Dual-Rail Fuel Injection Pump for High-Pressure Port and Direct Injection
Solution Overview
Problem
High-pressure direct fuel injection systems face limitations in providing desired fuel quantities at higher engine speeds and loads due to shortened cylinder stroke times, leading to reduced engine power and increased particulate matter emissions, and require additional pumps for high-pressure port fuel injection, increasing complexity and cost.
Innovation Solution
A system utilizing a high-pressure fuel pump to deliver fuel at variable pressure to direct injectors and fixed pressure to port injectors, with mechanical spill and check valves, allowing a single pump to provide higher port fuel injection pressure without additional pumps, and disabling direct injection during cold-starts or high emissions conditions to use high-pressure port injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If high pressure direct injection systems are used to reduce particulate matter emissions, then emissions are reduced, but the system requires additional pumps for high pressure port fuel injection, increasing complexity and cost
Solution Approach 1:
The high pressure fuel pump is configured to serve dual functions: delivering fuel at variable high pressure to direct injectors and at fixed high pressure to port injectors. The pump includes a first fuel rail coupled to an outlet for direct injection and a second fuel rail coupled to an inlet for port injection, with mechanical spill and check valves enabling pressure control for both injection systems without requiring additional pumps
Solution Approach 2:
The patent combines the port fuel injection and direct fuel injection systems into a single integrated fuel delivery architecture. Both injection systems share a common high pressure fuel pump, with the pump's inlet connected to the port injection fuel rail and outlet connected to the direct injection fuel rail, merging previously separate systems into one unified structure
2Loss of substance
If very high pressure direct injection systems are used to reduce fuel dilution in oil, then fuel dilution is reduced, but the dynamic range of injectors is limited by rail pressure, resulting in large fueling errors at low loads
Solution Approach 1:
The fuel injection system is segmented into two independent pressure zones: a high pressure direct injection system (250-800 bar) for reducing fuel dilution and a fixed pressure port injection system for maintaining accurate fueling at low loads. The segmentation allows each subsystem to operate independently within its optimal pressure range, with the port injection system providing precise fuel metering when direct injection pulse widths would be too small
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
This configuration enables higher port fuel injection pressures, reduces fueling errors, and improves engine performance by maintaining efficient fuel delivery and reducing particulate matter emissions.
Implementation Method 1
the fuel delivery controlled via a mechanical spill valve of the pump
Implementation Method 2
various additional check valves
Data Source
AI summary
Methods and systems are provided for operating a high pressure injection pump to provide each of high fixed fuel pressure at a port injection fuel rail and high variable fuel pressure at a direct injection fuel rail. Port injection fuel rail pressure can be raised above a pressure provided with a lift pump via a fuel system configuration that includes various check valves, pressure relief valves, and a spill valve positioned between an inlet of the high pressure injection pump and the port injection fuel rail. High pressure port injection may be advantageously used to provide fuel at high pressure during conditions when fuel delivery via high pressure direct injection is limited.