Engines and transmissions: Extra power coupled with far lower fuel consumption

Sep 11, 2007
  • Four-cylinder engines improved in many respects
  • Fuel consumption cut by up to twelve per cent
  • C 200 CDI and C 220 CDI exceptionally smooth
  • Six-speed transmission with AGILITY CONTROL gearshift
With a remarkable boost in output of over 13 per cent combined with a reduction in fuel consumption of up to around 12 per cent, the engines not only inject the new Estate with a distinctly lively character, they make it possible to drive in an environmentally responsible and economical manner at the same time.
Mercedes-Benz has paid particular attention to further development of the four-cylinder engines. In the petrol range, the output of the entry-level C 180 KOMPRESSOR has increased from the previous 105 kW/143 hp to 115 kW/156 hp, with maximum torque improved by 4.5 percent from 220 to 230 Newton metres.
The C 200 KOMPRESSOR develops 15 kW/20 hp more than before. It has an output of 135 kW/184 hp and generates its maximum pulling power of 250 Newton metres from 2800 rpm.
These modified engines considerably improve the performance and fuel consumption of the four-cylinder models. When accelerating from standstill to 100 km/h, the C 200 KOMPRESSOR Estate is 0.6 seconds faster than its predecessor. The fuel consumption make equally impressive reading: despite the increase in power output, the Estate burns 0.9 litres less of premium per 100 kilometres than before.
The measures implemented in the four-cylinder petrol units to achieve this higher output and increase in torque include the use of modified engine management, a more dynamic supercharger and improved pistons. With compression ratios of 9.3 : 1 (C 180 KOMPRESSOR) and 8.5 : 1 (C 200 KOMPRESSOR), these four-cylinder engines are designed to run on unleaded premium petrol (95 RON).
The V6 engines for the new Estate remain virtually unchanged from its predecessor, with a choice of three power units developing between 150 kW/204 hp and 200 kW/272 hp. Their technical highlights include variable camshaft adjustment for the intake and exhaust sides, a variable intake module and intake ports with tumble flaps. This technology results in enhanced power and torque yield, while cutting fuel consumption at the same time. With one of the V6 engines under the bonnet, fuel consumption in the new Estate is reduced by up to 0.3 litres per 100 kilometres.
Key data for the petrol engines in the new Estate at a glance:
C 230 Estate
C 280 Estate
C 350 Estate
4 in-line
4 in-line
1796 cc
1796 cc
2496 cc
2996 cc
3498 cc
115 kW/
156 hp
135 kW/
184 hp
150 kW/
204 hp
170 kW/
231 hp
200 kW/
272 hp
Max. torque
230 Nm
at 2800-4600 rpm
250 Nm
at 2800-5000 rpm
245 Nm at 2900- 5500 rpm
300 Nm at 2500- 5000 rpm
350 Nm at 2400- 5000 rpm
0 - 100 km/h
9.8 s
8.8 s
8.6 s
7.5 s
6.5 s
Top speed
218 km/h
228 km/h
232 km/h
242 km/h
250 km/h
Comb. fuel consumption
7.7 - 7.8 l/100 km
7.8 - 8.0 l/100 km
9.3 - 9.5 l/100 km
9.4 - 9.6 l/100 km
9.9 - 10.1 l/100 km
Diesel engines: four-cylinder units with considerably more power and torque
Advancement of the four-cylinder units was also the main focus for the diesel engines. While generating significantly more power and torque, the common-rail units in the new Estate now consume up to 0.8 litres of diesel less per 100 kilometres than in the preceding model series. This equates to a fuel saving of 11.8 per cent. In the New European Driving Cycle (NEDC), the C 200 CDI and C 220 CDI require just 6.0 and 6.1 litres of fuel respectively to travel 100 kilometres – which means that both diesel models are able to make their fuel tank capacity of 66 litres last for over 1000 kilometres.
The engineers in Stuttgart have made further improvements to the crank assembly, the turbocharger and the common-rail direct injection system of the four-cylinder engines, modifying over 90 components in the process. For example:
  • The air ducting in these engines was improved in terms of pressure losses and acoustic characteristics.
  • The intercooler and turbocharger were modified to further improve the responsiveness of the CDI engines at lower rev speeds, while reducing nitrogen oxide emissions yet again.
  • The cylinder head has a new cooling concept which enables superior power delivery.
  • Mercedes engineers have enhanced the injection system, making further progress in demand-based fuel metering, for example, by the use of a structure-borne sound detector. The benefits of this include a noticeable reduction in combustion noise.
  • Ceramic glow plugs, which attain higher temperatures than the previous metallic glow plugs, improve the starting and cold-running characteristics of the diesel engines.
  • Balancer shafts in the crankcase, which counter-rotate at twice the speed of the crankshaft, compensate inertial forces and ensure the smooth, silent running typical of a six-cylinder engine. This Lanchester dynamic balancer is now also standard equipment in the C 200 CDI.
