Driving Toyota's Plug-in Prius
By Bill Moore
Picture this. In the background is majestic Mount Fuji. In the foreground are six Priuses that represent the future of Toyota Motors and, most likely, the auto industry.
I and a handful of high-profile American automotive journalists are about to experience the ride of a lifetime: we're about to get behind the wheel of Toyota's internally developed plug-in hybrids.
For many of us who not only have been watching but also faming the flames for electric plug-in hybrids, it may seem that the big auto companies have only lately and reluctantly come to the dance. But as I am about to learn during our visit to Toyota's proving grounds, Japan's largest carmaker has been quietly experimenting with PHEV technology for much longer than many of us have imagined.
Our trip to Higashi Fuji started early in the morning with a 5 AM breakfast call, a walk to the near-by Tokyo central train station from which issues gleaming white bullet trains every few minutes and commuter trains every few seconds. As I am writing this, the trains are less than 100 meters from my 3rd floor room in the Four Seasons at Marunouchi. Gratefully, the sound proofing in the room is excellent.
Higashi Fuji is a one hour bullet train ride south of Tokyo, plus an hour-long bus ride that winds over narrow roads, through a string of Japanese towns and villages. Once at the Toyota proving grounds we must leave our cameras behind -- hence there are no photos of the plug-in Priuses we test drove or the FCHV (fuel cell hybrid vehicle) that was also on hand for us to experience.
After the pre-requisite company presentations, including a glitzy, but informative video, we piled onto a second bus -- thus insuring that no cameras would be present -- and wound our way through a maze of buildings and garages, eventually arriving at the center of one of the complex's two test tracks. There Toyota had set up two short driving courses, each adjacent to the other. The nearer course would be for the plug-in Prius drives, while the outer loop would be for the FCHV.
The company had set up a tent with folding chairs for the gathered journalists who report for the likes of the Wall Street Journal, Road and Track, LA Times, Edmunds, the New York Times... and of course EV World. But since the weather was fine and the six flower and bird-emblazoned Priuses beckoned, no one followed the script. Instead, we piled off the bus and made a bee-line to the neatly lined-up cars to check them over.
Apart from their curiously Zen-like applique of flowers morphing into birds atop pearlescent gray paint, the cars are your standard Japanese, right-hand drive models; albeit the computer display screen offers at least one new wrinkle that indicates one's driving performance in both EV and hybrid mode.
We had learned the previous day at Toyota City near Nagoya, that in order to experiment with the plug-in hybrid concept, company engineers had chosen to simply add a spare Prius NiMH battery to each vehicle, giving the car a total of 2.6 kWh of electric power capacity or enough to propel the car in electric-only mode between 6-7 km, an admittedly modest distance. Like the grassroots plug-in experimenters and converters in the U.S. and Europe, Toyota engineers also chose to locate the additional battery pack in the spare tire well below the rear cargo deck, a move that Toyota itself has criticized as being unsafe since it is outside the vehicle crush zone.
The other contradictory item of note is Toyota's assertion that the Priuses being converted by their owners are showing increased smog emissions over the standard, in-warranty vehicle because the catalytic converter doesn't have a chance to be warmed up by the engine once the car slips back into hybrid mode. It turns out that there is a vacuum bottle of sorts on the Prius that stores a heated fluid for up to three days and is used to pre-warm the converter, thus reducing cold start emissions. Presumably, it should also work on owner-converted models, assuming the plug-in converters have figured out how to hack that piece of the car's code, a topic I'll return to below.
Back on the track, Toyota organizers gradually regained control and gathered us around to brief us in the plans for the drive. We'd be paired together, two journalist per vehicle, and be required to wear helmets. Each of us would be given just one pass around the make-shift track in both the Prius and the FCEV. We could not exceed 70 km/hr.
I was assigned to car number two and offered the first drive. With Yoshikazu Tanaka seated next to me, I turned on the car and set-off in EV-only mode. Our assignment was to drive the first half of the course on battery only, followed by harder driving that engaged the IC engine. I found that I could maintain the equivalent of about 55 mph in EV mode, which the Prius has always been capable -- mechanically -- of achieving. However, for reasons of battery longevity, it is electronically prohibited from going above 34 mph in the standard model. [See 3-Speed Prius].
