Air flow meter signal delay compensation device for engine transient air-fuel ratio

Abstract

The utility model relates to the technical field of engine control, in particular to an air flow meter signal delay compensation device for the transient air-fuel ratio of an engine. Comprising a data acquisition device which comprises sensors arranged in N sections of gas inlet pipes from the gas inlet front end of an engine to a gas inlet valve of the engine and is used for acquiring gas parameters in the multiple sections of gas inlet pipes; n is a positive integer; the delay calculation device is connected with the data acquisition device and obtains total delay time based on the gas parameters; and the delay chip is connected with the delay calculation device and controllably superposes the total delay time to the air flow meter, and the air flow meter outputs delayed flow meter signals. Gas parameters of the multiple sections of gas inlet pipes are collected through the sensors, the time of gas passing through each section of gas inlet pipe is calculated, the total delay time between the gas inlet front end of the engine and the gas inlet valve of the engine is obtained, the total delay time is considered in engine transient control to coordinate the advance, and the overshoot risk in the prior art is avoided.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of engine control, concretely relates to air flowmeter signal delay compensation equipment for engine transient air-fuel ratio. BACKGROUND

[0002] The transient control of engine air-fuel ratio is a relatively complex control for engine management system, and the good or bad of transient control is crucial to the drivability of the whole vehicle.The traditional engine control air-fuel ratio control is that the engine control unit (ECU) estimates the current engine intake and corresponding load by taking the engine intake pressure sensor as a signal source, carries out corresponding fuel injection control, and carries out closed-loop regulation in real time by means of the feedback signal of the exhaust end oxygen sensor to achieve the purpose of vehicle emission and comfortable driving.

[0003] Due to the diversity of vehicle operating conditions, the engine cannot always be in stable conditions, and more often the engine speed and load are always in transient change, for example, starting, acceleration and deceleration and other conditions, the above logic is not timely and forward-looking for the estimation control of engine transient intake, resulting in inaccurate fuel injection under transient conditions, resulting in abnormal engine combustion, affecting the driving experience of the vehicle and related pollutant emissions.

[0004] The current market ECU general control strategy is to directly control the filtered signal read by the air flowmeter, which is not good for transient control, because the air flowmeter is generally installed at the front end of the engine intake, far away from the engine intake valve, and direct use of the read signal for fuel injection will have a certain "over-advance" overshoot risk; At the same time, due to the change of engine operating conditions, the driver needs a certain amount of advance to calculate the target intake flow according to the driver's demand (accelerator pedal), so the actual intake of the engine is also advanced. Therefore, the prior art will cause the problem that the actual intake of the engine does not match the target intake flow. UTILITY MODEL CONTENTS

[0005] The utility model aims at providing air flowmeter signal delay compensation equipment for engine transient air-fuel ratio, solving the above technical problems.

[0006] The technical problems solved by the utility model can be realized by the following technical solutions:

[0007] The air flowmeter signal delay compensation equipment for engine transient air-fuel ratio comprises an air flowmeter arranged at the front end of the engine intake, and further comprises,

[0008] The data acquisition device comprises sensors arranged in N sections of the intake pipe from the front end of the engine intake to the engine intake valve to obtain gas parameters in the multiple sections of the intake pipe; N is a positive integer;

[0009] The delay calculation device is connected to the data acquisition device and obtains the total delay time based on the gas parameters;

[0010] The delay chip is connected to the delay calculation device and controllably adds the total delay time to the air flow meter, and the air flow meter outputs a delayed flow meter signal.

[0011] Preferably, the sensors comprise pressure sensors, and the intake pipe is provided with corresponding pressure sensors, and the gas parameters at least include gas pressure.

[0012] Preferably, the system further comprises a volume database connected to the delay calculation device, and the volume database stores the volume value of each section of the intake pipe, and the delay calculation device calculates the delay time of each section of the intake pipe based on the volume value and the gas pressure.

[0013] Preferably, the delay calculation device is provided with an adder to add the delay times of the N sections of the intake pipe to obtain the total delay time.

[0014] Preferably, the intake pipe comprises,

[0015] A first section of the intake pipe from the front end of the engine intake to the supercharger;

[0016] A second section of the intake pipe from the supercharger to the throttle body of the engine intake manifold;

[0017] A third section of the intake pipe from the throttle body to the engine intake valve.

[0018] Preferably, the air flow meter is provided with a pressure sensing chip to obtain the gas pressure of the first section of the intake pipe, and the pressure sensors comprise a first pressure sensor arranged in the second section of the intake pipe and a second pressure sensor arranged in the third section of the intake pipe.

