**1.3 Different types of powertrains**

In the previous section, two main types of the modern powertrain are discussed i.e. hybrid power train and full battery-electric powertrains.

In this section, a comparison of different types of powertrains is presented (refer **Figures 5**–**7**).

Multiple parameters influence the selection of the powertrains types to implement in the vehicle such as vehicle operating range, power requirements, charging time, cost, availability of access to charging infrastructure, etc.

Battery electric vehicles powertrains (refer **Figure 5**) are comparatively simples in the structure. These vehicles operate very efficiently. However, they need significant time for the recharging so the vehicle will be down until it recharges. It is expensive to increase vehicle travel distance range mainly due to battery prices.

A hybrid power train (refer **Figure 6**) utilizes the current powertrain configuration and adds the battery/emotors to enhance the performance of the powertrain as well as extend the operating range by improving the fuel efficiency of the internal combustions' engine. It does not require an exclusive charging infrastructure as it primarily runs on fossil fuels. However, this powertrain does have emissionrelated concerns and having more number of rotating parts makes the powertrain complex due to effective management of dual power sources is essential optimum performance.

Practically, environmental impact due to fuel should be considered from well to tailpipe or from the source of raw material to conversion into power for vehicle propulsion. Considering this criterion battery vehicles are not completely emissionfree vehicles. In a true sense, fuel cell vehicles (refer **Figure 7**) are practically green vehicles as they are not emitting any emission to the environment. Fuel cell powertrain uses hydrogen as prime energy source and utilizes chemical reactions process to charge the battery. Post electric energy conversion hydrogen atoms react with oxygen and forms water (H2O) which gets emitted from the tailpipe. Battery electric vehicles and fuel cell vehicles are having similar configurations except in addition to battery storage the fuel cell vehicles also require hydrogen fuel storage.

**Figure 5.** *Battery electric vehicle powertrain.*

**Figure 6.** *Hybrid electric powertrains (HEV).*


**Figure 7.** *Fuel cell vehicle powertrain.*

All the modern powertrains are available commercially, however, its penetration is driven by multiple commercial factors including acquisition cost, operation cost, and ease of re-charging (refueling). All these modern powertrain configurations uses multiple types of bearings in the powertrain including deep groove ball bearings, needle roller bearings, special ceramic rolling element bearings with many other features to provide intended functions in the vehicles which are discussed in the following sections.
