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 CARS_DATA (edispl INTEGER, Id VARCHAR)
TABLE: CREATE TABLE CAR_NAMES (MakeId VARCHAR, Model VARCHAR)

### Question ###
What is the average edispl of the cars of model volvo?

### Accurate SQL ###

SELECT AVG(T2.edispl) FROM CAR_NAMES AS T1 JOIN CARS_DATA AS T2 ON T1.MakeId = T2.Id WHERE T1.Model = 'volvo'