[0019] Preferably, the sensors further comprise a temperature sensor for detecting the temperature in the intake pipe.

[0020] Preferably, the system further comprises a target intake flow calculation device connected to the air flow meter, and the target intake flow calculation device receives an external torque signal and calculates a target intake flow based on a preset torque-intake flow mapping relationship to adapt the delayed flow meter signal.

[0021] Preferably, the air flow meter is further provided with a waveform recorder for recording a flow meter signal of the air flow meter, and the delay chip is connected to the waveform recorder, and the waveform recorder outputs the delayed flow meter signal based on the superimposed total delay time.

[0022] Preferably, the air flow meter is further provided with a signal processing chip, which is capable of controllably pre-processing the delayed flow meter signal.

[0023] The beneficial effects of the present application are as follows: due to the above technical scheme, the present application collects gas parameters of multiple intake pipes through a sensor, calculates the time of gas passing through each intake pipe, obtains the total delay time between the front end of engine intake and the engine intake valve, and considers the total delay time in the coordination advance of engine transient control, thereby avoiding the "over-advance" overshoot risk in the prior art. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The figure is a schematic diagram of the delayed flow meter signal in the embodiment of the present application.

[0025] Figure 2 The figure is a schematic diagram of the delayed flow meter signal in the embodiment of the present application.

[0026] Figure 3 The figure is a schematic diagram of the delayed flow meter signal in the embodiment of the present application. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0028] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0029] The present application will be further described below with reference to the drawings and specific embodiments, but is not limited by the present application.

[0030] The air flow meter signal delay compensation device for engine transient air-fuel ratio, as shown in Figure 1 , Figure 2 , Figure 3 shown, comprises an air flow meter 1 arranged at the front end of engine intake, and further comprises

[0031] The data acquisition device 2 comprises sensors arranged in N sections of the intake pipe from the front end of the engine intake to the engine intake valve to obtain the gas parameters in the multiple sections of the intake pipe; N is a positive integer;

[0032] The delay calculation device 3 is connected to the data acquisition device 2 and obtains the total delay time based on the gas parameters;

[0033] The delay chip 4 is connected to the delay calculation device 3 and controllably adds the total delay time to the air flow meter 1, and the air flow meter 1 outputs the delayed flow meter signal.

[0034] Specifically, the utility model discloses to the " over-advance " overshoot risk of the air flow meter 1 of prior art in the front end of engine intake, and the engine transient control based on the flow meter signal is more accurate by coordinating the advance amount, the utility model discloses the delay of actual signal reading of air flow meter 1 through the estimation of the volume of flow meter to engine intake valve, and the target flow calculated according to the engine demand torque is balanced according to the signal after the delay, and the real transient intake amount is calculated.

[0035] The utility model is suitable for the engine control system whether being equipped with intake temperature sensor or not, but being equipped with air flow meter 1 signal, and the signal based on air flow meter 1 is used to optimize the engine transient control, and the engine transient control is optimized, and the purpose of optimizing vehicle drivability and emission is finally achieved.

[0036] The utility model discloses through collecting intake manifold pressure and temperature, supercharged pressure, air flow meter 1 (AFM) end intake pressure and temperature and flow, engine speed, charge efficiency and other data, can adopt calibration tool INCA cooperation test bench calibration tool PUMA collection.

[0037] The utility model discloses that the intake section is divided into three sections, and is respectively air flow meter 1 to supercharger 5, supercharger 5 to throttle body 6, throttle body 6 to engine intake valve, according to different section pressure, temperature and volume, the gas passing time is calculated respectively according to flow calculation formula and is added up to final delay, and the real-time periodic update is realized through software method.

[0038] The target intake amount and the flow meter signal after the delay are used to carry out filtering and delay processing, so that the signal after the delay is balanced with the target flow calculated according to the engine demand torque, and the real transient intake amount is calculated.

[0039] The utility model is suitable for the system equipped with air flow meter 1, realizes the accurate control of engine transient condition, and effectively improves the vehicle drivability and emission effect.

[0040] In a more preferred embodiment, the sensor comprises a pressure sensor, and the intake pipe is provided with a corresponding pressure sensor, and the gas parameter at least comprises gas pressure.

[0041] Specifically, the utility model discloses the delay that adopts flow formula calculates, and its principle is as follows,

[0042] First, the ideal gas state equation is,

[0043] pV=nRT

[0044] Wherein, p is gas pressure, V is gas volume, n is the amount of substance, R is ideal gas constant, T is gas temperature (unit is kelvin).

