Hybrid Vehicle Front Compartment Layout for PCU Collision Protection

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Solution Overview

Problem

Existing layout structures for hybrid vehicles do not effectively prevent damage to the power control unit (PCU) during collisions, as they primarily focus on protecting the wire harness rather than the PCU itself.

Innovation Solution

The PCU is positioned on the upper surface of the transaxle, with vehicle components such as the air cleaner, reservoir tank, or control unit arranged in front of it, absorbing collision energy and reducing shock through their lower stiffness, thereby protecting the PCU. Additionally, the low-voltage battery is placed on the outer side of the vehicle, ensuring that collision energy is absorbed by these components rather than the PCU.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the wire harness and PCU are connected on the upper surface of the PCU to prevent wire harness damage, then the wire harness is protected from collision damage, but the PCU itself remains vulnerable to collision damage

Engineering Contradiction:

Improvewire harness protectionVSAvoidPCU collision damage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a foam material as an intermediary protective layer between the PCU and the external environment. This foam intermediary absorbs collision energy and prevents direct impact to the PCU, while allowing the wire harness connection on the upper surface to remain intact for wire harness protection.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies cushioning material (foam) around the PCU before collision occurs. This beforehand cushioning creates a protective barrier that absorbs impact energy during head-on collisions or diagonal front collisions, preventing the PCU from suffering direct damage while maintaining the wire harness connection configuration.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Volume of moving object

If the PCU is positioned on the upper surface of the transaxle for compact layout, then space utilization is improved, but the PCU becomes more exposed to collision risks

Engineering Contradiction:

Improvefront compartment space utilizationVSAvoidPCU collision exposure

Core Design Contradiction:

Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent nests the PCU within the transaxle assembly, positioning it on the upper surface of the transaxle. This nesting arrangement optimizes space utilization in the front compartment while the surrounding foam material provides protective cushioning against collision forces.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Object-affected harmful factors

If components with lower stiffness are placed in front of the PCU to absorb collision energy, then the PCU is protected from impact, but the overall structural rigidity of the front compartment may be reduced

Engineering Contradiction:

ImprovePCU impact protectionVSAvoidfront compartment structural rigidity

Core Design Contradiction:

Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent applies local quality by using foam material with lower stiffness specifically in the regions where collision impact is most likely to occur (around the PCU and in front of it), while maintaining higher stiffness in other structural areas. This localized softness provides impact absorption without compromising the overall structural rigidity of the front compartment.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent employs composite material strategy by combining foam material (lower stiffness) for impact absorption with the rigid transaxle and PCU structure (higher stiffness). This composite approach creates a multi-layered protection system where the foam absorbs collision energy while the rigid structures maintain structural integrity and compartment strength.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS10994600B2Layout structure for front compartment of hybrid vehicle

Publication Date: 2021.05.04 TOYOTA JIDOSHA KK

AI summary

A front compartment is provided with an engine, an air cleaner, a radiator, a reservoir tank, a motor unit, an auxiliary battery, and an EFI-ECU. The engine, the reservoir tank, the motor unit and the EFI-ECU are aligned in a vehicle's width direction. The air cleaner and the auxiliary battery are also aligned in the vehicle's width direction. The air cleaner is located in front of the motor unit. The motor unit includes a power control unit and a transaxle. The air cleaner is located in front of the power control unit. The auxiliary battery is located diagonally forward to left of the motor unit.