(DEARBORN MI, Oct. 28 2008) The 2010 Ford Fusion and Mercury Milan will be the first significant refresh of the mid-sized sedans since their 2005 debut and fuel efficiency is a major component of the upgrades. For the first time, Ford is building a hybrid version of the mainstream sedans and city fuel economy is expected to beat the current class leader, the Toyota Camry hybrid by at least 5 mpg. In the non-hybrid lineup, all the four and six cylinder engines will be paired up with six speed transmissions.

One thing Ford doesn't plan on adding to the Fusion and Milan anytime soon is diesel engines. Barb Samardzich Ford VP for Global Powertrains explained that "We don't want our sustainability strategy to be a public affairs exercise." Ford's plan is provide "affordable fuel economy for millions" through maximizing the efficiency of conventional engines and introducing technologies like EcoBoost (down-sized gasoline turbocharged direct injected) engines as well as more hybrid vehicles.

2.5L four cylinder

As US gas prices spiked to $4 per gallon and above in 2008, Ford along with every other carmaker was caught flat-footed by a sudden and rapid shift away from V8 engines toward smaller four and six cylinder engines. In March 2008, V8 engines accounted for 44 percent of Ford's North American production volume while four cylinder engines made up 25 percent. By August that had been almost reversed to 22 percent V8 and 39 percent four cylinder.

The new 2.5L four cylinder that first appeared in the 2009 Escape last spring will move into the revamped Fusion for 2010, mated to either of a pair of six speed transmissions with or without a clutch pedal. Compared to the 2.3L engine in the current Fusion, power goes up from 161 hp to 175 hp and torque increased 16 lb-ft to 172.

Ford's 6F35 transmission.

Most of the engine has been redesigned with better flow through the cylinder head and variable phasing on the intake camshaft. The cylinder block, pistons, crankshaft, and connecting rods are stiffer for reduced vibration and better thermodynamic efficiency. Ford has added adaptive knock control, which allows the engine management system to optimize the fuel delivery for minimal consumption without triggering damaging combustion detonation.

Ford has also implemented aggressive deceleration fuel cut off that shuts off gas flow when the accelerator is released. However, simply shutting off fuel delivery abruptly causes engine shake and bumps during deceleration. Instead, the Ford powertrain engineers have used a torque-based control model. When deceleration is detected, the engine management system tries to ramp down the torque output to zero in a smooth, seamless manner. The fuel injection pulses are gradually reduced in conjunction with throttle and camshaft management in order to track a desired torque output. Similarly, the fuel flow is ramped back up when the throttle is reapplied. The fuel cutoff system is responsible for a 1 percent fuel economy improvement.

The combination of design changes has improved overall fuel efficiency by about 10 percent and is expected to give the four cylinder Fusion a 2 mpg highway advantage over the Toyota Camry and 3 mpg over the Honda Accord. At the same time, acceleration is improved to 9.5 seconds for the 0-60 mph run. Judging by the Escape the four cylinder, the Fusion should also have a much more refined character than the 2009 model.

3.0L V6

The V6 Fusion also gets a major upgrade for 2010. In addition to the changes that were implemented on the 2009 Escape, the new Fusion V6 now has flex fuel capability, allowing it to run on any combination of gasoline or E85. The cylinder heads get new tougher valve seats and higher flow fuel injectors to accommodate running on ethanol. Like the four cylinder the V6 gets the deceleration fuel cutoff based on an engine torque control strategy.

The V6 also gets variable cam phasing although Ford has a new mechanism for actually adjusting the cam shaft angle. Cam phasing systems on engines are typically actuated by means of hydraulic fluid pressure. This usually requires a higher capacity oil pump, which increases the parasitic load on the engine. The Ford system called Cam Torque Actuated (CTA) iVCT was developed by the automaker with Borg-Warner. The two companies devised the system to use the torsional reaction forces inherent in the camshaft to generate the hydraulic pressure needed to adjust the phasing. As the camshafts turn and the lobes run up against the valves the shaft twists and internal forces are generated. As the lobe passes the valve, that force is released.

The 2010 Fusion

A mechanism mounted on the end of camshaft includes check valves and an electronically controlled spool valve to manage oil flow into and out of a pair of chambers that control the cam phasing. By timing the position of the spool valve with the position of the camshaft, the camshaft angle can be adjusted with less pressure from the main oil pump. As a result, the same oil pump used with the variable cam timing is sufficient - improving efficiency. According to the Ford engineers on hand, the CTA system improves mileage by 0.8 percent.

The new system also is able to adjust the cam timing at lower speeds, as well as more responding more rapidly because more pressure is available to the adjustment mechanism. The result is that the system can generate more 40 degrees more camshaft adjustment and 35 lb-ft more torque output at 1,500 rpm. This system debuted on the Escape and so far Ford is the only carmaker to implement it.

Hybrid

The 2010 Fusion and Milan are the second platform to get hybrid drivetrains after the Escape and Mariner. While the hybrid hardware of the Escape has remained largely unchanged since its introduction in 2004, the Fusion gets a significantly upgraded version. The basic layout remains the same with a power-splitting planetary gear variable ratio transmission blending drive torque from the engine and electric motor.

However, Ford has made some significant changes to dramatically improve the efficiency. The heart of a hybrid system is the battery. The new battery pack still uses nickel metal hydride cells, but the newer chemistry now provides 20 percent more power per cell than those in the Escape. The Escape pack was produced entirely by Sanyo while the new Fusion pack has been integrated by Delphi using Sanyo cells. The battery management electronics and software for the Fusion pack have been developed in-house by Ford. The new pack is now significantly lighter, weighing in at just 145 lbs, 23 percent less than the Escape. The pack still has a capacity of 1.3 kWh but the package volume is now 30 percent smaller.

While increasing the voltage will increase the power available in the electric drive system, higher voltage increases losses in the electronics due to resistance and heat build up. Reducing the voltage increases the efficiency of the electric drive system. So Ford has reduced the nominal voltage of the battery pack to 275V. However, the system still needs power to provide adequate performance. To overcome this Ford has developed a Variable Voltage Controller (VVC). Under light load conditions, the electric drive and power electronics operate at the new lower voltage levels. When more power is needed for acceleration, the VVC steps up the voltage to provide extra power on demand.

In the hybrid transmission, the motor and generator are the same size as those in the Escape. But the components are now significantly stronger. The motor output has increased from 70 to 93 kW while the generator has gone from 45 to 70 kW. That extra power means that the hybrid now shuts down the engine twice as often as in the Escape and the Fusion can run under electric drive much more often. The original Escape hybrid could drive in electric mode at up to 24 mph. The upgraded 2009 model bumped that up to 40 mph largely through control software upgrades. The Fusion and Milan are able to cruise on battery power alone at up to 47 mph.

Like the new Escape, the 2.5L four cylinder running with an Atkinson cycle is paired up with the hybrid drive. In the Fusion the engine will generate 153 hp and 136 lb-ft of torque. The Fusion and Milan are the first Fords to use an electrically driven air condition system in addition to the electric steering assist. The combination of all this technology is expected to yield some outstanding fuel consumption numbers. Ford expects the Fusion hybrid to top the city mileage numbers of the Toyota Camry hybrid by at least 5 mpg. The 2009 Camry hybrid is rated at 33 mpg in the city so the Fusion should achieve 38 mpg.

The new Fusion and Milan will be officially unveiled at the Los Angeles Auto show on November 19-20 and will go in sale in the first quarter of 2009.