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Friday, February 22, 2008

Honda Civic Type S details



The 1.8-litre SOHC i-VTEC engine contains the finest of Honda's VTEC technology and control systems expertise and introduces a further innovation to boost environmental performance by combining delayed intake valve closure with a wide open throttle valve during low-load driving conditions, pumping losses are reduced to the benefit of fuel economy.

In conventional petrol engines, the accelerator pedal is directly connected to a throttle valve that opens and closes, adjusting the volume of intake air. Under low-load conditions (i.e. when the driver is pressing lightly on the accelerator pedal) the throttle valve is opened just slightly. This narrowing of the intake passage causes resistance, pumping losses and has a negative impact on fuel economy.

The 1.8-litre i-VTEC engine adopts a different approach. Its two sets of cams one designed for high output, the other fuel economy intelligently adjust valve timing and lift. During acceleration and other high-load conditions, the high output cams help deliver a superior driving performance. During cruising and other stable low-load driving conditions, the fuel economy cams retard the closure of the intake valve and the throttle valve is opened wide. In this position, the output would normally be very high but since the intake valve closure is delayed, some of the air/fuel mixture is momentarily expelled back out of the combustion chamber, minimising unnecessary output and thus improving fuel economy.

Thanks to this synchronised operation of the intake and throttle valves, output is optimised and pumping losses are minimised. Meanwhile, the drive-by-wire throttle works together with the switch between high output cams and fuel economy cams, to provide highly precise throttle control for smooth driving with minimal torque variation.

The cruising mode is detected if the water temperature is over 60ºC, if second or a higher gear is in use, if the vehicle speed exceeds 6mph and if the engine is revving between 1,000 and 3,500rpm.

In pursuit of even higher fuel economy, the new 1.8 i-VTEC engine also incorporates the latest friction reducing technologies. The piston skirts are shot with a solid lubricant, molybdenum disulphide, while an ion plating process is used on the piston rings to ensure reduced friction. Plateau honing of the cylinders results in a smoother surface and improved oil film retention. Friction is reduced by approximately 10 per cent as a result.

Through this combination of new VTEC technology and comprehensive friction reduction measures, the new engine realises a six per cent improvement in fuel economy compared to a 1.7-litre engine and during cruising it delivers fuel economy on a par with that of a 1.5-litre engine. Performance is improved at all engine speeds to ensure lively response, while special attention has been paid to increasing low to mid-speed torque.

For the intake system variable length intake manifolds are implemented. Controlling the effective length of the intake manifold making it longer at low rpm and shorter at higher rpm ensures that the optimum intake ram effect is maintained to deliver torquey driving performance throughout the rpm range.

Also introduced with this engine are piston oil jets, more normally associated with high performance engines. The resulting superior cooling ensures improved durability against knocking, allowing the engine to run with a high compression ratio of 10.5:1.

These enhancements combine to achieve class-leading performance that's on a par with a 2.0-litre engine: maximum output of 140PS at 6,300rpm and a maximum torque of 128lb.ft at 4,300rpm. With an acceleration time from 0 to 62mph of 8.9 seconds (i-SHIFT 10.9 seconds) and a Combined fuel consumption of 42.8mpg (43.5 i-SHIFT), it establishes new standards for this size of engine and even betters some competitors fitted with 1.6-litre engines.

Along with improved fuel economy, the new engine offers cleaner emissions performance. The airflow meter and linear airflow sensor, together with the latest control technology, achieve extremely precise control over the air/fuel ratio and contribute to cleaner exhaust emissions. A key role is also played by the integrated cylinder head and exhaust manifold with two catalytic converters positioned immediately after the manifold.

The engine is also light and compact thanks to an all aluminium lower block and plastic used in the head cover, chain guard and chain tensioner arm. Aluminium rocker arms and high strength cracked connecting rods provide a significant reduction in the inertial mass of moving parts.

The integration of the cylinder head with the exhaust manifold both saves space and generates an important weight reduction (0.58kg). The combined assembly of the manual transmission bracket, the chain cover and the oil pump further reduce the engine's weight (0.3kg) and size (15mm), besides diminishing the parts number. Overall the engine is both lighter (5kg) and shorter (13mm) than a conventional

2.2 DOHC i-CTDi

The acclaimed 2.2-litre i-CTDi diesel engine has established a strong reputation thanks to its outstanding performance, low consumption and environmental protection. As the first in-house developed diesel engine in Honda's history, it has lived up to high expectations and in true Honda fashion, it extends the boundaries of diesel technology to give one of the best all-round packages on the market.

With a displacement of 2,204cc, the i-CTDi engine's advanced design and all-aluminium construction deliver 140PS at 4,000rpm and maximum torque of 251lb.ft at just 2,000rpm. It's a transversely mounted, 4-cylinder unit, with DOHC, four valves per cylinder, balancer shaft, second generation common rail direct injection, and variable nozzle turbocharger with intercooler. The strength-in-depth of the engine is exemplified by consumption figures in the combined cycle of 54.3mpg and acceleration from standstill to 62mph completed in 8.6 seconds.

