TOWARDS BETTER EFFICIENCY FOR ECONOMICAL AND CLEANER TRANSPORTATION SOLUTIONS:

Big problems present big opportunities, and perhaps the biggest problem to face modern civilization is the question of how we retain the advances of our mechanized society without poisoning the waters and the atmosphere (aka the human effects on the environment and climate change). The climate is changing, and it seems to be in part due to human activity. The response has to be measured and effective, not based on unjustifiable wholesale conversion of our infrastructure without proper consideration.

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It is important to note that emissions reductions in the transportation sector alone cannot solve these problems, it will take progress in electricity generation, housing, industry/ manufacturing, and even agriculture.

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Introduction

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This summary will describe my engine build plan and control methods that aim to meet the US and EU emissions standards for light duty vehicles. Please realize that the detailed STTR grant application is 15 pages and contains proprietary information that I hold closely. This web page is not intended for wide distribution, nor to be accessible from the other pages on my site. This is because it is rapidly evolving and contains details that I only wish to share with potential collaborators at this time.

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As I am sure you are aware, modern petrol (gasoline to us Yanks) combustion engines suffer a degradation in thermal efficiency when operating under low load or at a sub-optimal engine speed. Once an engine is designed, there are only a few things you can do to improve its efficiency (dictated by chemistry and physics). One of the most effective changes is to increase the compression ratio (or its companion, expansion ratio), although the practical limit to avoid detonation using regular “pump gas” is about 12 to 1 in a naturally aspirated engine; higher octane fuel is expensive. Stipulating good fuel atomization, about 85% throttle opening, electronic timing controls, and good thermal management, this leaves us with a peak thermal efficiency of roughly 35% in a typical modern well-designed petrol combustion engine, although cooled EGR can increase it a bit -- it is usually only used in Diesel engines. In steady-state operation at highway speeds, thermal efficiency drops to about 20% when tuned to meet emissions regulations. Researchers are experimenting with fuel stratification and compression ignition of petrol in an effort to drive peak efficiency higher, but my direction is different. My approach focuses on eliminating this efficiency drop under low load steady-state conditions while decreasing exhaust emissions.

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Operation in the peak-efficiency domain produces too much power, so OEMs downsize the engine to compensate, usually gearing is made suboptimal to keep the throttle a bit more open at low load, but there is a lower limit, beyond which the combustion “kernel” is cooled too much by the combustion chamber walls, causing efficiency to plummet.

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The downsized engine can either be physically smaller, or some of the cylinders are deactivated under low load when relying on traditional approaches. Physically smaller engines are unexciting, so OEMs also add turbocharging. This defeats a lot of the effort of downsizing due to higher power output and the need to reduce excess combustion heat (usually accomplished by adding extra fuel that is not burned – known as running a low Lambda in fuel injection tuning), and you are left with a lighter engine with about as much power as a larger one and a smidge higher efficiency in everyday driving. Compression ignition Diesel engines have been tried (mainly in Europe) to reduce these deficiencies (they run much higher compression and don’t need the extra fuel), but it was an unmitigated environmental disaster (Diesels burn “dirty”), probably precipitating the looming failure of Volkswagen. Finally, OEMs resort to hybridization, which is not a bad option but adds expensive and heavy battery components with limited life. Battery EVs were always a non-starter (again chemistry and physics, plus consumer interest), but politicians forced them on OEMs with the effect of decimating the automotive industry (recent reports may be overstating the problem but we could be losing Dodge, Nissan, Volkswagen, a couple of upstart electric vehicle companies, and many of the rest are hard hit). Another option is 48-volt “mild hybridization”; you lose a lot of low end “oomph” but gain a little efficiency and safety.

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Hitting a Moving Target

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The Mutable Motors project proposes to reduce exhaust emissions of petrol or flex fuel combustion-engine powered cars and small trucks to meet modern emissions standards while providing good power potential to meet consumer demand. The proprietary approach began with designing a proof-of-concept naturally aspirated or turbocharged 5-liter V8 with targets of 400 HP to 1000 HP (it varied by OEM “customer”) and steady-state cruise thermal efficiency of over 30%, aiming to meet the US “Goals 2025” emissions targets. Pneumatic valve control (so called “camless” operation) led to selection of a modified Ford Mustang 3-valve V8 “donor engine”, to have 12.5 to 1 compression ratio and full control over valve operation, including early valve closing to reduce combustion temperatures under low load – 3 valves offer more options than 2 but use less compressed air than 4. Industry has taught us that compressed air is flexible and safe, but costly. I bought a used 2007 donor engine and designed a 9-speed transaxle to pair with this engine to allow better engine speed control (aiming to improve on Koenigsegg’s “LST” unit with better control over gear ratios, reduced gear count, and more compact packaging). I also purchased a C4 Corvette for the proof-of-concept vehicle. My plan includes mild hybridization to reduce fuel consumption under higher load (acceleration) via regenerative braking although a strong hybrid with a very small battery capacity might also be possible.

