As part of General Motors’ strategy to continue to improve fuel economy and reduce vehicle emissions, GM is placing a major focus on improving the traditional internal combustion engine. Around the world, GM is developing and implementing various technologies to help make this happen. From Twinport technology in Europe, to flexible fuel vehicle technology in the U.S., GM is making strides in applying technologies to conserve fuel and create fewer emissions in the process.

Improvements to the traditional gasoline engine

In addition to new and future technologies like hybrid electric vehicles and hydrogen fuel cell vehicles, we are continuing to make improvements to the traditional gasoline engine. Some of the key powertrain technologies that GM is implementing include:

• Active Fuel Management (AFM) — This technology shuts off half of the vehicle’s cylinders when less power is needed, such as during steady cruising speed or deceleration. With an eight-cylinder engine, this allows for driving in a fuel saving, four-cylinder-mode and then switching seamlessly back to a robust-eight-cylinder-mode when needed to meet the demand for greater power. GM has also just introduced a 3.9-liter, six-cylinder engine with AFM that allows the vehicle to run on three cylinders part of the time. GM’s debut of the V6 application is on the 2007 Chevrolet Impala.
  
  For the 2006 model year, 10 GM vehicles were equipped with AFM, and for the 2007 model year, 14 models utilize the technology. By 2008, more than two million GM vehicles will be equipped with AFM.
• Engine Variable Valve Timing — This technology helps optimize engine air flow for maximum efficiency and power. By 2007, we will produce 2.5 million engines annually that utilize this fuel-saving technology.
• Six-Speed Transmissions — Fuel economy is enhanced with a six-speed transmission because smaller “steps” are used between gears, compared to a conventional four-speed automatic. This allows the transmission to quickly find the best gear for the vehicle speed and road conditions. By 2008, GM plans to offer one million vehicles annually that will be equipped with this technology. Currently, GM has nearly 40 global vehicle applications that are using the six-speed transmission.

In addition to engine technologies, GM is focused on aerodynamics. Every vehicle we produce undergoes rigorous mathematical analysis and physical testing in the world’s largest automotive aerodynamics wind tunnel and lab to optimize aerodynamic shape development, maximize cooling airflow, and minimize wind noise. All of this work helps improve the fuel efficiency of the vehicle. In fact, next to engine improvements, aerodynamics is the second largest contributor to fuel economy gains.

Other key technologies that help improve fuel economy include:

• Regulated voltage control (RVC) — GM’s patented RVC technology optimizes alternator load by reducing voltage when the battery reaches 80 percent state-of-charge. RVC extends battery and electrical component life.
• Electric cooling fans — These fans replace engine-driven fans. They require less horsepower and produce less noise.
• Variable displacement air conditioner compressor — Replaces a fixed displacement compressor, providing an increase in fuel economy with A/C on.
  
• Electric power steering — Reduces mechanical losses by eliminating the pump, hoses, and hydraulic fluids.

GM has made fuel economy a priority, and we are placing significant resources and effort into producing cars and trucks that offer leading fuel economy and performance. In fact, for the 2007 model year, GM is offering more vehicles (23 in all) that achieve 30 miles per gallon or better on the highway than any other automaker, according to EPA estimates. We are achieving these results by improving engine and transmission efficiencies, producing vehicles with better aerodynamics, and minimizing vehicle energy losses. And we’re doing all of this without compromising on value, performance, or utility.

In Europe, GM added a new 1.8-liter 140 hp gasoline engine to extend the Opel/Vauxhall engine offerings. The new engine provides:

• More power, reduced fuel consumption, enhanced refinement
• Continuously variable camshaft phasing and two-step intake manifold
• Intelligent lightweight design further enhances efficiency

The highly efficient four-cylinder unit is available in the new Opel/Vauxhall Zafira, Vectra, and Signum.

The all-new four-valve engine features numerous technology-highlights:

• Two continuously adjustable camshafts (DCVCP — Double Continuous Variable Cam Phasing) to optimize the charge cycle
• A two-step intake manifold with a rotary sleeve instead of flaps to minimize flow losses
• A highly efficient oil-water heat exchanger
• A map-controlled thermostat
• A deep drawn exhaust manifold with an integrated catalytic converter

Tests with the Opel/Vauxhall Vectra resulted in the Motor Vehicle Emissions Group (MVEG)-cycle fuel consumption of 7.3 liters per 100 kilometers — 0.3 liters or four percent less than the previous Vectra 1.8.

Mass reduction, achieved by lightweight design, also contributes to the high efficiency of the engine.

Another key technology to improve fuel economy is the increased application of turbo charging. Two examples are the sporty, top-of-the-range OPC version of the Meriva, powered by a newly-developed 180-hp 1.6-liter ECOTEC turbo engine and the 2.8l V6 ECOTEC turbo in the Vectra and Signum.