Where does the internal combustion engine go from here?Bojan Popic | February 22, 2021
With most automotive manufacturers increasing their market share in electric vehicles (EVs), it is certain that personal transportation, for the long term, is going down the battery-powered route. Besides being efficient and cheap to run, modern electric cars are also easy to use and offer superb performance.
That being said, traditional combustion engines will probably keep their role as a automotive powerplant for several upcoming decades. Most car manufacturers are still developing them at large scales, both gasoline and diesel fuel types. These improvements mean internal combustion engines (ICEs) have strong, if gradually declining, future.
Technological improvements and better fuel efficiency
To ensure the future of ICEs, manufacturers will have to make them even more fuel efficient. This is because improvements in gas mileage are the only way of dealing with increasing fuel prices and strict emission regulations. To do so, manufacturers are introducing different new technologies and upgrades with every new model.
Features like turbocharging and high-precision fuel injection are just some solutions that ensure better engine and driving characteristics. With higher power outputs and more favorable torque ranges, manufacturers can use smaller and lighter engines. Besides improved efficiency, these units offer considerable savings in both weight and size. Drivetrain losses that come from auxiliary systems, such as power steering or air-conditioning, also have a negative impact on fuel economy. Increasingly, optimization or redesign of these systems ensures there are no unnecessary loads that take away a part of engine power. Enhanced oils and lubricants will have the same effect, as they will lower the friction between moving components.
All cars with ICEs have a transmission, which can have a significant impact on fuel consumption. Not so long ago, manual transmissions or conventional automatics with torque converters were the only options, both of which had their downsides. However, modern automatic transmissions that use dual-clutch or continuous variable technology offer better performance and improve overall efficiency. This is thanks to inbuilt algorithms that ensure the engine runs at optimum conditions for the gearing.
However, implementations of these new technologies and assemblies comes with several potential drawbacks. An increased overall price of the vehicle is one of them, as all these extra parts come at a cost. Still, adding components and assemblies to the engine increases its complexity, which may affect both reliability and maintenance costs.
Range, power and infrastructure
EVs brought about concerns in range and charging time - if an all-night charge can only supply 100 miles of range, it is impractical for many trips.
These numbers are getting better with every new generation - the premium version of the Tesla Model S offers more than 350 miles in single charge - but electric cars still suffer from certain limitations in these fields. Average daily drivers may not be deterred, as long as their daily commutes include shorter trips only.
However, these questions of range complicate longer journeys. Either the driver spends ample extra time seeking charging stations along the route and then waiting for the car's battery to recharge, or they get to the destination faster in an alternative technology, such as combustion engine. Charging stations and recharge time are the current, major bottlenecks in the proliferation of EVs.
As opposed to EVs, conventional cars with ICEs still have a huge advantage in terms of power density. A much higher range and a convenient refilling procedure that is fast and widely available mean they are the preferred choice for many applications and use cases. Commercial traffic is often a time-is-money proposition, and charging challenges often outweigh the fuel economy and sustainability benefits. Vehicle owners in remote or rural areas will have more difficulty finding impromptu charging that those in urban areas, even more so in developing countries where combustion engines are plentiful, but the electricity supply is sparse or unreliable.
In addition, the majority of towing, industrial and heavy-duty vehicles may still rely on ICEs for years to come. The Tesla Cybertruck promises an electric drivetrain that can tow up to 14,000 lb, although it is likely a year or more away from first customer deliveries. Yet it remains to be seen if it is a practical solution for contractors, industrial needs or even weekend warriors. Further up the industrial power food chain, electric options for excavators, wheel loaders and dump trucks exist - but the impracticalities of charging infrastructure and power density remain. Many construction sites won't have electrical service in the early stages of erection. And few of those examples will last a full eight-hour workday.
name="_jfuerzp68zsq">Hybrid vehicles and their advantages
Sometimes a balanced combination of two seemingly opposing technologies may give better results than each of them would do on their own. Hybrid vehicles are an outstanding example of such symbiosis.
It is important to know that hybrid vehicles come in several variants, with each of them using a different setup. In full hybrids, an electric drivetrain is accompanied by an ICE that is either can directly power the wheels, or feed the battery with electrical energy, or both. Mild hybrids have an ICE and electric drivetrain that are always cooperating - there is no ability to toggle between power sources. All types of hybrids are eligible to use an energy recovery system (ERS), which use a recuperation process to capture the kinetic energy when braking or coasting and store it in batteries. This energy drives the electric motor on accelerations to give it an extra boost and improve fuel efficiency. Plug-in hybrids, in their various forms, have significantly larger batteries and still require plugging into the grid at intervals to fully recharge. They may feature a range extender, which is a a small ICE that never feeds the drivetrain directly; it feeds DC current to the battery. This is the same premise behind diesel-electric locomotives.
Most notably, hybrids merge many of the benefits of ICEs and EVs. They have a very small carbon footprint, but larger than that of EVs. The ICE provides additional range when say, stuck in a rush hour traffic jam. They are not as dependent on charging stations as full EVs. But hybrids are not perfect. Two propulsion systems means additional parts, weigh and cost. And battery management can be difficult and lifespans unpredictable.
Yet with all their upsides, hybrids will remain a popular option for a long time, which in turns ensures the future for internal combustion engines.
It will take some time - decades or longer - for EVs to totally phase out ICEs. New technologies and innovations make them increasingly efficient and ensures competitive, improving fuel economy. Besides that, cars with gasoline or diesel engines have a greater range and more reliable infrastructure. And in the hybrid variant, they ensure the best of both worlds by exploiting the strongpoints while minimizing corresponding downsides.
About the author
Bojan Popic is an automotive journalist from Croatia. He has 10 years of experience in hands-on automotive diagnosis, maintenance and repair. He earned a master's degree in mechanical engineering from the Faculty of Mechanical Engineering and Naval Architecture in Zagreb, Croatia.
The mass and volume fractions of the ICE can be greatly reduced in hybrid vehicles by averaging power output of the ICE over the entire transport cycle. For a super high-performance hybrid vehicle, the storage capacity for reasonable grading ability, extreme acceleration, and regeneration should not have to exceed the energy equivalent of about four accelerations to cruise velocity. For flat land efficiency the storage device should not have to capacitate more than about one equivalent acceleration to cruise. These relatively small storage requirements are well suited to the high-power densities of super capacitors, which because of their nature, can greatly increase regenerative efficiency.
An efficient hybrid would have a significantly lower carbon footprint than EVs charged with fossil fuel generated electricity.
A properly designed ICE-Electric hybrid vehicle could eliminate all mechanical coupling in the drive train by using the power shaft of the ICE as the alternator rotor when wheel-hub integrated motors are used to apply tractive effort. Such a design could integrate all wheel independent no slip technology where acceleration and regeneration would be limited only by road to wheel adhesion.