Heat Energy Conversion

because the equipment needed to do this would;

1.) add more weight to the vehicle

2.) need bigger engine/motor move this weight

3.) need to reinforce the frame to carry this weight

4.) .......

The best is to make what you have more efficient.

The same was said about chimneys or stacks. Though some of this heat is regenerated. But people would forget that you need a draft that is created by the heat.

There is the cascading effect that is over looked.

p911

exactly what 911 said, it would cost a fortune to use thermopile's to generate sufficient power to charge a battery and then theres the weight and complex wiring

early VW beetles use the exhaust to heat the inside, this is ok until you get a leak then you get gassed occupants.

Its been thought of and discarded as not worth doing.

Good feedback.

Anybody who mentions the Carnot cycle deserves a GA.

It's the engineers dream to use the waste from an engine and do something useful with it. The internal combustion engine grabs the "easy bit" at high temperature, converts it to rotary motion and throws the rest away. Doing something useful with the waste heat can be done, but at the expense of a heavy and expensive appartus such as a Stirling engine or Rankine cycle engine. I was recently looking at the results achieved by Sataima University, Japan. They fed the exhaust gases from a 3.5 kW gasoline engine into a custom designed Stirling engine but only managed to get 3% of the exhaust gas energy out of it. Pretty discouraging!

Seems to me that a turbocharger is about the only reasonably small, light and cheap way to extract some of the exhaust energy.

You can convert the heat energy into electrical energy using a thermopile. There is a company who make such devices. Hi-z. They can recover 1 kW of electrical energy from the exhaust of a heavy duty class 8 diesel truck. A quick search says that such a truck might develop 300 kW. So the recovery is about one third of one percent.

There is a long way to go.

There is a lot of energy wasted in both petrol and diesel.

the petrol engine is only about 24% the rest is lost as heat.

if some way could be developed to remove the heat that is currently lost in the cooling system and the heat lost to the exhaust it might be worthwhile.

there is a combined heat and power systems used in buildings that use the heat to heat water and building

http://www.google.co.uk/search?q=combined+heat+and+power+systems&sourceid=ie7&rls=com.microsoft:en-gb:IE-SearchBox&ie=&oe=&redir_esc=&ei=zGvoS8WYNI_40wTu7-TKBg

http://www.hi-z.com/

thermo pile

http://www.google.co.uk/search?q=thermopile+generator&sourceid=ie7&rls=com.microsoft:en-gb:IE-SearchBox&ie=&oe=&redir_esc=&ei=MWzoS7HYDYb20wSbueHOBg

http://www.wonderhowto.com/how-to-peltier-module-create-electricity-from-heat-220628/

http://www.google.co.uk/search?q=how+to+make+electricity+from+heat&sourceid=ie7&rls=com.microsoft:en-gb:IE-SearchBox&ie=&oe=&redir_esc=&ei=kGzoS9OhGKj00gTHwuXJBg

Investigate the air conditioner of Mahatma Ghandi's car and you'll find something usefull for that heat.

Also Einstein and his helper developed a fridge powered by a small burning pilot (kerosene I guess). I myself, saw one of these in my younger years, in a rancher's house, they used it to make flavoured icicles.

How efficient? about a cup of kerosene per day

Yahlasit

http://www.thenaturalhome.com/gasappliances.htm

>>I myself, saw one of these in my younger years, in a rancher's house, they used it to make flavoured icicles.<<

I myself, used one of those until 2 years ago, when I got solar power installed. There are millions of those fridges in use today, mostly running on gas and used for camping. But they doesn't prove anything about improving the efficiency of an automobile.

The truth is, it doesn't take much to run a fridge. My current conventional fridge runs on solar electricity and consumes about 0.8 kWhr/day. Yours is probably not much different.

My car, on the other hand uses vastly more energy than that. Around 0.75 kWhr/km. So I could run my fridge for a day on about the same amount of fuel it takes to propel my car for a little more than one kilometer. Less than a cup full of fuel in fact.

Rather than generating electricity, stick in a turbocharger and use the waste heat to drive a turbine that'll pressurize air before it enters the motor's cylinders. A much better way to recover energy and raise an engine's performance.

