JPH08121139A - Active noise control device for automobile - Google Patents

Abstract

PURPOSE: To reduce the intake pulsation noise of an engine by beans of a system low in cost by arranging a control means which outputs a sound wave generation control signal retrieved by a sound wave generation control signal retrieval means to a sound wave generation means. CONSTITUTION: An engine 1 allows air to be sucked in through components such as an air cleaner 2, an air intake duct 3, a throttle chamber 4, an intake air collector 5, and an intake manifold 6. A control unit 9 functions as an active noise control unit for reducing intake noise followed by the intake pulsation of the engine 1. In order to actively control noise, a speaker 15 which separately generates sound waves to interfere with intake pulsation (intake noise), is provided in an intake passage in the vicinity of the air cleaner 2. The control unit 9 is provided with an operation processing function outputting a control signal to the speaker 15. By this constitution, the intake noise of the engine can be lowered by means of a system low in cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active noise control system for an automobile, and more particularly to a system for actively reducing noise generated in an intake system of an engine by interference of sound waves separately generated.

[0002]

2. Description of the Related Art In recent years, a technique called active noise control has been proposed as a technique for ensuring the quietness of an automobile. In view of the fact that the sound is a kind of wave phenomenon in which a change in the density of air propagates in the air, the active noise control is based on, for example, noise (primary sound) in a vehicle and another sound wave (two The primary sound is canceled by interfering with the secondary sound).

[0003]

By the way, in the conventional active noise control for automobiles, a sound is generally detected in a vehicle compartment by a microphone, and a noise component to be reduced is extracted from the detected sound, The extracted component is subjected to phase processing to drive the speaker, and complicated filter processing and phase processing must be performed at high speed in order to obtain a sufficient noise reduction effect. An expensive system using (DSP) or the like has been used.

On the other hand, as noise in an automobile, there is noise generated by the intake pulsation of the engine, and even in the active noise control targeting only the noise associated with the intake pulsation, the above expensive system is used. The problem was that the cost would be high. The present invention has been made in view of the above problems, and an object of the present invention is to provide an active noise control device for an automobile, which can effectively reduce noise associated with intake air pulsation of an engine by a low-cost system.

[0005]

Therefore, an active noise control system for an automobile according to the invention of claim 1 is constructed as shown in FIG. In FIG. 1, the intake air flow rate detecting means is means for outputting a detection signal corresponding to the intake air flow rate of the engine.

The sound wave generation control signal search means creates a preset map based on at least one of the amplitude and output signal data of the output signal waveform of the intake air flow rate detection means and the cycle data of the waveform. Reference is made to search for a sound wave generation control signal for generating another sound wave that interferes with inspiratory pulsation. Then, the sound wave generation control means outputs the sound wave generation control signal searched by the sound wave generation control signal search means to the sound wave generation means provided in the intake passage of the engine.

In the vehicle active noise control system according to the invention of claim 2, the control unit for controlling the engine by reading the output signal from the intake air flow rate detection means, the sound wave generation control signal retrieval means and the sound wave generation control. A function as a means is provided, and the sound wave generation control signal retrieving means operates in the control unit using detection data of an intake air flow rate for engine control.

In the vehicle active noise control device according to the invention of claim 3, in the sound wave generation control signal searching means, the amplitude and cycle of the output signal waveform of the intake air flow rate detecting means are detected by the peak detection of the output signal waveform. The calculation is performed based on

[0009]

According to the active noise control system for an automobile of the present invention, since the intake air flow rate detecting means outputs a signal corresponding to the intake air flow rate, a signal having a waveform corresponding to the pulsation when the intake pulsation occurs. Is output. Here, the noise associated with the intake pulsation is reduced by generating another sound wave that interferes with the intake pulsation, but a control signal given to the sound wave generating means for generating such a sound wave, that is, the amplitude of the generated sound wave and The control signal for determining the cycle (frequency) is determined by referring to a map based on the amplitude and cycle of the intake pulsation detected by the intake air flow rate detecting means.

Since the amplitude of the intake pulsation changes according to the intake air flow rate, the intake air flow rate may be used instead of the amplitude. According to the vehicle active noise control device of the invention of claim 2, the active noise control performed using the detection result of the intake air flow rate is not processed by a single unit, but the detection result of the intake air flow rate is also obtained. In the control unit for engine control using, the arithmetic processing for active noise control is performed, and at this time, the data of the intake air flow rate stored in the unit for engine control is diverted.

