An engine magnetic crankshaft sensor raw signal processing circuit and method

Abstract

The application discloses a kind of engine magnetoelectric crankshaft sensor original signal processing circuit and signal processing method, comprising: half-wave rectification and filter module, resistance voltage division circuit module, peak voltage detection and output module, variable gain signal amplification module, hysteresis comparison module and single-chip module.The circuit carries out normalization pretreatment to crankshaft sensor signal, avoids the pretreatment mode of clamping circuit used in most crankshaft signal processing chips, does not cause the distortion of crankshaft signal at low engine speed, simultaneously effectively reduces the phase shift of crankshaft signal processing, to improve the accuracy of engine cylinder determination, it is favorable to realize the more accurate fuel injection control of engine controller, improves the stability of engine cylinder determination.

Description

Technical Field

[0001] This invention relates to the field of engines, and in particular to a processing circuit and signal processing method for the raw signal of an engine magnetoelectric crankshaft sensor. Background Technology

[0002] The fuel injection system is a critical component of the engine. To accurately control engine events such as phase tracking (cylinder detection), fuel injection, ignition, and speed measurement under normal, special, and highly interference-prone conditions, the Electronic Control Unit (ECU) must obtain real-time and accurate crankshaft position signals. However, the raw signal from the magnetoelectric crankshaft position sensor is a sinusoidal pulse signal of -70V to 70V. Therefore, this signal needs to be processed to obtain a 0V-3.3V or 0V-5V square wave signal that the ECU can recognize.

[0003] Existing processing methods first preprocess the raw crankshaft sensor signal using a clamping circuit, clamping the sinusoidal signal from -70V to 70V to a range of 0V-3.3V or 0V-5V. Then, a comparator circuit performs analog-to-digital conversion on the clamped signal. This method cannot guarantee that the raw crankshaft signal will not be distorted at low engine speeds, and there will be a certain phase shift during the clamping stage as the engine operates at different speeds. Summary of the Invention

[0004] The purpose of this invention is to overcome the above-mentioned shortcomings and provide a processing circuit and signal processing method for the raw signal of an engine magnetoelectric crankshaft sensor.

[0005] According to a first aspect, the present invention also provides a raw signal processing circuit for an engine magnetoelectric crankshaft sensor, the circuit comprising:

[0006] The half-wave rectification and filtering module performs half-wave rectification on the original signal VF1 from the magneto-electric crankshaft position sensor and filters out the high-frequency interference signal VF2.

[0007] The resistor voltage divider circuit module divides a voltage with a peak voltage range of 20V-70V into a voltage signal VF3 with a peak voltage range of 0.2V-0.7V.

[0008] The peak voltage detection and peak voltage output module detects and outputs the positive peak signal VF4 of the voltage divider signal VF3 of the original signal of the magnetoelectric crankshaft position sensor, which changes voltage value with crankshaft speed;

[0009] The variable gain signal amplification module, based on the variable gain signal amplification circuit, inputs the positive peak signal VF4 of the voltage signal VF3 into the microcontroller module. The gain control signal VF5 output by the microcontroller module controls the variable gain circuit to amplify the voltage signal VF3 in real time, so that the original signal of the magnetoelectric crankshaft position sensor is always kept in the voltage range of 0V-3.3V or 0V-5V without distortion. This module is used to normalize the original signal of the magnetoelectric crankshaft position sensor and output the square wave signal VF6 of the magnetoelectric crankshaft position sensor.

[0010] The hysteresis comparator module uses a hysteresis comparator to perform analog-to-digital conversion on the normalized crankshaft sensor signal VF6, resulting in a crankshaft position sensor square wave signal VF7 that the controller can recognize, which is either 0V-3.3V or 0V-5V.

[0011] The microcontroller module receives the peak voltage and the positive peak signal VF4 from the peak voltage output module, and outputs the gain control signal VF5 to control the amplification gain. At the same time, it receives the square wave signal output by the hysteresis comparator module to determine the cylinder of the engine.

