Renix
Encyclopedia
Renix made automobile electronic ignitions, fuel injection
systems, electronic automatic transmission controls, and various engine sensors.
The term Renix also has a number of applications. In certain carburetor
equipped Renault
and Volvo
models, it provides an electronic ignition system, consisting of an engine control unit
(ECU) to replace the job of contact breaker points in the distributor. The system uses an angle sensor and a number of fuel sensors to provide a maintenance-free ignition system. The ECU is sealed and cannot be serviced, and the EPROM
cannot be re-programmed.
Later, the name was synonymous with a form of fuel injection. In such an application, it consisted of an ECU and a number of sensors. It was first seen in engines produced by Renault (Renault 21
, 25
, and Espace
) in 2 l (122 cu in) and 2.2 l (134 cu in) capacities. It is better known in America for its application in the AMC 4.0 L displacing 3960 cc straight-6 engines. Production began by American Motors
(AMC) with the 1987 Jeep Cherokee (XJ)
models. It was preceded by the AMC Computerized Engine Control
, and followed by the Mopar MPI system.
by Renault
with 51% interest and Bendix
with 49% that was headquartered in Toulouse
. When Renault encountered financial troubles in 1985, it sold its interest in Renix to AlliedSignal Corp., a major auto industry supplier and the new owner of Bendix.
Renix Corporation of America was the North American subsidiary of Renix Electronique and was formed to provided Sales, Logistics, Engineering and Quality support to American Motors. Renix Corporation of America was also absorbed by AlliedSignal Corporation when it purchased Renix Electronique from Renault.
, and an Electronic Control Unit (ECU). The Renix ECU has a powerful microprocessor
that was advanced technology for its time. It also incorporates an engine knocking
sensor that allows the computer to know if detonation
is occurring, thus allowing the computer to make adaptive control
by individual cylinder corrections to prevent pinging. The knock detection uses the signal from a wide bank accelerometer
mounted on the cylinder head
. Good signal to noise ratio
is obtained primarily through angular discrimination.
The Renix system has more inputs than the later Mopar system and in some ways is more complex. Its knock sensor automatically tunes the spark advance curve to an optimum mix for each cylinder. Some Renix controlled engines will actually get better fuel economy
using higher octane fuel.
The Renix computer was first used on 1986 AMC 2.5 L four-cylinder engines
s. The system improved the drivability of the Jeep Cherokee XJ models and the Comanche pickups over the first two months of production that were fitted with carburetors. The power increase was also noticeable. The Renix system was used through the 1990 model year. Unfortunately, the Renix system is now handicapped because there are few scan tools that can be "plugged in" to this on-board diagnostics
computer.
Model years:
The Renix control system was only found on the 1987-1990 Jeep Cherokee and Comanche with AMC-designed engines (the control setup used with the 2.8 l (171 cu in) V6
was OBD-I General Motors, and the early Diesel was a 2.1 l (128 cu in) Renault
turbodiesel
I4 that used its own specific control setup.)
The CJ/YJ "Universal" Jeep Wrangler
did not get the AMC 4.0 engine until 1991, when it was accompanied by Chrysler-designed electronics as well. Until then, it retained the AMC 258 CID engine with a carburetor
. No other Jeep vehicle was equipped with Renix electronic controls.
that can be removed and serviced separately. Electronic signals from the ECU to the ICM determine the amount of ignition timing or retard needed to meet engine power requirements. The ECU provides an input signal to the ICM. The ICM has outputs for a tach signal to the tachometer
and a high voltage signal from the coil to the distributor
. The crankshaft position sensor senses TDC (Top Dead Center) and BDC crankshaft positions, as well as engine RPM. This sensor is secured by special shouldered bolts to flywheel/drive plate housing and is not adjustable.
. This is a common problem at vehicle inspection
, particularly in California and other jurisdictions with emission standard
s. Most inspection stations are not aware and will try to explain that the CEL/MIL "doesn't work" (note: there may be a cutout for it, but no bulb). It is recommended that the inspection technician be shown the "OBD Exempt" federal emissions label (located under the hood) and/or have the factory service manual as a reference to avoid this problem.
and some of the Volvo 300 Series
used a B200K 2.0 L inline-4 naturally aspirated engine with Renix ignition and some 300 series Volvos with Renault powerplants. The 300 Volvo series is not known U.S. It was manufactured in Holland and some units in Australia for the local Right Hand Drive (RHD) market.
All 300 series Volvo cars with gasoline engines came with Renix/Bendix ignition 1983 onwards until 1991 when production of the 300 series stopped.
Engines equipped with Renix ignition:
Renault (F [=OHC] and C [=OHV Pushrod] series) units:
Fuel injection
Fuel injection is a system for admitting fuel into an internal combustion engine. It has become the primary fuel delivery system used in automotive petrol engines, having almost completely replaced carburetors in the late 1980s....
systems, electronic automatic transmission controls, and various engine sensors.
