Engine Control Apparatus Switching Between Isochronous and Droop Control
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Solution Overview
Problem
Existing engine control methods, such as isochronous and droop control, cause driver discomfort due to sudden acceleration/deceleration and slow response, and mechanical governors risk engine stalling or damage from sudden load changes.
Innovation Solution
An engine control apparatus that automatically switches between droop control and isochronous control methods based on engine load and operation state, using an electronic throttle to adjust intake air amount and rotation speed, thereby preventing sudden changes and maintaining optimal rotation speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If isochronous control is used to maintain target rotation speed, then rotation speed stability is improved, but sudden acceleration/deceleration occurs causing driver discomfort
Solution Approach 1:
The patent applies dynamics by making the control method adjustable based on operating conditions. The control apparatus switches between isochronous control and droop control depending on the accelerator operation amount, allowing the system to adapt its behavior dynamically. This resolves the contradiction by using isochronous control for stability during steady-state operation while switching to droop control for comfort during acceleration/deceleration events.
Solution Approach 2:
The patent changes the control parameter (control method) based on the accelerator operation amount. When the accelerator operation amount exceeds a threshold, the system switches from isochronous to droop control. This parameter change allows the system to maintain rotation speed stability during normal operation while reducing driver discomfort during dynamic acceleration/deceleration by allowing controlled rotation speed variations.
2Object-affected harmful factors
If droop control is used to reduce driver discomfort, then driver comfort is improved, but response during acceleration/deceleration becomes slow causing driver stress
Solution Approach 1:
The system dynamically switches control methods based on the accelerator operation amount. During steady-state operation, isochronous control provides fast response. When acceleration/deceleration is detected (accelerator operation amount exceeds threshold), the system switches to droop control to reduce driver discomfort. This dynamic adaptation resolves the contradiction by providing fast response when needed and comfort when needed.
Solution Approach 2:
The patent segments the operating range into different zones based on accelerator operation amount. One zone (low accelerator operation) uses isochronous control for fast response, while another zone (high accelerator operation) uses droop control for comfort. This segmentation allows each control method to operate in its optimal range, resolving the contradiction between response speed and driver comfort.
3Ease of manufacture
If mechanical governor is used to control engine load, then load control is simplified, but engine stalling or damage occurs from sudden load changes
Solution Approach 1:
The patent replaces the mechanical governor with an electronic control system that uses an electronic throttle and control apparatus. This substitution maintains the simplicity of load control while adding the capability to detect sudden load changes and switch control methods accordingly. The electronic system can prevent engine stalling and damage by detecting abnormal conditions and adjusting throttle position before damage occurs.
Solution Approach 2:
The control apparatus continuously monitors engine parameters including rotation speed and load, and uses this feedback to determine when to switch between control methods. When sudden load changes are detected, the system adjusts the throttle position to prevent engine stalling or over-revolution. This feedback mechanism maintains the simplicity of load control while significantly improving engine reliability by preventing abnormal operating conditions.
4Reliability
If over revolution control is activated to prevent engine damage, then engine protection is improved, but sudden rotation speed change occurs causing driver discomfort
Solution Approach 1:
The control apparatus performs preliminary action by continuously monitoring engine parameters and preparing to switch control methods before over-revolution or stalling occurs. When the accelerator operation amount exceeds the threshold, the system is already positioned to switch to droop control, which allows gradual rotation speed adjustment. This preliminary preparation enables smooth engine protection without sudden rotation changes, resolving the contradiction between engine protection and driver comfort.
Data Source
AI summary
When an accelerator operation amount is 0, a throttle actuator is controlled by means of isochronous control by using a second throttle operation amount (θtps2) for the isochronous control, and, on the other hand, when the accelerator operation amount is not 0, the throttle actuator is controlled by means of droop control by using a first throttle operation amount (θtps1) for the droop control. When an engine rotation speed is equal to or lower than a LOW rotation speed, larger one of the first and second throttle operation amounts (θtps1 and θtps2) is used, and when the engine rotation speed is equal to or higher than a HIGH rotation speed, smaller one of the first and second throttle operation amounts (θtps1 and θtps2) is used, to thereby control the throttle actuator by means of the isochronous control.