A correction control method for calculating fuel injection quantity at different altitudes for a port injection engine

Abstract

The present invention specifically relates to a correction control method for calculating the fuel injection amount at different altitudes of a port injection engine, a pressure correction control method for optimizing the fuel injection amount under different environmental pressures, a correction curve of the intake manifold pressure and the oil rail pressure difference is creatively introduced in the model calculation, and the correction value at different altitudes and different intake manifold pressures is accurately calibrated to ensure that the air-fuel ratio can be controlled at a theoretical optimal level at different altitudes. The present invention is based on a large amount of road test data, including measurements at different ambient temperatures and different altitudes. Through big data statistical cluster analysis, it is found that the key factor affecting the accurate calculation of the fuel amount of the port injection engine is the pressure difference between the oil rail pressure and the intake manifold. Through this method, on the one hand, the fuel economy at high altitudes can be reduced, while ensuring high power output in plateau environments.

Description

Technical Field

[0001] The invention relates to the technical field of energy conservation and environmental protection, and in particular to a correction control method for calculating the fuel injection amount of an airway injection engine at different altitudes. Background Art

[0002] At present, the oil circuit calculation of most airway injection and direct injection engines is based on the predicted load, and the fuel density is corrected by the model temperature to ensure the accuracy of the fuel pre-control amount at different ambient temperatures. However, considering the actual application scenarios of users, in addition to different ambient temperatures, the influence of different atmospheric pressures on the calculation of fuel injection amount also needs to be included in the model calculation. The oil circuit calculation of most airway injection and direct injection engines in the prior art is based on the predicted load, and the fuel density is corrected by the model temperature to ensure the accuracy of the fuel pre-control amount at different ambient temperatures. However, considering the actual application scenarios of users, in addition to different ambient temperatures, the influence of different atmospheric pressures on the calculation of fuel injection amount also needs to be included in the model calculation. Through the big data analysis in the actual vehicle road test calibration process, it is found that the correction method has a high air-fuel ratio control accuracy in the steady-state working condition on the plain, but with the increase in altitude, the air-fuel ratio continues to lean towards the rich end, that is, the amount of fuel injected is more than the demand, which leads to increased fuel consumption. Summary of the invention

[0003] Therefore, the technical problem to be solved by the present invention is to overcome the defects of the prior art in that the fuel correction accuracy in plateau environment is poor and the oil consumption of the whole vehicle is increased in plateau environment, thereby providing a correction control method for calculating the fuel injection amount of an airway injection engine at different altitudes.

[0004] A correction control method for calculating the fuel injection amount of a port injection engine at different altitudes comprises the following steps:

[0005] Step 1: Fix the test vehicle on the rotating hub for calibration in a plain area;

[0006] Step 1.1 Set the hub to speed mode, calibrate the engine control to open loop, adjust the initial engine speed, and start data collection when the engine water temperature reaches at least the specified temperature;

[0007] Step 1.2: gradually increase the opening of the engine throttle. As the throttle opening increases, the intake manifold pressure also increases. When the intake manifold pressure reaches the initial specified value, the correction coefficient a1 of the operating point is corrected to make the open-loop air-fuel ratio equal to 1. After a period of stability, the a1 value is determined to be locked.

[0008] Step 1.3: Increase the intake manifold pressure to a fixed value for multiple times. Each time the intake manifold pressure is increased to a fixed value, step 1.2 is repeated until the calibration of a2 to a9 is completed.

[0009] Step 1.4: Increase the engine speed to a fixed value for multiple times. Each time the engine speed is increased to a fixed value, repeat the steps 1.2 and 1.3. If the calibration result measured varies by more than 5% from the calibration result measured at the initial engine speed, the average value a[i] of the calibration result measured at the initial engine speed and the calibration result measured by adjusting the engine speed for multiple times is taken.

[0010] Step 1.5 After completing the scanning of the above steps, solidify the calibration data and perform calibration verification on the second test vehicle. If the open-loop air-fuel ratio of the two test vehicles can be controlled within the standard range, it is considered that the basic calibration is completed;

[0011] Step 2: Calibrate on plateau roads;

[0012] Step 2.1 Select a long straight section on the plateau road, and start data collection when the engine water temperature reaches at least the specified temperature. Repeat steps 1.2 to 1.3, and the calibration data are recorded as b1 to b9;

[0013] Step 2.2 performs calibration in different plateau environments, repeating step 2.1, and the calibration data are recorded as c1 to c9, d1 to d9, and e1 to e9;

[0014] Step 3: Fill the calibration coefficients into the calibration coefficient table and write the table into the engine control unit ECU.

