Variable Flow Rate High-Pressure Pump for Fuel Injection
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Solution Overview
Problem
Existing fuel injection systems for internal combustion engines face issues with pressure oscillations in the common rail due to synchronization errors and asymmetric delivery from pumping elements, leading to inefficient fuel flow and potential wear, especially under reduced power conditions.
Innovation Solution
A fuel injection system with a variable flow rate high-pressure pump, where the control unit introduces a multiplication factor (K) to adjust the timing of the metering solenoid valve's activation frequency, ensuring more precise synchronization and reducing slippage, thereby stabilizing the filling coefficient and minimizing pressure oscillations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a bypass valve is used to discharge excess fuel when the engine runs at maximum speed but with reduced power, then the flow rate is reduced, but compression work is dissipated as heat
Solution Approach 1:
The patent converts the harmful effect of excess fuel discharge into a beneficial one by using a variable flow rate pump. The pump's flow rate is automatically adjusted to match engine demand, so that fuel is not discharged but rather the pump simply delivers the exact amount needed, eliminating energy waste while maintaining precise fuel control.
Solution Approach 2:
The patent applies dynamics by using a variable flow rate pump whose flow rate can be continuously adjusted according to engine operating conditions. This dynamic adjustment allows the pump to adapt to changing fuel demands, eliminating the need for bypass valves and the associated energy losses.
2Productivity
If a throttle solenoid valve is used to restrict fuel flow, then the flow rate is reduced, but the fuel pressure becomes very low and makes little contribution to opening the intake valves
Solution Approach 1:
The patent uses a variable flow rate pump that dynamically adjusts its output based on engine demand. This eliminates the need for throttle solenoid valves that create pressure drops, allowing fuel to be delivered at appropriate pressure levels while still controlling flow rate through the pump's variable geometry.
Solution Approach 2:
The patent changes the fundamental parameter of fuel delivery from pressure-regulated flow (using throttle valves) to volume-regulated flow (using variable flow rate pump). This parameter change allows the pump to control flow rate while maintaining sufficient pressure to open intake valves effectively.
3Reliability
If return springs are set with very precise manner to guarantee valve opening, then the valve opening is ensured, but the pump becomes relatively expensive
Solution Approach 1:
The patent eliminates the need for precisely set return springs by using a variable flow rate pump that automatically provides the necessary fuel pressure. The pump's dynamic flow control ensures reliable valve opening without requiring complex spring calibration, simplifying the overall system.
4Ease of operation
If the metering solenoid valve is controlled synchronously with the pump shaft's frequency, then the timing is coordinated, but pressure oscillations occur in the common rail
Solution Approach 1:
The patent uses a variable flow rate pump that dynamically adapts its flow rate to engine demands, eliminating the need for synchronous control of metering solenoid valves. This dynamic approach prevents the pressure oscillations that occur with synchronous control while maintaining effective fuel delivery timing.
Data Source
AI summary
An injection system includes a high-pressure pump with at least one pumping element operated in a reciprocating manner by corresponding intake and discharge strokes. Each pumping element is equipped with a corresponding intake valve in communication with an intake line, fed by a low-pressure pump. An on-off solenoid valve is positioned on the intake line of the pump and is controlled by a control unit with a frequency equal to a whole multiple or submultiple of that of the pumping action, multiplied by a factor different from 1 and/or between 0.90 and 1.10, inclusive.