Vehicle Control System for Flutter Operation Fuel Efficiency
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Solution Overview
Problem
Drivers with limited experience may inadvertently perform 'flutter operations' on the accelerator pedal, causing engine operation to deviate from minimum fuel consumption rates, leading to increased fuel consumption.
Innovation Solution
A control system for vehicles with continuously variable transmissions, featuring driving force parameter setting and control means, target value setting, and transmission control, which adjusts engine output based on accelerator pedal operation, incorporating operation modes to maintain constant target values and reduce fuel consumption even during flutter operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the control system calculates target engine rotational speed for minimum fuel consumption rate, then fuel consumption rate is reduced, but acceleration response deteriorates when accelerator pedal is rapidly depressed
Solution Approach 1:
The control system dynamically switches between minimum fuel consumption rate operation and good acceleration response operation based on accelerator pedal operation characteristics. When rapid depression is detected, the system transitions to acceleration-priority control; when steady operation is detected, it maintains fuel-efficient operation. This dynamic adaptation resolves the contradiction by allowing both operational modes within the same system.
Solution Approach 2:
The system changes operational parameters (target engine rotational speed, transmission gear ratio) based on detected accelerator pedal operation patterns. By monitoring the rate of change and magnitude of accelerator depression, the system adjusts parameters to prioritize either fuel efficiency or acceleration response, thereby resolving the contradiction between these two opposing objectives.
2Use of energy by moving object
If the control system performs minimum fuel consumption rate operation, then fuel consumption rate is reduced, but flutter operation of accelerator pedal causes deviation from optimal operation and deteriorates fuel consumption rate
Solution Approach 1:
The control system continuously monitors accelerator pedal operation and provides feedback to detect flutter operations. When flutter is detected (rapid small-amplitude oscillations), the system responds by adjusting control parameters to stabilize engine operation and prevent deviation from minimum fuel consumption rate operation. This feedback mechanism maintains both fuel efficiency and operational reliability.
Solution Approach 2:
The control system takes preliminary action by detecting flutter operations before they significantly deviate from optimal operation. By identifying the characteristic pattern of flutter (rapid small-amplitude accelerator movements), the system preemptively adjusts control parameters to counteract the destabilizing effect, thereby preventing fuel consumption rate deterioration before it occurs.
Data Source
AI summary
A demand driving force parameter indicative of a demand driving force of the engine is set based on the accelerator pedal operation amount, and a target value of an engine driving force control amount is set based on the demand driving force parameter. The engine driving force control amount is controlled so as to coincide with the target value. A target rotational speed of the engine is set based on the demand driving force parameter, and the continuously variable transmission is controlled so that the rotational speed of the engine coincides with the target rotational speed. One of a first operation mode and a second operation mode is selectable, wherein the fuel consumption rate in the second operation mode is less than the fuel consumption rate in the first operation mode. When the second operation mode is selected, the demand driving force parameter corresponding to the accelerator pedal operation amount is set to a value which is smaller than a value of the demand driving force parameter in the first operation mode, and the target value is calculated based on a first predetermined characteristic preliminarily set according to the engine rotational speed and the demand driving force parameter. The first predetermined characteristic is set so that the target value corresponding to the same engine rotational speed is substantially constant in a first predetermined range of the demand driving force parameter.