EV Limp-Home Control Device Preventing Unsafe Movement After Charging

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Solution Overview

Problem

Existing control systems for electric and plug-in hybrid vehicles fail to implement an optimal fail-safe process when failures occur, particularly during charging or driving cycles, as they do not consider previous cycle conditions, leading to inappropriate vehicle operation and safety concerns.

Innovation Solution

A control device that includes a failure detection unit and a drive prohibition unit, which prohibits driving when a failure is detected before the start of a driving cycle and the high-voltage battery is being charged externally, ensuring the vehicle is not in a position to collide with others or obstruct traffic.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If limp-home mode driving is permitted when failure is detected during driving cycle, then vehicle can be moved to safe location, but vehicle may collide with other vehicles or obstruct traffic if failure occurs before driving starts

Engineering Contradiction:

Improvevehicle safetyVSAvoidcollision risk and traffic obstruction

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The control device determines the type of cycle executed in the previous session before allowing limp-home mode driving. By checking whether the previous session was a driving cycle or external charging cycle, the system performs preliminary assessment to decide whether driving permission should be granted, preventing collision risks before they occur

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The control device uses feedback from the previous session's cycle type information to adjust the current driving permission decision. The system stores and retrieves information about whether the previous session was driving or charging, and uses this feedback to make intelligent decisions about whether to permit limp-home mode driving in the current session

Inventive Principle:

Principle #23Feedback

2Reliability

If drive control and charging control are performed separately, then malfunction is prevented, but optimal fail-safe process cannot be executed when failure occurs

Engineering Contradiction:

Improvemalfunction preventionVSAvoidfail-safe process optimization

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The control device merges drive control and charging control functions into a single integrated control system. This unified controller can access information from both driving cycles and external charging cycles, enabling it to determine the previous session type and execute optimal fail-safe processes that consider the complete vehicle operational context

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS8660729B2Limp-home mode control device for electric vehicle

Publication Date: 2014.02.25 SUZUKI MOTOR CORP

AI summary

A control device for a vehicle includes a motor configured to drive wheels, a high-voltage battery configured to supply electric power to the motor, and a battery charger configured to charge the high-voltage battery by using a power supply outside the vehicle. The control device further includes a failure detection unit configured to detect a specific failure, and a drive prohibition unit configured to prohibit driving of the vehicle. The drive prohibition unit prohibits the driving of the vehicle when the failure is detected by the failure detection unit in an initial check before start of driving of the vehicle and when the high-voltage battery is charged by using the power source outside the vehicle immediately before the initial check.