Hybrid Engine Power Quantization for Fuel Efficiency
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Solution Overview
Problem
Conventional hybrid electric vehicle engine power control systems experience inefficiencies due to chaotic driver power commands, leading to engine power fluctuations that reduce combustion efficiency and increase fuel consumption, especially during aggressive driving with frequent acceleration and deceleration events.
Innovation Solution
Implementing a controller that requests power from the engine at quantized levels and utilizes the traction battery to smooth out power demands, employing engine power command quantization with hysteresis and filtering processes to mitigate transients and optimize fuel economy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the engine directly responds to any change of the driver power command, then the engine power command can follow driver demand, but the engine power fluctuates causing combustion inefficiency and increased fuel consumption
Solution Approach 1:
The patent segments the engine power command into discrete quantized levels rather than allowing continuous variation. The controller selects from a predefined set of quantized power levels, which reduces high-frequency fluctuations and dithering while maintaining adequate response to driver demand. This segmentation smooths engine operation and reduces transient fuel consumption.
Solution Approach 2:
The patent implements periodic action through hysteresis bands around each quantized power level. When the desired power command enters a hysteresis band associated with a quantized level, the engine power is held at that level until the command exits the band in the opposite direction. This periodic holding action reduces frequent power changes and improves combustion efficiency.
2Speed
If the engine power command fluctuates frequently, then the engine can respond to aggressive driving, but combustion efficiency deteriorates and transient fuel increases
Solution Approach 1:
By dividing the continuous power command range into discrete quantized levels, the system reduces the frequency of power changes while maintaining adequate response capability. The segmentation filters out high-frequency fluctuations that degrade combustion efficiency during aggressive driving maneuvers.
Solution Approach 2:
The patent applies preliminary action through predictive scheduling of engine control parameters based on the quantized power command levels. By anticipating the quantized power levels before actual transitions occur, the system prepares optimal engine settings in advance, maintaining combustion efficiency during transient conditions.
3Manufacturing precision
If engine control parameters are predicatively scheduled based on rate of change of engine power command, then engine settings can be optimized, but power disturbances cause non-optimum settings and worsen fuel/air errors
Solution Approach 1:
The quantization of engine power command into discrete levels provides a stable basis for predictive scheduling of engine control parameters. Each quantized level has associated optimal parameter settings, reducing the complexity and improving accuracy of parameter scheduling compared to continuous power commands.
Solution Approach 2:
The patent implements feedback mechanisms to monitor actual engine operation and adjust control parameters accordingly. The closed-loop feedback system detects deviations from optimal fuel/air ratios caused by power disturbances and corrects them, maintaining accuracy despite transient conditions.
4Loss of energy
If the controller requests power at quantized levels, then the battery can smooth power demands, but the engine operates at discrete power points
Solution Approach 1:
The patent merges the engine and battery into a coordinated hybrid power system. The engine operates at quantized power levels while the battery compensates for the differences between quantized levels and actual power demands. This combination maintains fuel efficiency by keeping the engine at optimal discrete operating points while preserving adaptability through battery power supplementation.
Solution Approach 2:
The battery acts as an intermediary between the quantized engine power output and the continuous power demand. It absorbs or supplies power to bridge the gaps, smoothing the overall power delivery while allowing the engine to operate efficiently at discrete quantized levels without sacrificing system adaptability.
Data Source
AI summary
A vehicle having and engine and traction battery and a method of operating an engine are disclosed. A controller operates the engine according to quantized engine power levels. The quantization level depends upon a total power demand. For low values of total power demand, the selected quantization level may be at least equal to the total power demand. For high values of total power demand, the selected quantization level may be less than or equal to the total power demand. In between low and high values, the selected quantization level may be the quantization level nearest the total power demand. The traction battery may receive or provide power depending on the selected quantization level.