Variable Stroke DI Fuel Pump Actuator for Engine Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional direct injection (DI) fuel pump systems experience increased pumping losses and decreased fuel economy during certain engine operating conditions where a full stroke of the DI fuel pump is not required, leading to inefficiencies.
Innovation Solution
A variable stroke direct injection fuel pump system is introduced, which includes a DI fuel pump with a stroke member actuated by a variable fuel pump actuator assembly. This assembly is controlled by an engine control unit (ECU) based on operating parameters like accelerator pedal position, engine speed, and fuel pressure, using hydraulic fluid pressure to adjust the stroke of the DI fuel pump, thereby reducing unnecessary pumping losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a full stroke of the DI fuel pump is used during certain engine operating conditions, then the fuel pump can supply maximum fuel, but pumping losses increase and fuel economy decreases
Solution Approach 1:
The patent implements a variable stroke mechanism that dynamically adjusts the fuel pump stroke length based on engine operating conditions. The actuator member varies the stroke from a full stroke (maximum fuel supply) to a reduced stroke (lower fuel supply) according to real-time engine demands, allowing the system to optimize between fuel supply quantity and pumping losses by matching pump output to actual engine requirements
Solution Approach 2:
The patent changes the physical parameter of stroke length to resolve the contradiction. By varying the stroke parameter from fixed full stroke to variable stroke lengths, the system can reduce pumping losses during low fuel demand conditions while maintaining adequate fuel supply during high demand conditions, directly addressing the trade-off between quantity of fuel supplied and energy losses
2Loss of energy
If a variable stroke mechanism is added to the DI fuel pump, then pumping losses are reduced and fuel economy improves, but device complexity increases
Solution Approach 1:
The actuator member serves multiple functions: it acts as both the actuating mechanism for the fuel pump stroke and as a controllable valve element. This multi-functionality reduces the need for separate components, thereby limiting the increase in device complexity while still achieving variable stroke capability to reduce pumping losses
Solution Approach 2:
The patent introduces a control valve as an intermediary element that regulates hydraulic fluid flow to the actuator member. This intermediary allows precise control of the variable stroke mechanism through hydraulic pressure modulation, enabling complex control functionality while keeping the mechanical structure relatively simple through the use of fluid control rather than direct mechanical actuation
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
The system achieves reduced pumping losses and improved fuel economy by selectively adjusting the stroke of the DI fuel pump according to engine conditions, such as during low engine load or deceleration events, resulting in decreased noise, vibration, and harshness (NVH).
Implementation Method 1
a hydraulic fluid pump configured to pump the hydraulic fluid to the control valve and selectively to the actuator member in response to actuation by one or more lobes of a camshaft
Implementation Method 2
the control valve configured to control the hydraulic fluid pressure at the actuator member by controlling a flow of hydraulic fluid to the actuator member
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A variable stroke direct injection (DI) fuel pump system for an engine includes a DI fuel pump (136) having a stroke member (278) and configured to pump a quantity of fuel based on a stroke of the stroke member (278). The system includes a variable fuel pump actuator assembly (212) comprising an actuator member (270) configured to actuate the stroke member (278), a control valve (224) configured to control a flow of hydraulic fluid to the actuator member (270), and a hydraulic fluid pump (262) configured to pump the hydraulic fluid and be actuated by one or more lobes (216) of a camshaft (120). The system also includes an engine control unit (ECU) configured to control a variable stroke of the stroke member (278) by controlling the control valve (224) based on one or more operating parameters of the engine.