CN101566108A

CN101566108A - Control system for determining mass air flow

Info

Publication number: CN101566108A
Application number: CNA2008101497707A
Authority: CN
Inventors: N·J·卡尔维特; L·K·维金斯; Q·马
Original assignee: GM Global Technology Operations LLC
Current assignee: GM Global Technology Operations LLC
Priority date: 2008-04-23
Filing date: 2008-09-25
Publication date: 2009-10-28
Anticipated expiration: 2028-09-25
Also published as: DE102008039559A1; CN101566108B; DE102008039559B4

Abstract

The present invention relates to a control system for determining mass air flow. In particular a system and a method are provided, the system comprises receiving a mass air flow signal having a frequency that varies based on mass air flow in an intake manifold of an engine, determining first period data from the mass air flow signal, deriving first mass data for the mass air flow signal based on the first period data, cumulating the first period data and the first mass data for N cylinder events, wherein N is an integer greater than 1, and calculating a mass air flow between the N cylinder events from the cumulated first period data and the cumulated first mass data.

Description

Be used for determining the control system of Mass Air Flow

The cross reference of related application

[0001] the application requires the U.S. Provisional Application No.60/958 of submission on July 2nd, 2007, and 065 rights and interests are incorporated its full content into this paper at this with way of reference.

Technical field

[0002] the present invention relates to automotive control system, particularly relate to the method and system of the quality control flow that is used for definite automobile.

Background technique

[0003] statement of this section may not constitute prior art just for the background information relevant with the present invention is provided.

[0004] sensor is collected from the information of each parts of engine system.This information is received by control module, and this control module is controlled engine system according to received information.For example, quality control flow (MAF) sensor can be measured Mass Air Flow.This maf sensor can have square wave output.The frequency of maf sensor output can change with respect to the Mass Air Flow that flows to maf sensor.Relation between maf sensor output signal frequency and the Mass Air Flow can be known, so just can utilize the question blank of Mass Air Flow and frequency to search Mass Air Flow under the characteristic frequency.

[0005] Mass Air Flow that records of control module utilization is controlled fuel and is sprayed.Know that the Mass Air Flow that enters cylinder between the specific cylinder events may be useful.Cylinder events can be the cylinder intake incident, also can be called low resolution (low resolution, LORES) incident.Some systems utilize the mean frequency between the cyclical event to determine Mass Air Flow.This mean frequency is as the index of the question blank of Mass Air Flow and frequency.Yet the technology of averaging may not solve concern between Mass Air Flow and the frequency non-linear, therefore may produce incorrect average quality air mass flow.

[0006] the another kind of method of determining the Mass Air Flow between the cylinder events is that frequency axis with the question blank of Mass Air Flow and frequency converts the cycle axle to.This conversion is that the pass with frequency (circulation/second) and cycle (second/circulation) is basic.Mass Air Flow also can convert quality to according to Mass Air Flow (quality/second), quality and the relation between the cycle.Timing module can receive each circuit cycle of MAF output signal and measurement signal.The question blank in quality and cycle can be used for determining quality according to the cycle by timing module.Add up quality and cycle between the cylinder events then.

[0007] the maf sensor signal may be also asynchronous with cylinder events, and like this, the part MAF signal cycle of not calculating (signal cycle) between the cylinder events may have error.Error size is cycle of comparing with cumulative time based on the part signal between the cylinder events.The automobilism condition maf sensor output may occur and be in the situation that low frequency (low quality air mass flow just) and cylinder events are frequently carried out (high RPM just).The maf sensor output signal circulation that each cylinder events can be carried out lesser amt for example 5, like this, local signal may produce very large error.

[0008], shows the sequential chart of the possible error that causes by cylinder events and maf sensor output timing, and indicate with reference character 10 on the whole with reference to Fig. 1.Among Fig. 1, when the trailing edge of maf sensor output and cylinder (LORES) when incident is alignd, each cylinder events has five complete maf sensors to export pulses.Yet,, occurring five pulses between first and second cylinder events and four pulses between the second and the 3rd cylinder events, occurring so if mass air flow meter carries out based on the trailing edge of the output of maf sensor 34 at last.This may cause identical gross mass air mass flow is produced different Mass Air Flow readings.

