Our first block has been poured at the foundry – ACTech in Freiberg, Germany. I was tempted to title this post as, “It LIVES!” We have been working on computer models of this complicated part for so long, to finally see a photograph of a real block made of compacted graphite iron instead of 1’s and 0’s is very very exciting.
MkII Clarke-Brayton Engine block just after being poured at the foundry
The block is now being prepared for machining, after which it will look much sleeker! The bulk of our smaller parts are already out for quote and we anticipate beginning testing on August 1st. Maybe I will save the, “It LIVES!” post title for when the engine is actually breathing.
Happy Memorial Day, everybody!
I have been woefully absent from these pages the last several months since we started the design effort on the new engine. I am excited to finally be able to share what the team has been working on so dilligently. The MkII Clarke-Brayton Engine is the next step in dramatically reducing fuel consumption in trucks, automobiles and generators without increasing costs. It is also the next step in developing a highly efficient compression-ignition 100% natural gas engine that can meet the up-coming greenhouse gas emissions regulations. This is a boxer configuration split-cycle engine implementing what we have come to call the Clarke-Brayton cycle. The thermodynamics of this engine are virtually identical to our previous “CCI” design but are implemented in a much more conventional way. Everything that we published in our SAE paper at the 2013 World Congress holds true for this engine, but many of the difficulties related to the old engine are resolved.
MkII Clarke-Brayton Engine
Section of the MkII engine
As with the previous design, in the MkII air moves sequentially through three cylinders, starting at the mid-sized cylinders at the top of the section image. This architecture allows us to achieve a 56:1 compression ratio leading to a 30MPa peak pressure. It has far less surface area for heat loss than a comparable conventional diesel due to the very small bore of the combustion chamber. The small combustion piston area leads to lower forces on the crank than a conventional engine would have if it were able to reach similar pressures, reducing rod bearing friction compared to conventional architectures. A lack of net forces on the main bearings due to the opposing forces of the piston pairs reduces main bearing friction compared to conventional engines. It expands exhaust gasses all the way to ambient pressure before the exhaust stroke. Gas transfer from one cylinder to the next is begun at equal pressures on either side of the valve, which keeps velocities low, minimizing pumping losses and eliminates blow-down. The power is produced in almost a 50-50 split between the combustion (central) and exhaust (largest) pistons. There is a power stroke every revolution. All valves are actuated by overhead cams. Piston ring sealing is completely conventional, eliminating the dynamic effects of the old design and greatly reducing the reciprocating mass.
The major components of the MkII Clarke-Brayton Engine have already been released to the foundry for casting and everything else should be released for fabrication within a couple of weeks. We will test this summer at a globally renowned engine development lab and I hope to have results to share shortly after that.
A team of just three people designed the MkII from a back-of-the-napkin idea to a fully developed test engine in 7 months. Azra Horowitz and John Clarke have both put in herculean efforts to get this done in time despite a couple unexpected thorny technical challenges along the way. I could not be more proud to be working with them.
We do not focus much on PR around here (yet), but an article was just published in Babson Magazine that features us called, “Risky Business with a Purpose”. It was a real pleasure speaking with Donna about Motiv and kinda fun doing the photo shoot out in Brooklyn with people stopping and staring wondering if I’m someone famous. Sorry for the disappointment, people!
In light of the supreme court ruling today, an idea occurred to me on a way companies can lower their healthcare costs. Things that many companies do cause many to have negative gut reactions (pun intended) such as suggesting they go on weight-watchers, and some practices that may seem discriminatory. How about paying for entry fees to competitive sporting events such as running races, triathlons, bike races, etc? This would at first really excite those who already compete, and get others interested in taking advantage of this unusual benefit. Then, people who might never have thought of training for and entering a running race will be lacing up a pair of trainers. Pretty soon I bet you would have an athletic, healthy culture building within your company. Not only would you lower your healthcare costs, you would improve employee morale, loyalty, productivity and just have more fun overall.
Being an engineer and a gear-head, I love motor racing. And there is no better combination between engineering, racing and just plain cool factor than the 24 Hours of Le Mans. You have incredibly diverse and fast cars racing on a crowded track continuously for 24 hours with two drivers hot-seating. What better way is there for an engineer to demonstrate the performance and reliability of his/her creation? It’s also a race where fuel efficiency counts for a lot. Audi took advantage of these characteristics when they decided to enter a diesel race car in the 2006 Le Mans series, taking checkered flags in the 12 Hours of Sebring and the 24 Hours of Le Mans. Diesels have been dominant in the series ever since (and the popularity of Audi TDI engines has been growing globally).
The newest Audi R18 TDI Le Mans car - A car Darth Vader would be proud of.