The term Renix also has a number of applications. In certain carburetor
Carburetor
A carburetor , carburettor, or carburetter is a device that blends air and fuel for an internal combustion engine. It is sometimes shortened to carb in North America and the United Kingdom....
equipped Renault
Renault
Renault S.A. is a French automaker producing cars, vans, and in the past, autorail vehicles, trucks, tractors, vans and also buses/coaches. Its alliance with Nissan makes it the world's third largest automaker...
and Volvo
Volvo
AB Volvo is a Swedish builder of commercial vehicles, including trucks, buses and construction equipment. Volvo also supplies marine and industrial drive systems, aerospace components and financial services...
models, it provides an electronic ignition system, consisting of an engine control unit
Engine control unit
An engine control unit is a type of electronic control unit that determines the amount of fuel, ignition timing and other parameters an internal combustion engine needs to keep running...
(ECU) to replace the job of contact breaker points in the distributor. The system uses an angle sensor and a number of fuel sensors to provide a maintenance-free ignition system. The ECU is sealed and cannot be serviced, and the EPROM
EPROM
An EPROM , or erasable programmable read only memory, is a type of memory chip that retains its data when its power supply is switched off. In other words, it is non-volatile. It is an array of floating-gate transistors individually programmed by an electronic device that supplies higher voltages...
cannot be re-programmed.
Later, the name was synonymous with a form of fuel injection. In such an application, it consisted of an ECU and a number of sensors. It was first seen in engines produced by Renault (Renault 21
Renault 21
The Renault 21 is a large family car produced by French automaker Renault between 1986 and 1994. It was also sold in North America through American Motors dealers as the Renault Medallion and the Eagle Medallion...
, 25
Renault 25
The Renault 25 is an executive car produced by the French automaker Renault from 1983 to 1992. During its time, the 25 was Renault's flagship, the most expensive, prestigious, and largest vehicle in the company's line-up. It placed second in the 1985 European Car of the Year contest...
, and Espace
Renault Espace
The Renault Espace is a large MPV from French car-maker Renault. Generations 1-3 were sold under the Renault brand but manufactured by Matra. The current fourth generation model, which seats seven passengers, is an all-Renault product; the Renault Grand Espace is a long-wheelbase version with...
) in 2 l (122 cu in) and 2.2 l (134 cu in) capacities. It is better known in America for its application in the AMC 4.0 L displacing 3960 cc straight-6 engines. Production began by American Motors
American Motors
American Motors Corporation was an American automobile company formed by the 1954 merger of Nash-Kelvinator Corporation and Hudson Motor Car Company. At the time, it was the largest corporate merger in U.S. history.George W...
(AMC) with the 1987 Jeep Cherokee (XJ)
Jeep Cherokee (XJ)
The Jeep Cherokee is a unibody compact SUV. It shared the name of the original full-size SJ model, but without a body-on-frame chassis, it set the stage for the modern SUV. Its innovative appearance and sales popularity spawned important imitators as other automakers began to notice that this...
models. It was preceded by the AMC Computerized Engine Control
AMC Computerized Engine Control
The Computerized Engine Control or CEC system was an engine management system designed and used by American Motors and Jeep from 1980-1990, on the AMC 258 engine....
, and followed by the Mopar MPI system.
Renix Electronique
Renix Electronique S.A., was established in 1981 as a joint ventureJoint venture
A joint venture is a business agreement in which parties agree to develop, for a finite time, a new entity and new assets by contributing equity. They exercise control over the enterprise and consequently share revenues, expenses and assets...
by Renault
Renault
Renault S.A. is a French automaker producing cars, vans, and in the past, autorail vehicles, trucks, tractors, vans and also buses/coaches. Its alliance with Nissan makes it the world's third largest automaker...
with 51% interest and Bendix
Bendix Corporation
The Bendix Corporation was an American manufacturing and engineering company which during various times in its 60 year existence made brake systems, aeronautical hydraulics, avionics, aircraft and automobile fuel control systems, radios, televisions and computers, and which licensed its name for...
with 49% that was headquartered in Toulouse
Toulouse
Toulouse is a city in the Haute-Garonne department in southwestern FranceIt lies on the banks of the River Garonne, 590 km away from Paris and half-way between the Atlantic Ocean and the Mediterranean Sea...
. When Renault encountered financial troubles in 1985, it sold its interest in Renix to AlliedSignal Corp., a major auto industry supplier and the new owner of Bendix.
Renix Corporation of America was the North American subsidiary of Renix Electronique and was formed to provided Sales, Logistics, Engineering and Quality support to American Motors. Renix Corporation of America was also absorbed by AlliedSignal Corporation when it purchased Renix Electronique from Renault.
Renault applications
The Renix system was used in the J series engines as fitted to the Renault 21 and Savanna/Nevada, the Renault 25, and the Renault Espace. It was a multi-point fuel injection system, as opposed to a single-point system, with a number of air, throttle and pinking sensors, and an advanced computer. Application of the system could first be seen in 1984, three years before its American debut. The Renix system pushed the power of the carburetor-fed 1995 cc engine from 104 bhp. It could also be found in 2.2 L engines fitted to R21, 25, and Espace models.AMC/Jeep applications
The Renix electronic ignition system consists of a solid-state Ignition Control Module (ICM), a distributor, a crankshaft position sensorCrankshaft position sensor
A crank position sensor is an electronic device used in an internal combustion engine to monitor the position or rotational speed of the crankshaft. This information is used by engine management systems to control ignition system timing and other engine parameters...
