The new 16-valve I-4 engine can displace from 1.8 liters up to 2.3 liters using different bore and stroke combinations with potential for up to 100 different derivatives. As a measure of its global significance, the new I-4 engine will be built in four plants on three continents.
“Eventually we expect to build up to 1.5 million of the new I-4 engines annually, which will represent about 20 percent of our total engine production,” said Dave Szczupak, vice president of Powertrain Operations, Ford Motor Company. “These I-4 engines eventually will replace up to eight different Ford and Mazda families of four-cylinder engines globally.
“The new I-4 engine family gives us unmatched flexibility to meet and exceed consumer expectations across a broad range of products,” added Szczupak. “From the same basic architecture, we can build a quick-revving engine for sporty performance, or a larger-displacement version with enhanced torque suitable for our popular Ranger compact pickup – and we can do both in the same engine plant. This offers us tremendous efficiencies.”
Global development, production
Design and production of the new family of I-4 engines has been a truly global effort. Mazda engineers in Japan led the design of the new I-4, and a team of Ford experts from North America and Europe led the vehicle application engineering and development of manufacturing plans.
As an example of the new engine’s flexibility, a variety of Ford and Mazda brand vehicles currently offer or will offer the new engine in both “east-west” and “north-south” configurations for front- and rear-drive applications, including:
- The Ford Mondeo in Europe with 1.8- and 2.0-liter versions, built at Ford’s Chihuahua Engine Plant in Mexico.
- The Ford Ranger pickup with a 135-horsepower 2.3-liter variant built at the Dearborn (Mich.) Engine Plant in the United States.
- The restyled Mazda MPV minivan – introduced in April and built at Mazda’s Hiroshima plant – was the first Mazda vehicle with the new engine.
- The all-new Mazda6 midsize sedan, sold in North America, Europe and Asia (as Atenza), offers three displacements: 1.8-liter, 2.0-liter and an advanced 2.3-liter with Mazda's Sequential Valve Timing (S-VT), which improves performance efficiency.
- Many more products set to be introduced around the world over the next few years, such as Ford Escape hybrid-electric vehicle (HEV), to debut in late 2003.
The first engines were produced in Chihuahua, Mexico in the third quarter of 2000. The Dearborn Engine Plant began production of the 2.3-liter I-4 in the second quarter of 2001. Mazda’s Hiroshima, Japan plant launched I-4 production in January 2002. Valencia, Spain launches later this year for various European Ford applications.
“It was truly a global engine development program much like the Ford Focus was a global vehicle development program just a couple of years ago,” said Dan Kapp, chief engineer of Powertrain Operations. “We used the design expertise of the team in Hiroshima, the manufacturing expertise of the team in the U.S. and Europe, and the vehicle application expertise of the teams in Europe and the U.S. As we develop each new vehicle, a dedicated team of engineers from the vehicle program tailors the I-4 to suit the vehicle’s requirements.”
Engine specifics
The new I-4 engine family is designed to provide dependable performance and high levels of driving quality throughout its service life. The objective for the I-4 engineering team was to give customers more of what they want – performance, drivability and smoothness – with reduced fuel costs, lower emissions and minimal maintenance requirements. As an example, the engineering team specified a 10-year, 150,000-mile minimum life for major components. Many engine systems require no attention during this span, other than regular fluid and filter changes.
The new I-4 engine family makes extensive use of lightweight aluminum components, which offer both a weight savings – approximately 40 pounds compared with the equivalent Zetec I-4 engine – and chassis dynamics benefits, such as improved weight distribution front-to-rear, and higher power-to-weight ratio.
This is part of a continuing trend within Ford and the automotive industry toward aluminum over cast iron for engine blocks and cylinder heads. Ten years ago, the typical vehicle had 190 pounds of aluminum. Today, aluminum comprises more than 275 pounds of total vehicle weight, according to The Aluminum Association, Inc. With a total annual volume now of more than a million units, Ford builds more aluminum engines than any other manufacturer in North America. With the new I-4 engine, that total will increase.
Cylinder Head and Valve Train
The cylinder head’s Dual Overhead Cam (DOHC) design uses Direct Acting Mechanical Bucket (DAMB) tappets and an aluminum alloy (AA319) “high flow” cylinder head with press fit valve seats, which helps to improve long-term sealing.
Valves and tappets are individually graded for consistency. This assures their ability to maintain proper valve clearances over the engine’s entire life, without the use of shims. Lobes on the chain-driven cast-iron double overhead camshafts are chilled during manufacture to harden them. These actions help to eliminate valve adjustments throughout a service life of 150,000 miles or 10 years in use. Each cam runs in five cam bearings, for smooth and quiet operation.
Intake valves are 35 millimeters, with 30-millimeter exhaust valves. They are mounted at an included angle of 29 degrees to each other in an asymmetric arrangement – the intake valves are 19 degrees from vertical and the exhaust valves are 10 degrees from vertical. This allows the spark plugs to be mounted near the center of the “pentroof” style combustion chamber, promoting circular flame propagation and improved fuel economy, especially under partial load.