Cheers! DZ

can u explain me basically how an engine works? Is is a 4-stroke engine or a different one?

Engine performs work . The manner in which the engine performs its work is illustrated below. The crank of the bicycle and the crank in the engine work in similar fashion. When the rider pushes down on the pedal of the bicycle, A, the force exerted on the crank causes the sprocket to be turned. The turning or rotary force thus developed is called "torque." Torque then is that which produces or tends to produce rotation. The pressure developed in the cylinder, B, when the fuel charge is burned, results in force being delivered to the crank of the engine through the piston and connecting rod so that power is developed in the engine. This force or power causes the rotation of the crankshaft and the flywheel. If a weight, C, is attached to a rope, and the rope attached to the flywheel which is being turned by the power secured from the burning fuel, the weight will be lifted. The amount of force thus developed is termed "foot-pounds of torque." For instance, if the radius of the flywheel were 12 inches or one foot and the weight lifted were 200 pounds then the torque would be 200 foot-pounds. This ability taken in conjunction with the speed at which the rim of the flywheel is moving is the basis of calculation of horse power. What is horse power? One horse power is the ability to lift 150 pounds a distance of 220 feet in one minute. The total amount of work performed is 33,000 foot-pounds a minute. The same amount of work would be performed if the horse were to lift one pound 33,000 feet a minute, or if his work resulted in lifting 33,000 pounds one foot in one minute. Due to the fact that in the case of early mechanical devices use was made of the horse as a source of power, the practice of speaking in terms of horse power, with reference to engines, has long had acceptance in the engineering fraternity. In the days when horses were used for power, if one horse could not do the work required, additional horses were added to make available the amounts of power required. Likewise, in the case of early engines, if a single cylinder would not do the work, other cylinders were added. In automobile engines, when it is necessary to increase the amount of power, other pistons are added. Of course, the bore and stroke of the engine have much to do with the power developed. Horse power developed by the engine, is used to turn the flywheel and transmission gears, and finally is delivered through the rear axle to the rear wheels, the friction of which, in contact with the road, causes the car to be driven along the highway. It may be said that the horse power developed in the engine is used to do work in propelling the car. The manner in which the parts of automobile engines are designed and work together to develop power is explained in the following pages of this chapter. Engine capacity Gasoline engines are made in sizes varying from the fractional horse-power engines used about homes for the operation of small machines, such as the washing machine, cream separator, and the light power requirements, up to engines developing as much as 1,000 or 2,200 horse power for aircraft and marine uses. Most automobile engines fall between the lower power ranges, seldom developing over 200 horse power. The ability of an engine to do work is dependent upon the power or the horse power developed. This in turn is dependent upon the capacity of the engine. A single-cylinder engine, has a certain capacity. Four similar engines connected together, has four times the capacity for work. As a matter of fact, it would likely develop more than four times the power for the simple reason that the larger number of cylinders makes for a more continuous flow of power, or, let us say, a more even torque. The size of the engine is ordinarily spoken of as having to do with the bore of the cylinder and the stroke of the piston. The larger these two items, the greater the displacement of the engine and naturally the more fuel which will be drawn in and compressed to be burned, and, of course, the greater the power which will be developed. Just as it is readily understood that a team of horses will do more work than one horse, so the student of automotive mechanics understands that two cylinders of the same size will do more work than one, and further understands that a larger cylinder or a cylinder with a greater capacity will do more work than a single cylinder of smaller capacity. For this reason we have all engines rated by bore and stroke and the number of cylinders, and this in turn gives the total displacement of the engine and determines in no small Way the capacity of the engine to do real work. There are two methods of rating horse power of engines, one of these being an arbitrary method of getting the S.A.E. rating which has to do with the licensing requirements in all states and in fact in most countries. The other is the actual power developed which is measured as brake horse power. These features will be discussed at a later point. If the student will remember that the same kind of action as that illustrated at A and B, is occurring at all times in the engine, when it is being operated under its own power, he can appreciate just how the power passing from the engine into the transmission line may be used to turn the propeller shaft. This in turn will drive the axle shafts which are geared 5 to 1 with reference to the propeller shaft and turn the rear wheels to drive or propel the car forward in the case of forward speed, or in a reverse direction in the case of reverse speed. The student should now have an elementary understanding of just what is meant by power, torque, and work in relation to the automobile and thus be in a position to understand the need of knowing the theory on which the construction of the gasoline automobile is made. Engine and ignition time Only those parts which are essential to engine or ignition timing are shown. Engine timing is done from cylinder Number 1, considering the first throw of the crankshaft and the first rod and piston. The two cams, the two valve lifters, and the two valves belonging to this cylinder are considered for this work. The camshaft gear and the crankshaft gear likewise are essential. Other parts of the engine are