#5449 10/27/95 Message from R. Scott V. Paterson Subject: Press: Ecopower ================== SAAB ECOPOWER: ADVANCED ENGINE TECHNOLOGY FOR TODAY'S AND TOMORROW'S SAABS Turbocharging Drives 1996 Saab Ecopower Concept NORCROSS, Ga. -- Turbocharging is second to none as an innovative problem- solver. For almost 20 years, Saab has used turbocharging to boost engine power, cut fuel consumption and reduce exhaust emissions. While some naturally aspirated engines use elaborate and expensive induction systems that rely on vacuum to.suck air into the cylinders, Saab has found that a greater volume of air can be pushed into an engine over a wider rpm range by a relatively simple exhaust-driven turbocharger. Saab revolutionized the concept of turbocharging family cars by applying an adjustable-boost turbo to a small-displacement engine with the introduction of the 1978 Saab 99 Turbo, followed by the new Saab 900 Turbo a year later. The Swedish automaker continues to be a leader in the production of advanced turbo engines, available on both the Saab 900 and 9000 lines. For 1996, Saab's turbo engines and their exclusive technology are collectively known as Ecopower. Not just a catch-phrase for a few engine features, Ecopower is the Saab development concept for current and future Saab engines -- a way of thinking in terms of maintaining world-class status in sensible performance, environmental responsibility and a high standard of comfort and driveability. The most obvious advantage of a Saab turbocharged engine is increased power. Normally, 30 percent of fuel consumed in an engine is emitted as exhaust, or unused energy. A turbo utilizes the exhaust gas energy and returns it into the engine for additional power. For every one horsepower taken from the exhaust by the turbo, four extra horsepower are produced at the engine crankshaft. Compared to a naturally aspirated engine of the same horsepower, a turbo engine is smaller, lighter in weight, uses 12 to 20 percent less fuel, produces more low- end torque and significantly lower exhaust emissions. The natural sound dampening qualities of the turbo itself allow Saab to use the same size muffler as on a non-turbo car, despite the higher power output. Simplicity and cost effectiveness are additional turbo advantages. For a naturally aspirated engine to match an Ecopower engine's high torque output and low emissions, it would require a combination of these add-on technological features at additional cost: variable intake manifold, tuned exhaust manifold, variable cam phasing, air injection at cold start and EGR (exhaust gas recirculation). Ecopower applies to Saab's full-boost turbos and Light Pressure Turbo (LPT) four-cylinder engines. The four Ecopower engines are the potent 1 85-hp 2.0L in the Saab 900 line, the award-winning 1 70-hp 2.3L LPT in the Saab 9000 CS, the 200-hp 2.3L in the Saab 9000 CSE and the impressive 225-hp 2.3L in the Saab 9000 Aero. EcoPower Technoloqy for Maximum Efficiencv The key elements of 1996 Ecopower technology are turbocharging with intercooler, Trionic engine management, dual overhead camshafts, four valves per cylinder, Direct Ignition (Dl), a pre-heated oxygen sensor and catalytic converter positioned close to the engine for quick warm-up. A catalytic converter does not become fully effective until it has been heated up to its full operating temperature of around 750 degrees Fahrenheit. For 1996, the catalytic converter has been moved closer to the engine, which has shortened the warm-up time by about 25 percent to less than two minutes, cutting emissions accordingly. Because a turbocharger absorbs excess heat, a catalytic converter can be moved closer to the engine without risk of overheating at high engine power. Also for 1996, the oxygen sensor is preheated to reach its minimum operating temperature of 375 degrees quickly, helping it monitor exhaust gases as effectively as possible, supplying information back to the Trionic system. Brain and Brawn: Saab Trionic Engine Management The award-winning Saab Trionic engine management system used for Saab Ecopower engines was designed and tested by Saab's own engineers. Saab is one of the few car manufacturers in the world to develop its own electronic engine management system. The brain of Saab Trionic is a 32-bit microprocessor, capable of carrying out two million calculations per second. Programmed with ideal combustion conditions, the microprocessor simultaneously monitors and adjusts the ignition tirning, fuel injection rate and boost pressure. Control is adaptive, which means that the system adjusts all calibration points while taking into account variations in engine parameters, such as temperature, load and even engine wear. Trionic analyzes the combustion process by using the spark plugs to measure ionization in the cylinders. A weak electrical current is applied across the gap of each spark plug after every combustion stroke. The voltage flowing back to the control unit measures the combustion efficiency in each individual cylinder. The system continually adjusts the fuel quantity, the ignition timing or the boost pressure to ensure each cylinder's fuel-air ratio is as optimal as possible. The result is a reduction in fuel consumption and exhaust emissions. Individual ignition timing tailored to each cylinder is possible thanks to Saab's Direct Ignition (Dl) system, featuring one ignition coil per spark plug. Introduced on Saab cars in 1985, DI provides up to 40,000 volts at the moment of ignition. The Trionic systems on full-boost turbo engines have an integrated Automatic Performance Control (APC) function, which helps regulate turbo boost pressure correctly, regardless of fuel quality or octane. APC allows all of Saab's Ecopower engines to run on regular unleaded fuel. Premium fuel is recommended only for the Aero's 225-hp engine. Light Pressure Turbo Is Intelligent Alternative Saab's latest turbo innovation is the Light Pressure Turbo (LPT), introduced on the 1995 Saab 9000 CS. LPT widens the application of turbocharging by shifting the focus of turbos from pure performance to performance assist. Designed specifically to provide strong low-speed torque and a smooth power application, the LPT engine effectively emulates the driving characteristics of a larger-displacement naturally aspirated engine while maintaining low emissions and high fuel economy. Boost pressure is limited to 0.4 bar rather than the sporty full-boost power of 1.0 bar in other Saab turbo engines. Because the boost pressure is fixed at 0.4 bar, APC is not required to control boost pressure. A boost gauge is also unnecessary, and no turbo badging is applied to the Saab 9000 CS. Addressing the "Turbo Myths" As turbo engines developed over the years, the term "turbo lag" became synonymous with turbocharging. Indeed, early turbo engines required several seconds to build full charge pressure. In contrast, today's Saab turbos utilize a small, low-mass turbine that spools up almost instantly. Boost pressure builds quickly, providing maximum torque on demand -- at engine speeds as low as 1,800 rpm on the 2.3L engine in the Saab 9000 CSE and Aero, and 2,100 rpm on the Saab 900's 2.0L engine. The LPT engine is even more remarkabie in its ability to mask the fact that there is a turbo under the hood. Totally integrated into the engine's power curve, the LPT reduces any perception of "turbo lag" or "turbo kick" to nil. Instead, the driver simply enjoys strong, predictable power at all speeds. Reliability issues have also haunted turbochargers, but the advent of electronic boost control and water-cooled center housings in the mid 1 980s addressed these concerns nearly a decade ago. Today's Saab turbo is a fully integrated part of the engine, designed and proven to be maintenance free and dependable for the life of the car. Saab's own warranty analysis shows that a turbocharger is as reliable as other major engine components for as long as the car is on the road (at least 15 years, in Saab's case). Saab's commitment to turbocharging and Ecopower technology extends beyond today's engines. Engineers are developing new turbo applications for future Saab powerplants. Some concept designs will be seen on this year's auto show circuit. ================== EOF The Saab Network saab@network.mhs.compuserve.com
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