Engine Control Apparatus Fuel Injection Threshold Adjustment
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Solution Overview
Problem
Conventional engine control systems trigger fail-safe processes at high vehicle speeds, leading to driver discomfort due to incorrect detection of fuel injection abnormalities, as they do not account for varying vehicle speeds when determining fuel injection deviations.
Innovation Solution
An engine control apparatus that adjusts the injection amount threshold based on vehicle speed-associated parameters, such as accelerator opening degree and engine rotational speed, to prevent false abnormality detections at high speeds, using multiple determination modes and thresholds to confirm abnormalities over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed injection amount threshold is used for abnormality detection regardless of vehicle speed, then fuel injection abnormalities can be detected at low vehicle speeds, but false abnormality detections occur at high vehicle speeds causing driver discomfort
Solution Approach 1:
The patent applies dynamics by making the injection amount threshold variable rather than fixed. The threshold is dynamically adjusted based on vehicle speed-associated parameters (accelerator opening degree and engine rotational speed). At high vehicle speeds, the threshold is increased to prevent false detections, while at low speeds, a lower threshold maintains detection sensitivity. This resolves the contradiction by adapting the detection criterion to operating conditions.
Solution Approach 2:
The patent changes the parameter of the injection amount threshold based on vehicle speed-associated parameters. Specifically, when the accelerator opening degree is large or engine rotational speed is high (indicating high vehicle speed), the injection amount threshold is set to a larger value. This parameter adjustment prevents false abnormality detections at high speeds while maintaining accurate detection at low speeds, thereby resolving the contradiction between detection accuracy and driver comfort.
2Object-affected harmful factors
If the injection amount threshold is set large to prevent false detections at high vehicle speed, then driver comfort is maintained, but the ability to detect actual abnormalities at low vehicle speed decreases
Solution Approach 1:
The patent uses dynamics to adjust the injection amount threshold according to vehicle operating conditions. Rather than using a uniformly large threshold, the system dynamically sets smaller thresholds at low vehicle speeds (when accelerator opening degree is small and engine rotational speed is low) to maintain detection sensitivity, and larger thresholds at high vehicle speeds to prevent false alerts. This resolves the contradiction by making the threshold adaptive to speed conditions.
Solution Approach 2:
The patent changes the injection amount threshold parameter based on vehicle speed-associated parameters. When the accelerator opening degree is small and engine rotational speed is low (indicating low vehicle speed), the threshold is set to a smaller value to ensure actual abnormalities are detected. This parameter adaptation resolves the contradiction between maintaining driver comfort and preserving detection sensitivity across different operating conditions.
3Reliability
If fail-safe processes are triggered frequently to ensure safety, then engine reliability is improved, but driver comfort deteriorates due to excessive warnings and fuel injection limitations
Solution Approach 1:
The patent changes the injection amount threshold parameter based on vehicle speed-associated parameters to reduce unnecessary fail-safe triggers. By setting larger thresholds at high vehicle speeds, the system prevents false abnormality detections that would otherwise trigger unnecessary warnings and fuel injection limitations. This resolves the contradiction by making safety countermeasures more selective, maintaining engine reliability while reducing driver discomfort from excessive warnings.
Data Source
AI summary
An engine control apparatus is equipped with a fuel injection amount computation unit, a determination process unit, and an engine abnormality process unit. The determination process unit determines, based on a deviation between a command injection amount and a monitoring injection amount, whether or not there is an abnormality in fuel injection control. An injection amount threshold, which is used to make a determination on an abnormality in fuel injection control, is set larger based on a vehicle speed-associated parameter when the vehicle speed-associated parameter is a value corresponding to a case where a vehicle speed is high than when the vehicle speed-associated parameter is a value corresponding to a case where the vehicle speed is low.