Fuel Pump Idling Control for Evaporated Fuel Management
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Solution Overview
Problem
Existing control devices for internal combustion engines that continuously drive the fuel pump during automatic stop increase the amount of evaporated fuel in the fuel tank, requiring a larger canister to adsorb the excess fuel, which is inefficient and costly.
Innovation Solution
A control device that includes a fuel pump, an automatic stop restarting device, a fuel pump control unit, and an idling determination unit, which determines if the fuel pump is in an idling state and performs automatic restart even when conditions are not met, allowing continuous fuel pump operation without increasing the canister size by managing fuel pressure and temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the feed pump is continuously driven during automatic stop of the internal combustion engine, then fuel pressure is maintained and startability is improved, but the temperature of fuel is raised and evaporated fuel accumulates in the canister
Solution Approach 1:
The feed pump is operated periodically rather than continuously during automatic stop. The pump runs intermittently to maintain fuel pressure while reducing cumulative heating, thereby decreasing evaporated fuel generation while still ensuring adequate fuel pressure for restart
Solution Approach 2:
The operating parameters of the feed pump are adjusted during automatic stop, including reducing duty cycle and monitoring fuel temperature. When fuel temperature approaches a predetermined threshold, the pump operation is modified to prevent excessive heating and evaporated fuel generation
2Stress or pressure
If the feed pump is continuously driven in the idling state during automatic stop, then fuel pressure is maintained, but fuel heated by driving heat is returned to the fuel tank and evaporated fuel increases
Solution Approach 1:
The system monitors fuel temperature and pump operating conditions during automatic stop. When the fuel pump is in an idling state and fuel temperature approaches the predetermined value, the control unit adjusts pump operation to prevent excessive heating. This feedback control reduces evaporated fuel generation while maintaining adequate fuel pressure through selective pump operation
3Quantity of substance
If a large-size canister is mounted to adsorb sufficient evaporated fuel, then evaporated fuel accumulation is managed, but device complexity and cost increase
Solution Approach 1:
The system performs preliminary control actions during automatic stop to prevent excessive evaporated fuel generation before it occurs. By monitoring fuel temperature and adjusting feed pump operation in advance, the system prevents the need for a large canister, as evaporated fuel generation is kept within manageable limits through proactive temperature control
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 continuous fuel pump operation during automatic stop without enlarging the canister, effectively managing evaporated fuel and maintaining engine startability by accurately determining the idling state of the fuel pump, thus reducing the need for a larger canister and improving fuel efficiency.
Implementation Method 1
a feed pump provided within the fuel tank... The high-pressure pump further boosts the pressure of fuel supplied from the feed pump
Implementation Method 2
a fuel supply path connecting the feed pump and the fuel injection device may be often provided with a relief valve that opens and returns the fuel to the fuel tank when the fuel pressure exceeds the predetermined pressure
Implementation Method 3
a large amount of evaporated fuel may accumulate in a canister... capable of adsorbing a sufficient amount of evaporated fuel
Implementation Method 4
the temperature of fuel in the tank is raised due to driving heat of the feed pump
Data Source
AI summary
A control device for internal combustion engine capable of continuously driving a feed pump during automatic stop of the internal combustion engine without increasing the size of a canister is provided. The control device include a fuel supply pump supplying fuel within a fuel tank to a fuel injection device, an automatic stop restarting control unit performing automatic stop of the engine during operation according to vehicle state and then performs automatic restart of the engine during automatic stop, a fuel pump control unit driving the fuel supply pump during operation or automatic stop of the engine, and an idling determination unit determining whether the fuel supply pump is in an idling state. The automatic stop restarting control unit performs automatic restart when the idling determination unit determines that the fuel pump is in the idling state during automatic stop.