Behind the wheel of a CNG-powered big rig

At a recent Daimler Trucks North America (DTNA) event in Napa Valley, CA, I had the opportunity to drive a Freightliner Cascadia 113 tractor powered by compressed natural gas (CNG) engine that was hooked to a loaded van trailer.

Freightliner Trucks is a division of DTNA, the leading heavy duty truck manufacturer of Class 4 through 8 trucks.

This particular Cascadia 113 had a 12L Cummins Westport CNG engine rated at 420 hp and 1,450 lb-ft of torque with an Allison automatic transmission.

Clean and domestic

With near-zero emissions, natural gas trucks are among the cleanest trucks on the road and they reduce greenhouse gas (GHG) emissions of up to 20 percent versus comparable diesel engines.

Moreover, natural gas has physical properties that make it safer than gasoline or diesel because its range of flammability is extremely limited.

The rise in the domestic supply of natural gas since the advent of hydraulic fracturing technology has driven down the price of this fuel. While the average diesel price is around $4 per gallon, the same amount of CNG (one gallon of diesel fuel on an equivalent energy basis) can be bought for almost half the price.

A learning curve

This is all well and good, but what happens when you put the pedal to the metal. How does a CNG-powered big rig perform in the real world? Surprisingly well, I discovered during my time behind the wheel.

Trailer trucking around the Napa Valley, I found that the CNG-powered Freightliner Cascadia 113 tractor not only delivered the performance of a similarly diesel-powered truck, but was quieter. On average, natural gas engines run 10 decibels quieter than a comparable diesel engine, I learned.

However, there was a bit of learning curve for me. The tractor didn't jump like a diesel-powered tractor when I pushed down on the accelerator. There was a slight delay.

In my next blog, I'll talk about fueling a CNG truck.