A review of parallel and series turbocharging for the diesel engine

Abstract

Several turbocharger units can be used for engine boosting in series or parallel arrangements in which they are phased in and out according to the operating conditions of the engine. This technology has the potential to facilitate downsizing of automotive engines in order to yield benefits in terms of their transient performance, the fuel consumption and emissions output. This review investigates the benefits and drawbacks of series and parallel turbocharging arrangements. Since the effectiveness of using the boosting technology crucially depends on the control scheme applied, developments in the modelling and control approaches used in single-stage, series and parallel turbocharging are also examined. In comparison with single-stage turbocharging, using several turbochargers in series or parallel can provide a faster transient response without compromising the fuel consumption, while also having the potential to provide higher boost pressures. Novel non-linear and robust control approaches have demonstrated improvements in performance and robustness over traditional approaches used in commercial engine control relying on separate control loops for the different engine variables.

Review of Some Methods for Improving Transient Response in Automotive Diesel Engines through Various Turbocharging Configurations

“…The first is the control system (see, for example, a simplified version in Figure 6) essential in automotive applications due to the highly changing operating conditions (e.g., "regulated" two-stage turbocharging). For example, the HP unit might be by-passed at high speeds and loads to avoid overboosting (Hiereth and Prenninger, 2007;Canova et al, 2009;Zhang et al, 2013). The second is the matching between engine and turbochargers, which is obviously a more difficult task compared to single-stage units, as the second turbocharger induces one more degree of complexity (Watel et al, 2010).…”

Experimental evaluation of Turbo-Matching of B60j67, B60j68 and A58n75 Turbochargers by Data-logger Method

“…Though the advancements in system design like the variable geometry turbine, common rail injection system, and multiple injections, the problem has still persisted due to the limiting parameter say the supply of air. [19] Discussed in detail about the benefits, limitations of turbo charger in single stage, parallel and series arrangements. According to the literature the turbocharger matching is a tedious job and demands enormous skill.…”

“…It is because of the availability of a very low pressure ratio after every stage than single stage [21]. Some cases the turbocharger characteristics are not readily available, and in some cases, not reliable or influenced by the engine which is to be matched [19]. Nowadays the Simulator is used for matching the turbocharger to the desired engine.…”

Experimental Study on Turbo-Matching of Turbo-Charger B60j68 for Commercial Vehicle Engine

“…Though the advancements in system design like variable geometry turbine, common rail injection system, and multiple injections, the problem is still persist due to the limiting parameter say supply of air. [19] discussed in detail about the benefits, limitations of turbo charger in single stage, parallel and series arrangements. According to the literature the turbocharger matching is a monotonous job and demands enormous skill.…”

“…It is because of the availability of a very low pressure ratio after every stage than single stage [21]. Some cases the turbocharger characteristics are not readily available, and in some cases, not reliable or influenced by the engine which is to be matched [19]. Nowadays the Simulator is used for matching the turbocharger to the desired engine.…”