#CylinderDeactivation

We return to the saga of GM’s High Technology engine today, after taking a diesel detour in our last entry. Concurrent in the High Technology engine’s timeline, the Oldsmobile diesel’s failure was quick, but certainly not painless. It put the majority of American consumers off the idea of a passenger car equipped with a diesel engine. And by the time GM pulled the diesel from its various brand lineups, there was a strategy change over in HT4100 land: Not calling the engine HT anymore.

In today’s edition of Abandoned History, we return once more to the late Seventies engines of General Motors. After the disaster which was the V8-6-4 and the subsequent release of the quite flawed HT4100 V8, we take a sidestep today into diesel. Time for a turn with the cost-cut cast iron Oldsmobile oil burner that accompanied the troubled gasoline engines at GM dealerships across the country.

In our last edition of Abandoned History, we covered the years leading up to the release of the Cadillac High Technology V8. Used almost exclusively in 1981, the disastrous V8-6-4 had a primitive engine management system that could deactivate either two or four cylinders on Cadillac’s traditional V8. And while the idea was sound, the technology and engineering behind it were not. Cadillac was left in a bind and needed a replacement engine immediately. But the engine of choice was not finished, and not ready for primetime. Ladies and gentlemen, welcome the medium-rare HT4100.

A modern and efficient V8 of 4.1 liters, the HT4100 was the exciting way forward for Cadillac’s propulsion needs in the early Eighties. The engine came hot on the tail of a very iffy cylinder deactivation experiment, V8-6-4. Unfortunately, just like the cylinder games before and the Northstar after, the HT was plagued with issues that took years to iron out. The HT in its name meant High Technology but could’ve meant Halfway There. Let’s travel back to the Seventies and talk cylinders.

Despite the switch to low-sulfur fuel and ever more stringent emissions regulations around the world, compression ignition technology still gets a bad rap, tarnishing the remaining crop of diesel engine offerings despite their fuel economy advantages.

In the world of heavy duty pickups and large commercial vehicles, it’s a case of diesel or what else? Electric motors powered by battery banks the size of a refrigerator warehouse? Gotta use what works.

Diesel engine maker Cummins sees plenty of life left in the technology, and believes better is possible. If gasoline engines can shut down cylinders at will to conserve fuel, why not oil burners?

Sales of midsize trucks are heating up, and General Motors doesn’t want its slice of the pie to grow stale.

Changes are coming to the 2017 Chevrolet Colorado by way a host of powertrain updates aimed at squeezing better performance and fuel economy out of its volume model.

General Motors may use an advanced cylinder deactivation technology, co-developed with Delphi and Silicon Valley startup Tula Technologies, in its SUVs and V-8 cars to shut down up to six cylinders to maximize fuel economy, Automotive News reported.

According to the automaker, GM in 2012 invested in Tula, which specializes in automotive engineering. The automaker announced in January that it would pursue the advanced cylinder deactivation technology for some of its SUVs, which could improve fuel economy by 15 percent in cars with engines with more than four cylinders.

The system, dubbed Dynamic Skip Fire, keeps the throttle open during operation and controls cylinder firing through a special valve that cuts off oil to the deactivated cylinders’ valve lifters. According to the company, the engine computer changes the deactivated cylinders to avoid vibration or noise.

General Motors has played with cylinder deactivation technology since the days of Carter, sometimes successful, sometimes with more disastrous results.

With Tula Technology’s Dynamic Skip Fire, GM is banking on the former.

Though full electrification might not be in the cards for most consumers, those looking for turbo power for their vehicles could find a little bit of that black magic in the turbo itself down the road.

Cylinder deactivation is available on a handful of Chrysler and General Motors V8s, as well as Honda V6s, cutting power to a set of cylinders in order to boost efficiency in the short-term. However, one supplier wants to take this further by using the technology on turbocharged three-cylinder motors, deactivating one cylinder while the other two do all of the work.

Another day, another early unveiling prior to the 2014 Detroit Auto Show, this time from Volkswagen AG with their 42-mpg Passat BlueMotion Concept.