[0015] Furthermore, the initial engine speed is 2000 rpm.

[0016] Furthermore, the initial prescribed value of the intake manifold pressure is 400 bpa.

[0017] Furthermore, the specific values ​​of increasing the intake manifold pressure to a fixed value multiple times are 500bpa, 600bpa, 700bpa, 800bpa, 900bpa, 1000bpa, 1200bpa and 1400bpa.

[0018] Further, the engine speed is increased multiple times to specific values ​​of fixed values, namely, 2500 rpm, 3000 rpm, 4000 rpm and 5000 rpm.

[0019] Further, the standard range is 0.95 to 1.05.

[0020] Furthermore, the engine water temperature is set to 80 degrees.

[0021] Furthermore, the atmospheric pressure in the plain area is between 950 bpa and 1050 bpa.

[0022] Furthermore, the atmospheric pressure of the plateau road is 900bpa.

[0023] Furthermore, the atmospheric pressures in the different plateau environments are 600 bpa, 700 bpa and 800 bpa.

[0024] The patent of this invention proposes a control method for a large-displacement supercharged engine with air port injection that can accurately calculate the fuel injection amount while taking into account the plateau environment. On the one hand, it can reduce the fuel economy at high altitudes while ensuring high power output in the plateau environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 It is the flow chart for oil circuit calibration;

[0027] Figure 2 This is a simplified diagram of oil circuit pressure correction;

[0028] Figure 3 is the calibration coefficient chart; DETAILED DESCRIPTION

[0029] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0031] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0033] The present invention is based on a large amount of road test data, including measurements at different ambient temperatures and altitudes. Through big data statistical cluster analysis, it is found that the key factor affecting the accurate calculation of the oil volume of the airway injection engine is the pressure difference between the oil rail pressure and the intake manifold.

[0034] According to actual data and theoretical analysis, the calculation formula of the required injection amount rk during the actual operation of the engine is as follows: Rk = (rl / a)*f1*f2;

[0035] Where rl is the actual intake flow rate, which is generally measured directly by an air flow meter or calculated from a model value. a is the actual air-fuel ratio. The equivalent air-fuel ratio in the non-exhaust temperature protection stage is 14.7. f1 is the flow correction function of the rail pressure to the fuel injection amount (f1=f(poil), poil is the rail pressure). If it is a port injection engine, f1=1. f2 is the pressure difference correction for fuel injection, which mainly considers the correction of the flow rate by the pressure difference at the front and rear ends of the injector. f2=f(AB) (A represents the intake manifold pressure, and B represents the rail pressure). This patent is a pressure correction control method for the above-mentioned f2 injection amount obtained with the support of big data. The process of oil circuit calibration is as follows: Figure 1 shown.

[0036] A correction control method for calculating the fuel injection amount of a port injection engine at different altitudes comprises the following steps:

[0037] Step 1: Fix the test vehicle on the rotating hub for calibration in a plain area;

[0038] Step 1.1 Set the hub to speed mode, calibrate the engine control to open loop, adjust the initial engine speed, and start data collection when the engine water temperature reaches at least the specified temperature;

[0039] Step 1.2: gradually increase the opening of the engine throttle valve by 5% in steps. As the throttle valve opening increases, the intake manifold pressure also increases. When the intake manifold pressure reaches the initial specified value, the correction coefficient a1 of the operating point is corrected to make the open-loop air-fuel ratio equal to 1. After stabilization for 30 seconds, the a1 value is determined to be locked.

[0040] Step 1.3: Increase the intake manifold pressure to a fixed value for multiple times. Each time the intake manifold pressure is increased to a fixed value, step 1.2 is repeated until the calibration of a2 to a9 is completed.

[0041] Step 1.4 increases the engine speed to a fixed value for multiple times. Each time the engine speed is increased to a fixed value, steps 1.2 and 1.3 are repeated. This process is to verify the calibration result measured at the initial engine speed. If the calibration result measured varies with the calibration result measured at the initial engine speed by more than 5%, the average value a[i] of the calibration result measured at the initial engine speed and the calibration result measured by adjusting the engine speed for multiple times is taken, and a[i] includes a(1) to a(9);

[0042] Step 1.5 After completing the scanning of the above steps, solidify the calibration data and perform calibration verification on the second test vehicle. If the open-loop air-fuel ratio of the two test vehicles can be controlled within the standard range, it is considered that the basic calibration is completed;

[0043] Step 2: Calibrate on plateau roads. To ensure that the calibration data can cover high altitude areas, the correction coefficient for plateau areas needs to be calibrated.

