The vast majority of engines use a four-stroke design, where each piston completes four separate strokes to comprise a single thermodynamic cycle. These four strokes are: intake, compression, power, and exhaust.
1. Intake: Beginning at Top Dead Center (TDC), the piston descends within the cylinder. This movement sucks a mixture of fuel and air into the cylinder through the intake port via the intake valve.
2. Compression: Both intake and exhaust valves close and the piston returns to the top of the cylinder compressing the air-fuel mixture into the combustion chamber resident in the cylinder head.
3. Power: Slightly before Top Dead Center (BTDC) the compressed air–fuel mixture is ignited by a spark plug. The piston is forced back down as the fuel mixture is combusted, creating pressure.
4. Exhaust: The piston returns to TDC while the exhaust valve is open, ejecting the burned and unburned fuel-air mixture through the exhaust valve(s). Emissions are composed of the burned and unburned fuel-air mixture.
Power is created by the expanding gasses forcing the piston down at just the right time during the power stroke. If the spark occurs to early, the piston is either still on its way up during the compression stroke or the crank is not far enough past TDC to take advantage of the pressure from the expanding gasses – wasting energy. If force is applied too late, the expanding volume of combustion gasses does not provide enough pressure to generate power. In newer cars, a computer determines how much power is required and adjusts the amount of ignition timing and fuel delivered to minimize fuel usage (MPG) and ensure enough pressure is created by the burned air-fuel mixture to apply the appropriate force to the piston at just the right time – maximizing horsepower and torque.
The Spark Plug
A spark plug creates a spark with the electric current and voltage from the ignition coil to ignite the compressed air–fuel mixture. In most engines, the flow of the air-fuel mixture is targeted to intersect with the space between the center electrode and ground electrode where the spark forms – known as the spark gap. By intersecting the fuel mixture with the spark gap, engine makers attempt to ensure the fuel mixture is ignited quickly by the concurrent spark.
The Pulstar Difference
Unlike conventional spark plugs that dissipate and waste energy, Pulstar Pulse Plugs have a patented capacitor in the core that stores energy from the ignition coil. Immediately before the spark, Pulstar with PlasmaCore Plugs release this energy in a quick and powerful burst, producing more than 5,000,000 watts of peak power which forms an energy-dense and ion-rich plasma field.
The plasma field sensitizes the fuel mixture allowing it to burn more quickly and completely once the spark is formed, creating consistent cycle-to-cycle combustion pressure resulting in a quicker throttle response and higher average horsepower and torque.
A typical capacitor has three parts: a positive plate, a negative plate, and a dielectric media. The positive plate attracts the energy while the negative plate provides it access to ground. The dielectric media prevents the energy from crossing between the two plates, forcing the energy to collect and be “stored” on the positive plate. Eventually, the pressure of the energy builds until it is forced to find another access to ground. The energy is released rapidly, resulting in the delivery of a large amount of instantaneous power over a short period of time – creating a pulse of power.
Pulstar® Pulse Plugs use the solid copper gas seal as a positive plate, slowly accumulating energy delivered by the ignition coil. All spark plugs are electrically grounded by screwing into the engine's cylinder head with its threaded metal shell. In Pulstar® Pulse Plugs, the threaded metal shell acts as the negative plate – giving access to ground. The ceramic insulator found in all spark plugs is also used as part of the Pulstar® capacitor, acting as the dielectric media that prevents energy from crossing from the positive plate to the negative.
Optimal engine performance, increased MPG and reduced emissions are achieved by burning the fuel delivered during the intake stroke more completely during the power stroke. Automotive manufacturers take great pains to effectively present the air-fuel mixture to the spark gap in an attempt to improve fuel burn rate and prevent misfires (failure to ignite the fuel).
To assist automotive manufacturers in this goal, spark plug makers have moved from a wider electrode that lasts longer to a fine wire precious metal tipped electrode, such as iridium or platinum. A larger electrode tends to create what is known as spark jitter: the spark is formed in different places between the center and ground electrode. Spark jitter makes it difficult to precisely ignite the fuel mixture for combustion. A fine wire iridium spark plug attempts to reduce spark jitter by ensuring the spark is consistently created at the same point, allowing automotive manufacturers to reduce jitter and increase combustion stability.
Pulstar Pulse plugs have a capacitor that produces a 5,000,000 watt pulse to pre-sensitize fuel mixture for combustion and produce a spark channel 10x larger than conventional plugs. The bigger spark, coupled with the ability to pre-sensitize the fuel mixture, ensures precise combustion no matter the size of the electrode. This allows most Pulstar with PlasmaCore plugs to take advantage of a larger electrode; extending its life by slowing electrode ware to preserve your spark gap.
How can horsepower, torque, and MPG be improved while reducing emissions? By burning more of the air-fuel mixture during the time allotted by the power stroke.
The ability of Pulstar with PlasmaCore pulse plugs to sensitize the air-fuel mixture prior to the spark ensures immediate ignition followed by combustion upon spark creation and an overall faster burn rate. Testing conducted at two well-known independent third-party labs prove that Pulstar pulse plugs burn the fuel mixture at a significantly accelerated rate when compared to the premium iridium fine-wire plugs of the world’s top two leading spark plug manufacturers.
The spark, whether from a pulse plug or spark plug, can only impact the first 2-5% of the combustion process. This is called the 5% Mass Fractional Burn (MFB). In independent third-party testing, Pulstar with PlasmaCore pulse plug’s 5% MFB was measured against the leading brand’s premium iridium spark plug in a quiescent cylinder. The flame kernel area growth measured by pixels shows the flame growth at 500 microseconds (0.5 milliseconds) for the Pulstar with PlasmaCore pulse plug at 200 pixels while the premium iridium spark plug is only about 50 pixels. At 2,750 microseconds (2.75 milliseconds), the Pulstar flame kernel comprises 600 pixels compared to the iridium spark plugs 90. At 0.5 milliseconds the Pulstar with PlasmaCore pulse plug’s flame kernel is 4 times the size of the leading brand’s premium iridium spark plug; and its burn rate is accelerated, increasing to 6.7 times larger at 2.75 milliseconds.
These results not only reflect the pulse plug’s capacity to burn more of the fuel quickly; they also show its ability to ignite a lean 18:1 air-fuel mixture and burn it at an accelerated rate – improving MPG.
Additional tests conducted at the same independent third-party lab compares the flame propagation rate of the Pulstar with PlasmaCore pulse plug to a different leading brand’s premium iridium spark plug. Again, the flame propagation rate of the Pulstar pulse plug is significantly faster at 63%. The below pictures show the Pulstar flame kernel is clearly larger at 13,707 microseconds (0.013 milliseconds) and 33,187 microseconds (0.033 milliseconds) than the leading brand’s premium fine-wire iridium spark plug.
Finally, thermodynamic testing filmed at 64,000 frames per second captured the Pulstar® plasma-forming pulse and its accelerated flame-front. This high-speed video captured by AVL, the world's largest independent company for the development of powertrain systems with internal combustion engines, shows the pulse followed by the plasma sensitized fuel mixture burning at twice the rate of the leading brand’s premium iridium spark plug.