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Major changes were required when the EU and US lowered emissions targets in the 2020s. Although my design evolved over time, it was clear that a drastic change was needed. Of course, I had considered using a lean-burn solution, but the 1980’s Honda CVCC engine was the only example that I had experience with, and it seemed inadequate. I had already realized that I needed a paradigm shift, and direction was provided by my viewing of a Youtube recorded seminar on Formula 1 engine operation presented by Pat Symonds, Formula 1 Chief Technical Officer (CTO), and former race engineer. I already knew that F1 used turbochargers but still managed as high as 50% thermal efficiency under load. From the video I learned that they ran much higher compression (18 to 1), even with turbos, and use a highly refined pump petrol, not very much different that what you can buy. They use a combination of Atkinson-Miller timing and lean-burn/ quick-burn technology to prevent engine damage while limiting fuel consumption under high load operation (as required by the F1 technical regulations). They run a Lambda of 1.7 and use passive pre-combustion chambers with “jets” directed outward to accomplish this, although I have seen reference to a coming change to an active system and higher Lambdas. Lambda is a ratio of the mixture (by weight) of air to fuel, compared to a stoichiometric ratio of 14.7 to 1; higher Lambdas are leaner (have less fuel in the mixture). There are commercially available active pre-combustion chambers, designed as screw-in units. They consist of an inlet channel, a central spark chamber, and a few 1 to 2 mm diameter “jet” outlets to focus the flame and spread flame fronts quickly.

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This new direction led to a major revision of my design. A smaller displacement for the prototype engine is based on the same Ford Modular V8 block (with a shorter stroke, a smaller bore, and increased gaps between cylinder liners); it will now include turbocharging and active pre-combustion chambers (I call them “precombustors”, maybe I saw it somewhere), required because of the planned high EGR content and passive chambers might not clear the combustion by-products reliably. The smaller cylinder liners and a bit of block “surgery” will also allow for a cylinder offset of about 8mm, which when combined with the higher rod/stroke ratio curtesy of the newly reduced stroke adds a little efficiency (although the reduction in stroke would normally necessitate longer rods to maintain high compression, I’m going to cut down the cylinder banks instead). I have increased my planned compression ratio in conjunction with these F1 inspired techniques (Obviously not to 18:1, since they use very expensive components). To keep peak power at 500 HP without driving up inlet air temperatures via higher turbocharger pressure, peak engine speed is 9000 rpm, up from the Ford’s 6500 rpm. With pneumatic valve control and a reduced stroke, the main change to accomplish this speed increase was to increase the peak pneumatic pressure available to operate the valves (I was issued a US utility patent in 2015 on a design using dynamic variable system pressure to reduce pneumatic system power drain at low engine speeds).

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With the updated design, the expected efficiency increases to about 45%, closing in on 60 mpg in the Corvette with few new parts needed to implement the changes. Most of the operational changes can be made programmatically through the valve control, fuel, and ignition system controls and the other parts were already going to be replaced, but now with changed specs. Precombustors and the turbocharging systems are of course newly added, and resized liners, pistons and rings, with a new crankshaft due to the reduced stroke are spec’d. Although new cylinder heads will be cast, this was always the plan (and could be made available as part of a conversion “kit”); the other new change is to the operating system since the proprietary valve-train operation is completely programmable.

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Please understand that I am only scratching the surface on how my valve actuating system controls engine behavior using proprietary methods and devices under low-load operation to increase efficiency in this regime. The complex concept is actually based on a simple realization – that optimum engine operation simply requires satisfying two (apparently) mutually-exclusive conditions; then resolving that dilemma. This in turn serves the basis for all my machinations.

