Electric GDI Fuel Feed With Variable-Speed Pressure Control
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Solution Overview
Problem
Shaft-driven high-pressure fuel pumps are inefficient and noisy, particularly at low engine speeds, due to engine load and solenoid-operated control valves, which also cause audible noise and fuel pulsations.
Innovation Solution
An electric motor-driven high-pressure fuel pump with passive inlet and outlet check valves, decoupled from engine speed, uses a variable speed DC motor to regulate fuel pressure, incorporating a low-pressure pump and eccentric drive mechanism to control fuel flow without solenoid valves, and cools and lubricates components with circulating fuel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If shaft-driven high-pressure fuel pumps are used to deliver fuel at high pressure, then fuel pressure can exceed 300 bar, but the pump represents a significant load on the engine and generates audible noise particularly at low engine speeds
Solution Approach 1:
The patent replaces the traditional shaft-driven mechanical pump system with an electric motor-driven pump system. The electric motor is coupled to the pump through a decoupling mechanism that allows the motor to operate independently from the engine shaft, eliminating the direct mechanical connection and reducing engine load and noise while maintaining high fuel pressure capability
Solution Approach 2:
The patent segments the fuel delivery system into independent components: an electric motor module, a pump module, and a decoupling mechanism. This segmentation allows the pump to be driven independently by the electric motor rather than being mechanically coupled to the engine shaft, reducing the harmful effects of engine-driven pumps
2Productivity
If solenoid operated inlet control valves are used to control fuel flow into the pumping chamber, then pump output can be adjusted to meet fuel demand, but the control valves represent a source of audible noise and cause fuel pulsations
Solution Approach 1:
The patent replaces solenoid-operated inlet control valves with an electrically controlled system. The electric motor's rotational speed is controlled by an electronic control unit that regulates power delivery to the motor, thereby controlling fuel delivery quantity without mechanical valves, eliminating valve-related noise and pulsations
Solution Approach 2:
The patent uses dynamic control of the electric motor's rotational speed to regulate fuel delivery. Instead of using static mechanical valves to control fuel flow, the system dynamically adjusts motor speed based on fuel demand signals from the engine control unit, providing smooth continuous control without pulsations
3Stress or pressure
If the pump is driven from the engine shaft, then the pump can deliver high-pressure fuel, but the pump operates continuously even when fuel demand is low, reducing overall system efficiency
Solution Approach 1:
The patent implements dynamic operation where the electric motor's rotational speed and power output are continuously adjusted based on actual fuel demand. The control unit receives signals from the engine management system and modulates motor operation accordingly, allowing the pump to operate at optimal efficiency across varying load conditions rather than running at constant high power
Solution Approach 2:
The patent replaces the engine shaft-driven mechanical connection with an electric motor system that can be independently controlled. This substitution enables the pump to be decoupled from engine operation and run only when needed, eliminating the mandatory continuous operation imposed by mechanical coupling to the engine shaft
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 electric GDI pump reduces engine load, eliminates audible noise, and provides precise control over fuel pressure, enhancing efficiency and reducing noise and fuel pulsations.
Implementation Method 1
fuel being pumped is drawn through the electric motor into the pump, where it is pressurized before passing through a high pressure outlet of the pump
Implementation Method 2
cool and lubricate a drive region of a high-pressure pump
Implementation Method 3
An eccentric drive is coupled to the drive shaft to converts rotation of the drive shaft into reciprocating motion of a pumping plunger
Data Source
AI summary
An electric GDI pump is configured to allow fuel being pumped to cool the electric motor and associated motor control/drive circuit, and cool and lubricate a drive region of a high-pressure pump before passing through an inlet check valve of the high-pressure pump. The rotational speed of an electric GDI pump is de-coupled from the rotational speed of the internal combustion engine. In such a fuel supply system, the quantity of fuel pressurized can be regulated by changing the rotational speed of the electric GDI pump. According to aspects of the disclosure an electric GDI pump is driven by a variable speed direct current motor having a motor housing with a fuel inlet and a motor drive shaft connected to a rotor. The electric GDI pump may incorporate a low-pressure pump driven by one end of the drive shaft and an eccentric drive driven by an opposite end of the drive shaft.