Engine Control Device for Turbocharger Boost Pressure Management
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Solution Overview
Problem
In engines with turbochargers, low load operating conditions lead to insufficient fuel and intake air mixing, resulting in decreased combustion efficiency, potential fuel economy deterioration, and issues like oil dilution and carbon formation, which existing control systems fail to adequately address.
Innovation Solution
A control apparatus that adjusts the injection amounts and ratios of fuel injection valves and the open/closed state of the waste gate valve based on engine operating states, optimizing intake air flow and preventing excessive boost pressure to enhance combustion stability and fuel economy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the injection amount of fuel injected from the second fuel injection valve is increased in accordance with an increase in load or speed of the engine, then combustion efficiency is improved, but excessive boost pressure may occur causing damage to the engine or supercharger
Solution Approach 1:
The control device monitors the injection amount from the second fuel injection valve and uses this information to control the waste gate valve. When the injection amount exceeds a predetermined threshold, the waste gate valve is opened to reduce boost pressure, creating a feedback loop that prevents excessive pressure while allowing high injection amounts for improved combustion efficiency.
Solution Approach 2:
The waste gate valve acts as an intermediary component between the turbocharger system and the exhaust bypass passage. It mediates the boost pressure by opening or closing the exhaust bypass passage based on the injection amount, thereby protecting the engine and supercharger from excessive pressure while enabling improved combustion.
2Reliability
If the waste gate valve is opened to suppress excessive boost pressure, then engine safety is improved, but combustion stability may deteriorate due to insufficient fuel and intake air mixing
Solution Approach 1:
The waste gate valve control is made dynamic rather than static. The valve opening is adjusted in real-time based on the injection amount from the second fuel injection valve. This dynamic control allows the system to maintain combustion stability by only opening the waste gate valve when necessary (when injection amount exceeds threshold), rather than keeping it constantly open or closed.
Solution Approach 2:
The control system changes the operational parameters of the waste gate valve (opening/closing state) based on changes in the injection amount parameter. By linking the waste gate valve control to the injection amount, the system optimizes both engine safety and combustion stability through parameter coordination.
Data Source
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AI summary
A control apparatus of an engine comprises: fuel injection control means for controlling injection amounts of fuel injected from a first fuel injection valve, which injects fuel into an intake path of the engine, and a second fuel injection valve, which injects fuel into a combustion chamber of the engine, in accordance with the operating state of the engine; and valve control means for changing the open/closed state of the waste gate valve in accordance with the injection amounts of fuel injected from the first fuel injection valve and the second fuel injection valve. The fuel injection control means increases the injection amount of fuel injected from the second fuel injection valve in accordance with an increase in the load or speed of the engine. The valve control means changes the open/closed state of the waste gate valve in the sequence of an opening direction, a closing direction, and an opening direction as the injection amount of fuel injected from the second fuel injection valve increases.