Hybrid Vehicle Engine Output Control for System Efficiency

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Solution Overview

Problem

Hybrid vehicles face inefficiencies in system performance and fuel mileage due to suboptimal engine power management, which prioritizes battery charge state over overall system efficiency, leading to decreased fuel efficiency and inadequate heat generation during low-load operations.

Innovation Solution

A control apparatus that determines engine output based on a system efficiency function incorporating drive power, generated electric power, discharged electric power, and heat, ensuring operation at optimal efficiency points to maximize system efficiency and improve fuel mileage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the engine power is determined solely based on battery charge state to maintain SOC within preset range, then the battery charge state is maintained, but the system efficiency deteriorates and fuel mileage cannot be effectively improved

Engineering Contradiction:

Improvebattery charge state maintenanceVSAvoidsystem efficiency

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent changes the control parameter from simple battery SOC maintenance to a comprehensive system efficiency function that considers multiple parameters including drive power, generated electric power, discharged electric power, and heat amount. This allows the engine output to be optimized for overall system efficiency rather than just battery charge state.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The engine output determination is made multi-functional by simultaneously considering battery charge maintenance, system efficiency optimization, and heat amount assurance. The control apparatus integrates multiple objectives into a single unified control strategy that balances electrical energy management with thermal energy requirements.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Speed

If the amount of electricity generation during high driving load is set to high level for quick recovery of battery SOC, then the battery SOC recovers quickly, but the system efficiency deteriorates

Engineering Contradiction:

Improvebattery SOC recovery speedVSAvoidsystem efficiency

Core Design Contradiction:

SpeedVSUse of energy by moving object

Solution Approach 1:

The patent implements dynamic adjustment of electricity generation amount based on real-time system conditions. Rather than using a fixed high generation level, the control apparatus dynamically optimizes the generation amount according to the system efficiency function, which varies with drive power, battery state, and thermal requirements.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The control strategy changes from prioritizing rapid SOC recovery to optimizing the balance between SOC recovery and system efficiency. The engine output is adjusted based on the comprehensive efficiency function that prevents excessive electricity generation that would waste energy.

Inventive Principle:

Principle #35Parameter changes

3Temperature

If the engine operation frequency is increased to generate sufficient heat in winter, then the heat amount is sufficient, but the fuel consumption increases

Engineering Contradiction:

Improveheat amountVSAvoidfuel consumption

Core Design Contradiction:

TemperatureVSUse of energy by moving object

Solution Approach 1:

The engine output determination simultaneously serves dual purposes: generating electrical energy and producing thermal energy. The system efficiency function integrates both electrical output requirements and heat amount requirements, allowing the engine to fulfill both functions optimally rather than requiring separate control strategies.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent extends the control parameters to include heat amount alongside electrical energy parameters. This comprehensive parameter set allows the system to optimize engine operation for combined electro-thermal output, ensuring sufficient heat generation during winter while minimizing fuel consumption through efficient operating points.

Inventive Principle:

Principle #35Parameter changes

4Use of energy by moving object

If the EV drive is used for too long to reduce fuel consumption, then fuel mileage improves, but the battery SOC lowers excessively and the EV drive must be interrupted

Engineering Contradiction:

Improvefuel mileageVSAvoidbattery SOC level

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The control apparatus performs preliminary assessment of battery SOC trends and proactively adjusts engine output to prevent excessive SOC depletion. Rather than waiting for SOC to drop to critical levels, the system anticipates the need for charge and schedules engine operation to maintain SOC within optimal ranges, ensuring continuous EV drive capability.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS9067596B2Control apparatus of hybrid vehicle

Publication Date: 2015.06.30 DENSO CORP

AI summary

A control apparatus of a hybrid vehicle has an engine, a motor, an engine-driven generator, and a battery. A controller determines an engine output based on an efficiency function that is defined by a drive power of the vehicle, a generated electric power from the generator, and a discharged electric power from the battery. The determined engine output controls the efficiency function to be kept in a value range that includes a maximum efficiency value of the efficiency function.