There are many different engine setups, each with their own set of advantages and drawbacks. We will explore these in a moment, but first we need to understand the system that the engine is part of, the powertrain.
Here is a visual representation of the powertrain from H-Point.
First of all, there is the engine. Conventional internal combustion engines (ICE) react fuel with oxygen to release energy that is transmitted to the wheels.
This process, naturally, starts with the transmission. Attached to the end of the engine, it can deliver power at various speeds. To do this, a clutch or torque converter is positioned between the engine and the transmission for manual or automatic transmission, respectively.
Final Drive is the series of shafts and gears that connects the transmission with the wheels, giving them power to turn.
No machine is 100% energy efficient. Unused energy is released in the form of heat, which is what makes engines hot during use. Cooling modules prevent the engine and other systems from overheating. They are placed where cool, moving air is easy to access.
The fuel tank's capacity depends on the size and intended range of the vehicle. The most important consideration is placing the fuel tank somewhere safe in case of a collision.
The combustion reaction that occurs in the engine produces H2O and CO2. These gases must be removed so that fresh air can enter the engine. The exhaust system expels these products.
Electric Powertrains come in two forms: Battery and Fuel Cell (FC). Batteries store electrical energy while fuel cells generate it using compressed hydrogen gas.
Both use a battery, but the FC system's is a smaller, supplementary energy source.
The FC system has hydrogen storage tanks that feed the fuel cell stack.
Both systems use an electronic converter to control the amount of energy given to the motors.
Electric motors are small and powerful, which allows for easy packaging on the axle or even the individual wheels.
There is also no need for a transmission like in the ICE. However, the fuel storage tanks and batteries are much larger than a conventional fuel tank. They are usually positioned under the floor, which saves space and creates new design possibilities.
There are two ways to position a conventional engine: longitudinal and transverse.
In longitudinal engines, the output shaft is parallel to the vehicle (front-back), while in transverse engines, the output shaft is perpendicular.
Transverse engines save space, but are constrained by the width of the frame rails.
Longitudinal engines take up more space but allow for larger engines to be installed between the frame rails.
Below are all of the possible engine configurations and some examples. Notice how the placement of the engine affects the architecture.
Front engines are positioned beyond the vehicle's front spindle (the shaft that turns the wheels).
 |
| Mini Cooper |
 |
| Dodge Viper |
Rear mid-engines are located between the rear spindle and the driver.
 |
| Bugatti Veyron |
Rear engines come after the vehicle's rear spindle.
 |
| Porsche 911 |
That's all for this week!
An excellent description of the engine and transmission. Is there an efficiency benefit to Transverse engine or are there other benefits? Is there a benefit to having the engine in the rear of the car or is it just buyers preference?
ReplyDeleteTransverse engines are easy to package and save a lot of space, which makes them ideal for passenger cars.
ReplyDeleteMid-rear longitudinal engines are ideal for high performance cars because they optimize weight distribution for handling. However, this usually eliminates the possibility of rear passengers, which is usually not a concern for these vehicles.
Rear longitudinal engines put a lot of weight on the rear wheels, providing great traction. This engine layout is not that common anymore, but the Porsche 911 has had a lot of success with it.
If a customer wants to have comfortable rear seating, then rear engines are basically not an option. Rear engine cars are usually more concerned with performance than comfort. Large front engines can be used in a high performance car, but they usually create a lot of front overhang.