Complicated can lead to disaster, or changing the game completely.
Since the internal combustion engine was conceived, there's always been a next wall to break through in technology. Concepts tend to arrive long before those breakthroughs, and engineers can only work with the technologies, tools, and money they have available at the time. A large part of engineering is simplifying or taking earlier attempts at a problem and making them more efficient. That's lead to things like fuel injection replacing carburetors and digital engine management taking over from manually setting points in a distributor.
It's also how we get from the early giant 16 cylinder engines to the complicated and flawed 16-cylinder engines of the mid and late 20th century we'll see in this list, and then to the 16-cylinder engines now powering Bugatti's fastest hypercar. Or, from early turbocharging exploits by Oldsmobile to the modern compact turbocharged units we find now in both race cars and economy driven road cars. These are the complicated solutions to issues thrown up along the way, as well as a couple of examples of how complicated just adding cylinders can actually get.
In the summer of 1952, Porsche was still a young automaker, but working hard to forge its cars in the heat of racing. Porsche had won its class at Le Mans the previous year with a 1.1-liter engine but wanted to do some real giant killing the next year. That meant just six months were available to develop a better breathing and higher revving unit in the existing packaging size of the air-cooled flat-4.
Up stepped Ernst Fuhrmann to design a 4-camshaft race engine that had canted intake and exhaust valves that required a complex arrangement of bevel gears and shafts to work properly. The finished engine required many hours and meticulous care to rebuild but was amazingly reliable at wide-open throttle for long periods while providing sharp acceleration out of corners. With cars using the engine, Porsche racked up five overall victories at the Targa Florio and a staggering 16 class wins at Le Mans. In total, it powered over 1,000 professional racing victories and over 2,000 class wins.
Oldsmobile's first turbocharged engine was a version of the 215 V8 in 1962. It used a small T5 Garrett turbocharger with an integrated wastegate. The compression ratio of 10.25:1 caused problems with the 5 psi of pressure under enthusiastic use of the throttle peddle though. Oldsmobile solved that problem by developing a complicated water-injection system to spray metered amounts of a 50:50 methyl alcohol and distilled water mixture into the intake manifold. Conveniently, Oldsmobile would also sell you a bottle of the mixture, with a little rust inhibitor added, called Turbo-Rocket Fluid.
The fluid would run out in as quickly as 250 miles and caused regular complaints of a lack of power by owners of the Oldsmobile Jetfire. They were, predictably, not topping up every couple of hundred miles with the fluid.
In the 1990s, Saab was rocking its implementation of turbocharging but the Swedish automakers still had an issue they wanted to iron out. High intake pressure needs a low compression rating from the engine to avoid knocking. In the early 2000s, Saab tried a creative approach to perfect the concept of a variable compression engine. The idea involved building a cylinder head integrated with the engine block, but the head had mechanical arms that, when actuated, tilted the assembly on a hinge by up to 4 degrees. The end result was that, under heavy throttle, the head would tilt to make more space in the combustion chamber and lower the compression ratio.
This engine was actually a 5-cylinder lump with a twin-screw supercharger attached. It could make 150 horsepower per liter of displacement, but due to the complexity needed to make the tilt happen, it never reached production in the Saab 9-5 it was destined for. However, Nissan has now picked up the mantle and made a production variable compression engine.
When you positively have to get the most out of 1.8 liters of displacement, find some Italian engineers. The Lancia ECV (Experimental Composite Vehicle) was developed to replace the Lancia Delta S4 in the 1998 season of the World Rally Championship. It developed 600 horsepower from a 1.8-liter engine using two turbochargers utilizing a valve system that crossed (with an intake and exhaust valve on each side,) to allow the turbos to be fed by two separate manifolds. A single intake took care of the intake air, hence the Triflux name. It also looked like a cool robot when photographed from a certain angle.
The idea for cylinder deactivation to balance fuel economy with performance has been around since as early as 1905 and again in 1917. The next shot at the engineering to pull it off came from Cadillac in 1981 and with the help of the Eaton Corporation. The Cadillac V-8-6-4 system was designed for the Computer Command Module to shut off either 2 or 4 cylinders depending on information received by the sensors monitoring the engine speed, idle speed, intake manifold pressure, coolant temperature, air pump, and exhaust. If the microprocessor sensed a sustained cruise, it would activate a blocker plate that physically moved the rocker arm in order to prevent the camshaft from opening the valve.