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Engine

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First, we should establish that current engine designs are not capable of achieving the targets; let’s start by defining  them. My original plan was to target the US “Goals 2025” emissions standards, which equated an average 54.5 mpg with specific emissions targets. Since the highest efficiency engine speeds range between 2200 rpm to 2900 rpm for most light duty vehicle engines, we’ll use the lower speed as our “base”; we want the engine to maintain a good pace (60 mph) at that engine speed, everything else is accomplished via gearing. We also have to establish a reasonable steady-state power level, for which we will rely on a “representative modern engine efficiency” as used in a Wired magazine article (25 percent thermal efficiency at 30 mpg) since this specific data seems to be closely held by manufacturers. We do not know the testing conditions, we’ll have to make an assumption: steady-state operation at about 60 mph makes the math easier and seems to be a conservative approach; matching this fuel economy under the EPA’s “mixed driving” test conditions would be harder, requiring better cruise efficiency. At 30 mpg, this translates to 2 gallons per hour of fuel; regular gasoline carries potential chemical energy equivalent to 33.65 kWh per gallon (this is based on engineeringtoolbox.com estimates for the potential chemical energy content of 12.06 kWh/kg and an average fuel density of 2.79 kg/gal). So, we’ve liberated twice that, or  67.295 kWh and Wired says we only “utilized” 25% of this or 16.82 kWh (or 22.56 hph). This will be our target steady state power output. If you think in metric, that’s 48.28 kilometers per 3.79 liters or about 7.57 liters per hour at 96.6 kph (which is 7.84 l/100 km).

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Simplifying somewhat, power varies almost linearly through much of the rpm range in a naturally aspirated engine. Using a commonly available 200 HP 4-cylinder example (the Acura ILX 2.4-liter for instance), if peak power is at 6600 rpm (not too far off, and it keeps the math simple), then at 2200 rpm it will produce roughly 200/3 hp, or 66.7 hp with the throttle wide open. Efficiency drops when you close the throttle, and in this case, we have to close it off quite a bit to limit the engine to 22.6 hp. One path OEMs follow is to reduce engine speed so that the throttle can be opened somewhat, but lower engine speed also reduces efficiency and the balance point seems to be about 1800 rpm, but this is not an optimal solution (this engine should get about 35% peak thermal efficiency, and according to Wired we are now down to about 25%, which amounts to an effective reduction in fuel economy from 42 mpg to 30 mpg – or an increase in fuel consumption from 5.6 l/100km to 7.8 l/100km). Turbocharged engines in this class will do even worse because the compression ratio has to be reduced to prevent engine damage under high loads, and this also lowers thermal efficiency. Modern powerful, larger engines usually have higher compression ratios but can suffer even greater efficiency loss under low-load operation because of higher pumping losses via throttle closure, needed to restrict power output. Cars with big V8s tend to suffer a loss of over 5 mpg in terms of fuel economy compared to smaller engines in the same car. Therefore, it seems that traditional combustion engines are not efficient enough to meet our goals, although some low power engines coupled with electric motors can at the expense of using large toxic batteries which then have to be disposed of at end-of-life; producing those promotes child labor overseas and is energy intensive. We have now estimated that 22.6 hp is our target range for efficiency boost and found that no existing high performance solutions that are socially responsible.

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Now we need to consider how we can improve efficiency under low-load steady state operation. This will decrease fuel consumption, reduce operating costs, and reduce emissions. As mentioned above, there are only a few things one can do at this point to improve the situation by modifying an existing engine, due to physics and chemistry. To maximize operating efficiency, the engine has to be run in a narrow rpm band -- usually centered at about 2500 rpm, the throttle opening increased (usually to about 85%, but my methods will support 100% throttle opening without an efficiency “hit”), the mixture leaned, ignition and valve timing optimized – including Atkinson-Miller valve timing, heat loss controlled and EGR maximized (the limit can be increased with cooling), catalytic converter temperature optimized, fuel atomization and delivery optimized and timing optimized. There is actually one more very effective modification, but engine designers will tell you that it will not work, they are not wrong – except that they are (and that’s all that I will say on that topic for now).

