Front In-Wheel Motor Power Layout With Series Battery-Capacitor

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Solution Overview

Problem

Hybrid drive vehicles face a vicious cycle of increased weight and reduced fuel efficiency due to the need for large capacity batteries and high voltage systems to power motors, leading to higher weight and costs.

Innovation Solution

A vehicle drive device that uses a capacitor in series with a battery to supply voltage to front in-wheel motors, reducing the current required and minimizing weight and cost by shortening the electric power supply path and positioning the capacitor to overlap with wheels and engine, thereby enhancing safety and reducing the need for drive shafts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a large capacity battery and high voltage system are used to power motors, then sufficient driving force and travel distance are achieved, but vehicle weight increases and fuel efficiency reduces

Engineering Contradiction:
Improvedriving forceVSAvoidvehicle weight
Core Design Contradiction:
PowerVSWeight of moving object

Solution Approach 1:

The power supply system is segmented into two distinct components: a battery for sustained energy supply and a capacitor for high-power pulse delivery. This segmentation allows the capacitor to handle peak power demands during acceleration and motor operation, reducing the burden on the battery and enabling a smaller, lighter battery configuration while maintaining sufficient driving force.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The capacitor is pre-charged from the battery during periods of lower power demand to prepare for high-power output requirements. This preliminary energy storage in the capacitor enables rapid power delivery when needed, reducing the need for an oversized battery system and associated heavy insulation infrastructure.

Inventive Principle:
Principle #10Preliminary action

2Power

If high voltage is applied to motors to obtain sufficient driving force, then motor performance improves, but the electrical system requires sufficient insulation increasing weight

Engineering Contradiction:
Improvemotor outputVSAvoidinsulation system weight
Core Design Contradiction:
PowerVSWeight of moving object

Solution Approach 1:

The electrical system is segmented into low-voltage (battery) and high-voltage (capacitor) sections. The capacitor handles high-voltage connections to the motors, minimizing the length of high-voltage wiring and reducing insulation requirements. The battery operates at lower voltage, allowing for lighter insulation on its connection pathways.

Inventive Principle:
Principle #1Segmentation

3Weight of moving object

If the capacitor is positioned to minimize power supply path length, then weight and cost are reduced, but the capacitor may be exposed to mechanical stress from wheel proximity

Engineering Contradiction:
Improveelectrical system weightVSAvoidcapacitor durability
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The capacitor is positioned in the front portion of the vehicle between the left and right wheels, utilizing the spatial gap that naturally exists in this region. This location provides relatively good mechanical protection while keeping the power supply path to the front wheels short. The capacitor's mounting structure is designed to secure it against vibration and mechanical stress from this proximity to the wheels.

Inventive Principle:
Principle #3Local quality

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 solution efficiently drives vehicles using motors without the weight and cost increases associated with high voltage systems, improving fuel efficiency and safety by distributing the capacitor's impact and sharing power between the battery and electric components.

Implementation Method 1

a capacitor (22) connected in series to the battery (18)

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP3753771B1Vehicle drive device
Publication Date: 2024.02.28 MAZDA MOTOR CORP
  • EP3753771B1 patent drawingFigure 1
  • EP3753771B1 patent drawingFigure 2
  • EP3753771B1 patent drawingFigure 3

AI summary

To provide a vehicle drive device capable of efficiently driving a vehicle by using a motor without falling into the vicious cycle between enhancement of driving via the motor and an increase in vehicle weight. The present invention is a vehicle drive device (10) having a motor for driving the wheels of a vehicle and includes a front wheel motor (20) for driving front wheels (2b) of a vehicle (1) and a battery (18) and a capacitor (22) that supply electric power for driving the front wheel motor (20), in which the voltage of the battery (18) and the capacitor (22) connected in series is applied to the front wheel motor (20) and the capacitor (22) is disposed between the left and right front wheels (2b) of the vehicle (1).