Engine Control Apparatus EGR Diagnosis Fuel Injection
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Solution Overview
Problem
Existing engine control systems face challenges in accurately diagnosing EGR valve failures and adjusting fuel injection and ignition timing post-diagnosis, leading to potential misfires and sudden torque variations due to individual differences in EGR valves and deposit accumulation, resulting in inadequate correction and impaired drivability.
Innovation Solution
An engine control apparatus with a first and second fuel injection amount calculator, an EGR valve controller, and an ignition controller that adjusts fuel injection and ignition timing based on intake air and pressure data, using weight coefficients to gradually transition from a pressure-based to an air-flow meter-based control after EGR valve diagnosis, ensuring stable torque and preventing misfires.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fuel injection is restarted immediately after EGR valve diagnosis, then engine operation is restored quickly, but sudden torque variations and misfires occur due to inaccurate fuel injection amounts
Solution Approach 1:
The system performs preliminary actions by increasing the second weight coefficient and gradually varying weight coefficients before normal fuel injection resumes, preparing the fuel injection system to handle the transitional state after EGR diagnosis and prevent torque variations and misfires
2Reliability
If fuel injection amount is increased to prevent misfire after EGR diagnosis, then combustion stability is improved, but torque becomes excessive causing vehicle shock
Solution Approach 1:
The system dynamically adjusts the weight coefficients over time, transitioning from relying on intake pressure (second weight coefficient) to relying on air flow meter (first weight coefficient), allowing the fuel injection amount to be appropriately controlled to prevent both misfire and excessive torque
Solution Approach 2:
The system implements periodic action by gradually varying the weight coefficients over a predetermined period after EGR diagnosis, enabling smooth transition of fuel injection control strategy to maintain stable torque without causing vehicle shock
3Measurement precision
If air flow meter data is used for fuel injection control, then intake air amount measurement is accurate, but measurement is unreliable immediately after EGR valve diagnosis due to residual exhaust gas in intake pipe
Solution Approach 1:
The system uses intake pressure (second fuel injection amount) as an intermediary measurement method when air flow meter data is unreliable, allowing accurate fuel injection control during the transitional period after EGR diagnosis when residual exhaust gas affects air flow meter readings
Data Source
AI summary
An engine control apparatus includes first and second fuel injection amount calculators, a fuel injection controller, an EGR valve controller, and an EGR valve diagnosis unit. The first and second fuel injection amount calculators are configured to calculate first and second fuel injection amounts on the basis of a detected intake air amount and detected pressure in an intake pipe, respectively. The fuel injection controller is configured to control a fuel injection apparatus for an engine on the basis of a correction fuel injection amount that is a result of addition of the first and second fuel injection amounts respectively multiplied by first and second weight coefficients. When the fuel injection is restarted after diagnosis of the EGR valve carried out by the EGR valve diagnosis unit, the fuel injection controller increases the second weight coefficient, and thereafter gradually increases and reduces the first and second weight coefficients, respectively.