I can’t help but think that the CCI engine would outperform even the Audi and Peugeot diesels. You can get 30% more laps out of a tank of fuel AND you will be lighter. The only thing I can think of that would not be as good from a racing perspective is that it would not be as loud, and all true racing fans love the thrill you feel in your stomach at the sound of a high-revving un-muffled racing engine.
The rules of the LMP1 category allow for low (or no) production diesel engines and I think might be the only major race category in the world where we would be able to showcase the CCI engine. Anyone out there want to help fund a CCI engine development project for a Le Mans bid?
We are very excited to attend the ARPA-E workshop on small-scale distributed generation:
Compared to low-efficiency coal plants, with high pollution, transmission losses, inflexibility and security issues, a distributed generation network featuring CCI engines burning natural gas can provide tremendous benefits to the US’s power grid, energy security, and environment. The CCI’s high compression ratio (our demonstrator is over 35 to 1 and this is NOT an upper limit), high average temperature and low rate of volumetric change around top dead center give us the ability to ignite direct injected natural gas in a compression ignition engine without having to use any kind of ignition catalyst. In fact, a CCI at 6000 rpm can complete ignition of NG in 2 degrees of crank angle, compared to 180 degrees for a conventional diesel at 2400 rpm! (6000 rpm equates to about 6m/s mean piston speed in a CCI, similar to 2400 rpm in a conventional diesel)
Microturbines are expensive and inefficient when you cannot utilize the waste heat, as would be the case in most residential applications. Sterling engines require very expensive materials for heat transfer to perform well. Fuel cells are also dependent on rare and expensive materials.
Needless to say, we’re pretty excited about this application of the CCI!
I’ve been predicting for a while now that greater adoption of cars that utilize lithium batteries will cause a huge rise in demand of the metal causing increasing costs of batteries, rather than decreasing costs as is required for mass adoption of electric and hybrid cars. It seems this is already happening and being accelerated by tariffs and trade limitations in China where most of these metals are mined. In addition to lithium, the price of neodymium – a rare earth metal that is key to the efficient permanent magnet motors in electric and hybrid cars – has quadrupled in the last year. The Wall Street Journal has an article on this story today.
I have not seen much speculation as to the motives behind China’s protectionist moves. Given the rising prominence of their automotive manufacturing industry, perhaps they see this as a way to become the only country with the ability to make affordable electric cars. Or maybe they are just being opportunistic and exploiting their position as the only source of a material used in a growing market to make more money.
Toyota claims to be close to having an induction motor that will be able to replace permanent magnet motors in these applications. If true, this would be a huge technology breakthrough. This has been a research goal of many a scientist over the years, so it is surprising that Toyota could have come up with a solution in such short order, but they are also a company that does not tend to exaggerate their technology accomplishments so I’m looking forward to seeing what they have done.
Needless to say, rising costs is the last thing hybrid and electric cars need to start taking a more meaningful share of the global auto market. But you never know, maybe this will spur more innovative thinking leading to a completely different battery technology that is an order of magnitude better than lithium.
Increasing CAFE standards are the primary tool the government uses to force automakers to increase the fuel efficiency of their vehicles in the United States, and in general I think the population believes that getting more mileage out of their car is a good thing, as long as the car is affordable, and performs comparably to what they are used to. We are not ready to accept the range limitations of all-electric vehicles priced within reach of the middle class nor cars with tiny engines that accelerate from 0-60 in 12 seconds. If we simply replaced the gasoline engines we use today with diesel engines and make no other changes, we would see an instant increase in mileage. For instance the gasoline BMW 335i gets 28mpg highway and the diesel gets 36mpg. That is not likely to happen overnight in today’s environment.
Diesel engines are starting to build a fan-base in North America with enthusiasts who have realized that they have much better fuel economy than their gasoline powered counterparts and can be a lot of fun to drive given their superior torque. But automotive diesel engines have significant hurdles to leap before they reach mass acceptance because the cost of the engine is higher, and in America, the cost of the fuel is higher, thus negating the fuel efficiency benefit.
In Europe, diesel is cheaper than gas, causing diesel cars to be much more popular than gas and this contributes greatly to the high mileage enjoyed by the European fleet. So why is there such a price disparity of diesel vs. gas in the US and Europe? It’s simple, in Europe, the taxes on diesel are lower than the taxes on gasoline.
Germany’s chart is very representative of most of Europe and it clearly show’s how tax policy incentivizes diesel engines, helping to increase the efficiency that the market demands in their country. On the other hand, look at the US chart:
It can be difficult to see here because US fuel taxes are relatively low causing the lines to overlap a lot, but US gas and diesel prices retain their relative positions before and after taxes.
So would it not be much easier to increase the efficiency of the American fleet simply by creating a fuel tax policy encouraging the purchase of significantly more efficient diesel engines? Part of the difficulty of this is that federal taxes are only a portion of the taxes on gasoline and doing this effectively would require cooperation between Washington and the states.