What is the purpose of porcelain spark plugs?

Porcelain Spark Plug Insulators The first spark plug insulators used something known as refractory porcelain. This is a ceramic made out of a high-quality clay that can survive really-high temperatures. When it heated up, it also did not expand as much as the metal in the electrode or plug body.

What is a projected spark plug?

A projected spark plug protrudes into the combustion chamber further and provides higher ignitability and improved performance. A projected spark plug in effect produces a spark in the middle of the circle (or combustion chamber) allowing for an even flame spread.

Why do spark plugs have ceramic?

The plugs use an insulator, generally made of ceramic (porcelain) to isolate the high voltage running down the electrode, making sure that the spark happens at the tip of the electrode (inside the engine’s combustion chamber) and not anywhere else on the spark plug.

Does porcelain break glass?

Sure thing, buddy. Now, disregarding all of that silliness, the point of the video is that a very small piece of porcelain can actually break the glass very easily. As the host explains, that is because side car windows are made out of tempered glass, which is resistant to bigger, blunt-force hits.

Will the ceramic from a spark plug break glass?

Annealed glass, i.e. ordinary window glass, is the least resistant; any ceramic, for example a brick, will break and shatter it. Golf balls, baseballs, and sometimes footballs will break and shatter it too. Tempered glass, such as used in the side and rear widows of cars, is the most impact resistance.

What is a resistor plug?

Resistor plugs were developed in the 1960s to suppress some of the spark energy, thus lowering RFI to an acceptable level. Most resistor spark plugs use a monolithic resistor, generally made of graphite and glass materials, to filter the electrical voltage as it passes through the center electrode.

What is a projected insulator?

Projected insulator sticks the insulator more into the combustion chamber. My understanding is non-projected are for forced-induction (turbo or supercharged) and projected are for normally aspirated. Non projected – the tip of the centre electrode is more or less level with the end of the threaded shell.

What is spark plug ceramic made of?

The main part of the insulator is typically made from sintered alumina, a very hard ceramic material with high dielectric strength, printed with the manufacturer’s name and identifying marks, then glazed to improve resistance to surface spark tracking.

What kind of ceramic is in spark plugs?

Raw Materials The electrodes in a spark plug typically consist of high-nickel alloys, while the insulator is generally made of aluminum oxide ceramic and the shell is made of steel wire. Selection of materials for both the electrodes and the insulator have consumed much research and development time and cost.