Gas engines (DAY) – VW Golf 4 and Bora
Five-valve engines per cylinder
Only one Golf engine: 1,8 GTI Turbo, it is equipped with a head containing five valves for each cylinder. Two other gasoline engines: of a capacity 1,4 l and 1,6 l have four valves per cylinder, while all other engines – traditionally two valves per cylinder.
What theoretical advantages does a five-valve engine per cylinder have?, in which two exhaust and three intake valves are to improve gas exchange? The answer seems simple: through the three valves, more mixture can enter the cylinder in a short time, than two and much more than one valve. The degree of cylinder filling in one intake stroke should therefore be much higher.
So far, The five-valve engines per cylinder, however, did not break through in the market. Fuel consumption and power rates are no better than comparable engines with fewer valves.
Motors 1,4 dm3 16V typu AHW, AKQ, APE i AXP
Engine 1,4 l with four valves per cylinder achieves power 55 kW (75 KM) at 5000 rpm. It has two overhead camshafts, one of which is driven by a toothed belt from the crankshaft. The drive of the second shaft has a different solution than in all other VW engines with two camshafts. It is not a chain, but a second toothed belt. One of the rollers controls the inlet valves via the levers, and others (located on the back) outlet valves.
The light alloy head and crankshaft with five main bearings resemble other VW engines. The oil pump, on the other hand, was placed differently: behind the timing drive wheel. This engine has a new injection system 4 AV firmy Magneti-Marelli, integrated into the ignition system as part of the common engine control system.
Motors 1,4 l are also fitted with the Motronic ME injection and ignition system 7.5 (instead 4 OF) from Bosch. This variety is marked with the letters APE. Since May 2000 Year, the APE engine is built as the AXP. It meets the European EU exhaust gas purity standard 4.
The designation of the individual engine variants and its serial number are shown on the sticker, located on the toothed belt cover. This information is repeated on the crankcase at the gearbox and on the information plate in the luggage compartment. The engine letter designation is also stamped on the car nameplate.
Motors 1,6 dm3 typu AEH, AKL, APF, ATN i OFF
None of the previous Golf generations can be found among these engines either. AEH and AKL motors are made of aluminum and gray cast iron, they have eight valves and reach power 74 kW (100 KM) at rotational speed 5600 rpm. The camshaft mounted in the head is driven by a toothed belt from the crankshaft. The camshaft controls the angled intake and exhaust valves via hydraulic tappets.
There is no intermediate shaft in this engine. The oil pump is chain driven from the crankshaft. It also lacks a conventional ignition distributor. It was replaced with a dual spark ignition system with two ignition coils, which regulate ignition. This system is integrated with the petrol injection system, as part of the Simos engine control system 2 by Siemens. The AKL engine meets the D3 exhaust gas purity standard. Since May 1999 r. engine 1,6 l type APF has power 100 KM and is equipped with the Simos control system 3.3, to meet the stricter exhaust gas purity standard D4.
Engine designation (letters and serial number) stamped on the front of the fuselage next to the connection between the engine and the gearbox. It is also located on a sticker on the toothed belt cover. The letter part of the designation includes the car nameplate.
From January 2000 r. Golfs are equipped with a new one, a sixteen-valve version of this engine with the Magneti-Marelli 4LV injection-ignition system. The engine is marked with the letters ATN. His strength is 77 kW (105 KM). The Golf and Bora ATN engines are only available with a five-speed mechanical gearbox. With maximum torque 148 Nm (at 4500 rpm) this new drive unit makes the car more dynamic. Lowered by 11% fuel consumption (medium 6,8 l/100 km) and the emission of harmful substances in the exhaust gas (compliance with the D4 standard). The Golf reaches speed with a new engine 100 km / h w 10,5 seconds. Its top speed will grow up 192 km/h. Sold from May 2000 r. modernized version of this engine, type AUS, already complies with the European EU exhaust gas purity standard 4.