SIDI Cold Start Control via Throttle and Injection Switching
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Solution Overview
Problem
Spark ignition direct injection (SIDI) engines face challenges in starting at temperatures below the flash point of the fuel, as the fuel cannot vaporize, leading to difficulties in engine startup without the use of auxiliary devices that increase vehicle cost.
Innovation Solution
A cold start control system that includes a starter control module, mode setting module, throttle control module, and fuel control module, which initiates engine cranking, sets a coldstart mode, selectively closes the throttle valve, and disables direct fuel injection during cranking to facilitate engine startup at low temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If direct fuel injection is used in SIDI engines, then fuel economy and power are improved, but engine startup reliability deteriorates at temperatures below the fuel's flash point
Solution Approach 1:
The system changes the operating parameters of the fuel injection system by disabling direct injection during cold cranking and switching to port fuel injection. This parameter change allows the engine to start reliably at low temperatures while maintaining the benefits of direct injection during normal operation for improved fuel economy and power.
Solution Approach 2:
The fuel injection system dynamically switches between direct injection and port fuel injection modes based on engine temperature conditions. The control system monitors coolant temperature and automatically selects the appropriate injection mode, making the system adaptive to different operating conditions.
2Reliability
If auxiliary devices are added to enable cold startup, then engine startup reliability is improved, but device complexity and cost increase
Solution Approach 1:
The existing fuel injection system is made multi-functional by enabling it to operate in two modes: direct injection for normal operation and port fuel injection for cold startup. This eliminates the need for separate auxiliary devices while maintaining cold startup capability, reducing system complexity and cost.
Solution Approach 2:
The control system automatically detects cold conditions and switches the fuel injection mode without requiring external auxiliary devices. The system serves itself by using its own existing components (fuel injectors, control module) to resolve the cold startup problem, avoiding additional hardware.
3Quantity of substance
If throttle valve is kept open during cranking, then air flow to cylinders is improved, but fuel vaporization deteriorates at low temperatures
Solution Approach 1:
The control system changes the throttle valve position parameter during cold cranking to a more closed position compared to normal operation. This parameter change increases manifold pressure and temperature, improving fuel vaporization while the port fuel injection method ensures adequate air-fuel mixing despite reduced airflow.
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 SIDI engine startup at temperatures below the fuel's flash point without auxiliary devices, improving starting reliability while maintaining cost-effectiveness by controlling throttle and fuel injection to enhance fuel vaporization.
Implementation Method 1
a throttle valve to be biased to a predetermined open position when the SIDI engine is off and, in response to the setting of the mode to the coldstart mode, selectively closes the throttle valve relative to the predetermined open position during the cranking
Implementation Method 2
A fuel injection system for an SIDI engine is operated at high pressure to inject fuel directly into combustion chambers
Implementation Method 3
A fuel pump for supplying the fuel to a fuel rail at high pressure is mechanically driven by the engine
Implementation Method 4
Internal combustion engines combust air and fuel within cylinders to produce drive torque
Implementation Method 5
Enables SIDI engine startup at temperatures below the fuel's flash point without auxiliary devices, improving starting reliability while maintaining cost-effectiveness by controlling throttle and fuel injection to enhance fuel vaporization
Data Source
AI summary
A control system includes a starter control module, a mode setting module, a throttle control module, and a fuel control module. The starter control module initiates cranking of a spark ignition direct injection (SIDI) engine in response to user actuation of an ignition switch. The mode setting module sets a mode of operation to a coldstart mode when an engine coolant temperature is less than a predetermined temperature during the cranking. The throttle control module allows a throttle valve to be biased to a predetermined open position when the SIDI engine is off and, in response to the setting of the mode to the coldstart mode, selectively closes the throttle valve relative to the predetermined open position during the cranking. The fuel control module, in response to the setting of the mode to the coldstart mode, disables direct injection of fuel for a first combustion event during the cranking.