Hybrid Vehicle Launch Control for Engine Clutch Lock-Up
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Solution Overview
Problem
Hybrid electric vehicles face issues with launching when the engine clutch is stuck in a lock-up state, leading to overdischarging of the main battery as the electric motor cannot function as a load, and the battery is only charged through a low DC-DC converter, which is inefficient.
Innovation Solution
A method of controlling the hybrid electric vehicle to maintain engine running and execute a slip launch using engine power, switching to electric motor power if engine stall conditions are met, and charging the main battery using a second motor connected to the engine, with a system of controllers managing the clutch and motor operations to prevent overdischarging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the engine clutch is stuck in a lock-up state, then the hybrid electric vehicle can be launched using engine power, but the main battery will overdischarge because the electric motor cannot function as a load
Solution Approach 1:
The system dynamically switches between two launch modes: slip launch (using transmission clutch slip) when the engine clutch is normal, and lock-up launch (using engine clutch lock-up) when stuck. This dynamic adaptation allows the vehicle to maintain launch capability while managing battery discharge based on the actual clutch state.
Solution Approach 2:
The control system changes operational parameters based on clutch state detection. When lock-up stuck is detected, the system switches from slip launch mode to lock-up launch mode, and simultaneously activates the electric motor as a generator to charge the main battery, thereby changing the energy flow parameters to prevent overdischarge.
2Stability of the object's composition
If the electric motor does not function as a load to prevent engine stall, then engine stability is maintained, but the main battery cannot be charged and will overdischarge
Solution Approach 1:
The electric motor is designed to perform multiple functions: as a drive motor during normal operation, as a generator for battery charging when the engine clutch is lock-up stuck, and as a load to prevent engine stall. This multi-functionality allows the system to adapt to different clutch states and maintain both engine stability and battery charge balance.
Solution Approach 2:
The system converts the harmful condition of lock-up stuck into a beneficial operation mode. Instead of simply preventing engine stall by keeping the electric motor idle, the system uses the electric motor as a generator to charge the main battery, transforming the problematic situation into an opportunity for battery charging while still maintaining engine stability through alternative means.
3Reliability
If the hybrid electric vehicle launches using only engine power in lock-up stuck state, then launch is possible, but the assistant battery overdischarges because it can only be charged through the main battery
Solution Approach 1:
The control system performs preliminary detection of the engine clutch state before launch. When lock-up stuck is detected, the system proactively activates the electric motor as a generator to charge the main battery before the assistant battery can overdischarge, preventing the cascading energy deficiency problem.
Solution Approach 2:
The system continuously monitors the state of charge of both the main battery and assistant battery, as well as the engine clutch state. Based on this feedback, the control system adjusts the electric motor's operation mode to ensure that the main battery is charged when needed, thereby preventing overdischarge of both batteries during launch in lock-up stuck condition.
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 effective launch of the hybrid electric vehicle in a lock-up stuck situation while preventing main battery overdischarging by allowing power generation from the electric motor and starting the engine when necessary, thus rapidly addressing engine stall conditions.
Implementation Method 1
charging a main battery using a second motor connected to the engine
Implementation Method 2
an engine clutch (EC) are disposed between an engine and an electric motor
Data Source
AI summary
Disclosed are a hybrid electric vehicle, which may be effectively launched when an engine clutch to connect an engine and an electric motor for driving is fixed in a lock-up state, and a method of controlling the same. A method of controlling launch of a the hybrid electric vehicle provided with an engine clutch disposed between a first motor and an engine includes determining whether or not the engine clutch is in a lock-up state, securing running of the engine, upon determining that the engine clutch is in the lock-up state, executing slip launch of the hybrid electric vehicle using power of the engine, and launching the hybrid electric vehicle using power of the first motor, if first conditions by stall of the engine are satisfied. Execution of slip launch of the hybrid electric vehicle includes charging a main battery using a second motor connected to the engine.