fuel economy


2017 Hyundai Elantra Limited – Rising Star In a Shrinking Market

2017 Hyundai Elantra Limited

2017 Hyundai Elantra Limited

As an engineer at heart, I can’t help but be excited by the technology that is likely to transform the transportation ecosystem over the next couple of decades. But as someone that actually likes to drive, the move toward autonomy is kind of depressing but realistically, that’s unlikely to affect me much for many years to come. On the other hand, the market shift away from cars toward utility vehicles is much more concerning right now. Some automakers are already scaling back their car development efforts in favor of utilities a number of the car nameplates on sale today will not be replaced at the end of their lifecycle. Fortunately, most automakers haven’t given up on cars just yet, among those is Hyundai which has just launched an all-new version of the Elantra compact.

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Saving Fuel and CO2 vs NOx Emissions With a Volkswagen Diesel

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We bought our 2010 Volkswagen Jetta TDI wagon in November 2009 in large part based on the potential money we’d save at the pump. In the wake of the current diesel emissions fiasco and the fact that until recently, diesel has consistently been more expensive than gasoline, last night Julie? asked if we’ve even managed to save any money with this car.

I went to the Energy Information Administration website (an outstanding resource for historical data on fuel prices and supply) and downloaded the monthly average price data for the midwest which is available in a handy excel spreadsheet. You can also get national and regional data for annual and weekly averages. Based on the total mileage accumulated over 70 months and the EPA combined fuel economy estimates of 34 mpg for the diesel and 25 mpg for the 2.5-liter five-cylinder that was also available at the time I worked out the average monthly fuel consumption over the time we’ve owned the car. We have used approximately 23.1 gallons of ultra-low sulfur diesel per month and would have used about 31.4 gallons of regular gas with the five cylinder.

Putting that up against the average monthly price of regular gas and diesel we would have spent approximately $7,274 on gasoline. By comparison, despite the higher pump prices most of the time, I estimate that we’ve spent roughly $5,732 on diesel fuel, a savings about $1,540 dollars. The diesel emitted approximately 16.3 tonnes of CO2 over the past six years while the gasoline-fueled version would have output almost 19.4 tonnes, so we’ve saved roughly three tonnes of CO2 as well.

Does that justify all the extra NOx we’ve emitted? I have no idea. That’s one of those trade-offs that you simply can’t measure directly. Having paid a roughly $2,000 premium up front to buy the diesel engine, the economics are still an open question right now. A week ago, the $3,500 in extra resale value of a diesel compared to a gas engine would have more than covered the $500 difference we’re at right now in fuel savings and we would have been way ahead financially. A few weeks from now when this all sinks in, who knows what this car will be worth.

I don’t have answers yet, just some random data points. Stay tuned.


Updated Chrysler Pentastar V6 Hints At Next-Gen Emissions Rules

3.6-liter Pentastar V-6 adds cooled EGR for model-year 2016

3.6-liter Pentastar V-6 adds cooled EGR for model-year 2016

Since its introduction in 2009, the Pentastar V6 lineup has been an enormous success for Fiat Chrysler Automobiles with more than 5 million units sold to date. The Pentastar in 3.6, 3.2 and 3.0-liter (the latter in China only) displacements is offered in everything produced by Chrysler larger than the 200. For the 2016 model year, Chrysler is rolling out the most substantial updates yet for this award-winning engine. At least one aspect of the revised engine points to the upcoming EPA Tier 3 emissions standards.
Most of the revisions to the V6 are pretty straightforward and increasingly common. Two-step variable valve-lift and variable cam-phasing with a range expanded from 50 to 70 degrees will help to reduce pumping losses and contribute to improved torque. Also aiding the torque output is a bump in compression ratio from 10.2 to 11.3:1.

The fuel injectors now have double the holes, going from four to eight for improved atomization of the fuel. However, Chrysler has opted not to follow the latest trend and continues to inject fuel into the ports upstream of the valves rather than directly into the combustion chamber. While this will certainly help keep costs down, during a preview of the engine, FCA powertrain engineering VP Bob Lee explained that they opted to stay with port injection for emissions reasons.

The primary benefit of direct injection is the charge cooling it provides when used in combination with the higher pressures from turbocharging. Conversely, spraying fuel directly into the combustion chamber complicates mixing air and fuel, especially when the engine is cold. This can often lead to higher emissions of particulate matter, aka the soot commonly associated with older diesel engines. Automakers have addressed the problem on diesels with particulate filters that capture the soot and then periodically burn it off at high temperatures.

Beginning in 2017, EPA Tier 3 standards will tighten the limits on particulate emissions for all light duty engines. If you take a look at the area around the tailpipe of many cars with direct injected engines, especially Fords with EcoBoost, you may notice black stains that are typically a sign of particulate emissions. In the coming years, we will like see many, if not all gasoline direct injected engines adopt particulate filters similar to those found on diesels.

Given the experience that many customers have had with mediocre real-world fuel economy on turbocharged GDI engines and rumblings of further adjustments to the way EPA label mileage values are calculated to reflect this, sticking to a normally aspirated engine could work to FCA’s long-run advantage.

Other changes to the Pentastar that will help its emissions performance is the addition of a cooled EGR system and a switch to 100 millijoule high-energy ignition coils. Efficiency will be aided by a two-stage variable displacement oil pump and smaller diameter crankshaft journals for reduced friction. The block casting has been reworked with new ribbing that helps improve noise, vibration and harshness while at the same time reducing the amount of material for lower weight. Despite the 13 pounds added for new hardware like the valve-lift adjusters and EGR, the net weight of the finished engine is only up by two pounds.

Auto stop-start is already included in several Pentastar applications like the Jeep Cherokee and Ram 1500 but it will be standard with all applications of the revised engine. Overall, the revisions to the second-generation Pentastar should boost fuel economy by about six percent. The second-generation Pentastar launches this fall in the Jeep Grand Cherokee and will roll out to other applications over the next year or so.


2016 Chevrolet Volt Officially Rated at 53 Miles Electric Range

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Back in January when Chevrolet first showed off the all-new second-generation Volt, we were told that the electric driving range would be at least 50 miles and the hybrid fuel economy would be about 41 mpg. This morning, they announced the official EPA certified results that would go on the fuel economy label and they beat those estimates. The larger 18.4-kWh battery and more efficient motors are now rated to provide a 53 driving range before the engine fires up. That’s a 40 percent bump from the 37 mile range on the 2015 model (the original 2011 was rated at just 35 miles) Once the battery is depleted (or when its really cold or if you’ve been running on electricity only for more than six weeks) the Volt is rated at 42 mpg combined. Unlike many cars in recent years, GM was always fairly conservative in rating the original Volt and it wasn’t at all unusual for many drivers to meet or exceed the 37 mile driving range on the label. Assuming that GM has done the same this time, most drivers should have little difficulty topping 50 miles but we’ll find out for ourselves in the not too distant future.

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2015 Ford F-150 XLT, 2.7 EcoBoost

2015 Ford F-150 XLT 01

The constant push to one-up the competition while at the same time meet ever tightening fuel economy standards is driving a transformation in America’s most traditional vehicle segment, the full-size pickup truck. This year, perennial market leader Ford has tried to leap-frog the competition with a dramatic shift from the traditional steel body and bed construction to aluminum intensive construction along with an all-new mainstream twin-turbocharged V6 engine. Is it enough to keep the F-150 out in front of the pack? I spent a week driving one in search of some clues.

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