A look into the of GM’s future of engines and transmissions
GM Powertrain Europe’s comprehensive Tech Show provides answers about how cars will be propelled in the future. As part of the global GM Powertrain organization, GM Powertrain Europe has global responsibility for small diesel engines, diesel control systems, small gasoline engines and manual transmissions. Its footprint encompasses 15 facilities in 7 European countries, employing 9,000 people and producing on average more than 17,000 engines and transmissions per day.
“The top strategic priority of all development activities is to increase fuel efficiency, reduce the CO2 emissions and emphasize energy diversity“, said Mike Arcamone, Vice President GM Powertrain Europe.
The GM Powertrain Tech Show also illustrates the worldwide network within General Motors. GM Powertrain is the global leader in producing engines and transmissions, with 86 plants and development facilities in 17 countries on all continents. More than 48,000 employees develop and build 33,000 transmissions and 37,000 engines on average every day. Customers include all GM brands as well as a list of other manufacturers.
Diesel engines: Debut of the closed loop combustion process
GM has been working for 20 years on controlling diesel combustion in a closed cycle. It is also a success story for GM – concentrating on optimizing the processes inside the motor itself and thereby avoiding expansive after treatment systems wherever possible. A major breakthrough in this field is the closed loop combustion process: A sensor in the combustion chamber measures the pressure conditions in real time, and the measurements are integrated into the control system for the injection. This closed-loop process will make its market debut in 2009 in a V6 diesel that will provide 184 kW/250 hp and 550 Nm max. torque. Use of the closed loop process will not remain limited to the new V6 diesel, GM Powertrain Europe is working on a new diesel generation that will feature common technology and remarkable efficiency.
Gasoline engines: Direct injection, Turbo-charging, new HCCI process
By introducing the ECOTEC-Motor 2.2 direct in 2003 in the Opel Vectra, GM was among the leaders in bringing direct injection technology with homogenous mixture to market. A significant next step in this leading technology was the combination with camshaft phasing and turbo charging made available in the Opel GT. Its two-liter ECOTEC engine offers a remarkable peak power of 194 kW/264 hp.
Based on this technology, GM sees a major opportunity to reduce engine displacement, retain at least the same drivability and vehicle dynamics, and significantly lower gasoline consumption. This strategy, called right sizing, is particularly effective when driving under partial load.
Future developments include Homogenous Charge Compression Ignition (HCCI). Through controlled auto-ignition – as with diesel fuel – the gasoline/air mixture is burned more efficient. With the HCCI process, consumption declines by around 15 percent – with favorable emission data. To control the auto-ignition, pressure sensors are needed in the cylinders.
Transmissions: Intelligent all-wheel drive, more speeds, higher efficiency
More speeds, wider ratios, less friction losses: These are the development goals for both manual and automatic transmissions. At the same time, cars will be more fun to drive. An outstanding example is the new all-wheel-drive system XWD that is currently launched on the market in the Saab 9-3 series.
The intelligent integrated system is extremely fast to react, giving the driver plenty of feedback and reassuring security. XWD divides the power not only between the front and rear axles, but also between the two rear wheels. Optionally XWD can be combined with the electronically controlled limited slip differential (eLSD) - an electronically controlled hydraulic multiplate clutch with the effect of a locking differential. It is fully integrated into the XWD control system and in normal driving can send up to 40 percent of the torque to the wheel that has the most grip - in extreme situations even more.
GM Hybrid System: Cost efficient hybrid
The GM Hybrid System switches off the engine when the car is at a standstill. Once the foot is taken off the brake, it starts again. When coasting or breaking, energy is recovered generatively and stored in a battery. When additional performance is needed – for example in the acceleration phase – more torque becomes available.
GM favors the belt-driven Belt-Alternator-Starter (BAS). This solution is cost and package efficient because a large number of existing components can still be used. Moreover, the low inherent weight and the good packaging argue for the system. The system is most effective in urban traffic with frequent braking and accelerating, reducing fuel consumption by up to 10 percent.
2-Mode-Hybrid: Advanced full hybrid coming to Europe in Cadillac Escalade
At the heart of the 2-Mode Hybrid is an Electrically Variable Transmission (EVT). It has two integrated electric motors with an output of 60 kW each and enables driving on electric power only up to 30 mph. The sophisticated Hybrid Optimizing System also manages to recover energy by regenerative braking. Electrical energy is stored in a nickel metal hydride battery under the rear bench.
The innovative EVT with the two integrated electric motors takes up no more space than a conventional automatic transmission. The 2-Mode-Hybrid can be coupled with 2- and 4-wheel-drive and allows fuel savings for large SUVs of up to 50 percent in urban traffic. In Europe, this advanced system will first be available in the Cadillac Escalade.
E-REV and Fuel Cell: The Path to Electric Propulsion
A decisive factor in reaching greater energy diversity is the electrification of the automobile. Hybrid propulsion offers instantaneous efficiency gains. The rapid development of advanced battery technologies that use grid-fed electricity introduces the potential for a whole new range of energy sources to power the vehicles of the future. Electric drive systems powered in part by lithium-ion batteries with range extender functionalities are the consequent next step. The last step in GM’s view is the hydrogen economy, either at the power plant level or by using hydrogen in a fuel cell to produce electricity on board the automobile.
Chevrolet Volt: The first Extended Range Electric Vehicle
The Chevy Volt concept is unlike any previous EV (electric vehicle) thanks to its innovative E-Flex propulsion system. The E-Flex propulsion system consists of a lithium-ion battery and a bio fuel powered range extender. Fully charged with electricity from the grid, the Volt will have an EV range of up to 64 kilometers – enough range for most drivers to make their daily commutes gas and virtually tailpipe emission-free (fewer than 40g/km CO2). For longer drives, the Volt’s bio-fuel range-extending engine will create electricity on-board to extend the range of the vehicle to well over 700 km.
GM currently has more than 700 engineers working to bring this vehicle to market. Production timing for the Volt is dependent on the availability of advanced lithium-ion batteries that meet our safety, durability and performance requirements. GM is currently testing two different battery solutions in labs and in engineering mule vehicles on our Milford Proving Ground test tracks near Detroit.
HydroGen4 with fuel cell propulsion: On the road to “zero emissions”
For decades GM has researched fuel cell propulsion where electrical power is generated on board from hydrogen. The essence of the development so far is the fourth generation fuel cell vehicle HydroGen4. Considerable progress has been made in roadworthiness, dynamics and system durability compared with its predecessor, the HydroGen3. GM will build more than 100 units of the HydroGen4 and place them with customers as part of a global deployment plan to get comprehensive insight into the customer experience with a hydrogen powered fuel cell vehicle. Ten vehicles out of this global fleet will be running in Berlin as part of the Clean Energy Partnership (CEP) demonstration project.
HydroGen4’s fuel cell stack consists of 440 cells arranged in series. With the 73 kW (100 hp) synchronous electric motor, acceleration from 0 to 100 km/h in around 12 seconds and a top speed of 160 km/h are possible. The 4.2 kg of compressed gaseous hydrogen allow a range of up to 320 km.
Alternative Fuels: Bio-Ethanol
Bioethanol is a renewable alternative to fossil fuels and offers a CO2 advantage over gasoline of up to 70 percent on a well to wheels basis, depending on how the fuel is produced. E85 is a fuel mixture consisting of 85 percent ethanol and 15 percent gasoline.
In evaluating the environmental impact of biofuels, both the source and the method of processing are decisive. Many companies are developing next-generation biofuels, which are produced from a variety of sources including agricultural and municipal waste.