What is a Flow Bench?
A Flow Bench is a basic system to measure and display volumetric air flow.
It is used as a tool for measuring and quantifying modifications and improvements made to items like automotive cylinder heads and carburettors by measuring the amount of air that they can flow. By measuring the volume of air that can be passed through the item the user can determine if modifications help improve air flow characteristics.
Traditionally constructed of a manometer and calibrated flow orifices, volumetric flow was calculated using mathematical methods. Modern flow benches use sensors to detect flow and reference pressures, flow calculations are now undertaken by microprocessor.
What is the DIY Flow Bench Project?
The DIY Flow Bench project (DIYFB) is a professional quality flow bench controller that produces results comparable with, and in some cases exceeding commercial grade systems.
The project comprises of two basic aspects.
Software
The software code is developed in C++ and runs on an ESP32 microprocessor. The ESP processes sensor data and uses the results to calculate volumetric flow data, which is then displayed via web browser on any web enabled device. The system can be used as a floating or fixed reference depression bench. When used as a floating reference bench the depression is automatically converted to a fixed value on-the-fly, allowing flow readings to be viewed at any chosen depression value.
The software also includes provision for data recording, allowing tests to be saved for later viewing and analysis.
The code is open source and is available under the GNU GPL V3 license.
Hardware
The hardware aspect of the project comprises of a PCB (commonly known as a 'shield') which connects to the ESP processor. The PCB includes environmental sensors to measure temperature, humidity and barometric pressure along with pressure sensors to measure the reference depression from the vacuum source. The shield also interfaces to a MAF sensor which allows the software to accurately measure and calculate volumetric flow. The circuit schematics are also open source which allows people to develop their own shields should they wish.
Both the software and hardware aspects of the project are available for free from the projects GitHub repository. The GitHub repo also contains all of the information needed to build your own volumetric flow bench in the form of a WIKI and Support forum.
The system supports the following systems architectures.
- MAF based benches
- Orifice based benches (In Development for V3 release)
- Pitot style benches (In Development for V3 release)
- Venturi style benches (In Development for V3 release)
The DIYFB system can therotically be used on any flow bench and makes an ideal retrofit for older manometer based benches as well as being the perfect choice for new builds. We include DIY hardware plans so you can build a basic MAF based flow bench that uses a shop vac for the vacuum source. This is a great entry level bench and perfect for most shops and hobbyists. We also provide support for larger and more complex bench designs.
Project Goals
- Validated software and hardware design.
- Affordable & easy to source components.
- Can be built & operated by a layman.
- Generates results comparable with commercial flow bench.
- Open source software and hardware design.
- DIY Shield kits available to purchase.
Specifications
Hardware
- Reference pressure (depression) sensor.
- Differential pressure sensor (for orifice / venturi / pitot based benches)
- Pitot sensor (Differential pressure sensor for pitot probe)
- MAF sensor (voltage and frequency* based sensors are supported)
- Temperature
- Barometric pressure
- Humidity
- Swirl Probe support*
- Serial Gauge protocol* (for recording valve lift data)
- DAC VFD control for vacuum motors
- DAC Bleed valve control
- Multi stage vac motor control
- Stepper motor control for bypass valve*
- Stepper motor control for automatic valve lift control*
- High speed input for turbine speed monitoring*
- Automatic orifice detection (for orifice / venturi / pitot based benches)*
- SD Card support for Data storage.
- Wifi
- Serial API interface
Software
- Wifi connectivity management
- Browser based GUI
- Serial based API
- Realtime display for flow / depression / temperature / barometric pressure / humidity / differential pressure / pitot / swirl
- User configurable system settings via GUI
- GUI based calibration
- Auto leak test function
- GUI based data handling
- Automated vacuum motor control
- Lift vs Flow graphs*
- Support for digital gauges*
- Support for automatic valve operation*
*support scheduled for V3 release
Download
You can download the latest release from our Githib repository
Support
Documentation is provided for installation, configuration and use in the WIKI
If you get stuck, feel free to create a discussion in the support forum, or hit us up over on the Discord channel.
If you find an issue, or have a feature request, please raise an issue
Licenses
Software
The software aspect of this project is released under the GPLV3 license. For details on usage please refer to the license file included with this project and available at https://github.com/DeeEmm/DIY-Flow-Bench/blob/master/LICENSE
Hardware
The hardware aspect of this project is released under the CERN–OHL–W license. For details on usage please refer to the license file available at https://github.com/DeeEmm/DIY-Flow-Bench/tree/master/PCB/LICENSE