2003 Honda Civic Hybrid -- Powertrain - Engine

CIVIC HYBRID ENGINE
1.3-Liter i-DSI 4-Cylinder Engine
The main power source for the Civic Hybrid is the 1.3-liter 4-cylinder i-DSI engine. The main characteristics of this design are low fuel consumption and high torque at low and medium speed ranges. The lean burn engine has a compression ratio of 10.8:1.

Engine Technical Highlights:

• High swirl effect inside combustion chamber aids combustion efficiency.
• Compact combustion chamber features a narrow angle valve layout (30-degrees) for added combustion efficiency.
• Compact single overhead cam (SOHC) head.
• Dual & Sequential Ignition (i-DSI) with two spark plugs per cylinder and precise sequential ignition results in ultra lean burn combustion and light off, less fuel consumed and clean exhaust emissions.
• VTEC-controlled Cylinder Idling System promotes low friction inside the engine (due to reduced pumping losses) during deceleration for increased regenerative braking capability.
• Automatic idle stop feature stops engine during complete stops for reduced fuel consumption and lower emissions.
• The 1.3-liter 4-cylinder i-DSI engine aluminum cylinder block uses a new frame structure technology for reduced weight and greater packaging flexibility.

1.3-Liter i-DSI Engine Specifications vs. 2002 Civic LX Sedan and 2002 Insight Engine Specifications

	2003 Civic Hybrid	2002 Civic LX Sedan	2002 Honda Insight
Displacement	1339 CC (1.3 L)	1668 CC (1.7 L)	995 CC (1.0 L)
No. of Cylinders	4	4	3
Horsepower (gas only)	85 @ 5700 rpm	110 @ 6100 rpm	67 @ 5700 rpm
Torque (gas only) ft.-lbs.	87 @ 3300 rpm	110 @ 4500 rpm	66 @ 4800 rpm
Horsepower (combined)	93 @ 5700 rpm	-	73 @ 5700 rpm
Torque (combined) (ft.-lbs.)	116 @ 1500 rpm (w/ MT) 105 @ 3000 rpm (w/ CVT)	- -	91 @ 2000 rpm (w/MT) 79 @ 1500 rpm (w/CVT)
Compression Ratio	10.8:1	9.5:1	10.8:1 MT / 10.3:1 CVT
Fuel Economy	CVT 48/48 est. city/hwy* MT 47/51 est. city/hwy*	AT 30/38 EPA city/hwy MT 30/38 EPA city/hwy	CVT 57/56 EPA city/hwy MT 61/68 EPA city/hwy
Emissions	ULEV	ULEV	ULEV(MT)/SULEV(CVT)

* Mileage figures represent Honda in-house estimates for comparison purposes only (not official EPA estimates).

Electric Motor Specifications

Voltage Rating	144 volts
Power Output (electric only)	13-horsepower/10kW@2500 to 4000 rpm
Torque (electric only)	46-ft-lbs torque @ 1000 rpm (w/ MT)*
	36-ft-lbs torque @ 1000 rpm (w/ CVT)*
Number of Phases	3
Number of Poles	12
Number of Slots	18

*Note that the torque ratings are different between the automatic continuously variable transmission model and the one equipped with a manual transmission. The engine control unit provides different amounts of power depending on the transmission to allow the vehicle to accelerate and perform with a feel appropriate for the acceleration characteristics of the transmission.

Battery Specifications

Battery Type	Nickel-Metal Hydride (Ni-MH)
Output	144 V (120 cells @ 1.2 Volts)
Capacity	6.0 AH
Weight	63 lbs.

Engine Block and Internal Components
The design concept for the 1.3-liter i-DSI aluminum engine block and its components focused on creating a lightweight package with extremely low friction qualities. To save weight, the block has thin sleeve construction. Friction reducing measures include plateau honing, low friction pistons, low tensile force piston rings and an offset cylinder bore.

• Thin sleeve cylinder wall construction results in a reduction of the total amount of aluminum used in the engine for a lightweight engine block.
• Plateau honing lowers the friction level between the pistons and the cylinders by creating an ultra smooth surface. Plateau honing is a two stage machining process that uses two grinding processes instead of the more conventional single honing process. This also enhances the long-term wear characteristics of the engine.
• Low friction pistons made of aluminum alloy are lightweight and have "micro-dimples" on the cylinder walls for improved lubrication.
• Offset cylinder bores help minimize friction by positioning the crankshaft axis in a more efficient alignment to the cylinder bore axis. This reduces friction caused by the side thrust of the pistons against the cylinder walls, just after top-dead-center, as each piston begins its descent on the firing stroke.
• Connecting rods are special high strength forged steel units that have been treated with a special carbon process that hardens the surface and allows engineers to use a design that weighs less than a traditional rod for this application.
• Low tensile force piston rings further reduce friction.

i-DSI (Dual & Sequential Ignition) with Twin Plug Sequential Ignition Control
The i-DSI Twin Plug Sequential Ignition Control helps facilitate an intense and rapid combustion process in the engine. In order to ignite as much of the air/fuel mixture as possible, the plugs are positioned to ignite precisely with the intake and exhaust ports in a sequential fashion under certain circumstances. When the air/fuel mixture enters the combustion chamber on the intake side, the first plug located near the intake port ignites. Shortly thereafter, the second plug located near the exhaust port ignites (in a sequential fashion), accelerating the combustion process by forcing the flame to rapidly propagate. The spark plugs can also ignite simultaneously under certain circumstances. This process results in a more complete combustion compared to a single plug system. The ignition control has eight ignition coils that are independently controlled according to a dynamic engine map program. The benefits are more power, less fuel consumption and reduced emissions. Honda's patented Twin Plug Sequential Control system is programmed to respond to engine rpm and load conditions. Since the system has eight individual ignition coils, it can manipulate the ignition timing of individual spark plugs located near the air intake port and the exhaust port.

