Ethanol Cold Start Control Using Injector Heater Pre-Injection
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Solution Overview
Problem
Flexible fuel vehicles (FFVs) using ethanol fuel face challenges with low vapor pressure and poor startability, particularly during cold starts, as existing solutions like auxiliary fuel tanks and fuel heating methods are either costly, increase safety risks, or fail to effectively reduce heat loss and achieve rapid startability.
Innovation Solution
An engine starting control method that uses an injector with a heating function to preheat fuel before main injection, performing pre-injection near Top Dead Center and controlling throttle opening to optimize fuel vaporization and reduce fuel consumption, allowing for stable and rapid cold starts with less fuel and energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an auxiliary fuel tank is added to store cold start fuel, then cold startability is improved, but device complexity and safety risks increase
Solution Approach 1:
The invention extracts the cold start fuel supply function from the main fuel tank system and implements it through the existing fuel pump and injector infrastructure. The fuel pump is controlled to operate in a first mode during cold start conditions, drawing fuel from the main tank but delivering it through the existing fuel rail and injector system, thereby achieving cold start improvement without adding an auxiliary tank or complex dual-tank infrastructure.
Solution Approach 2:
The existing fuel pump is given multi-functionality by implementing two operational modes: a first mode for cold start conditions and a second mode for normal operation. The same fuel pump serves both cold start and regular fueling needs, eliminating the requirement for separate auxiliary storage while maintaining improved cold startability through controlled fuel delivery characteristics.
2Reliability
If fuel is heated to improve vaporization, then startability is improved, but heat loss increases and target temperature is difficult to achieve
Solution Approach 1:
The system performs preliminary heating of the fuel during a pre-heating period before the actual cold start injection. The fuel pump operates in the first mode during this pre-heating phase, allowing the fuel to warm up in the fuel rail and lines before being injected into the cylinder. This preliminary action reduces the temperature differential and minimizes heat loss during the critical injection phase.
Solution Approach 2:
The fuel itself serves as the heating medium for the fuel delivery system. By circulating fuel through the fuel pump and fuel rail during the first mode operation, the system uses the fuel's own thermal capacity to warm the delivery infrastructure, eliminating the need for external heating elements and reducing energy loss to the environment.
3Reliability
If fuel heating time is extended to reduce heat loss, then startability improves, but starting time increases
Solution Approach 1:
The system dynamically adjusts the fuel pump operating parameters between two distinct modes. During cold start, the first mode parameters are used to optimize fuel delivery for warming and vaporization. Once the fuel reaches adequate temperature, the system transitions to the second mode for normal operation. This parameter switching allows controlled, efficient heating without excessive time extension.
Solution Approach 2:
The fuel pump operates in periodic cycles, alternating between the first mode (cold start/heating mode) and the second mode (normal operation mode). During the first mode period, fuel is delivered to warm the system; after a predetermined time interval, the system transitions to the second mode. This periodic action achieves necessary heating while limiting total heating time and enabling rapid transition to normal operation.
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 method enables stable and rapid engine starting during cold winter conditions with ethanol fuel, reducing fuel consumption and energy use while minimizing harmful emissions, and improving startability with reduced heat loss and safety risks.
Implementation Method 1
the ECU supplies power to the heater disposed in the fuel pump to heat the fuel
Data Source
AI summary
Disclosed is an engine starting control method for a flexible fuel vehicle (FFV) of supplying the heated fuel to the engine by heating an injector heater during cranking when it is determined that cranking condition and fuel heating condition are satisfied at the time of starting the vehicle having a starting auxiliary device for cranking the engine of FFV and a device for heating the fuel using the injector heater provided in an injector, wherein a pre-injection is auxiliary performed prior to a main injection during cold starting of the engine when the heating time of the injector heater exceeds a predetermined value, allowing stable starting with low fuel consumption at a time of cold starting an engine using ethanol fuel in winter.