Improved Efficiency / Combustion Engines Explosion

[chatelot16]

slowly it's relative ... each engine has an optimum speed depending on its size

when a small engine rotates too slowly a too high proportion of the heat of combustion is lost in the cylinder wall: a small 200cm3 engine like genset is at the right speed at 3000 rpm ... turn slower would be bad

higher speed improves efficiency by reducing heat loss, but increases pressure drop to pass through the valve

the good compromise is between thermal loss if it's too slow, and rolling in the valve if it's too fast

to put 4 valve per cylinder is a way to be able to turn faster

[Flytox]

It also seems to me that a slow-running engine will have better performance than a fast-running engine, although that does not seem to be verified in practice ...

Much less mechanical loss when turning slowly but also a lot of heat loss through the walls. So a "good" compromise is a "huge" displacement like on big boats. (the exchange surface (cylinder head) / displacement ratio much better for large displacement. For our "small" car engines .... it's more difficult. ... it is necessary to remain light and in addition the real need of power is ... weak.

[Remundo]

there are complex and contradictory effects that make the optimal specific consumption is at full load and mid-speed.

The best engine performance is a wise compromise of many things and it is finally quite empirical: we see the engine-bed that it does not work well on very low speeds (thermal leakage and grazing because the sequence of engine times is struck ), and not at high speeds (difficulty filling, high friction power and not enough time for the explosion / relaxation ...)

Likewise, increasing the effective average pressure (PME) too much can lead to increased piston / liner friction.

In short, it's complicated, and a simple rule: full load half-speed = the best engine performance.

[AurélienRC]

Hello,

I want to help you, let's say try to give you ideas or participate a little in this project. Your ideas seem relevant to me, but most of them have still been picked up and already exist as a high energy ignition or have a high compression ratio. The advantage I see there is bioethanol (for example), which would greatly increase the ignition advance torque-compression ratio, and therefore increase the efficiency in its purely thermodynamic definition. I even believe that the ignition and the compression ratio are the first two parameters to take into account, where it would be necessary to "start" on a guinea pig like a 205 junior ...

There are other avenues to explore too, such as what was done on the Peugeot 207 for example, as the variable oil pressure (the oil pump is a big energy consumer), the disengagement of the pump. water in warm-up phases or things like that.

This is also why not consider a reduced friction segmentation, a completely electronic and cartographic ignition and not hall effect, a variable camshaft setting, and an overall decrease in internal friction ... A whole bunch of tracks to explore what.

[iridium]

Hello everyone.

A lot of complicated things here.
It has been some years since I tan my colleagues to achieve a simple system that would increase the fuel efficiency of a gasoline engine.

Since now 3 months we are working on a motorcycle ECU.
The goal is to be deceived and make her believe that she and riding a motorcycle that works.
While the main signals are sent via circuit board that simulates different sensor.
From this base I wish that we seek to realize the idea attached.

The thing is simple.
Suitable fuel compression.
Mechanically got too complicated.

So the idea would be to definitely tablet have a compression ratio of 13/1 for example. "An RV that requires the use of high octane fuel."

with an unsuitable fuel it's an idea of ​​shit.
With a fuel adapted to this use is very expensive so it would be an idea of ​​shit.
Unless

The idea is to install a knock sensor on the cylinder head and a thermocouple on the exhaust.
For recording a rattling or a self-combustion thanks to the gas bcp warmer.

Depending on the results read on the sensors a motorized throttle in series on the main throttle closes or opens independently of the main throttle to limit the air mass that enters and therefore via the cycle of rochas reduces the temperature of the mixture which is compressed at a lower pressure and therefore a lower temperature because a lower air mass has been admitted.

The ECU is deceived because its TPS is mounted on the motorized throttle and a lambda TPS is used on the main throttle.

The lambda TPS allows to know our assembly the position of the motorized throttle that is desired.
Our assembly controls the motorized throttle to follow the same displacement as the main throttle.
The main time on the motorized butterfly allows the ECU to know the amount of fuel injected.

If an abnormally high temperature or pinging is detected the motorized throttle closes independently of the main throttle.

which limits the mass of air absorbed and therefore the temperature at the end of compression.
the system adapts permanently.

Here is the basic principle that needs to be developed.

PS:
It can even push to restart the engine the next morning with the latest correction recorded by adding to the assembly a sensor that would analyze the tank level and reset the values ​​in case of fuel level that would have changed.

[chatelot16]

it is not very useful to increase the mechanical compression ratio: simply changing the advance at ignition gives a certain freedom of adjustment

when the engine is cold and the fuel has a high octane number, it can increase the ignition advance to seek the maximum efficiency ... when the terminal is exceeded, the start of combustion makes the pressure rise too high and there is not only propagation of combustion but self ignition mass of what remains: rattling: it is necessary to reduce instantly the advance

I imagine that the ecu modern car all know how to do that ... alas I do not have

[iridium]

approaching the autoignition temperature was a higher flame front velocity and thus a higher PME.
The torque is proportional to this SME, so it increases with the power for a same amount of gas.

Which means that for the same acceleration you inject less fuel.
Which means to maintain a constant speed, you inject less fuel.

In short, more power for the same amount of fuel improves fuel efficiency.
The rest goes on the accelerator pedal.

explain to me if I am wrong?

[chatelot16]

we almost agree ... but the compression ratio of a gasoline engine is far from risking to self ignition: it is supplemented by the advance ignition which increases the pressure and puts the maximum useful pressure just after the PMH ... it is conventional to adapt the engine to the octane number just with the ignition advance

[iridium]

We agree on the advance, but it will make you gain very little.

Whereas for 30% additional compression, at the same mixing amount the torque increases by almost 30%.

[Christophe]

Whereas for 30% additional compression, at the same mixing amount the torque increases by almost 30%.

Is that so? Can you show us? Because it seems a bit fast here ... as an approximation ...