[0045] Mass flow calculation formula is,

[0046] m=ρvA

[0047] Wherein, m is mass flow, ρ is gas density, v is air flow rate, A is the cross-sectional area of inlet pipe pipeline;

[0048] By density mass formula,

[0049]

[0050] The volume flow relationship of gas flowing in the pipeline can be obtained,

[0051] V=vA

[0052] Gas density ρ can be obtained by the ideal gas state equation transformation, expression is,

[0053]

[0054] Wherein, M is gas molar mass.

[0055] Combined with mass flow formula,

[0056]

[0057] The calculation formula of each section gas passing time is,

[0058]

[0059] This formula indicates the time required for gas to pass through a certain section of inlet pipe, wherein t indicates delay time, V indicates the volume of the section of inlet pipe, Q is the volume flow through the section of pipeline, and the volume flow is obtained by the above volume flow calculation formula.

[0060] Further specifically, the utility model divides the inlet pipe into three sections, including,

[0061] The first section of inlet pipe 7 from the front end of engine inlet to supercharger 5;

[0062] A second section of intake pipe 8 from the supercharger 5 to the throttle body 6 of the engine intake manifold;

[0063] A third section of intake pipe 9 from the throttle body 6 to the engine intake valve.

[0064] The gas passing time t1, t2, t3 of each section is calculated respectively, and then added to obtain the final total delay time T, that is

[0065] T=t1+t2+t3

[0066] In a preferred embodiment, a volume database connected to the delay time calculation device 3 is further included, the volume database stores the volume value of each section of the intake pipe, and the delay time calculation device 3 calculates the corresponding delay time of each section of the intake pipe based on the volume value and the gas pressure.

[0067] Specifically, the utility model divides the entire intake section into three sections according to the structural characteristics of the intake system, including,

[0068] A first section of intake pipe 7 from the engine intake front end to the supercharger 5;

[0069] A second section of intake pipe 8 from the supercharger 5 to the throttle body 6 of the engine intake manifold;

[0070] A third section of intake pipe 9 from the throttle body 6 to the engine intake valve.

[0071] The utility model comprehensively considers the characteristics of each section of the intake pipe and performs delay operation respectively, and then obtains the total delay time by calculating the gas passing time of each section.

[0072] In a preferred embodiment, the delay time calculation device 3 is provided with an adder, and the total delay time is obtained by adding the N-section intake delay time.

[0073] In a preferred embodiment, the intake pipe includes,

[0074] A first section of intake pipe 7 from the engine intake front end to the supercharger 5;

[0075] A second section of intake pipe 8 from the supercharger 5 to the throttle body 6 of the engine intake manifold;

[0076] A third section of intake pipe 9 from the throttle body 6 to the engine intake valve.

[0077] In a preferred embodiment, the air flow meter 1 is provided with a pressure sensing chip for obtaining the gas pressure of the first section of intake pipe 7, and the pressure sensor includes a first pressure sensor 21 arranged in the second section of intake pipe 8 and a second pressure sensor 22 arranged in the third section of intake pipe 9.

[0078] Specifically, the utility model discloses a kind of engine intake system real-time monitoring system, including air flow meter 1 (AFM), air flow meter 1 (AFM) end intake pressure and temperature acquisition module, intake manifold pressure and temperature acquisition module, boost pressure acquisition module, engine speed acquisition module, charge efficiency acquisition module and data acquisition module.

[0079] Data acquisition uses calibration tool INCA, and carries out with test bench calibration tool PUMA.

[0080] According to the structural features of the intake system, the utility model divides the entire intake section into three sections, the first section is the volume between air flow meter 1 and supercharger 5, the second section is the volume between supercharger 5 and throttle body 6, and the third section is the volume between throttle body 6 and engine intake valve; The segmentation mode of the utility model is based on the different effects of different components in the intake system on airflow, and the pressure, temperature and volume change law in each section also has some differences, so the above segmentation mode is adopted.

[0081] For each section, the gas passing time is calculated according to the flow calculation formula.

[0082] Taking the first section intake pipe 7 as an example, it is assumed that the volume V1 between air flow meter 1 and supercharger 5 is:

[0083] First, according to the ideal gas state,

[0084] p1V1=nRT1

[0085] The density p1 of the gas in the first section intake pipe 7 is calculated, wherein p1 is the gas pressure of the section pipe, V1 is the volume of the section, n is the amount of substance, R is the ideal gas constant, and T1 is the intake temperature of the section (unit: Kelvin).

