Fuel Pump Pressure Control via Periodic Action
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Solution Overview
Problem
Conventional fuel pump control methodologies result in inefficiencies, increased audible noise, vibration, and harshness due to operation at less than full capacity, and can impair reliability and durability by not aligning pumping cycles with fuel injector operations, leading to undesirable variability in rail pressure during fuel injection events.
Innovation Solution
A method of controlling a fuel pump with multiple pumping elements, where the operation is adjusted based on real-time rail pressure values to maintain desired pressure ranges, optimize efficiency, reduce noise, and enhance reliability by varying fuel delivery percentages and phasing relative to fuel injector events, including binary, phased, and gentle pumping strategies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fuel pump operates at less than full capacity during every pumping cycle to maintain rail pressure, then the rail pressure can be maintained within desired range, but the pump efficiency decreases and audible noise increases
Solution Approach 1:
The fuel pump is controlled to operate in periodic cycles, alternating between active pumping events and inactive periods. This periodic operation allows the pump to deliver fuel in discrete quantities rather than continuous flow, enabling the pump to operate at full capacity during active periods while maintaining acceptable rail pressure averages over time, thereby improving overall pump efficiency
Solution Approach 2:
The system anticipates fuel injection events and performs preliminary fuel delivery to the common rail accumulator before the actual injection occurs. By pre-delivering fuel during off-peak periods or when engine demand is low, the pump can operate efficiently and the rail pressure is already prepared for upcoming injection events, avoiding the need for continuous partial-capacity operation
2Reliability
If the fuel pump operates at less than full capacity during every pumping cycle, then the rail pressure can be maintained within desired range, but audible noise and vibration increase
Solution Approach 1:
By implementing periodic pumping cycles with distinct active and inactive phases, the system reduces the frequency of pump operations. The pump operates at full capacity during scheduled periods and remains inactive otherwise, which reduces cumulative noise and vibration compared to frequent partial-capacity operations, while still maintaining adequate rail pressure through strategic timing of pumping events
3Productivity
If pumping cycles are not in preferred phasing relationship with fuel injector operations, then fuel delivery can occur during every pumping cycle, but reliability and durability are impaired and rail pressure variability increases
Solution Approach 1:
The control system uses feedback from rail pressure sensors and injector operation status to dynamically adjust the timing and frequency of pumping cycles. By monitoring actual rail pressure levels and injector demand patterns, the system optimizes the phasing relationship between pumping events and injection events, ensuring pumps operate when most effective while maintaining reliable and durable operation patterns
Solution Approach 2:
The system dynamically adjusts pumping cycle timing and duration based on real-time operating conditions, including rail pressure levels, engine load, and injector demand. This dynamic adaptation allows the pump to operate in preferred phasing relationships with injectors under varying conditions, improving reliability and reducing pressure variability while maintaining adequate fuel delivery productivity
Data Source
AI summary
A method and system is provided of controlling a pump having a pumping element configured to provide pressurized fuel to a common rail accumulator coupled to a plurality of fuel injectors configured to inject fuel into a corresponding plurality of cylinders of an engine, comprising: receiving rail pressure values indicating a current fuel pressure in the accumulator; and responding to the received at least one rail pressure value by controlling operation of the pumping element during each potential pumping event of the pumping element to generate actual pumping events during at least some of the potential pumping events to cause the rail pressure values to remain within a desired range and to at least one of increase an overall efficiency of the pump, decrease audible noise generated by the pump, increase reliability of the pump and reduce injection pressure variations at the plurality of fuel injectors.