Vehicle Control Apparatus Torque Reduction Logic
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Solution Overview
Problem
Conventional vehicle control apparatuses reduce engine torque uniformly when both the accelerator and brake pedals are depressed, leading to hesitation and deteriorated drivability, especially in cases where the brake pedal is depressed unintentionally or with automatic transmissions without a clutch pedal.
Innovation Solution
A vehicle control apparatus with detection units for accelerator and brake pedals, determining intentional pedal operation to prevent unnecessary torque reduction, including a permission condition determination unit and an intention judgment determination unit to assess pedal operation patterns and frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fuel injection amount is uniformly reduced when both accelerator and brake pedals are depressed, then the engine torque is reduced, but the drivability deteriorates due to hesitation and unnecessary torque reduction
Solution Approach 1:
The patent applies local quality by differentiating the torque reduction control based on the specific driving situation. Instead of uniformly reducing torque in all cases where both pedals are depressed, the system selectively applies torque reduction only when the brake pedal depression exceeds a predetermined threshold, thereby maintaining drivability while ensuring reliable torque reduction when actually needed.
Solution Approach 2:
The patent changes the parameter of brake pedal depression amount from a binary state (depressed/not depressed) to a continuous measurement with a threshold comparison. By introducing a predetermined threshold value for brake pedal depression amount, the system dynamically adjusts whether torque reduction should be applied, resolving the contradiction between reliable torque reduction and maintaining drivability.
2Measurement precision
If the brake pedal depression threshold is set low to detect intentional braking, then torque reduction is applied frequently, but drivability deteriorates due to false detection of unintentional braking
Solution Approach 1:
The patent optimizes the parameter of brake pedal depression threshold to balance detection precision and drivability. By setting a predetermined threshold that filters out small unintentional depressions while capturing intentional braking, the system achieves accurate detection without excessive false positives that would harm drivability.
3Speed
If torque reduction is applied immediately when both pedals are depressed, then the control response is fast, but the drivability deteriorates due to sudden torque changes
Solution Approach 1:
The patent introduces a parameter threshold (predetermined brake pedal depression amount) that must be exceeded before torque reduction is applied. This threshold acts as a filter that prevents immediate torque reduction for minor pedal contacts, thereby maintaining smooth drivability while still providing fast response for genuine braking situations where the threshold is clearly exceeded.
Data Source
AI summary
When an ECU determines that an accelerator is “ON” and a brake is “ON”, the ECU determines whether or not the brake previously depressed is “OFF”. When the ECU determines that the brake previously depressed is “OFF” and that the vehicle is in the reduced speed state, the vehicle control apparatus is configured to execute an engine output reduction control process under the condition that the simultaneous depressions of the accelerator and brake pedals continues for less than 10 seconds and the vehicle speed is not less than 7 km/hr. When the simultaneous depressions of the accelerator and brake pedals continues for no less than 10 seconds, the ECU is configured to make an output reduction prohibition flag “ON” and not to execute the engine output reduction control process until a predetermined time elapses.