BEV Pseudo Engine Sound Control for Low-Speed Pedestrian Alert

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Battery electric vehicles (BEVs) produce low driving sounds, especially at low speeds, making them less noticeable to surrounding individuals, and existing pseudo engine sound systems do not adequately consider the need to notify others of their approach while providing a realistic driving experience for the driver.

Innovation Solution

A battery electric vehicle system with in-vehicle and outside speakers generates a pseudo engine sound, outputting it only inside the vehicle at high speeds and both inside and outside at low speeds, ensuring the driver feels as if driving an engine vehicle and notifying others of its approach.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If pseudo engine sound is output from the outside speaker at low speeds, then surrounding people are notified of the vehicle's approach, but the pseudo engine sound may become mere noise

Engineering Contradiction:

Improvenotification function to surrounding peopleVSAvoidnoise pollution

Core Design Contradiction:

Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The system dynamically adjusts the output of pseudo engine sound based on vehicle speed. At low speeds (≤ first speed), the pseudo engine sound is output from both in-vehicle and outside speakers to notify surrounding people. At high speeds (> first speed), the pseudo engine sound is output only from the in-vehicle speaker, preventing noise pollution. This dynamic adjustment resolves the contradiction between notification function and noise pollution.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system applies different sound output strategies to different spatial zones. The inside speaker provides pseudo engine sound for the driver's experience, while the outside speaker provides pseudo engine sound only when needed for surrounding people's notification. This localized quality control ensures the pseudo engine sound serves its notification function without becoming unnecessary noise.

Inventive Principle:

Principle #3Local quality

2Ease of operation

If pseudo engine sound is output from the in-vehicle speaker, then the driver experiences a realistic feeling of driving an engine vehicle, but the surrounding people are not notified of the vehicle's approach

Engineering Contradiction:

Improvedriving experienceVSAvoidlack of notification to surrounding people

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The sound output system is segmented into two independent channels: in-vehicle speaker and outside speaker. The in-vehicle speaker continuously outputs pseudo engine sound to provide realistic driving experience. The outside speaker outputs pseudo engine sound only at low speeds to notify surrounding people. This segmentation allows both functions to operate independently without interference.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The pseudo engine sound system serves multiple functions through different speakers. The in-vehicle speaker provides the driver experience function, while the outside speaker provides the notification function to surrounding people. This multi-functionality resolves the contradiction by ensuring both driving experience and safety notification are achieved.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Productivity

If the battery electric vehicle travels at low speeds, then the vehicle is quiet and energy efficient, but surrounding people cannot notice the presence of the vehicle

Engineering Contradiction:

Improveenergy efficiencyVSAvoidvisibility to surrounding people

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system periodically assesses vehicle speed and adjusts sound output accordingly. At low speeds where energy efficiency is prioritized, the system activates the outside speaker to provide periodic notification sounds to surrounding people. This periodic action ensures safety notification without requiring continuous high-energy sound output.

Inventive Principle:

Principle #19Periodic action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The system provides a realistic driving experience for the driver and effectively notifies surrounding individuals of the vehicle's presence without the pseudo engine sound becoming mere noise, maintaining a natural driving sensation and effective notification.

Implementation Method 1

a speaker including an in-vehicle speaker that outputs a sound to inside of the battery electric vehicle and an outside speaker that outputs a sound to outside of the battery electric vehicle

Methodology Applied

Scientific EffectElectroacoustic conversion:

Data Source

PatentUS12576725B2Battery electric vehicle and vehicle management system

Publication Date: 2026.03.17 TOYOTA JIDOSHA KK

AI summary

A battery electric vehicle includes a speaker including an in-vehicle speaker that outputs a sound to the inside of the vehicle and an outside speaker that outputs sound to the outside of the vehicle. The battery electric vehicle further includes one or more processors configured to generate a pseudo engine sound and output the pseudo engine sound from a speaker mounted on the battery electric vehicle. When a vehicle speed of the battery electric vehicle is higher than a first speed, the one or more processors output the pseudo engine sound from the in-vehicle speaker, but not from the outside speaker. When the vehicle speed of the battery electric vehicle is equal to or lower than the first speed, the one or more processors output the pseudo engine sound from both the in-vehicle speaker and the outside speaker.