[0009] referring now to Fig. 2, curve Figure 12 figure has released the sampling error in exemplary 8 Cylinder engines, and this motor has engine RPM (rpm) value of variation and the maf sensor frequency values that changes.95% or higher precision can be considered to acceptable.This precision is based on percentage of time, calculates in engine running and can not produce error.Fig. 2 shows precision and has dropped under the tolerance interval in high-engine RPM level and/or low maf sensor output frequency level place.For example, the maf sensor frequency be 1000 and engine RPM be about 3300 places, precision is about 75%.

[0010] referring now to Fig. 3, curve Figure 14 figure has released the sampling error in exemplary 4 Cylinder engines, and this motor has the engine RPM value of variation and the maf sensor frequency values of variation.95% or higher precision can be considered to acceptable.This precision is based on percentage of time, calculates in engine running and can not produce error.Curve Figure 14 shows precision and has dropped under the tolerance interval in high-engine RPM level and/or low maf sensor output frequency level place.For example, the maf sensor frequency be 1000 and engine RPM be about 6500 places, precision is about 77%.

Summary of the invention

[0011] a kind of method comprises: quality of reception air flow rate signal, and this Mass Air Flow signal has the frequency that changes according to the Mass Air Flow in the engine intake manifold; Determine the period 1 data according to the Mass Air Flow signal; Derive first qualitative data according to the period 1 data for the Mass Air Flow signal; The period 1 data and first qualitative data of accumulative total N cylinder events, wherein, N is the integer greater than 1; And according to the Mass Air Flow between first qualitative data calculating N cylinder events of period 1 data that add up and accumulative total.

[0012] a kind of control system, comprise: timing module, this timing module quality of reception air flow rate signal, this signal has the frequency that changes according to the Mass Air Flow in the engine intake manifold, this timing module is determined the period 1 data according to the Mass Air Flow signal, this timing module is derived first qualitative data according to the period 1 data, and this timing module also adds up the period 1 data and first qualitative data; With the Mass Air Flow module, this Mass Air Flow module is according to first qualitative data of accumulative total and the Mass Air Flow of the period 1 data computation N cylinder events of accumulative total, and wherein, N is the integer greater than 1.

[0013] will obviously find out more suitable application areas of the present invention from the description of this paper.Should be appreciated that detailed description and specific examples have just illustrated the preferred embodiments of the present invention, only be used as the effect of example, rather than limit the scope of the invention in order to be intended to.

Description of drawings

[0014] can understand the present invention more fully according to the detailed description and the accompanying drawings, wherein:

[0015] Fig. 1 is the figure that figure has released the sampling error of Mass Air Flow measurement;

[0016] Fig. 2 is that figure has released the plotted curve for the potential sampling error of RPM value in 8 Cylinder engines that changes;

[0017] Fig. 3 is that figure releases the plotted curve of knowing clearly for the potential sampling error of RPM value in 4 Cylinder engines that changes;

[0018] Fig. 4 is the functional block diagram of engine system;

[0019] Fig. 5 is the functional block diagram of the control module of engine system;

[0020] Fig. 6 is that figure has released the plotted curve of the exemplary output of maf sensor as the function of frequency;

[0021] Fig. 7 is the plotted curve of Mass Air Flow as the function of the frequency of exemplary quality air flow sensor;

[0022] Fig. 8 is the plotted curve of Mass Air Flow as the function in the cycle of exemplary quality air flow sensor;

[0023] Fig. 9 is the plotted curve of quality as the function in the cycle of exemplary quality air flow sensor; And

[0024] Figure 10 is the flow chart that figure has released the operation of the control system that is used for definite Mass Air Flow.

Embodiment

[0025] in fact following description is exemplary, determines to limiting the present invention and application or purposes unintentionally by any way.For the sake of clarity, represent identical cloth spare with identical reference character in the accompanying drawing.Term used herein " module " and/or " device " are meant specific integrated circuit (ASIC), electronic circuit, carry out the processor of one or more softwares or firmware program that (shared, special-purpose or in groups) and storage, combinational logic circuit and/or other provide the suitable parts of described function.

