We ascertained the ever worst constraint which is still existent in a spark ignition engine (SIE) is the “Constant-Volume Cycle”.
During an effective combustion in an SIE, no considerable volume expansion may occur in the combustion chamber. Hence the combustion heat energy cannot get converted to mechanical work and thus it elevates the combustion temperature to a critical level. Accordingly, temperature is the culprit that restricts the engine’s compression ratio and spoils the thermal efficiency as well.
To address this problem we’ve provided a pressure responsive volume changing mechanism (or the Energy Converter or EC for short) for combustion chamber. The EC instantaneously converts a substantial portion of combustion heat to potential energy and immediate onward use it to push corresponding expansion piston down through its power stroke. The EC is a free piston and cylinder assembly having a volume variable pressure chamber within it. We adapted split 4 stroke cycle engine design which uses two separate piston-cylinder units (a compressor and a power unit) to complete a 4 stroke cycle. Split cycle engine needs fewer valves per cylinder which enables us to accommodate the EC on the cylinder head of the power unit.
The EC can be provided by the OEMs through conventional casting and machining method. No significant infrastructural alteration is required to implement this idea.
The EC enables the engine to- use substantially higher mixture compression ratio (about 14:1), induce a very fast combustion (0-95% burn occurs in 20-25 CAD) and start ignition before TDC. These results in 2 to 7.5 times higher peak combustion pressure and about 40% lower cycle temperature than existing SIEs. Hence, NOx is not an issue. Accordingly, no need of costly three way catalytic converter.
The engine accomplishes 55% thermal efficiency at regular drive conditions which delivers above 70 mpg for light duty vehicle (LDV), comply with corporate average fuel economy (CAFÉ) standard for model year (MY) 2050.
Now, the zero emission hydrogen fuel may become affordable with our solution.
In contrast to existing SIEs, best fuel efficiency comes at regular drive conditions. Engine downsizing by 40% and 23.3% rpm increase at full load requires no boosting (supercharging or turbocharging).
Downsizing creates more scope to improve passengers’ safety measures and design more aerodynamic vehicles.
Technologies those are presently being considered to meet the CAFE standard of 54.5 mpg for MY 2025, will potentially increase the system complexity and cost ($1800 increase per unit of LDV). Our system cost does not exceed the existing average SIEs.
Between now and 2050, nearly 1.2B new car will be introduced worldwide. Considering those complying with only MY2025 standard, we can save $2.16 trillion (1.2B x $1800) on production cost.
If the fuel consumption reduction plans implemented successfully, the Global Fuel Economy Initiative (GFEI) expects 33 Gt less CO2 emission between 2015 and 2050 and a total of $8 trillion saving on fuel.
With the adoption of our solution in a few years (which is simply possible), a multiplier would be needed to count the benefits.