In light of rising petrol prices, stricter emission standards and the fear of the underpowered motors that often result, GM will apply a frugal, yet punchy little engine to a range of its most popular models.
According to GM’s European arm, a downsized direct injection 1,4 turbo will be offered on the Astra, Corsa, Zafira and Insignia by 2010. This unit develops between 90 and 104 kW, and is claimed to provide the performance of a 1,8-litre engine with a 10 per cent fuel economy improvement.
GM points to a combination of direct fuel injection into the combustion chambers, turbocharging, lower overall engine weight, variable cam timing of both inlet and exhaust valves and reduced internal friction as contributing to a balance between sprightly performance and good economy.
According to , who recently tested the Astra variant equipped with the 1,4-litre unit, this engine develops its peak torque at just 1 850r/min, showed great refinement and good throttle response.
GM are also in the process of developing an HCCI (Homogeneous Charge Compression Ignition). According to Uwe Grebe, executive director of GM’s powertrain advanced engineering division, the company does not yet have a specific timetable for rolling out an HCCI engine. The application of prototype units to a pair of stateside models last year, and Vectra this year, suggest that such powerplants should be in circulation between 2010 and 2015.
HCCI engines have several features that aid efficiency. They don’t utilise spark plugs inside the combustion chamber under normal driving conditions, since the fuel is ignited by pressure. Spark ignition is only utilised when the engine is cold or under a heavy load. This burns all the fuel inside the chamber completely, which lowers emissions and potentially eliminates the need for extensive pollution controls. According to Grebe, the low-temperature, flameless energy release in the combustion chamber also means the engine uses less fuel than a conventional petrol powerplant.
When HCCI is combined with advanced technologies, such as the aforementioned direct injection, electronic cam phasing, variable valve lift, and cylinder pressure sensing, it can provide fuel savings of up to 15 percent.
According to Mercedes-Benz is also developing an HCCI under its DiesOtto project, whilst VW are shying away from such technology due to a perceived requirement for expensive synthetic additives needed to make such technology viable for everyday use. So, it’s good to see that GM is adopting both smaller displacement and new technologies in their attempt to pare down our petrol bills.
Will these units come to South Africa? It’s too early to make any speculations regarding the HCCI units, but a spokesperson from GMSA has pointed out that low displacement turbocharged engines are the way that the likes of Opel and Volkswagen are moving. Confirmation is yet to be received, but the signs are good.
