Design Ideation

Through research of prior intake designs and analytical calculations using Helmholtz resonator theory we are able to define initial design parameters such as runner length, plenum volume and intake geometry to create both initial parameters , boundary conditions and initial design concepts to begin further and more detailed analysis using simulation software such as GT- Power and ANSYS to further iterate between different designs and concepts. In this section we will describe and show our analysis models, simulation models and parameters, and validation methods for the intake manifold design.

INITIAL DESIGN CONCEPTS

After conducting research and discussing with our advisor, based on the constraints from the engine, rules, and relative available parts, the team came up with some initial design concepts. This designs are just concepts of our potential intake geometries and do not meet all the regulations, due to the fact, that additional simulations need to be perform to determine parameters such as runner lengths, runner diameters, plenum volume, among others. As the results from the simulations are obtained, the designs will be modified to obtain shapes that maximizes the performance of the vehicle. Creating geometries that minimize the amount of pressure drop and ensure that both cylinders are receiving equal airflow as the engine is running, this will allows us to reduce engine performance lost within the intake.

Concept 1

Model following basic understanding of maximizing plenum volume and a rough sizing constraints by the vehicles chassis and engine.

Concept 2

Model following basic understanding of airflow, streamlined for minimum wall resistance, with no wasted plenum volume like the first concept.

Concept 3

This model is a combination of the first two concept designs. It combines the ideas of the first two with a focus on throttle response and high rpm power, indicative characteristics of an ideal plenum volume.

MATERIAL SELECTION DESIGN MATRIX

To have the least restrictions on design geometry, we need to choose an appropriate material that meets our needs. From our own understanding and from the input of our stakeholders we created a weighted decision matrix to easily identify the material best suited for our use case. Ease of manufacturing and limitations on the geometry from the process used with each material was our biggest concerns as that will dictate the overall design of the intake. Cost is not a concern at this time as we will be getting the materials and manufacturing donated by sponsors of the Formula SAE team. For the durability goal of our team, there are two main factors we looked at, specific strength, commonly referred to as strength to weight ratio and glass transition temperature above the operating temperature of the vehicle as to not deform during normal operation. This temperature limitation removed two common materials for our intake due to temperature concerns. Our ideal material for the intake design based on this decision matrix is Ultem 1010 due to it's ease to manufacture in Stereolithography printing and high temperature resistance and good surface quality. Our backup material would be ABS printed using fused deposition modeling with a vapor smoothing post processing to get a polished surface finish and its high glass transition temperature.

ASSESSMENT PLAN

DETAILS OF THE PLAN

In the slides below, there is a detailed explanation of the of the Simulations Plan.

Details of Assesment Plan

SIMULATION SOFTWARES/TOOLS

Two main softwares will be use to perform all the simulations required to help obtained parameters and test our designs.

GT-Power

An industry standard software for simulating engine performance with the possibility of including physical models to extend its main function even further. [5] GT-Power will provide our team with accurate parameters such as engine volumetric efficiency, ideal runner length, and plenum volume that will be later used to develop the geometry of the system to provide optimal performance of the engine.

Ansys Workbench

A finite-element simulation software that is used to model and analyzed advanced multi-physics scenarios. [1] For the purpose of our project, ANSYS will serve as a complementary tool to GT Power. The obtained geometry will be analyzed under various aspects, such as fluid dynamics, structural, and vibrational.

VALIDATION METHODS

After the design has passed all simulations and had been manufactured, it will be time to see how accurate our simulations are compared to real world testing of the engine’s performance. This will be an analysis of simulation data against measured performance on a chassis dynamometer. In addition, technical inspection and on-track testing will be perform to ensure regulations compliance and durability of the design.

Technical Inspection

Before being able to perform at any of the FSAE competition events, the vehicle needs to pass technical inspection, to confirm that the car is in compliance with all the requirements and restrictions of the FSAE rulebook. To ensure that the designed intake pass all regulations, the team will perform a self-inspection using the Technical Inspection Form provide by FSAE. Thus, when competition time arrives, the team will be certain that the intake and its mounting mechanism to the engine will pass the inspection.

This image show a chassis dynamometer. It is a dyno, where the vehicle is anchored to the floor and the drive wheels are place in the rollers. The device measures the force that the car applies to accelerate the drums. The main benefit is that the entire drivetrain can be tested simultaneously to real world application.

Dyno Testing

A "dyno" (short for dynamometer) is a device used to measure the force, torque, and power of an engine. It creates a load that duplicates various speed and torque requirements, which then allows the calculation of the amount of power in the engine. For our project a chassis dyno will be used to test and measure the engine performance and volumetric efficiency, both of the stock engine and of different intake designs iterations. This will allow us to confirm the performance parameters obtained through simulations. Since the early intake designs will be split to two parts, we can easily swap out different runner lengths, diameters, and plenum volumes during dyno time to see and compare performance changes in real time. The results from this tests, will allow us to compare the designs and will help us decide which is the configuration is the optimal one. [9]

On-Track Testing

Full on track testing intake durability through full track run and compare on track performance between intake design to view lap time differences and measure intake life cycles with one cycle equating to one full endurance run. For intake durability, after a testing run a physical inspection of the part will be done to analyze for any cracks , part delamination, or dents . Afterwards a non destructive testing method "Leak Testing" specifically Vacuum Decay test will be done to ensure the part can still maintain proper vacuum after testing. Lap times, driver feedback and on track data will be used to view the power output of the engine thought-out the track and help us validate that the intake is designed to the proper rev range needed for competition.

Image represents an eight cylinder intake manifold on a flow bench.

Flow Bench Testing

Flow testing is the term used to test the air flow capability of engine components on a machine called a Flow Bench. This device measures airflow across a known orifice size by measuring its pressure differential. By testing on a flow bench, we can determine the iteration design with the least amount of airflow restriction which can improve the power potential of internal combustion engine to make power. This important steady state test can be beneficial in getting real-world airflow data. Flow bench test are best used for comparing between intake manifolds, which is what we will be doing while deciding between our different iterations. Modifications can also be performed to engine components and flow tested on a flow bench to improve air flow in order to develop more power and better engine performance. Flow testing on a flow bench is an effective method used for testing the flow capability of engine components that affect engine airflow.

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