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Amazing Advances In Automobile Technology-Engine Developments
Awe-inspiring Developments in Motor Car Technology -- Engine Advances
{Overview:l}
Automobile engineering has developed to an impressive degree over the past decade and this third article of the set will highlght these advances. The way it was done will be spotlighted. This will show the development of engine technology.
In the 1990's one had the impression that there could not be any more advances in the technology in automobiles, development had reached its zenith. However ever rising pressure by governments, the looming scarcity of fuels and other clean air legislations have forced the engineers to develop more efficient motor cars and engines.
Manufacturers claims about their achievements with their products sounded almost too good to accept as true.
HOW WAS THIS ACHIEVED?
The huge advance in electonics made it possible. The outstanding development in electronics have contributed to this and really made it possible. Even the most infinitesmal operations of an engine in a modern automobile are controlled by present day computer power. Mechanical advances were just as impressive as the advances in electronics to bring automobile development to such a high standard.
Modern downsized engines with contemporary electronic controls have become highly efficient although their power output rivals and even exceeds that of engines in racing cars of bygone eras. You could think that these powerful engines would have a high fuel consumption, but that is not the case.
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When the mixture of air and gasoline in a cylinder is ignited, the burning gases expand due to the generated heat. This in turn puts pressure on the pistons and drives the crankshaft. The gases are ejected from the cylinder through the exhaust valve, when they have expanded, to make way for the new load of air being sucked in. The camshaft opens and closes the inlet and exhaust valves as and when needed.
In the past carburettors were the accepted way to mix petrol and air in the proper ratio to burn inside an engine, but for today's engines that is not good enough anymore and fuel injection has replaced the carburettor completely.
With sometimes only a single carburetor, the mixture could not be evenly distributed to every cylinder as the length of the inlet tract differed for each cylinder. Some cylinders received a lean mixture so the mixture had to be enriched to counterbalance for that resulting in a higher gasoline consumption and lower efficiency.
Nowadays you will not find an engine without fuel injection as it has become indispensable for the even distribution of the mixture to every cylinder. A computer controlled solenoid valve that is supplied fuel through a single pipe (common rail) at pressure, then injects the petrol into the engine. The gasoline is then injected into the inlet manifold.
Even this is no longer good enough. The clean exhaust and high efficiency demands on present day engines require the fuel to be injected directly into the combustion chambers under high pressure. To enable this lean mixture to burn, the squirt of the injectors is directed at the spark plug. The strata of rich combustible mixture that is needed to begin the burn, is called a stratified charge
Very high compression ratios and the pressures generated by turbo-charging also necessitated this development.
In the 1950's Mercedes Benz made a sports car, a 300SL, that had direct injection but from a mechanical pump. So things were done before.
High compression ratios.
High compression ratios (the ratio of compressing 10 parts of air into 1 part for instance), increase the efficiency of an engine. A ten to one ration as mentioned appears to be the norm nowadays. Certain factors however limit this.
When the pressures become too high certain undesireable things start to occur inside the engine, when the mixture starts to self-ignite, causing it to "ping". When the engine is under a heavy load and mostly at low revs, the engine at times emits a rattly pinging sound when using low octane fuel. This should be prevented as it can cause serious damage to the car's engine.
In the old days automobiles had side valve engines with large combustion chambers. A low compression ratio of 4 and even 5 to 1, was the common figure for these engines and was also necessary for the low octane ratings of the fuel available at the time. Compared to modern engines they were extremely inefficient, causing high fuel consumption.
Very high compression ratios, such as 11:1 and even 12:1 have become possible with modern petrol and the aforementioned controls. Only diesel engines used such high or higher compression ratios previously. With compression ratios reaching 20:1 diesel engines need these to operate, but that is another story and is going to be covered in another article.
In a follow up article the trend these days of downsizing engines and turbo-charging them, will be covered. Increasingly followed in Europe, this trend is less prevalent in America for various reasons but all this will be discussed there.
Author: Dieter Hoffmann a car, nut if ever there was one. My website is not about cars but about another of my interests i.e. woodworking. The name of the website is http://www.toolsforcarpentry.com where you can find information about woodworking tools plus plans for making just about any woodworking project as well as boats .
Is replacing piston rings in a 74' el camino 350 an easy job for someone with little to no expirience?
i have a 74 el camino, with a 350 v8, im looking to upgrade to a 750 cfm carb and manifold, and i fugure while i have the intake manifold off i might as well replace the piston rings, if not the pistons and bearings themselves.
I am not a mechanic but I know that you are talking about a major undertaking and that some special tools are required ! If you don't have the right tools you can over torque or under torque some assemblies . This sounds like a job for someone with more hands on experience .
civic EG9 first startup
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