Variable Engine Idle Speed for Sail Mode Power
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional vehicles with internal-combustion engines face electric power shortfalls during 'sail mode' due to reduced rotational engine speed, leading to increased battery wear and charge imbalance, as electric power generation is dependent on engine speed.
Innovation Solution
A method to control the internal-combustion engine's rotational speed during decoupling from the drive wheels, setting a variable desired idling speed based on generator characteristics, temperature, and current generation to ensure sufficient electric power, using a control unit to manage decoupling and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the internal-combustion engine is decoupled from the drive wheels to enable coasting in sail mode, then fuel consumption is reduced and drag torques are minimized, but electric power generation decreases leading to power shortfalls and increased battery wear
Solution Approach 1:
The patent applies dynamics by making the idling speed of the internal-combustion engine variable rather than fixed. The control unit dynamically adjusts the idling speed within a range (e.g., 600-1200 rpm) based on real-time conditions including generator power output requirements, battery charge state, and vehicle operating conditions. This dynamic adjustment allows the system to maintain sufficient electric power generation during sail mode while minimizing fuel consumption, resolving the contradiction between energy loss reduction and power supply reliability.
2Productivity
If the rotational engine speed is reduced to idle speed during decoupling, then drag torques are reduced for fuel savings, but the generator produces insufficient current leading to charge balance deterioration
Solution Approach 1:
The patent applies parameter changes by modifying the engine's rotational speed parameter from a fixed idle speed to a variable speed range. The control unit changes the target rotational speed based on the required generator power output, battery charge state, and other operating parameters. This allows the engine to rotate faster than traditional idle speeds when sufficient electric power is needed, thereby increasing generator current output while still maintaining fuel efficiency benefits compared to full-power operation.
3Ease of operation
If the internal-combustion engine is decoupled during coasting phases, then vehicle coasting performance is improved, but battery wear increases due to power shortfalls
Solution Approach 1:
The patent applies feedback by implementing a control unit that continuously monitors battery charge state, generator power output, engine rotational speed, and other parameters. Based on this feedback, the control unit adjusts the engine's idling speed in real-time to ensure sufficient electric power generation. This feedback mechanism prevents battery discharge into deep discharge zones that cause excessive wear, while still allowing coasting operation to proceed, thus resolving the contradiction between coasting performance and battery protection.
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
Prevents electric power shortfalls by maintaining optimal rotational speed, reducing battery wear, and ensuring consistent electric power availability without compromising comfort or battery quality.
Implementation Method 1
the electric energy generation, in the case of conventional motor vehicles having an internal-combustion engine, takes place predominantly by belt-driven generators
Data Source
AI summary
A method is provided for operating a powertrain in a motor vehicle, the powertrain having an internal combustion engine and components for coupling the internal combustion engine to the drive wheels of the motor vehicle in a controllable manner. The internal combustion engine is decoupled from the drive wheels if specified operating conditions are present while the motor vehicle is traveling in order to allow the vehicle to coast. Further, a rotational engine speed is set to a specified target idle speed. The target idle speed is specified in a variable manner depending on the situation.