[0026], wherein shows the engine system 15 of the Mass Air Flow system that adopts the application referring now to Fig. 4.Engine system 15 can comprise motor 16 and control module 17.Motor 16 can comprise a plurality of cylinders 18, and each cylinder all has one or more intake valves and/or exhaust valve (not shown).In running, cylinder (or LORES) incident of regulation can be used for the calculating of Mass Air Flow based on engine position sensor ring (EPSR) 32, and wherein the engine position sensor ring can be determined motor 16 each position component according to the position of bent axle (not shown).

[0027] engine system 15 also can comprise fuel injection system 20, provides fuel with the cylinder to motor 16.Motor 16 can receive the air that burns with the fuel from fuel system 20 to drive the piston (not shown) of motor 16.Electronic Throttle Control (ETC) module 26 can be adjusted closure blade 27 in the intake manifold 28 according to the position of accelerator pedal 30, and carries out throttle control algorithms by ETC module 26.The position of accelerator pedal 30 can be detected by accelerator pedal sensor 40, produces pedal position signal, by with the transmission of control module 17 this signal being exported to ETC module 26.The position of braking pedal 44 can be detected by brake pedal sensor 48, produces the brake pedal position signal, by with the transmission of control module 17 this signal being exported to ETC module 26.

[0028] Mass Air Flow or the quality of determining to flow between the cyclical event air of cylinder 18 may be that people expect.Like this, the air of the cylinder 18 of supply engine 16 just can be known or controlled, and the fuel that these numerical value can be used for providing suitable sprays to obtain the required expectation air/fuel mixture of burning.Mass Air Flow (MAF) sensor 34 can detect the air that enters motor 16 via intake manifold 28.Maf sensor 34 produces voltage according to Mass Air Flow, and this voltage can be imported the voltage controlled oscillator of maf sensor 34.Maf sensor 34 output signals then, this signal have the frequency that increases with Mass Air Flow input (representing with voltage).

[0029] frequency of maf sensor 34 and the relation between the Mass Air Flow can be known, and can be converted into the question blank in quality and cycle.The question blank in this quality and cycle can be stored in the storage of timing module 36.Timing module 36 can be an independently module, perhaps can be parts of control module 17.Timing module 36 can be to control module 17 or its parts Transfer Quality and periodic quantity.Control module 17 can utilize these to be worth to determine Mass Air Flow between the cylinder events.Mass Air Flow between the cylinder events can be used for controlling the function of motor 16, for example sprays from the fuel of fuel injection system 20 to cylinder 18.

[0030] cylinder events can be based on the output of EPSR 32.EPSR 32 can comprise that the position of bent axle (not shown) that can detection of engine 16 is as detecting the sensor of the tooth position on the bent axle.Just can determine the position of piston in each cylinder 18 of motor 16 according to crank position.For example, a typical LORES incident being associated with cylinder events can be based on piston position, and it is in the scope of 68 °-78 ° of for example budc (bTDC) that EPSR 32 records.The output of EPSR 32 also can be used for the transit time between definite cylinder events.

[0031] in the control that the function (for example fuel injection) of motor 16 is carried out, control module 17 also can be considered other input.Exhaust sensor 50 and system sensor 52 can be received by control module 17.System sensor 52 can be for example temperature transducer or baroceptor and other conventional sensors and/or controller signals.The output of motor 16 can be connected with front-wheel and/or trailing wheel with speed changer 60 by torque converter 58.

[0032], illustrates in greater detail control module 17 and timing module 36 referring now to Fig. 5.Concerning Fig. 5, timing module 36 is illustrated as parts of control module 17.Control module 17 can provide the function of determining Mass Air Flow, and comprises timing module 36, Mass Air Flow (MAF) module 80 and other control module 84.Timing module 36 can comprise data accumulative total module 82, quality conversion module 86 and puocessing module 88.

