The Diesel Engine for Everyman Finally Comes into Its Own

Diesel engines have been in existence for over a century. They were invented for deployment primarily in industrial environments and in large-scale commercial transportation and shipping. The diesel engine is a high-efficiency engine design. With over a century's proven reliability on the record, it still does not enjoy mass market penetration the way the gasoline engine does. The diesel engine operates, predictably, on the energy derived from the burning of diesel, the heavy petroleum derivative. An engine built on the diesel system diverges from the traditional gasoline engine design in important ways. The defining characteristic of a diesel engine is that it achieves fuel-ignition not by means of a spark but by means of merely subjecting the fuel-air mixture to high pressure. While gasoline could ignite under pressure too, the critical pressure for gasoline is too low to be of use. Diesel has a sufficiently high compression requirement to lend itself well to a compression engine design. Diesel engine design uses some distinctive design features to function with these requirements.

To begin with, very high pressure is generated only by the use of a piston design that employs a long stroke; long piston travel necessitates the use of a slower cycle. Diesel also requires a fraction more time to respond to high pressure and ignite in a cycle than does gasoline to ignite to a spark, and the slow cycle speed becomes a design fixture. Diesel engines therefore turn at lower RPMs. In order that sufficient power be generated at low RPMs, diesel engines use larger combustion chambers. The combination of large combustion chambers, a long stroke travel and the fact that diesel holds more energy per unit volume than gasoline, make it possible for diesel engines to produce massive quantities of torque at low speeds: this is a recognizable feature that these engines are coveted for.

These qualities have some benefits that arise as a consequence. Lower engine revolution speed makes the diesel engine less prone to engine wear. Diesel engines have to be more substantially built than gasoline engines to withstand the higher pressures within. Diesel engines therefore benefit from a far longer lifespan than comparable gasoline engines. Diesel is a more viscous and heavy oil and the lubrication of exposed parts is better taken care of. All parts in contact with the fuel enjoy better reliability. The absence of the need for a spark prolongs engine life as well.

Since diesel engines offer high torque at low engine speeds, the handling of high-load vehicles becomes easier on the driver. Vehicle design involving smoother load handling becomes easier. Diesel engines also put out exhaust that is less filled with the signature toxic gases present in gasoline, such as carbon monoxide. The main pollutant out of a diesel smokestack is carbon soot. But proper engine tuning and maintenance can often bring this down to a minimum. Why is it then that diesel engines have not caught on with the general public the way gasoline engines have? A significant reason for this could be the fact that diesel engines are more difficult to tame physical rattle and vibration in. Also, while they offer massive power, their slow speed makes it difficult to offer sporty acceleration in a vehicle. Recent diesel engine designs have won significant new converts over from the gasoline engine. These new generation engines are every bit as refined, gentle and sporty as gasoline engines are expected to be. Only time will tell, but it certainly appears as if diesel engines have now come into their own.