Potential damages to be caused by "tope" in engine?

[Howard Roark]

Tsips!

Medyo tumotope ang makina ng 6 month old altis ko. Ano ang possible na maging implications sa makina? Malapit na kasi PMS, ok lang kaya na hintayin ko na? BTW, V-power na ang gas ko....

TIA!

[niky]

What kind of tope? Firsthand or secondhand Altis? How many kilometers on your odometer?

"Tope" for a six month old car isn't good... you may have a sensor or electrical issue, or problems with your fuel pump or injectors... but without seeing the car or hearing it run, it's hard to tell.

Better bring it in for PMS right away... even if you haven't hit the pre-requisite number of months or kilometers, if you've been driving in traffic a lot, you might already need PMS anyway.

[Howard Roark]

What kind of tope? Firsthand or secondhand Altis? How many kilometers on your odometer?

"Tope" for a six month old car isn't good... you may have a sensor or electrical issue, or problems with your fuel pump or injectors... but without seeing the car or hearing it run, it's hard to tell.
.

Its a brand new altis E, acquired june 2007. The tope sound is from the engine, around 2100 rpm. Sensor problems? I cant bring the car to the casa right now. Christmas rush, wifey's due anytime now... I need inputs on potential problems this might cause

[niky]

Does it cough? Does it backfire? Does it hesitate when you're accelerating? Does this happen when it's cold or when it's hot? If it happens when it's hot, it's more likely a sensor. If it happens when it's cold, it might be something else, vacuum line, fuel, etcetera...

As long as it's not eating oil (check religiously every morning before you start the car and monitor possible oil loss), it's not a big issue, but you have to at least report it to Toyota for it to be considered under warranty...

It's possibly a sensor issue or a fuel delivery issue that's causing hesitation. I'm not familiar with the Altis engine, so I can't tell you, off-the-bat, what it might be with any certainty.

[suv]

Ano pala ibig sabhin ng "tope"

[Odiong929]

Wig?! ... Anyway, its really hard to tell the real reason behind. Its possibly one of those things as mentioned by Niky. Plus the conditions during its occurence. Asking the Casa by phone maybe would help.

[washburn]

dalhin na sir sa casa yan under warranty pa naman e

[Howard Roark]

Does it cough? Does it backfire? Does it hesitate when you're accelerating? Does this happen when it's cold or when it's hot? If it happens when it's hot, it's more likely a sensor. If it happens when it's cold, it might be something else, vacuum line, fuel, etcetera...

Its happening even when the car is hot/cold. It's quite hesitating acceleration (medyo hina humila) when it reaches that rpm but does not backfire.

As long as it's not eating oil (check religiously every morning before you start the car and monitor possible oil loss), it's not a big issue, but you have to at least report it to Toyota for it to be considered under warranty...

Got to check the oil, I thought its not an issue coz my car's still new.

If I may our mechanical henyos out there... where is this sound coming from? Cam banging over something due to insufficient fuel, misfiring of the sparkplugs, camshaft rattling? Where is the possible wear or tear that may arise due to this sound?

I am assuming that its fuel/timing problem coz I often hear this sound from carb type taxis na "sinakal" or LPG fueled cars that has timing problems.

Thanks!

[mazingerZ]

Sir niky,

Please elaborate further about tope. I am not aware of this term. Thanks. and God Bless.

[Galactus]

Eto, from Wikipedia:

Engine knocking
From Wikipedia, the free encyclopedia
(Redirected from Engine knock)

Knocking (also called pinking or pinging)— colloquially detonation—in internal combustion engines occurs when combustion of the air/fuel mixture in the cylinder starts off correctly in response to ignition by the spark plug, but one or more pockets of air/fuel mixture explode outside the envelope of the normal combustion front. In non-diesel combustion engines, the fuel-air charge is designed to be ignited by the spark plug only, and at a precise time in the piston's stroke cycle designed for the engine. When Detonation (Knocking) occurs two or more combustion fronts will exist and their resultant collisions produce a sudden rise in cylinder pressure and a shock-wave which will reverberate around the cylinder[1]. The peak of the combustion process no longer occurs at the optimum moment for the four-stroke cycle. The resulting shock-wave reverberates in the combustion chamber, creating the characteristic metallic "pinging" sound, and pressure increases catastrophically. It can range from hardly noticeable to complete engine destruction.