[0033] timing module 36 provides the mass air flow meter of the first order to calculate, and discharges the interior processing time of other processor of control module 17.The puocessing module 88 of timing module 36 can receive from the signal of maf sensor 34 and the signal period of measuring each signal cycle.Quality conversion module 86 can will convert qualitative data to from the cycle data of handling module 88.For example, quality conversion module 86 can be a question blank, and comprises quality and the cycle data that is used for maf sensor 34.Puocessing module 88 can be communicated with quality conversion module 86 to receive the magnitude in mensuration cycle.Puocessing module 88 is communicated with data accumulative total module 82 then with up-to-date quality and periodic quantity and always quality measurement and the continuous integration value in cycle add up.Puocessing module 88 can will pass to MAF module 80 from the aggregate-value of data accumulative total module 82 according to the request from MAF module 80.

[0034] in the expectation moment of the cylinder events of indicating based on EPSR 32, MAF module 80 can be communicated with puocessing module 88 to receive accumulative total quality and cycle data.MAF module 80 can be determined the time that cylinder events occurs according to the output of EPSR 32.In each cylinder events, but MAF module 80 query processing module 88 are used for the accumulative total quality and the cycle data of this cylinder events with reception.MAF module 80 is determined gross mass or Mass Air Flow between the cyclical event based on the transit time between accumulative total quality and cycle data and the cylinder events then.

[0035] MAF module 80 can send quality and Mass Air Flow to other control module 84.Other control module 84 can comprise that those utilize Mass Air Flow information to determine the control module that combustion parameter such as fuel spray.For example, another control module 84 can spray into the expectation air/fuel mixture of fuel quantity to be kept for burning in the cylinder 18 of motor 16 according to Mass Air Flow correction.

[0036] referring now to Fig. 6, this plotted curve shows the example frequency output that is used for exemplary quality air mass flow pattern, and is denoted as reference character 90 on the whole.Maf sensor output is depicted as the signal of bottom and can is square wave.As shown in Figure 6, corresponding LORES value of each cylinder events.When the Mass Air Flow that flows through maf sensor increased, the maf sensor output signal frequency also increased.The cycle relevant with the complete cycle of maf sensor 34 reduces along with the increase of Mass Air Flow.

[0037] referring now to Fig. 7, curve Figure 92 has described the frequency of exemplary maf sensor 34 and the relation between the Mass Air Flow.Frequency can be on the x axle, and is unit with kilohertz (kHz).Mass Air Flow can be on the y axle, and is unit with Grams Per Second (g/s).As shown in Figure 7, the output of the frequency of maf sensor 34 is along with Mass Air Flow increases with nonlinear way.This is the method that most maf sensor 34 MANUFACTURER provide relevant maf sensor 34 information.

[0038] referring now to Fig. 8, curve Figure 94 has described the cycle of exemplary maf sensor 34 and the relation between the Mass Air Flow.Curve Figure 94 can determine according to frequency (circulation/second) and the relation between the cycle (second/circulation) from curve Figure 92.Cycle can be on the x axle and is unit with millisecond (ms).Mass Air Flow can be a unit on the y axle and with g/s.If the circuit cycle is short more, the circuit Mass Air Flow is just high more.Curve Figure 94 is useful to determining Mass Air Flow, because the signal that receives from maf sensor 34 can be the cycle, can record this cycle at an easy rate by the continuous rising edge of definite signal or the time between the trailing edge.

[0039] referring now to Fig. 9, curve Figure 96 has described the quality of exemplary maf sensor 34 and the relation between the cycle.Curve Figure 96 can determine quality in this specific period by the Mass Air Flow of the Grams Per Second in certain cycle this periodic quantity with millisecond on duty from curve Figure 94.Cycle can be on the x axle and is unit with millisecond (ms).Quality can be a unit on the y axle and with mg.Cycle data can be recorded by the puocessing module 88 of timing module 36 rising edge or the trailing edge according to the signal of maf sensor 34.The cycle that the puocessing module 88 of timing module 36 records is short more, and this circuit quality is just big more.The information of curve Figure 96 can be used for generating the question blank of quality conversion module 86.The information in quality and cycle is useful to determining the gross mass air mass flow between the cylinder events, because the unit (quality and time) that can add up between the cylinder events determines gross mass air mass flow (quality of time per unit).

