how to integrate sensio/generator-bundle in custom application - not symfony

Question

I wrote a custom PHP application that is using Doctrine.
So Doctrine and the symfony/console component, as it's dependency are already installed.
Now Since symfony/console is already installed - I thought why not go all the way and install the sensio/generator-bundle component which gives me these wonderful code generation possibilities and ran
composer require sensio/generator-bundle

My composer.json

 "require": {
    "doctrine/orm": "*",
    "symfony/finder": "^3.1",
    "sensio/generator-bundle": "^3.1"
}

After reading how to enable the sensio bundle on symfony.com
I found out that - as with all bundles - , they have to be enabled in the AppKernel.php which ships with the symfony standard edition.

But ! of course my custom application does not have a AppKernel.php I try o figure out how to integrate this extra bundle into my own code / workflow.

Does anybody have experiences with this ?
And what are the important parts of the bundle that need to be registered / instantiated to work with them ?
Or is this simply to much work or not possible ?

Any help appreciated -- please --Thanks