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The initial US “Goals 2025” emissions target has recently been lowered (especially in Europe with EURO6 and EURO7 regulations). Considering the calculated emissions for EVs, based on electricity generation emissions, a goal of less than 100 gm per km seems prudent (see Youtube video “The EV Sale Boom is Dead, Auto Expert John Cadogan”). Although I will not go into the calculations here, the projected “best” cylinder displacement is achieved with a bore of 86.2 mm and a stroke of 76.9 mm (this will be achieved using Darton MID cylinder liners designed for the Honda K24 engine), yielding 448.9 cc displacement per cylinder -- approximately 2.69 liters for the Mutable V6 (MV6) and 3.59 liters for the MV8; I will call these 2.7 liter and 3.6 liters for convenience.

Thermal efficiency will be 40% to 45% through the majority of the operating envelope. The adoption of lean-burn/ quick-burn systems will boost the peak efficiency. Unique, proprietary valve operation will lower the load at which peak efficiency will be delivered, programmable operation also allows conventional Atkinson-Miller valve timing under high load. Using the Garrett Boost calculator with a 130 degrees limit on intake manifold temperature, a boost pressure of about 16.5 psi is prescribed, assuming a 1 psi inlet pressure drop. Although the static compression ratio will be 14 to 1, EGR and early intake closing will reduce the air charge mass by up to 40%, which will reduce combustion pressure. The Lambda will be varied from 1.4 (high load) to 1,7 (low load). Maximum power in the MV8 will be designed for about 525 HP at 9000 rpm, although this requires higher boost pressure, and high engine speeds demand increased pneumatic system pressure; high speed operation will be limited to about 20 seconds accumulated over any 5-minute time span. For better durability, with standard boost pressure based on intake manifold temperature of 130 degrees (F) the peak “continuous” power rating will  be 340 HP, about the same power as the donor engine’s “native” power potential while burning half as much fuel. This is all as calculated with Garrett’s Boost advisor combined with engine simulator testing and final numbers will require prototype verification.

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This is where another plausible new method entered consideration. The decrease in bore sizing with an attendant decrease in liner diameter increases the inter-bore spacing and makes rotating the liners seem possible, and a potential efficiency gain of 10% (see rotatingliners.com) would allow me to target a 50% thermal efficiency in a 500+ HP motor, since I was already at 45%. Reaching 50% provides both a psychological impact and is competitive with many electric company power grids. The rotating drive mechanism might have to be placed at the bottom of the cylinder below the water jacket (where these engines have much more available space). An electric motor might drive the liners’ rotation at a constant speed (to be determined, but the patent holder says that about 800 rpm will be optimal), there should be room to wrap drive gears around cylinder bases within each bank, Ford’s cylinder spacing is 100 mm and the new bore diameter is 86.2 mm, the liner thickness should be safely reducible and splines machined for gear mounting at the bottom, where combustion stresses are lower; at the top gears might interfere with the (outer liner) sleeve mounting system. Lubrication and sealing has already been tested by the system developer. This is certainly an open question at this point, the patent owner has expressed willingness to support collaboration. If these devices and methods are implemented, it should be in a second proof-of-concept engine so comparisons can be made.

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Transmission

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The programming of the transmission control unit determines how the engine “behaves”. Most transmissions are programmed to reduce engine speed below its optimal-efficiency rpm to open the throttle wider and reduce engine “pumping losses” under low loads. The transaxle designed to pair with the Mutable engines is a 9-speed unit with ratios of about 79% between gears to maintain the correct rpm regime under low-load (roughly 2200 rpm to 2800 rpm, to be tested). The gears are also designed to reduce operating losses using double helical gears and modern mechatronic controls.

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The transaxle will hold the gear sets in place via 3 shafts. The input and intermediate shafts run parallel, with the input shaft aligned with the engine driveshaft and a torque tube stabilizes this alignment. The intermediate shaft will be offset to the side and up from the intermediate shaft. Spacing will be such that the output shaft end aligns to the side of the intermediate shaft so the shaft ends form a triangle, although the output shaft is angled (primarily relative to the intermediate shaft) due to the gear ratios used; this angle is easily compensated for in the output gear face angles and differential gear set face angles. Each of these shafts will hold 3 gears, meshed with each other via the intermediate gear sets. The intermediate gears will be fixed to the intermediate shaft via splines (this arrangement eliminates three gears on the intermediate shaft compared to the Koenigsegg LST). Each of the input and output gears will be driven selectively by wet clutches (similar to modern automatic transmission clutches). These six clutches allow for 9 gear ratios. An electric starter-motor-generator will be affixed to the intermediate shaft via splines and will rotate backwards in lieu of a reverse gear (all three input shaft gear clutches will be disengaged for this), reducing gear count by 2 more. Thus 9 physical gears can provide 9 driven gear ratios and reverse is handled with no additional gears. The mechanical efficiency should fall between that of manual and automatic transmissions, with very quick gear changes (almost as fast as Koenigsegg’s “Lightening Speed” transmissions).

