Mild Hybrid Starter-Generator Engine Speed Control
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Solution Overview
Problem
Mild hybrid vehicles face inefficiencies in engine starting, as conventional methods inject fuel immediately upon cranking, leading to suboptimal fuel consumption and economy.
Innovation Solution
A method where the mild hybrid integrated starter-generator (MHSG) increases the engine's rotation speed before initiating fuel injection, allowing for controlled timing of fuel injection based on monitored status data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If fuel is injected immediately upon cranking, then the engine can start quickly, but fuel consumption increases
Solution Approach 1:
The MHSG performs preliminary action by increasing the engine rotation speed to a predetermined level before fuel injection is initiated. The controller monitors the rotation speed during cranking and delays fuel injection until the speed threshold is met, ensuring optimal starting conditions are achieved before combustion begins.
2Use of energy by moving object
If the MHSG increases engine rotation speed before fuel injection, then fuel economy improves, but the starting process takes longer
Solution Approach 1:
The system dynamically adjusts the cranking process by continuously monitoring engine rotation speed and automatically transitioning from cranking mode to fuel injection mode when the predetermined speed is reached. This dynamic control optimizes the balance between achieving fuel-efficient starting conditions and minimizing overall starting time.
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
This approach reduces fuel consumption and improves fuel economy by delaying fuel injection until the engine reaches a predetermined speed, optimizing the starting process.
Implementation Method 1
increasing a rotation speed of the engine by operating the MHSG by electricity supplied from a battery
Data Source
AI summary
A method for controlling starting of a mild hybrid vehicle includes receiving a starting-request signal and in response, increasing a rotation speed of the engine by driving the MHSG by electricity supplied from a battery. Status data of the mild hybrid vehicle for controlling starting of the engine is monitored to obtain an engine rotation speed from the status data and determine an injection-starting rotation speed based on the status data. When the engine rotation speed is greater than the injection-starting rotation speed, fuel injection of the engine is started.