According to the active noise control system for an automobile of the third aspect of the invention, the peak of the output signal waveform of the intake air flow rate detecting means is detected to determine the cycle as the peak generation interval and the maximum peak value. Amplitude is calculated as the difference from the minimum peak value.

[0012]

Embodiments of the present invention will be described below. Figure 2
1 shows a system configuration of an engine mounted on an automobile in an embodiment, in which air is sucked into an engine 1 through an air cleaner 2, an intake duct 3, a throttle chamber 4, an intake collector 5, and an intake manifold 6.

The throttle chamber 4 is provided with a throttle valve 7 interlocking with an accelerator pedal (not shown) to adjust the intake air amount of the engine 1. An electromagnetic fuel injection valve 8 is provided for each cylinder in a branch portion of the intake manifold 6, and fuel injected from a fuel pump (not shown) and controlled to a predetermined pressure by a pressure regulator is injected into the intake manifold 6. Supply.

The fuel injection valve 8 is intermittently driven to open according to an injection pulse signal sent from a control unit 9 containing a microcomputer, and according to the pulse width of the injection pulse signal calculated by the control unit 9. The fuel injection amount is controlled. Intake duct 3 upstream of the throttle chamber 4
An air flow meter 10 (intake air flow rate detecting means) for detecting the intake air flow rate Q of the engine 1 is provided in the engine.

Here, the air flow meter 10 detects the intake air flow rate Q of the engine as a mass flow rate based on a change in the resistance value of the heat-sensitive resistance arranged in the intake duct, for example, and intake pulsation occurs. Then, the output changes according to the intake pulsation. Further, a crank angle sensor 11 for extracting a rotation signal of the engine 1 from a crank shaft or a cam shaft is provided, and the engine rotation speed Ne is determined based on a detection signal output from the crank angle sensor 11 at every predetermined crank angle. It can be calculated.

Further, the throttle sensor 12 for detecting the opening TVO of the throttle valve 7, the engine cooling water temperature T
A water temperature sensor 13 for detecting w is provided. The control unit 9 calculates the basic injection pulse width Tp based on the engine rotational speed Ne calculated based on the intake air flow rate Q detected by the air flow meter 10 and the detection signal from the crank angle sensor 11, and The final injection pulse width Ti is set by correcting the basic injection pulse width Tp according to the operating conditions such as the cooling water temperature Tw, and the injection pulse signal of the injection pulse width Ti is output to the fuel injection valve 8.

Here, the control unit 9 is
As described above, it functions not only as a fuel injection control unit for the engine but also as an active noise control unit for reducing the noise that propagates into the passenger compartment of the automobile, particularly the intake noise that occurs with the intake pulsation of the engine 1. . In the present embodiment, for active noise control, a speaker 15 (sound wave generating means) for separately generating a sound wave for interfering with intake pulsation (intake noise) is provided in the intake passage near the air cleaner 2. The control unit 9 includes the air flow meter 10
The calculation processing function (function as a sound wave generation control signal searching means and a sound wave generation control means) for outputting a control signal to the speaker 15 to generate a sound wave interfering with the intake pulsation based on the detection signal of It is equipped.

Since the output of the air flow meter 10 is taken into the control unit 9 for controlling the fuel injection amount in the engine as described above, in the active noise control, the engine control As a result, the signal of the intake air flow rate taken into the unit 9 is diverted to control the generation of sound waves. With this configuration, the memory capacity for signal processing can be saved and the processing speed can be improved.

Next, the manner of active noise control (sound wave generation control signal searching means and sound wave generation control means) performed by the control unit 9 will be described with reference to the flowchart of FIG. In the flowchart of FIG. 3, first, in step 1 (denoted as S1 in the figure; the same applies hereinafter), the intake air flow rate detection signal Q from the air flow meter 10 is A / D converted and read. However, such A
The / D conversion value is stored in a signal processing memory common to the engine control, and the data stored in the same memory is used for both the injection amount control and the active noise control.