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There will be multiple operating modes, including a manual mode using paddle shifters and a hand-operated clutch patterned after Formula 1 hand-clutch and paddle shifter operation. A mild-hybrid drive will include an electric motor-generator-starter mounted along the transaxle intermediate shaft and two electric motor-generators driving the front wheels, capable of generating battery charge in highway cruise, where hybrids normally have some difficulty charging to support engine efficiency.

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Since this C4 will include a front engine, rear transaxle design with torque tube and have a high engine redline of 9000 rpm, the constant velocity driveshaft will be attached to the engine via a torque convertor and 1:3 planetary reduction gear-set. This controls vibration and reduces stress and strain in the driveshaft end-joints. Slower rotation also aids in driveshaft retention in the event of a vehicle crash (at the expense of a slight loss of mechanical efficiency).

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Hybrid Targets

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Large batteries cannot provide motive power and simultaneously reduce vehicle emissions; despite so called “net zero” claims, hydrocarbon fuels power the production of BEV / hybrid batteries and the electricity to drive them for a near “net effect zero” on emissions over vehicle life and an increase in landfill pollution (the extra weight of the batteries also increases energy consumption and tire-wear particulate pollution). There are also social and human impacts due to the use of child labor (so called “artisan miners”) for raw material mining and the requisite quantities of raw materials will worsen scarcity. A better approach is to focus hybrid drives so that small batteries are just powerful enough to drive supplemental electrification without the expense, waste, and social costs of large batteries; battery-only endurance is a lost cause and will always be.

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Mild hybrid 48-volt batteries provide the benefits of regenerative braking and smooth a vehicle’s power load, thus reducing the net fuel consumption of an internal combustion powered vehicle while incurring only a fraction of the extra emissions from the production of large batteries. These smaller batteries are also somewhat safer, given that regulators seem unable to pass sensible safety standards for large batteries in vehicles (Youtube’s John Cadogan again, plus almost any video on the channel “StacheD Training”). The real frontier is coupling these smaller 48-volt electric supplemental systems with improved (more efficient and less polluting), yet powerful combustion engines, combined with improved fuels that may eventually supplement or replace petrol.

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The target vehicle “standard” average acceleration rate from 0 to 100 km/h (27.8 m/s) will be 1.5 m/sec2 (about 15.3% of 1 g). Assuming a mass of 1600 kg (3528 lbs), this requires an average power output of about 49 kW (66 hp) for 18 seconds to reach 100 km/h based on the “hpwizard.com” calculator results -- friction and drag factors are included in the calculator algorithm. Since drag increases exponentially with speed, the calculator predicts that the first 50 km/h (half the target speed) will be reached much more quickly (5 seconds) than the second -- from 50 km/h to 100 km/h (13 seconds) -- with a constant power output.

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To achieve a more constant acceleration for comfort, engine power can be varied by the ECU (using throttle position to control acceleration, in a unique approach to “eco mode”) to more closely even out these acceleration times (a rough calculation gives about 16 kW (21 hp) average for the first 6 seconds to get to 33 km/h, about 43 kW (58 hp) average for the second 6 seconds to get to 66 km/h, and about 75 kW (100 hp) for the third 6 seconds to reach 100 km/h). We want electric motor power to supplement the acceleration such that the split averages 2:3 electric:combustion or better on average for standard acceleration. Based on the average power output (49 kW), the calculated peak electric power of 20 kW (27 hp) at 48-volts requires 417 amps. With three 48-volt motors (one in the transaxle and one for each of the front wheels), this requires about 140 amps (6.7 kW) per motor. The market trend is towards bigger batteries for extended range, but since this application focuses on regenerative braking, power “fill” during acceleration, and for pneumatic compressor power, the battery capacity can be reduced. If less than standard acceleration power is demanded via the throttle, the reduction will be made to the internal combustion engine load first (to maximize fuel economy), until battery reserve decreases to about 20% -- at which point only engine power will provide acceleration. Higher acceleration will be provided by increasing the combustion engine output.

