July 15, 2014 1:00 PM, EDT
Navistar Ships SCR-Equipped Vocational Models

Navistar Inc. has begun customer shipments of International vocational trucks with two versions of its in-house 9.3-liter engine that are equipped with selective catalytic reduction emissions technology, the company announced.

International DuraStar and WorkStar vehicles powered by MaxxForce 9 and MaxxForce 10 diesels — which share a 9.3-liter, 6-cylinder displacement but are spec’d with different power ratings — are delivering fuel-economy improvements of up to 8% over previous versions that relied on exhaust gas recirculation emissions technology, Navistar said in a statement, citing the results of internal testing.

“Our field-test customers are seeing positive results — with our new trucks registering significant fuel-economy improvements,” said Bill Kozek, the company’s president of North America Truck and Parts.

International DuraStar trucks can be spec’d with the MaxxForce 9 in ratings from 275 horsepower and 860 pound-feet of torque up to 330 hp/950 pound-feet torque. WorkStar models are available with the 275 hp/860 pound-foot engine or a MaxxForce 10 spec’d up to 350 hp and 1,150 pound-feet of torque.

The engines were tested in Alaska, Colorado and Arizona across vocational duty cycles that included garbage packing, utility trucks, dump trucks and sewer pumpers, the company said.