Planetary Gear Disconnect for Hybrid Drive Fuel Efficiency
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Solution Overview
Problem
Conventional drive systems for hybrid vehicles are fuel-intensive and have limited torque range at low loads due to the use of clutch mechanisms, which result in increased fuel consumption and wear, and are not optimized for efficient operation across various operating conditions.
Innovation Solution
A method that controls the drive system by determining whether the torque from the combustion engine and electrical machine is sufficient to operate the vehicle with the planetary gear in a release position, allowing simultaneous control of both engines to maintain low engine speed and reduce fuel consumption, while switching to a locked position when conditions are not met.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional clutch mechanism is used to disconnect the combustion engine during shifting, then the gearbox can be shifted, but the clutch mechanism experiences heating, increased fuel consumption, and wear
Solution Approach 1:
The invention extracts and removes the conventional clutch mechanism from the drivetrain, replacing it with a planetary gear-based disconnect system. The planetary gear can disengage the combustion engine from the gearbox without requiring friction-based clutch discs, thereby eliminating the associated energy losses and wear while maintaining shifting capability.
Solution Approach 2:
The invention replaces the friction-based mechanical clutch system with a planetary gear mechanism that uses mechanical locking and unlocking. This substitution eliminates the need for friction engagement, reducing energy losses and heat generation while achieving the same functional outcome of disconnecting the engine during gear shifts.
2Ease of operation
If a conventional clutch mechanism is used, then the gearbox can be shifted, but the clutch mechanism becomes heavy and occupies large space
Solution Approach 1:
The invention extracts and removes the heavy conventional clutch mechanism from the drivetrain. By eliminating the clutch discs, pressure plates, and associated hydraulic systems, the overall weight of the moving components is significantly reduced while maintaining the essential function of disconnecting the engine during gear changes.
3Adaptability or versatility
If the planetary gear is kept in locked position for all operating conditions, then the vehicle can operate in all modes, but fuel consumption increases at low loads
Solution Approach 1:
The invention implements dynamic control of the planetary gear position based on real-time operating conditions. The system automatically transitions between locked and release positions according to vehicle speed, load, and driving mode, optimizing fuel efficiency by disengaging the combustion engine during low-load conditions while maintaining full operational capability when needed.
Solution Approach 2:
The invention changes the operational parameters of the drivetrain by allowing the planetary gear to switch between two distinct states (locked and release). This parameter change enables the system to adapt to varying operating conditions, selecting the most efficient configuration for each scenario rather than maintaining a fixed locked state.
4Loss of energy
If the planetary gear is placed in release position at low loads, then fuel consumption decreases, but the torque range becomes limited
Solution Approach 1:
The system dynamically adjusts the planetary gear position based on torque requirements. When high torque is needed, the system locks the planetary gear to engage the combustion engine. When torque requirements are low, the system releases the planetary gear to allow electric-only operation, thereby optimizing the balance between fuel consumption and available torque.
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 by minimizing friction losses, enhances torque range at low loads, and optimizes engine speed for improved exhaust temperature management, enabling more efficient vehicle operation and reduced emissions.
Implementation Method 1
The planetary gear is arranged between the combustion engine and the gearbox, with components including a sun wheel connected to the combustion engine output shaft, a ring gear connected to the electrical machine rotor, and a planetary wheel carrier connected to the gearbox input shaft
Data Source
AI summary
Method for control of a drive system comprising a combustion engine with output shaft, gearbox with input shaft, electrical machine, and planetary gear comprising a sun wheel, a ring gear and a planetary wheel carrier. The method comprises, if torque from the combustion engine and the electrical machine is sufficient for the operation of the vehicle with the planetary gear in the release position, and if the vehicle's fuel consumption with the planetary gear in the release position is lower than in the locked position, controlling the electrical machine and the combustion engine such that the requested torque is provided, with the planetary gear in the release position. Otherwise, set the planetary gear in the locked position. A second locking means adapted to divide the combustion engine's output shaft in two sections in a release position, kept in a locked position if the planetary gear is in the release position.