nonessential and, for the sake of the study and actual engine-timing process, may be entirely ignored. In addition to the parts named above, other parts are necessary for ignition timing. These are the timer-distributor, the ignition drive shaft and gears, all spark plugs, spark-retard device, ammeter, ignition switch and the primary wiring, the distributor (part of the ignition head), and the high-tension wiring. These units have all been gathered in compact, yet visible form, in the instruction stand illustrated. The stand does not illustrate engine-building practice, but rather illustrates exact timing of parts, functions of parts, and interrelation of those parts essential to engine and ignition timing. Diesel engine principle Fuel is not drawn in with the air but is injected after the air charge has been compressed. Compression ignition is used to fire the mixture. Otherwise the cycle of operation is the same as for the gasoline engine. Since the earliest successes of the motor car, the tendency in cylinder design has been along the line of arranging them all in one block. The earliest designs called for single cylinder castings, mounted individually on a crankcase casting. Next came the cylinders cast in pairs for the four-cylinder engine, and with the development of the six-cylinder engine the cylinders were cast in two blocks, three to a block. Shortly, the manufacturers were casting the four cylinders in one block for the four-cylinder engine, but the practice of casting the six cylinders together was a bit slower in being made practical. Eight cylinders in V form or in line in a single block are designed and produced without eliciting any comment in modern practice. However, the matter of turning out perfect castings, as complicated as are the castings for a modern motor-car engine, is no slight feat. Not only are the water jackets and other passageways cast about the cylinders for their cooling, but the intake ports and exhaust ports are cored out in the casting. All manner of bosses, brackets, and other parts are cast as part of the single-block casting. A block so cast is without a multitude of joints and connections, which are needed when cylinders are cast separately and assembled on a crankcase. Perhaps the greatest improvement, however, is one of engine operation. Casting the cylinders in one block helps to maintain an even operating temperature throughout the entire block and assures approximately the same operating temperature to all cylinders. Power impulses The number of cylinders in an engine has less to do with the power of the engine than with its smoothness. For instance, it is easily possible to build a 100-horse-power engine with four, six, or eight cylinders. Naturally the pistons in the four would have approximately twice the head area of those in the eight. Each power impulse gained from burning fuel charges would need to be approximately twice as heavy for like engine speeds of an eight. Heavier impulses result in greater strains and consequently more vibration. While it is true that inherent balance and other engineering data enter into this picture, it is generally conceded that the forces of the power impulses are the largest factor in smooth or rough engines. Engine bearings In practically all instances, the main bearings of motor-car engines are cast or fitted into the webs and ends of the crankcase. These bearings are usually of the babbitt-lined type, in most cases. Ball bearings have been used with success, but this construction is seldom used for passenger-car engines. Lead-bronze, steel-backed bearings are claimed to show a longer life under conditions of hard service. Airplane and marine, as well as truck engines, are using them with complete success. They are also used with success in passenger-car engines. The babbitt and bronze bearings are what is termed the split-bushing or plain-bearing type. The upper halves of the bearings appear in the crankcase ends and webs, while the lower halves are bolted onto the upper halves by means of studs set into the crankcase metal. The larger bearing caps are provided with four stud holes. The backs of the bearings may be aluminium, cast iron, cast steel, malleable iron, or drop forgings. The babbitt metal, with which they are lined, may be sweated or spun into the cap, or the cap may be machined to accurate limits and the babbitt sweated onto a brass, bronze, or steel back. Shims are carried between the two halves of main bearings in many cases of splash-type lubrication but are not commonly used for bearings in forced-lubrication engines. They are thin sheet metal, stamped to the general form of the face of the cap where it joins onto the upper half. Cylinder heads With the success of the motor car and its adoption by the public came an insistent demand to have the heads made so that carbon could more readily be removed. This led to the rather universal practice of making cylinder heads in separate castings so that they might be removed. Manifolds The design of manifolds is of interest since the efficiency of the engine is largely dependent on them. For updraft carburetors the intake manifold is fitted with a flange at the centre bottom, and with flanges on the ends where it is attached to the cylinder block. The exhaust manifold, has been designed to bolt onto the cylinder block, in a manner which connects the upper part with each exhaust-valve port of the eight-cylinder engine. The heater at the centre permits exhaust gases to surround the intake manifold and warm the incoming fuel charge. These manifolds carry three exhaust-port flanges which are connected to the cylinder block. Heat flows from the exhaust passages into the metal of the manifold. Fuel charges, passing through the intake passageways, pick up this heat. Oil pans and oil sumps The lower half of the crankcase is made from pressed sheet metal in practically all cases. This makes it light and, at the same time, strong. It will stand the occasional jar or blow better than if it were of cast metal. Being in the lowest position of the parts making up the power plant, it not infrequently is struck by flying stones or receives a blow from some other cause, especially in the out-of-way places and in rough going. Flywheels The design and construction of flywheels, on first glance, would seem