Hybrid Powertrain Torque Control via Variable Displacement
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Solution Overview
Problem
Conventional internal combustion engines face challenges in achieving optimal energy efficiency and fuel economy due to limited engine size options and varying load conditions, leading to suboptimal fuel efficiency across different operating conditions.
Innovation Solution
A hybrid powertrain system that alternates between different effective displacements of an internal combustion engine, using a motor/generator unit and energy storage devices like ultracapacitors to adjust torque and optimize energy efficiency, allowing the engine to operate at fractional displacements and reduce pumping losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a single conventional engine is used, then the engine structure is simple, but the fuel efficiency is suboptimal under varying load conditions
Solution Approach 1:
The engine dynamically adjusts the number of active cylinders based on real-time load conditions. The control system monitors engine operating parameters and selectively activates or deactivates cylinders to match the current power demand, enabling the engine to adapt its displacement to varying load conditions and maintain optimal fuel efficiency across different operating ranges.
Solution Approach 2:
The engine is segmented into multiple independently controllable cylinder groups. Each cylinder or cylinder bank can be individually activated or deactivated based on load requirements. This segmentation allows the engine to operate with only the necessary number of cylinders for the current power demand, improving fuel efficiency by avoiding the operation of excess cylinders under light load conditions.
2Power
If more cylinders are activated to meet peak power demand, then the power output is sufficient, but the fuel efficiency deteriorates under partial load conditions
Solution Approach 1:
The engine employs partial action by activating only the necessary number of cylinders required to meet the current power demand rather than operating all cylinders continuously. Under partial load conditions, only a subset of cylinders is active, providing exactly enough power for the current demand without the excess energy consumption that would result from operating all cylinders. This partial operation significantly improves fuel efficiency while maintaining sufficient power output.
3Use of energy by moving object
If cylinder deactivation is used, then the fuel economy is improved, but the system complexity increases due to control mechanisms
Solution Approach 1:
The engine control system automatically monitors operating conditions and autonomously determines when to activate or deactivate cylinders based on real-time power demand. The system self-adjusts without requiring manual intervention or complex external control mechanisms, using onboard sensors and a control unit to manage cylinder deactivation and activation sequences, thereby improving fuel economy while keeping the control system complexity manageable.
4Use of energy by moving object
If engine displacement is reduced, then the fuel consumption is lowered, but the power delivery capability is insufficient for varying load requirements
Solution Approach 1:
The engine dynamically adjusts its effective displacement by selectively activating or deactivating cylinders in response to varying load conditions. When power demand is low, the engine operates with reduced displacement (fewer active cylinders) to lower fuel consumption. When power demand increases, the engine activates additional cylinders to increase displacement and restore full power delivery capability. This dynamic adjustment allows the engine to optimize fuel consumption across different operating conditions while maintaining the ability to deliver required power when needed.
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 enhances fuel economy by maintaining engine cylinders at peak efficiency while delivering the desired powertrain output, reducing brake-specific fuel consumption and improving overall energy efficiency compared to conventional systems.
Implementation Method 1
A motor/generator unit or other suitable device may be used to add and subtract torque from the powertrain
Implementation Method 2
energy drawn from an energy storage device is used to add torque to the powertrain
Data Source
AI summary
Methods and arrangements for controlling hybrid powertrains are described. In one aspect, an engine is alternatingly operated at different effective displacements. One displacement delivers less than a requested powertrain output and the other delivers more. A motor/generator system is used to add and subtract torque to/from the powertrain to cause the net delivery of the requested powertrain output. In some embodiments, energy added and subtracted from the powertrain is primarily drawn from and stored in a capacitor (e.g., a supercapacitor or an ultracapacitor) when alternating between effective displacements. In another aspect a hybrid powertrain arrangement includes an engine a motor/generator and an energy storage system that includes both a battery and a capacitor. The capacitor stores and delivers electrical energy to the motor/generator unit during operation of the engine in a variable displacement or skip fire mode.