Engine Idle Speed Display Smoothing Under Auxiliary Load Changes
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Solution Overview
Problem
The idle speed of an engine changes rapidly with variations in load from auxiliary equipment, leading to driver misunderstandings about engine instability in an idle state.
Innovation Solution
A vehicle system that includes an engine, auxiliary equipment, a display device, and a control device with an engine control unit, acquisition, change determination, calculation, and display control units to smooth the engine's idle speed and display it gradually, avoiding sudden changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the engine control unit adjusts the idle speed to match the target idle speed that changes with auxiliary equipment load, then the engine can maintain proper operating speed under varying loads, but the displayed idle speed fluctuates rapidly causing driver misunderstanding of engine instability
Solution Approach 1:
The patent introduces a tachometer indication value as an intermediary between the actual engine speed and the displayed speed to the driver. This intermediary smoothly transitions between different idle speed targets based on auxiliary equipment load changes, masking the rapid fluctuations while still reflecting the overall trend. The tachometer indication value acts as a buffer that prevents direct transmission of abrupt speed changes to the driver's perception.
Solution Approach 2:
The patent changes the parameter displayed to the driver from the raw actual idle speed to a processed tachometer indication value. This parameter transformation involves comparing the current idle speed target with the previous target and smoothly adjusting the indication value accordingly, rather than directly displaying the potentially fluctuating actual speed. This parameter change converts unstable raw data into stable displayed information.
2Loss of information
If the system displays the actual idle speed directly, then the driver sees the true engine speed, but rapid changes in auxiliary equipment load cause sudden speed variations that appear as engine instability
Solution Approach 1:
The tachometer indication value serves as an intermediary that preserves the essential information about engine speed while filtering out destabilizing fluctuations. Rather than completely masking the actual speed changes, the intermediary smoothly transitions between speed levels, maintaining informational accuracy while achieving visual stability for the driver.
3Productivity
If the engine responds quickly to auxiliary equipment load changes, then the engine maintains optimal performance, but the tachometer shows rapid speed changes that confuse the driver about engine stability
Solution Approach 1:
The patent transforms the rapid engine response parameter into a smoother display parameter. The tachometer indication value changes more gradually than the actual engine speed, creating a temporal decoupling between the fast engine response and the slower perceived response. This allows the engine to maintain high productivity while the driver perceives stable operation.
Data Source
AI summary
A vehicle includes: an engine; auxiliary equipment that is driven by the engine; a display device; and a control device. The control device includes: an engine control unit that controls the engine in such a manner that an actual idle speed of the engine in an idle state becomes a target idle speed that changes with a load of the auxiliary equipment on the engine; an acquisition unit that acquires the actual idle speed; a change determination unit that determines whether an accelerator operation amount is zero and the target idle speed is changing; a calculation unit that calculates a slowly changing idle speed obtained by smoothing the actual idle speed with a predetermined degree of smoothing when a determination of the change determination unit is affirmative; and a display control unit that displays the slowly changing idle speed on the display device.