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Toyota's Hybrid Prius Roadtest Prius Economy Falls Way Short |
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Hybrid Technology Impressive, But Fuel Efficiency Exaggerated Sadly, This Is Typical Of Car Industry’s Economy Claims 41 mpg would be impressive; so why claim 65.7 mpg? When I drove the new Toyota Prius petrol/electric hybrid at its launch in Florence late last year, I raved about this fantastic engineering achievement. The new Prius had vastly improved performance compared to the car it replaced, look great, had plenty of room for 5 and their luggage, and was dripping with the latest technology. The computer power which managed and manipulated the petrol and electric engines was mind-boggling. I was so impressed that I awarded the car my maximum rating of 5 stars out of 5. But there was a proviso. “I reserve the right to downgrade it if fuel consumption doesn’t come up to scratch when I have the car for an extended road test,” I said. Well, it doesn’t and I hereby downgrade the Prius to 3 stars out of 5. This habit of car companies to grossly overestimate fuel economy has become a fetish of mine. Routine Ripoff I published research in November 2002 which pointed out that car manufacturers were routinely ripping off buyers by claiming fuel economy for their cars which bore little relation to reality, and which often exaggerated actual consumption by 25% or more. Some failed by over 30%. Since then, my road test data of a wide range of cars, including the most up to date new common rail diesels, showed a similar range of exaggeration. The original Prius was the most egregious example and the new one is even more so. I had high hopes of the latest Prius, despite the fact that the original dumpy little car failed so miserably to come up to scratch. That car returned a pathetic average 38.1 miles per gallon (6.2 litres per 100 kms) compared with Toyota’s claim of 57.6 mpg/4.1 litres. That’s a massive under-achievement of 33.9%. New Prius Fails By More The new Prius claims even better fuel economy–65.7 mpg/3.6 litres–but manages to fall short by an even bigger margin. I managed 40.6 mpg/5.8 litres over about 350 miles, that’s 38% short of the claim. A recent test by Britain’s Autocar magazine achieved an average 41.7 mpg. I wasn’t driving the car hard, and most of the route was rolling through the Sussex countryside at between 50 and 60 mph with some motorways and a little bit of town action. After my report on the original Prius, Toyota said that the poor figures were due to the fact that most of my driving then was on motorways. The car was not at its best on motorways. Of course you can rest assured that this disclaimer wasn’t transmitted to any potential Prius buyers. response letter from Toyota |
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Something Bad Happening? E.U Can’t Be Far Away There is though an obvious reason for this discrepancy, and you won’t be surprised to learn that it is all in the small print, and it involves the European Union. In a recent advertisement in the Daily Telegraph, Toyota made its claim that the Prius would achieve 65.7 mpg. But there was a little asterisk attached to the figure, which was for the so-called combined cycle, which I take to mean average. The asterisk pointed out that “Fuel consumption figures quoted are determined according to EC Directive 1999/100/EC”. Perfectly Comparable Garbage This is the cosy little arrangement with the E.U. where all the car companies agree to measure the fuel efficiency of their cars using the same methods, on a test-bed in a laboratory. This has the advantage of making all the data perfectly comparable. Unfortunately, it also means that the figures have absolutely no relation to on-the-road reality. This also means that CO2 figures used to determine individual tax liabilities for company car drivers are also an underestimate. (Just wait for the furore when leftist politicians figure this out.) Added to the fact that most road tests done by journalists don’t involve measuring fuel used, because the car companies deliver the vehicles with a full tank of petrol, and you can see why the cosy little arrangement has so far been allowed to continue. Unnecessary In a way though, this is an unnecessary little subterfuge. For the original Prius to manage 38.1 mpg was really pretty good. The bigger and superbly equipped Mark II Prius gave me an average 40.6 mpg. That’s impressive, so why the pretence of even better economy? It just isn’t necessary. Which brings me back to driving the new Prius. Just Try And Steal This Punk, Go On, Make My Day One of the many benefits of owning this high-tech machine is the fact that it will never be stolen. It is so complicated to start up that it might even be worth leaving it parked in some notorious neighbourhood just to see the expressions on the faces of the greedy morons who steal cars for a living. They will fail, because you have to depress the brake pedal, and turn the ignition. Nothing happens, but the dashboard lights will go on as the silent electric motor starts. There is a delay of a few seconds, and the petrol engine will finally start to fire when you attempt to pull away. Putting the car into “drive” using the little dashboard mounted automatic gearbox is also less than intuitive. When I suggested that my wife Kathy take the car for work one day, she demurred when I tried to explain the procedure. Needless to say, it becomes second nature pretty soon. Electric Only At Slow Speeds At low speeds, the car is powered purely by its electric motor and its petrol engine is switched off. As speed increases, the petrol engine automatically starts to produce more of the power required. When decelerating or braking, the electric motor acts as a generator, controlling power distribution to the wheels. The regenerative braking system recovers the kinetic energy and stores it in the battery. On the road the car performs adequately. Toyota says it has the performance of conventional 2.0 litre turbo diesel engine, with its 1.5 litre, 76 bhp petrol motor and 50 kw, 67 bhp electric motor. The transmission noise is a little weird, as the computer collaborates between electric and petrol mode for the most efficient solution. It sounds like a Constantly Variable Automatic (CVT) but it’s not. Under heavy acceleration the engine sounds a bit rough and intrusive, but soon settles down. Screen Monitors Interaction A screen on the dashboard shows in precise detail when the car is using electric or petrol power, when the battery is charging or performing. The screen also shows the exact, current fuel economy and dashes about between 15 and 97 mpg. The speedometer is digital and set high at the front of the dashboard. There is not a rev counter. Maybe there should be two. Going down hill you can induce engine breaking by selecting “B” drive mode. This will not only slow the car, but sets off a healthy looking charging sequence for the battery. Disconcerting It’s a bit disconcerting in traffic when the engine turns off when you stop. But the petrol engine always started instantly when you put your foot down. This will save you money though, and cut down on emissions in town centres. Entertainment and air conditioning controls are on a touch screen, which works effectively. The boot is adequate and passed my golf bag test. The rear seats fold and passed my mountain bike, fully assembled, test. The Prius comes in three versions, all with the same power plants and automatic gearbox. The base T3 has all the computer assisted braking and driving electronics, and electric windows. Electronic air conditioning, six speaker audio, touch screen and the full range of airbags. The T4 adds cruise control, fog lamps and a six-disc CD player. The top-of-range T Spirit has sat-nav and blue-tooth compatible communications. Toyota reminds us that Prius means “ahead of its time” in Latin. What will they call it when it actually fulfils all its promises? I’d better find out the Latin for “does what it says on the can”. Neil Winton, March, 2004
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