Which template engine Phalcon use?

Phalcon uses a powerful and fast templating engine called Volt.
Volt is an ultra-fast and designer-friendly templating language written in C for PHP. It provides you a set of helpers to write views in an easy way. Volt is highly integrated with other components of Phalcon, just as you can use it as a stand-alone component in your applications.

Also, Read Best Laravel 5 interview questions