ISG Torque Assist for Low-Inertia Engine Speed Stability
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Solution Overview
Problem
Conventional internal combustion engines experience significant speed variation due to reduced inertial mass at low and idle speeds, leading to increased emissions and inefficiencies.
Innovation Solution
Implementing an Integrated Starter Generator (ISG) in motoring mode with electric torque assist during specific strokes of the engine cycle to compensate for reduced inertia, using a sensing assembly, MOSFET bridge, and control unit to manage the ISG's operation based on crankshaft speed and position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the number of cylinders in a conventional internal combustion engine is increased to reduce torque fluctuations, then the engine's overall torque output increases, but the engine dimensions and weight increase
Solution Approach 1:
The patent combines a conventional internal combustion engine with an electric motor to form a hybrid power system. The electric motor is coupled to the crankshaft to provide additional torque, allowing the reduction of cylinder count while maintaining or increasing total torque output. This merging of two different power sources resolves the contradiction by achieving higher torque without proportionally increasing engine weight.
Solution Approach 2:
An inertia element is introduced as an intermediary component between the internal combustion engine and the electric motor. This inertia element smooths torque fluctuations from both power sources, allowing for more flexible engine configuration. The mediator enables the system to achieve stable torque delivery without requiring a high cylinder count, thus avoiding the weight penalty.
2Stability of the object's composition
If the number of cylinders is increased to smooth torque delivery, then torque fluctuations are reduced, but the engine complexity increases
Solution Approach 1:
The inertia element serves as a mediator that smooths torque fluctuations without requiring multiple cylinders. By introducing this single intermediate component, the system achieves stable torque delivery while maintaining a simpler engine configuration with fewer cylinders, thus reducing overall engine complexity.
Solution Approach 2:
The patent replaces the traditional mechanical solution of increasing cylinder count with an electromechanical hybrid system. The electric motor, controlled by an electronic control unit, provides torque supplementation and smoothing, substituting the need for a complex multi-cylinder mechanical configuration.
3Weight of stationary object
If a smaller engine is used to reduce dimensions and weight, then the engine size decreases, but the torque output becomes insufficient
Solution Approach 1:
The patent merges a compact internal combustion engine with an electric motor to create a hybrid power system. The smaller engine is supplemented by the electric motor's torque contribution, achieving sufficient total torque output without the weight penalty of a large conventional engine. This combination resolves the contradiction by decoupling the relationship between engine size and torque output.
Solution Approach 2:
The system dynamically adjusts the torque contribution from each power source based on operating conditions. The electric motor provides variable torque assistance, allowing the smaller engine to operate efficiently across a wider range of conditions while maintaining sufficient total torque output, thus resolving the size-torque trade-off.
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
Enhances engine speed stability and reduces emissions by optimizing torque delivery, allowing the engine to operate on a leaner fuel-air mixture, thereby improving efficiency and emission control.
Implementation Method 1
an electric motor (40) which is coupled to the crankshaft (11) in order to generate a force in order to rotate the crankshaft
Data Source
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AI summary
Embodiments herein provide a system and method for using an Integrated Starter Generator (ISG) for electric torque assistance on specific strokes of a 2-stroke or 4-stroke Internal Combustion (IC) engine (300) with reduced inertial mass than a conventional inertial mass loaded IC engine in order to overcome a speed variation problem caused by the engine's lower inertia at low and idle speeds and thus meeting a crankshaft speed shortfall. Furthermore, enabling the 2-stroke and 4-stroke engines to run on a lean fuel-air mixture improves emissions at low and idling speeds, and leads to better IC engine emission control.