Hybrid Vehicle Catalyst Temperature Control via Torque Boost
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Solution Overview
Problem
In hybrid vehicles, the catalyst temperature decreases during deceleration states, leading to reduced pollutant removal efficiency due to lower exhaust gas production, which degrades the catalyst's performance.
Innovation Solution
A hybrid vehicle system that includes an engine, a motor generator, and a drive control unit that increases engine torque output and regenerates electric power when the vehicle is decelerating, using this torque to warm the catalyst by increasing exhaust gas production and maintaining its temperature above the activation threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the vehicle is in a deceleration state with reduced exhaust gas production, then energy recovery through regenerative braking is improved, but the catalyst temperature decreases leading to reduced pollutant removal efficiency
Solution Approach 1:
The control unit predicts future catalyst temperature based on current state and driving conditions, then takes advance action by adjusting engine torque before the catalyst temperature actually drops below the activation threshold. This predictive approach allows the system to maintain catalyst temperature proactively rather than reactively, ensuring pollutant removal efficiency is preserved during deceleration events.
Solution Approach 2:
The system implements a feedback loop where the control unit continuously monitors catalyst temperature, compares it against the activation threshold, and adjusts engine torque accordingly. When the predicted or actual temperature approaches the threshold during deceleration, the control unit increases engine torque to generate more exhaust heat, thereby maintaining catalyst temperature within the effective activation range while still allowing regenerative braking to occur.
2Reliability
If engine torque is increased during deceleration to maintain catalyst temperature, then pollutant removal efficiency is improved, but energy recovery from regenerative braking is reduced
Solution Approach 1:
Rather than fully engaging the engine to maintain catalyst temperature (which would eliminate regenerative braking benefits), the control unit applies partial action by providing just enough additional torque to keep the catalyst temperature above the activation threshold. This balanced approach allows the system to maintain catalyst performance while still recovering a significant portion of energy through regenerative braking, optimizing the trade-off between the two competing objectives.
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
Prevents catalyst temperature decrease and maintains its efficiency during deceleration states, ensuring effective pollutant removal and preventing battery overcharging by optimizing regenerative torque and engine operation.
Implementation Method 1
a catalyst provided in an exhaust path of the engine... the catalyst removes the pollutants
Implementation Method 2
a motor generator coupled to the engine and capable of regenerating electric power
Implementation Method 3
increase exhaust gas production, which maintains its temperature above the activation threshold
Data Source
AI summary
A hybrid vehicle includes: an engine; a catalyst; a motor generator; and a drive control unit. The catalyst is provided in an exhaust path of the engine. The motor generator is coupled to the engine and capable of regenerating electric power. The drive control unit is configured to increase torque output from the engine and cause the motor generator to regenerate the electric power by using the torque output from the engine in the case where the hybrid vehicle is in a deceleration state and a temperature of the catalyst is lower than a specified catalyst activation temperature.