Double Platinum Spark Plugs (Functions, Advantages, Uses)

Double Platinum Spark Plugs (Functions, Advantages, Uses)

Double platinum spark plugs are confusing.

They don’t fit the conventional spark plug functioning and yet are an extension of single platinum spark plugs.

So, what exactly are double platinum spark plugs? Spark plugs with platinum-coated electrodes that ignite twice in a combustion cycle are called double platinum spark plugs. The spark ignition happens both during the compression stroke as well as the exhaust stroke.

Double platinum spark plugs are not a popular spark plug type used in motorcycles. Or in any automobiles for that matter. But, they are the preferred spark plugs in machinery using wasted spark systems.

To get a more detailed view, let’s dig into the details.

What Are Double Platinum Spark Plugs?

Spark plugs with platinum electrodes and igniting twice in a single combustion cycle are called double platinum spark plugs. Obviously, the spark plug is made of platinum for spark ignition. And the two ignitions happen once during the compression stroke and another during the exhaust stroke.

In a typical single spark plug, the ignition happens only once during the compression stroke of the engine.

As for why there is a double spark, the spark during the exhaust stroke does nothing in terms of power generation in the engine. This exhaust spark is popularly dubbed as a ‘wasted spark’.

The utility of this wasted spark is not found in conventional distributor ignition systems. But, a wasted spark ignition system does find it useful though.

Wasted Spark Ignition System

A wasted spark system is one of the ignition systems that require two sparks in a cycle of four stroke combustion engines. One spark during the compression stroke. And the other in the exhaust stroke.

The second spark ignited in the exhaust stroke has no impact on the power generated, hence the name ‘wasted spark’.

However, wasted spark ignition has a lower number of components required when compared to other ignition systems.

The wasted spark apparently helps the ignition system in running smoothly without the requirements of too many components.

The wasted spark ignition is not common though. They are typically found in machines like lawn mowers. Rarely do you find wasted spark systems in automobiles.

Advantages Of Double Platinum Spark Plugs

The main advantage of double spark plugs is in the spark system it relies on – the wasted spark ignition system.

The wasted spark system does not require too many components and has a simplified mechanical arrangement.

Another advantage, although debatable and unproven, is that double spark plugs ignite any unburnt fuel during the exhaust stroke.

Whenever the engine receives a rich air-fuel mixture, there will be unburnt fuel even after the combustion. The wasted spark during the exhaust stroke might burn this fuel and let the exhaust gases flow easily out of the exhaust.

In addition, double platinum spark plugs provide all the advantages that a platinum spark plug provides. They have good longevity and life span. The spark plug can last up to 60,000 miles – far higher than a typical copper spark plug’s lifespan.

Platinum spark plugs also have a high operating temperature owing to the high melting point (1768 celsius). Most importantly, platinum spark plugs do not allow carbon deposit formation easily on them. This lowers the frequency of changing and replacing the spark plugs. The platinum coating on the electrodes makes any deposit formation difficult.

Disadvantages Of Double Platinum Spark Plugs

The main disadvantage of double platinum spark plugs is that they reduce the engine power output and the performance slightly.

The second disadvantage is double platinum spark plugs are suitable only for wasted spark ignition systems. And wasted spark systems are rarely seen in automobiles.

The distributor spark ignition is what most automobiles use. As a result, double platinum spark plugs are not what most automobile user guides recommend as a suitable spark plug.

To sum up the cons, double platinum spark plugs are a hindrance in terms of performance. And, they are not the spark plugs your vehicle manufacturer prefers or recommends.

Double Platinum Spark Plug Uses

Now that we have an idea of what double platinum spark plugs are and what are its pros and cons, let’s discuss their usage.

First, double platinum spark plugs are almost exclusively used in wasted spark ignition systems. As a result, double spark plugs are used only in those systems which use wasted spark systems. Of course, spark plugs are used in gasoline engines only.

You will typically find double platinum spark plugs in pieces of machinery like lawn mowers and a few generators.

Motorcycles typically do not use double platinum spark plugs. However, there might be a few models that can accommodate double platinum plugs in their engines. Still, it would be a rare sight to find double platinum spark plugs used in a motorcycle engine.

Single vs Double Platinum Spark Plug – Which Is Better

Single platinum spark plugs are the better spark plugs for motorcycles. They are better than copper spark plugs in terms of reliability and longevity. Double platinum spark plugs are usually not recommended for motorcycles.

Platinum spark plugs, in general, are considered a better alternative than copper spark plugs. And a poorer alternative to iridium spark plugs. For more details, here is a post on different types of spark plugs.

However, double platinum spark plugs are better for engines using wasted spark systems.

There is no one universal better solution between the single and double platinum spark plugs. The usual norm is to go for a single platinum spark plug for automobiles – especially motorcycles.

To Summarize

  • Spark plugs with platinum electrodes and igniting twice in a single combustion cycle are called double platinum spark plugs.
  • The two ignitions happen once during the compression stroke and another during the exhaust stroke.
  • The main advantage of double spark plugs is in the spark system it relies on – the wasted spark ignition system.
  • The wasted spark apparently helps the ignition system in running smoothly without the requirements of too many components.
  • The double platinum spark plugs are used in pieces of machinery like lawn-mowers and generators.
  • Double platinum spark plugs are usually not recommended for motorcycles.