Fuel Injection Timing Control for Catalyst Light-Off
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Solution Overview
Problem
Internal combustion engines face challenges in efficiently heating a catalyst to its light-off temperature due to the current methods of controlling fuel injection timing, which can result in increased particulate emissions and prolonged catalyst heating times when spark ignition timing is retarded.
Innovation Solution
A system and method that determine fuel injection timing based on spark ignition timing, offsetting fuel injection by a predetermined amount when spark ignition timing exceeds a certain limit to prevent fuel injection at top dead center, thereby increasing exhaust gas temperature and reducing catalyst heating time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If fuel injection timing is controlled using conventional methods, then engine operation is maintained, but catalyst heating time is prolonged and particulate emissions increase
Solution Approach 1:
The patent changes the fuel injection timing parameter dynamically based on spark ignition timing conditions. When spark timing is retarded beyond a predetermined limit, the system adjusts fuel injection timing to occur later in the compression stroke, thereby increasing exhaust gas temperature and accelerating catalyst heating while controlling emissions.
Solution Approach 2:
The system continuously monitors spark ignition timing and provides feedback to the fuel injection control system. Based on this feedback, the fuel injection timing is adjusted in real-time to maintain optimal exhaust gas temperature for catalyst heating, preventing prolonged heating times and excessive particulate emissions.
2Temperature
If spark ignition timing is retarded to heat catalyst, then catalyst heating is accelerated, but fuel injection at top dead center increases particulate emissions
Solution Approach 1:
The system determines in advance whether spark ignition timing will exceed the predetermined limit before fuel injection occurs. When retardation is detected, the fuel injection timing is pre-adjusted to occur after the piston passes top dead center, preventing fuel injection at the harmful timing while still achieving the desired exhaust gas temperature rise for catalyst heating.
Solution Approach 2:
The fuel injection timing is made dynamic rather than fixed, adjusting automatically based on the detected spark ignition timing conditions. The system transitions between different fuel injection timing strategies depending on whether spark timing is within or beyond the predetermined limit, optimizing both catalyst heating and emissions control.
3Productivity
If fuel injection timing is offset when spark timing exceeds limit, then catalyst heating is improved, but injection timing control complexity increases
Solution Approach 1:
The control system uses the spark ignition timing information already available in the engine control unit to automatically adjust fuel injection timing. The system serves itself by utilizing existing sensors and control mechanisms rather than requiring additional complex hardware, thereby improving catalyst heating rate while limiting the increase in overall system complexity.
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 effectively reduces the time required to heat the catalyst to its light-off temperature, minimizing particulate emissions and improving engine efficiency by synchronizing fuel injection with spark timing.
Implementation Method 1
The spark control module controls a spark plug to generate spark in a cylinder of an engine at the first crank angle
Implementation Method 2
The fuel control module controls a fuel injector to deliver fuel to the cylinder at the second crank angle
Implementation Method 3
Internal combustion engines combust an air and fuel mixture within cylinders to drive pistons, which produces drive torque
Implementation Method 4
exhaust gas produced by the engine may be used to heat a catalyst in an exhaust system of the engine to its light-off temperature
Data Source
AI summary
A system according to the principles of the present disclosure includes an ignition timing determination module, an injection timing determination module, a spark control module, and a fuel control module. The ignition timing determination module determines a first crank angle. The injection timing determination module selectively determines a second crank angle based on the first crank angle. The spark control module controls a spark plug to generate spark in a cylinder of an engine at the first crank angle. The fuel control module controls a fuel injector to deliver fuel to the cylinder at the second crank angle.