Vehicle Controller Fuel Cut Pumping Loss Reduction
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Solution Overview
Problem
The existing systems for regenerating kinetic energy into electrical energy during fuel cut in internal combustion engines suffer from increased pumping loss and inefficient energy-regenerate efficiency, especially when the throttle valve is closed and intake air pressure is decreased.
Innovation Solution
A vehicle controller system that includes a throttle valve, an EGR valve, and a variable valve timing controller, which coordinates the fuel-cut-control by closing the throttle valve, opening the EGR valve, and adjusting valve timing to reduce pumping loss and improve energy-regenerate efficiency by recirculating EGR gas and optimizing valve operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the throttle valve is closed during fuel cut to decelerate the vehicle, then the braking force is ensured, but the intake air pressure decreases causing increased pumping loss and deteriorated energy-regenerate efficiency
Solution Approach 1:
The EGR gas acts as an intermediary substance that is introduced into the intake passage to compensate for the intake air pressure drop caused by throttle valve closure. This mediator maintains the pressure level while the throttle remains closed, thereby ensuring both braking force and reducing pumping loss
Solution Approach 2:
The system changes the composition parameter of the intake gas by mixing EGR gas with fresh air. This parameter change allows the intake air pressure to be maintained at an appropriate level even when the throttle valve is closed, reducing pumping loss while preserving braking capability
2Loss of energy
If the EGR valve is opened during fuel cut to recirculate exhaust gas and reduce pumping loss, then energy-regenerate efficiency is improved, but the temperature decrease of the catalyst may occur
Solution Approach 1:
The EGR valve is opened to a controlled extent rather than fully, introducing only the necessary amount of EGR gas to maintain intake pressure and reduce pumping loss, while limiting the quantity to prevent excessive temperature drop that would affect catalyst performance
Solution Approach 2:
The control device monitors intake air pressure and engine operating conditions to dynamically adjust the EGR valve opening degree, creating a feedback mechanism that balances pumping loss reduction with catalyst temperature maintenance based on real-time conditions
3Loss of energy
If the variable valve timing controller adjusts valve timing to reduce pumping loss, then energy-regenerate efficiency is improved, but the device complexity increases
Solution Approach 1:
The variable valve timing mechanism dynamically adjusts the valve opening and closing timings based on engine operating conditions during fuel cut. This dynamic adjustment optimizes the valve timing to reduce pumping loss while utilizing existing variable timing hardware, avoiding additional complexity
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 effectively reduces pumping loss and enhances energy-regenerate efficiency by avoiding intake pressure drops and temperature decreases, while ensuring sufficient braking force and ignitability, thereby improving the overall energy conversion process.
Implementation Method 1
a kinetic energy of vehicle is regenerated by converting the kinetic energy into an electrical energy by an alternator
Implementation Method 2
the EGR valve is opened, and the variable valve timing controller is controlled so that a pumping loss of the internal combustion engine is decreased when the internal combustion engine is in the fuel cut
Data Source
AI summary
A vehicle controller performs a throttle-valve-late-close control in which the throttle valve is held open until a delay time has passed after the fuel cut is started, and an EGR-valve-open-close control in which the EGR valve is repeatedly opened and closed. Then, the throttle valve is closed and the EGR valve is opened. In a period from a latter period of an exhaust stroke to a preceding period of an intake stroke, a valve-overlap control is executed so that a variable valve timing controller is controlled to make both an intake valve and an exhaust valve opened. A pumping loss of an engine is sufficiently reduced and an energy-regenerate efficiency can be effectively improved.