Engine Control Device Preventing Unintended Acceleration During Brake Override
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Solution Overview
Problem
Existing systems for internal combustion engines fail to maintain power output restriction when both the accelerator and brake pedals are depressed, as they remove the restriction if the accelerator pedal operation degree changes slightly, leading to unintended power output removal due to factors like pedal sticking or vibration.
Innovation Solution
A control system that restricts power output using a first and second restriction accelerator operation degree, with the second degree allowing increased throttle opening if the accelerator pedal is pressed harder, and removes the restriction when the brake pedal is released, ensuring safe deceleration and preventing unintended power output removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the power output restriction is removed when the accelerator pedal operation degree changes by a certain amount, then the system responds to intentional acceleration requests, but unintended power output removal occurs due to vibration or pedal sticking
Solution Approach 1:
The system dynamically adjusts the accelerator operation degree threshold based on vehicle speed. At low speeds, a smaller threshold is used to prevent unintended acceleration from vibration, while at high speeds, a larger threshold allows intentional acceleration requests to be recognized. This dynamic adaptation resolves the contradiction between responsiveness and stability.
Solution Approach 2:
The invention changes the parameter of accelerator operation degree threshold from a fixed value to a variable value that depends on vehicle speed. This parameter change allows the system to maintain appropriate sensitivity across different operating conditions, preventing unintended power removal while still responding to genuine acceleration requests.
2Reliability
If the power output restriction is maintained strictly during brake operation, then safety is ensured, but unintended acceleration is prevented even when the driver intends to accelerate
Solution Approach 1:
The system dynamically modifies the power output restriction behavior based on the rate of change of accelerator operation degree. When a rapid increase is detected, the system temporarily allows power output to exceed the standard restriction, enabling the driver to overcome brake drag and achieve intended acceleration, while maintaining strict restrictions during normal brake operation for safety.
Solution Approach 2:
The system applies preliminary anti-action by detecting rapid accelerator pedal depression before full acceleration is achieved. When such rapid change is detected during brake operation, the system preemptively allows power output to exceed restrictions, counteracting the brake drag effect before it prevents intended acceleration.
Data Source
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AI summary
[Summary] To accomplish such a control that a power output restriction of an internal combustion engine can be prevented from being removed upon a change in accelerator operation degree without an intention of a driver. For this purpose, a power output of the internal combustion engine is restricted to become a power output which is calculated by using a first restriction accelerator operation degree when a brake operation with a brake pedal is detected in addition to an accelerator pedal operation with an accelerator pedal, an opening degree of the throttle valve at the first restriction accelerator operation degree being set to be smaller than an opening degree at a fully opened state of the throttle valve; and the power output of the internal combustion engine is restricted to become a power output which is calculated by using a second restriction accelerator operation degree in place of the first restriction accelerator operation degree when an amount of change of the accelerator operation degree per unit time becomes larger than a preset certain value in a direction of depression of the accelerator pedal under a condition where the power output of the internal combustion engine is restricted by using the first restriction accelerator operation degree, the second restriction accelerator operation degree being larger than the first restriction accelerator operation degree, an opening degree of the throttle vale at the second restriction accelerator operation degree being set to be smaller than an opening degree at the fully opened state of the throttle valve.