VARIABLE VALVE TRAINS THE EVOLVING ENGINE Pierburg GmbH Alfred-Pierburg-Straße 1 41460 Neuss Germany www.kspg.com “We’re WORKING ON TOMORROW’s DOUBLY COMPLEMEntaRY AUTOMOBILE ENGINE.” 4-5 UniValve and FlexValve Dr. Dirk Hunkel, Director Business Unit Variable Valve Train Systems, Pierburg GmbH PRECISION FOR HIGH RPM 6-7 UniValve – Design and Function Gasoline or diesel? For years, these arch- inside the combustion chamber while BOTH ROBUst AND VERsatILE 8-9 rivals have charged ahead along their keeping the impact on the fuel con- FlexValve – Design and Function independent respective development sumption to a minimum. The fact that paths, each chiding the other with its variability in the air handling system 715/2007/EG 10 -11 own technical advances. Each system provides advantages for both engines is You want to see it in black and white? has its strengths, but also its weakness- undisputed. But variable valve trains es. The stoichiometric gasoline engine offer even more potential. Keywords are THE EVOLUTION OF YOUR ENGINE 12-13 features a highly efficient and cost displacement on demand, scavenging We work with you to produce a bespoke design. effective after-treatment system thanks and engine braking. to its three-way catalytic converter. But “VaRIABLE VALVE TRAIN SYstEMS ARE NOT 14-17 the fuel consumption has to be im- We’d like to show you what variable SOMETHING YOU JUst GET OFF THE SHELF.” proved. Diesel engines, on the other valve train systems can do. And we’d An interview with Heinrich Dismon, CTO hand, have already reached a very high like to assist you with your decision, efficiency. However, controlling their design concept and right on through KSPG IN A NUtsHELL 18 -19 emissions is more challenging and to SOP. We offer two different variable Who we are. What we do. mostly comes at the cost of reduced valve train systems, which we explain efficiency. The strategy here involves in the following. limiting the production of pollutants 2 3 DOUBLY COMPLEMENTARY UNIVALVE: MAKING FLEXVALVE: THE VALVE YOUR ENGINE FITTER TRAIN UPGRADE FOR FOR THE FUTURE. DIESEL AND HEAVY-DUTY ENGINES. Until now, the gas exchange of gasoline losses and pumping work lead to FlexValve is a compact, robust and including those for commercial vehicles, engines has always been associated favorable fuel consumption. efficient mechanical valve train system. which are sold in markets with differing with pumping losses. The reason is that It permits continuous variability emission standards. the throttle body has to be closed for An electrical actuator provides precise of valve lift over a broad range, even part load operation. and quick valve control from full valve lift allowing secondary opening of the valves, FlexValve offers the following down to zero valve lift. UniValve delivers if desired. This gives a lot of flexibility to advantages for diesel engines: UniValve fulfils engine designers’ outstanding fuel economy, dynamics influence the gas exchange process and faster warm up and improved longstanding goal of achieving adjust- and power. engine out exhaust gas temperature. after-treatment efficiency ment of cylinder filling to meet changing improved transient EGR control and/ operating conditions by means of UniValve provides the following In addition, FlexValve is modular, offering or faster T/C response thanks to variable valve timing. advantages for gasoline engines: various modules to change the function secondary valve opening high speed capability of the valve train system without having variable effective compression ratio UniValve has a compact, straightforward favourable frictional behaviour to change the cylinder head design adjustment of load and temperature design. The uncompromising use of good response and manufacture. This makes FlexValve for optimized combustion control roller contacts througout the system inherent cylinder deactivation an ideal solution for diesel engines, Compression release engine braking offers a high speed capability with low up to 12 % improvement in fuel mechanical losses. Reduced parasitic economy 4 Comparison 5 3 UNIVALVE: 4 PRECISION FOR HIGH RPM 1 Design and Function 5 UniValve features two mechanical cam How UniValve works 2 mechanisms in series. The UniValve The UniValve rocker (1), which rests rocker assembly is the heart of the on the control shaft (2), is guided by 6 system. The camshaft keeps it moving in the circular guide (3), and is set in an an oscillating motion and the assembly oscillating motion by the camshaft (4). subsequently transfers its movement to UniValve components the roller finger follower. Position and The UniValve rocker has a profile (5), Besides the typical valve train parts, such as a camshaft (4) and a orientation of the UniValve rocker are which is in contact to the roller finger roller