to be of slight interest. As a matter of fact, much of the stamina of the engine, as well as its flexibility and pickup, is dependent on the flywheel. In the first place, it is essential to the smooth operation of the engine. It stores up the energy received from the explosions within the cylinder, and gives it off at those points where the engine develops no power, otherwise the engine would not run. The first explosion would drive it to bottom dead centre, and without the flywheel to carry it on, it would stop there. High-speed racing engines use very light flywheels. This duty of keeping the engine turning at one time was of greater importance than in later design. Much more weight is generally carried in the crankshaft than formerly, and where counterbalances are used, they serve to store and give off the required energy. Some manufacturers use two flywheels, one on each end of the crankshaft. This has the effect of placing the entire job in more even balance — similar to the result obtained by the use of counterbalances. The flywheel serves the purpose of acting as a mounting for the starter ring gear. Sometimes the teeth are cut directly in the flywheel metal, and again the wheel is machined to receive a toothed ring. In the latter case, the ring only is replaced in case of damaged teeth. Vibration dampers The tendency of a rubber band, which has been wound up by twisting, to unwind as soon as released, as in the case of a toy airplane, is well known. If a yardstick is grasped with one hand on each end it is possible to twist or wind it. As soon as pressure is released it snaps back. So it is with a crankshaft. The force tending to wind it is delivered from the piston through the connecting rod on each explosion. Unless a damper is provided it snaps back to position so rapidly as to set up engine vibrations. Dampers may be placed on the forward end of the shaft outside the crankcase or on one of the forward throws of the shaft within the engine case. They operate on the principle of gradual release of the power stored on the wind-up, allowing the shaft to unwind slowly. Try this with the yardstick, first winding it sharply and then releasing suddenly, and then, on the second trial, hold both ends and release gradually. The higher the engine speed the greater the tension to hold against severe vibration, and the lower the engine speed the less friction required and induced. Four-stroke cycle Automobile engines are spoken of as four-cycle engines. This is a shortening of the correct name, four-stroke cycle. A stroke is one complete down or one complete up movement of the piston. There are two downstrokes and two upstrokes to a cycle for the internal combustion engine of this design. A cycle is a round of events, which occurs in a certain fixed order. There are four events in the automobile-engine cycle. These four events correspond to the four strokes. Thus we have the name, the four-stroke cycle, or the shortened and more used term, the four-cycle engine. On the first stroke of any cycle within an engine, the first event or operation is the drawing in of air and fuel through the carburetor. This occurs on the downstroke of the piston. The second operation is compressing or squeezing together of the fuel charge drawn in on the first downstroke. The compressing of the fuel occurs on the first upstroke of the piston. The fuel is fired at the end of this stroke, and the third event or operation is under way. The piston is forced downward on the second downstroke. On the second upstroke, it drives the burned gases before it, and they pass out of the cylinder. The order, then, of the four strokes of the cycle is this: First downstroke, intake; first upstroke, compression; second downstroke, power ; second upstroke, exhaust. The cycles occur as follows: Intake, compression, power, exhaust, again and again. Valve action Pistons are moved up and down on the strokes by the crankshaft throw. Each revolution of the crankshaft gives two strokes of the piston. For four strokes (two down, two up) the crankshaft must turn twice. The flywheel, attached as it is to the crankshaft, turns through two complete revolutions for each four strokes of the piston. This means, since there are 24 teeth in the crankshaft gear and 48 teeth in the camshaft gear, that the camshaft will turn half as fast as the crankshaft. The camshaft (left) carries two cams for each cylinder. It turns once for each four strokes of the piston. Each cam has a valve lifter resting on it. Each cam lifts the lifter resting on it, once for each full revolution of the camshaft. Each valve is thus lifted once for each four strokes of the piston or two revolutions of the crankshaft. The time at which each valve is lifted is called "engine or valve time." The intake valve (right) must start to open as intake (first down-stroke) starts. It must close when compression (first upstroke) starts. Both valves must remain closed during compression and power (first upstroke and second downstroke). The exhaust valve must open at the beginning of the exhaust stroke and remain open to the finish of this, the second upstroke. The intake valve opens on the first stroke to let the fuel charge in. The exhaust valve opens on the fourth stroke to let the burned gases out. Length of strokes While the four strokes of the piston are bound to be of equal length, it is not true that the same amount of piston travel is assigned to each stroke. As a matter of fact, there is a wide difference in the degrees of crankshaft travel of the four operations. There are 360 deg. to each circle. A flywheel turning twice will then travel through two circles, or 720 deg. This number of degrees is then divided between the four strokes of the cycle. A full stroke of the piston is 180 deg. Four full strokes of the piston represent 720 deg. flywheel travel. Roughly speaking, the operation corresponds to the piston stroke. The setting of the cams on the shaft and the shape of the cam determines the length of time the valve will be held open, as well as its moment of opening and closing. In most engines, this occurs about as follows: The starting point for all figuring in engine valve timing is t.d.c. (top dead centre). This refers to the t.d.c. for the first piston in its cylinder. This position is often marked on the flywheel.