[0040] referring now to Figure 10, this flow chart description is known clearly and is used for each step that quality between the cylinder events and mass air flow meter are calculated in the control logic 100.Control logic 100 can begin at step 102 place.At step 102 place, MAF module 80 can monitor the output of the EPSR 32 that is used for new cylinder events.When new cylinder events having occurred, MAF module 80 is just stored the time of this cylinder events, and control logic 100 proceeds to square frame 103.If do not occur, control logic 100 just constantly centers on square frame 102 circulations up to running into first cylinder events.At square frame 103 places, MAF module 80 can be inquired about the puocessing module 88 of timing module 36 to obtain benchmark accumulative total quality and time data.Perhaps, MAF module 80 can be communicated by letter with puocessing module 88, so that all are added up quality and time data zero clearing.Control logic 100 proceeds to square frame 104 then to wait for the trailing edge from maf sensor 34.

[0041] at square frame 104 places, the trailing edge that puocessing module 88 is waited for from maf sensor 34.Perhaps, puocessing module 88 can be waited for the rising edge from maf sensor 34.If what adopt is trailing edge, control logic 100 just constantly circulates up to receiving trailing edge around square frame 104 so.In case receive trailing edge, puocessing module 88 just picks up counting up to next trailing edge, and proceeds to square frame 105.At square frame 105 places, puocessing module 8g waits for the next trailing edge from maf sensor 34.Next trailing edge has appearred in 105 places when square frame, and control logic 100 just proceeds to square frame 106.Control logic 100 can circulate up to next trailing edge occurring around step 105 continuously.

[0042] at step 106 place, puocessing module 88 determine maf sensors 34 output at last trailing edge and the transit time between this trailing edge (circulation just) is determined this circuit cycle recently.Control logic 100 advances to step 108 then.At step 108 place, puocessing module 88 utilizes the quality conversion module 86 of timing module 36 to determine the air quality (mg) that is associated with the up-to-date circuit cycle.Quality conversion module 86 comprises a chart that is used for cycle data is converted to qualitative data, as curve Figure 96.Control logic 100 advances to step 110.

[0043] at step 110 place, puocessing module 88 exists up-to-date quality and periodic quantity in the data accumulative total module 82 of timing module 36.Data accumulative total module 82 comprises the continuous integration to total air quality and time.This continuous integration is realized by up-to-date quality and time value are added on the previous aggregate-value.Control logic 100 proceeds to square frame 112.At square frame 112 places, MAF module 80 monitors that EPSR 32 is to determine whether to occur another cylinder events.Step 105 to 112 can continue to wait for trailing edge, calculate cycle between the trailing edge, determine that quality in this cycle and accumulative total quality and cycle data are up to another cylinder events occurring.In case another cylinder events occurs, MAF module 80 is just stored the time of cylinder events, and control logic 100 proceeds to step 114.

[0044] at step 114 place, the puocessing module 88 of MAF module 80 inquiry timing modules 36 is to obtain up-to-date accumulative total quality and time value from data accumulative total module 82.Control logic 100 advances to step 116 then.At step 116 place, MAF module 80 obtains previous accumulative total quality and the time value relevant with previous cylinder events.MAF module 80 is then from previous accumulative total quality with deduct up-to-date accumulative total quality the time and the time is determined quality and time between two up-to-date cylinder events.Control logic 100 advances to step 118 then.

[0045] at step 118 place, MAF module 80 is determined average quality air mass flow between two cylinder events with the quality between two cylinder events divided by the time between two cylinder events.If expect the gross mass value, MAF module 80 just multiply by the average quality air mass flow between two cylinder events total transit time of being determined by the signal of EPSR 32.MAF module 80 sends these numerical value to other the control module 84 that is used for automobile operation (spraying as fuel).Control is just got back to step 105 then and is continued to measure quality and cycle up to next cylinder events occurring.

