Atkinson Cycle Powertrain With Selective Compressor Boost
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Solution Overview
Problem
Atkinson cycle engines offer higher efficiency but suffer from low indicated mean effective pressure (IMEP), power density, and peak power compared to Otto cycle engines, and relying on an electric motor for additional torque can deplete battery energy.
Innovation Solution
A powertrain system combining an Atkinson cycle engine with a hybrid electric motor and a selectively actuatable compressor that pressurizes the air intake system, allowing the compressor to increase torque output without draining the battery, especially during prolonged high-torque demands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If an Atkinson cycle engine is used to improve efficiency, then thermal efficiency is improved, but power density and peak power are reduced
Solution Approach 1:
The patent combines an Atkinson cycle engine with a compressor and electric motor into a hybrid powertrain system. The compressor mechanically boosts air intake to increase engine power output, while the electric motor provides auxiliary torque. This merging allows the system to achieve both the efficiency benefits of the Atkinson cycle and the power output of a traditional Otto cycle engine.
Solution Approach 2:
The system dynamically changes operating parameters by selectively activating the compressor and electric motor based on power demands. The controller adjusts the degree of boosting and motor assistance to optimize the balance between efficiency and power output, allowing the engine to operate at optimal points while meeting varying power requirements.
2Power
If an electric motor is used to provide additional torque, then power output is improved, but battery energy is depleted
Solution Approach 1:
The compressor is designed to be self-powered by the engine through a belt drive system, eliminating the need for continuous battery power. The engine drives the compressor to mechanically boost air intake, and the system recovers some energy through the electric motor during deceleration. This self-service approach allows the system to maintain high power output without depleting battery energy.
3Power
If a compressor is added to increase torque output, then power density is improved, but device complexity increases
Solution Approach 1:
The electric motor serves multiple functions: it provides auxiliary torque during high power demands, powers the compressor during certain operating conditions, and acts as a generator to recover energy during deceleration. This multi-functionality reduces the need for separate dedicated components, thereby limiting the increase in system complexity while achieving improved power density.
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 enhances torque output of the Atkinson cycle engine without parasitic loss during low power modes and maintains battery energy by using the compressor to augment engine power, thereby improving vehicle performance without depleting the battery.
Implementation Method 1
a compressor configured to selectively compress air in the air intake system
Implementation Method 2
A spark plug generates a spark, causing the air and fuel in the cylinder to combust when the piston is at or near top dead center, generating pressure and forcing the piston to its bottom dead center position during an expansion stroke
Data Source
AI summary
A powertrain includes an Atkinson cycle engine having at least one cylinder, a crankshaft, and an air intake system that provides selective fluid communication between the at least one cylinder and the atmosphere. A motor is in hybrid combination with the engine, and a compressor is configured to selectively pressurize air in the air intake system. The powertrain provides the fuel efficiency of an Atkinson cycle engine while compensating for the reduced torque output of an Atkinson cycle engine.