GE’s J920 Gas Engine — 10.4 MW Power and more than 50 % Electrical Efficiency

Current State and Development Trends in the Field of Large Diesel and Gas Engines

“…Thermodynamically efficiency of the large four-stroke engines appears to have been rising at a rate of 0.25% per year (Figure 16, left) for the Diesel and 0.3% for the gas fuel ( Figure 16, right) in the last two decades (note that the ordinate in the LHS plot was in the original paper incorrectly labelled, and has been corrected by the present author in the image below). Both trends appear to have continued to the present with the already mentioned Wärtsilä 31 engine (the efficiency figure has not been published, but with the BSFC of 165 g/kWh it is likely to be about 50%), and the newest Jenbacher J920 gas engine genset with an electrical efficiency in excess of 50% has the engine efficiency of more than 51% [52]. Figure 16.…”

“…The performance figures of the new J920 gas engine came about through a comprehensive system-based analysis optimization of the already efficient first version of the engine (electrical efficiency of 48.7%, [53]). Referring to the comparison of the respective contributions of the fundamental thermodynamically and mechanical processes in the first and second engine versions, presented in Figure 17 below, it is seen that the performance improvement came about through reductions of the losses due to incomplete combustion, gas exchange, and friction [52]. Figure 17.…”

“…Figure 17. Reduction of losses in the Jenbacher J920 gas engine design process [52] Summarizing, modern four-stroke large engines are capable of meeting the current exhaust legislation while keeping or improving the engine efficiency, and hold promise for the future. The current development state has been attained by intensive R & D efforts which, given the importance and the omnipresence of these engines, are going to continue.…”

Scaling Performance Parameters of Reciprocating Engines for Sustainable Energy System Optimization Modelling

“…State-of-the-art engines at the high end of the scale include the Jenbacher J920 engine, a 20-cylinder, 310 mm bore engine with a thermal efficiency of 51% at an engine load of 24 bar BMEP. This engine delivers 10.4 MW of electrical power at an operating speed of 1000 rpm [87]. Similarly, the 20-cylinder MAN V35/44G engine with two-stage turbocharging and a bore size of 350 mm achieves a 24.2 bar BMEP with an efficiency of 51%, resulting in an output power of 12.8 MW at an operating speed of 750 rpm [88].…”

“…To conclude this part, a case study was conducted on a set of heavy-duty SI gas engines equipped with a pre-chamber spark plug and operating under lean conditions. The data set comprises 28 engines, with data drawn from both the scientific literature [67,85,86,[90][91][92][93][94][95][96][97][98][99][100][101][102][103][104] and documentation from commercial OEMs [87][88][89][105][106][107][108]. Figure 1 depicts the only scaling law for torque versus the displacement volume.…”