2014 Honda Accord Hybrid Touring First Test
Taking the Numbers from a Technical Marvel
Acceleration runs are a part of the standard Motor Trend test regimen. They're supposed to take place with only the driver in the vehicle, dashing down a dragstrip/abandoned runway at wide open throttle. Yet there I was, sitting behind the driver's seat of a 2014 Honda Accord Hybrid Touring idling on the strip. The computer in my lap was hooked into the OBD II port. Testing director Kim Reynolds waited at the wheel. Having patiently entertained many an offbeat test request, Kim and I have become accustomed to sharing cars.
"Maybe we should start farther back?" I relayed to the front row, after I'd noticed Kim had crept up from the usual starting point a smidge.
We weren't on the hot tarmac to confirm the 7.1-second 0-60 mph or 15.6-second quarter-mile times (achieved without me in the back), which is surprisingly not far off the last first-generation Accord Hybrid we tested. (A 2005 model with 253 system hp and weighing 49 pounds less did the deed in 6.9 and 15.4 seconds.) We wanted to find out what the deal was with the engine as the car moseys along in Engine Drive mode. Our drag location isn't infinitely long and we needed to sustain steady highway speeds.
The Accord's new two-motor hybrid system has raised eyebrows and created furrowed brows. Some of the technical details were clear, like how at a brake-specific fuel consumption rate of 214 grams per kW-hr at 2500 rpm and 88.5 lb-ft of torque, the 2.0-liter Atkinson-cycle I-4 is the most thermally efficient, mass-produced, gasoline-fed engine in the world (says Honda's internal testing). The powertrain has three drive modes: EV Drive, Hybrid Drive, and Engine Drive. There are two electric motors but only the one with 166 hp is responsible for turning the drive wheels. The other acts as a generator (spun by the engine) to help the traction motor.
Between the powertrain's introduction and now, it became fashionable to claim this car and its plug-in hybrid sibling have no transmission. But that doesn't tell the whole story. According to the folks who developed it, the Accord Hybrid has an "electric coupled continuously variable transmission." Kim made the point that you can't leave the term alone without attempting an explanation. The CVT consists of three shafts (like many other transmissions), two oil pumps, a torque-limiting mechanism, a lockup clutch, and the two e-motors mentioned earlier. There's cleverness here: There are no pulleys, belts, chains, or planetary gearsets facilitating the gearing manipulation associated with CVTs, only a series of mechanical connections with predetermined reductions. Offsetting the lack of ultimate gearing adjustability (via a true CVT) are generous savings in complexity and friction. Honda estimates its e-CVT will be 2-3 percent more efficient than a comparable planetary setup.
Back in the Accord Hybrid's back seat, which is very comfortable as long as you're not in the middle, I snapped to attention as Kim started his first run. A few seconds before his start, the engine had been chugging away to charge the air-cooled lithium-ion battery in stationary Hybrid Drive, allowing Kim to experiment with brake torqueing despite the lack of a tachometer. But right before setting off, the 2.0-liter cut out without warning and the car went back to EV Drive status. Forget about holding it at WOT at zero mph.
Nevertheless, Kim hadn't forgotten how to mash the gas medal. About a millisecond after the traction motor (226 lb-ft of torque from zero rpm) pitched the car on its hindquarters, the engine pounced into action to assist the battery and e-motor. My computer showed the engine peaked at 6218 rpm by the time the car was at 46 mph and clung to around 6200 rpm approaching 80 mph, registering a high of 6250. Of course it likes these revolutions per minute; the 2.0-liter's peak power output of 141 hp comes at 6200. The revs drop off at speeds greater than 80 mph, deciding that 5900 rpm is more comfortable. As Kim coasted to a stop, the revs plunged to a less stressful and less noisy 1500 rpm, holding there from 64 mph downward before stepping down to 1200 rpm at 25 mph.
But Kim and I wanted to learn more about Engine Drive. Here, the e-CVT lockup clutch's only job is to direct engine output straight to the wheels for efficient, part-load high-speed cruising through an overdrive-like single gear reduction, meaning there should be an unmistakable mathematical trend in the I-4's rpm vs. different miles per hour. What is that gear?
"Let's go for 50 mph first," I said.
