Hybrid Vehicle Control Device Engine Speed Stability
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Solution Overview
Problem
Conventional vehicle control devices experience engine speed fluctuations when the air conditioner is operated, as the torque required for air conditioning is added to the power source output, leading to increased engine speed and rotation variability.
Innovation Solution
A control method that calculates a target driving force for the drive wheel, subtracts the electric power consumption of the air conditioner from this force, and adjusts the engine output accordingly to maintain a stable operation point, thereby minimizing engine speed fluctuations during air conditioner operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the torque required for air conditioner operation is added to the power source output, then the air conditioner can operate, but the engine speed becomes high and fluctuates
Solution Approach 1:
Instead of adding air conditioner torque to the power source output (conventional approach), the invention subtracts the driving force corresponding to air conditioner power consumption from the target driving force. This inverted calculation approach prevents engine speed increase and maintains stability while still enabling air conditioner operation through the motor's power generation capability.
Solution Approach 2:
The invention changes the calculation parameters for target driving force by subtracting the air conditioner's power consumption equivalent driving force. This parameter modification allows the system to account for air conditioner energy needs without translating them into additional engine torque requirements, thereby maintaining engine speed stability.
2Power
If the target output is raised to include air conditioner torque, then the air conditioner receives sufficient power, but the equal output line shifts and engine rotation increases
Solution Approach 1:
The invention inverts the conventional power calculation by subtracting air conditioner power consumption from the target driving force rather than adding it to the power source output. This ensures the air conditioner receives adequate power through the motor's generation capability while preventing engine rotation speed increase.
Solution Approach 2:
The invention replaces the mechanical approach of directly coupling air conditioner torque to the engine output with an electrical/electronic calculation approach. By using power consumption data and converting it to equivalent driving force for subtraction from target driving force, the system determines air conditioner power needs without mechanically increasing engine load and rotation speed.
3Device complexity
If conventional control methods are used, then the system is simple, but engine speed fluctuates during air conditioner operation
Solution Approach 1:
The invention incorporates feedback by continuously monitoring air conditioner operation status and adjusting the target driving force calculation accordingly. When the air conditioner is ON, the system subtracts the corresponding driving force from the target driving force; when OFF, no subtraction is performed. This feedback mechanism maintains engine speed stability without requiring complex additional hardware.
Data Source
AI summary
A control device for a hybrid vehicle having an engine, a motor which drives by power of a battery, and an air conditioner which operates by power of the battery, includes a target driving force calculator configured to calculate a target value of driving three transmitted to a drive wheel from a driving source as target driving force, an air conditioner manager configured to manage an ON/OFF state of an air conditioner, and a controller configured to calculate a request output by adding the target driving force to a system output requested to the drive source by a system request, calculate an operation point of the engine for optimally driving the engine in response to the request output, control the engine to drive at the operation point, and control the motor based on the request output.