Fuel Pressure Sensor Diagnosis Using Cumulative Warm-Up Parameter
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In hybrid vehicles and motor vehicles with idling stop functions, the temperature of the fuel supply pipe may be lower than the full warm-up determination temperature during key switch off-operations, leading to inappropriate abnormality diagnosis of the fuel pressure sensor due to intermittent engine operation and cooling effects from wind or idling stop mechanisms.
Innovation Solution
A motor vehicle configuration that includes an engine with an in-cylinder injection valve, a fuel supply device, a fuel pressure sensor, and a control device that increments a warm-up determination parameter based on engine operation time and decrements it based on vehicle speed and ambient temperature after engine stop, ensuring appropriate temperature reflection for abnormality diagnosis of the fuel pressure sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the engine operates intermittently (hybrid vehicle or idling stop function), then fuel economy is improved, but the fuel supply pipe temperature becomes insufficient leading to inappropriate fuel pressure sensor diagnosis
Solution Approach 1:
The patent changes the parameter used for warm-up determination from a simple temperature threshold to a cumulative operation time parameter. The control device determines warm-up based on whether the engine has operated for a predetermined time or more, rather than checking if the fuel supply pipe temperature exceeds a fixed threshold. This parameter change allows accurate diagnosis timing determination even when the engine operates intermittently and the fuel supply pipe temperature remains low.
2Object-affected harmful factors
If the engine is cooled by running wind or idling stop mechanism, then cooling effect is achieved, but the fuel supply pipe temperature drops below full warm-up determination temperature causing inappropriate diagnosis
Solution Approach 1:
The patent changes the warm-up determination parameter from temperature-based to time-based. By using cumulative engine operation time as the determination criterion, the system can accurately identify appropriate diagnosis timing even when the fuel supply pipe temperature is reduced by cooling effects from running wind or idling stop mechanisms.
3Ease of operation
If abnormality diagnosis is performed based on temperature threshold, then simple determination is achieved, but inappropriate diagnosis occurs when fuel supply pipe temperature is insufficient
Solution Approach 1:
The patent changes the determination parameter from temperature (which varies with operating conditions) to operation time (which directly reflects engine warmth). This allows the control device to accurately determine when the engine and fuel supply pipe are sufficiently warm without complex temperature measurements, maintaining simplicity while improving diagnosis accuracy.
Data Source
AI summary
After a system-off state has continued for a preset, time period since a system-off operation, on satisfaction of abnormality diagnosis prerequisites including a condition that a warm-up determination parameter indicating a degree of warm-up of an engine at a system-off time is equal to or greater than a predetermined value, characteristic abnormality diagnosis is performed to determine whether a characteristic abnormality occurs in a fuel pressure sensor. For a time period from a system-on operation to a system-off operation, the warm-up determination parameter is incremented when the engine is in operation, while being decremented after satisfaction of a predetermined condition when the engine is not in operation.