[0012] The input signal of the half-wave rectification and filtering module is the original signal VF1 from the magnetoelectric crankshaft position sensor, and its output signal is the positive half-cycle signal VF2 of VF1. The input signal of the resistor voltage divider circuit module is VF2, and its output signal is the voltage signal VF3 after voltage division of VF2. The input signal of the peak voltage detection and peak voltage output module is the voltage signal VF3, and its output signal is the real-time positive peak signal VF4 of the voltage signal VF3. The input signal of the variable gain signal amplification module is the voltage signal VF3 and the gain control signal VF5 output by the microcontroller module, and its output signal is the normalized signal VF6 from the magnetoelectric crankshaft position sensor. The input signal of the hysteresis comparator module is VF6, and its output signal is the square wave signal VF7 from the crankshaft position sensor. The input signals of the microcontroller module are the positive peak signal VF4 and the square wave signal VF7, and its output signal is the gain control signal VF5.

[0013] According to a second aspect, the present invention also provides a method for processing the raw signal of an engine magnetoelectric crankshaft sensor, the method comprising the following steps:

[0014] (1) Half-wave rectification and filtering, which performs half-wave rectification and filtering on the original signal of the magnetoelectric crankshaft position sensor at engine speeds of 300r / min - 3200r / min;

[0015] (2) Resistor voltage divider: the voltage of 20V-70V is divided by resistor to a voltage of 0.2V-0.7V to ensure that the subsequent peak detection circuit and variable gain circuit are not damaged by high voltage;

[0016] (3) Peak voltage detection and peak voltage output: detect and output the positive peak voltage of the original signal of the magnetoelectric crankshaft sensor that changes in real time with the engine speed;

[0017] (4) Amplify and normalize the signal voltage of the magnetoelectric crankshaft sensor, which changes with the rotational speed in real time;

[0018] (5) Hysteresis comparison: The normalized crankshaft signal is converted from analog to digital and then output.

[0019] The beneficial effects of this invention are:

[0020] This invention performs normalized preprocessing on the crankshaft sensor signal, avoiding the clamping circuit preprocessing method used by most crankshaft signal processing chips. It also prevents crankshaft signal distortion at low engine speeds and effectively reduces the phase offset of crankshaft signal processing, thereby improving the accuracy of engine cylinder identification. This facilitates more precise fuel injection control by the engine controller and improves the stability of engine cylinder identification. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the processing circuit of the present invention.

[0022] Figure 2 The original signal waveform VF1 of a magnetoelectric crankshaft sensor according to an embodiment of the present invention is shown.

[0023] Figure 3a , 3b Figures 3c and 3d show the crankshaft signal VF2 after half-wave rectification, the crankshaft signal VF3 after voltage division, the crankshaft signal VF6 after normalization, and the crankshaft signal VF7 after analog-to-digital conversion, respectively, of the magnetoelectric crankshaft sensor.

[0024] Figure 4 This is the overall circuit schematic diagram of the processing circuit of the present invention.

[0025] Figure 5a , 5b Figures 5c, 5d, and 5e respectively show schematic circuit diagrams of the half-wave rectification and filtering module, the voltage divider circuit, the peak voltage detection and output module, the variable gain signal amplification module, and the hysteresis comparison module. Detailed Implementation

[0026] It should be understood that the scope of protection of this invention is not limited to specific embodiments. The purpose of providing embodiments is to make the disclosure of this invention more thorough and comprehensive.

[0027] Unless otherwise defined, all techniques and terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The use of terms as used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention.

[0028] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0029] Please see Figure 1 and Figure 4 The signal processing circuit of the present invention includes:

[0030] Half-wave rectification and filtering module (such as Figure 5a As shown, the original signal VF1 from the magnetoelectric crankshaft position sensor is half-wave rectified and the high-frequency interference signal VF2 is filtered out.

[0031] Resistor voltage divider circuit module (such as) Figure 5b As shown, a voltage with a peak voltage range of 20V-70V is divided by a resistor into a voltage signal VF3 with a peak voltage range of 0.2V-0.7V;

[0032] Peak voltage detection and peak voltage output module (such as) Figure 5c As shown), the positive peak signal VF4 is the voltage divider signal VF3 of the original signal of the magnetoelectric crankshaft position sensor, which detects and outputs the voltage value as the crankshaft speed changes.

