Direct Injection Pulse Scheduling for Cold-Start Emissions
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Solution Overview
Problem
Existing methods for direct injection of fuel into internal combustion engines, particularly during cold starts, result in high HC and NMHC emissions and fuel deposition on combustion chamber walls, leading to increased fuel consumption and emissions.
Innovation Solution
Implementing multiple partial fuel injections spaced apart in time, with a control unit determining the total injection mass and distributing it among the maximum possible number of partial injections to optimize fuel distribution and avoid wall deposition, using mass-based calculations to adjust for varying operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the number of partial injections is increased to improve mixture formation and reduce emissions, then HC, NMHC and soot emissions are reduced, but the complexity of the injection system and control increases
Solution Approach 1:
The total fuel injection is divided into multiple partial injections (typically 3-5 pulses) per combustion cycle, with each pulse delivering a portion of the total fuel mass. This segmentation improves mixture formation by creating multiple fuel-air mixing events rather than a single injection, thereby reducing incomplete combustion products like HC, NMHC and soot emissions while managing the complexity through systematic distribution of the total fuel mass.
Solution Approach 2:
The injection system dynamically adjusts the number of partial injections and the mass distribution among them based on operating conditions such as engine load, speed, and temperature. The control unit verifies the maximum possible number of partial injections and mass-distributes the total fuel mass accordingly, allowing the system to adapt to varying conditions and optimize emissions reduction while managing system complexity through intelligent control.
2Loss of energy
If multiple partial injections are used to reduce fuel deposition on chamber walls, then fuel consumption is optimized and emissions are reduced, but the control precision and verification of injection parameters become more difficult
Solution Approach 1:
The control unit continuously monitors injection parameters and verifies the maximum possible number of partial injections based on the critical mass threshold. The system uses feedback from sensors and pre-stored injection data to dynamically adjust the number and mass distribution of partial injections, ensuring optimal fuel atomization and mixture formation while preventing fuel deposition on chamber walls, thereby reducing fuel consumption and emissions.
Solution Approach 2:
The system changes injection parameters such as injection pressure, duration, and timing based on verified operating conditions. By mass-distributing the total fuel mass across a verified number of partial injections and adjusting parameters according to the critical mass threshold, the system optimizes fuel atomization and vaporization, reducing fuel deposition on cold chamber walls during cold starts and improving overall fuel efficiency.
3Object-generated harmful factors
If the number of partial injections is increased during cold starts, then mixture formation is improved and raw emissions are reduced, but the time required for complete fuel injection and combustion increases
Solution Approach 1:
The fuel injection is executed as periodic pulses within each combustion cycle, with a predetermined number of partial injections (e.g., 3-5 pulses) spaced at specific intervals. This periodic action ensures consistent fuel-air mixing during cold starts by creating multiple injection events per cycle, improving mixture formation and reducing raw emissions while maintaining a regular rhythm that prevents excessive time loss.
Solution Approach 2:
The control unit pre-verifies the maximum possible number of partial injections and pre-determines the mass distribution among them based on stored injection data and current operating conditions. By preparing the injection strategy in advance and mass-distributing the total fuel mass according to the critical mass threshold, the system ensures optimal mixture formation from the start of each cycle, reducing cold start emissions without delaying combustion.
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
Reduces fuel consumption and emissions, particularly HC and NMHC, by ensuring complete fuel combustion and minimizing wall deposition, especially during cold starts.
Implementation Method 1
fuel is injected directly into a combustion chamber of the internal combustion engine in a fuel injection device
Implementation Method 2
producing a fuel/air mixture taking into account a specified air-fuel ratio
Implementation Method 3
internal combustion engine operates cyclically
Implementation Method 4
incomplete combustion of the injected fuel leads to HC and NMHC emissions
Data Source
Figure 1
Figure 2~3
Figure 4A
AI summary
The invention relates to a method for operating an internal combustion engine, in particular a motor vehicle, in which fuel is injected directly into a combustion chamber of the internal combustion engine in a fuel injection device in a plurality of time-spaced partial injections per working cycle. The following steps are provided: determining the total injection mass (mTotal) per working cycle into the combustion chamber as a function of a power demand on the internal combustion engine as a function of an air mass supplied to the combustion chamber and producing a fuel/air mixture taking into account a predetermined air-fuel ratio; verifying a maximum possible number (n) of partial injections (TEn-max) per working cycle as a function of a critical mass threshold (mcrit) of a fuel injection valve assigned to the respective combustion chamber.where the fuel mass per partial injection (TEn) is not undercut, and the desired total fuel mass (mTotal) to be injected per operating cycle, defining a mass-based target injection number (TEn-target-MB) depending on the verified maximum possible number (n) of partial injections (TEn-max) and distributing the total fuel mass (mTotal) among the defined mass-based target injection number (TEn-target-MB), injecting the total fuel mass (mTotal) per operating cycle according to the mass-based target injection number (TEn-target-MB) with the fuel masses (m) distributed among the partial injections (TEn).