Hybrid Vehicle Torque Blending With Lean-Burn Engine Restart
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Solution Overview
Problem
Hybrid vehicles face challenges in efficiently transitioning from a stop state to an optimal operation point, leading to increased nitrogen oxide emissions and inefficient fuel consumption due to frequent mode switching and idle engine operations.
Innovation Solution
A hybrid vehicle system with a controller that synchronizes engine and motor velocities, adjusts the number of combusted cylinders, and modifies air-fuel ratios to gradually increase engine torque while minimizing nitrogen oxide discharge through lean burn combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the engine is operated in theoretical air-fuel ratio mode during torque blending transition, then the engine can quickly reach target torque, but a large amount of nitrogen oxide is generated
Solution Approach 1:
The patent changes the air-fuel ratio parameter from theoretical to lean burn mode during torque blending transition. This parameter change allows the engine to operate in a different combustion regime that reduces nitrogen oxide emissions while still achieving the required torque output through coordinated motor assistance.
Solution Approach 2:
The patent merges the operation of the engine with the electric motor during the transition phase. By combining the torque from the engine (operating in lean burn mode) with the torque from the electric motor, the system achieves the required target torque without relying solely on high-emission theoretical air-fuel ratio combustion.
2Use of energy by moving object
If the engine operates in lean burn combustion mode at maximum thermal efficiency operation point, then fuel efficiency is enhanced, but the engine cannot operate in this mode across all operating areas due to technical constraints
Solution Approach 1:
The electric motor acts as an intermediary that enables the engine to operate in lean burn mode across a wider range of operating conditions. The motor provides supplemental torque when the engine operates in lean burn mode, allowing the system to meet demand requirements while maintaining the fuel-efficient combustion regime.
Solution Approach 2:
The patent dynamically adjusts the operating mode between lean burn and theoretical air-fuel ratio based on real-time conditions. The system transitions between different combustion modes and power source combinations (engine-only, motor-only, or combined) to optimize fuel efficiency while meeting performance requirements across all operating areas.
3Productivity
If the engine is frequently stopped and restarted in hybrid vehicle operation, then the vehicle can operate in EV mode for efficiency, but the engine frequently transitions through high-emission states
Solution Approach 1:
The system performs preliminary synchronization of engine and motor velocities before clutch engagement. This preliminary action allows the engine to be prepped in lean burn mode before the transition begins, reducing the duration and emission intensity of the transition phase when the engine restarts after idle stop.
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
Reduces nitrogen oxide emissions and minimizes fuel consumption by optimizing the transition process, reducing engine vibrations and shocks, and maintaining consistent torque output.
Implementation Method 1
a first motor starting the engine, and selectively operating as a generator to generate electrical energy
Implementation Method 2
a second motor generating power required for driving the hybrid vehicle
Implementation Method 3
an engine including a plurality of cylinders for generating power required for driving the hybrid vehicle by combustion of fuel
Data Source
AI summary
A hybrid vehicle may include: an engine including a plurality of cylinders for generating power required for driving the hybrid vehicle by combustion of fuel; a first motor starting the engine and selectively operating as a generator to generate electrical energy; a second motor generating power required for driving the hybrid vehicle; a clutch provided between the engine and the second motor; and a controller configured for synchronizing a velocity of the second motor and an engine velocity and for coupling the clutch, in a transition section in which the engine moves from a stop state to an optimal operation point area as an operation area of the engine, and gradually decreasing a torque of the second motor and gradually adjusting the number of combusted cylinders among the plurality of combustion chambers to gradually increase the engine torque.