Under the Hood

Powertrain

The powertrain is one of a car’s most complicated parts. The term “powertrain” refers to a system of bearings, shafts, and gears. Together, they send the engine’s power to the axle. Plastics can help reduce the number of parts needed per component.

Plastics are well suited for use in the powertrain because they can reduce costs and weight and dampen noise and vibrations. We even use plastics to make engine mounting clevis bracket. Air intake manifolds, cam covers, crankshaft covers, fuel system and engine cooling shutters are just a few examples and, this is only the beginning.

The 2016 Alfa Romeo Guilia features an innovative composite engine coolant control valve. This product design allows good fluid control and low coolant leakage at the seals on the valve moving components. Dimensional control is provided through innovative molding and assembly processes with the combination of PPA and PPS materials. The component results in an approximate 2% increase in fuel efficiency saving consumers money at the pump.

Using 50% glass reinforced polyamide plastic for engine brackets enabled improved NVH in the powertrain of the Mercedes 2017 E-Class Coupe. An innovative injection molding tooling concept was developed for production resulting in significant cost savings.

Drive Shaft

A driveshaft transfers power from the transmission to the rear axle of the vehicle. If a steel driveshaft fails, it can project shrapnel in all directions. It can dig into the ground, catapulting the vehicle into the air. Plastic composite driveshafts use carbon and polymer fiber.

Upon failure, composites tend to burst into small fibers or “broom,” posing less danger. In one vehicle, it took almost 20 times normal operating torque before failing. Composite driveshafts can be up to 50% lighter. This means less energy to spin the shaft and more energy to spin the wheels.

A composite shaft can have greater torsional flexibility.  This translates to a higher angle of rotation per torque load than traditional shafts. Increased torsional flexibility helps absorb impact loading (torque spikes) such as “clutch pop.” This increases the life of other drivetrain components connected to the shaft.

Engine Components

Material engineers build resins by the molecule to meet the heat demands of today’s engines. They have revolutionized engine part design.

Valve covers reduce weight. Air-intake manifolds increase and smooth airflow. This lets an engine “breathe” faster. Plastic manifolds designers can build intercoolers right into the part. Intercoolers reduce the temperature of air from the compressor and exhaust. So the engine gets the right amount at the right temperature. Plus, the engine responds quicker during acceleration.

Integrated plastic parts like these increase available engine bay space. It leaves room for front-end pedestrian protection designs and re-burning exhaust gases gives us another chance to burn uncombusted fuel. A cleaner burn can decrease NOx and CO2 emissions.

Consider the heat inside the timing chain housing sealed against the engine. Low friction chain tensioners can reduce camshaft rotational torque. This increases efficiency on every crankshaft turn, by .04 percent. That adds up.

All 2017 F-150 trucks and Mustangs use these plastic tensioners and estimates this reduced gas consumption is equivalent to 12,000 barrels of oil.

The 2015 Hyundai Genesis uses an innovative all-plastic engine-room partition wall providing excellent sound insulation between engine and passenger compartments thanks to the use of composites.  Replacing stamped steel the injection-molded plastic partition has been found to reduce engine noise, lower part count and assembly time, and offer a 20% weight reduction without increasing costs.