Japanese auto parts maker Denso Corp. said Thursday it will expand operations at one of its factories in Mexico, adding a new line to manufacture alternators for its North American customers from October 2014.

Denso will invest approximately $51.4 million (about ¥5.1 billion) to expand the Silao plant, which will start producing air conditioners in October, to accommodate the new line for customers such as Ford Motor Co. and Toyota Motor Corp., as they increase production in the region.

With the expansion, the car parts maker affiliated with Toyota will double the number of workers at the Mexican facility to 850 by 2015.

The Silao plant, about 290 km northwest of Mexico City in the state of Guanajuato, is the third for Denso in the Latin American country.