Early Ignition Timing for High Alcohol Engine Cold Start
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Solution Overview
Problem
Internal combustion engines with high alcohol content fuels, such as E100, face difficulties in starting at low temperatures due to ethanol's high boiling point and low vapor pressure, leading to reduced cold starting capability and the need for additional fuel containers or preheating systems, which are costly and inefficient.
Innovation Solution
A method and device that sets an early ignition time point during the starting process, between 60° to 100° crank angle before the top dead center, and adjusts it based on rotational speed thresholds, eliminating the need for separate fuel tanks or preheating systems by optimizing combustion behavior and reducing fuel entry into the lubricating oil.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If high alcohol content fuel (E100) is used, then fuel flexibility and environmental performance are improved, but cold starting capability deteriorates due to high boiling point and low vapor pressure
Solution Approach 1:
The patent changes the ignition timing parameter to an early ignition time point (60°-100° crank angle before top dead center) during cold starting with high alcohol content fuel. This parameter adjustment compensates for the poor vaporization characteristics of ethanol at low temperatures, enabling reliable cold starting while maintaining fuel flexibility.
2Reliability
If additional fuel containers with starting fuel are installed, then cold starting capability is improved, but device complexity and maintenance cost increase
Solution Approach 1:
The patent extracts and eliminates the additional fuel container system by using a single fuel tank for both cold starting and normal operation. The early ignition timing control method replaces the need for separate starting fuel storage, reducing system complexity while maintaining cold starting reliability.
Solution Approach 2:
The single fuel tank serves multiple functions: storing fuel for cold starting and storing fuel for normal engine operation. The early ignition timing system enables the main fuel tank to universally support both cold starting and regular combustion requirements.
3Productivity
If traditional ignition timing is used with high alcohol fuel, then combustion efficiency is maintained under normal conditions, but cold starting time increases and fuel loss to lubricating oil increases
Solution Approach 1:
The patent applies preliminary action by setting the ignition timing to occur early (60°-100° before top dead center) during cold starting. This advance ignition allows the combustion process to begin earlier, compensating for delayed fuel vaporization and reducing overall starting time while preventing fuel from entering the lubricating oil.
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
Enables reliable engine starting at low temperatures with high ethanol content fuels without additional components, reducing starting time and improving combustion behavior while minimizing fuel in the lubricating oil.
Implementation Method 1
an early starting ignition time point ZZP_ST is set in a first time period beginning immediately after the activation of the starting process of the internal combustion engine, which starting ignition time point ZZP_ST lies in a range from 60° crank angle to 100° crank angle before the top dead center of a piston
Data Source
AI summary
A method and a corresponding device are disclosed for starting an internal combustion engine designed for alcohol or a high content of alcohol in a mixed alcohol-gasoline fuel, including setting an early starting ignition time point in a first time period beginning immediately after the activation of the starting process of the engine. The rotational speed of the internal combustion engine is monitored and the number of the cylinder working cycles is summed during the starting process and, upon exceeding a predetermined rotational speed threshold value, the number of those cylinder working cycles is summed in which there occurs a rotational speed increase greater than a predetermined threshold value. The number of the cylinder working cycles is compared with predetermined threshold values and, upon reaching or exceeding the threshold values, the ignition time point is shifted starting from the early ignition time point toward a late ignition time point.