Petrol Engines as Powerful as Diesel Engines?

Petrol engines are already inherantly more powerful than diesel engines by comparison of displacement. (a 1.6L petrol engine typically produces more horsepower than a 1.6L diesel engine)

I am going to assume that you are talking about torque and not horsepower. The reason diesel engines have much higher torque than petrol engines is because they have a longer stroke to be able to have the needed much higher compression.

The reason why diesels have less horsepower is because they have a longer stroke, which limits their ability to achieve higher RPMs. (Higher RPMs produce more horsepower as long as the torque value does not drop).

So back to your question, how can a petrol engine produce more TORQUE than a diesel. Two ways: 1. Increase the displacement of the engine. (more cylinders, larger cylinders). 2. Forced induction (Turbocharger, Supercharger, Nitrous Oxide).

Greetings,

Diesel fuel has more heat value per pound than gasoline. Driving a 100 hp pump with a diesel engine will take a smaller volume of fuel that would a gasoline engine. To ask a gasoline engine to produce sustained high torque like a diesel engine will require a redesign of the typical gasoline engine. Typicaly deisel engines are rated at 3000 rpm and less dependeing on piston velocity limits. Gasoline engines generally are 4500 to 14000 rpm depending on a variety of factors.

Waukeshau makes natural gas industrial high torque engines that compete well in a typical diesel application.

The onlt way to make a typical gasoline engine match the torque curve of a diesel engine is through the efforts of a compressor that will cram more air into the cylinder.

But do that with some praying about the strenght of the components you are stressing to several times thier design consideration.

In the end, it has as much to do with economics and perception as engineering.

In automobiles, typical gasoline engines produce more horsepower than diesels, given comparable applications. Diesels are more fuel efficient. Compare specs for a diesel Jetta, versus the gasoline equivalent. The turbo diesel in the Jetta comes close to producing comparable horsepower, and provides much better fuel efficiency, but in the US, people strongly prefer the gasoline engine version. People here don't like the smell of diesel fuel, and don't like the truck-like perception of the diesel engine. If we really cared about fuel efficiency, we'd all be driving Jettas (and Priuses) rather than Ford pickup trucks.

In the US, large pickup trucks with diesel engines carry a large cost premium, but sell fairly well. In pickup trucks, truck-like perception is no longer a disadvantage, but instead an advantage for a certain type of buyer.

Getting still larger, virtually all over-the-road trucks are diesel, because the economics are much better: better fuel efficiency, lower maintenance costs, greater durability. The truck owner can say to the driver "I don't care if you don't like the noise, or the smell, I care only about efficiency." The same goes for ships, trains, etc.

If you drive a Mercedes or VW diesel, you can hardly fail to be impressed with the overall drivability. But in the US, they sell in such tiny numbers as to be almost invisible. In Europe, diesel cars are very popular. The market perception is different (and more sensible, in my view).

In markets in which the absolute highest horsepower for a given weight is the priority (fast motorcycles, for example) gasoline engines rule. In this market, outputs of 140 hp per liter and up are typical. (This is about twice the HP per liter of a typical car.)

Another market: small airplanes. Here, a diesel would seem ideal because of the low operating rpm. (A large, slow-turning prop is more efficient than a smaller faster-turning one.) However, most airplane engines are very low in terms of HP per liter (30 HP per liter is typical), but quite good in terms of HP per pound (and great in terms of reliability). Diesels are almost never seen in this market because of the high weight that comes about from dealing with very high peak combustion pressures.

I know of an idea in my head that has been there for a long time now that I think should make a petrol engine have more horspower as a diessel engine of same capacity in terms of fuel consumption, cylinder size, etc. The idea is about making the petrol engine of a longer stroke and still being able to operate without spontaneuos ignition due to the high compression. Esan, O. K. (Engr.), Nigeria

Why do you have this need to make a pertol engine as powerful as a diesel engine? Irrigation, stand alone electrical generator, etc. Are you concerned with the cost of the diesel? If that is the case, the diesel is more costly because of it's design principle. Very high compression to create the heat source necessary to ignite the injected fuel. A petrol engine has a much lower compression and a spark plug to ignite the petrol. So diesel component parts are heavier and machined on average to closer tolerances to withstand the higher stress loads.

You will have to do a cost analysis to determine what engine type is best for your needs as it relates to service use and time. Vendor access, service and parts avalibility need to be considered also.

I know of an idea in my head that has been there for a long time now that I think should make a petrol engine have more horspower as a diessel engine of same capacity in terms of fuel consumption, cylinder size, etc. The idea is about making the petrol engine of a longer stroke and still being able to operate without spontaneuos ignition due to the high compression. Esan, O. K. (Engr.), Nigeria

Diesel fuel is more crude than petrol (gasoline) and the impurities often freeze up here in Canada. Therefore a lot of the biodeisel and cheap deisel oils give you trouble, and trouble can be more than a nuisance, it can be fatal. Us Canadians shy away from deisels for this reason. The problem is not as bad as it used to be, but then, the oil is now much higher grade, and therefore more expensive.

I know of an idea in my head that has been there for a long time now that I think should make a petrol engine have more horspower as a diessel engine of same capacity in terms of fuel consumption, cylinder size, etc. The idea is about making the petrol engine of a longer stroke and still being able to operate without spontaneuos ignition due to the high compression. Esan, O. K. (Engr.), Nigeria

I don't think you have a complete understanding of a petrol engine vs. the diesel engine. The design principles are as different as apples and oranges. Please refer to your local library or a web search to help you understand the differences.

Regarding your idea to increase the stroke of the petrol engine, that is viable given you have enough clearance of the engine block and the connecting rod. The machining necessary to modify the crankshaft is called 'offset grinding'. This type of machining would reduce the diameter of the rod throws, it moves the center of the throw further out to acheive the increase. It would be better if you could purchase a crankshaft from the manufacture. Make sure the new crankshaft has the same cylinder bore spacing as your current crankshaft.

With all this, you also need to increase the cylinder compression ratio(CR). This will provide the driving force to take further advantage of the increased stroke. However, increasing the CR means more stress on the head and engine block. Also with your fluid power source being petrol, the CR increase must be limited to only a few points of an increase otherwise you will expierence pre-ignition. That condition will possibly blow the head off the block.

Conclusion...you cannot make an apple into an orange. You might have better luck with the petrol engine but it will be expensive, you will need the help of an excellent mechanic, and he might just shake his head and walk away. With all the time, trouble and money it will take...buy the diesel or find an appropriate use of the petrol engine.

Cheaper to buy a diesel or engine to fit your requirements then to modify something to fit your needs in terms of time or money. If you are looking at improving current technology, the main problem you face is detonation from too much compression. Increase the compression valve timeing would have to be changed in order to optimize your output. Tighter tolerances would aslo help. Better and lighter materials to hold up to the higher forces in the cylinders and on the pistons due to higher velocities. Big $$$$$, beter to buy.

To simply say it. Deisel is as slow to burn and hang onto energy as engineers are to encapsulate the fuel combustion and return useful power. I hope I am not being a wise ass.

Gas burns too quick.