Hybrid Vehicle Engine Output Control for Air Density Compensation
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Solution Overview
Problem
Hybrid vehicles face poor fuel efficiency due to increased throttle opening required to compensate for decreased air density, leading to higher pumping loss and decreased EGR rate, which worsens fuel economy.
Innovation Solution
A control method for hybrid vehicles that detects air density and adjusts the target engine output accordingly, allowing for the implementation or cancellation of air density correction based on the vehicle's operating state to minimize fuel consumption and maintain efficient engine operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the throttle opening is increased to compensate for decreased air density, then the target engine output can be achieved, but the pumping loss increases and fuel efficiency deteriorates
Solution Approach 1:
The patent changes the target engine output parameter based on air density conditions. When air density is low, the system adjusts the target engine output downward instead of maintaining the standard value, thereby avoiding the need to increase throttle opening and the associated pumping losses while still achieving sufficient power generation.
Solution Approach 2:
The patent implements dynamic adjustment of the target engine output based on real-time air density detection. The control system continuously monitors air density and dynamically modifies the target engine output accordingly, allowing the engine to operate at optimal throttle positions under varying atmospheric conditions rather than using a fixed target output.
2Power
If the throttle opening is increased to compensate for decreased air density, then the target engine output can be achieved, but the EGR rate decreases and fuel economy worsens
Solution Approach 1:
The patent modifies the target engine output parameter in response to air density changes. By reducing the target engine output when air density is low, the system maintains appropriate EGR rates and avoids the fuel economy deterioration that would result from increasing throttle opening to compensate for the density decrease.
3Power
If air density correction is always implemented to maintain target engine output, then generated power can be maintained, but fuel consumption increases
Solution Approach 1:
The patent implements conditional air density correction through dynamic monitoring of multiple parameters including air density, vehicle speed, accelerator opening, and battery state of charge. The target engine output is adjusted based on the combination of these parameters, allowing the system to maintain generated power when necessary while avoiding unnecessary fuel consumption during conditions where correction is not beneficial.
Solution Approach 2:
The patent employs feedback control by continuously monitoring the actual operating conditions and comparing them with target values. The air density correction is applied only when the feedback indicates it is necessary to maintain adequate generated power, thereby avoiding unnecessary fuel consumption that would result from always applying the correction.
Data Source
AI summary
A hybrid vehicle control method for a hybrid vehicle is provided for a drive system including an internal combustion engine, a generator that is driven by the internal combustion engine, and a battery that is charged with electric power generated by the generator. A target power generated by the generator is set and the target engine output is calculated for the internal combustion engine according to the target generated power. The air density in the environment in which the vehicle travels is detected. The target engine output is corrected based on the detected air density with respect to the decrease in air density, and the generated power of the generator is made to follow the target generated power. The execution of air density correction is permitted or stopped depending on an operating state of the drive system.