Questions tagged [engines]

The tag has no usage guidance.

Filter by
Sorted by
Tagged with
0
votes
3answers
84 views

Replicate stepper motor with gasoline engine

For those unaware of what a DC stepper motor is, it boils down to an electronic motor where the rotation can be precisely controlled, i.e. you can control the rotation of the motor in fractions of a ...
-1
votes
0answers
15 views

Calculating (transient) rate of cycles of practical thermodynamic engines (turbojet, multi-cylinder car engines etc..)

I already asked this on Physics Stackexchange but to no avail. Thought this forum is a better place to ask this. I tried to make a plan for a turbojet engine with my physics knowledge and I'm stumped ...
-1
votes
2answers
22 views

Could you use anything as a fuel source for an engine or motor, if it's designed to use that specific type of fuel?

By anything I don't mean to put some random liquid in a car engine, but is it possible to design and build an engine or motor that could use something like tea or orange juice for it's fuel? I know it ...
5
votes
1answer
113 views

In a diesel engine, does more heat leave the engine through the tailpipe or the radiator?

Diesel exhaust is hot, and there's a lot of it. Diesel radiators also get pretty hot. In a typical diesel engine, which one is dissipating more heat? EDIT: In response to a request for specificity ...
-1
votes
2answers
24 views

Relation between engine size and its power to weight ratio

Is there a relation between engine size and its power to weight ratio? For example if you shrink the engine to half the size will it have exactly half the power?
-1
votes
1answer
20 views

Understanding a Variable Lift Valve Train Patent

So my father has this patent, and I'm not entirely sure how a certain aspect of it is supposed to be working. I understand how it can be useful, but I don't understand how such a seemingly simple ...
13
votes
8answers
4k views

Is there a reason (in terms of the physics involved) why it is better to push start a car in 2nd gear rather than 1st?

I am struggling to understand why it is recommended to push start a car in 2nd gear rather than 1st - in terms of the physics involved, I fail to see a reason why this would be the case. I have ...
1
vote
0answers
17 views

Ignoring Mechanical Material Properties and Design Implications, in a Compressor, does the Thermal Density of the Blades Affect Efficiency?

Consider an ideal adiabatic compressor, ignoring the remainder of the thermodynamic cycle. In this case, the heat flow q into and out of the compressor itself is zero, by definition of adiabatic ...
2
votes
3answers
70 views

Why do custom engines typically specify a type like “Ford” or “Chevy”?

I notice that when custom car engines are sold they nearly always have a big name type name like "Ford" or "Chevy". Is this because the block and crankshaft comes from those companies and the custom ...
0
votes
0answers
77 views

When does the minimum temperature in a four-stroke cycle occur inside the engine cylinder?

I've checked on quite a few places on the net and some say it occurs at the beginning of suction stroke and others say at the end of suction stroke. I believe it to be at the end of suction stroke ...
0
votes
1answer
19 views

Relationship between Heat Flux and Engine RPM

I'm doing a project that involves knowing the average steady-state heat dissipation rate of a single cylinder air-cooled engine (through the engine wall and fins) at a given RPM. The problem is that I ...
0
votes
1answer
31 views

What developments made diesel engines suitable for personal cars in the 1970s/1980s?

Both diesel and gasoline engines were developed in the late 19th to early 20th century. Diesel engines were for the most part of the 20th century used mostly for large applications in ships, trains, ...
2
votes
1answer
38 views

Effect of Pressure on Combustion efficiency (of hydrogen) in excess air

Can somebody explain relation between combustion efficiency and pressure in lean mixtures using any kind of chart or mathematical equations? At first glance I thought, combustion efficiency increases ...
0
votes
2answers
46 views

How do turboshaft engines maintain a constant rpm regardless of load?

I understand that most turboshaft engines tend to run at (or close to) their most efficient rpm all of the time, and it is the load that is changed e.g. the pitch of the blade pitch on helicopters. ...
0
votes
1answer
59 views

What are the non-practical features of a sterling engine that cause the internal combustion engine to be used instead?

What are the non-practical features of a sterling engine that cause the internal combustion engine to be used instead (in a car)? (e.g. price, size, the power to weight ratio, etc.) Can you name any ...
0
votes
0answers
26 views

PLEASE ANSWER Sterling vs Combustion Engine

This may be difficult to answer but, theoretically, if you had a car with a sterling engine that produces say approximately 300 horsepower how much of any specific heat source would need to be used if ...
1
vote
3answers
32 views

Efficiency of an engine

What is meant by thermodynamic efficiency of an engine? and what are the factors that affect the thermodynamic efficiency of a diesel engine?
1
vote
2answers
181 views

How do external irreversibilities decrease the efficiency of thermodynamic cycles?

In gas power cycles, one mentioned that: The Carnot cycle is both externally and internally reversible. Therefore making the Carnot cycles more efficient than other practical cycles. Question: ...
1
vote
2answers
106 views

How difficult would it be to build an entire engine (block and all) in 16th century conditions?

I was ruminating over A Connecticut Yankee in King Arthur's Court. In the book, a trained American engineer goes back in time and creates guns. The book itself predates tanks, but one could imagine ...
-2
votes
3answers
131 views

Inlet of an ICE [closed]

What is wrong with totally replacing the inlet of a piston engine with a surgical mask?As surgical masks get rid of about 80% of air impurities and dusts.
2
votes
3answers
1k views

Manual transmission: Why downshifting is less smooth than shifting up?

