Selective Fuel Vapor Purge for SI-HCCI Engine Mode Control
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Solution Overview
Problem
Internal combustion engines face challenges in efficiently transitioning between spark ignition (SI) and homogeneous charge compression ignition (HCCI) modes due to uncertainties in fuel vapor purging, which affect autoignition timing and aftertreatment issues, especially with high manifold pressures and sensitive air-fuel ratio changes.
Innovation Solution
An internal combustion engine with a gasoline fuel injection system and a fuel vapor purge system that allows selective delivery of evaporated fuel vapors to combustion cylinders, enabling operation in both SI and HCCI modes while reducing uncertainties in autoignition timing by controlling fuel vapor purging based on cylinder mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If fuel vapor purge system delivers evaporated fuel vapors to all combustion cylinders, then fuel vapor utilization is maximized, but autoignition timing uncertainty increases and HCCI operation becomes unreliable
Solution Approach 1:
The fuel vapor purge system is configured to deliver evaporated fuel vapors selectively to specific combustion cylinders based on their operational mode. Cylinders operating in SI mode receive fuel vapor purge, while cylinders in HCCI mode do not, thereby providing localized quality control that prevents autoignition timing uncertainty in HCCI cylinders while maintaining fuel vapor utilization efficiency in SI cylinders
Solution Approach 2:
The combustion cylinder population is segmented into two distinct groups based on combustion mode: SI mode cylinders that receive fuel vapor purge and HCCI mode cylinders that do not. This segmentation allows independent control of fuel vapor delivery to each group, resolving the contradiction between maximizing fuel vapor utilization and ensuring reliable HCCI operation
2Adaptability or versatility
If engine operates in multiple combustion modes (SI and HCCI), then fuel efficiency and emissions performance improve, but purge system complexity increases
Solution Approach 1:
The fuel vapor purge system incorporates dynamic control capabilities that adjust purge delivery based on real-time combustion mode detection. The system can transition between different purge strategies (full purge, selective purge, no purge) depending on whether SI or HCCI mode is active, enabling adaptability to multiple combustion modes without requiring completely separate purge systems for each mode
Solution Approach 2:
The fuel vapor purge control system is designed with multi-functionality to handle both SI and HCCI combustion modes through a single integrated control architecture. By using combustion mode detection to automatically select appropriate purge strategies, the system eliminates the need for separate purge control mechanisms for each combustion mode, thereby reducing overall system complexity while maintaining versatility
3Reliability
If high manifold pressures are used in HCCI mode, then compression ignition reliability improves, but fuel vapor concentration uncertainties increase
Solution Approach 1:
The control system takes preliminary anti-action by preventing fuel vapor purge delivery to HCCI mode cylinders before combustion occurs. By proactively disabling fuel vapor intake for HCCI cylinders, the system eliminates the source of concentration uncertainty rather than attempting to measure and compensate for it, thereby maintaining HCCI reliability under high manifold pressure conditions
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 solution allows for efficient use of evaporated fuel vapors, improves HCCI operation by reducing uncertainties in autoignition timing, and effectively handles the purge issues associated with multiple ignition modes, enhancing engine performance and emissions control.
Implementation Method 1
evaporated fuel vapors from a fuel vapor purge source to the combustion cylinders
Implementation Method 2
fuel vapor purging system configured to selectively control delivery of evaporated fuel vapors
Implementation Method 3
combust a mixture of air and gasoline
Data Source
AI summary
An internal combustion engine having a plurality of combustion cylinders and a fuel delivery system. The plurality of combustion cylinders are configured to receive a mixture of gasoline and air and combust such mixture, where some of the combustion cylinders are configured to operate in a spark ignition mode, with the remaining cylinders being configured to operate in a compression ignition mode. The engine may be configured to operate so that fuel vapor purge is added only to cylinders operating in the spark ignition mode. Alternatively, the engine may be operated in either a first purge mode, in which fuel vapor purge is added only to spark ignition cylinders, or a second purge mode, in which fuel vapor purge is added to spark ignition cylinders and compression ignition cylinders. Additionally, even where purge is added to spark ignition cylinders and compression ignition cylinders, air-fuel control may be based on exhaust sensor data from spark ignition cylinders, without reference to any such data from compression ignition cylinders.