As a result of this comprehensive raft of measures, the power output of the new C 200 CDI has been upped by eleven per cent compared to its predecessor, with 100 kW/136 hp versus the previous 90 kW/122 hp. The C 220 CDI develops a peak output of 125 kW/170 hp (previously 110 kW/150 hp), and musters up 400 Newton metres of torque from 2000 rpm -- around 18 percent more than before. Key data for the CDI models at a glance:
C 200 CDI Estate
C 220 CDI Estate
C 320 CDI Estate
4 in-line
4 in-line
2148 cc
2148 cc
2987 cc
100 kW/136 hp
125 kW/170 hp
165 kW/224 hp
Max. torque
270 Nm
at 1600-3000 rpm
400 Nm
at 2000 rpm
510 Nm
at 1600-2800 rpm
0 – 100 km/h
10.8 s
8.9 s
7.9 s
Top speed
208 km/h
224 km/h
245 km/h
Comb. fuel consumption
6.0 - 6.1 l/100 km
6.1 l/100 km
7.1 - 7.4 l/100 km
The sophisticated V6 diesel engine remains unchanged in the C-Class Estate range. With an output of 165 kW/224 hp and a maximum torque of 510 Newton metres, the six-cylinder unit is one of the most powerful in its class. This tremendous pulling power is available between 1600 and 2800 rpm, giving the V6 a torque delivery curve which is unrivalled in this displacement class.
These results are in a large part due to the third-generation common-rail direct injection technology, featuring piezo injectors. These operate more rapidly and precisely than the previous solenoid valves, and ensure particularly fine metering of the fuel supply to the cylinders. This allows fuel injection to be adjusted to the current load and engine speed even more precisely -- fuel can be injected as many as five time per power stroke at a peak pressure of up to 1600 bar. Electrically controlled intake port shut-off modifies the swirling motion of the intake air as it enters the cylinders, again optimising the combustion process with the aim of further reducing fuel consumption and exhaust emissions.
Emissions control: particulate filter as standard on the CDI models
Mercedes-Benz equips the new C-Class Estate diesel models with a maintenance-free diesel particulate filter as standard (depending on country). This is downstream of an oxidising catalytic converter. The exhaust system is made entirely of stainless steel, and is of twin-pipe construction in the C 320 CDI.
The emissions control system for the four-cylinder petrol engines is also a two-stage process, consisting of a close-coupled three-way catalytic converter with control and diagnostic sensors, plus an additional underfloor catalytic converter. In the V6 models, air-gap insulated exhaust manifolds and double-wall insulated catalytic converter funnels ensure that the emissions control components quickly reach their optimal operating temperature after a cold start. The V6 exhaust system has a twin-pipe arrangement with chrome tailpipes, and no underfloor catalytic converters are required. As in the diesel models, the exhaust system of the petrol models is completely of stainless steel.
Transmission: AGILITY CONTROL gearshift for rapid, precise gear changes
With the exception of the C 350, all the models in the new C-Class Estate range are equipped as standard with a six-speed manual transmission with AGILITY CONTROL gearshift for short, precise shift travel. Mercedes engineers have developed a new manual transmission for the C 320 CDI: wider gear wheels, a third bearing level for the layshaft and main shaft, as well as a larger clutch enable this transmission to handle the high torque of the six-cylinder engine (510 Newton metres). The top-of-the-range C 350 leaves the factory equipped with 7G-TRONIC, the world’s only seven-speed automatic transmission. This is also available for the other V6 models in the range as an option. The four-cylinder models, meanwhile, are optionally available with a five-speed automatic transmission.
In the optionally available level control for the C-Class Estate, all the components are integrated in the damper.
Mercedes-Benz has placed particular emphasis on refining its four-cylinder engines. In the petrol engine line-up the output of the C 180 KOMPRESSOR entry-level model has been increased from the previous 105 kW/143 hp to 115 kW/156 hp, maximum torque has been increased by 4.5 percent from 220 to 230 Newton metres. The C 200 KOMPRESSOR delivers an extra 15 kW/ 20 hp, producing 135 kW/184 hp, and maximum torque of 250 Newton metres from 2800 rpm.
With a remarkable output boost of over 13 percent and an increase in torque of around 18 percent, the engines give the new C-Class its athletic performance.
With the exception of the C 350, all the new C-Class models come as standard with a six-speed transmission featuring AGILITY CONTROL gearshift, which offers short gearshift travel and precise action. For the C 320 CDI the Mercedes engineers have developed a new manual transmission: wider gear wheels, a third bearing plane for the countershaft gear and main shaft as well as a larger clutch mean this transmission can transfer the high torque from the six-cylinder unit (510 Newton metres).
The ultra-modern V6 diesel engine remains unchanged in the C-Class line-up. Producing 165 kW/224 hp and maximum torque of 510 Newton metres, this six-cylinder engine is among the most powerful engines in its class.