Spark plugs generate a high voltage spark to ignite the fuel in an engine. However, not all engines use spark plugs for their ignition. That brings us to the question.
Which engine uses a spark plug? Gasoline engines, both two-stroke and four-stroke, use spark plugs in them to ignite the fuel mixture. Diesel engines, on the other hand, do NOT use spark plugs for ignition.
Rather, diesel engines use a higher compression ratio in the combustion chamber to ignite the diesel fuel mixture.
Now, let’s deep dive into these engines using spark plugs and how their usage is in motorcycles and cars.
Which engine uses a spark plug?
Gasoline engines use spark plugs in them.
All gasoline engines need spark plugs to ignite the gasoline fuel mixture for combustion.
Without the spark plugs, the gasoline engines won’t be able to burn the fuel and hence no combustion – and hence, no running of your vehicle.
Gasoline engines rely on spark plugs to start the ignition through the electric spark. If the spark plug is not there, or not generating the spark, the engine won’t run at all.
That’s why spark plugs are one of the first things to be inspected if the engine is not starting in a motorcycle.
Gasoline engines – both two stroke and four stroke – use spark plugs. These engines will not at all run if the spark plug is not working properly.
What does a spark plug do in an engine?
A spark plug is used to generate a high voltage spark in the engine. This spark ignites the fuel mixture paving way for the combustion process.
The spark plug produces the spark in the range of 15,000 to 20,000 volts. Such a high voltage spark helps in the easier ignition of gasoline within the engine.
Once the spark plug ignites the fuel mixture, the combustion takes place with the burning fuel producing energy.
The energy produced in the engine is then utilized for n number of purposes – ranging from motorcycle running to powering the electrical components to running the camshaft to charging the battery. All because the spark plug decided to create a spark ;).
Do all motorcycles have spark plugs?
All motorcycles that run on fuel have spark plugs.
Motorcycles invariably use gasoline engines (we are speaking of fuel run motorcycles of course). And gasoline engines need spark plugs for combustion.
The key here is not motorcycles but gasoline engines. Spark plugs are a vital and required component in all gasoline engines.
Now, since motorcycles only use gasoline engines, they are bound to have spark plugs with them. In short, motorcycle engines rely on spark plugs to ignite gasoline. The fuel, once ignited, burns to generate power for the motorcycles.
You can also look at this as one of those logical conclusions thing in schools.
A. All motorcycles have gasoline engines (fuel run motorcycles of course).
B. All gasoline engines have spark plugs.
Conclusion: All motorcycles have spark plugs!
Do diesel engines use spark plugs?
Unlike gasoline engines, diesel engines do NOT use spark plugs for ignition.
Rather, diesel engines use a higher compression ratio to ignite the diesel in the engine. Compressing the fuel mixture also increases the temperature in the engine combustion chamber. Thus, as a result, this high compression ignites the fuel mixture for engine combustion.
Since diesel engines rely entirely on compression to ignite the fuel mixture, they typically have a higher compression ratio.
A typical diesel engine will have a compression ratio of 22:1. Compare that to a gasoline engine – which usually has a compression ratio of 8:1. That’s almost 3x increase in compression.
To round up this discussion:
- Diesel engines do NOT have spark plugs.
- Diesel engines have a high compression ratio to ignite the fuel mixture.
Do all cars have spark plugs?
All cars do not have gasoline engines in them. They run on diesel engines as well depending on the make. And hence, not all cars contain spark plugs.
Motorcycles, at least the ones running on fuels, only use gasoline engines. But, cars run on either gasoline engines or diesel engines as well – depending on the make and the model.
So cars running on gasoline engines will have spark plugs in them since, you know, gasoline engines need spark plugs.
Cars running on diesel engines, on the other hand, will NOT have spark plugs since there is no need for them in diesel engines.
In essence, all cars do not have spark plugs. While the cars running on gasoline engines have spark plugs in them, the cars running on diesel engines will not.
Glow plugs in diesel engines
As discussed earlier, diesel engines do not need spark plugs. So, they don’t have spark plugs installed in them.
But, diesel engines do have a component called glow plugs installed in them – right where the spark plugs are in gasoline engines.
Now, what does a glow plug do in a diesel engine?
The glow plug heats the diesel combustion chamber. This comes in handy whenever there are cold weather conditions outside and the chamber is too cold to start with only the compression.
Glow plugs help here by preheating the diesel combustion chamber. As a result, the diesel fuel mixture in the engine gets ignited easily through the piston compression – thus, generating energy for the engine.
Spark plugs and glow plugs – what’s the difference?
First, spark plugs are used in gasoline engines, and glow plugs are used in diesel engines. These are exclusive usage and cannot be interchanged.
That is, you won’t find spark plugs in a diesel engine and vice versa. Their roles, although look similar, are actually different in their respective engine types.
Second, spark plugs are the source of ignition in gasoline engines. Glow plugs, on the other hand, help in the ignition but it is the high compression that drives ignition in diesel engines.
Third and lastly, spark plugs generate an electric spark of 15,000 to 20,000 volts to ignite the gasoline in the engines.
Glow plugs have a heating element tip which is used to preheat the combustion chamber. This helps in the easier ignition of the diesel in the engines.
While spark plugs generate an electric spark to ignite the fuel, glow plugs heat the chamber to facilitate fuel ignition.
To Summarize
- Only gasoline engines use spark plugs in them. They need spark plugs to ignite the gasoline fuel mixture for combustion.
- All motorcycles that run on fuel have spark plugs.
- Unlike gasoline engines, diesel engines do NOT use spark plugs for ignition. Diesel engines use a higher compression ratio to ignite the diesel in the engine.
- Not all cars have spark plugs. While the cars running on gasoline engines will have spark plugs in them, the cars running on diesel engines will not.
- Although diesel engines do not have spark plugs, they do have a component called glow plugs installed in them – right where the spark plugs are in gasoline engines.
- Glow plugs are used to preheat the combustion chamber. This helps in the easier ignition of diesel in their engines.
