Hybrid Vehicle Deceleration Control for Catalyst Heat and Battery SOC
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Solution Overview
Problem
In hybrid vehicles, maintaining the catalyst temperature of the exhaust emission control device while preventing battery overcharge during deceleration, particularly on long downhill slopes, is challenging due to the reliance on regenerative braking which can lead to a drop in catalyst temperature and exceed the battery's state of charge (SOC) limit.
Innovation Solution
A control device that switches between engine resistance enhancement and motor assist operations based on battery SOC levels to maintain catalyst temperature, using engine combustion and regenerative braking cooperatively to manage deceleration without overcharging the battery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If regenerative braking is used during deceleration, then battery charge is increased, but catalyst temperature drops below operating temperature
Solution Approach 1:
The control device changes the operating parameters of the engine by adjusting injection timing and quantity to enable combustion during deceleration, thereby maintaining catalyst temperature while managing battery charge levels through controlled combustion events
2Temperature
If engine combustion is performed to maintain catalyst temperature, then catalyst temperature is maintained, but battery SOC exceeds upper limit
Solution Approach 1:
The control device adjusts engine combustion parameters including injection timing and quantity to optimize the balance between maintaining catalyst temperature and managing battery SOC, performing combustion only when necessary and at controlled intensities
Solution Approach 2:
The control device continuously monitors catalyst temperature and battery SOC levels, using feedback from these sensors to dynamically adjust combustion control strategies, ensuring temperature maintenance while preventing battery overcharge
3Use of energy by moving object
If engine braking is enhanced to prevent battery overcharge, then deceleration is increased, but drivability and comfort are reduced
Solution Approach 1:
The control device modifies engine resistance parameters dynamically based on vehicle operating conditions, adjusting the degree of engine braking to provide sufficient deceleration while maintaining driver comfort and drivability through smooth torque management
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
Maintains catalyst temperature effectively while preventing battery overcharge, ensuring drivability and comfort during deceleration by offsetting engine braking losses with motor torque, thus avoiding discomfort to the vehicle driver.
Implementation Method 1
An exhaust system of the engine is provided with a catalytic converter which neutralizes exhaust gas
Implementation Method 2
For diesel engines, an exhaust emission control device including an SCR (Selective Catalytic Reduction) catalyst for removing NOx may be used
Implementation Method 3
during deceleration, regenerative braking based on a regenerative resistance of the motor may be used... the power generated by the motor is stored in a battery
Data Source
AI summary
A control device of a vehicle includes a controller. The vehicle includes an engine having an exhaust system including a combustion chamber and a catalyst, a motor able to operate drive wheels of the vehicle, and a battery which supplies driving power to the motor when the motor operates the drive wheels (motor assist operation), and is charged when the motor generates power (regenerative operation). During deceleration, the controller performs one of a first control which increases an engine resistance for a higher deceleration than requested, and performs the motor assist operation according to the engine resistance increase, when a battery state of charge (SOC) is a first given value or above; and a second control which controls a combustion state of the engine to raise a catalyst temperature, and performs the regenerative operation, when the battery SOC is a second given value below the first given value.