Feature > New Vehicle Reviews
Ford Escape Hybrid
Most Unusual: Ford sends the first gas-electric SUV to market. Does the Escape Hybrid hint at the future of 4WD?
text and photography by Rob Reaser
The search for alternatives to gasoline for powering internal combustion engines is age old. It may have started when some ‘shine runner dumped a load of whiskey in his tank, figuring since his corn squeezin’s could fire up a Saturday night hoe-down, it was plenty potent to light a right proper fire in ol’ Betsy.
He may have actually been on to something, since today, ethanol (aka “corn juice”) is standard fare in many fuel blends.
Increasingly stringent CAFE standards and assorted Federal, state and local regs have forced auto manufacturers’ to develop vehicles with higher fuel economies and lower emissions. As a result, automobiles are moving towards lower fuel operating costs and reduced emissions. Many alternative fuel and alternative power options have been tossed on the table, including solar, battery, hydrogen, and, yes, plant power.
When the optional navigation/Audiophile stereo system is ordered, the display screen located in the center console can present a real-time powertrain energy flow diagram. It shows when and where power is distributed among the engine, electric motor and battery pack.
Since ours is a magazine which keeps its eye on things four wheel drive, let’s see where that leaves us. There are trucks that run on compressed natural gas and engines with multiple displacement (some cylinders shut down when the load drops below a certain level). There are flex-fuel trucks, which can operate on blends of gasoline/ethanol or straight gasoline, or CNG and gasoline. Recently DaimlerChrysler announced that it is moving towards developing biomass-based fuel (plant stuff) as an alternative to power diesel engines.
While some of these technological advancements are still in the development stages, gas-electric hybrids have already hit the market. Ford was the first to come out with a gas-electric hybrid 4WD, the Escape Hybrid, based on their Escape SUV. This year GM is also offering a gas-electric hybrid version of its 1500 Silverado extended cab (although available only in limited quantities in CA, WA and OR ). Expect a full review of this model when they become available nationwide.
In the meantime, we were able to put our paws on an Escape Hybrid earlier this year and give it a good wringing out. One thing’s for sure...it’s a different kind of beastie.
The Escape Hybrid’s (hereafter referred to as “the Hybrid”) powertrain foundation is a 2.3L four-cylinder engine which works in unison with a 70 kW electric traction motor. Between the two, the Hybrid can run on pure electric power, pure gasoline power, or a combination of both.
Underneath the carpet you’ll find the Hybrid’s battery pack serving as the rear cargo floor. This 330-volt assembly is comprised of 250 D-size cells needed to power the vehicle’s electric motor. Cooling and heating systems are integrated to maintain optimal operating temperatures.
The four-cylinder represents a variation of the Escape’s standard Duratec 23 2.3L engine in that it uses an Atkinson cycle to provide a 4% increase in fuel efficiency. Never heard of an Atkinson cycle engine before? Don’t feel left out, most folks haven’t.
This engine design was first presented by James Atkinson in 1882 as a more fuel efficient alternative to the conventional four-stroke engine. By using additional linkage between the crankshaft and the connecting rod, one revolution of the crankshaft in Atkinson’s engine design delivers all four strokes of the combustion process (intake, compression, power stroke, exhaust). But there’s more to it than that. In contrast to standard four-stroke engines, the Atkinson cycle keeps the intake valve open for a short time after the compression stroke begins, allowing part of the air/fuel mixture to be pushed back into the induction system. This effectively increases the power stroke and permits a more complete extraction of energy from the air/fuel mixture, hence the 4% increase in fuel efficiency.
You can’t tell a whole lot from peering under the Escape Hybrid’s hood, but there’s a lot of weird stuff going on here. Power comes from a 2.3L Atkinson cycle gas engine supplemented by a permanent-magnet electric traction motor. Combined, the total available output comes to 155 horsepower.
While definitely an improvement in fuel efficiency, there is a downside to the Atkinson cycle — that being a reduction in low-end torque. Enter the electric motor. This is a permanent-magnet traction motor with a 70 kW (kilowatt) rating, which Ford explains is equivalent to 94 horsepower. The electric motor has two functions: assist the gas engine when additional power is needed (such as in quick acceleration or in meeting high load demands), and power the vehicle by itself during conditions of low speeds and low load demands.
Another one of the fuel-saving characteristics of the Hybrid is its ability to completely shut down the gas engine when it’s not needed, such as in stop-and-go city driving. Come to a stop or coast and the gas engine goes silent. It’s a bit unnerving at first, sitting at a traffic light with your engine off and the vehicle completely quiet, but you soon get used to it.
From the driver’s seat you have little trouble figuring out that you’re not sitting in a big SUV. Still, front seating is comfortable, and the footwell area actually seems as expansive as some bigger SUVs. The center console contains large cup holders, a storage compartment, 12-volt outlet and an available 110-volt outlet.
