By now, the industry has scrutinized, analyzed and debated ad nauseum the merits and drawbacks of selective catalytic reduction (SCR) and advanced exhaust gas recirculation (EGR).

We also know that Cummins, Detroit Diesel, Mitsubishi Fuso, General Motors, Isuzu, Mack, Volvo, and others are going with SCR, while Navistar is going with EGR.

But what does it mean to the OEMs and body builders? What are the additional challenges in body- and equipment-mounting? What can be done with the diesel exhaust fluid (DEF) tank? What are the concerns about engine cooling and increased vehicle complexity?

Here's a look at seven leading chassis manufacturers and the issues related to mounting equipment on chassis that meet 2010 emissions requirements.

Dodge

Kevin Mets, lead engineer for heavy-duty pickup trucks and chassis cabs, said Cummins' 6.7-liter turbo diesel remains the same. He said Dodge is continuing the mantra it has been espousing for the last few years — that it wants to have the most upfit-friendly truck possible.

“When we designed this 2010 truck, our commercial vehicle team was part of all packaging meetings that went on,” he said.

He said the new parts include lines going to the DEF pump and to the DEF injector, and down to the SCR catalyst. The SCR module, “the brains behind the whole thing,” is mounted on the crossmember underneath the cab.

“With the cab on, most of the components are covered by the cab,” he said. “The tank is mounted under the cab. The filler pack is frame-mounted and is in a 3-inch zone between the back of the cab and the closest possible location we allow the upfit to be mounted. It takes advantage of the curvature of the back of cab.

“The pump is mounted on the frame rail and is inboard of all suspension components, so it's narrow enough that it has no effect on service-body applications or toolboxes off of flatbeds. The [power take-off] packaging area stays the same. All of that is carried over from 2009, so the packaging of the PTO should not be impacted by this new emissions package.

“As wheelbases change, the only thing that grows is the exhaust pipe after SCR. As far as consistency goes, the emissions system is the same no matter what wheelbase the system is mounted on.”

Engineering support manager Walther Bloch said the Sprinter tank is mounted under the cab and outboard of the frame rail. The fill neck is mounted to the frame and forward of the 3-inch plane, with no kit to install. The pump is mounted to the frame inboard of the leaf-spring bracket and there is clearance for service-body upfits.

On the exhaust side: the exhaust pipe between the turbo and diesel particulate filter (DPF) is common to 2009; the PTO environment/mountings also are common; and the SCR location relative to back of cab stays constant.

Sprinter curb weight will increase by 155 pounds for the chassis cab and 144 pounds for cargo. Due to chassis certification, Sprinters under 10,000 pounds gross vehicle weight rating (GVWR) cannot exceed the unloaded vehicle weight (UVW) and inertia weight of 7400 pounds, and Sprinters over 10,000 pounds GVWR cannot exceed the inertia weight of 10,470 pounds.

During tests, the average consumption of DEF for Sprinters was 0.6 gallons per 1000 miles. DEF service intervals are every 10,000 miles or once a year.

New engine performance is 185 hp at 3,800 rpm, an increase of 30 hp; new torque is 325 pounds per foot at 1,400 to 2,400 rpm, an increase of 45 pounds per foot.