{{infobox aero engine |name= Bz.IV |image = Benz BZ 4S Aircraft Engine.jpg |caption = A Benz Bz.IV at the National Air and Space Museum's Udvar-Hazy Center (2017) |engine_type= Inline piston engine |national_origin = Germany |manufacturer= Benz |first_run= c. 1916 |major_applications= |number_built = 6,400 |developed_from = Benz Bz.III |developed_into = |variants_with_their_own_articles = }}
The '''Benz Bz.IV''' was a German six-cylinder, water-cooled, inline engine developed for aircraft use. Deliveries began in 1916, and some 6,400 were produced.
==Design and development== The Bz.IV was a dual-camshaft design, with two intake and two exhaust valves per cylinder. The cylinders were cast iron surrounded by a sheet metal cooling jacket. The crankcase was aluminium and pistons were initially steel but later versions had aluminium pistons. A high compression version of the engine (Bz IVsü) was produced from 1917 onwards.<ref name=":0">{{Cite book |last=Düsing |first=Michael |title=German & Austro-Hungarian Aero Engines of WW1 |date=2022 |publisher=Aeronaut Books |isbn=9781953201515 |volume=1 |pages=197–205}}</ref> In February 1918, pistons from a Bz.IV were the first captured aluminium pistons to be examined by the British Ministry of Munitions.<ref>{{Cite journal |journal=Flight |title=Report on Aluminium Pistons from 230 HP Benz Engines |date=4 July 1918 |url=http://www.flightglobal.com/pdfarchive/view/1918/1918%20-%200746.html }}</ref>
==Variants==
;IV : (1916) Main production variant produced by Benz & Cie.
;IVmarta : (1916) Licensed production of the Benz Bz.IV in Austria-Hungary by ''Magyar Automobil Részvény Társaság Arad'' (MARTA). The Marta produced version was heavier and had a lower compression ratio than the German original.
;IVsü : (1917) Overcompressed version producing {{convert|275|hp|kW|abbr=on|order=flip|0}} at altitudes above {{convert|2000|m|ft|abbr=on|0}}. Also known as the IVs, IVü or IVaü. The "ü" in the model description stands for überverdichtet (German: "overcompressed”) while the "s" denotes the use of steel cylinder liners.<ref name=":0" />
==Applications== {{columns-list|colwidth=30em| * AEG C.VI * AEG J.I * AGO C.IV * Albatros C.VII * Albatros C.XIV * Albatros J.I * Chitty 2 (racing car) * DFW C.V * Dobi-II * Friedrichshafen FF.49 * Friedrichshafen G.II * Halberstadt C.III * Halberstadt C.V * Junkers J.I * LFG Roland C.III * LVG C.VI * NAVO RK-P4/220 * Pfalz D.XII * Pfalz D.XIV * Siemens-Schuckert R.III * Siemens-Schuckert R.IV * Siemens-Schuckert R.V * Siemens-Schuckert R.VI * Zeppelin-Staaken R.IV * Zeppelin-Staaken R.XVI }}
==Specifications== {{pistonspecs |<!-- If you do not understand how to use this template, please ask at Wikipedia talk:WikiProject Aircraft --> <!-- Please include units where appropriate (main comes first, alt in parentheses). If data are missing, leave the parameter blank (do not delete it). For additional lines, end your alt units with </li> and start a new, fully-formatted line with <li> --> |ref=<ref name=JAWA1919>{{cite book|last=Grey|first=C.G.|title=Jane's All the World's Aircraft 1919|year=1969|publisher=David & Charles (Publishing) Limited|isbn=978-0-7153-4647-1 |pages=1b to 145b|edition=Facsimile}}</ref> |type=6-cylinder, water-cooled, inline aircraft piston engine |bore={{convert|145|mm|in|abbr=on|1}} |stroke={{convert|190|mm|in|abbr=on|1}} |displacement={{convert|18.825|L|cuin|abbr=on|1}} |length={{convert|1,990|mm|in|abbr=on|1}} |diameter= |width={{convert|530|mm|in|abbr=on|1}} |height={{convert|1,150|mm|in|abbr=on|1}} |weight={{convert|370|kg|lb|abbr=on|1}} |valvetrain=Twin inlet and exhaust valves operated by pushrod actuated double rockers |supercharger= |turbocharger= |fuelsystem=Two Benz 2-jet carburettors feeding three cylinders each |fueltype=Gasoline specific gravity 0.72 |oilsystem=Pressure feed at {{convert|28|psi|MPa|abbr=on|1|disp=flip}}: 50% Vacuum Heavy, 50% Sternol |coolingsystem=Water-cooled |power={{convert|170|kW|hp|abbr=on|1}} at 1,400 rpm |specpower= 9.1 kW/L (0.2 hp/cu in) |compression=4.91:1 |fuelcon={{convert|150|imppt|L|abbr=on|1|disp=flip}} / hour |specfuelcon= 0.495 L/kW/hr (0.65 pts/hp/hour) |oilcon={{convert|4.5|imppt|L|abbr=on|1|disp=flip}} / hour |power/weight= 0.3796 kW/kg (0.231 hp/lb) }}
==See also== {{aircontent <!-- first, the related articles that do not fit the specific entries: --> |see also=
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<!-- relevant lists that this aircraft appears in: --> |lists= *List of aircraft engines <!-- For aircraft engine articles. Engines that are of similar to this design: --> |similar engines=
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==References== {{Reflist}}
==Bibliography== *{{cite book|last=Grey|first=C.G.|title=Jane's All the World's Aircraft 1919|year=1969|publisher=David & Charles (Publishing) Limited|isbn=978-0-7153-4647-1|pages=1b to 145b|edition=Facsimile}} * Kroschel, Gunter and Helmust Stützer. (1977) ''Die deutschen Militarflugzeuge 1910-1918'' Wilhelmshaven: Lohse-Eissing Mittler.
==External links== {{Commons category|Benz Bz.IV}} * [https://web.archive.org/web/20070210052043/http://www.wwiaviation.com/engines/Engines.html]
{{Benz aeroengines}}
Category:1910s aircraft piston engines