Comparison of Turbocharging and Pressure Wave Supercharging of a Natural Gas Engine for Light Commercial Trucks and Vans

Abstract

To increase the efficiency of a natural gas engine, the use of a Miller camshaft was analysed. To avoid a decline in the low-end torque and also in the transient response, a pressure wave supercharger (ComprexTM) was compared to the conventional single-stage turbocharger. The analyses for this conceptual comparison were performed experimentally, and the data were then used to run simulations of driving cycles for light commercial vehicles. A torque increase of 49% resulted at 1250 rpm when the ComprexTM was used in combination with a Miller camshaft. Despite the Miller camshaft, the ComprexTM transient response was still faster than the turbocharged engine. Using the same camshaft, the turbocharged engine took 2.5-times as long to reach the same torque. Water injection was used to increase the peak power output while respecting the temperature limitations. As the ComprexTM enables engine braking by design, we show that the use of friction brakes was reduced by two-thirds. Finally, a six-times faster catalyst warmup and an up to 90 ∘C higher exhaust gas temperature at the three-way catalytic converter added to the benefits of using the ComprexTM supercharger. The known drawbacks of the ComprexTM superchargers were solved due to a complete redesign of the machine, which is described in detail.

Investigation on the Role of Pd, Pt, Rh in Methane Abatement for Heavy Duty Applications

“…The decrease in NH3 can be attributed to two effects: the complete consumption of H2 by O2 (H2 concentration plot) and the oxidation of NH3 by O2. Our previous study on the same Pd/Rh catalyst suggests that the oxidation of NH3 starts above 150 °C and below 200 °C [49]. CO starts to be consumed at approximately 160 °C, much later than the start of the consumption of NOx, O2, and H2.…”

Transient Performance of Gas-Engine-Based Power System on Ships: An Overview of Modeling, Optimization, and Applications

“…Garrett [109] has tested and compared the influence of direct air injection and electric turbochargers on an engine's transient response and obtained similar results for these methods, resulting in a faster response than the baseline turbocharger. Norbert et al [110] compared the transient performances of a gas engine boosted by a pressure-wave supercharger and a conventional single-stage turbocharger. The response time is 2.5 times faster when using the pressure-wave supercharger due to its high boosting ability under low engine speed.…”

A Review of Engine’s Performance When Supercharging by a Pressure Wave Supercharger

“…From 2003 to the present, the ANTROVA AG subsidiary of the company 3prex AG Switzerland registered COMPREX as its trademark and in 2017 got the patent for a new modified Comprex PWS [94]. This new PW supercharger was improved by making some significant changes [95]: (i) the capability to turn off one of the two cycles described by the Comprex in a 360 • rotation, by completely closing one gas pocket valves-therefore, the PWS can have a comparable operation to a sequential charging system with variable geometry turbines; (ii) a new designed double-walled aluminum exhaust gas housing, with a water cooling system enclosed-this allows a second bearing to be installed in the hot side of the Comprex and both bearings to be fully encapsulated; (iii) an even divided rotor that shorten the gaps between the rotor and the end caps, resulting in the solving of the cold-start and low temperatures shortcomings of the old Comprex; (iv) the possibility to entirely close the exhaust gas channels that ensure a continually adjustable engine braking capability and avoid the cooling of the catalyst. ETH-Engineer Skopil from Antrova affirms that the new Comprex charger is the new supercharging solution and also a key to keeping the CO 2 problem under control [96].…”

“…The 2010s' and 2020s' were marked by numerous preoccupations for developing and implementing low-emission solutions, such as low-carbon fuels, as well as hybrid or full electric propulsion systems. Comprex was also reborn in the last decade and since 2019 the new Antrova Comprex was tested on engines using methane and hydrogen as fuels, having good results in comparison with the turbo charged similar engines [95]. Additionally, in commercial vehicles, such PW supercharged engines can bring about a rapid and costeffective reduction in CO 2 emissions.…”