Contents [hide]
1 Normal combustion
2 Detonation
3 Consequences of Knocking
4 Pre-ignition
5 References
6 External links



[edit] Normal combustion
Under ideal conditions the common piston internal combustion engine burns its fuel air mix in the cylinder in an orderly and controlled fashion. The combustion is started by the spark plug some 15–40 crankshaft degrees prior to TDC (top dead center, the point of maximum compression). This ignition advance allows time for the combustion process to develop peak pressure at the ideal time for maximum recovery of work from the expanding gases. This point is typically 14–18 crankshaft degrees ATDC (after top dead center).

The spark plug produces an electrical spark that jumps a small gap from its center electrode to its ground electrode. This spark, if the air/fuel mix is within the flammable range for the fuel, initiates combustion. The initial phase forms a small kernel of flame approximately the size of the spark plug gap. For the first few milliseconds of the combustion process, this flame kernel is struggling to survive, producing only slightly more heat than is necessary to continue the combustion process. As it grows in size its heat output increases allowing it to grow even faster.

After this early slow burn phase passes, the flame kernel grows much faster expanding rapidly across the combustion chamber. This growth is due to the travel of the flame front through the combustible fuel air mix itself and due to turbulence rapidly stretching the burning zone into a complex of fingers of burning fuel air that have a much greater surface area than a simple spherical ball of flame would have. This greatly accelerates the combustion process.

In normal combustion, this flame front moves throughout the fuel air mix at a rate characteristic for the fuel-air mixture. Pressure rises smoothly to a peak, burning nearly all the available fuel then falls as the piston descends. In normal combustion this produces a rapid increase in cylinder pressure as the piston passes TDC and begins to move down the cylinder. As mentioned above in a properly tuned engine the maximum cylinder pressure is achieved a few crankshaft degrees after the piston passes TDC, so that the increasing pressure can give the piston a hard push when its speed and mechanical advantage on the crank shaft gives the best recovery of force from the expanding gases.


[edit] Detonation
The fuel/air mixture is normally ignited slightly before the point of maximum compression to allow a small time for the flame-front of the burning fuel to expand throughout the mixture so that maximum pressure occurs at the optimum point. The flame-front moves at roughly 33.5 m/second (110 feet/second) during normal combustion[citation needed]. It is only when the remaining unburned mixture is heated and pressurized by the advancing flame front for a certain length of time that the detonation occurs. It is caused by an instantaneous ignition of the remaining fuel/air mixture in the form of an explosion. The cylinder pressure rises dramatically beyond its design limits and if allowed to persist detonation will damage or destroy engine parts.

A non conventional engine that makes use of detonation to improve efficiency and decrease pollutants is the Bourke engine.

Detonation can be prevented by:

The use of a fuel with higher octane rating
The addition of octane-increasing "lead", methylcyclopentadienyl manganese tricarbonyl (MMT), isooctane, or other antiknock agents.
Increasing the amount of fuel injected/inducted (resulting in lower Air to Fuel Ratio)
Reduction of cylinder pressure by increasing the engine revolutions (lower gear), decreasing the manifold pressure (throttle opening) or reducing the load on the engine, or any combination.
Reduction of charge (in-cylinder) temperatures (such as through cooling, water injection or compression ratio reduction).
Retardation of spark plug ignition.
Improved combustion chamber design that concentrates mixture near the spark plug and generates high turbulence to promote fast even burning.
Use of a spark plug of colder heat range in cases where the spark plug insulator has become a source of pre-ignition leading to detonation.
Water injection into the cylinders to reduce cylinder head temperature.
Correct ignition timing is essential for optimum engine performance and fuel efficiency. Modern automotive and small-boat engines have sensors that can detect knock and retard (delay) the ignition (spark plug firing) to prevent it, allowing engines to safely use petrol of below-design octane rating, with the consequence of reduced power and efficiency.

A knock sensor consists of a small piezoelectric microphone, on the engine block, connected to the engine's ECU. Spectral analysis is used to detect the trademark frequency produced by detonation at various RPM. When detonation is detected the ignition timing is retarded, reducing the knocking and protecting the engine. See also Automatic Performance Control (APC).


[edit] Consequences of Knocking
Engine knocking has disastrous consequences for the engine, since it leads to the catastrophic wear of the combustion chamber walls, through particle wear for moderate knocking, to welding for serious knocking. This is due to the contact between those walls and high temperature gases resulting from the unwanted explosion. The processes also lead to a 'knocking' noise for the engine, that give its name to the phenomenon.


[edit] Pre-ignition
Pre-ignition is a different phenomenon from detonation, explained above, and occurs when the air/fuel mixture in the cylinder (or even just entering the cylinder) ignites before the spark plug fires.