Hybrid Vehicle Control System for Prompt Engine Starting
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Solution Overview
Problem
Existing hybrid vehicle control systems face challenges in starting the engine promptly during electric vehicle mode, particularly when the battery is almost fully charged, as they restrict input power to prevent engine cranking, leading to inefficient engine starting.
Innovation Solution
A control system that selects between two electric vehicle modes based on acceptable input power to the electric storage unit, inhibiting the first mode if power is below a threshold, ensuring the engine can be cranked in the second mode with lower electricity generation, and transferring power between storage devices if necessary to maintain appropriate input powers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the first electric vehicle mode is selected to generate greater electricity during engine cranking, then the battery charging efficiency is improved, but the engine cannot be started promptly when the battery is almost fully charged
Solution Approach 1:
The system dynamically switches between two electric vehicle modes (EV-low and EV-high) based on real-time battery state of charge levels. When the battery is nearly full, the system transitions from EV-low mode (higher electricity generation) to EV-high mode (lower electricity generation), enabling adaptive control that resolves the contradiction between charging efficiency and engine starting speed.
Solution Approach 2:
The invention changes the operating parameters of the first motor by selecting different gear ratios through the differential mechanism. EV-low mode uses a first predetermined ratio for higher electricity generation, while EV-high mode uses a second predetermined ratio (smaller than the first) for lower electricity generation. This parameter switching allows the system to adapt to battery charge levels and ensure prompt engine starting when needed.
2Reliability
If the acceptable input power to the battery is restricted when the battery is almost fully charged, then the battery safety is improved, but the engine starting capability is degraded
Solution Approach 1:
The invention segments the electric vehicle mode into two distinct sub-modes (EV-low and EV-high) with different gear ratios and electricity generation characteristics. This segmentation allows the system to select the appropriate mode based on battery state, maintaining battery safety by using EV-high mode (lower power input) when the battery is nearly full, while still preserving engine starting capability through the available electricity generation in that mode.
3Productivity
If the first motor cranks the engine while regenerating electricity, then the engine starting function is achieved, but the battery may be damaged when input power exceeds acceptable limits
Solution Approach 1:
The control system continuously monitors the battery's state of charge and acceptable input power levels, using this feedback to determine whether to permit EV-low or EV-high mode selection. When the battery is almost fully charged, the system receives feedback indicating reduced acceptable input power and automatically selects EV-high mode, preventing battery damage while maintaining sufficient electricity generation for engine cranking.
Solution Approach 2:
The system dynamically adjusts the gear ratio of the differential mechanism based on real-time battery conditions. By switching between the first predetermined ratio (EV-low) and second predetermined ratio (EV-high), the system optimizes the balance between electricity generation and battery protection, ensuring engine starting capability is maintained without exceeding battery input power limits.
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
Enables prompt engine starting without damaging the electric storage unit by shifting to a mode with lower electricity generation when input power is insufficient, ensuring efficient operation across varying vehicle speeds and charging states.
Implementation Method 1
a first motor having a generating function
Implementation Method 2
an electric storage unit in which electricity generated by the first motor is accumulated
Data Source
AI summary
A control system for a hybrid vehicle configured to start an engine promptly during propulsion in an electric vehicle mode. Electric power generation resulting from cranking the engine by a first motor is greater in the first electric vehicle mode compared to a second electric vehicle mode. A controller that is configured to determines whether an acceptable input power to an electric storage unit is smaller than a threshold value. If the acceptable input power to the electric storage unit is smaller than the threshold value, selection of the first electric vehicle mode is inhibited.