Engine design is at the confluence of three factors: concerns about how car emissions will affect the environment; rising gas prices and the need to conserve fossil fuel resources; and the realization that the hydrogen-powered car -- be it powered by a hydrogen fuel cell or by hydrogen internal combustion -- will not deliver on its promise in the near future. As a result, many engineers are giving more interest to improving the internal combustion engine.
Photo courtesy Quasiturbine.com
Quasiturbine engine. See more images of engines.
The Quasiturbine engine, patented in 1996, is just such an improvement. In this article, we'll introduce the Quasiturbine engine and answer the following questions:
- Where did the idea for the engine come from?
- What are the parts of the Quasiturbine engine?
- How does the Quasiturbine engine work?
- How does it compare in performance to other internal combustion engines?
Let's get started by looking at some engine basics.
To see how a Quasiturbine engine works, you need to understand some engine basics.
The basic principle behind any internal combustion engine is simple: If you put a tiny amount of air and high-energy fuel (like gasoline) in a small, enclosed space and ignite it, the gas expands rapidly, releasing an incredible amount of energy.
The ultimate goal of an engine is to convert the energy of this expanding gas into a rotary (spinning) motion. In the case of car engines, the specific goal is to rotate a driveshaft rapidly. The driveshaft is connected to various components that pass the rotating motion onto the car's wheels.
To harness the energy of expanding gas in this way, an engine must cycle through a set of events that causes many tiny gas explosions. In this combustion cycle, the engine must:
- Let a mixture of fuel and air into a chamber
- Compress the fuel and air
- Ignite the fuel to create an explosion
- Release the exhaust (think of it as the by-product of the explosion)
Then the cycle starts all over again.
How Engines Work explains in detail how this works in conventional piston engine. Essentially, the combustion cycle pushes a piston up and down, which rotates the drive shaft by way of a crankshaft.
While the piston engine is the most common type found in cars, the Quasiturbine engine operates more like a rotary engine. Instead of using piston like a typical car engine, a rotary engine uses a triangular rotor to achieve the combustion cycle. The pressure of combustion is contained in a chamber formed by part of the housing on one side and the face of the triangular rotor on the other side.
The path of the rotor keeps each of the three rotor peaks in contact with the housing, creating three separate volumes of gas. As the rotor moves around the chamber, each of the three volumes of gas alternately expands and contracts. It is this expansion and contraction that draws air and fuel into the engine, compresses it, makes useful power as the gases expand and then expels the exhaust. (See How Rotary Engines Work for more information).
In the next few sections, we'll see how the Quasiturbine takes the idea of a rotary engine even further.