Engine Control Device Deposit Removal Fuel Pressure
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Solution Overview
Problem
In direct-injection engines, deposits on fuel injection valves can lead to reduced fuel injection performance and combustion instability, particularly when lean air-fuel ratios are used, as increasing fuel pressure to remove deposits can disrupt the intended fuel-air mixture distribution.
Innovation Solution
An engine control device and method that adjusts fuel pressure and air-fuel ratios to accurately remove deposits from fuel injection valves, while restricting fuel pressure increases when lean combustion is performed to maintain combustion stability, by estimating deposition amounts and controlling the fuel pressure adjustment mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If fuel pressure is increased to remove deposits from the injection hole, then deposit removal performance is improved, but fuel injection precision deteriorates when lean combustion is performed
Solution Approach 1:
The fuel pressure is made dynamically adjustable based on combustion mode. The system switches between a first fuel pressure (higher) for standard combustion to remove deposits, and a second fuel pressure (lower or equal to first) for lean combustion to maintain injection precision. This dynamic adaptation resolves the contradiction by applying high pressure only when necessary for deposit removal, not during lean combustion where precision is critical.
Solution Approach 2:
The system changes the fuel pressure parameter according to the combustion mode. When lean combustion is detected (indicated by a specific air-fuel ratio), the fuel pressure is restricted from increasing even if deposit removal is needed. This parameter change based on operating conditions allows the system to prioritize injection precision during lean combustion while still enabling deposit removal during standard combustion modes.
2Object-affected harmful factors
If pulse width is decreased to increase fuel pressure, then deposit removal capability is improved, but combustion stability deteriorates
Solution Approach 1:
The pulse width is dynamically adjusted based on the combustion mode. During lean combustion, the system maintains a larger pulse width to ensure sufficient fuel injection amount and maintain combustion stability. During standard combustion modes, the system can use smaller pulse widths with higher fuel pressure to achieve deposit removal. This dynamic adjustment prevents combustion instability while enabling effective deposit removal.
Solution Approach 2:
The system changes both fuel pressure and pulse width parameters based on combustion mode. When lean combustion is performed, the fuel pressure is restricted from increasing and pulse width is maintained at a larger value. This coordinated parameter change ensures that combustion stability is preserved while still allowing deposit removal capabilities in other combustion modes.
3Object-affected harmful factors
If fuel pressure is increased to improve cleaning effect, then deposit removal is enhanced, but fuel-air mixture distribution uniformity deteriorates
Solution Approach 1:
The fuel pressure is dynamically controlled based on the detected combustion mode. The ECU restricts fuel pressure increase when lean combustion is detected, thereby maintaining uniform fuel-air mixture distribution. When standard combustion modes are detected, the system allows fuel pressure increase to achieve effective deposit removal. This dynamic control resolves the contradiction by adapting pressure levels to operational requirements.
Solution Approach 2:
The system implements parameter changes in fuel pressure based on combustion mode detection. By restricting fuel pressure increase during lean combustion, the system maintains the intended fuel-air mixture distribution uniformity. During standard combustion modes, the system allows pressure increases to improve cleaning effectiveness. This conditional parameter adjustment resolves the contradiction between cleaning effect and mixture uniformity.
Data Source
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AI summary
A controller for controlling a fuel injection valve and a fuel pressure adjustment mechanism sets an air-fuel ratio of a fuel-air mixture to be generated within a combustion chamber to an air-fuel ratio equal to or leaner than a theoretical air-fuel ratio, based on an operating condition of an engine; drives the fuel injection valve, based on the set air-fuel ratio; estimates a deposition amount of deposits on an injection hole of the fuel injection valve, based on an operating condition of the engine; causes the fuel pressure adjustment mechanism to increase the fuel pressure, when the estimated deposition amount of deposits exceeds a predetermined value; and restricts the fuel pressure from increasing, even when the estimated deposition amount of deposits exceeds the predetermined value, as far as the set fuel-air ratio is set to an air-fuel ratio leaner than the theoretical fuel-air ratio.