Engine Friction Generation via Valve Timing
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Solution Overview
Problem
Conventional engine braking in hybrid vehicles provides inconsistent deceleration assistance, especially when the battery is fully charged, leading to unexpected changes in vehicle deceleration rates, as the motor's braking assistance is lost, resulting in an inconsistent driving experience.
Innovation Solution
A system that adjusts the intake and exhaust valve time durations to increase engine friction on the drivetrain, enhancing mechanical friction and deceleration torque by modifying the duration for which the intake and exhaust valves are open, based on deceleration needs and drive modes, to provide consistent braking assistance even when battery regeneration is not available.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If battery regeneration is used to provide braking assistance in hybrid vehicles, then braking assistance is provided during deceleration, but the braking assistance is lost when the battery reaches peak state of charge, causing inconsistent deceleration
Solution Approach 1:
The patent changes the operating parameters of the engine by adjusting intake and exhaust valve timing durations to generate enhanced pumping losses. This creates artificial engine friction that provides consistent braking assistance regardless of battery charge state, resolving the inconsistency caused by battery regeneration limitations
2Force
If conventional engine braking is used when the engine is engaged with the drivetrain, then minimal braking assistance is provided, but it remains insufficient for effective vehicle deceleration
Solution Approach 1:
The patent modifies engine valve timing parameters (intake and exhaust valve durations) to create enhanced pumping losses that generate additional friction force on the drivetrain, transforming the engine from a power-generating device into a friction-generating braking device without requiring disengagement from the drivetrain
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 solution enhances vehicle deceleration performance by maintaining consistent engine friction, reducing the reliance on brakes and extending the lifespan of brake components, while providing a smoother driving experience by ensuring consistent deceleration across various driving conditions.
Implementation Method 1
adjust an intake valve time duration or an exhaust valve time duration to increase engine friction to enhance mechanical friction on a drivetrain of a vehicle
Data Source
AI summary
Methods and systems are described for enhanced engine friction generation. The enhanced engine friction generation improves the effectiveness of vehicle braking in deceleration fuel cut-off driving conditions by using engine vacuum and backpressure to temporarily increase engine pumping losses, thereby increasing powertrain drag and increasing deceleration torque to the wheels. The engine vacuum and backpressure may be created by changing the duration of the intake and/or exhaust valves. The system includes a processor and a non-transitory computer-readable storage medium storing instructions that, when executed by the processor, cause the processor to perform operations comprising adjusting an intake valve time duration or an exhaust valve time duration to increase engine friction to enhance mechanical friction on a drivetrain of a vehicle.