The camshafts run directly in the aluminum cylinder head and are driven by a “silent” chain, which provides quieter operation. A spring arm maintains proper tension, and a hydraulically activated composite damper controls chain movement. The camshaft cover is made of cast aluminum alloy to contain valve train noise and assure warp-free sealing for life.
Along with durability and silent running, engineers worked to make engine components as fuel-efficient and lightweight as possible. A good example of this is the new, highly durable piston, ring and connecting rod assembly, which provides about 15 percent weight advantage vs. other modern engines, thus resulting in lower overall weight, superior NVH, lower friction (or parasitic losses) and a free-revving engine characteristic.
Power and Performance
The new I-4 engine family offers product development engineers a great deal of flexibility in achieving the best balance of fuel economy and power output for each application. For example, in a small car application, the engine is calibrated to deliver excellent fuel economy with torque biased toward the lower speeds where most small-car owners drive.
For enhanced efficiency, the electronic thermostat control uses a wax capsule that melts at a specific rate to signal the thermostat to open and close. It begins to open at a relatively high temperature of 98 degrees Celsius to support improved fuel economy through reduced friction, while allowing PCM-controlled actuation during high-load conditions.
For further fuel efficiency, the engine uses 5W20 SAE (ILSAC GF-3) grade oil for reduced resistance to flow, and operates at a relatively low idle speed of 700 rpm. Maximum engine speed is 7,000 rpm.
Engine Noise, Vibration and Harshness
The ratio of the connecting rod length to crank throw (known as L/R) governs the magnitude of second order harmonics generated by the reciprocating masses. These second order shaking forces in the new I-4 engine are approximately 15 percent less than for the equivalent Zetec unit, for improved smoothness.
A host of low-noise features enhance engine refinement. These include a single, service-free poly-V accessory-drive belt made of composite rubber, an automatic belt-tensioner, an alternator with low-noise, dual internal cooling fans and a fully length-symmetrical intake manifold.
The deep-skirted, closed-deck sand casting of the block features cast-in-place, cast-iron bore liners with tightly controlled geometry. A die-cast aluminum bearing beam and cast structural aluminum oil pan provide a strong and stable bottom end.
Engine assembly contributes to quiet operation, as components are select-fit to more exacting tolerances. In an example of attention to detail during construction, all 10 bolts that secure the lower bearing beam are tightened simultaneously, to assure even torque over the entire structure every time. This assures that the bearing beam isn’t warped during assembly.
Electronic distributorless coil-on-plug ignition includes an optimized cylinder knock-control system that continuously adapts the engine’s operating parameters in real time to optimize performance and economy.
Crankshaft and Pistons
The shell-molded, cast-iron crankshaft features five main bearings, four pin journals and eight counterweights for smoothness. The corners of each bearing and crankpin journal are rounded, to reduce stress points.
The lightweight alloy pistons feature a low-friction coating. The connecting rods are fracture-split sintered steel for precise fit when reassembled.
New intake manifold
The computer-designed intake manifold is a prime example of the attention to detail that went into engineering the new engine. It is fully symmetrical, lightweight and made of friction-welded plastic to reduce flow friction and stay cooler than cast metal. This design allowed engineers to “sculpt” the sound of the 16-valve engines to be sporty yet refined.
Within each of the intake manifold’s four runners is a butterfly valve that restricts the air passage at low speed. This improves low-speed efficiency through inducing a “tumble” or turbulence by accelerating the air/fuel mixture into the combustion chambers. At higher speeds, the butterfly valves open fully, to meet the engine’s requirement for air flow. At these higher flow rates, the port shape itself ensures proper “tumble” of the air/fuel mixture for best combustion.
The intake system also features a new, solid-state temperature and pressure sensor, which makes more precise air mass measurements. These are constantly relayed to the electronic engine management module for efficient engine operation.
Fuel Injection System and Emissions
A new four-hole fuel injector design delivers a highly atomized-spray pattern directly toward the twin inlet ports of each cylinder, for more spray penetration, better atomization and less cylinder wall wetting than a single-hole injector. This in turn translates into good drivability and low emissions. Sequential electronic fuel injection (SEFI) control injects precisely measured quantities of fuel into each cylinder individually, at the optimum point in each combustion cycle.
All of the new I-4 engines have been designed to meet European Stage 3 emissions rules and U.S. Ultra Low Emissions Vehicle (ULEV) standards, with capability to meet and exceed Stage 4 requirements. Specific emissions actions include close placement of the catalytic converters to the exhaust manifold to allow them to reach operating temperatures more quickly, and electrically controlled exhaust gas recirculation that recycles inert gas into the combustion chamber to reduce NOx emissions and improve fuel economy.
5/28/02