Kim obliged with a wallop of the accelerator pedal, flipping my laptop's lid toward its closed position again. The Accord Hybrid leaped off in Hybrid Drive and the engine angrily stormed to 5300 rpm as if attempting another full-acceleration sprint test. Then it stopped. Kim has lifted and is barely grazing the throttle to maintain 50 mph. A second later, the revs have dropped to 4400. Another second passes and it's plummeted to 1850 rpm having switched to Engine Drive, where the gas engine sweetly hummed along for the next 30 seconds.
We repeated our inquest at 60 and 70 mph. Knowing the tire diameter and axle ratio, and now with the Engine Drive's realized gear ratio in mind (about 0.8:1), we can predict the rpm at both speeds. The OBD II readout proved us correct: 2200 rpm at 60 mph and 2550 at 70. The hazily named "electric coupled CVT" is like three transmissions. The EV and Engine Drive have their own direct-drive gear reductions. Hybrid Drive piggybacks off the EV Drive reduction, except with the added element of the engine firing away at whichever obligation-free rpm it determines is best in order to stimulate the generator. Whether you believe these are transmissions or not is apparently a matter of semantics.
Off the dragstrip, and with the hybrid system details out of sight and out of mind, the car drives brilliantly. I've listed observed highway fuel economy numbers at the article's end over a roundabout 1850-mile drive from San Antonio, Texas, back to MT Central near LAX by way of south Colorado. It's quieter than its I-4 and V-6 counterparts with a deftly controlled ride that makes long drives easy on the driver. When not blasting along on the highway, the car loves pulsing into EV Drive at lower speeds and long downhill stretches, slipping as much battery power into trips as possible. The brake pedal feels oddly stiff at the top of travel initially -- it uses an electric servo brake system derived from the Fit EV for greater braking regeneration -- but I got used to it quickly.
On the figure eight, it handled better than expected for a sedan of its purpose, posting a comparable lap to a Toyota Camry Hybrid and Volkswagen Passat TDI. Amplitude-reactive shocks from Showa help on the streets and on the track, but the steering feels number than the non-hybrid Accords. You can't select your own "gear," so in order to get the best exit out of the figure eight's turns, you go for full gas pedal depression extremely early (near the physical apex, which is basically never an option). Asking for full power early in the turn accounts for the response delay as the engine spins up, and you unwind the steering wheel on exit as the front tires fight to keep the line. It's kind of shocking how effective this method was.
Less shocking is that Honda anticipates sales to improve over the 2005-2007 Accord Hybrid's (less than 30,000 total). Considering the new model's renewed technological focus and 50/45/47 mpg city/highway/combined EPA ratings (with the 50 being the headline grabber), that shouldn't be too difficult.
Honda Accord Hybrid fuel economySan Antonio, TX to Vega, TX -- 502 miles, 39.2 mpg (mostly at 75 mph)
Vega, TX to Alamosa, CO -- 429 miles, 37.7 mpg (climbing elevation, 65-70 mph)
Alamosa, CO to Kingman, AZ -- 596 miles, 45.8 mpg (a lot of 65-mph driving)
Kingman, AZ to Los Angeles, CA -- 323 miles, 44.0 mpg (mostly at 70 mph)
Total -- 1850 miles, 41.5 mpg, 63 mph average speed
|2014 Honda Accord Hybrid Touring|
|PRICE AS TESTED||$35,695|
|VEHICLE LAYOUT||Front-engine, FWD, 5-pass, 4-door sedan|
|ENGINE||2.0L/141-hp/122-lb-ft Atkinson-cycle DOHC 16-valve I-4 plus 166-hp/226-lb-ft electric motor; 196 hp comb|
|TRANSMISSION||Cont. variable auto|
|CURB WEIGHT (F/R DIST)||3535 lb (59/41%)|
|LENGTH x WIDTH x HEIGHT||192.2 x 72.8 x 57.5 in|
|0-60 MPH||7.1 sec|
|QUARTER MILE||15.6 sec @ 90.0 mph|
|BRAKING, 60-0 MPH||118 ft|
|LATERAL ACCELERATION||0.80 g (avg)|
|MT FIGURE EIGHT||28.1 sec @ 0.59 g (avg)|
|EPA CITY/HWY FUEL ECON||50/45 mpg|
|ENERGY CONS., CITY/HWY||67/75 kW-hrs/100 miles|
|CO2 EMISSIONS||0.41 lb/mile|