It was an extremely complicated system using late 1970's and early 1980's technology, and the software required was nowhere near fast enough and many Cadillac owners deactivated the cylinder deactivation. Mitsubishi picked up the baton, but it wasn't until 2003 that Chrysler got it right with the Multi Displacement System on the 5.7-liter Hemi V8 engine.
Volkswagen has a lot of experience when it comes to wonderful engine designs, and the W8 engine that was installed in some 2001 to 2004 Passat models is one of them. It was the precursor to the W12 configuration used for the under-appreciated VW Pheaton. The genius of the W8 came in the form of two 15-degree VR4 style engine blocks being mounted at a 72-degree angle against each other and coupled with a single crankshaft. That meant the engine package was almost a perfect square and would fit in the space a typical V6 engine would comfortably fit.
In the history of engines, British Racing Motors had reached, what they believed, the limits of the V8 in the allowed capacity for 1960's Formula 1 racing. The team started development on a 48-valve V12, and then really shot for the moon with a 16-cylinder engine arranged in an H configuration. It was a wonderfully ambitious disaster. BRM took its 1.5-liter 16-valve V8 and turned it into a flat-8, then mounted another one on top so that from the side it resembled an H. To make the H16 configuration work, each slice of the engine required its own fuel injection system, radiator, and water pump. Also adding to the weight was a complicated crankshaft assembly and a lot of engine vibration, harsh even for a race car.
The power was excellent with 400+ horsepower at 10,000 rpm, however, the power band was narrow. The engine came with other crippling issues, such as having a high center of gravity and the need for four separate exhaust systems. This would have been an interesting swing and a miss if it wasn't for the fact BRM's partner for developing the V12 hadn't bought himself out of the agreement and left them with just the H16. It was raced in a Lotus car, and British racing legend Jackie Stewart didn't have anything nice to say about the engine. He described it as "a boat anchor."
When automotive engineer Claudio Zampolli in a joint venture with music composer Giorgio Moroder decided to try and outdo Lamborghini, they went with an absurd 16-cylinder engine because 12 cylinders wouldn't grab the headlines needed. Cadillac had built a V16 way back in the day, but that was in the 1930s and wasn't dropped in the middle of a car that was expected to scream around a track as well as the road. Zampolli took two flat-plane V8 engines based on the Lamborghini Urraco P300 engine and custom fabricated a single aluminum block cast by a specialist in Modena, Italy to build the monstrosity.
Bugatti finally perfected the 16-cylinder engine, and the cost of a Chiron speaks to just how complex an engine it is to run reliably and how much power it produces. While it does, upon casual observation, look like a bunch of VW engines welded together, it's also a 64-valve, quad-turbocharged, lump of exquisitely engineered craziness. It uses VW's VR system of staggered cylinders developed to avoid the weight of a V6 configuration, except the W16 uses two banks of 8 cylinders set at 90 degrees. The beauty is that it allows two overhead camshafts to be used to drive each set of banks, making four used in total. To get an idea of how complex the W16 is, the firing order goes: 1-14-9-4-7-12-15-6-13-8-3-16-11-2-5-10.
Cylinder deactivation and variable compression engines are now out in the real world. What's currently being developed is a system that allows valve lift, timing, and duration to be independently controlled by engine management software. The mechanical link between the crankshaft and valve operation has been a factor for all piston based engines since the beginning and it's the last analog system in an engine. Camcon Automotive in the UK, with Jaguar's help, has developed the concept and the system is currently being offered to major automakers.
It uses a system of electromechanical actuators that drives short camshafts that open a valve or a pair of valves each. In the experimental engines, there are eight camshafts and actuators running the length of the engine. That means each individual valve can be controlled exactly by the ECU and adapt to the driver for efficiency when at low speed, cruising at any speed, or delivering as much power as possible when opening the taps.
Road trials to prove IVA's real-world reliability and, when mixed with cylinder deactivation, could be as important to engine development as fuel injection taking over from carburetors. Or, it could be too complicated to be reliable yet and we should just reset and welcome our electric motor overlords now.