Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_17941111_2 (volume VARCHAR, co_2 VARCHAR)

### Question ###
Name the volume for co 2 for 168 g/km

### Accurate SQL ###

SELECT volume FROM table_17941111_2 WHERE co_2 = "168 g/km"