[0033] Variable gain signal amplification module (such as...) Figure 5d As shown), based on the variable gain signal amplification circuit, the positive peak signal VF4 of the voltage signal VF3 is input to the microcontroller module. The gain control signal VF5 output by the microcontroller module controls the variable gain circuit to amplify the voltage signal VF3 in real time, so that the original signal of the magnetoelectric crankshaft position sensor is always kept in the voltage range of 0V-3.3V or 0V-5V without distortion. This is used to normalize the original signal of the magnetoelectric crankshaft position sensor and output the square wave signal VF6 of the magnetoelectric crankshaft position sensor.

[0034] Hysteresis comparison module (e.g.) Figure 5e As shown, the normalized crankshaft sensor signal VF6 is converted from analog to digital using a hysteresis comparator to obtain a crankshaft position sensor square wave signal VF7 that the controller can recognize, which is 0V-3.3V or 0V-5V.

[0035] The microcontroller module receives signals from the peak voltage and peak voltage output module, and outputs a gain control signal VF5 to control the amplification gain. At the same time, it receives the square wave signal output by the hysteresis comparator module to determine the cylinder of the engine.

[0036] The input signal of the half-wave rectification and filtering module is the original signal VF1 from the magnetoelectric crankshaft position sensor, and its output signal is the positive half-cycle signal VF2 of VF1. The input signal of the resistor voltage divider circuit module is VF2, and its output signal is the voltage signal VF3 after voltage division of VF2. The input signal of the peak voltage detection and peak voltage output module is the voltage signal VF3, and its output signal is the real-time positive peak signal VF4 of the voltage signal VF3. The input signal of the variable gain signal amplification module is the voltage signal VF3 and the gain control signal VF5 output by the microcontroller module, and its output signal is the normalized signal VF6 from the magnetoelectric crankshaft position sensor. The input signal of the hysteresis comparator module is VF6, and its output signal is the square wave signal VF7 from the crankshaft position sensor. The input signals of the microcontroller module are the positive peak signals VF4 and VF7, and its output signal is VF5.

[0037] Please see Figure 2 The original signal VF1 from the magnetoelectric crankshaft sensor is the input signal for this processing method. The signal type is, but is not limited to, a sinusoidal signal in which the voltage changes with the crankshaft speed.

[0038] Figure 3a , 3b 3c and 3d respectively show Figure 1 The signal waveforms for each processing stage are shown. (This is achieved through...) Figure 5a The half-wave rectification shown removes the negative half-cycle waveform of the original signal from the magnetoelectric crankshaft, resulting in signal VF2, with the waveform as follows. Figure 3a As shown, in this embodiment, the voltage range of VF2 is 0-70V. (The rest of the text appears to be a typo and can be omitted.) Figure 5b The resistor divider circuit shown divides the VF2 signal to obtain the VF3 signal, as shown in the waveform. Figure 3b As shown, in this embodiment, the peak voltage range of VF3 is 0.2V-0.7V. (The rest of the text appears to be a continuation of the previous sentence and can be omitted.) Figure 5c The peak voltage detection and output module shown obtains the real-time peak value of the VF3 signal and inputs it to the microcontroller for processing. Through... Figure 5d The variable gain signal amplifier circuit shown produces signal VF6, with the waveform as follows: Figure 3c As shown, in this embodiment, VF6 is a normalized crankshaft signal waveform with a peak voltage constant at 3.3V. (The last sentence appears to be incomplete and possibly refers to a different implementation.) Figure 5e The hysteresis comparator circuit shown converts signal VF6 into a square wave signal VF7, which can be used by the microcontroller for cylinder detection. The waveform is as follows: Figure 3d As shown, in this embodiment, VF7 is a high-level square wave signal of 3.3V.

[0039] As an example, the variable gain signal amplification module includes an operational amplifier, which can be an AD306.

