Hybrid Car Review

Comparing diesel to hybrids can be a tricky business. Both types of cars rely on different technology from the norm, but in the coming years, we're going to start hearing more and more about the differences between the two. Hybrid technology has been popular so far in the US, but diesels have become the norm in Europe.

Now that car makers are able to build diesel cars capable of passing the test here in the US, we should start seeing more and more of them available to buy and we should start seeing them grab market share. Consumers are looking for alternatives to plain old gas, especially as the prices climb.

London’s Sunday Times ran a comparison drive with a Toyota Prius and a diesel-powered BMW 5-Series sedan. The BMW 520d had a 2.0-liter diesel engine and regenerative braking (but no heavy duty hybrid features). Instead, it relies on Efficient Dynamics, a term covering several factors to improve fuel efficiency by BMW. These include a smaller engine, better aerodynamics, low rolling resistance tires and a mpg readout on the dashboard.

Both cars were run over a 545 mile trip from London to Geneva (100 miles in strict urban running).

The BMW 520d with Efficient Dynamics came out on top, beating the Prius by 2.2 imperial mpg (about 1.8 mpg US), despite 573 extra pounds of weight.

Although the Prius would have done a lot better if they had done more urban driving rather than 200 miles of autoroute, that doesn't really matter in the long run. If the Prius had edged out the 520d by a few mpg, I would still call it a wash.

A couple more interesting notes about the test: At one point the Prius ran out of gas and the driver actually continued to drive for 2 miles on electric power alone. This is not exactly the best way to drive a hybrid and, in a long 'race,' get good gas mileage.

the petrol engine stopped and for two surreal miles I coasted along on battery power. Only when I approached a long steep uphill stretch did I finally drift to a halt. As I filled the tank I consoled myself with my last chocolate bar.

~from Sunday Times

Some other notes, direct from the Toyota blog, focus in on cost to own. The fact that the BMW is obviously more expensive than the Prius is a silly comparison to make. People buy cars based on what they can afford. And it's not like the Prius comes in at bargain basement prices.

But they do make a good point that the difference in the results aren't all that much, and given the similar prices in diesel and gas, the end cost for fuel was about the same.

But more importantly to some, the emissions are quite different. The Prius is rated at 32 g/km less than the BMW. Other emission comparisons go even worse for the Beemer.

Beyond costs, the Times failed to address the vastly superior performance of the Prius on emissions other than CO2 – you know, those things like particulates and oxides of nitrogen that cause human health issues. Here the Prius shines, with a quarter the particulate level and less than a 10th the NOx of the BMW.

~ from Toyota Blog

We need to become more aware of the differences between diesel and hybrid cars, especially as the EPA begins awarding grants to help clean up old diesels, and new diesels come to market with new, cleaner, engines.

And if cost to drive (i.e. how much you pay for gas/diesel) is important, you may want to start taking a look at all the truck drivers and their complaints and demonstrations against the high cost of diesel.

Diesels do have their advantages, including higher mpg than gas cars. But that is not the end of the story.