From a stop, the Hybrid can use its electric motor as its sole means of propulsion up to around 25 mph, depending on the load (i.e. acceleration rate). When more power is needed, a strong starter motor reactivates the gas engine. This occurs in a remarkably quick 400 milliseconds. Thus, the transition from dead-stop or electric power to gas power is actually seamless.
Naturally, an electric motor that operates independently of a gas engine requires some source of energy. In the Hybrid this means batteries — and lots of them. The Hybrid uses a large battery pack that actually is the rear cargo floor of the vehicle. The pack is a 330-volt unit (so don’t go poking a screwdriver around this thing!) that is made up of a bank of 250 D-sized cells. Due to the thermal sensitivity of batteries, an electric heater and a forced-air cooling system are used to keep the battery pack within optimal operating temperatures.
The instrument cluster is spartan compared to many SUVs. The white-face gauges are easy to read. Note the gauge on the far left which indicates the battery pack’s charge and assist levels. The “green zone” on the tachometer lets you know when the vehicle is running exclusively on electric power — just in case you miss the lack of engine hum.
Batteries have to be recharged. The old notion of recharging electric vehicles by plugging them into an AC source doesn’t apply here. The Hybrid gets the job done via regenerative braking and the aforementioned starting motor. Here’s how it works.
When the driver lets off of the accelerator pedal, the electric drive motor slows the Hybrid — sort of like compression braking. When the brake pedal is depressed, the motor is instructed to reduce driveline rotation even more to slow the vehicle. This transfer of energy from momentum to electricity in the drive motor allows the motor-generator to recharge the batteries rather than waste the momentum energy as heat dissipating through the brakes. In fact, it is only when the driver demands more braking force than what the drive motor can supply that the system even engages the front and rear disc brakes.
That’s cool engineering.
There’s nothing exceptionally complicated about the Hybrid’s front suspension. Independent articulation comes from MacPherson struts with lower control arms and coil springs. A stabilizer bar contributes to the vehicle’s pleasing on-road manners.
Now that you have the gist of how the Escape Hybrid earns its stunning 36/31 city/highway mpg rating, the question is, what’s it like?
For starters, the darn thing sounds like it’s going to blow up whenever you stand on the throttle. To be honest, the vehicle’s sound and feel, coupled with the drivetrain engineering at work beneath the sheetmetal, reminds me of one of those old friction motor toys we used to play with as kids. You know the ones — you’d wind them up by pushing the toy across the floor repeatedly until the motor whined like a tea kettle and sparked like a Roman candle. Also, in spite of what Ford says, it doesn’t feel to me as if the Hybrid offers performance similar to that of a V6 engine. Still, to be fair, I have to evaluate this product in the context of the engineering for which it was designed — specifically, fuel economy. So with that caveat, I must say that the Hybrid’s powertrain does quite well. You won’t win any drag races, but who cares when you can go up to 400 miles on a single 15-gallon tank of gas?
The main reason the Hybrid reminds me of a friction motor toy is the transmission, or more specifically, the sound of the tranny. To better accommodate the integral traction motor and power-management electronics, Ford uses a continuously variable tranny with a planetary gear set rather than a conventional auto slushbox. It’s kind of like what you find in an automatic ATV. Peak performance and efficiency is maintained throughout the power band, and, because it’s not hydraulically governed by a valve body, there are no shift “steps.” One thing’s for sure...it’s smooth and steady from start to full-boogie.
There’s not a lot of get-down-and-boogie room in the back of the Escape Hybrid, but neither is space and comfort lacking for a vehicle of this size. When the 60/40 seatbacks are folded down, the rear cargo area is expanded to 65.5 cubic feet.
Four wheel-drive Hybrid models are equipped with the new Intelligent 4WD System. This is an electronically controlled system that’s completely automatic, meaning you have to do absolutely nothing to enjoy its benefits — it’s there all the time. By monitoring sensor inputs from the accelerator pedal and all four wheels, the computer can determine how much torque the rear wheels need to maintain vehicle control and forward movement. So, when the front wheels (normal operating mode) slip, a computer-controlled clutch sends power to the rear wheels. During my testing period I was fortunate to have some really miserable winter weather, complete with ice and frozen slush. Never did I have a traction problem. The system worked so seamlessly I never could detect when 4WD engaged.
Obviously, the Escape Hybrid is not your first choice for a rough-and-tumble trail rig, or a 4x4 for the farm or job site. If, on the other hand, you want a capable backroads cruiser that smiles kindly on urban street running in terms of fuel efficiency, the Hybrid deserves your own test drive.
No live axle here, however, the independent nature of the Hybrid’s rear suspension combined with its 4WD capabilities makes this an SUV you don’t have to be afraid to take off-highway (providing you’ve got some decent treads).