There has been a lot of talk about the ‘engine of the future’—where terms such as fuel cells, hydrogen and lithium ion dominate over displacement, cylinders and horsepower. It’s true that one day, these technologies will be found under the hood of most cars; as of the moment, the internal combustion engine still reigns supreme. In fact, it’s wrong to consider it a dead technology. With sophisticated new electronic and mechanical upgrades, the typical four-stroke engine is still the world’s most viable, cleanest and dependable technology. Spearheading the green movement are clean diesels and hybrids.
Diesel engine technology isn’t new—it’s over a century old. It uses a compression ignition cycle, where ultra-high compression ratios in the combustion chamber ignite the fuel/air mixture as opposed to using a spark plug in a gasoline-fed engine. The negative mindset towards diesel engine is mostly based on the diesels of yore: stinky, smoke-belching and slow. However, the advent of sophisticated high-pressure direct-injection systems and special exhaust emission systems has transformed them into a reliable and clean power plant.
The American car buying public, staunch opposed to the diesel engine, has begun to take notice. Companies such as Mercedes-Benz and Volkswagen are now introducing their clean diesel technology. Though gasoline-electric hybrids hog the headlines for their ability to sip unleaded in a very frugal matter, diesels can do just as well. In fact, some diesel engines have the ability to post better real-world fuel economy figures than that of hybrids, especially on the highway.
Unfortunately, diesels are more costly to produce than gasoline engines, so there’s a higher cost upfront when you’re purchasing a new car. The added cost varies per make and model, but sometimes they can be as high as P 100,000 more for a comparably equipped gasoline-powered car.
Another consideration is the high sulfur levels of Philippine-spec diesel fuels. A big factor in what makes these clean diesel technologies useable is its ultra-low sulfur levels. If the country were to shift to this ultra-low sulfur variety (the same one they have in Europe), huge investments will have to be made by refiners, and in turn, these will eventually be passed on to the consumers. And since diesel-powered trucks are used to deliver basic goods and services, the cost of goods will certainly go up and will start a chain reaction leading to the higher cost of living.
When oil almost breached the US$ 150 per barrel mark last year, hybrids have been thrust into the spotlight. Suddenly, hybrid car owners aren’t limited simply to the ecologically-minded and Hollywood celebrities anymore. Suddenly, everyone wants a hybrid—from soccer moms to yuppies. And car companies are obliging with the numerous choices available (at least in other markets). Toyota and Honda recently rolled out new versions of their Prius and Insight cars respectively, while Ford and even Hyundai and BMW are not too far behind.
Though there are different subcategories of hybrid engines out there, basically they all work on the same principle: using battery-powered electric motors, hybrid engines reduce the energy required from the vehicle’s gasoline or diesel engine. In turn, this save fuels. Complex electric brains regulate the moment the electric engine or the gasoline kicks to life or shuts down, making the entire process seamless and unobtrusive.
Most hybrids can operate on pure electric power for short distances at city speeds. This gives better urban or city fuel mileage figures as compared to highway driving (the direct opposite of diesel engines). For example, the new Toyota Prius is rated at 21.25 km/L in the city, but only 20.40 km/L on the highway. Clearly, hybrid cars benefit those who travel in low-speed urban settings rather than long provincial drives.
The downside of hybrid cars is their tendency to exhibit lazy acceleration compared to diesels. Some also exhibit odd driving behaviors, which irritate those switching from a traditional gasoline-engined car.
For example, the brakes on some hybrid cars feel unusual because a regenerative motor kicks in when you brake. The motor is used to recapture the vehicle’s kinetic energy to store as electricity on the on-board batteries. It’s good for boosting mileage, but the brake feel is akin to driving with engine braking even on flat surfaces. Hybrids also commonly use an electric power steering system. These have the tendency to have a less direct feeling that’s closer to a video game than a sports car.
The driving dynamics aside, the complexity of hybrid engines also work against it. The special components, programming and integration systems make hybrids more costly to produce even compared to diesels.
Despite the popularity of diesels and hybrids, the traditional gasoline engine isn’t that far behind in terms of being ‘green’. In fact, with the continuous introduction of new technologies, they actually represent a solid economical choice at a low purchase cost. Technologies such as variable valve timing and improved engine control as well as the move towards transmissions with more forward gears all contribute to the increased efficiency of gasoline-fed engines. And this isn’t even counting those new types of fuel injection technology such as direct gasoline injection which are now slowly becoming mainstream.
Moving a step further into the future, Mercedes-Benz is developing what it promises to be the ‘best of both worlds’—a gasoline engine with the efficiency of a diesel: the DIESOTTO engine. It uses a highly efficient combustion process similar to a diesel engine. In conjunction with other technologies such as direct fuel injection and turbo charging, it produces 238 horsepower and 400 Nm of torque from a four-cylinder engine with a displacement measuring just 1.8-liters. And the promised fuel economy? Around 18.86 km/L.
Engine technologies such the DIESOTTO are still way off into the future, perhaps as late as beyond 2014. Right here and how though, it’s good to know that the internal combustion engine, a proven technology over a century old, is still continuously refined. Though things such as fuel cells and hydrogen-powered cars help focus the driving public’s attention towards ‘driving green’, the tried-and-tested internal combustion engine, be it the traditional gasoline engine or clean diesels or hybrids will still continue to power cars. And they’re no less environmentally friendly. The internal combustion isn’t dead…it just got better.
By Ulysses Ang
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