Use Solr
This is a good question, actually, and one that I would recommend using Solr to solve.
In the Solr search engine you can define exclusion words - called stop
words - words that are common in language (the, there, for, but, these).
The best part is that these words are included in a file called stopwords.txt
. Modifying this file and restarting the Solr engine allows you to edit any word in the list of exclusions.
Add the word "car" to stopwords.txt
If that doesn't solve it, make sure the following line is in your solr.conf:
<filter class="solr.StopFilterFactory" ignoreCase="true" words="stopwords.txt" enablePositionIncrements="true" />
I don't want Solr
If you're dead-set against Solr, or want to try something else first - the easiest method to handle this without writing any code at all is to remove the word "Car" from your product's name entirely. There are a couple ways of doing this, but the easiest would be from within your theme's product view template to append the word "Car" to products with a certain attribute set. (This is kind of a hack, yes. This is why I recommend Solr.) This prevents the word 'car' from being indexed as your product's name. Searches containing the word car should be a bit more relevant.
The opposite approach will also work - remove the color name from the product name itself, use it as a product attribute instead and concatenate it as a part of the product name.