Trends in passenger car motor oils: Evolving engine technology driving change
Think about how much vehicles have changed in the past few years. What may come to mind are all the new electronics, smart sensors, assisted driving features and more, but what’s less noticeable are the significant changes taking place under the hood.
Engine technology is evolving rapidly in response to three factors:
- Legislated and social pressure to reduce carbon emissions
- Consumers’ desire for lower fuel consumption which leads to cost savings
- Demand for more engine power while still fulfilling numbers one and two.
By 2025, U.S. federal mandates call for a Corporate Average Fuel Efficiency (CAFE) of 54.5 miles per gallon. That doesn’t mean every car has to meet that standard, but that every manufacturer must meet that as an average across their entire fleet, which may span a range of vehicles from large SUVs and pickups to small hybrids and electric cars. (For comparison, the average today is 35.5 mpg.)
The necessity to achieve greater fuel economy has driven new engine technologies. Three technology trends in particular stand out:
- Gasoline Direct Injection (GDI) – involves the high-pressure injection of fuel directly into cylinder combustion chambers rather than through intake valves. GDI is increasing in popularity and is expected to dominate the market within a few years. By 2021, GDI-equipped light vehicles are projected to account for 71% of the production market in North America.
- Turbochargers – used to be found exclusively in racing and high-performance sports cars, essentially they recycle hot exhaust gasses to increase power. They are increasingly commonplace, appearing in 21% of new vehicles as of 2015 and are expected to be in 80% of new cars by 2025.
- Downsizing – some engines are going down as small as one liter (which is small enough to fit in a suitcase) in efforts to reduce mass and weight to improve fuel efficiency. What’s important though, is that these engines don’t sacrifice power. New six-cylinder engines are the horsepower equivalent of yesterday’s eight-cylinder and the modern four-cylinder provide the power of what once took six.
As with all new technology, there are often hiccups discovered along the way as the technology matures; this is true of evolving engines. In the course of trying to develop more fuel-efficient engines without compromising power, manufacturers encountered something called LSPI (low-speed pre-ignition) – this is unwanted and uncontrolled pre-ignition in the combustion that can severely damage an engine over time. It is resulting in many warranty claims, and as you can imagine, a huge issue that OEMs globally have acknowledged and are working on alongside the American Petroleum Institute and major lubricant producers including Chevron. LSPI is largely a result of combining the major engine advancements into one package. This combination of technologies stresses the engine to a higher degree and leads to a need for improved motor oil to provide greater protection.
The smaller, GDI and turbocharged engines run hotter, experience more stress and have a higher power density; meaning the oil has to work a lot harder to protect the parts. That is why we have been seeing major development in the types of oils that are required for newer engines. OEMs have been moving towards ever thinner viscosities because they produce less fluid friction or resistance and therefore deliver better fuel economy. Though a 5W-30 weight oil may be the most popular now, that is changing and in a big way. The industry is forecasting the 0W viscosity grades (now several % of total North America PCMO demand) to constitute approximately 35% of total North America demand by 2025.
In a future entry we will take a deeper dive into full synthetic motor oil.