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In one embodiment, there will be two 48-volt batteries in parallel, possibly Toshiba SciB type to support the high energy drain rate required. The battery’s discharge rate must easily provide over 1 minute of acceleration support and remain within operating specs. One of these batteries focuses on supporting engine operation (pneumatic compressors, etc.) and the other focuses on drivetrain motor-generators-starter, but the grounds are common (for safety). The motor-generators will provide regenerative braking. On compound dual turbocharged installations, the large turbo’s turbine will power a small generator when the compressor is “ineffective”.

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Emissions

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We can easily calculate exhaust emissions: chemists tell us that burning 1 kg of petrol produces about 2,3 kg of CO2 emissions, this is fairly constant for all hydrocarbon fuels as each carbon atom in the fuel is combined with two oxygen atoms in the combustion process and hydrogen is the lightest element so contributes little mass.

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Therefore, Wired’s example engine produces an average of 13,52 kg of CO2 per 100 km [5,88 kg x 2,3 = 13,52 kg] from 5,88 kg of petrol, that’s 135 g / km. Over an equivalent driving course with a similar vehicle, the Mutable Motors MV8 engine is expected to produce 7,87 kg of CO2 [3,42 kg x 2,3 = 7,87 kg] from 3,42 kg of petrol (78,7 g / km), a reduction of about 5,65 kg of CO2 per 100 km (56,5 g / km).

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For highway cruise, an estimated 11,18 kWh per 100km [13,97 kWh x 80% = 11,18 kWh] steady-state cruise estimated “load” represents a power decrease of 20% from the given mixed driving load, which would equate to about 3,65 liters (2,74 kg) / 100 km [4,56 L x 80% = 3,65 L] (64,4 mpg) and would produce 6,3 kg of CO2 per 100 km [2,74 kg x 2,3 = 6,3 kg] from 2,74 kg of petrol (63 g / km of CO2).

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Market and Regulatory Considerations

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One of the primary regulatory drivers is (ineffective) low emissions requirements, although draconian fuel tax levies impact some areas as well – driving up the price of gasoline at the pump. Since these are driven in turn by political considerations, some regions will not be reachable for marketing (California and the UK come to mind, with their overly enthusiastic proclamation of false “net-zero” goals). On the other hand, the worldwide automotive market is ripe for an engine supplier that can provide the power consumers want with exhaust emissions rivaling electric power-plant emissions. The majority of electricity is generated by burning hydrocarbon fuel and will be for the near future. Many “futurists” predict a major change, but they have for decades with little real progress.

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Since OEMs have been slow to respond (or capitulated and depleted corporate coffers to pursue the “better battery” dream), there should be a good demand for an independent engine supplier that can provide a reliable, economical, powerful, and eco-friendly engine and drive system. This is never going to be the “Yugo” of modern car affordability. Electronic controls, complex fuel systems, turbocharger, and reliable pneumatic drivetrain systems will cost money. On the other hand, if the US “Goals 2025” lifetime fuel cost savings of $8000 USD can be realized then it makes sense from political, market, and psychological perspectives. The proposed system will accumulate engine load data through vehicle trips using built in sensors, compare with fuel consumption, and report actual efficiency (perhaps graphed over speed or time) and show comparisons to other forms of transport. The company intends to publicize this information to improve consumer awareness.

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Worldwide small vehicle sales total roughly 80 million units, although some are EVs and some are Diesel powered. Governments are feeling political pressure to reduce the impact of vehicles on the environment, but their reactionary regulations have lacked a basis in comprehension and wide perspectives. The result is false step after false step (in the EU, first Diesels and then EVs were seen as “magic bullet” solutions but just turned out to be “bullets”). It is trendy in some circles to blame high performance light duty vehicles for the problems, but consumer interest still remains. Petrol prices are high (often due to the same government desires) so consumers should respond well to an option that satisfies the regulators and provides a good, useful, fun power potential that saves money at the pump.

