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Issue: 403Section: Special Features17 October, 2006Honda Civic Hybrid TechnologyThe latest in the petrol-electric stableBy Julian Edgar, Courtesy of HondaClick on pics to view larger images
At a glance...Sophisticated triple(!) VTEC engineDual-plug sequential direct ignitionEight individually controlled coilsBattery electric motor assist4.6 litres/100Email a friendPrint article
Honda’s fourth-generation hybrid, the Civic Hybrid, combines a petrol-powered engine through an electric motor to boost power and reduced fuel usage and exhaust eobjectives. A Nickel-Metal Hydride (NiMH) battery load is supplied to capture and save power for the electrical motor.The improved Combined Motor Assist (IMA) system currently allows the Civic Hybrid to drive on electric power alone, provided the vehicle is travelling at much less than 40 km/h. The Civic Hybrid has a merged petrol/electric output of 85kW and also creates 170Nm. Quoted fuel intake is 4.6 litres per 100km, a conserving of 0.6 litres per 100km over the previous model. The Civic Hybrid is equipped via a Continuously Variable Transmission (CVT).During acceleration, the engine, or the engine functioning in tandem through the electric motor, propel the automobile. Throughout cruising, the petrol engine and/or the electric motor deserve to propel the vehicle, depending upon problems. Throughout braking, the petrol engine deactivates and the electrical motor acts as a generator to replenish the battery load. At a stop, the engine can enter an idle-soptimal mode to conserve fuel and also reduce emissions, with the engine turned off until the brake pedal is released.Engine Block Construction, Pislots and also Connecting Rods The 1.3 litre aluminium engine block and its internal components produce a lightweight package with very low friction qualities. To conserve weight, the block incorporates a thin sleeve building and construction. Friction-reducing steps include plateau honing, low friction pisloads, low tensile force piston rings and an balance out cylinder bore.Thin sleeve cylinder wall building and construction results in a reduction of the complete amount of aluminium supplied in the engine. Plateau honing lowers the friction level in between the pisloads and the cylinders by creating an ultra smooth surface. Plateau honing is a 2 phase machining process that provides 2 grinding procedures rather of the even more standard single honing procedure. This likewise enhances the irreversible wear characteristics of the engine.Low friction pislots made of aluminium alloy are lightweight and also have actually “micro-dimples” on the cylinder walls for improved lubrication. Offset cylinder bores aid minimise friction by positioning the crankshaft axis in a much more reliable alignment to the cylinder bore axis. This reduces friction resulted in by the side thrust of the pisloads versus the cylinder wall surfaces, just after top-dead-centre, as each piston begins its descent on the firing stroke.Connecting rods are high toughness forged steel systems that have been treated via a one-of-a-kind carbon process that hardens the surface and permits designers to usage a design that weighs less than a typical connecting rod.3-Stage i-VTEC through Variable Cylinder Management (VCM) The Civic Hybrid offers a 3-Stage i-VTEC valve manage system that gives normal valve timing, high output valve timing and also cylinder idling functions. The previous generation system in the 2005 Civic Hybrid offers 2-stage VTEC that provides normal valve timing and also 3-cylinder idling. The 3-phase system adds high output valve timing and 4-cylinder idling. Over the previous model, the high output valve timing contributes to the engine’s output boost of 9 percent, while the added cylinder deactivation reduces pumping losses by 66 percent to aid enhance electrical rejuvenation capability by 1.7 times.The Civic Hybrid’s single overhead camshaft (SOHC) cylinder head supplies a compact chain drive and a compact, low friction VTEC device. It offers a prevalent rocker shaft for both the intake and exhaust rocker arms. Placing all the rocker arms on one shaft eliminates the require for a 2nd rocker-arm shaft, so the valve system can be lighter and more compact. To alleviate friction, the rocker arms have integrated rollers.The compact valvetrain permits for a narrowhead angle (30 degrees) in between the intake and exhaust valves, which helps supply a much more powerful straight charge right into the cylinder chamber. The narrow angle valvetrain additionally allows for a much more compact burning chamber. The intake ports produce a swirl effect in the cylinder chamber that promote a well balanced and also also air fuel mixture as it enters the engine. This optimises the air fuel mixture for a cleaner, more reliable combustion. The new VCM (Variable Cylinder Management) system is an advanced form of the three-cylinder Cylinder Idling System used on the previous generation. VCM allows the regenerative braking device to reinsurance claim as much energy as possible during deceleration, while also enabling the electric motor to propel the auto in specific steady cruising cases.Because the electrical motor, which likewise acts as an electric generator, is attached directly to the crankshaft of the engine, the engine demands to carry out as little bit resistance as possible during deceleration to enable the generator to develop high levels of electrical energy and also charge the batteries. In a conventional engine, the pumping activity of the cylinders will actually provide a modeprice amount of resistance, or “engine braking,” throughout deceleration. VCM practically eliminates that effect.From a mechanical standsuggest, the three stage VTEC switching capabilities are made feasible by a rocker arm design via 3 hydraulic