Hybrid Powertrain Power Split for Catalyst Temperature and NOx Control
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Solution Overview
Problem
Hybrid vehicles face inefficiencies in fuel economy and emissions due to creep idling, suboptimal catalyst temperature management, and increased NOx emissions when starting the engine, especially in heavy traffic and during catalyst temperature fluctuations.
Innovation Solution
A control system that uses lookahead information and current state data to dynamically adjust the power split between the electric motor and engine, optimizing engine operation based on predicted vehicle speed, catalyst temperature, and stop times to minimize fuel waste and emissions, and to maintain efficient SCR system operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the engine is turned on while the hybrid vehicle is stopped on the road, then the vehicle can be ready to move, but the NOx emissions from the vehicle increase because the catalyst temperature is not yet high enough for efficient SCR system operation
Solution Approach 1:
The control system predicts future traffic conditions and catalyst temperature evolution to determine the optimal engine start time in advance. By performing preliminary analysis of lookahead information (predicted vehicle speed, traffic patterns, catalyst temperature), the system schedules engine startup to coincide with the moment when catalyst temperature reaches the threshold for efficient SCR operation, thereby avoiding premature engine starts that would generate excessive NOx emissions while still ensuring vehicle readiness when needed.
2Object-generated harmful factors
If the engine is kept running to maintain catalyst temperature for efficient SCR operation, then emissions are reduced, but fuel economy deteriorates due to continuous engine operation during periods when electric motor could suffice
Solution Approach 1:
The control system dynamically adjusts the engine operation strategy based on real-time traffic conditions, predicted vehicle speed, and catalyst temperature. Rather than maintaining a fixed engine-on or engine-off state, the system continuously optimizes the power split between engine and electric motor, adjusting engine load and operation mode to maintain catalyst temperature only when necessary for emissions control, thereby improving fuel economy while ensuring emissions compliance when required.
Solution Approach 2:
The system changes operational parameters (engine load, power split ratio, catalyst temperature threshold) based on predicted traffic conditions and vehicle state. By monitoring parameters such as predicted vehicle speed, current catalyst temperature, and battery state of charge, the control system adjusts these parameters dynamically to find the optimal balance between maintaining catalyst temperature for emissions control and minimizing fuel consumption during periods when electric motor operation would suffice.
3Temperature
If the engine operates at higher power to reach preferred catalyst temperature faster, then catalyst temperature increases more quickly, but fuel consumption increases
Solution Approach 1:
The control system performs preliminary analysis of predicted traffic conditions and vehicle operation patterns to determine the optimal strategy for reaching preferred catalyst temperature. By using lookahead information about future vehicle speed and traffic patterns, the system can plan whether to apply higher engine power temporarily to accelerate catalyst warming, or to use a gentler warming approach if traffic conditions suggest the vehicle will be stopped for extended periods, thereby optimizing the balance between reaching target temperature and minimizing fuel consumption.
Data Source
AI summary
Methods and systems for improving fuel economy and reducing emissions of a vehicle with an electric motor, an engine and an energy storage device are disclosed. The methods and systems involve obtaining lookahead information and current state information, wherein the lookahead information includes a predicted vehicle speed, and the current state information includes a current state of charge (SOC) for the energy storage device coupled to the electric motor; and determining, based on the lookahead information and the current state information, a target power split between the energy storage device and the engine.