The 1999-2003 Chrysler Concorde/Dodge Intrepid Environmental Features

Vehicle Emission Controls

Both new Concorde and Intrepid engines are designed to meet year 2000 exhaust emission regulations by minimizing the output of pollutants at the engine, thereby limiting the demand on downstream control devices. Both engines produce 30 percent less hydrocarbon (unburned fuel) emissions than their 1997 predecessors. In most states and foreign markets, the engines meet the federal Tier 1 emission standards. In California and states that adopt their standards, the engines meet more stringent TLEV (Transition Low Emission Vehicle) emission standards by using more effective (and expensive) catalytic converters. Both engines are available in both markets.

The emission control system includes the following features:

• Dual, close-coupled catalytic converters reach operating temperature faster than those in any prior Chrysler emission system because of their proximity to the engine [webmaster note: you can see it under the hood!]. This results in a 30 percent reduction of mass over the previous three-converter system. The federal configuration also uses 30-40 percent less precious metal than the prior system. To reduce underhood space requirements, these converters use a substrate of high-grade stainless steel foil on which the catalytic coating is applied. The stainless steel foil is less bulky than available ceramic substrates
• The top piston ring is 45 percent closer to the piston crown than on prior Concorde and Intrepid engines. This minimizes the volume of the crevice where fuel does not burn and may be expelled to the atmosphere as a pollutant if not oxidized by the catalytic converter. Because the top piston ring is now closer to the combustion process, it operates at a higher temperature and therefore, the top piston ring groove is anodized to prevent the ring from sticking
• Nitrogen oxide emissions are reduced by using recirculated exhaust to thoroughly mix the incoming charge of fuel and air in the high turbulence combustion chambers. The intake port and valve configuration imparts the turbulence by making the fuel, air and exhaust gas tumble as they enter the cylinder, resulting in very efficient combustion
• Coil-on plug ignition provides individual, high-energy secondary coils which are connected directly to each spark plug, providing more than a 28 percent power increase over the former direct ignition system (DIS). This allows for improved ignition of the lean mixtures in the high turbulance combustion chambers, which are necessary for reduced emissions. In the 3.2-liter engine, the coils provide 60 percent more energy during cold starts and warm-up, allowing for a leaner (and cleaner) fuel and air mixture. The combustion process is also hotter, producing the hot exhaust gasses necessary to quickly heat the catalysts to get them to peak operating temperature quickly
• Exhaust ports are as small as possible without adversely affecting power to quickly heat the catalytic converters to operating temperature. Because heat in the exhaust stream transfers to the head as exhaust flows through the ports, reducing port size reduces the surface area to which the heat can transfer. Small ports also result in high velocity flow, leaving little time for heat transfer.
• Short cylinder bore water jackets contribute to more complete combustion. Water jacket coverage has been reduced nearly 50 percent-from 1.5 times the piston stroke to only 80 percent, providing a more uniform temperature throughout the piston stroke. The greatest amount of heat is created at the top of the piston stroke and the temperature in the cylinder diminishes as the mixture expands and the piston is driven downward. By limiting the water jacket to the top portion of the cylinder, the lower portion stays hotter. This allows combustion to continue longer because the cylinder does not quench the flame by cooling the combustion products. Computational Fluid Dynamics (CFD) showed how to reduce coolant volume for higher temperatures without causing localized overheating
• Fuel injectors are mounted directly in the cylinder head allowing for a very wide spray pattern of injected fuel, without wetting the cylinder walls. (Wetting increases emissions by leaving unburned fuel in the chamber). The wide spray produces very fine atomization of the incoming fuel charge allowing for a very complete burn, thus reducing hydrocarbon emissions
• A synchronous fuel injection timing ensures that fuel arrives when the intake valves are open, mixing thoroughly with the incoming air
• LS EGR (linear solenoid exhaust gas recirculation) uses a linear solenoid valve controlled by the Power Train Control Module (PCM) to provide the precise amount exhaust flow to the intake manifold, which is needed for optimum reduction of nitrogen oxide exhaust emissions. EGR flow to individual cylinders was mapped and fine tuned using CFD
• Inlet-side, bypass-type thermostats provide a smoother introduction of coolant from the radiator to the block during warm-up compared with an outlet-side system. This allows closer control of fuel flow and ignition timing, which is tied to coolant temperature during warm-up. Because it immediately senses the temperature of the incoming coolant, it only allows short bursts until the radiator and block temperatures stabilize. An outlet-side thermostat tends to permit large bursts of low-temperature coolant into the block during warm-up because the lower temperature is not sensed until this flow reaches the thermostat. This chills the cylinders briefly, sometimes causing the control system to return to a richer fuel mixture that increases emissions and reduces fuel economy
• Quad oxygen sensors mounted in the front and back of each catalytic converter (a total of four) provide precise side-to-side control of fuel injection rate and monitor catalytic converter efficiency as required by emission control standards. In addition, they enable fine tuning of the fuel-to-air ratio, keeping tail pipe emissions low throughout the life of the vehicle
• Low-mass exhaust manifolds constructed of lightweight, thin-wall cast iron absorb little heat from
• the exhaust stream, speeding catalytic converter warm up. Faster catalyst warm-up reduces emissions
• Differential intake and exhaust valve height on the 2.7-liter engine reduces emissions, because the exhaust valves are higher in the combustion chambers than the intake valves. This allows a vortex of condensing unburned fuel vapor to be pushed up the cylinder by the piston during the exhaust stroke instead of the exhaust stream. This remnant remains in the cylinder to be burned during the next cycle, reducing emissions that must be treated by the catalytic converter
• A combined charge-air temperature and manifold absolute pressure sensor (T-MAP) on the 3.2-liter engine gives more accurate temperature readings than the prior charge sensor location

On-Board Diagnostics - Evaporative System Leak Detection

A leak detection system, similar to that used on other Chrysler vehicles since 1996, mounts close to the fuel tank on cars meeting California emission requirements. The leak detection system includes a leak detection pump that lightly pressurizes the entire fuel supply system periodically to verify that vapor is not escaping. If vapor leakage exceeds the flow through a 0.040-in. (1mm) orifice, the OBD II (on-board diagnostic system) turns on the 'CHECK ENGINE' light.

Environmentally Friendly Materials and Processes

The following environmentally friendly materials and processes are used on the 1998 Concorde and Intrepid:

• The RRIM fascias used on Concorde include 5 percent post-consumer recycled material.
• The molded urethane steering wheel rim uses water, rather than CFCs, as the expansion agent to help protect the atmosphere.
• New engine coolant formulation uses 100 percent post consumer ethylene glycol as a base.
• All base coat paint is water-borne, greatly reducing the amount of VOCs (volatile organic compounds) vented to the atmosphere. The electro-coat primer remains a low-VOC water-borne material.
• New intake manifolds on all engines are made from recyclable PA 66 nylon.
• Air induction system components, including the air cleaner housing are made of recyclable PA 66 nylon or polypropylene.

As on the prior Concorde and Intrepid, the substrate of the interior roof system is made from sound insulating AcoustiCor®, which is primarily recycled polyethylene terepthalate (PET) soft drink bottles reinforced with glass fiber. A further refinement of the recycling process is the recycling of the AcoustiCor headliners into a new material called EcoCor® for which applications are sought.