[0086] By transformation,

[0087]

[0088] Then, according to the mass flow calculation formula,

[0089] m1=ρ1v1A1

[0090] Wherein, m1 is the mass flow of the section, ρ1 is the gas density of the section, v1 is the air flow rate of the section, and A1 is the cross-sectional area of the first section intake pipe 7 pipe;

[0091] Combined with the gas density formula, the volume flow can be further obtained,

[0092]

[0093] Finally, according to the formula,

[0094]

[0095] The time t1 of the gas passing through the first section of the intake pipe 7 is calculated.

[0096] Similarly, the time t2 and t3 of the gas passing through the second section of the intake pipe 8 (volume V2) and the third section of the intake pipe 9 (volume V3) can be calculated in the same way.

[0097] By adding the times of the gas passing through the three sections of the intake pipe, the total delay time T is finally obtained,

[0098] T=t1+t2+t3

[0099] The utility model discloses in order to adapt to the real-time change of engine working condition, and the calculation result is updated in real time by software method, and the delay time calculation is accurate.

[0100] In a preferred embodiment, the sensor further comprises a temperature sensor for detecting the temperature in the intake pipe.

[0101] In a preferred embodiment, a target intake flow calculation device is further included, connected to the air flow meter 1, the target intake flow calculation device receives an external torque signal, and the target intake flow is calculated based on a preset torque-intake flow mapping relationship to adapt the flow meter signal after delay.

[0102] Specifically, in an actual engine system, the required parameters are obtained by using the above-mentioned data acquisition method, the delay of each part of the intake section is calculated according to the gas flow formula, and under different working conditions (such as starting, acceleration and deceleration, etc.), the relationship between the flow meter signal and the target flow is processed according to the calculation result, the accurate control of the engine transient air-fuel ratio is realized, and the driving experience and the emission performance are improved.

[0103] The utility model discloses according to the demand of driver to engine torque (obtained through accelerator pedal position sensor signal), combines the speed of engine, load and other operating parameters, and utilizes preset torque-intake flow mapping relationship to calculate target intake flow.

[0104] The torque-intake flow mapping relationship is determined in the engine bench test and the whole vehicle calibration process, and is used for the best intake amount of engine required under different torque demands, so as to ensure the power performance, the economy and the emission performance of engine under various working conditions.

[0105] In a preferred embodiment, the air flow meter 1 is further provided with a waveform recorder for recording the flow meter signal of the air flow meter 1, and the delay chip 4 is connected to the waveform recorder, and the waveform recorder outputs the delayed flow meter signal based on the superimposed total delay time.

[0106] In a preferred embodiment, the air flow meter 1 is also provided with a signal processing chip, which can controllably pre-process the delayed flow meter signal.

[0107] Specifically, the signal processing chip filters the waveform signal collected by the air flow meter 1, removes noise and interference in the signal, and improves the accuracy of the signal. The filtering algorithm can use common digital filtering methods, such as Kalman filtering.

[0108] The utility model discloses a filter after air flow meter 1 signal is delayed and handled, makes its delay time and the volume delay time of the estimated flow meter to inlet valve match. Delay processing can be realized through the delay algorithm in digital signal processing technology.

[0109] Finally, the delayed flow meter signal and the target intake flow are balanced and calculated. The specific calculation method can be dynamic adjustment according to the difference between the two, for example, using proportional-integral-derivative (PID) control algorithm, by continuously adjusting the fuel injection pulse width and other control parameters, the actual intake gradually approaches the target intake flow, so as to calculate the real transient intake.

[0110] In a specific embodiment,

[0111] This embodiment is on a test bench of an engine equipped with an air flow meter 1 and a supercharging system, starts the INCA calibration tool and the PUMA bench calibration tool, sets the data acquisition parameters, and starts collecting intake manifold pressure and temperature, supercharging pressure, AFM end intake pressure and temperature and flow, engine speed, charge efficiency and other data.

[0112] According to the technical specifications of the engine and the actual structural size of the intake system, the volumes V1, V2 and V3 of the three sections (between the flow meter and the supercharger 5, between the supercharger 5 and the throttle body 6, and between the throttle body 6 and the engine intake valve) are determined, as well as the cross-sectional areas A1, A2 and A3 of the pipes in each section. At the same time, the molar mass of the gas and the ideal gas constant and other constant parameters are obtained, and corresponding settings are made in the control system. The volume and cross-sectional area are known.