circuits that accommodays (a) low rpm VTEC switching on each cylinder’s intake and also exhaust valve and (b) high rate switching on the intake valve. Three oil passages inside the rocker shaft get oil from an exterior spool valve (controlled by the ECU based largely on throttle and rpm). The oil push from one of the three passperiods activates a combination of push pins inside the rocker arms for each of the intake and also exhaust valves. By relocating the pins, the intake valve rocker arms can follow one of two lobes on the camshaft (normal or high profile). Or, to deactivate the valves and also leave them closed, the pins are pushed in a direction that permit component of the intake and exhaust rocker arms to move through the camshaft and also not move the closed valves.Dual & Sequential Ignition with Twin Plug Sequential Ignition Control The twin plug sequential ignition regulate is part of the i-VTEC system and also helps facilitate an intense and fast burning process in the engine. The ignition regulate has eight ignition coils that are separately regulated according to a dynamic engine map regimen. The benefits are even more power, much less fuel usage and also decreased emissions. Honda’s patented twin plug sequential regulate mechanism is programmed to respond to engine rpm and load conditions. Because the system has actually eight individual ignition coils, it deserve to manipulate the ignition timing of each iridium-tipped spark plug.When the air/fuel mixture enters the combustion chamber, the initially plug located near the intake port ignites. Shortly after that, the second plug situated near the exhaust port ignites, accelerating the burning procedure by forcing the flame to more promptly propagate. The spark plugs deserve to also ignite at the same time under certain circumstances. This process outcomes in an extra finish combustion compared to a single plug device.Electronic Throttle Control An electronic drive-by-wire mechanism enhances the driving character of the Civic Hybrid. With smart electronics connecting the throttle pedal to the throttle butterfly valve in the intake manifold, the engine response and also IMA operation deserve to be optimised to suit the driving conditions and also to much better complement the driver’s expectations. By eliminating the direct throttle cable connection to the engine, the ratio between pedal activity and throttle butterfly activity have the right to be continuously optimised. This adjusteady “gain” in between throttle and also engine is a far-reaching action forward in drivecapability, which likewise permits for VCM to reduced all cylinders and drive via the electric motor only in the time of some cruising instances. A DC motor moves the throttle butterfly position in the intake manifold to change actual throttle place. To create the present driving conditions, the system monitors pedal place, throttle place, automobile speed, engine speed, calculated road slope and engine vacuum. This indevelopment is then used to specify the throttle regulate sensitivity.Programmed Fuel Injection (PGM-FI)The Civic Hybrid is equipped with a Programmed Fuel Injection (PGM-FI) mechanism. The device monitors throttle position, engine temperature, intake-manifold pressure, atmospheric push, exhaust-gas oxygen content, and intake-air temperature. It controls fuel shipment by multi-holed injectors installed in the plastic intake manifold. The ECU also tracks the operation of the engine with place sensors on the crankshaft and also camshaft.Lightweight Composite Resin Intake Manifold ChamberUpstream from the aluminium intake manifold, the engine’s intake manifold chamber is constructed of a compowebsite resin rather of aluminium alloy in order to conserve weight. The individual pieces that make up the manifold chamber are permanently linked via a vibration welding technique.Dual Scroll Air Conditioning Compressor A dual scroll hybrid air conditioning device reduces the load on the petrol engine by using a mix of engine power and an inner electric motor to drive two air conditioning compressors. These compressors have the right to act separately or together as dictated by the cooling needs of the Civic Hybrid’s automatic climate regulate system.Under normal problems, either of the two compressors cools the inner cabin individually depending on cooling demands and also the charge state of the IMA’s battery pack. On warmer days, the 75cc engine-mounted compressor acts as the single source of air-conditioning, while the 15cc motor-thrust compressor is in action as soon as the climate regulate is keeping a steady temperature or the auto is idle-quit. Under excessive ambient problems, cooling is gave by the 75cc belt-driven compressor attached to the engine and the 15cc, 144V motor-driven by an internal electric motor. When the air conditioning system is forced to use both the petrol engine and electric motor, the Civic Hybrid’s idle-speak function is temporarily disabled till cooling needs are lessened.Engine Mounts A new torque rod damper system included to the substructure helps mitigate rocking and isolate powertrain NVH from the passenger compartment. The engine mounts, one of which is hydraulic, and reinforcements in the engine compartment aid further minimize engine noise and vibrations.IMA System The 4th generation IMA mechanism is the a lot of powerful and also a lot of reliable to come out of Honda’s hybrid breakthrough regimen. (1st generation: Insight; second generation: Civic Hybrid; third generation: Accord Hybrid.) As with previous versions, the IMA device is composed of an ultra-thin DC brushless electrical motor mounted in between the petrol engine and the consistently variable transmission, and an Intelligent Power Unit (IPU) that stores electric power in a battery and controls the flow of power to and also from the