Work Vehicle Engine Control Abnormality Detection
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Solution Overview
Problem
Conventional work vehicles fail to adjust fuel injection appropriately when abnormalities occur in the intake passage, leading to excessive engine rotational speed due to misdetected intake pressure, which can persist during normal operations.
Innovation Solution
Incorporating an abnormality treating means that detects high intake pressure and engine rotational speed, along with the throttle valve's state, to initiate an emergency stop and report the issue to the driver, ensuring the engine is stopped and fuel supply is halted.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the engine controlling means continuously adjusts fuel injection amount based on detected intake pressure and engine rotational speed, then the target air-fuel ratio can be achieved under normal conditions, but excessive rise in engine rotational speed occurs when abnormality develops in the intake passage
Solution Approach 1:
The system introduces a feedback mechanism where the abnormality detecting means continuously monitors intake pressure and throttle valve opening degree, compares actual values with expected values, and triggers engine stopping treatment when abnormality is detected. This feedback loop prevents the harmful effect of excessive engine rotational speed by detecting the discrepancy between detected intake pressure and throttle valve state, thereby resolving the contradiction between maintaining reliable engine control and preventing harmful effects during abnormalities
Solution Approach 2:
The abnormality detecting means acts as an intermediary between the engine controlling means and the throttle valve. It monitors the relationship between throttle valve opening degree and intake pressure, and when abnormality is detected (such as intake pipe breakage), it triggers the abnormality treating means to stop the engine. This intermediary function resolves the contradiction by preventing the harmful feedback loop that would otherwise occur when the engine controlling means continuously adjusts fuel injection based on erroneous intake pressure readings
2Measurement precision
If the intake pressure detecting means detects high intake pressure and the engine controlling means adjusts fuel injection amount accordingly, then the target air-fuel ratio is achieved, but the abnormality causing excessive intake pressure rise is not addressed
Solution Approach 1:
The abnormality detecting means implements a feedback mechanism that monitors not only intake pressure but also the relationship between throttle valve opening degree and intake pressure. When the detected intake pressure does not correspond to the throttle valve opening degree (indicating abnormality), the system triggers engine stopping treatment. This feedback approach resolves the contradiction by using measurement precision to detect abnormalities and prevent unsafe engine operation
Solution Approach 2:
The system performs preliminary detection of abnormalities by monitoring the relationship between throttle valve opening degree and intake pressure before excessive engine rotational speed occurs. When abnormality is detected (such as intake pipe breakage), the abnormality treating means stops the engine in advance, preventing the harmful effect of continued operation with incorrect air-fuel ratio. This preliminary action resolves the contradiction by using accurate measurement to prevent safety issues before they occur
Data Source
AI summary
There are provided an intake pressure detecting means for detecting an intake pressure on more downstream side than a throttle valve in an intake passage to an engine, a rotational speed detecting means for detecting a rotational speed of an engine, an engine controlling means for controlling the engine to arrive at a target air-fuel ratio corresponding to the detected intake pressure and the detected engine rotational speed and an abnormality treating means for executing an engine stopping treatment to stop the engine if an intake pressure higher than a set pressure has been detected and an engine rotational speed higher than a set rotational speed has been detected, when an opening degree state detecting means detects that the throttle valve is under a fully closed or substantially fully closed state.