Engine Control System for Emissions During Idle
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Solution Overview
Problem
Vehicle exhaust after treatment systems, such as those containing catalysts and lean NOx traps, operate less efficiently at lower temperatures, leading to increased tailpipe emissions during engine idling and low load conditions, especially in diesel engines.
Innovation Solution
A method that predicts vehicle operating conditions using navigational and traffic data to adjust engine actuators, increasing exhaust gas temperature and feedgas emissions to maintain target emissions levels while minimizing fuel consumption, by retarding fuel injection timing and advancing exhaust valve opening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the engine is idled for longer periods during traffic stops, then the vehicle can maintain position and wait for traffic conditions to improve, but the exhaust after treatment system temperature decreases causing tailpipe emissions to increase
Solution Approach 1:
The system performs preliminary actions by adjusting engine actuators before the after treatment system temperature drops to harmful levels. The controller monitors temperature and proactively modifies fuel injection timing and valve timing to maintain temperature during extended idle periods, preventing emissions increases rather than reacting after they occur.
Solution Approach 2:
The system changes operating parameters of the engine actuators (fuel injection timing, intake valve timing, exhaust valve timing) to maintain exhaust gas temperature during idle conditions. By adjusting these parameters, the system optimizes combustion characteristics to generate sufficient heat to keep the after treatment system above its light-off temperature threshold.
2Reliability
If engine actuators are adjusted to increase exhaust gas temperature, then after treatment system efficiency is maintained, but fuel consumption increases
Solution Approach 1:
The system applies partial action by making minimal necessary adjustments to engine actuators only to the extent required to maintain after treatment system temperature. Rather than over-adjusting which would excessively increase fuel consumption, the controller applies just enough actuator modification to keep the system above the light-off temperature threshold.
Solution Approach 2:
The system uses feedback from temperature sensors monitoring the after treatment system to dynamically adjust engine actuator positions. The controller continuously compares actual temperature against target temperature ranges and modifies fuel injection and valve timing accordingly, creating a closed-loop control system that optimizes fuel efficiency while maintaining emissions control.
3Temperature
If fuel injection timing is retarded to increase exhaust gas temperature, then exhaust heat is increased, but engine fuel efficiency decreases
Solution Approach 1:
The system applies periodic adjustments to fuel injection timing rather than continuous retardation. During idle conditions requiring temperature maintenance, the injection timing is temporarily retarded; when temperature targets are met or driving conditions change, the timing returns to optimal efficiency positions. This periodic modulation reduces overall energy loss compared to sustained timing retardation.
Solution Approach 2:
The system changes fuel injection timing parameters dynamically based on real-time conditions. By retarding injection timing only when and where needed to maintain exhaust temperature, and returning to optimal timing otherwise, the system optimizes the trade-off between exhaust heat generation and fuel efficiency across varying operating conditions.
4Object-generated harmful factors
If engine actuators are adjusted to meet emissions requirements during idle conditions, then tailpipe emissions are reduced, but engine power and efficiency are compromised
Solution Approach 1:
The system applies local quality by making targeted actuator adjustments specific to idle and low-load conditions rather than uniformly across all operating modes. Different timing and injection strategies are applied locally to conditions where emissions control is most critical, while preserving engine power characteristics during high-load driving conditions.
Solution Approach 2:
The system uses dynamic actuator adjustment that adapts to changing operating conditions. Engine actuators are modified in real-time based on load, speed, and temperature conditions, allowing the system to maintain emissions control during idle while preserving engine power and efficiency during dynamic driving conditions where full power is needed.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces tailpipe emissions, maximizes fuel efficiency, and maintains after treatment system temperature, ensuring emissions compliance even during prolonged idling by pre-emptively adjusting engine operations based on expected conditions.
Implementation Method 1
An exhaust after treatment system may include a catalyst (e.g., an oxidation catalyst or a three-way catalyst), a selective catalytic reduction (SCR) catalyst, and/or lean NOx trap (LNT) for capturing NOx
Data Source
AI summary
Methods and systems for operating an engine that includes an after treatment system are described. In one example, traffic data and navigation system data are a basis for deciding whether or not to increase heat output of an engine to ensure operation of the after treatment system. In particular, one or more actuators may be adjusted to minimize fuel consumption and/or reduce feedgas emissions while generating sufficient heat to maintain after treatment system operation.