, injection duration is longer, fuel injection quantity is larger, the moment of the each oil spout of each cylinder is recorded a certain position signal and controls according to being installed on engine speed (crank position) sensor on clutch housing by ECU.

The mathematical expression that ECU calculates the injection time of the oil sprayer of specifying quiescent flow according to air inflow (motor charging efficiency) is:

Wherein:

Te: injection time, ms;

ρ _air: 1.293g/dm ³air density (0 degree, 1013hPa);

V _hzhl: the discharge capacity of motor one cylinder, the dm of unit ³;

Q _stat: oil sprayer quiescent flow, g/min;

1.05; Correction factor;

L _st: 14.7, chemically correct fuel;

Normmk:0.00001667min/ms unit conversion coefficient;

the motor volumetric efficiency;

λ: fuel injection quantity correction factor;

ε: oil return correction factor;=1, without oil return system; The correction of being correlated with of migration system is arranged.

From above formula, under the operating mode of specific air inflow, the quiescent flow of injection time and oil sprayer is closely related.And the oil pressure in the quiescent flow of oil sprayer and oily rail has close ties, at nominal oil pressure, be p1, nominal quiescent flow is Q _statthe oil sprayer of p1, the quiescent flow when oil pressure is p2 is:

$Q_{\mathrm{stat}}\mathrm{<figure-callout\; id="2"\; label="p"\; filenames="HDA0000064760010000012.png,HDA0000064760010000021.png"\; state="\{\{state\}\}">p</figure-callout>}2=Q_{\mathrm{stat}}\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="HDA0000064760010000012.png,HDA0000064760010000021.png"\; state="\{\{state\}\}">p</figure-callout>}1\&times;\sqrt{\mathrm{<figure-callout\; id="2"\; label="p"\; filenames="HDA0000064760010000012.png,HDA0000064760010000021.png"\; state="\{\{state\}\}">p</figure-callout>}2/p1}---\left(2\right)$

The electronic fuel injection control system, injection time is with the crank angle goniometer.Injection time is converted into to corresponding crankshaft angles, take compression top center as benchmark, set injection advance angle, carry out timing oil spout, the injection advance angle of certain cylinder injector, this cylinder plunger distance is compressed the crank angle that reaches top dead center during this cylinder injector commencement of fuel injection.

Existing electronic fuel injection control system, the fixed position signal that ECU records according to crankshaft position sensor, send and drive the oil spout voltage signal to each cylinder injector of motor, control the oil spout of each cylinder injector, under steady working condition, the commencement of fuel injection of the two adjacent cylinder oil sprayer of motor difference constantly is all identical, and the two adjacent cylinder oil sprayer receives and drives the time lag of oil spout voltage signal identical.Process in the motor operation, the regular quickly opening and closing of each cylinder injector constantly sprays the fuel oil in oily rail, when oil sprayer is opened, fuel oil instantaneous reduction in oil rail pipeline, oil rail overpressure reduces the mineralization pressure ripple, pressure wave is propagated in oily rail with the velocity of sound, when last pressure wave, in propagation process, be rebuffed while reflecting back into spray site, if by chance spray and occur next time, the new pressure wave produced so and the last pressure wave Downward addition reflected, can cause the hydro pulse amplitude to increase considerably, as Fig. 1.Existing electronic fuel injection control system, due to each cylinder injector of motor regular quickly opening and closing at the same time, the new pressure wave that motor produces under some operating mode and the easy Downward addition of last pressure wave reflected, cause the hydro pulse amplitude to increase considerably, the oil pressure while making actual fuel injection deviates from nominal oil pressure far away.

In Fig. 1, ECU sends (during each cylinder injector oil spout) trough in pressure wave while driving the oil spout voltage signal to each cylinder injector, oil pressure is lower, actual fuel injection amount is far below calculating fuel injection quantity, thereby can cause the partially rare of mixed gas, engine mixed gas partially rare, the generation of the abnormal conditions such as will cause deterioration of emission, idling shake, abnormal misfire, catch fire.Therefore, eliminating the hydro pulse in oily rail, make the oil pressure in engine oil rail stable, keep actual oil pressure and nominal oil pressure in engine oil rail to approach, is very important.

