Rocket Fuel

Tech Talk 40 – Engine Part 3

Machining of Individual Components Complete, Engine Prototype Testing Next

In part one of this series on Elio engine development we discussed the need to develop a new engine from the ground up. As we dove deeper into the vehicle’s design, it was clear the Geo Metro engine upon which we hoped to base our design would not provide the right balance of power and fuel economy.

Our engine development partner, IAV, went back to the drawing board and was able to configure a new engine design, while sticking to one of Elio Motors basic tenets for the company – use existing technology, but package it in a way that still meets the company’s performance and fuel efficiency targets. Even though the company is using tried and true technology, we still needed to ensure that each individual component is engineered and machined to rigorous specifications. Each component must be tested and validated individually, then packaged together as one working prototype.

None of this can be done using mass production techniques, so it is one of the more meticulous portions of the vehicle development process. It is also one of the most important portions of the vehicle development process, as the engine is one of the keys to meeting our fuel efficiency and performance criteria. Ultimately, how this engine performs is going to be a crucial element driving our customer satisfaction. Therefore, due diligence and proper development are essential to a successful engine program launch.

 Block Machined

Figure 1: Elio Finished Machined Block

    Valve Cover

Figure 2: Elio Finished Machined CAM cover and Crankshaft


Here is the good news. Approximately 99 percent of the components have been machined and are ready to put together as an engine prototype. Given that this new engine will have dozens of individual parts, this is an important step to define how each component will fit together and how the clearances align to the Computer Aided Design (CAD) components.

Block Machined side

Figure 3: Finished Elio Block

Now that we have the majority of these parts machined, we are ready to put together our first prototype and test it using a dynamometer. The first step before going on a dynamometer will be to make sure the engine is ready to run.  This involves making sure the engine spins freely, holds water, does not leak and maintains proper oil pressures.  The next step in the process allows us to run the engine through a variety of simulations to test force, power torque and combustion behavior, and test how the Engine Control Unit performs.  These simulations will include both city and highway driving conditions to see how the engine performs at various loads.

Block AssemblyFigure 4: Elio Block Assembly

Once this analysis is complete, we can make whatever minor adjustments are needed to ensure each portion of the engine is helping maximize fuel efficiency and power.  At that point, we will be very close to having the technical knowledge and feedback to finalize the production intent engine architecture.

Next week, we will take a closer look at the final prototype and the process for testing on the dynamometer.

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