Hesselman engine
The Hesselman engine was developed by the Swedish engineer Knut JE Hesselman around 1925. The Hesselman engine combines the properties of gasoline and diesel engines . Because of its multi-substance ability, it is also counted among the hybrid and multi-substance processes. and referred to as a medium pressure engine. It compresses pure air and can burn direct-injected heavy and light oil at compression ratios of 1: 8 to 1:10 . It runs on petrol for starting and shortly before parking.
Development history
In the early 1920s, Hesselman developed the first process for direct injection of gasoline with an open combustion chamber and charge stratification for vehicle engines .
functionality
The Hesselman engine is an engine with internal mixture formation, heterogeneous mixture, spark ignition, quality change at full load and quantity change at partial load and idling. The Hesselman process is a hybrid process and is technically close to the Otto process with direct injection. In order to achieve a heterogeneous fuel-air mixture, the intake air is set in rotation by shielding the inlet valve; shortly before top dead center , two jets of fuel are injected into the air vortex at low pressure using a nozzle , whereupon combustion is initiated with a spark plug . The start of injection, but not the end of injection, is variable; the injection ends 17 ° CA before TDC. The throttle valve position and the injection volume control of the fuel pump are used to regulate the engine output : During idling and low load, the torque is adjusted by throttling the intake air, otherwise the combustion would become unstable; at high load, however, the torque is adjusted by changing the amount of injected fuel. The engine is started with petrol and then switched to diesel fuel or kerosene, before switching off it is switched back to petrol to burn deposits in the cylinders. The compression ratios are between 1: 8 and 1:10, with an average final pressure of 17.5 bar and a final temperature of 400 ° C. The mean working pressure reaches over 7 bar at speeds below 1000 rpm and drops to 4.5 bar at the maximum speed of 2400 rpm. The engine has good power delivery and low fuel consumption compared to contemporary engines.
design type
The Hesselman engine contains the complicated parts of a diesel engine that are combined with parts of the igniter engine, but compared to the diesel engine it can be operated at lower pressures over the course of the entire working cycle. The engine was an in-line six-cylinder. Each cylinder had a separate injection pump that was driven by a camshaft. Below the pumps was a regulating shaft that measured the amount of injection for each cylinder, the difference between the individual cylinders not being more than 2%. Later engines had an in-line injection pump. The specific consumption at full load was between 220 and 280 g / PSh (300 and 381 g / kWh). During test drives with a six-ton truck, the consumption of gas oil was 20.2 l / 100 km.
use
All three Swedish car manufacturers, Scania-Vabis , Volvo and Tidaholms bruk built this engine. Scania-Vabis replaced the Hesselman engines with more modern machines from 1936 and Volvo from 1947. Waukesha Engines in the US built Hesselman engines under license.
swell
- Björn-Eric Lindt: Scania fordonshistoria 1891-1991, 1992, ISBN 91-7886-074-1
- Christer Olsson: Volvo trucks of yesterday and today, ISBN 91-86442-76-7
- Description and pictures of the engine
Individual evidence
- ↑ https://www.tekniskamuseet.se/lar-dig-mer/svenska-uppfinnare-och-innovatorer/jonas-hesselman/
- ^ Richard van Basshuysen: Otto engine with direct injection and direct injection: petrol, natural gas, methane, hydrogen. Springer Vieweg 2016. p. 17f.
- ↑ C. Zerbe: Mineral Oils and Related Products: A Handbook for the Laboratory. Springer 2014. pp. 675f.
- ^ Richard van Basshuysen: Otto engine with direct injection and direct injection: petrol, natural gas, methane, hydrogen. Springer Vieweg 2016. p. 17.
- ↑ a b c d Richard van Basshuysen (ed.): Otto engine with direct injection - process systems development potential , 3rd edition, Springer Vieweg, Wiesbaden, 2013, ISBN 9783658014087 , p. 16
- ↑ C. Zerbe: Mineral Oils and Related Products: A Handbook for the Laboratory. Springer 2014. p. 675.
- ↑ Harry R. Ricardo: The high-speed internal combustion engine. Jumper. P. 33.