Although the engine structure is not identical to the engine used in the Accord, CR-V and FR-V, the torque and output curves are exactly the same as those of the Accord although the way they are produced is slightly different.

The intake and exhaust systems have also been modified in order to accommodate the engine under the Civic Type S's relatively low bonnet. The grille-less design was a technological challenge; usually the intercooler is placed between the bumper and the radiator, but in this case it was positioned within the wing. The EGR cooler is also deleted to free up space, but the reduced EGR is compensated by the lower weight and better aerodynamics of the Civic Type S.

Other items unique to Civic include the frame, con rods, a new ancillary belt arrangement (to accommodate the EPS), oil pan (to receive the oil level sensor), while the oil filter and chain case are smaller to provide more under bonnet room for pedestrian protection.

Honda's reputation for consistently bringing clever solutions and creative thinking to whatever new area of technology it has chosen to pursue continues with the 2.2 i-CTDi engine; producing a class-leading diesel engine has been as much about materials science and production technology as it has about engine architecture.

Employing a series of advanced technologies and crucial attention to detail, both in terms of construction and operation, has delivered an engine that is light in weight, compact, yet immensely strong, and delivers optimum combustion characteristics.

Core intelligent combustion technologies include optimum use of the combustion chamber, a continuously variable swirl control valve, a common rail system, variable nozzle turbocharger and an electrically operated EGR valve. Achieving exceptional refinement, NV reduction technologies include offset cylinders, a second order balancer shaft and an acoustic engine cover, while friction is minimised through technologies such as roller follower rocker arms. Close coupled and under floor catalytic converters contribute to the low emissions performance.

The common rail injection system, providing pressures up to 1,600bar, allows close regulation of injection pressure and timing to give optimum performance across all driving conditions. A small amount of fuel introduced prior to the main injection the pilot injection helps lower combustion noise.

This common rail system closely interacts with the variable nozzle turbocharger to ensure optimum control over intake pressure, facilitating higher intake pressures at a lower speed, as well as better fuel economy and fewer harmful emissions through lean burn combustion.

6-speed manual transmission

The Type S's 6-speed manual transmission features an improved shifting action thanks to a shorter synchro sleeve stroke, a linkless rotation select structure, detent bearings for reduced friction and higher capacity bearings. Other upgrades include a variable lever ratio shift arm and a new gear specification with better inter-meshing from third to sixth gears.

Every component was also carefully analysed and where possible reduced in size and weight (for example the gear synchroniser), without compromising reliability. The result was so successful, that Honda's 6-speed manual transmission is even more compact in size than the 5-speed transmissions from some competitors.

Honda i-SHIFT 6-speed automated manual transmission

Type S 1.8 models can also be equipped with i-SHIFT automated manual transmission. The clutch and change actuator ensure good fuel economy, while the sequential paddle shift allows sporty gear shifting. The Transmission Central Unit is used to control the clutch with hydraulic power generated by a direct current (DC) motor that replaces the operation of a manual transmission clutch pedal. Gear changes are particularly smooth without compromising the system's sportiness.

Switching between Auto and Manual modes is via a button placed beside the gear lever or through the steering wheel mounted paddles. During manual mode operation, the selected gear is displayed to the left of the speedometer.

Different shift maps are employed depending on the driving conditions so when the Type S is being driven downhill, the system will shift down to provide engine braking. Similarly, the system will not shift through a corner if there is any possibility of upsetting the car's balance.

There are other system safeguards. At low rpm the system will not shift up, even if it is instructed by the driver to do so, thus preventing malfunction and knocking. And it automatically shifts up 500rpm before the red zone in order to avoid damaging the engine by over revving. When the car stops in fourth gear, the system will automatically shift back to first either in automatic or manual mode. The driver may also choose to start in second gear in manual mode.

There are other shifting restraints determined by operation speed. When the manual operation time is shorter than the shifter operation of 110ms the shift is not changed. On the other hand, there is also a jump shift restriction (shifting is partially restricted depending on the vehicle speed).

The shift lever requires only a short 13.5mm movement to select the next gear so emulating a sporty driving feel. Furthermore, reverse is in the conventional manual transmission position, thus permitting selection without requiring a visual check from the driver. When the gear is selected directly from N (neutral) after starting the engine, the auto mode is activated. Finally, manual shifting is possible even in auto mode, as long as the paddles are activated.

Insurance ratings, warranties & maintenance

Considerable effort has gone into designing front and rear body structures that do not result in expensive repair bills in the event of slow speed impacts. The light crash damageability assessment (DDV/Thatcham standard) has proved very positive, and only required the replacement of plastic parts, considerably reducing repair costs and enabling Civic to receive more favourable insurance ratings in the UK.

Paintwork anti-scratch resistance has been enhanced by adopting a hard coating technology.

The Civic also upgrades its warranties. A newly developed wax has been applied to the body making it possible to extend the perforation protection warranty from six to 12 years.

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Source: Honda Motor Corporation

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Honda Civic Type S


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