[0044] Step 2.1 Select a long straight section on the plateau road, and start data collection when the engine water temperature reaches at least the specified temperature. Repeat steps 1.2 to 1.3, and the calibration data are recorded as b1 to b9;

[0045] Step 2.2 performs calibration in different plateau environments, repeating step 2.1, and the calibration data are recorded as c1 to c9, d1 to d9, and e1 to e9;

[0046] Step 3: Fill the calibration coefficients into the calibration coefficient table and write the table into the engine control unit ECU.

[0047] The initial engine speed is 2000 rpm.

[0048] The initial prescribed value of the intake manifold pressure is 400 bpa.

[0049] The specific values ​​of increasing the intake manifold pressure to a fixed value multiple times are 500bpa, 600bpa, 700bpa, 800bpa, 900bpa, 1000bpa, 1200bpa and 1400bpa.

[0050] The specific values ​​of increasing the engine speed to a fixed value multiple times are 2500 rpm, 3000 rpm, 4000 rpm and 5000 rpm.

[0051] The standard range is 0.95 to 1.05.

[0052] The engine water temperature is set to 80 degrees.

[0053] The atmospheric pressure in the plain area is between 950bpa and 1050bpa.

[0054] The atmospheric pressure on the plateau road is 900bpa.

[0055] The atmospheric pressures of the different plateau environments are 600 bpa, 700 bpa and 800 bpa.

[0056] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A correction control method for calculating the fuel injection amount of a port injection engine at different altitudes, characterized in that: The following steps are involved: Step 1: Fix the test vehicle on the rotating hub for calibration in a plain area; Step 1.1 Set the hub to speed mode, calibrate the engine control to open loop, adjust the initial engine speed, and start data collection when the engine water temperature reaches at least the specified temperature; Step 1.2: gradually increase the opening of the engine throttle. As the throttle opening increases, the intake manifold pressure also increases. When the intake manifold pressure reaches the initial specified value, the correction coefficient a1 of the operating point is corrected to make the open-loop air-fuel ratio equal to 1. After a period of stability, the a1 value is determined to be locked. Step 1.3: Increase the intake manifold pressure to a fixed value for multiple times. Each time the intake manifold pressure is increased to a fixed value, repeat step 1.2 until the calibration of a2 to a9 is completed. Step 1.4: Increase the engine speed to a fixed value for multiple times. Each time the engine speed is increased to a fixed value, repeat the steps 1.2 and 1.

3. If the calibration result measured varies by more than 5% from the calibration result measured at the initial engine speed, the average value a[i] of the calibration result measured at the initial engine speed and the calibration result measured by adjusting the engine speed for multiple times is taken. Step 1.5 After completing the scanning of the above steps, solidify the calibration data and perform calibration verification on the second test vehicle. If the open-loop air-fuel ratio of the two test vehicles can be controlled within the standard range, it is considered that the basic calibration is completed; Step 2: Calibrate on plateau roads; Step 2.1 Select a long straight section on the plateau road, and start data collection when the engine water temperature reaches at least the specified temperature. Repeat steps 1.2 to 1.3, and the calibration data are recorded as b1 to b9; Step 2.2 performs calibration in different plateau environments, repeating step 2.1, and the calibration data are recorded as c1 to c9, d1 to d9, and e1 to e9; Step 3: Fill the calibration coefficients into the calibration coefficient table and write the table into the engine control unit ECU.

2. The method according to claim 1, characterized in that The initial engine speed is 2000 rpm.

3. The method according to claim 1, characterized in that The initial prescribed value of the intake manifold pressure is 400 bpa.

4. The method according to claim 1, characterized in that: The specific values ​​of increasing the intake manifold pressure to a fixed value multiple times are 500bpa, 600bpa, 700bpa, 800bpa, 900bpa, 1000bpa, 1200bpa and 1400bpa.

5. The method according to claim 1, characterized in that: The specific values ​​of increasing the engine speed to a fixed value multiple times are 2500 rpm, 3000 rpm, 4000 rpm and 5000 rpm.

6. The method according to claim 1, characterized in that The standard range is 0.95 to 1.

05.

7. The method according to claim 1, characterized in that The engine water temperature is set to 80 degrees.

8. The method according to claim 1, characterized in that: The atmospheric pressure in the plain area is between 950bpa and 1050bpa.

9. The method according to claim 1, characterized in that: The atmospheric pressure on the plateau road is 900bpa.

10. The method according to claim 1, characterized in that The atmospheric pressures of the different plateau environments are 600 bpa, 700 bpa and 800 bpa.

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