Starter-Generator Cold Start Load Control for Exhaust Heating
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Solution Overview
Problem
Existing technologies fail to effectively minimize tailpipe emissions and quickly bring the exhaust system of an internal combustion engine to operating temperature during a cold start.
Innovation Solution
A method involving a starter-generator to start the engine, disconnect it from the drive train, set an optimal operating point with increased torque and speed, generate electrical energy, and use it to heat the combustion air or cooling water, or supply it to consumers, while storing excess energy in a battery, to reduce emissions and accelerate the engine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the internal combustion engine is started and immediately connected to the drive train, then the vehicle can be driven without delay, but the exhaust system cannot be brought to operating temperature quickly enough and tailpipe emissions remain high
Solution Approach 1:
The engine is started and operated at an optimal operating point before being connected to the drive train. During this preliminary phase, the engine runs at conditions optimized for exhaust heating while the shutdown delay prevents vehicle movement, allowing the exhaust system to reach operating temperature in advance.
Solution Approach 2:
The engine's own operation during the shutdown delay period serves dual purposes: it provides the necessary heat to bring the exhaust system to operating temperature while simultaneously generating electrical energy through the starter-generator to power the vehicle's electrical systems.
2Object-generated harmful factors
If the engine is operated at optimal operating point with increased torque and speed, then exhaust system is heated faster and emissions are reduced, but the vehicle cannot be driven during this period due to shutdown delay
Solution Approach 1:
The engine is operated at the optimal operating point during a preliminary shutdown delay period before the vehicle is driven. This preliminary operation reduces emissions and heats the exhaust system, and the shutdown delay ensures the vehicle remains stationary during this optimized operation phase.
Solution Approach 2:
The system alternates between phases of optimized engine operation during shutdown delay and phases of normal vehicle operation. The periodic switching between these modes allows the engine to periodically operate at emission-reducing conditions while maintaining overall vehicle functionality.
3Productivity
If the starter-generator operates in generator mode for an extended period to generate electrical energy, then emissions are reduced and exhaust system is heated faster, but the vehicle startup is delayed
Solution Approach 1:
The starter-generator operates in generator mode during a preliminary shutdown delay period before the vehicle is driven. This preliminary energy generation occurs while the vehicle is stationary, allowing electrical energy to be produced without delaying the eventual vehicle startup.
Solution Approach 2:
The starter-generator continuously operates in generator mode during the shutdown delay period, maximizing electrical energy generation. This continuous operation during the otherwise wasted shutdown time converts a period of vehicle inactivity into a productive energy generation phase.
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 tailpipe emissions and accelerates the exhaust system to operating temperature, improving mixture formation and reducing CO and HC emissions during the cold start phase.
Implementation Method 1
Operating the starter-generator from the starting time in generator mode, for the predefined period of time, until an end time of the shutdown delay and generating electrical energy
Implementation Method 2
is fed to and consumed by an electrical heater, which converts the electrical energy into heat, which leads to an increase in the temperature of the cooling water in a cooling water system of the internal combustion engine
Implementation Method 3
is fed to and consumed by an electrically heated heat exchanger, which converts the electrical energy into heat, which leads to an increase in the temperature of the combustion air in a combustion air intake system of the internal combustion engine
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a method for reducing the emissions of an exhaust system (200) of an internal combustion engine (100) during cold start-up by increasing the load on the internal combustion engine (100) by means of a starter-generator (101).