A method for calculating variable valve timing phase angle

Abstract

The present invention discloses a method for calculating the phase angle of variable valve timing, comprising the following steps: judging whether the camshaft is interrupted; judging whether it is the second tooth of the camshaft; calculating the edge phase angle of the second tooth of the camshaft; judging whether the crankshaft is interrupted; crankshaft counting; judging whether the Hall is interrupted; Hall step counting; and calculating the step counting phase angle according to the characteristics of the reducer. The above technical solution not only greatly increases the number of samples and improves the calculation accuracy of the variable valve timing phase angle, but also has good real-time performance, is conducive to the realization of the phase closed-loop algorithm, and is more conducive to the stability of the phase.

Description

Technical Field

[0001] The present invention belongs to the technical field of automobile power system control. More specifically, the present invention relates to a method for calculating a variable valve timing phase angle. Background Art

[0002] With the development of science and technology, people have higher requirements for the power performance and low emissions of automobiles. The variable valve timing technology of the present invention uses a dual closed-loop adjustment of phase and speed. By adjusting the phase angle, the opening and closing time of the intake and exhaust valves are adjusted, thereby achieving the effect of improving power performance and increasing fuel sufficiency. However, the key point of the success of this technology is the calculation of the phase angle, which not only requires a high accuracy of the phase angle, but also a high sample size of the phase angle.

[0003] The problems and defects of the prior art are:

[0004] Traditional phase angle calculation relies solely on the edge calculation of the camshaft signal. Since the camshaft signal disc has a small number of teeth, the most common ones are 3-tooth, 4-tooth and 6-tooth signal discs. Even if the phase angle is calculated on both the rising and falling edges, the maximum number of samples of the phase angle for one rotation of the camshaft is 12. However, the phase closed loop requires a high number of samples of the phase angle, so the traditional method of calculating the phase angle by edge does not meet the requirements at all. Summary of the invention

[0005] The invention provides a method for calculating a variable valve timing phase angle, the purpose of which is to increase the number of samples and improve the calculation accuracy.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] The method for calculating the variable valve timing phase angle of the present invention comprises the following steps:

[0008] Step 1. Start;

[0009] Step 2: Initialize the chip and variables;

[0010] Step 3: Determine whether the camshaft is interrupted; if yes, proceed to the next step; if no, proceed to step 6;

[0011] Step 4: Determine whether it is the second tooth of the camshaft; if yes, proceed to the next step; if no, return to step 3;

[0012] Step 5, calculate the edge phase angle of the second tooth of the camshaft; reset the Hall step counter and crankshaft counter;

[0013] Step 6: Determine whether the crankshaft is interrupted; if yes, proceed to the next step; if no, proceed to step 8;

[0014] Step 7, crankshaft counting; then go to step 10;

[0015] Step 8: Determine whether the Hall is interrupted; if yes, proceed to the next step; if no, return to step 3;

[0016] Step 9: Hall step counting; then proceed to the next step;

[0017] Step 10: Calculate the pedometer phase angle according to the characteristics of the reducer; then return to step 3.

[0018] The phase angle calculation method is applied to an electric variable valve timing closed-loop control system, and the control system acquires a crankshaft signal, a camshaft signal and a Hall signal in real time.

[0019] The crankshaft signal is collected by a crankshaft sensor arranged on the crankshaft of the automobile engine.

[0020] The control system comprises a motor, and the Hall signal is collected by a Hall signal sensor arranged on the motor.

[0021] The camshaft signal is collected by a camshaft sensor on the camshaft connected to a reducer; the reducer is connected to the motor main shaft.

[0022] In step 4, when a non-second tooth is identified, its phase angle is: edge phase angle+fa+fb; fa is the number of Hall steps; and fb is the number of crankshafts.

[0023] The fa and fb are calculated based on a control system equipped with an EVVT controller; the EVVT controller is an electric variable valve timing controller.

[0024] The EVVT controller collects crankshaft camshaft signals and Hall signals in real time, calculates the actual motor speed in real time through the Hall signals, and calculates the current actual phase angle through the crankshaft camshaft signals and Hall signals.