[0040] As an example, the microcontroller module used is TC1728.

[0041] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A raw signal processing circuit for an engine magnetoelectric crankshaft sensor, characterized in that, include: The half-wave rectification and filtering module performs half-wave rectification on the original signal VF1 from the magneto-electric crankshaft position sensor and filters out the high-frequency interference signal VF2. The resistor voltage divider circuit module divides a voltage with a peak voltage range of 20V-70V into a voltage signal VF3 with a peak voltage range of 0.2V-0.7V. The peak voltage detection and peak voltage output module detects and outputs the positive peak signal VF4 of the voltage divider signal VF3 of the original signal of the magnetoelectric crankshaft position sensor, which changes voltage value with crankshaft speed; The variable gain signal amplification module, based on the variable gain signal amplification circuit, inputs the positive peak signal VF4 of the voltage signal VF3 into the microcontroller module. The gain control signal VF5 output by the microcontroller module controls the variable gain circuit to amplify the voltage signal VF3 in real time, so that the original signal of the magnetoelectric crankshaft position sensor is always kept in the voltage range of 0V-3.3V or 0V-5V without distortion. This module is used to normalize the original signal of the magnetoelectric crankshaft position sensor and output the square wave signal VF6 of the magnetoelectric crankshaft position sensor. The hysteresis comparator module uses a hysteresis comparator to perform analog-to-digital conversion on the normalized crankshaft sensor signal VF6, resulting in a crankshaft position sensor square wave signal VF7 that the controller can recognize, which is either 0V-3.3V or 0V-5V. The microcontroller module receives the peak voltage and the positive peak signal VF4 from the peak voltage output module, and outputs the gain control signal VF5 to control the amplification gain. At the same time, it receives the square wave signal output by the hysteresis comparator module to determine the cylinder of the engine. The input signal of the half-wave rectification and filtering module is the original signal VF1 from the magnetoelectric crankshaft position sensor, and its output signal is the positive half-cycle signal VF2 of VF1. The input signal of the resistor voltage divider circuit module is VF2, and its output signal is the voltage signal VF3 after voltage division of VF2. The input signal of the peak voltage detection and peak voltage output module is the voltage signal VF3, and its output signal is the real-time positive peak signal VF4 of the voltage signal VF3. The input signal of the variable gain signal amplification module is the voltage signal VF3 and the gain control signal VF5 output by the microcontroller module, and its output signal is the normalized signal VF6 from the magnetoelectric crankshaft position sensor. The input signal of the hysteresis comparator module is VF6, and its output signal is the square wave signal VF7 from the crankshaft position sensor. The input signals of the microcontroller module are the positive peak signal VF4 and the square wave signal VF7, and its output signal is the gain control signal VF5.

2. The original signal processing circuit of the engine magnetoelectric crankshaft sensor according to claim 1, characterized in that: The operational amplifier used in the variable gain signal amplification module is AD306.

3. The original signal processing circuit of the engine magnetoelectric crankshaft sensor according to claim 1, characterized in that: The microcontroller module uses the TC1728.

4. A method for processing the raw signal of an engine magnetoelectric crankshaft sensor, characterized in that, Including a raw signal processing circuit for an engine magnetoelectric crankshaft sensor as described in any one of claims 1-3, the method includes the following steps: (1) Half-wave rectification and filtering, which performs half-wave rectification and filtering on the original signal of the magnetoelectric crankshaft position sensor at engine speeds of 300r / min - 3200r / min; (2) Resistor voltage divider: the voltage of 20V-70V is divided by resistor to a voltage of 0.2V-0.7V to ensure that the subsequent peak detection circuit and variable gain circuit are not damaged by high voltage; (3) Peak voltage detection and peak voltage output: detect and output the positive peak voltage of the original signal of the magnetoelectric crankshaft sensor that changes in real time with the engine speed; (4) Amplify and normalize the signal voltage of the magnetoelectric crankshaft sensor, which changes with the rotational speed in real time; (5) Hysteresis comparison: The normalized crankshaft signal is converted from analog to digital and then output.

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