HCCI Valve Timing Control for Cylinder Combustion Balance

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Solution Overview

Problem

Existing engine control systems struggle to balance combustion characteristics across cylinders, leading to inefficient engine performance, as they lack the ability to independently control intake and exhaust valve timings in camshaft-based systems.

Innovation Solution

The implementation of a fully flexible valve actuation system, where an engine control module determines crankshaft angles for fuel combustion and adjusts intake or exhaust valve closing timings using an angle determination and control module, allowing for separate control of intake and exhaust valves to achieve balanced combustion across all cylinders.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If camshaft-based valve timing control is used, then mechanical simplicity is maintained, but independent control of intake and exhaust valve timings is not achieved

Engineering Contradiction:

Improveindependent valve timing controlVSAvoidvalve actuation system

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent divides the valve control system into independent intake valve actuation and exhaust valve actuation mechanisms. Each valve can be controlled separately through individual camshaft profiles or electronic actuators, enabling independent timing adjustment without requiring complex coordinated control of multiple valves simultaneously.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements variable valve timing control where intake and exhaust valve timings can be dynamically adjusted during different engine operating conditions. This allows the system to adapt valve opening/closing moments to optimize combustion characteristics for HCCI operation while maintaining the ability to simplify control under steady-state conditions.

Inventive Principle:

Principle #15Dynamics

2Productivity

If valve closing timing is not optimized for HCCI combustion, then combustion efficiency is reduced, but timing control complexity increases

Engineering Contradiction:

Improvecombustion efficiencyVSAvoidtiming control system

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent optimizes valve closing timing parameters specifically for HCCI combustion mode. By adjusting the timing parameters of intake and exhaust valves based on combustion phasing and pressure characteristics, the system achieves optimized combustion efficiency without requiring overly complex control algorithms, as the timing adjustments follow established HCCI combustion principles.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS9334811B2Valve control systems and methods for homogenous charge compression ignition operation

Publication Date: 2016.05.10 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

An engine control method for a vehicle includes: determining a crankshaft angle where a predetermined percentage of fuel injected into a cylinder was combusted during homogenous charge compression ignition (HCCI) operation of an engine; determining a valve closing timing adjustment for one of an intake valve and an exhaust valve of based on the crankshaft angle; generating a valve closing timing for the one of the intake valve and the exhaust valve of the cylinder based on the valve closing timing adjustment; and closing the one of the intake valve and the exhaust valve of the cylinder based on the valve closing timing.