Vehicle Fuel Shutoff Valve Control for Stable Natural Gas Flow
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Solution Overview
Problem
Refuse vehicles equipped with natural gas fuel systems face inconsistent fuel flow due to mechanical regulators, leading to fluctuations in engine power and requiring cumbersome operator intervention to isolate individual fuel tanks.
Innovation Solution
A refuse vehicle design incorporating a fuel system with a shutoff valve and pressure sensor, controlled by a controller to manage fuel flow and pressure, along with an accumulator to buffer variations, and an impact mitigation system to protect the energy storage device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If mechanical regulators are used to reduce natural gas pressure, then fuel can be supplied to the engine, but the fuel flow becomes inconsistent and varies based on tank pressure
Solution Approach 1:
The patent replaces mechanical pressure regulators with an electronic control system that uses a controller, solenoid valve, and pressure sensor to actively manage fuel pressure. This substitution eliminates the inherent inconsistency of mechanical regulators by using electronic feedback control to maintain stable fuel flow regardless of tank pressure variations.
Solution Approach 2:
The system implements a feedback loop where a pressure sensor continuously monitors fuel pressure, sends signals to a controller, which then adjusts the solenoid valve to maintain consistent pressure. This closed-loop feedback mechanism ensures stable fuel flow to the engine even as tank pressure changes during operation.
2Object-affected harmful factors
If natural gas tanks are positioned along the chassis to isolate them, then safety is improved, but the vehicle wheel base becomes longer
Solution Approach 1:
The patent positions fuel tanks in the vertical dimension (above the chassis) rather than along the longitudinal dimension (along the chassis). This dimensional change allows tanks to be isolated for safety while avoiding the need for a longer wheel base, as the tanks occupy vertical space rather than extending the vehicle's length.
3Ease of operation
If operators manually engage valves at the head of each tank to isolate tanks, then fuel flow can be controlled, but operator effort and complexity increase
Solution Approach 1:
The system provides automatic tank isolation through electronic control. When a leak is detected by the pressure sensor or when isolation is needed, the controller automatically activates the appropriate solenoid valve to close the affected tank, eliminating the need for operators to manually access and operate valves at the head of each tank.
Solution Approach 2:
The patent introduces an electronic control system as an intermediary between the operator's need for tank isolation and the physical valve mechanism. The controller receives signals from pressure sensors and automatically actuates solenoid valves, serving as a mediator that simplifies operator interaction while maintaining precise control over fuel flow isolation.
Data Source
AI summary
A fuel system for a vehicle includes a fuel tank configured to provide fuel to an engine of the vehicle, a shutoff valve configured to selectively restrict a flow of the fuel along a flow path between the fuel tank and the engine, a temperature sensor configured to monitor a temperature of at least one of the engine of the vehicle or a temperature associated with a body area of the vehicle and provide a temperature signal, and a controller coupled to the temperature sensor and the shutoff valve. The controller is configured to control the shutoff valve to restrict the flow of the fuel in response to the temperature signal indicating a temperature in excess of a temperature threshold.