The internal combustion engine continues to rule the automotive world despite challenges from power plants that run on batteries and fuel cells.
Eric Fedewa, an analyst with CMS Forecasting Inc. in Northville, Mich., says most of the changes in engines for the 2001 model year are evolutionary. “It’s more in the way of improvements,” Fedewa said.
Michael Heidingsfelder, a partner with the consulting firm of RolandBerger in Troy, Mich., says the cost of these improvements is escalating.
Still, automakers are bringing to showrooms revamped engines that produce more power and torque and pollute less. Many also weigh less thanks to new materials, particularly aluminum, and new computer controls have allowed automakers to engineer hardware such as six-speed transmissions found in European-made luxury cars from Audi and Mercedes-Benz.
On example of the new technology is the 1.7-liter Vtec engine on the 2001 Honda Civic. It’s 8 percent lighter and 7 percent smaller than the 1.6-liter Vtec in the 2000 Civic. But it produces 5 percent better fuel economy and 6 to 13 percent more torque. In addition, the new 1.7-liter engine will be the first ultra-low emission engine distributed in all 50 states, says Andy Boyd, a spokesman for Honda.
Intake ports and combustion chambers were redesigned on the 1.7-liter engine to optimize the air-fuel mix in the cylinder to burn cleanly and quickly, leaving a minimum of unburned hydrocarbons.
The design of the fuel injectors on the 1.7-liter Honda engine also have been improved and a new generation of computer controls helps retard the spark a fraction of a second so the catalytic converter can warm up faster. This cuts hydrocarbon emissions 40 percent in the first few minutes of the vehicle’s operation, when most pollution occurs.
Engineers from DaimlerChrysler also redesigned key components of an engine. The makeover includes new intake and exhaust manifolds on the 2.4-liter engine that is standard in the Dodge Stratus and Chrysler Sebring coupes. The 4-cylinder engine also has balance shafts that help cut down on the vibration and a new engine control unit that improves torque-load management and provides for smoother and faster shifts, said Ann Smith, a Chrysler spokeswoman.
The 4.3-liter aluminum V-8 in the Lexus LS430 produces the power, 290 horsepower, and the torque, 320 foot-pounds, of 5-liter engines, Toyota says.
The 4.3-liter V-8 is one of the first engines with variable valve, which uses a computer chip to make sure the engine’s 32 valves open and close at optimal points throughout the engine’s speed ranges. The VVT-I system eliminates the need to sacrifice torque for top-end horsepower or vice versa, Toyota says, and makes the engine feel more responsive.
Fedewa says he expects other automakers to use VVT-I.
The LS430 also comes with “intuitive powertrain controls,” which basically use a pressure-type sensor to monitor how the driver is pushing the accelerator, along with the vehicle’s speed and engine operating conditions, to adjust torque to driving situations. It downshifts the automatic transmission as the driver applies the brake for a smoother stop.
The 2001 Nissan Pathfinder comes with a new 3.5-liter, dual overhead cam 6-cylinder engine with an aluminum block that can produce 240 horsepower and 265 foot-pounds of torque. The engine, based on Nissan’s VQ engine, which has been among Ward’s Automotive World’s “10 best engines” for six years, doesn’t have to be tuned for 100,000 miles.
Fred Standish, Nissan spokesman, said it was redesigned for a sport-utility vehicle, where the need for mid-speed range torque or pulling power was emphasized to enhance the Pathfinder performance as off-road or pulling a trailer.
The fuel economy of 16 miles per gallon city and 19 m.p.g. highway is the same as that of the engine in the previous Pathfinder despite the horsepower and torque increases, Nissan officials said. Horsepower has been increased 12 percent, to 250, and the torque is up 11 percent, to 240 foot-pounds.
A new spark plug design and exhaust port modification help improve thermal efficiency and fuel economy, Nissan officials said.
The new aluminum block weighs 35 pounds less than the cast-iron block it replaces, and the engine was given new light-weight pistons. A resin engine cover and new platinum tipped spark plugs will last at least 100,000 miles, Standish noted.
In addition, the electronic controls have been revamped to include a new valve-timing control system and new electronically controlled 4-speed automatic transmission that makes a seamless shift.
Nissan engineers have maximized the use of the manifold, which uses an internal valve to vary the length of the intake based on the engine speed.
“The 2001 Pathfinder is deceptively fast and has a true performance engine,” says Bill Kirrane, Nissan general manager.
