Engine Controller Torque Limitation for Sub-Tank Fuel Supply
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Solution Overview
Problem
Existing engine controllers fail to prevent reduced drivability due to depletion of fuel in the sub-tank despite the presence of fuel in the main tank, leading to potential fuel supply shortages.
Innovation Solution
An engine controller with a fuel supplier system and processors that monitor the engine operation state to determine when the surplus fuel return to the jet pump is insufficient, calculates the remaining fuel based on vehicle travel state, accumulates fuel injection, and limits maximum torque when the sub-tank fuel is low, restoring the jet pump's function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the jet pump transfers fuel using venturi effect from the fuel tank to the sub-tank, then fuel supply to the engine is maintained, but when the engine operates in a range where surplus fuel return is small, the sub-tank fuel depletes despite fuel remaining in the fuel tank
Solution Approach 1:
The controller predicts future sub-tank fuel quantity based on current fuel level, engine operation range, and accumulated fuel injection amounts before actual depletion occurs. This preliminary prediction allows the system to take preventive action (torque limitation) to ensure fuel supply reliability before the sub-tank runs dry.
Solution Approach 2:
The controller continuously monitors engine operation state, calculates accumulated fuel injection amounts, and compares predicted sub-tank fuel quantity against thresholds. This feedback mechanism enables dynamic torque limitation adjustments to maintain fuel supply reliability while preventing sub-tank depletion.
2Reliability
If the controller limits maximum torque to preserve sub-tank fuel, then fuel supply reliability is maintained, but engine performance and productivity are reduced
Solution Approach 1:
The controller applies partial torque limitation only when predicted sub-tank fuel quantity falls below the threshold, rather than continuous limitation. This partial action maintains fuel supply reliability while minimizing impact on engine productivity during normal operation.
Solution Approach 2:
The torque limitation is dynamically adjusted based on real-time engine operation state and predicted fuel quantity. The controller modifies maximum torque limits adaptively, restricting torque only when necessary to preserve sub-tank fuel while allowing full performance when fuel levels are adequate.
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
Prevents reduced drivability by ensuring sufficient fuel supply to the sub-tank, maintaining engine performance by limiting torque and restoring the jet pump's function when fuel levels are critical.
Implementation Method 1
The jet pump is disposed on the return pipe and transfers the fuel stored in the fuel tank to the sub-tank by using a venturi effect by the surplus fuel to be returned to the sub-tank
Data Source
AI summary
An engine controller includes a fuel supplier and one or more processors. The one or more processors determine, based on an operation state of an engine, whether an operation point of the engine is in an engine operation range where an amount of surplus fuel to be returned to a jet pump is smaller than a predetermined amount. Upon entry into the engine operation range, the one or more processors obtain an amount of remaining fuel in a sub-tank, based on a travel state of a vehicle, and accumulate an amount of fuel injection after the entry into the engine operation range, to obtain an accumulated amount of fuel injection. When the amount of remaining fuel in the sub-tank is smaller than the accumulated amount of fuel injection, the one or more processors put limitation on maximum torque for each engine speed of the engine.