Hybrid EV Engine Start Control for Vibration and Response
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Solution Overview
Problem
Hybrid electric vehicles face challenges in starting the engine without causing excessive vibration, as starting combustion too early can lead to vibration but starting it too late delays the engine start.
Innovation Solution
A controller for hybrid electric vehicles that executes two distinct starting processes: the first process starts combustion after increasing the engine rotation speed to match the motor rotation speed, while the second process starts combustion before the engine rotation speed reaches the motor rotation speed, depending on the increase amount of the torque request value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If combustion is started after the motor generator is driven so that the crankshaft starts rotating, then the engine start is completed earlier, but vibration of the vehicle resulting from the engine start tends to occur
Solution Approach 1:
The patent changes the combustion start timing parameter based on the torque request value. When the torque request value is small, combustion is started after the crankshaft reaches motor rotation speed to minimize vibration. When the torque request value is large, combustion is started before the crankshaft reaches motor rotation speed to ensure timely engine start completion. This dynamic parameter adjustment resolves the contradiction between early engine start and vibration reduction.
2Object-affected harmful factors
If the time of starting combustion is delayed, then the occurrence of the vibration resulting from the engine start is limited, but it causes the engine start to be completed later
Solution Approach 1:
The patent implements a dynamic control strategy where the combustion start timing is not fixed but adapts based on real-time torque request conditions. The control system dynamically selects between two combustion start strategies: delaying combustion start to reduce vibration when torque demand is low, or advancing combustion start to ensure timely completion when torque demand is high. This dynamic approach allows the system to optimize the balance between vibration reduction and engine start timing based on actual operating conditions.
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
The solution effectively manages engine start timing to minimize vibration while ensuring the engine start is completed in a timely manner, depending on the torque request conditions.
Implementation Method 1
a motor generator (30) as a power source... by driving the motor generator
Implementation Method 2
combustion in the engine... causes combustion to be started in the engine
Data Source
AI summary
A controller is employed in a vehicle including an engine, a motor generator, and a hydraulically-driven clutch. The controller includes a CPU that executes: a first starting process that starts, when starting the engine under a condition in which an increase amount of a torque request value is less than an increase amount determination value, combustion in the engine after increasing an engine rotation speed to a motor rotation speed by engaging the clutch; and a second starting process that starts, when starting the engine under a condition in which the increase amount of the torque request value is greater than or equal to the increase amount determination value, combustion in the engine after the crankshaft starts to be rotated by engaging the clutch, the combustion being started before the engine rotation speed reaches the motor rotation speed.