2 Answers

diesel engines have a very high compression ratio compared to a gasoline one.for this reason, diesel engines make a knocking sound which it does make it harder to figure out when it has a piston rod knock or it is just a normal sound.

Fuel is injected into the cylinder and the air temp inside a cylinder may reach 1400 degrees F. The fine mist of fuel then ignites. the "clack" you are referring to is from the one burst of fuel igniting. not to mention that diesel fuel has many more BTU's than gasoline. The more BTU's the more energy contained in the fuel. A diesel engine today has a very high injection pressure of around 36,000 psi.

Diesel fuel has lost some of of it advantage in cost since the Environuts wanted to remove Sulfur from diesel fuel.   Now it costs more than premium gasoline but before the price was less than regular gasoline.

As in generally the case the Environuts are WRONG again.

One way to curb global warming is to purposely shoot sulfur into the atmosphere, true earth scientist suggest today.

The burning of fossil fuels releases carbon dioxide, a greenhouse gas, into the atmosphere. It also releases sulfur that cools the planet by reflecting solar radiation away from Earth.

Most researchers say Injecting sulfur into the second atmospheric layer closest to Earth would reflect MORE sunlight back to space and offset greenhouse gas warming, says Nobel laureate Paul Crutzen from the Max Planck Institute for Chemistry in Germany and the Scripps Institution of Oceanography, University of California at San Diego

The .Environuts are now proposing we take the sulfur our of Gasoline, further raising the cost around 25C a gallon

We need to get rid of the Environuts, running the Federal government, in November.