Hybrid Supercharger Torque Control via Electric Motor-Generator
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Solution Overview
Problem
Smaller engines provide less torque than larger engines, and existing supercharger systems are inefficient at low engine speeds, as they rely on engine rotational speed to boost torque, limiting their effectiveness in providing consistent torque across a range of engine speeds.
Innovation Solution
A supercharger assembly that includes a Roots-type supercharger with a planetary gearing arrangement and an electric motor-generator, allowing for independent control of boost pressure and torque distribution through a clutch and brake system, enabling efficient torque generation at low engine speeds by converting throttling losses into stored energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a smaller engine is used, then fuel economy and cost are improved, but torque output deteriorates
Solution Approach 1:
The patent combines a mechanical supercharger driven by the engine crankshaft with an electric motor-generator to create a hybrid supercharger system. This merging allows the smaller engine to receive boost pressure assistance from both mechanical and electrical sources, compensating for the reduced torque output while maintaining fuel economy benefits of the smaller displacement engine.
Solution Approach 2:
The electric motor-generator acts as an intermediary between the engine and the supercharger system. It can provide additional torque to the supercharger when the engine torque is insufficient, and can also function as a generator to recover energy during deceleration, thereby addressing the torque deficiency of smaller engines without compromising fuel efficiency.
2Force
If a conventional supercharger is used, then torque is boosted at high engine speeds, but effectiveness deteriorates at low engine speeds
Solution Approach 1:
The hybrid supercharger system dynamically adjusts the contribution of the electric motor-generator based on engine speed and torque demands. At low engine speeds, the electric motor provides supplemental torque to the supercharger to maintain effective boost pressure. At high engine speeds, the mechanical drive from the crankshaft becomes sufficient and the electric motor can be disengaged or used for energy recovery, optimizing performance across the entire operating range.
Solution Approach 2:
The system changes operational parameters by controlling the electric motor-generator's engagement and power output based on real-time engine conditions. The control system adjusts the electric torque contribution, supercharger speed, and clutch engagement states to maintain optimal torque boost effectiveness across varying engine speeds, particularly enhancing low-speed performance.
3Ease of operation
If throttling losses are increased to control air flow, then air flow control is improved, but energy efficiency deteriorates
Solution Approach 1:
The patent converts the harmful throttling losses into beneficial electrical energy. The electric motor-generator is controlled to operate as a generator during deceleration and low-load conditions, recovering kinetic energy that would otherwise be lost through throttling. This energy recovery reduces the overall energy loss while maintaining precise air flow control through the throttle valve.
Solution Approach 2:
The control system continuously monitors engine operating conditions, air flow demands, and energy state to optimally manage throttle position and electric motor-generator operation. This feedback control allows the system to minimize throttling losses by coordinating throttle opening with electric motor assistance, reducing the pressure drop across the throttle while maintaining required air flow control.
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 system provides consistent torque across a wide range of engine speeds by using the electric motor-generator to adjust boost pressure and convert throttling losses into electrical energy, enhancing engine efficiency and fuel economy.
Implementation Method 1
an electric motor-generator (50) that is selectively alternately operable as a motor and as a generator
Implementation Method 2
planetary gearing arrangement (41) with a sun gear member (42) that is connected for common rotation with the first shaft (30)
Implementation Method 3
a brake (68) selectively engageable to hold the first shaft (30) stationary
Implementation Method 4
a clutch (55) selectively engageable to operatively connect the second member for rotation with the engine crankshaft (48)
Data Source
AI summary
A supercharger assembly includes a supercharger in series with an engine that has a crankshaft and has an air intake manifold defining a plenum through which air flow is provided to the engine. A supercharger is upstream of the plenum in air flow to the engine and has a first rotor rotatable with a first shaft and a second rotor rotatable with a second shaft. The supercharger assembly also includes an electric motor-generator that is selectively alternately operable as a motor and as a generator, and a planetary gearing arrangement having a first member operatively connected to the electric motor-generator, a second member connectable to be rotated by the engine crankshaft, and a third member operatively connected for rotation with the first shaft. The supercharger assembly has only two selectively engageable torque-transmitting mechanisms and a control system configured to control the electric motor-generator and the torque-transmitting mechanisms.