innovation and invention

there has long been a question yet to be truly answered;

how different is innovation from invention?

have a glance at the following stories:

1. i have invented a new engine which consumes 10 liters of oil and produces 2 horse power
2. i have invented a new engine which consumes 0.2 liter of oil and produces 100 horse power
   

both are inventions and i am an inventor but in which case am i an innovator?


yes innovation must creates value and eliminates existing waste or simply it must render positive change in the existing status of something