Motor Grader Engine Speed Control for Fuel Efficiency
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Solution Overview
Problem
Motor graders face inefficient fuel consumption during low-speed operations due to excessive engine torque, and existing solutions fail to improve fuel efficiency without reducing maximum speed during out-of-service traveling.
Innovation Solution
An engine speed control device that sets upper limit engine speeds differently for working and out-of-service modes, allowing earlier shifting to higher speed stages during work and maintaining high speeds during out-of-service travel, while avoiding torque reduction and engine stall phenomena.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the engine speed is limited to a low upper limit during low speed stages to improve fuel efficiency, then fuel consumption is reduced, but the maximum speed during out-of-service traveling is reduced
Solution Approach 1:
The patent applies dynamics by making the upper limit engine speed adjustable based on the selected speed stage. When a low speed stage is selected, a first (lower) upper limit engine speed is set to improve fuel efficiency. When a high speed stage is selected, a second (higher) upper limit engine speed is set to maintain maximum traveling speed. This dynamic adjustment resolves the contradiction between fuel efficiency and maximum speed capability.
Solution Approach 2:
The patent changes the parameter of upper limit engine speed based on the selected speed stage. By setting different upper limit engine speed values (first upper limit for low speed stages, second upper limit for high speed stages), the system optimizes fuel consumption during working conditions while preserving maximum speed capability during out-of-service traveling conditions.
2Use of energy by moving object
If the upper limit engine speed is set low during low speed stages, then fuel efficiency improves, but the engine torque becomes excessive relative to load
Solution Approach 1:
The patent changes the upper limit engine speed parameter based on operating conditions. During low speed stages, a lower first upper limit engine speed is applied to improve fuel efficiency. The system accepts that engine torque may be excessive relative to load in this mode, prioritizing fuel efficiency for working conditions where the load is relatively light.
3Use of energy by moving object
If the maximum engine speed is limited in the maximum speed stage, then fuel consumption is reduced, but travel speed is reduced during out-of-service traveling
Solution Approach 1:
The patent dynamically adjusts the upper limit engine speed based on the selected speed stage. When the maximum speed stage is selected for out-of-service traveling, the system sets a higher second upper limit engine speed to maintain travel speed. When lower speed stages are selected for working conditions, a lower first upper limit engine speed is set to reduce fuel consumption. This resolves the contradiction by making the limitation conditional on the operating mode.
Data Source
AI summary
An engine speed control device is adapted to control a motor grader including a transmission with a plurality of manually shiftable low speed stages and at least one high speed stage, the transmission being configured to switch between a manual mode for manually selecting one of all the speed stages and an automatic shifting mode for automatically shifting a predetermined speed stage and higher. The engine speed control device includes an upper limit engine speed control unit configured to set an upper limit engine speed to be an out-of-service travelling-use upper limit engine speed at the at least one high speed stage, and set the upper limit engine speed to be a working-use upper limit engine speed at any one of the low speed stages, the working-use upper limit engine speed being lower than the out-of-service travelling-use upper limit engine speed.