[0046] those skilled in the art can recognize according to description above now, can implement broad teachings of the present invention in a variety of forms.Therefore, although described the present invention with specific examples,, therefore actual range of the present invention can not be restricted, because can clearly obtain other modification by research accompanying drawing, specification and following claim for a person skilled in the art.

Claims

1, a kind of method comprises:

Quality of reception air flow rate signal, this Mass Air Flow signal has the frequency that changes according to the Mass Air Flow in the engine intake manifold;

Determine the period 1 data according to the Mass Air Flow signal;

First qualitative data according to period 1 data derivation Mass Air Flow signal;

The period 1 data and first qualitative data of storage N cylinder events, wherein, N is the integer greater than 1; And

Calculate Mass Air Flow between the N cylinder events according to the period 1 data of being stored and first qualitative data stored.

2, the method for claim 1 also comprises:

Determine the second round between the N cylinder events; And

Calculate second quality between the N cylinder events according to the product of the Mass Air Flow that calculates and this second round.

3, method as claimed in claim 2 wherein, determines to be based on second round between the N cylinder events that the engine position sensor ring signal carries out.

4, method as claimed in claim 3, wherein, this engine position sensor ring signal represents that piston is positioned at the scope of 68 °-78 ° of budc.

5, determine that the method for claim 1, wherein the period 1 data comprise the definite period 1 data of Mass Air Flow signal between the continuous transformation of negative slope.

6, the method for claim 1, wherein the Mass Air Flow signal is a square signal.

7, method as claimed in claim 6 wherein, determines that the period 1 data are to carry out between the trailing edge of Mass Air Flow signal changes.

8, first qualitative data of the method for claim 1, wherein deriving comprises based on the period 1 data form with first qualitative data is carried out index.

9, method as claimed in claim 8, wherein, the calculating of Mass Air Flow comprises that first qualitative data that will be stored is divided by the period 1 data of being stored.

10, the method for claim 1 also comprises based on the Mass Air Flow of calculating and adjusts engine operating parameter.

11, a kind of control system of motor comprises:

Timing module, this timing module quality of reception air flow rate signal, this signal has the frequency that changes according to the Mass Air Flow in the engine intake manifold, this timing module is determined the period 1 data according to the Mass Air Flow signal, this timing module is according to period 1 data first qualitative data of deriving, and this timing module is also stored the period 1 data and first qualitative data; With

The Mass Air Flow module, this Mass Air Flow module is according to the Mass Air Flow of first qualitative data of being stored with the period 1 data computation N cylinder events of being stored, and wherein, N is the integer greater than 1.

12, control system as claimed in claim 11, wherein, the Mass Air Flow module determine between the N cylinder events second round and according to derive second quality between the N cylinder events of the product of the Mass Air Flow of calculating and this second round.

13, control system as claimed in claim 12, wherein, the Mass Air Flow module is determined second round based on the engine position sensor ring signal.

14, control system as claimed in claim 13, wherein, this engine position sensor ring signal represents that piston is positioned at the scope of 68 °-78 ° of budc.

15, control system as claimed in claim 11, wherein, the period 1 of period 1 data is to select between the continuous transformation of negative slope at the Mass Air Flow signal.

16, control system as claimed in claim 11, wherein, the Mass Air Flow signal is a square signal.

17, control system as claimed in claim 16, wherein, the period 1 of period 1 data is to select between the trailing edge of Mass Air Flow signal changes.

18, control system as claimed in claim 11, wherein, timing module comprises:

The quality conversion module, this quality conversion module is based on period 1 data first qualitative data of deriving; With

Data accumulative total module, these data accumulative total module accumulative total first qualitative data and period 1 data.

19, control system as claimed in claim 18, wherein, the quality conversion module comprises question blank, it is first qualitative data of index that this question blank has with the period 1 data.

20, control system as claimed in claim 11, the Mass Air Flow module is come the calculated mass air mass flow with first qualitative data of being stored divided by the period 1 data of being stored.