[0113] According to the calculation method of the estimated volume delay of the flow meter to the intake valve, the data collected is used to calculate the gas passing time t1, t2 and t3 of each section, and the total delay time T is obtained; and in the calculation process, the change of data is monitored in real time.

[0114] The signal collected by the air flow meter 1 is filtered, Kalman filtering algorithm is used, filter parameters are set, and high-frequency noise and interference in the signal are removed. According to the calculated delay time, the filtered signal is delayed to match the delay of the actual intake process.

[0115] The driver's torque demand signal is acquired through an accelerator pedal position sensor, combined with engine speed and load signals, and the target intake flow is calculated according to a torque-intake flow mapping relationship stored in advance in the ECU.

[0116] The delayed flow meter signal and the target intake flow are input into a PID controller, the PID parameters (proportion coefficient, integral time and differential time) are set, the adjustment amount of the injection pulse width is calculated through the PID algorithm, so that the actual intake amount is adjusted to make the actual intake amount close to the target intake flow. During the engine operation, the deviation between the actual intake amount and the target intake flow is continuously monitored, and the PID parameters are dynamically adjusted to ensure accurate transient air-fuel ratio control under different working conditions.

[0117] The above only describes the preferred embodiments of the present application, and does not limit the implementation and protection scope of the present application. For those skilled in the art, it should be realized that any equivalent replacement and obvious changes made according to the content of the present application should be included in the protection scope of the present application.

Claims

1. An air flow meter signal delay compensation device for engine transient air-fuel ratio, comprising an air flow meter (1) arranged at the front end of engine intake, characterized in that, Also comprising, a data acquisition device (2) comprising sensors arranged in N sections of an intake pipe from an engine air intake front end to an engine intake valve, to obtain gas parameters in the multiple sections of the intake pipe; N is a positive integer; a delay calculation device (3) connected to the data acquisition device (2), to obtain a total delay time based on the gas parameters; a delay chip (4) connected to the delay calculation device (3), to controllably superimpose the total delay time to the air flow meter (1), and the air flow meter (1) outputs a delayed flow meter signal.

2. The air flow meter signal delay compensation apparatus of claim 1, wherein, The sensors include pressure sensors, and the intake pipe is provided with corresponding pressure sensors, and the gas parameters at least include gas pressure.

3. The air flow meter signal delay compensation apparatus of claim 2, wherein, Further comprising a volume database connected to the delay calculation device (3), and the volume database stores volume values of each section of the intake pipe, and the delay calculation device (3) calculates a delay time corresponding to each section of the intake pipe based on the volume values and the gas pressure.

4. The air flow meter signal delay compensation apparatus of claim 3, wherein, The delay calculation device (3) is provided with an adder to obtain the total delay time by adding N section intake delay times.

5. The air flow meter signal delay compensation apparatus of claim 2, wherein, The intake pipe comprises, a first section of the intake pipe (7) from the engine air intake front end to a supercharger (5); a second section of the intake pipe (8) from the supercharger (5) to a throttle body (6) of an engine intake manifold; a third section of the intake pipe (9) from the throttle body (6) to the engine intake valve.

6. The air flow meter signal delay compensation apparatus of claim 5, wherein, The air flow meter (1) is provided with a pressure sensing chip to obtain the gas pressure of the first section of the intake pipe (7), and the pressure sensors include a first pressure sensor arranged in the second section of the intake pipe (8) and a second pressure sensor arranged in the third section of the intake pipe (9).

7. The air flow meter signal delay compensation apparatus of claim 1, wherein, The sensors further include temperature sensors for detecting the temperature in the intake pipe.

8. The air flow meter signal delay compensation apparatus of claim 1, wherein, Further comprising a target intake flow calculation device connected to the air flow meter (1), the target intake flow calculation device receives an external torque signal and calculates a target intake flow based on a preset torque-intake flow mapping relationship to adapt the delayed flow meter signal.

9. The air flow meter signal delay compensation apparatus of claim 1 wherein, The air flow meter (1) is further provided with a waveform recorder for recording the flow meter signal of the air flow meter (1), and the delay chip (4) is connected to the waveform recorder, and the waveform recorder outputs the delayed flow meter signal based on the superimposed total delay time.

10. The air flow meter signal delay compensation apparatus of claim 1, wherein, The air flow meter (1) is further provided with a signal processing chip, which can controllably preprocess the delayed flow meter signal.

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