Fuel Pump Control for Low Idle Volume Delivery
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Solution Overview
Problem
Fuel pumps in motor vehicles struggle to deliver minimal fuel volumes required during low idle conditions, leading to inefficiencies and increased costs due to either excessive or insufficient fuel compression, as commercially available pumps often operate below their minimum compressible limits.
Innovation Solution
A method that adjusts the fuel pump's operation by determining if the demanded fuel quantity is below the minimum deliverable volume, calculating the necessary number of compressions to reach the pump's minimum capacity, and adjusting the demand accordingly, allowing for precise fuel delivery by inhibiting the pump until the minimum volume is achieved, thereby optimizing fuel usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fuel pump operates at low idle conditions with minimal fuel demand, then the vehicle can maintain steady operation, but the pump delivers more fuel than needed because it cannot compress volumes below its minimum capacity
Solution Approach 1:
The fuel delivery is segmented into multiple compression cycles. Instead of attempting to deliver the minimal fuel demand in a single pump cycle (which falls below the pump's minimum compressible volume), the control method divides the delivery into several sequential compression cycles, each delivering a portion of the total required fuel. This allows the pump to operate above its minimum volume threshold while still meeting the overall low fuel demand.
Solution Approach 2:
The system dynamically adjusts the number of compression cycles based on the demanded fuel quantity. The control method calculates the required number of cycles as the ratio of minimum compressible volume to demanded volume, and dynamically modifies pump operation accordingly. This dynamic adaptation allows the pump to maintain efficient operation across varying fuel demand conditions.
2Loss of energy
If the fuel pump is inhibited for multiple compression cycles to deliver minimal fuel volumes, then fuel efficiency improves, but the control complexity increases due to iterative calculations and counter management
Solution Approach 1:
The control method employs feedback mechanisms through counters that track the number of compression cycles executed. The counter is initialized based on the calculated number of cycles needed, and decremented with each compression cycle. When the counter reaches zero, the pump inhibition is lifted. This feedback-based control structure manages the complexity by providing a systematic way to track and control the multi-cycle operation.
Solution Approach 2:
The control algorithm performs preliminary calculations before pump operation begins. The number of compression cycles is pre-calculated as the ratio of minimum compressible volume to demanded volume, and the counter is pre-initialized with this value. This preliminary action simplifies the ongoing control by establishing the inhibition duration in advance, reducing the need for complex real-time adjustments during pump operation.
Data Source
AI summary
Disclosed is a method for controlling a fuel pump for a motor vehicle, including determining if a set amount of fuel to be compressed is less than the minimum volume that can be delivered by the pump and, if this is the case, determining a new set amount of fuel to be compressed equal to the product of a number of compressions of a volume equal to the set amount of fuel to be compressed required to achieve at least the minimum volume that can be delivered and the set amount of fuel to be compressed; transmitting the new set amount of fuel to be compressed to the fuel pump; and subsequently disabling the fuel pump for a number of occurrences of the set amount of fuel equal to the number of compressions of a volume equal to the set amount of fuel to be compressed.