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Enerpulse explains mechanism by which pulsed energy ignition plugs enhance fuel economy

Enerpulse Technologies said that it has further identified the underlying mechanism by which its its pulsed energy ignition technology improves fuel economy, reduces emission and delivers higher torque in spark ignited (SI) internal combustion (IC) engines. (Earlier post.) Nano-Plasma Assisted Combustion (n-PAC is the process by which the air-fuel mixture in the combustion chamber is made highly reactive by an energy-dense plasma field prior to spark creation; this results in more precise combustion ignition (PCI) and a faster propagating flame front.

Linking the 5,000,000 watt nano-pulse delivered by Enerpulse’s n-PAC ignition device to the underlying of plasma physics in the combustion process is a breakthrough in understanding how our technology works and its underlying science. Unlike conventional spark plugs that only ionize fuel in the spark gap, n-PAC’s high-energy electrical discharge, which includes ionic wind and photon energy, projects well into the cylinder, ionizing a significantly larger amount of the total fuel charge.

—Wes Helgeson, senior research engineer

Enerpulse says that its n-PAC technology is the first practical and cost-effective method of capturing the well-known benefits of plasma to create consistent, faster and more efficient combustion in SIIC engines, even with lean air-fuel ratios.

Its integrated parallel capacitor circuit stores energy during the ignition ionization phase and, in a nano-second pulse, automatically discharges 1,000 times the power of conventional spark plugs just prior to the spark event. n-PAC technology is currently packaged inside the physical envelope of a conventional spark plug, making adoption easy for current and future SIIC engine applications.

In a paper to be presented at the 2014 SAE Powertrain, Fuels & Lubricants meeting in October this year, a team from Enerpulse, Texas A&M and AVL suggest that pulsed energy ignition technology may improve the limits of advanced ignition timing and leaned mixture for low-load catalyst warming. The study showed that the pulsed energy ignition technology can increase exhaust heat flux for similar combustion stability criterion (less than 15% IMEP-COV) with marginal penalty in fuel consumption and nitrogen oxides emissions, and noticeable decrease in unburned hydrocarbon emissions when compared to conventional spark plug technology.

Enerpulse provides its products to the automotive/powersports aftermarket and NatGas stationary engine service market under the brand name Pulstar. It also provides products to engine converters for vehicular NatGas fueled SIIC engines (NG, CNG, LNG, LPG, and Bio-Gas) and is working directly with several automotive OEMs in pursuit of gasoline engine platform adoption.

Enerpulse also recently announced an agreement with MAE Corporation to assist the company in securing business with automakers and Tier 1 automotive suppliers in Japan. MAE Corporation is represented by its president Toshi Goto who will serve as a business development partner and introduce n-PAC technology to senior Japanese automotive executives.

The company has sold more than one million Pulstar spark plugs into the automotive and power sports aftermarket.


  • Timothy J. Jacobs, Louis Camilli and Matthias Neubauer (2014) “Improvements in Catalyst Warming Time through the use of Pulsed Energy Spark Plug,” SAE 2014-01-2626



As someone who codes microprocessors in real time apps and has spent a couple of years studying thermodynamics bringing these two disciplines together is quite interesting.

On the electronic side, as a real life example, Chrysler 4 cylinder engines use a set of crankshaft negative-going strobe pulses with intervals at 69,49,29 and 9 degrees before TDC for each pair of cylinders. 1&4 or 2&3 resp. That way the piston velocity can be accurately computed using input compare registers to time stamp these pulses. This enables the second operation which takes a previously computed ignition point (in degrees) and loads it as a time value into the output compare register such that when this value compares to an incremental 16 bit free running counter the output pin on the chip will change state and activate the igniter.

Those not in the business may be unaware that this can be done with half a microsecond accuracy without any regard to processor latency. This is in sharp comparison to the timing variability exhibited by old style switch contacts on a distributor shaft with a degree of wobbility. However....

The elephant in the room is that the mere firing of the igniter at precisely the right time has very little to do with accuracy of the ignition of the fuel. The flame wave front as the fuel burns is less predictable in time. It follows a bell curve type distribution so it is difficult to get a perfectly running engine at slow speeds, despite the timing being crystal locked to the rotation of the crankshaft as I described.

In the past solutions have entailed the fitting of dual spark plugs or more complex firing patterns of several pulses. The industry seems more motivated, now that the hybrid premium is being gradually whittled away, to get the efficiency of non-hybrids raised.

A spark that is 1000 times should do it ! With that sort of energy I am thankful that it is accomplished within the body of the plug


how do you get a plasma before the spark ?

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