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Engine Preview: Paccar MX

Paccar's MX is now being developed for US EPA 2010

March 2008, TruckingInfo.com - Feature

by Steve Strurgess, Executive Editor

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Underscoring the upcoming introduction of its own big-bore engine, Paccar recently hosted a press visit of its DAF facilities in Europe where the engine has been in production for more than two years. 

The tour included the engine labs that have been significantly extended and enhanced, adding capacity and technology to prepare Paccar engines for the next emissions steps in both North America and Europe. Additional Paccar facilities visited included the site for production of the engines for current DAF trucks and the test track for an opportunity to drive the 12.9-liter that will power Peterbilt and Kenworth trucks here by the end of the decade. 

The visit included an opportunity to see DAF trucks in production in the United Kingdom and in The Netherlands. 

At the big RAI Centre show in Amsterdam, DAF showcased its hybrid truck effort with an announcement of a pilot program for the UK.

Of course, the 6-cylinder big-bore MX was not new to the Dutch show. It was introduced at the Hanover truck show late in 2004, entering production in May 2005. In the interim it has been used with great success by Paccar's European brand DAF to power nearly 35,000 cabover XF and CF heavy trucks. In many European markets where these international and regional haulers compete, a combination of Paccar quality and process and the MX engine's performance and reliability have propelled DAF to the No. 1 or 2 market position.

In production at the plant in Eindhoven in the Netherlands, the 12.9-liter MX is destined to come to these shores by 2010. Already it has been shown at last year's Mid-America and Dallas truck shows. At the latter, the engine was featured in both Peterbilt 389 and Kenworth T800 models. This time in the Netherlands, during the tour of the vastly extended engine research and development facilities in Eindhoven, we saw both a Kenworth and a Peterbilt with MX engines installed.

By the time the engines become options in the Paccar brands in North America, the 12.9-liter engine will be assembled here in a plant currently under construction in Columbus, Miss. While Paccar officials are being very close-mouthed about its introduction, a release in the 2009/2010 timeframe is highly likely. Introduction in 2009 would allow the engines to be introduced with EGR emissions technology which, based on the Kenworth and Peterbilt examples viewed in both the United States and in Holland, may well include series turbocharging. For the 2010 regime, the high specific output of the MX may mean it will also feature selective catalytic reduction as an exhaust aftertreatment. For Euro 5, which is a popular spec in Europe, the MX features SCR.

The introduction of the MX in the Paccar brands here is a widely anticipated move by Paccar. The engine is an entirely modern design with sufficient displacement to offer up to 510 horsepower and 1,850 pounds-feet of torque in its current European configuration. By hiking production to include Peterbilt and Kenworth, Paccar can maximize the investment in the engine while moving both North American brands towards a more vertical model, less dependent on engine suppliers Cummins and Caterpillar. 

Also, having its own engine allows Paccar to be more sensitive to market demands and less captive to increased pricing from the engine suppliers or even to production interruption should one decide to withdraw from the marketplace come 2010.

Engine Specification

The 12.9-liter MX has wet cylinder liners to give more direct cylinder cooling and engine rebuildability. An in-block camshaft operates the valves and unit injection pumps, enabling a low engine height and fewer components - both desirable in its current cabover installation. Compact graphite iron for the block and cylinder head saves weight, yet adds stiffness and contributes to the engine's durability and low noise levels. 

The one-piece, cross-flow cylinder head features an integrated inlet manifold and four valves per cylinder fitted in a 30-degree diamond position. The overhead and powerful engine retarder were developed by Jacobs.

The engine's SMART high-pressure fuel injection system was developed in cooperation with Delphi and is fully integrated into the cylinder block. Injection follows a multiple-event strategy with pre-injection and post-injection cycles for emissions control with low noise. The MX also features a Wabco air compressor and an integrated oil module with cartridge filter, oil cooler, spinner bypass filter and thermostat.

To date, Paccar has not decided on the technologies it will use to meet 2010 standards, said Alan Treasure, Paccar director of marketing during the engine laboratory visit. 

"We're testing [SCR], but we're also testing every other technology," he said to my question about the two-stage, series turbocharging. "Even though they are using SCR in Europe, they are happy to work with us on an EGR solution," added Jeff Sass, Kenworth director of marketing, planning and research. "It's truly a global company."

Testing is ongoing at this new engine research and development center in Eindhoven. It has recently been expanded with 20 new emissions and durability cells to a total of 34 cells. This supports DAF engine production - there's a 9.2-liter as well as the 12.9 - currently running at a total 50,000 engines a year. The laboratory is so new that it had yet to be officially opened by fall 2007.

