Engine Control Apparatus for Recirculation Valve Diagnosis
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Solution Overview
Problem
Existing engine control systems face reduced accuracy in diagnosing closed-state malfunctions of compressor air recirculation valves, particularly in low turbocharging pressure ranges, due to decreased intake pulsation amplitude.
Innovation Solution
An engine control apparatus that includes a waste gate valve, a recirculation valve, pressure sensors, and airflow sensors, with a processor that opens the recirculation valve when the throttle valve is closed and diagnoses malfunctions based on air flow or pressure fluctuations, and adjusts the waste gate valve to maintain turbocharging pressure, thereby enhancing diagnostic accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the throttle valve is closed during turbocharging to diagnose recirculation valve malfunction, then the diagnosis can be performed, but the intake pulsation amplitude becomes too small in low turbocharging pressure range to ensure accurate diagnosis
Solution Approach 1:
The control apparatus changes the turbocharging pressure parameter by closing the waste gate valve to increase exhaust backpressure, which increases turbine rotational speed and compressor output pressure. This parameter change ensures that intake pulsation amplitude remains sufficient for accurate diagnosis even in originally low pressure ranges
Solution Approach 2:
The waste gate valve acts as an intermediary component to mediate the turbocharging pressure level. By adjusting the waste gate valve opening, the system can maintain appropriate pressure levels during diagnosis, ensuring reliable pulsation detection without requiring high initial 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
This solution allows for accurate diagnosis of closed-state malfunctions in compressor air recirculation valves even in low turbocharging pressure ranges by generating larger intake pulsation amplitudes, improving diagnostic reliability and expanding the diagnostic range.
Implementation Method 1
a compressor (21b) that compresses the intake air
Implementation Method 2
a turbine (21a) that rotates about a rotational axis extending in an axial direction of the exhaust passage
Implementation Method 3
a pressure sensor that measures a pressure at a downstream side of the compressor in the intake passage
Implementation Method 4
an airflow sensor that measures an amount of air flowing into the intake passage
Data Source
AI summary
A control apparatus includes a waste gate valve that opens and closes a passage bypassing a turbine in an exhaust passage of an engine, an air bypass valve that opens and closes a passage bypassing a compressor in an intake passage of the engine, a pressure measuring unit that measures a pressure at a downstream side of the compressor, an air-amount measuring unit that measures an amount of air flowing into the intake passage, an air-bypass-valve controller that opens the air bypass valve when a throttle valve in the intake passage is closed, a closed-state-malfunction diagnosing unit that diagnoses a closed-state malfunction of the air bypass valve based on a fluctuation in the measured amount of air when the throttle valve is closed, and a waste-gate-valve controller that closes the waste gate valve if the measured pressure is lower than a predetermined pressure when the throttle valve is closed.