Electronic Throttle Control for Engine Misfire Torque Fluctuations
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Solution Overview
Problem
Conventional misfire detection devices in internal combustion engines, such as those in motorcycles, cause abrupt torque changes and drivability degradation when fuel cut or throttle adjustments are made, especially due to detection errors or interference, leading to shock and decreased performance.
Innovation Solution
A control device and method that includes a misfire detection unit and electronic throttles for each cylinder, where the throttle opening degree is gradually decreased when a misfire is detected, mitigating abrupt torque changes and allowing for smoother engine operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fuel cut or throttle opening degree is immediately changed when misfire is detected, then catalyst protection is improved, but drivability deteriorates due to abrupt torque changes
Solution Approach 1:
The throttle opening degree limited value is made dynamically adjustable based on vehicle speed. At low vehicle speeds, a stricter limitation is applied to protect the catalyst, while at high vehicle speeds, the limitation is relaxed to maintain drivability. This dynamic adjustment resolves the contradiction by adapting the control strategy to operating conditions.
Solution Approach 2:
The invention changes the parameter of throttle opening degree limitation based on detection results and vehicle speed. When misfire is detected at low speeds, the throttle opening degree is strictly limited. When the same condition occurs at high speeds, the limitation is relaxed. This parameter change approach allows the system to protect the catalyst when necessary while maintaining drivability when possible.
2Ease of operation
If throttle opening degree is gradually decreased when misfire is detected, then drivability is maintained, but catalyst protection may be compromised
Solution Approach 1:
The system adjusts the throttle opening degree limitation parameter based on vehicle speed. At low speeds, a strict limitation is applied to ensure catalyst protection, while at high speeds, the limitation is relaxed to maintain drivability. This conditional parameter change resolves the contradiction by applying different control strategies based on operating conditions.
Solution Approach 2:
The invention applies different control qualities to different operating conditions. For low-speed misfire detection, strict catalyst protection is applied. For high-speed misfire detection, more lenient control is applied to maintain drivability. This local quality approach allows the system to optimize for the appropriate goal based on the specific operating context.
3Measurement precision
If detection sensitivity is increased to accurately detect misfire state, then misfire detection accuracy is improved, but false detection increases leading to unnecessary fuel cut
Solution Approach 1:
The system changes the control parameter (throttle opening degree limitation) based on vehicle speed while maintaining the same misfire detection criteria. This allows the system to respond appropriately to detection results without changing the detection sensitivity itself, thereby avoiding false detections while maintaining accurate misfire detection.
Solution Approach 2:
The control response is made dynamic based on vehicle speed rather than changing detection sensitivity. The same detection accuracy is maintained, but the control action varies dynamically with operating conditions, preventing unnecessary fuel cuts due to false detections while maintaining accurate misfire detection capability.
Data Source
AI summary
The control device for an internal combustion engine including a plurality of cylinders includes: a misfire detection unit for detecting a misfire state for each of the plurality of cylinders; a plurality of electronic throttles each provided on an intake pipe corresponding to each of the plurality of cylinders, for adjusting an intake air amount taken into each cylinder by way of a throttle opening degree; and a throttle opening degree control unit for controlling the throttle opening degree of each of the plurality of electronic throttles. When the misfire detection unit detects the misfire state in any one of the plurality of cylinders, the throttle opening degree control unit decreases a limited value of the throttle opening degree of the cylinder in the misfire state as time elapses.