In step 2, the peaks (maximum peak and minimum peak) of the waveform of the detection signal Q are detected. Then, in step 3, the amplitude Q _pp of the intake pulsation is obtained as the difference between the maximum peak value and the minimum peak value (see FIG. 4). Further, in step 4, the period T of intake pulsation is obtained based on the peak detection interval (see FIG. 4).

In step 5, the period T is converted into the frequency f. In step 6, a speaker control signal (sound wave generation control signal) corresponding to the amplitude Q _pp and the frequency f in advance.
By referring to the stored map, the characteristics of the control signal to be output to the speaker 15 (frequency, amplitude, etc.) are determined, and the determined control signal is output to the speaker 15 in a predetermined phase. A sound wave that interferes with the intake pulsation is generated from the speaker 15 to reduce the intake pulsation (intake noise).
Since the amplitude of the intake pulsation changes according to the intake air flow rate Q, the control signal may be determined based on the level of the intake air flow rate Q instead of the amplitude Q _pp .

Here, the control signal output to the speaker 15 may be an analog sine wave corresponding to the amount of electricity supplied to the voice coil of the speaker 15, or may be a frequency corresponding to the frequency f. The pulse signal may be a pulse signal having a duty ratio corresponding to the amplitude Q _{pp. In} the case of the pulse signal, the sound wave having a frequency corresponding to the frequency of the pulse signal is controlled by controlling ON / OFF of energization of the voice coil. Can be generated with a sound pressure determined by the duty.

According to the above configuration, since the fluctuation of the intake air flow rate (intake pulsation) detected by the air flow meter 10 is the data indicating the noise of the intake system almost as it is, complicated filter processing is not required. The map can be used to easily set the characteristics of sound waves to effectively reduce noise, and an expensive system capable of performing high-speed and complicated calculations is not required. Therefore, the intake noise of the engine can be reduced by a low-cost system.

[0024]

As described above, according to the active noise control system for an automobile of the invention of claim 1, the processing for reducing the noise caused by the intake pulsation of the engine is performed.
Since simple calculation can be performed, there is no need to use an expensive system that can perform complicated calculation at high speed, and the cost of the system can be reduced.

According to the active noise control device for a vehicle of the second aspect of the present invention, in the engine control unit, the engine control and the active noise control are performed using the same detection result of the intake air flow rate. The processing system is simplified and the processing speed can be improved. According to the vehicle active noise control system of the third aspect of the present invention, there is an effect that the cycle and amplitude of the intake pulsation can be easily obtained by detecting the peak in the detection signal of the intake air flow rate.

[Brief description of drawings]

FIG. 1 is a basic configuration block diagram of an apparatus according to the invention of claim 1.

FIG. 2 is a system configuration diagram of an engine in the embodiment.

FIG. 3 is a flowchart showing noise control in the embodiment.

FIG. 4 is a time chart showing the detection characteristics of the amplitude and cycle of intake pulsation in the example.

[Explanation of symbols]

 1 Engine 2 Air Cleaner 3 Intake Duct 4 Throttle Chamber 5 Intake Collector 6 Intake Manifold 7 Throttle Valve 9 Control Unit 10 Air Flow Meter 11 Crank Angle Sensor 15 Speaker

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location G10K 11/16

Claims (3)

[Claims] 1. An intake air flow rate detecting means for outputting a detection signal corresponding to an intake air flow rate of an engine; data of at least one of an amplitude and an output signal level of an output signal waveform of the intake air flow rate detecting means; Sound wave generation control signal searching means for searching a sound wave generation control signal for generating another sound wave that interferes with inspiratory pulsation by referring to a preset map based on the waveform cycle data, and the sound wave generation control An active noise control device for a vehicle, comprising: a sound wave generation control means for outputting a sound wave generation control signal searched by the signal search means to a sound wave generation means provided in an intake passage of an engine. 2. A control unit that reads an output signal from the intake air flow rate detecting means and controls an engine is provided with the functions of the sound wave generation control signal searching means and the sound wave generation control means, and the sound wave generation control signal. 2. The active noise control system for a vehicle according to claim 1, wherein the search means operates in the control unit using detection data of an intake air flow rate for engine control. 3. The sound wave generation control signal searching means,
3. The active noise control device for an automobile according to claim 1, wherein the amplitude and the cycle of the output signal waveform of the intake air flow rate detecting means are calculated based on the peak detection of the output signal waveform.