Engine Controller Reduces Actuator Size via Intake Pressure
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Solution Overview
Problem
Existing internal combustion engine systems require large actuators to open recirculation valves during fuel cut-off processes due to significant pressure differences between exhaust and intake passages, leading to actuator enlargement issues.
Innovation Solution
A controller for the internal combustion engine that executes a fuel cut-off process and increases the pressure in the intake passage downstream of the throttle valve before opening the recirculation valve, reducing the force required to open the valve and thus minimizing actuator size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the recirculation valve is opened during fuel cut-off process, then the exhaust gas recirculation function is achieved, but the large pressure difference requires a large actuator
Solution Approach 1:
The throttle valve is opened in advance before opening the recirculation valve during fuel cut-off process. This preliminary action increases the intake passage pressure, reducing the pressure difference that the actuator must overcome, thereby allowing a smaller actuator to be used while still achieving reliable exhaust gas recirculation
2Ease of operation
If the actuator opens the recirculation valve against large pressure difference, then the valve opens successfully, but the actuator force requirement increases
Solution Approach 1:
The throttle valve is opened beforehand to increase intake passage pressure before the recirculation valve opening operation. This reduces the opposing pressure force, making it easier for the actuator to open the recirculation valve with less force requirement
3Reliability
If fuel injection is stopped during the process, then the fuel cut-off function is achieved, but the pressure difference across the recirculation valve increases
Solution Approach 1:
The throttle valve is opened in advance of the fuel cut-off process to compensate for the upcoming pressure drop. This maintains a more stable pressure difference across the recirculation valve, preventing excessive pressure differential that would require larger actuators
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
This approach reduces the size of the actuator needed to open the recirculation valve during fuel cut-off by decreasing the pressure difference across the valve, preventing actuator enlargement and enhancing operational efficiency.
Implementation Method 1
execute a pressure increase process that increases pressure of the portion of the intake passage at the downstream side of the throttle valve before opening the recirculation valve
Data Source
AI summary
There is provided a controller for an internal combustion engine that includes an exhaust gas recirculation device. The exhaust gas recirculation device includes an exhaust gas recirculation passage, which connects a portion of the intake passage located at a downstream side of the throttle valve with an exhaust passage, a recirculation valve, which opens and closes the exhaust gas recirculation passage, and an actuator, which drives and opens the recirculation valve. The controller includes a processor configured to execute a fuel cut-off process that stops fuel injection from the fuel injection valve, to open the recirculation valve when the fuel cut-off process is executed, and to execute a pressure increase process that increases pressure of the portion of the intake passage at the downstream side of the throttle valve before opening the recirculation valve.