This may or may not be a good post, but it's just way too long to read.

http://www.google.co.uk/search?q=how+does+the+four+stroke+engine+work&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-GB:official&client=

karthik_003, If you could convert heat energy effectively to electrical energy, you probably would not need the main engine at all.

karthik_003, If you could convert heat energy effectively to electrical energy, you probably would not need the main engine at all.

if you didnt have the main engine where are you getting the heat from ?

>>if you didnt have the main engine where are you getting the heat from ?<<

Burning fuel.

drifting away from the original thread a bit.

although it depends on how efficiently the power is extracted if the cells can convert more than 24% into electricity then yes it would be an improvement over IC engine

and on sunny days you could focus suns heat onto cell as well

This thread is descending into madness.

We do use the engine's waste heat to warm the interior of the car. This proved to be very efficient use of that wasted heat!

A few months ago, there was a report of an IC that could generate a current from any heat differential. If that ever happens, it would be easy to use the IC's current to charge a battery.

I know this may be off topic, but it is always amusing. Love to ask an engineering minded person what time is it and they go on to exlpain how the watch is made. No disrespect intended just a little humor.

yes they do go on a bit dont we

Why anyone would chose this website for an explanation of how a 4-stroke engine works is quite beyond me. There must be a billion references out there. Why anyone would chose to actually answer that request with a small book size explanation is even further beyond me.

I feel tempted to pose the question: "How does a wheel work?"

how does the wheel work. we will get round to that as we roll along