electric motor.IMA Electric Motor Providing a supplepsychological power increase to the 1.3-litre 4-cylinder engine and also giving the Civic Hybrid the capability to cruise on its electric motor in certain cases, the IMA’s electrical motor is designed to provide as much as 15 kW and also 89Nm of extra torque to the Civic Hybrid’s engine. Mounted in between the engine and the CVT transmission, the IMA motor is a 70 mm thick DC brushmuch less architecture and provides a considerable amount of low-finish torque to assist acceleration, while also assisting in steady-state cruising and also hill climbing. In addition to offering supplemental motive power, the IMA motor acts as a generator in the time of deceleration and braking to recapture kinetic power and also recharge the IMA’s battery fill during regenerative braking. For this fourth generation of IMA motor, a new inner irreversible magnet was designed to boost output density and also make the motor even more reliable than previously. It also supplies level wire construction to increase wire density. The electrical motor has increased output power by 46 percent and maximum torque by 14 percent compared with the 2005 Civic Hybrid IMA motor. The electric motor is also more effective, now converting 96 percent (versus 94.6 percent performance of the 2005 Civic Hybrid IMA motor) of the accessible power right into motive energy in assist mode.IMA Intelligent Power Unit (IPU) Power for the IMA device is regulated via the Civic Hybrid’s Intelligent Power Unit. Located straight behind the rear seat, the IPU consists of the Power Control Unit (PCU) - the IMA’s command also centre, a rechargeable Nickel Metal-Hydride battery module, and an incorporated cooling unit.The Power Control Unit (PCU) electronically controls the flow of energy to and also from the IMA’s electric motor. Using the latest computer system chip technology, the PCU’s response time is quicker than the previous versions, and also a brand-new inverter and also DC/DC Converter assist add to the IMA’s overall boost in power. The battery load stores electrical energy in a bank of Nickel Metal-Hydride cells. This financial institution of 132 1.2-volt units stores approximately 158 volts of electrical power for the IMA motor compared to 144 in previous versions. A new Panasonic dual module casing reduces weight from previous hybrid battery packs and additionally permits it to boost performance of the electrical circulation. The 12 percent smaller battery pack provides more cargo area.The Combined Cooling Unit offsets the warmth created by the consistent flow of power to and also from the battery fill via an integrated cooling device placed directly on the battery pack’s outer box. Interior cabin air is continually flowed over the battery load and also re-circulated through a little vent placed on the rear seat shelf.Cooperative Regenerative Brake System Hybrid-powered vehicles recapture kinetic energy through regenerative braking and also store this energy as electricity in rechargeable battery packs. The Civic Hybrid is no different, as its IMA electric motor also acts as a generator that have the right to recharge its battery pack during braking, secure cruising, gentle deceleration, or coasting. New for 2006, a participating regenerative braking system debuts on the Civic Hybrid with the added capcapability to intelligently propercent braking power in between the hydraulic brakes and also the electrical motor to extract even even more electrical power from the vehicle’s kinetic power. Less reliance on the typical braking device and reduced engine pumping losses interpret into greater electrical rejuvenation (170 percent more than the 2005 Civic Hybrid) and also ultimately boosted fuel economic situation. When braking, a brake pedal sensor sends a signal to the vehicle’s IMA computer system (IPU). The computer system activates a servo unit in the brake system’s understand cylinder that prosections braking power in between the conventional hydraulic brakes and also the electrical motor to maximised rejuvenation. Previous versions of Honda’s IMA systems proportioned braking power at a pre-set price below the maximum rebirth threshost and also via no variable proportioning.Continuously Variable Transmission Honda’s Continuously Variable Transmission (CVT) is traditional tools on the Civic Hybrid and also provides a 9 percent broader array in between the maximum and minimum gear ratios to enhance acceleration and minimise engine rpm at high speeds. Unchoose a typical transmission through four of five gears that readjust the final drive proportion in steps, a CVT provides a steel belt and also a variable wheel to infinitely change the final drive ratio between a minimum and also maximum setting.
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The variable pulley via its angled interior sides moves in and out by hydraulic pressure to expand or mitigate the radius travelled by the steel belt.Improvements to the new CVT include:9 percent larger ratio range of 2.52 - 0.421:1 (previously 2.36 - 0.407:1)Final drive ratio of 4.94:1 (previously 5.58:1)Expanded pulley axial distance from 143 mm to 156 mmExpanded pulley ratio variety to 6.0 mm from 5.8 mmDouble hydraulic piston used on variable pulley rises pressure by 170 percentImconfirmed low friction building and construction for as a whole effectiveness increaseTorque handling capacity rises by 18 percentOverall, a CVT offers a greater fuel economic climate advantage than a conventional automatic transmission with gears. It helps the engine continue to be in its most reliable operating selection for both performance and also economy, and also the must shift gears is removed.2006 Civic Hybrid SpecificationsWheelbase (mm) - 2700 Length (mm) - 4550 Width (mm) - 1750 Height (mm) - 1430 Engine - 1.3-litre i-VTEC SOHC Power