Conventional method is to adopt hardware such as changing oil supply system to eliminate the hydro pulse in engine oil rail, as volumes that adopt material that Young's modulus are less, increase oily rail in oily rail pipeline more, change oily rail shape, install oil pressure regulator etc. additional in oily rail, to be used for the adjusting oil pressure in oily rail, make oil pressure keep certain certain value.But above method all can cause the increase of cost.

Summary of the invention

The technical problem to be solved in the present invention is can effectively reduce the hydro pulse in engine oil rail, and cost to be low.

For solving the problems of the technologies described above, the invention provides a kind of engine fuel injection control method, comprise the following steps:

One. set up hydro pulse operating mode table;

Two. obtain present engine fuel oil injection frequency f according to the present engine operating mode ₁, and judge whether the present engine operating mode is the hydro pulse operating mode in described hydro pulse operating mode table, if the hydro pulse operating mode is carried out step 3;

Three. with very first time interval t ₁, the second time lag t ₂two kinds of time lags alternately sequentially export and drive the oil spout voltage signal to each cylinder injector of motor,

t ₁be not equal to t ₂.

In step 2, if the present engine operating mode is not the hydro pulse operating mode, with the 3rd time lag t ₃a kind of time lag output drives the oil spout voltage signal to each cylinder injector of motor,

Engine operating condition comprises engine speed, present engine fuel oil injection frequency f ₁can calculate by following formula:

${\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="HDA0000064760010000012.png,HDA0000064760010000021.png"\; state="\{\{state\}\}">f</figure-callout>}}_1=\frac{n}{60}\&times;0.5\&times;m;$

In formula, n is the present engine rotating speed; M is engine cylinder number.

Preferably, t ₁be at or about 3t ₂.

Preferably, the data item of described hydro pulse operating mode table comprises engine speed, engine load.

For solving the problems of the technologies described above, the present invention also provides a kind of engine fuel injection electronic control device, be provided with a hydro pulse operating mode table in described electric control device, described electric control device obtains present engine fuel oil injection frequency f according to the present engine condition calculating received ₁, and judge whether the present engine operating mode is the hydro pulse operating mode in described hydro pulse operating mode table, if the hydro pulse operating mode, described electric control device is with very first time interval t ₁, the second time lag t ₂two kinds of time lags sequentially alternately export and drive the oil spout voltage signal, otherwise described electric control device is with the 3rd time lag t ₃a kind of time lag output drives the oil spout voltage signal,

t ₁be not equal to t ₂.

Engine operating condition comprises engine speed, present engine fuel oil injection frequency f ₁by following formula, calculate:

${\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="HDA0000064760010000012.png,HDA0000064760010000021.png"\; state="\{\{state\}\}">f</figure-callout>}}_1=\frac{n}{60}\&times;0.5\&times;m;$

In formula, n is the present engine rotating speed; M is engine cylinder number.

Preferably, t ₁be at or about 3t ₂.

Preferably, the data item of described hydro pulse operating mode table comprises engine speed, engine load.

Engine fuel injection control method of the present invention and engine fuel injection electronic control device, when the present engine operating mode is the hydro pulse operating mode, with very first time interval t ₁, the second time lag t ₂two kinds of different time lags (corresponding to two kinds of different crankshaft angles) sequentially alternately export and drive the oil spout voltage signal to each cylinder injector of motor, as shown in Figure 4, and the new pressure wave that makes the oil sprayer oil spout produce and the phase difference of the pressure wave be reflected back

equal or, close to ± (2k+1) π (k=0,1,2,3), new pressure wave is interfered counteracting mutually with the pressure wave be reflected back, and the pressure fluctuation in oily rail is reduced, thereby in engine oil rail, actual oil pressure is approaching with nominal oil pressure.The present invention adopts Software Method to reduce hydro pulse in oily rail, can effectively reduce hydro pulse in oily rail, and basic cost free increases.

