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News and Library > Latest features > ultimate boosting solution > applications > ultimate boosting solution - applicationsgasoline downsizingIt is well established that by reducing engine capacity and speed, substantial benefits in cycle CO2 emissions can be gained. The percentage improvement gained is strongly related to the average cycle load with lightly loaded cycles giving the greatest improvements. Figure 1 shows simulated results for a “C” class vehicle on the NEDC cycle.
Figure 1 - Cycle CO2 predictions In order to be acceptable to the customer the output of the downsized engine must be augmented to produce acceptable performance. Turbocharging is the dominant boosting technology but the transient and low-speed performance of such systems limits the acceptable downsizing ratio to around 1.4. Furthermore turbocharged engines do not realise the full theoretical CO2 savings as the same issues impact on vehicle gearing and gear selection. Our SuperGen system enables a downsizing ratio of 1.6 with no compromise to response whereas the TSG system allows downsizing ratios of up to 2.5 also without compromise to driving behaviour.
Figure 2 - Turbo-SuperGen system EUV and US light dieselGreatly increased EGR rates are, for many OE manufacturers, a key part of their strategy to meet EUV and US emission standards. The TSG system combines the SuperGen unit with a conventional variable turbine turbocharger. This provides major improvements in range and control of EGR and greatly reduces particulates during rapid accelerations. Furthermore the TSG eliminates poor pull-away and low speed driving behaviour whilst simultaneously enabling a 50% increase in specific power output.
Figure 3: Diesel Turbo-SuperGen application comparison H2 ICE and HCCIBoosted lean combustion is attractive from efficiency and emissions perspective. However the available exhaust gas energy is marginal under many driving scenarios making an unassisted turbocharger impractical. SuperGen can be employed as a primary boosting system or it can be combined with a turbocharger (TSG) for ultimate efficiency and output.
Figure 4 - NOx emissions for H2 Engine Heavy and off-road dieselThe TSG system offers large improvements to speed range, rapid particulate free transient response and greatly enhanced EGR capability. Furthermore the system enables the turbocharger to be optimised for best fuel consumption. TSG also provides a solution for diesel engines coupled to rapidly changing loads (e.g. agricultural / industrial applications) providing major improvements to control dynamics whilst maintaining combustion conditions for low NOx and particulate emissions. Transient performance is greatly superior to turbocharged engines even in twin-sequential form - see Key Advantages i-hybridConventional hybrid technology delivers CO2 reduction though 4 main mechanisms.
For most usage patterns the largest potential benefit is from the first of these. In order to maximise the effect however whilst providing consistent and dependable performance requires a large amount of energy storage and high continuous ratings for power electronics and electrical machines. This of course drives high system costs. The i-hybrid approach combines the advantages of hybridisation and boosting to deliver hybrid benefits within a self-sustaining system and with much lower electrical power and storage requirements.
Fig 5 - i-hybrid operating modes
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