Engine Control Device Compression Ratio Adjustment Fuel Cut Recovery
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Solution Overview
Problem
Conventional internal combustion engines with in-cylinder direct injection face challenges in reducing fuel adhesion to the piston and exhaust particulate discharge when restarting fuel injection after a fuel cut state, leading to increased exhaust particulate discharge and number.
Innovation Solution
A control device with a controller that adjusts the compression ratio and fuel injection strategy, including a rich spike and variable compression ratio mechanism, to minimize fuel adhesion and exhaust particulate discharge by lowering the compression ratio at fuel injection restart and returning it to normal after the spike.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If the fuel injection amount at one combustion cycle is decreased to enable split injection, then fuel adhesion to wall surfaces is decreased, but the injection amount ratio at the first time in split injection cannot be decreased when engine load is low
Solution Approach 1:
The patent changes the compression ratio parameter dynamically during fuel cut recovery to enable effective fuel adhesion control even when total fuel injection amount is low. By lowering compression ratio at restart, the invention achieves reduced fuel adhesion to piston walls despite limited fuel availability for split injection
Solution Approach 2:
The invention introduces dynamic compression ratio control that adapts to fuel cut recovery conditions. The compression ratio is temporarily lowered only during the critical restart phase, providing adaptive control that responds to real-time engine state without requiring complex injection timing adjustments
2Productivity
If fuel injection is restarted from fuel cut state with low engine load, then fuel injection can resume, but discharge amount and discharge number of exhaust particulate are increased
Solution Approach 1:
The patent changes compression ratio as a control parameter during fuel cut recovery to simultaneously achieve fuel injection resumption and exhaust particulate suppression. The temporary compression ratio reduction creates optimal conditions for fuel vaporization and combustion, reducing particulate formation during the critical restart phase
Solution Approach 2:
The invention performs preliminary compression ratio reduction before fuel injection restart to prepare the combustion environment. This preliminary action ensures that when fuel is reintroduced, the reduced compression ratio immediately begins reducing fuel adhesion and particulate discharge
3Loss of substance
If compression ratio is lowered at fuel injection restart, then fuel adhesion to piston is decreased, but engine load and combustion efficiency may be affected
Solution Approach 1:
The patent implements dynamic compression ratio control that is temporary and conditional, not permanent. The compression ratio is lowered only during the specific window of fuel cut recovery, then returned to normal, providing a dynamic solution that balances fuel adhesion reduction with power maintenance
Solution Approach 2:
The invention applies periodic compression ratio adjustment as part of the fuel cut recovery cycle. The compression ratio is temporarily reduced during restart, then restored to normal, creating a periodic control pattern that addresses fuel adhesion issues without sustained impact on engine power
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
Effectively decreases fuel adhesion to the piston and suppresses exhaust particulate discharge by optimizing the compression ratio and fuel injection timing in response to temperature changes, improving engine efficiency and emissions control.
Implementation Method 1
a variable compression ratio mechanism arranged to vary an upper dead center position of a piston, and thereby to vary a compression ratio of the internal combustion engine
Implementation Method 2
a controller configured to control a fuel injection valve arranged to directly inject a fuel into a combustion chamber
Implementation Method 3
the compression ratio at the restart of the fuel injection from the fuel cut being set to be smaller than a normal state compression ratio determined in accordance with a driving state as a temperature of a wall surface of the combustion chamber becomes lower, so as to decrease adhesion of the fuel injected from the fuel injection valve into a cylinder to the piston
Implementation Method 4
A rich spike by which the fuel injection amount from the fuel injection valve is temporarily increased is performed at the restart of the fuel injection from the fuel cut
Implementation Method 5
internal combustion engine
Data Source
AI summary
A control device for an internal combustion engine has a controller configured to control a fuel injection valve arranged to directly inject a fuel into a combustion chamber, and a variable compression ratio mechanism arranged to vary an upper dead center position of a piston, and thereby to vary a compression ratio of the internal combustion engine. The controller is configured to control a fuel cut by which the fuel injection from the fuel injection valve is stopped, when a predetermined fuel cut condition is satisfied during a traveling of a vehicle. The fuel injection from the fuel injection valve is restarted when a predetermined fuel cut recovery condition is satisfied during the fuel cut.