The new MX engine is a compact package weighing only 2,510 pounds as it is available in DAF's heavy-duty CF and XF models. In those trucks, it is mostly paired with the 12-speed ZF AS Tronic automated transmission, available in North America through ArvinMeritor as the Freedomline. This is the setup we were able to drive (see sidebar) at the DAF proving ground near Eindhoven in Holland. In North America, given the much slower acceptance of the automated transmission, the Peterbilt and Kenworth installations will likely feature a wide availability of different transmissions, perhaps even the manual 16-speed ZF alternative to the AS Tronic.

DAF Trucks

DAF is a long-established Dutch manufacturer of commercial vehicles that traces its heritage back over 100 years. It was also a car manufacturer for a while in the '60s and '70s with a diminutive sedan that featured the world's first continuously variable transmission (CVT). 

In the fascinating DAF museum in the city of Eindhoven, there are many examples of this little car - called in some markets the Daffodil - alongside DAF medium and heavy commercial vehicles. Like the little car, many of these established new ground in design with their introductions over the years - in fact, winning the International Truck of the Year award from the European truck editor judging panel more than a few times.

DAF has three classes of trucks: the medium-duty LF in a range of models, the regional and vocational heavy CF and the high-rise long-haul XF - all cabovers.

The LF is particularly interesting for North Americans, because it is the basis for the Kenworth K260 and 360 and the Peterbilt 210 and 220 low cab-forward Class 6 and 7 mediums. It is built in the United Kingdom and brought to America as a premium, Paccar-powered (with its proprietary Cummins ISB) low COE. 

Main production of the heavy-duty CF and the XF is in Eindhoven in Holland. The more modern is the CF, which is a strong contender as a tractor and straight truck in 6x2, 6x4 and 8x4 configurations in the vocational and regional-haul markets. These tend to be distinct and national in Europe, though still crossing the old borders in the now confederate states of the European Community. The XF is the first of the truly modern DAF heavies and was conceived to maximize the driver space within the short available envelope of European cabovers. It is built out to the maximum width and length practicable, and in its Super Spacecab configuration, to the maximum height as well. In its latest XF105 iteration, it was International Truck of the Year 2006 and featured the newly introduced Paccar MX engine at three ratings - 410, 460 and 510 horsepower. 

Driving the MX

Lined up for us to drive at the Dutch proving ground were a selection of XF and CF models and a single LF. I had recently driven the smallest DAF, both as a Kenworth and a Peterbilt Class 7, and found it just a jewel of a truck: easy to drive with a synchronized six-speed, precise, light steering, great visibility, excellent ride and so, so quiet.

Many of those virtues were found on the CF and XF - but on a bigger scale.

The CF was extremely nice to drive, with plenty of room for the driver, even if tight in the narrow sleeper. It was an extremely modern feeling, with a nice automotive style dash and loads of burlwood accents. The ride was smooth and the driving an exercise in quiet comfort. CFs had both the astoundingly good 12-speed AS Tronic automated transmission and also the air-assisted manual ZF 16-speed. 

The MX engine worked particularly well with the AS Tronic and, despite being loaded to 40 tonne (88,000 pounds) the CFs got up to speed nicely with no fuss.

It was the big XF, though, that I really wanted to experience. It has the huge boxy cab that is mounted on four suspension points that are very softly sprung. There are four steps up and the cab floor is nearly five feet from the ground. It rocks as you climb aboard. As you nudge the transmission into gear and take off, the cab settles back on its suspension. As throttle eased and the transmission shifted, the cab would rock forward and then back again as the clutch engaged and the electronics poured on the coals.

While this takes a little getting used to, the ride that the truck suspension and cab provide are very easy to get to like. With a test driver beside me, I was instructed to get off the billiard-table smooth lanes of the track and attack some of the deliberately rough sections of the durability course. The XF truly amazed with its ability not only to absorb outrageous potholes and surface changes, but to do so without my losing any measure of control. Wheels stayed on the ground, the steering retained feel without any kick back. It was just a magic-carpet ride despite the awful road conditions.

We were supposed to be experiencing the MX engine, but the only sensation to come through was of comparatively effortless propulsion. The biggest horsepower MX has a torque curve flat at 1,850 pounds-feet from 1,000 to 1,400 rpm. Then as the torque starts to fall, the horsepower has risen to 510 horsepower and stays flat right out to rated speed at 1,900 rpm. The effortless gaining of speed is the only sensation. You absolutely cannot hear what is going on, so quiet is the engine and so good the cab insulation.

Peterbilt and Kenworth will offer the MX 12.9 liter alongside Caterpillar C13- and C15-liter as well as Cummins 12-, 15- and 16-liter ISX engines. It will provide customers with an additional choice of power, said Dave Giroux, Peterbilt's director of communications during the visit to Eindhoven. 

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