Twin Plug Sequential Ignition Control System Program

Throttle Position	RPM	Ignition	Notes
Half	Low	Sequential	Air intake side has advanced ignition to balance torque and fuel economy.
Half	Mid - high	Simultaneous	Air intake and exhaust side spark plugs both simultaneously ignite to balance power and engine noise.
Full	Low	Sequential	The air intake side spark plug has advanced ignition and the exhaust side has delayed ignition for maximum torque.
Full	Medium	Sequential	Air intake side spark plug has advanced ignition and the exhaust side has further delayed ignition to balance torque and engine noise.
Full	High	Simultaneous	The air intake side spark plugs and the exhaust side spark plugs ignite simultaneously for maximum horsepower.

VTEC Controlled Cylinder Idling System
A major aspect of regenerative braking is to reclaim as much energy as possible during deceleration. Since the electric motor, which also acts as an electric generator, is attached directly to the crankshaft of the engine, the engine needs to provide as little resistance as possible during deceleration to allow the generator to produce high levels of electricity and charge the batteries. In a traditional engine, the pumping action of the cylinders will actually provide a moderate amount of resistance, or "engine braking," during deceleration (except in neutral or when the clutch is engaged in a manual transmission). The Cylinder Idling System effectively reduces engine drag by closing the intake and exhaust valves on up to three of the four cylinders and allowing the pistons to move more freely within the cylinders, thus allowing the generator to provide maximum resistance (instead of the engine) and, consequently, produce more electricity.

The system uses Honda's patented VTEC (Variable Valve Timing and Lift Electronic Control) technology to close the intake and exhaust valves on up to 3 of the 4 cylinders at rpms as low as 1000 to reduce the pumping action in the engine. Whereas traditional applications of VTEC engage an alternative cam profile at high rpm and high oil pressure for improved performance, this VTEC system engages at low rpm and low oil pressure to close the valves for a different kind of improved performance - reduced engine resistance during deceleration.

Lightweight Plastic Resin Intake Manifold Chamber
The engine's intake manifold chamber is constructed of a plastic resin instead of aluminum alloy in order to save weight. The individual pieces that make up the manifold chamber are permanently connected with a die-slide welding technique.

Lightweight Plastic Resin Engine Parts
In addition to the intake manifold chamber, engine components that make use of high strength plastic resin technology include the idler (tensioner) pulley.

Cylinder Head with Narrow Angle VTEC Valvetrain
The Civic Hybrid's single overhead camshaft (SOHC) cylinder head uses a compact chain drive and a compact, low friction VTEC system. It uses a common rocker shaft for both the intake and exhaust rocker arms. Placing all the rocker arms on one shaft eliminates the need for a second rocker-arm shaft, so the valve mechanism can be lighter and more compact. To reduce friction, the rocker arms have rollers built-in.

The compact valvetrain allows for a desirable narrow angle (30-degrees) between the intake and exhaust valves, which helps supply a more powerful direct charge into the cylinder chamber.

The narrow angle valvetrain allows for a more compact combustion chamber. The intake ports create a swirl effect in the cylinder chamber that promote a well balanced and even air fuel mixture as it enters the engine. This optimizes the air fuel mixture for a cleaner, more efficient combustion.

Exhaust and Emission System with Nitrogen Oxide Absorptive Catalytic Converter
Lean air-fuel ratios improve fuel economy and reduce hydrocarbons (HC), carbon monoxide (CO) and oxides of nitrogen (NOx). However, conventional 3-way catalysts are not very effective in converting NOx into normal nitrogen when excess oxygen is present. To keep NOx emissions within ULEV levels on various Honda vehicles, Honda engineers developed a nitrogen-oxide-absorptive catalytic converter. The catalyst uses a proprietary mixture of platinum and other metals to attract NOx molecules to its surface during lean air-fuel mixture combustion. Then, when the IMA engine is operating with a richer air-fuel ratio, the catalyst combines these NOx molecules with the hydrocarbons and CO present in the exhaust to form water vapor, carbon dioxide and nitrogen. The engine's nitrogen-oxide adsorptive catalyst plays an important role in helping the Civic Hybrid achieve ULEV emissions standards.

Engine Mounts
Engine mounts are optimally located over the axis of inertia, with consideration for the Civic Hybrid power unit's vibration characteristics. Moreover, liquid seal mounts are employed on the engine sides and transmission to dampen vibration. These features significantly reduce vibration from the power unit, resulting in a more comfortable ride.