finger follower (6), UniValve changed to give the desired family of follower (6). The profile includes a base has only three additional continuously variable valve lifts. circle and a lifting curve which together components: form a “swinging cam.” – UniValve rocker (1) UniValve can also completely deactivate – Control shaft (2) – Circular guide (3) individual valves, fully shutting down The control shaft (2) is shaped in a way, their respective cylinders. Now, that’s that its rotation controls the movement downsizing on demand. of the UniValve rocker. This varies the relative lengths of the base circle and Strong on every side the lifting curve used. Even greater potential is available with the use of UniValve on both the intake An electrical actuator steplessly turns and exhaust sides, particularly with turbo the control shaft, rapidly and precisely engines. to provide continuously variable position-control of the shaft and hence the valve lift. Contact: Dr. Michael Breuer All contact points are fitted with roller [email protected] bearings to minimise friction. 6 UniValve 7 4 FLEXVALVE: 3 BOTH ROBUST AND VERSATILE 5 Design and Function FlexValve is based on DuoCam, a twin Depending on the shapes and relative cam camshaft as the name indicates. angular positions of both cam groups, 6 An actuator, similar to a cam phaser, the FlexValve rocker either rotates about changes the angular relationship of the the pivot shaft (6) or generates a valve 7 shaft and tube and hence their associ- movement. Different cam contours are ated cam lobes, which are in contact with possible and through their design can the FlexValve rocker. The FlexValve rocker produce multiple valve openings. The “adds together” the two cam profiles. figures show two of the potential lift Thus, altering the angle between shaft curve families. and tube allows the valve lift to be varied. FlexValve is modular. This allows the FlexValve components FlexValve employs a DuoCam to The FlexValve system comprises a single engine to be built to different specifica- replace the conventional camshaft lobe (1), pinned to the inner shaft (2) of tions without cylinder head design and two other parts in addition to the the DuoCam shaft. The two outer cam changes. This provides the freedom to conventional valve train system components: lobes (4) are fixed to the tube (3). The implement conventional valve timing, – FlexValve upper rocker assembly (5) phasing between the lobes (1) and (4) a DuoCam version with variable valve – Return spring (7) may be varied via an actuator, (not shown timing of two groups of cam lobes, or for clarity). the full FlexValve system. The rollers of the FlexValve rocker (5) follow both cam profiles. This rocker pivots on a shaft (6), which connects it to both finger followers. The return spring Contact: (7) keeps all the parts in contact when Dr. Tim Lancefield the valves are closed. [email protected] 8 FlexValve 9 715/2007/EC 160 160 2500 This European Parliament regulation the penalty fees that will apply as of 2000 calls for the reduction of the average 2020 and the European fleet average 140 140 Actual in 2012: 135 g/km 1500 fleet consumption and the cutting of for 2012. 1000 carbon emissions produced by European 120 120 Target 2015: 130 g/km 500 automobile manufacturers to 95 g/km Our own surveys indicate up to 12 % by 2020. fuel reduction in the mapping area with 3.6 l Diesel the same or even improved full load and 4.1 l Gasoline 100 100 This chart shows the targeted values for emissions performance in g/km depicted emissions 2 Target 2020: 95 g/km penalty fee payment in for 2020 in for payment fee penalty O 2015 and 2020, as well as values that are 80 C 80 ISO in discussion for 2025. You’ll also find Proposal 2025: 68 – 78 g/km 1375* 60 60 2 4 6 1100 1200 1300 1400 1500 1600 1700 Fuel consumption kerb weight in kg shown as l/100 km * ∅ Mean kerb weight of European motor vehicles 12% Up to 12 % fuel consumption reduction This chart shows the targeted values for 2015 and 2020, as well as values that are in discussion for 2025. You’ll also find the penalty fees that will apply as of 2020 and the European fleet average for 2012. Our own surveys indicated a 12 percent reduction in consumption with the same or even improved full load and emissions performance. EU TARGETS FOR 2020 95 g/km CO2 4.1 l/100 km average Gasoline fleet consumption 3.6 l/100 km average Diesel fleet consumption 10 Facts and Figures 11 THE EVOLUTION We work with you to produce a OF YOUR ENGINE bespoke design for the future. A component can perform to its full No, we design your valve train system potential only if it integrates perfectly to meet your specific requirements. into its technical environment, which That’s only possible if we work closely is why we wouldn’t sell you an off-the- with you.