The accompanying drawing explanation

Below in conjunction with the drawings and the specific embodiments, the present invention is described in further detail.

Fig. 1 is the schematic diagram that concerns between hydro pulse and actual fuel oil spray;

Fig. 2 is the synthetic schematic diagram of two train waves;

Fig. 3 is engine fuel injection control method one mode of execution schematic diagram of the present invention;

Fig. 4 is the technique effect schematic diagram that one embodiment of the invention obtains.

Embodiment

As shown in Figure 2, suppose the new pressure wave y of injection next time ₁₀with the last pressure wave y fired back ₂₀by wave source S1 and S2, produced respectively, its vibration representation is:

Two train waves propagate into the vibration that the P point causes and are respectively:

A ₁s ₁the Oscillation Amplitude caused at the P point, A ₂s ₂the Oscillation Amplitude caused at the P point, the vibration that P is ordered is the synthetic of equidirectional same frequency vibration.The resultant vibration of ordering at P is:

Wherein:

λ is wavelength, and ripple is propagated the length of one-period.

By above inference, can be obtained, the ripple after the ripple of two same frequencys is synthetic, wave amplitude depends on

be that pressure fluctuation amplitude in oily rail depends on

when the time,

the time, the amplitude minimum.

approach ± (2k+1) π (k=0,1,2,3) also can reduce amplitude.

Engine fuel injection control method one mode of execution of the present invention as shown in Figure 3, comprises the following steps:

One. detect the fuel injection quantity of motor under various operating modes by test, reach a preset proportion (as 5%, 6%) when above due to what the pulsation of oily rail pressure caused actual fuel injection amount to be less than nominal fuel injection quantity under an operating mode, this operating mode belongs to the hydro pulse operating mode, the hydro pulse operating mode be according to test detect obtain due to oily rail pressure pulsation cause actual fuel injection amount be less than nominal fuel injection quantity reach a preset proportion time engine operating condition; According to the test testing result, set up hydro pulse operating mode table, the data item of hydro pulse operating mode table comprises engine speed, engine load etc.;

Two. detect engine operating condition (engine speed, engine load, the speed of a motor vehicle, water temperature, intake temperature etc.), according to the present engine operating mode, obtain present engine fuel oil injection frequency f ₁, and judge that whether the present engine operating mode is the hydro pulse operating mode in described hydro pulse operating mode table, if it is carries out step 3, otherwise carries out step 4; Present engine fuel oil injection frequency f ₁can calculate according to formula (10),

${\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="HDA0000064760010000012.png,HDA0000064760010000021.png"\; state="\{\{state\}\}">f</figure-callout>}}_1=\frac{n}{60}\&times;0.5\&times;m---\left(10\right)$

Wherein, n is the present engine rotating speed; M is the oil sprayer number;

Three. with very first time interval t ₁, the second time lag t ₂two kinds of time lags sequentially alternately export and drive the oil spout voltage signal to each cylinder injector of motor,

t ₁be not equal to t ₂, preferably, t ₁be at or about 3t ₂;

Four. with the 3rd time lag t ₃a kind of time lag output drives the oil spout voltage signal to each cylinder injector of motor,

Engine fuel injection electronic control device one mode of execution of the present invention, be provided with a hydro pulse operating mode table in described electric control device, the data item of hydro pulse operating mode table comprises engine speed, engine load etc., and described electric control device calculates present engine fuel oil injection frequency f according to the present engine operating mode (as engine speed, engine load, the speed of a motor vehicle, water temperature, intake temperature etc.) received ₁(present engine fuel oil injection frequency f ₁can calculate according to formula (10)), and judge whether the present engine operating mode is the hydro pulse operating mode in described hydro pulse operating mode table, if the hydro pulse operating mode, described electric control device is with very first time interval t ₁, the second time lag t ₂two kinds of time lags sequentially alternately export and drive the oil spout voltage signal, otherwise described electric control device is with the 3rd time lag t ₃a kind of time lag output drives the oil spout voltage signal,

t ₁be not equal to t ₂, preferably, t ₁be at or about 3t ₂.