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Conclusion

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Our goal is to reduce the efficiency loss normally associated with economical low load steady-state operation to reduce real world fuel consumption while also minimizing exhaust emissions and controlling combustion temperatures to minimize NOx emissions using a combination of proprietary and well-known methods and techniques. The Mutable Motors approach is to vary engine operation using programmable pneumatic valve actuation to control various aspects of engine operation over multiple “modes”, some automatic and some driver selectable. Vehicle manufacturers have reduced engine size to chase this goal (to increase fuel efficiency under low demand), but have failed to make a substantial improvement in daily-driving fuel economy, modern fuel mileage is not much different than that of the Ford Model T, having dipped during the 1950s and 1960s and rebounded during the 1970s and 1980s. Efficiency increases since 1915 were mostly needed to cover the higher power modern cars and accessories require, not improve fuel economy, and improvements in the last 20 years have been minimal (and mostly due to electronic controls that allow more precise, variable control), except for some research and race engines (which still do not achieve high efficiency under low load)[1].

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It is important here to point out that engine efficiency is only one factor in fuel economy, vehicle weight and shape, and accessory loads also play key roles. It is also important to point out that using large batteries to “supplement” or even replace engine power so that a vehicle can achieve better efficiency and reduce emissions is partly achievable and partly “smoke and mirrors”; production of large batteries is terrible for the environment and the lifetime emissions reductions in use are minimal at best, the gain is distorted when viewed over short time scales and not accounting for electricity production emissions (which varies by generator type, but on average are not much lower than combustion engines are capable of using my methods, kWh for kWh). A note to those who think they’ve found an “answer” by factoring in the emissions due to fuel preparation and delivery, the same applies to electricity generation so it’s a wash.

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The engine series will include Mutable V6 and V8 (MV6 and MV8) platforms; larger engines and a straight 6 engine are also possible if demand dictates. All pistons, rings, cylinder liners, connecting rods and rod bearings, and valves (2 asymmetric intake, 1 exhaust) and electronically controlled pneumatic valve actuators will be common across the series to minimize development and supply chain costs. Compression ratios will be 14 to 1, combustion chambers and cylinders will be offset 8 mm, consistent intake and exhaust runners and cooling passages with common designs will be used, although block cylinder count and bank angle will vary. As in Formula 1 engines, early Intake valve closing will reduce peak pressure under high turbocharger boost conditions. An e-turbo may provide supplemental air injection (SAI) for cold starts to preheat catalytic converters if indicated by testing. Mild hybrid 48-volt integrated motor-generator-starter systems will be common as components of a custom designed 9-speed multi-clutch transaxle layout mounted to the intermediate shaft (unlike the Koenigsegg multi-clutch LST, only the intermediate shaft will have fixed gears, and reverse will be provided by the M-G-S). We plan a mild-hybrid drive system with 48-volt batteries to provide the supplemental power (derived through regenerative braking and e-turbo motor-generators) while avoiding most of the negative aspects of large battery production.

Peak “standard” power production for these  “anchor” engines will be about 190 kW and 255 kW (255 hp and 340 hp) for the MV6 and MV8 in 16 psi “standard-boost” operation (this is based on a limit of 130-degree peak intake manifold temperature for durability); higher turbo boost can increase these numbers, up to 395 hp and 525 hp – but the intake temperature will climb and operation at higher turbocharger flow is time-limited. Drivetrains can be built and supplied, licensed for production and/ or kits produced to retrofit older vehicles, including classic cars. At the extreme, production rights for discontinued sedan models (Dart, Lancer, Impala, MXZ,…) could be secured and vehicle production even undertaken.

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The automotive industry is in crisis, brought on by bad management decisions that were largely driven in part by misinformed political policies. The continuing attack on “car culture” will eventually kill off personal transportation as we know it. By providing an environmentally responsible alternative based on sound engineering and a love of the thrill of driving a responsive vehicle, Mutable Motors may be able to save the automobile as we know it.

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[1] For those unfamiliar with the subject, there are a very limited set of methods available to increase engine thermal efficiency: reduce friction losses (through material, component design, and lubrication improvements), reduce pumping losses (usually visualized as reducing throttle closure – contrary to popular opinion the throttle does not increase power it’s function is to reduce airflow, throttle operation reduces power and causes an efficiency loss), increase the compression (or expansion) ratio, decrease unburnt fuel (for which there are multiple avenues), operate the engine in a very narrow rpm range (faster than peak efficiency engine speed increases friction, lower increases the heat lost to the cooling system), raise temperatures of the engine components (this approach is very limited by materials and fuel properties), and optimize ignition characteristics (again, this entails many aspects). Many of these methods increase the production of NOx, and engine design is the art of manipulating the compromises as these approaches are combined, while integrating other vehicle performance targets and addressing government regulations.