More Efficient Lower Emissions Engines

Submitted 8 years ago

Current IC engines are inefficient and emit moreCO2&NOx than necessary; and can be redesigned to greatly increase their efficiency while also reducing pollution, e.g., half the fuel, half the CO2 and one-quarter the NOx required to perform the FTP cycle. My discussion below is in 3 parts: 1st larger piston diameter to stroke ratios; 2nd very substantial friction reductions and 3rd an advanced but higher risk to develop an �early bottoming cycle� engine with all helpful actions included.
1st, Larger diameter/stroke ratios with a more rapid combustion process. I propose achieving a more rapid combustion by using multiple spark plugs (or Diesel fuel injectors) per cylinder to shorten the combustion process by firing all together or better yet a firing pattern that allows increased CRs and fires each individual plug (or injector; note: it is also possible with injectors to fire all at once but control the flow rates to program the desired fuel injection rate) to maximize efficiency at each load&rpm, e.g., Four plugs/injectors make a significant gains, but 7 per cylinder 1 in the center and 6 equi-spaced on a circle at about 0.8 radius with the one in the center firing 1st near TDC gains more; and as the chamber expands firing more to increase the combustion rate allowing burn rate control as a function of crank angle; this allows increased compression/expansion ratios and with delayed initial ignition at high loads the compression/expansion ratio can be further increased. In addition to, or instead of, multiple plugs/injectors other designs can also help obtain the desired combustion rate: combustible mixture (air/fuel ratio, egr %, energy density of charge, turbocharging, compression ratio, turbulence, temperature at ignition, etc.) Another approach is to use a cam action around TDC to initially speed up the expansion from TDC and then slow it down until combustion �complete� then expand the rest of the way to BDC, either a total cam drive or normal crank drive with a cam �bump� near TDC during expansion.
2nd, friction losses should be reduced substantially; some I would consider are:
1. A substantial mechanical advantage rocker arm with an efficient rocker bearing that reduces the force on the Main&Crank bearings and additionally greatly reduces piston side load (requires redesigned piston to minimize piston viscous friction) � see abandoned US patent 5,398,652.
2. Variable oil temperature to journal bearings, e.g., split the oil flow into paths and one path is as today and another that is heated (lowers viscosity) and modulate (or a �bang bang� �simpler but not as effective) the flow from each to achieve the desired temperature, hence viscosity, oil to the bearings to minimize viscous friction losses as a function of rpm&load. Would also benefit both cold weather and startup efficiency.
3. Segmented journals: at low rpm (including lower Idle fpm/rpms) high force, oil to all segments; at higher rpms and/or low force, oil to some segments and air (or neither air or oil) to others. E.G, visualize a 1 inch journal hub be replaced by a 1.25 inch hub with 2 1/8th inch slits that in effect becomes three 1/3rd of an inch bearings that are all feed oil at low rpm high load and only some at high rpms and/or low loads.
4. Lower max pressure at high loads: 1. spring overload store and return energy to limit peak pressure, 2. with turbocharger less or no turbocharging at low rpm and gradually increase t/c as rpms increase and journal carrying capacity increases, 3 lower low rpm charge energy at high loads and restore as rpms increase (lean mixture, reduced pressure charge, increased egr, delayed ignition).
5. Use roller bearings whose friction varies little as rpms increase in place of journals where friction loss increases almost directly with rpm.
6. Lower ring friction with more balanced pressure (abandoned patent 5,271,315) and different materials&surfaces, e.g., BMW Nano Slide, to reduce friction, vary the ring forces acting on it as a function of expected chamber pressure; even consider a slight chamber wall taper to reduce ring tension as piston withdraws or relieving ring compression pressure at various cycle times or less compression force and more cylinder pressure force. Lower friction surfaces can also be used other places in the engine and in the accessories.
3rd, A multi piston expansion design, i.e., early combustion chamber exhaust valve opening (I generally model at 130 degrees after TDC) bottoming cycle described in abandoned US patent 4,860,701 except I believe the valving described in the patent is complex and I would design it with more conventional poppet valving, i.e., visualize 4 in-line cylinders: cylinder 1 is a 2 cycle compressor, cylinders 2&4 are 4 cycle combustion chambers and cylinder 3 is a 2 cycle bottoming chamber; chambers 1&3 alternate in charging and accepting high pressure exhaust from cylinders 2&4.
My recommended plan would be to incorporate with the above more efficient ICEs with Ref. 2 EPA tables 1.2-15,-16,-18,-19 with weight reductions technologies, no ethanol for fuel purposes, no EVs, very efficient cabin climate control, improved traffic controls, lean mixtures; i.e., all ICEs supplemented by well supported technologies (Mid � my label): such as fewer combustion cylinders with larger diameter to stroke engines with multi plugs per cylinder ( 4 would do � 30% reduction in combustion time; but I like 6 � 50% reduction plugs reasonably equi-spaced with 1 in the center that fires 1st near TDC or 7 plugs (or Diesel injectors) per cylinder, each plug or injector individually timed to optimize efficiency and minimize CO2&NOx, i.e., near TDC at higher than current engine�s CR/ER, ignite 1 plug then progressively ignite more plugs to increase combustion rate such that complete combustion occurs at an early crank angle) and ( Max � my label): develop and refine/optimize all technologies (including polished chamber surfaces, faster expansion after combustion with cam operation and others) for later incorporation, longer development time and higher risk, but need to be pursued.