Engine fuel injection control method of the present invention and engine fuel injection electronic control device, when the present engine operating mode is the hydro pulse operating mode, with very first time interval t ₁, the second time lag t ₂two kinds of different time lags (corresponding to two kinds of different crankshaft angles) sequentially alternately export and drive the oil spout voltage signal to each cylinder injector of motor, as shown in Figure 4, and the new pressure wave that makes the oil sprayer oil spout produce and the phase difference of the pressure wave be reflected back

equal or, close to ± (2k+1) π (k=0,1,2,3), new pressure wave is interfered counteracting mutually with the pressure wave be reflected back, and the pressure fluctuation in oily rail is reduced, thereby in engine oil rail, actual oil pressure is approaching with nominal oil pressure.The present invention adopts Software Method to reduce hydro pulse in oily rail, can effectively reduce hydro pulse in oily rail, and basic cost free increases.

Claims (9)

1. an engine fuel injection control method, is characterized in that, comprises the following steps:

One. set up hydro pulse operating mode table;

Two. obtain present engine fuel oil injection frequency f according to the present engine operating mode ₁, and judge whether the present engine operating mode is the hydro pulse operating mode in described hydro pulse operating mode table, if the hydro pulse operating mode is carried out step 3;

Three. with very first time interval t ₁, the second time lag t ₂two kinds of time lags alternately sequentially export and drive the oil spout voltage signal to each cylinder injector of motor, t ₁be not equal to t ₂.

2. engine fuel injection control method according to claim 1, is characterized in that, in step 2, if the present engine operating mode is not the hydro pulse operating mode, with the 3rd time lag t ₃a kind of time lag output drives the oil spout voltage signal to each cylinder injector of motor,

3. engine fuel injection control method according to claim 1, is characterized in that, engine operating condition comprises engine speed, present engine fuel oil injection frequency f ₁by following formula, calculate:

$f_1=\frac{n}{60}\&times;0.5\&times;m;$

In formula, n is the present engine rotating speed; M is engine cylinder number.

4. engine fuel injection control method according to claim 1, is characterized in that, t ₁be at or about 3t ₂.

5. engine fuel injection control method according to claim 1, is characterized in that, the data item of described hydro pulse operating mode table comprises engine speed, engine load.

6. an engine fuel injection electronic control device, is characterized in that, is provided with a hydro pulse operating mode table in described electric control device, and described electric control device obtains present engine fuel oil injection frequency f according to the present engine condition calculating received ₁, and judge whether the present engine operating mode is the hydro pulse operating mode in described hydro pulse operating mode table, if the hydro pulse operating mode, described electric control device is with very first time interval t ₁, the second time lag t ₂two kinds of time lags sequentially alternately export and drive the oil spout voltage signal, otherwise described electric control device is with the 3rd time lag t ₃a kind of time lag output drives the oil spout voltage signal,

t ₁be not equal to t ₂.

7. engine fuel injection electronic control device according to claim 6, is characterized in that, engine operating condition comprises engine speed, present engine fuel oil injection frequency f ₁by following formula, calculate:

$f_1=\frac{n}{60}\&times;0.5\&times;m;$

In formula, n is the present engine rotating speed; M is engine cylinder number.

8. engine fuel injection electronic control device according to claim 6, is characterized in that, t ₁be at or about 3t ₂.

9. engine fuel injection electronic control device according to claim 6, is characterized in that, the data item of described hydro pulse operating mode table comprises engine speed, engine load.

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