Hybrid Engine Intake Valve Timing for Deceleration Efficiency
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Solution Overview
Problem
In hybrid vehicles, when the internal combustion engine is not completely decoupled from the driven wheels, shutting off the fuel supply during deceleration leads to spin and pumping losses, reducing fuel efficiency and energy recovery for battery recharging.
Innovation Solution
A method and system that control the hybrid electric vehicle by ceasing fuel supply to the engine and closing intake valves at specific predetermined instances to minimize compression pulses and energy losses, with a concentric camshaft mechanism regulating the valves to optimize energy recovery during deceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the engine's fuel supply is shut off during vehicle deceleration, then fuel efficiency is improved, but spin and pumping losses increase and energy recovery is reduced
Solution Approach 1:
The patent divides the single intake valve control into two separate control mechanisms: a first intake valve controlled by a first camshaft and a second intake valve controlled by a second camshaft. This segmentation allows independent timing control of each valve, enabling the first valve to close at a first camshaft position and the second valve to close at a second camshaft position, thereby optimizing the compression pulse to reduce pumping losses while maintaining fuel efficiency benefits during deceleration.
Solution Approach 2:
The patent implements dynamic valve timing control where the closing positions of the intake valves are varied based on engine operating conditions. During deceleration with fuel supply shut off, the valves close at specific camshaft positions that minimize compression pulses and pumping losses. This dynamic adjustment of valve timing allows the engine to adapt to different operating states, reducing energy losses during coasting while maintaining efficiency during powered operation.
2Reliability
If the engine is permanently coupled to driven wheels, then mechanical connection is maintained, but pumping losses increase during deceleration
Solution Approach 1:
The patent applies preliminary action by closing the intake valves at predetermined camshaft positions before the piston reaches top dead center during deceleration. This提前 closing of valves creates a controlled compression pulse that minimizes the pressure differential across the valves, thereby reducing pumping losses while maintaining the mechanical connection between the engine and driven wheels. The valve closing timing is pre-determined based on camshaft position to optimize performance during coasting.
3Device complexity
If the second intake valve is closed at the first predetermined instance, then valve timing is simplified, but excessive air is forced into the three-way catalyst
Solution Approach 1:
The patent segments the intake valve control into two independently timed valves, allowing the first intake valve to close at a first camshaft position and the second intake valve to close at a second camshaft position. This segmentation enables precise control over the amount of air entering the cylinder and subsequently the three-way catalyst, preventing excessive air intake while maintaining manageable control complexity through dedicated camshaft mechanisms for each valve.
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 reduces spin and pumping losses, enhances fuel efficiency, and increases energy recovery for the motor-generator during deceleration, while ensuring efficient engine restart and reduced oxygen intake in the three-way catalyst for improved fuel consumption.
Implementation Method 1
a magnitude of compression pulses in the cylinder during deceleration is reduced
Implementation Method 2
an amount of energy recovered by the motor-generator to recharge the energy-storage system
Implementation Method 3
an exhaust system that includes a three-way catalyst
Data Source
AI summary
A method is provided for controlling a hybrid electric vehicle that includes an internal combustion engine having a cylinder with first and second intake valves and a piston configured to rotate the engine's crankshaft. The method includes determining whether deceleration of the vehicle is desired and ceasing supply of fuel to the cylinder when such condition is satisfied. The method also includes closing the first intake valve at a first predetermined instance and closing the second intake valve at a second predetermined instance via a specifically configured device when the fuel supply has been ceased. The second predetermined instance is after the first predetermined instance relative to rotational position of the crankshaft and magnitude of compression pulses in the cylinder during deceleration is reduced relative to when the cylinder is being fueled. A system for controlling the hybrid vehicle and a vehicle employing such a system are also provided.