[0025] The control system adjusts the intake volume, exhaust volume and valve opening and closing time by adjusting the timing angle of the camshaft.

[0026] The present invention adopts the above technical solution, which not only greatly increases the number of samples and improves the calculation accuracy of the variable valve timing phase angle, but also has good real-time performance, is conducive to the implementation of the phase closed-loop algorithm, and is more conducive to the stability of the phase. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the flow chart of the calculation method of the present invention. DETAILED DESCRIPTION

[0028] The specific implementation modes of the present invention are further explained in detail below by describing the embodiments with reference to the accompanying drawings, so as to help those skilled in the art to have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of the present invention.

[0029] like Figure 1 The flow of the calculation method of the present invention is a calculation method of the variable valve timing phase angle provided by the present invention. The present invention introduces a new phase angle calculation method, which is based on the step counting method of the edge phase angle and is applied to the phase closed-loop feedback control of the closed-loop control system.

[0030] In order to solve the problems existing in the prior art and overcome its defects, and to achieve the invention purpose of increasing the number of samples and improving the accuracy of calculation, the technical solution adopted by the present invention is:

[0031] like Figure 1 As shown, the method for calculating the variable valve timing phase angle of the present invention comprises the following steps:

[0032] Step 1. Start;

[0033] Step 2: Initialize the chip and variables;

[0034] Step 3: Determine whether the camshaft is interrupted; if yes, proceed to the next step; if no, proceed to step 6;

[0035] Step 4: Determine whether it is the second tooth of the camshaft; if yes, proceed to the next step; if no, return to step 3;

[0036] Step 5, calculate the edge phase angle of the second tooth of the camshaft; reset the Hall step counter and crankshaft counter;

[0037] Step 6: Determine whether the crankshaft is interrupted; if yes, proceed to the next step; if no, proceed to step 8;

[0038] Step 7, crankshaft counting; then go to step 10;

[0039] Step 8: Determine whether the Hall is interrupted; if yes, proceed to the next step; if no, return to step 3;

[0040] Step 9: Hall step counting; then proceed to the next step;

[0041] Step 10: Calculate the pedometer phase angle according to the characteristics of the reducer; then return to step 3.

[0042] The calculated results are fed back to the control system to realize closed-loop control of the control system.

[0043] The use of this pedometer method can not only increase the sample size, but also improve the accuracy, and has good real-time performance, which is conducive to the realization of the phase closed-loop algorithm and is more conducive to the stability of the phase.

[0044] The phase angle calculation method is applied to an electric variable valve timing closed-loop control system, and the control system acquires a crankshaft signal, a camshaft signal and a Hall signal in real time.

[0045] The present invention adopts a pedometer method based on edge phase angle to calculate the phase angle, and a single chip microcomputer of the control system captures a crankshaft signal, a camshaft signal and a Hall signal in real time.

[0046] The crankshaft signal is captured and the number of crankshafts is recorded, the Hall signal is captured and the number of Hall steps is recorded, and the camshaft signal is captured and the camshaft teeth are identified and classified.

[0047] It can be seen from this that when the camshaft rotates one circle, the pedometer phase angle will be updated once with the edge phase angle; when it does not reach one circle, the phase angle is calculated using the pedometer method.

[0048] The cycle of phase angle calculation by the pedometer method is determined according to system requirements. The sample size of the phase angle will change with the change of engine speed. When the engine speed is low, taking the crankshaft 60 missing 2 teeth and the camshaft 6 teeth as an example, the sample size of the camshaft can be as high as 120 for one rotation, which is 10 times larger than the sample size of the phase angle calculated by simple edge calculation.

[0049] The crankshaft signal is collected by a crankshaft sensor arranged on the crankshaft of the automobile engine.

[0050] The control system comprises a motor, and the Hall signal is collected by a Hall signal sensor arranged on the motor.

[0051] The camshaft signal is collected by a camshaft sensor on the camshaft connected to a reducer; the reducer is connected to the motor main shaft.

