US-12627942-B2 - Virtual engine sound control system and control method thereof

US12627942B2US 12627942 B2US12627942 B2US 12627942B2US-12627942-B2

Abstract

A virtual engine sound generating system and method are provided in which each of speakers outputting a virtual engine sound provides an intended optimal virtual engine sound to a driver by adjusting a time for a virtual engine sound to reach the driver and an amplitude of an engine sound that reaches the driver when the head position of the driver changes from a reference position. The system includes speakers provided in a vehicle to output the virtual engine sound, an engine sound generating unit generating the sound, and a controller calculating a head position of a driver based on state information of the driver's seat, adjusting a delay time at which the virtual engine sound is output and/or an amplification factor for each of the speakers based on the calculated head position, and outputting an adjusted delay time and/or amplification factor to the engine sound generating unit.

Inventors

Jae Young Lee

Assignees

HYUNDAI MOBIS CO., LTD.

Dates

Publication Date: 20260512
Application Date: 20231129
Priority Date: 20221207

Claims (13)

1 . A virtual engine sound generating system comprising: a plurality of speakers provided in a vehicle and configured to output a virtual engine sound; an engine sound generating unit configured to generate a signal to each of the plurality of speakers to control the plurality of speakers to output the virtual engine sound; and a controller configured to calculate a head position of a driver based on state information of a driver's seat in the vehicle, to adjust a delay time at which the virtual engine sound is output and an amplification factor, based on calculating a change in amplitude, for each of the plurality of speakers based on the calculated head position, and to output an adjusted for at least one of the delay time and the amplification factor to the engine sound generating unit, wherein, between calculating the delay time and calculating the change in amplitude, a final delay time is calculated, by the controller, by adding an offset set for each of the plurality of speakers to the calculated delay time.
2 . The virtual engine sound generating system of claim 1 , wherein, when adjusting the delay time, the controller is configured to calculate a delay time for each of the plurality of speakers at which the virtual engine sounds output from the plurality of speakers simultaneously reach the calculated head position, and to adjust each of the plurality of speakers based on the calculated delay time.
3 . The virtual engine sound generating system of claim 2 , wherein the state information of the driver's seat includes at least one of position information of the driver's seat in a front/rear direction, angle information between a backrest of the driver's seat and the seat, a length of the backrest, a length from the backrest to a center of a headrest of the driver's seat, and an angle between the backrest and the headrest.
4 . The virtual engine sound generating system of claim 3 , wherein, when the driver's seat is located at a reference position and when a position at which a center line of the seat in the front/rear direction and a center line of the backrest in an up/down direction meet is (x d , y d , z ref ), the head position (P D ) is calculated through Equation (1) below: P D =( x d ,y d +B sin(π−θ S )+ N sin(θ N −π−θ S ), z ref +z S +B cos(π−θ S )− N sin(θ N −π−θ S )− H ) Equation (1) wherein zs is a movement distance of the seat in the front/rear direction at z ref , θ S is the angle between the seat and the backrest, B is the length of the backrest, N is the length from the backrest to the center of the headrest, θ N is a mounting angle of the backrest and the headrest, and H is a statistical value at which the head is located at the center of the headrest.
5 . The virtual engine sound generating system of claim 4 , wherein the plurality of speakers include at least two or more of a front left speaker FL, a front right speaker FR, a rear left speaker RL, a rear right speaker RR, and a rearmost speaker SW, and the controller is configured to calculate a delay time dx through Equation (2) below: d x = P x ⁢ P D _ - max k P k ⁢ P D _ c Equation ⁢ ( 2 ) wherein x, k∈{FL, FR, RL, RR, SW}, P x P D is the distance between the head position of the driver and each speaker, max k P x ⁢ P D _ is a largest distance among the distances between the head position of the driver and each speaker, and c is a speed of sound waves in air.
6 . The virtual engine sound generating system of claim 5 , wherein the controller is configured to set an offset (OFFSET), which is an additional delay time for the virtual engine sounds to reach in an intended order for each of the plurality of speakers based on the calculated delay time.
7 . The virtual engine sound generating system of claim 5 , wherein the controller is configured to calculate a change in amplitude of the virtual engine sound generated as an arrival distance changes for each of the plurality of speakers when the calculated head position changes, and to adjust an amplification factor of the virtual engine sound for each of the plurality of speakers based on the calculated amplitude change.
8 . The virtual engine sound generating system of claim 7 , wherein the controller is configured to calculate the change in amplitude change U(P D ) through Equation (3) below: U ⁡ ( P D ) = 1 j ⁢ λ ⁢ ∫ U S ⁢ e j ⁢ 2 ⁢ π ⁢ 1 λ ⁢ R R ⁢ d ⁢ s Equation ⁢ ( 3 ) wherein U is a sound pressure, λ is a wavelength, s is surface coordinates of each speaker, and R is a distance from a surface of each speaker to the head position of the driver.
9 . The virtual engine sound generating system of claim 8 , wherein the controller is configured to calculate an amplification factor Gx for each of the plurality of speakers through Equation (4) below: G x = A x ⁢ P x ⁢ P T _ P x ⁢ P D _ Equation ⁢ ( 4 ) wherein x, k∈{FL, FR, RL, RR, SW}, P T is a preset reference head position of the driver, P D is a current head position of the driver, and Ax is the amplification factor for each speaker set at the preset reference head position of the driver.
10 . The virtual engine sound generating system of claim 1 , wherein the engine sound generating unit includes: a synthesizer configured to generate an engine sound frequency in a tone or wavetable manner based on a driving speed of the vehicle; a plurality of amplifiers configured to amplify the engine sound frequencies received from the synthesizer for each of the plurality of speakers under the control of the controller; a plurality of equalizers respectively connected to the plurality of amplifiers and configured to differentially increase the received engine sound frequencies to generate normalized engine sound frequencies having a uniform level; and a plurality of time delay units respectively connected to the plurality of equalizers and configured to delay an output of the received engine sound frequency under the control of the controller and to transfer the engine sound frequency to a connected speaker.