Today while driving I had to make a quick shift to a lower gear that was not as smooth as it should've been. I've been taught that while shifting to a lower gear you have to be more careful when ...
-2
votes
1answer
1k views

What is Inlet-valve Mach index?

What is the meaning of this statement "In a reciprocating engine the flow of intake charge takes place through the intake valve opening which is varying during the induction operation. Also, the ...
1
vote
0answers
276 views

Detergency and dispersancy

Abstract:The detergency property in oil comes from a chemical additive called detergent which has a property of preventing the deposition of carbon deposits and wash it away. There is also this ...
2
votes
1answer
197 views

What's the slowest airflow speed a ramjet could work?

Thinking experiment about a flying device having the fewest moving parts, whats the slowest cruise speed achievable using a ramjet, no matter the scale of this device. Working altitude is troposphere. ...
0
votes
3answers
1k views

Is torque produced at the crank of an engine lower than at the wheels?

Im specifically referring to motorcycle engines, but for arguments sake a car engine wouldn't matter either Say 100Nm was measured at the wheel using a rolling dyno, then based on the reduction ...
0
votes
1answer
165 views

Why aren't modern pistons circular?

I'm trying to make most of an engine from scratch (cylinder, crank case, piston). I've been reading about pistons and I've learned that many modern pistons are cam ground--slightly elliptical in shape ...
1
vote
5answers
856 views

Can an electric motor use reciprocating pistons like an internal combustion engine does?

Would it be possible to have an electric motor that uses an electromagnet to force a piston up and down to turn a shaft, similarly to an internal combustion engine, but without burning fuel? Is there ...
3
votes
1answer
84 views

In internal combustion engines, what determines when soft or hard gaskets are used?

I see that 4 stroke engines use hard gaskets at the cylinder heads, whereas two stroke slow speed engines that are used for the propulsion of ships or for production of electricity on land have soft ...
6
votes
1answer
405 views

What makes crosshead bearings hard to lubricate?

Regarding crosshead bearing failure, I have read that at slow speed it is difficult to establish a lubricating film because there is an imbalance between forces due to combustion and forces due to ...
-4
votes
1answer
546 views

Effects of center of gravity very close to rear wheels of a car [closed]

I see some track race cars, especially old ones made in the 1960s-70s, are designed with the heavy components of the car sitting between the rear wheels. In fact, some of old rear-/mid-engine cars use ...
3
votes
2answers
341 views

Why is soot produced in diesel exhaust, since diesel runs lean?

Since diesel runs lean, why is soot produced in diesel exhaust? Soot is carbon particles due to incomplete combustion. But, since diesel runs lean with plenty of oxygen, why does this happen?
1
vote
1answer
262 views

Timing belt transmission with lateral pulley movement

What is the correct way to allow for lateral movement of a timing pulley in a transmission system? For example, there are four pulleys, one of which has to move up and down. Is there standard ...
4
votes
2answers
6k views

How many power strokes per rotation in a 3 cylinder engine?

How many power strokes occur for every complete rotation in a regular 3-cylinder engine? Or in other words, every how many degrees does a new power stroke takes place? Does anyone know please?
0
votes
1answer
78 views

Torque in different car gears?

Recently I have been researching torque and horsepower. I know that the lower the car gear, the more the torque. However, whenever I see specifications of a car, it says : X lb-ft of torque at Y ...
2
votes
1answer
1k views

How Scalable is the Wave Disk Generator Engine

How scalable is the wave disk generator engine? Are there fundamental limits to how large or small the engine can be and if so, what are they? I'm not looking for answers addressing microscale ...
1
vote
3answers
2k views

Why does a radial engine need a master rod?

Why does a radial engine need a master rod? Why can't slave rods be the only rods? Would this spider bearing (around 1:05 in the video) work for an IC engine, why or why not?
1
vote
1answer
76 views

Calculate pneumatic cylinder dimensions from work done

I have a project for which I need a pneumatic cylinder to impart an impact force in such a way that work-done/energy is 4.5 Joules, and the input pressure is 10 bar. How can I solve this so that I ...
10
votes
2answers
2k views

Are small car engines designed to tolerate a higher duty cycle than large car engines?

For simplicity we're going to ignore aerodynamics and vehicle mass for a moment... Are small (around 1 litre) car engines designed to tolerate a higher duty cycle than large (2+ litre) car engines? ...
6
votes
2answers
1k views

Limitations of the cut-off ratio in real-world diesel engines

In an ideal diesel cycle, the cut-off ratio is set by the maximum gas temperature after combustion. That's all fine and good, but in a real-world engine what controls the cut-off ratio, and what are ...
2
votes
0answers
498 views

Calculating engine pressure from measureable quantities

How can I calculate the engine pressure in units of Bars by using torque, the cylinder volume, motor efficiency, and the gear reduction ratio? My values are as follows: ...
2
votes
2answers
330 views

Methods for determining Work of Diesel Engine's Isentropic Process

Air in the cylinder of a Diesel Engine is at $30^o\ $$C$ and $138\text{ kPa}$ in compression. If it is further compressed to 1/18th of its original volume. Which of the following most nearly equals ...
7
votes
2answers
684 views

How efficient are jet engine thrust reversers?

Most reasonably sized commercial aircraft rely on jet engines for propulsion. Upon landing these aircraft use a number of means to come to a stop with the two most important being (I believe) ...
9
votes
5answers
2k views

Why do some diesel engines run on diesel fuel and others on fuel oil?

Trucks and smaller vehicles with diesel engines run on diesel fuel which looks more or less like kerosene - less flammable than gasoline, low viscosity liquid. However larger diesel engines like this ...