NAVISTAR UNVEILS CAMLESS DIESEL; 1ST TO POWER 2003 FORDS.
The engine's new hydraulically actuated G2.8SV injectors will be sourced from a new U.S. joint venture with Siemens AG. The digital actuators, atop the valves, were developed by Navistar in a joint venture with the Colorado-based Sturman Engine Systems.
Navistar . recently took the wraps off one of the auto industry's most anticipated products: an engine whose valve-train is operated electronically, without a camshaft.
In development since 1995, the so-called "camless" design will replace all of Navistar's light-duty on-highway diesels, including those powering Ford pickups, vans and SUVs. They'll enter production beginning in 2003 and ramp up in volume through 2007 -- the year the new federal Tier 2 emissions regulations begin for most light trucks.
The camless engines, including a modular V-6/V-8 family for Ford and an inline six for International trucks, are Navistar's technical solution for meeting the ultra-strict emissions laws, which critics say will be a challenge for diesels.
Rather than open and close its valves with conventional camshaft, pushrods or cam chain, lifters, rocker arms and valve springs, the camless engine employs an electro-hydraulic actuator mounted above the valves. It eliminates 140 parts, compared with a conventional diesel. On larger diesels it also eliminates the separate compression brake -- a £1,000 saving per engine.
The digitally-controlled system is an out-growth of Navistar's electro-hydraulic, low-pressure common rail fuel injection, It provides continuous, independent variable valve timing, lift and speed, which helps boost power, improve combustion and reduce engine-out emissions.
Controlling an engine's valvetrain electronically "opens the door for other future systems aimed at boosting efficiency and power," explains Dan Ustian, president of Navistar's engine group, "including cylinder deactivation and variable compression ratios."
The camless engines will feature advanced after treatment systems being developed by Degussa, Englehard and Johnson Matthey. They are designed to be operated on ultra-low-sulfur (less than 5 parts per million) diesel fuel. Navistar claims that NOx emissions will be reduced by up to 70%, with significant gains in fuel economy. Particulate emissions are claimed to be reduced to 90% below the EPA's proposed 2010 diesel regulations.
The first of the camless engines in production will be a new 4.5L V-6. It is slated for the 2003 Ford F-Series trucks, E-Series vans, Expedition and Excursion. To be built in a new, $250-million plant in Huntsville, Ala., the V-6 "will have performance equal to a diesel V-8, with 20% better fuel economy, a 35% manufacturing cost advantage and 70% lower NOx emissions," promises Charbonneau. "It will enable us to enter the under 8,500-pound light-truck market, including SUVs, in high volume." A 3.5L version will appear in 2005.