[0052] When the system recognizes the second tooth of the camshaft, the phase angle is equal to the edge phase angle; while calculating the edge phase angle, the crankshaft count and the Hall step counter are cleared;

[0053] In step 4, when a non-second tooth is identified, its phase angle is: edge phase angle+fa+fb; fa is the number of Hall steps; and fb is the number of crankshafts.

[0054] The fa and fb are calculated based on a control system equipped with an EVVT controller; the EVVT controller is an electric variable valve timing controller.

[0055] When a tooth other than the second tooth is identified, the phase angle is: edge phase angle + fa (number of Hall steps) + fb (number of crankshafts). fa and fb are calculated based on the entire EVVT system.

[0056] The EVVT controller collects crankshaft camshaft signals and motor Hall signals in real time, quickly and accurately following the target phase angle. The electric VVT is not limited by the engine speed at all, solving the problems of hydraulic VVT's inability to adjust phase at low speed and low temperature, as well as slow and low-precision phase adjustment.

[0057] The EVVT controller collects crankshaft, camshaft signals and Hall signals in real time, calculates the actual motor speed in real time through the Hall signals, and calculates the current actual phase angle through the crankshaft camshaft signals and Hall signals.

[0058] The control system adjusts the intake volume, exhaust volume and valve opening and closing time by adjusting the timing angle of the camshaft.

[0059] The actual phase feedback from the Hall signal sensor of the motor is compared to form a phase closed loop, and the motor target speed is calculated together with the camshaft speed.

[0060] The present invention is described above by way of example in conjunction with the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A method for calculating a variable valve timing phase angle, characterized in that: The method comprises the following steps: Step 1. Start; Step 2: Initialize the chip and variables; Step 3: Determine whether the camshaft is interrupted; if yes, proceed to the next step; if no, proceed to step 6; Step 4: Determine whether it is the second tooth of the camshaft; if yes, proceed to the next step; if no, return to step 3; Step 5, calculate the edge phase angle of the second tooth of the camshaft; reset the Hall step counter and crankshaft counter; Step 6: Determine whether the crankshaft is interrupted; if yes, proceed to the next step; if no, proceed to step 8; Step 7, crankshaft counting; then go to step 10; Step 8: Determine whether the Hall is interrupted; if yes, proceed to the next step; if no, return to step 3; Step 9: Hall step counting; then proceed to the next step; Step 10: Calculate the pedometer phase angle according to the characteristics of the reducer; then return to step 3.

2. The method for calculating the variable valve timing phase angle according to claim 1, characterized in that: The phase angle calculation method is applied to an electric variable valve timing closed-loop control system, and the control system acquires a crankshaft signal, a camshaft signal and a Hall signal in real time.

3. The method for calculating the variable valve timing phase angle according to claim 2, characterized in that: The crankshaft signal is collected by a crankshaft sensor arranged on the crankshaft of the automobile engine.

4. The method for calculating the variable valve timing phase angle according to claim 2, characterized in that: The control system comprises a motor, and the Hall signal is collected by a Hall signal sensor arranged on the motor.

5. The method for calculating the variable valve timing phase angle according to claim 4, characterized in that: The camshaft signal is collected by a camshaft sensor; the camshaft sensor is arranged on a camshaft connected to a reducer; and the reducer is connected to a main shaft of a motor.

6. The method for calculating the variable valve timing phase angle according to claim 4, characterized in that: In step 4, when a non-second tooth is identified, its phase angle is: edge phase angle+fa+fb; fa is the number of Hall steps; and fb is the number of crankshafts.

7. The method for calculating the variable valve timing phase angle according to claim 6, characterized in that: The fa and fb are calculated based on a control system equipped with an EVVT controller; the EVVT controller is an electric variable valve timing controller.

8. The method for calculating the variable valve timing phase angle according to claim 7, characterized in that: The EVVT controller collects crankshaft camshaft signals and Hall signals in real time, calculates the actual motor speed in real time through the Hall signals, and calculates the current actual phase angle through the crankshaft camshaft signals and Hall signals.

9. The method for calculating the variable valve timing phase angle according to claim 2, characterized in that: The control system adjusts the intake volume, exhaust volume and valve opening and closing time by adjusting the timing angle of the camshaft.

Images