11 . A method of controlling a virtual engine sound, the method comprising: calculating, by a controller, a head position of a driver based on state information of a driver's seat in a vehicle; calculating a delay time for outputting a virtual engine sound from each of a plurality of speakers so that the virtual engine sounds output from the plurality of speakers simultaneously reach the head position of the driver based on the calculated head position; calculating a change in amplitude according to a change in distance between the plurality of speakers and the head position of the driver based on the calculated head position; calculating an amplification factor for each of the plurality of speakers so that the virtual engine sound reaches the head position of the driver with a desired engine sound volume for each of the plurality of speakers based on the calculated change in amplitude; and performing a delay time and engine sound amplification on signals generated by an engine sound generating unit for controlling the virtual engine sound outputted by each of the plurality of speakers based on the delay time and the amplification factor calculated for each of the plurality of speakers, wherein, between calculating the delay time and calculating the change in amplitude, a final delay time is calculated by adding an offset set for each of the plurality of speakers to the calculated delay time.
12 . The method of claim 11 , wherein the state information of the driver's seat includes at least one of position information of the driver's seat in a front/rear direction, angle information between a backrest of the driver's seat and the seat, a length of the backrest, a length from the backrest to a center of a headrest of the driver's seat, and an angle between the backrest and the headrest.
13 . The method of claim 12 , wherein in calculating the change in amplitude, the controller calculates a change in the distance between the plurality of speakers and the head position of the driver by comparing a distance between a preset reference head position of the driver and a current head position of the driver.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2022-0169483, filed on Dec. 7, 2022, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. TECHNICAL FIELD The following disclosure relates to a virtual engine sound generating system and a virtual engine sound controlling method, and in particular, to a virtual engine sound generating system and a virtual engine sound controlling method, in which each of a plurality of speakers outputting a virtual engine sound provides an intended optimal virtual engine sound to a driver by adjusting a time for a virtual engine sound to reach the driver and an amplitude of an engine sound that reaches the driver when the head position of the driver changes from a reference position. BACKGROUND Active sound design (ASD) synthesizes vehicle sounds using sound reinforcement techniques in order to change or improve sound inside and outside a vehicle. Recently, as demand for eco-friendly engines has increased, the efficiency of engine systems has increased, but the auditory satisfaction given to consumers has decreased. In addition, electric and fuel cell vehicles also produce high-pitched sound that general combustion engines do not have. Therefore, in order to satisfy the emotional quality of the engine sound to the consumer, the engine sound is generated or reinforced by an audio output unit by using the ASD. Current electric vehicles have significantly less noise and vibration transmitted to the interior thanks to electric motors that rotate quietly and smoothly. Thus, driving sound of electric vehicles is very small and a process of moving in a vehicle may be considered boring. Therefore, an electric vehicle ASD method has been developed to maximize driving immersion by adding auditory elements to electric vehicles. In this method, output torque of the electric vehicle is received and converted into an engine sound at a specific RPM, and then output to the interior through the audio output unit. At this time, at an initial tuning stage, a virtual engine sound is set based on a reference position of the driver's seat and a reference angle of a backrest angle. However, when the driver moves the seat forward or backward or changes the backrest angle, the head position of the driver changes, and accordingly, an arrival distance and an engine sound volume of an initially set virtual engine sound may change. As a result, the arrival distance and an engine sound volume for each speaker intended at the time of initial tuning change, thereby degrading quality of an engine sound experienced by the driver. Therefore, it is required to develop a virtual engine sound system capable of optimally transmitting a virtual engine sound even when the driver's seat position and backrest angle change. Korean Application Publication No. 10-2019-0044292 is an example of a related prior art document. SUMMARY An exemplary embodiment of the present invention is directed to providing a virtual engine sound generating system and a virtual engine sound controlling method, in which each of a plurality of speakers outputting a virtual engine sound provides an intended optimal virtual engine sound to a driver by adjusting a time for a virtual engine sound to reach the driver and an amplitude of an engine sound that reaches the driver when the head position of the driver changes from a reference position. The present invention has the following features in order to solve the above problems. In one general aspect, a virtual engine sound generating system includes: a plurality of speakers provided in a vehicle to output a virtual engine sound; an engine sound generating unit generating the virtual engine sound; and a controller calculating a head position of a driver based on state information of the driver's seat in the vehicle, adjusting at least one of a delay time at which the virtual engine sound is output and an amplification factor for each of the plurality of speakers based on the calculated head position, and outputting an adjusted one to the engine sound generating unit. When adjusting the delay time, the controller may calculate a delay time for each of the plurality of speakers at which the virtual engine sounds output from the plurality of speakers simultaneously reach the calculated head position, and adjust each of the plurality of speakers based on the calculated delay time. The state information of the driver's seat may include at least one of position information of the driver's seat in a front/rear direction, angle information between a backrest of the driver's seat and the seat, a length of the backrest, a length from the backrest to a center of a headrest of the driver's seat, and an angle between the backrest and the headrest. When the driver's seat is located at a reference position and when a position at which a center line of the seat in