While critics have sneered at Toyota's admittedly modest claims for its PHEV technology, which falls well short of the electric-only range being pursued by General Motors -- 7-8 km versus 40 miles (64km), it likes to point out that it has, in fact, real working vehicles on the road. I counted a dozen during my visit to both Toyota City outside of Nagoya and the Higashi Fuji complex. How many operational Volts are there, they ask?
According to Yoshitaka Asakura, Toyota's hybrid program manager, the company began exploring the plug-in hybrid concept as long as three years ago, and from journalist test drives around the center on their sprawling test track, the company is still tweaking the system.
While my all-too-brief run was relatively uneventful, other journalists weren't as fortunate. Apparently the number 3 car had something of a software glitch. If the driver started off quickly, immediately engaging the IC engine, he would have to slow the car to around 20 mph for it to slip back into EV-only mode. The LA Times' Martin Zimmerman found this problematic, noting that it would make the car's electric-only feature useless on the mean streets -- and freeways -- of his adopted city. He wondered why the car didn't drop back into electric car mode more quickly after hard acceleration.
A couple other experienced automotive journalists also noted the same problem, so Mr. Asakura, who was overseeing the event, agreed to let them try a different car, which apparently did respond properly. The consensus among Toyota's engineering staff was that the hard acceleration at the start may have drained the battery just enough so the car needed a run in hybrid mode longer in order to recharge the pack.
Obviously, this is just one of the technical issues that must be resolved before commercialization and, no doubt, has led Toyota to adapt a cautious approach to plug-in technology. If after three years of experimentation, including intimate familiarity with their own computer control codes, the world leader in hybrid car technology is still learning, it suggests this may be a bit harder nut to crack than many of us had assumed.
On the question of those codes, I learned from Bill Reinert, Toyota USA's National Alternative Vehicles program manager, that from the 2007 model onward, it's going to be a lot harder for experimenters to hack into Toyota's control software. The catalyst for tightening up of what has been, up until now, pretty open code has to do with the implementation of OBD III (on-board diagnostics 3), a regulation from the EPA that requires new, more complex emissions data reporting aboard each car. While unrelated to the activities of the plug-in hackers, the change will make it harder for experimenters to read the vehicle's control codes.
The answer to the burning question of why Toyota is, after three years of testing, continuing to use NiMH batteries instead of lithium ion, which is what many of the grassroots converters are offering, appears to be directly related to the company's policy of utilizing its own internal resources, including battery technology, for advanced product development, in contrast to GM's partnering with outside venders like A123, JCS and Compact Power. Since its lithium ion batteries aren't presently up to its own stringent standards, it opted to utilize its well-understood NiMH system; and for testing purposes, this approach seems to be a pretty reasonable one. Besides, the software has been adapted to simulate lithium batteries, so when Toyota's own cells do become available, it can replace the NiMH without having to rewrite the code.
After the Prius run, I got to drive the latest iteration of the FCHV, a hydrogen fuel cell SUV based on the Highlander (Kluger in Japan). And as in the past, you cannot but be impressed by the transparency of this machine. Toyota may still be learning on the PHEV Prius, but it clearly has its act together on this vehicle, one of which recently traveled on a single fueling of hydrogen from Osaka to Tokyo, a distance of just under 350 miles.
This fuel cell and battery powered electric vehicle offers all the amenities and performance of the conventional Highlander/Kluger with none of the tailpipe emissions or dependency on fossil fuels. In fact, one of the interesting facts we learned during out visit to Toyota City is that the hydrogen it uses for its research program comes as the waste by-product of another company's caustic soda manufacturing process. It is trucked in on a daily basis and compressed for use in the company's fuel cell cars and bus.
And yet for all the FCHV's advances, it seems everyone at Toyota recognizes that fuel cells remain a distant dream. Even if Toyota succeeds in lowering costs to 1/100th of their current level, while improving the durability of the stacks to the equivalent of 150,000 miles, the problem of infrastructure and sustainable hydrogen production present daunting obstacles to what Toyota President Katsuaki Watanabe told me is his personal, "eco-car" dream.
While the FCHV may not be that vehicle, it strongly suggests the direction in which the dream lies. In the interim, the company recognizes the important role of plug-in hybrids in helping reach that goal. That, in itself, is an important milestone.
blog comments powered by Disqus