, and an Electronic Control Unit (ECU). The Renix ECU has a powerful microprocessor
Microprocessor
A microprocessor incorporates the functions of a computer's central processing unit on a single integrated circuit, or at most a few integrated circuits. It is a multipurpose, programmable device that accepts digital data as input, processes it according to instructions stored in its memory, and...
that was advanced technology for its time. It also incorporates an engine knocking
Engine knocking
Knocking in spark-ignition internal combustion engines occurs when combustion of the air/fuel mixture in the cylinder starts off correctly in response to ignition by the spark plug, but one or more pockets of air/fuel mixture explode outside the envelope of the normal combustion front.The...
sensor that allows the computer to know if detonation
Detonation
Detonation involves a supersonic exothermic front accelerating through a medium that eventually drives a shock front propagating directly in front of it. Detonations are observed in both conventional solid and liquid explosives, as well as in reactive gases...
is occurring, thus allowing the computer to make adaptive control
Adaptive control
Adaptive control is the control method used by a controller which must adapt to a controlled system with parameters which vary, or are initially uncertain. For example, as an aircraft flies, its mass will slowly decrease as a result of fuel consumption; a control law is needed that adapts itself...
by individual cylinder corrections to prevent pinging. The knock detection uses the signal from a wide bank accelerometer
Accelerometer
An accelerometer is a device that measures proper acceleration, also called the four-acceleration. This is not necessarily the same as the coordinate acceleration , but is rather the type of acceleration associated with the phenomenon of weight experienced by a test mass that resides in the frame...
mounted on the cylinder head
Cylinder head
In an internal combustion engine, the cylinder head sits above the cylinders on top of the cylinder block. It closes in the top of the cylinder, forming the combustion chamber. This joint is sealed by a head gasket...
. Good signal to noise ratio
Signal-to-noise ratio
Signal-to-noise ratio is a measure used in science and engineering that compares the level of a desired signal to the level of background noise. It is defined as the ratio of signal power to the noise power. A ratio higher than 1:1 indicates more signal than noise...
is obtained primarily through angular discrimination.
The Renix system has more inputs than the later Mopar system and in some ways is more complex. Its knock sensor automatically tunes the spark advance curve to an optimum mix for each cylinder. Some Renix controlled engines will actually get better fuel economy
Fuel economy in automobiles
Fuel usage in automobiles refers to the fuel efficiency relationship between distance traveled by an automobile and the amount of fuel consumed....
using higher octane fuel.
The Renix computer was first used on 1986 AMC 2.5 L four-cylinder engines
AMC Straight-4 engine
The American Motors Corporation straight-4 engine was used by a number of AMC, Jeep, and Dodge vehicles from 1984-2002.*For an outline of all engines used by AMC see -Development:...
s. The system improved the drivability of the Jeep Cherokee XJ models and the Comanche pickups over the first two months of production that were fitted with carburetors. The power increase was also noticeable. The Renix system was used through the 1990 model year. Unfortunately, the Renix system is now handicapped because there are few scan tools that can be "plugged in" to this on-board diagnostics
On-board diagnostics
On-Board Diagnostics, or OBD, in an automotive context, is a generic term referring to a vehicle's self-diagnostic and reporting capability. OBD systems give the vehicle owner or a repair technician access to state of health information for various vehicle sub-systems...
computer.
Model years:
- 1986 - Renix TBI available on Jeep 2.5 L four-cylinder engines.
- 1987 - the new Renix controlled 4.0 L six-cylinder engine was rated at 173 hp and 220 ft-lb (298 N·m) of torque.
- 1988 - 4.0 L output increased to 177 hp and 224 ft-lb (304 N·m) of torque, due to higher compression ratio.
- 1989 - Changed to Renix MPFI.
- 1991 - Chrysler Corporation (then the owners of the Jeep brand replaced the Renix control system with OBD-I-compliant control electronics, the Chrysler HO EFI.
The Renix control system was only found on the 1987-1990 Jeep Cherokee and Comanche with AMC-designed engines (the control setup used with the 2.8 l (171 cu in) V6
GM 60-Degree V6 engine
The General Motors 60° V6 family of engines began with the 1980 Chevrolet 2.8 L V6 and continues to be produced today . Its use in the X-body cars leads some to refer to it as the X engine.It is a 60° vee block with pushrod heads, except for a single DOHC member, the LQ1...
was OBD-I General Motors, and the early Diesel was a 2.1 l (128 cu in) Renault
Renault
Renault S.A. is a French automaker producing cars, vans, and in the past, autorail vehicles, trucks, tractors, vans and also buses/coaches. Its alliance with Nissan makes it the world's third largest automaker...
turbodiesel
Turbodiesel
Turbodiesel refers to any diesel engine with a turbocharger. Turbocharging is the norm rather than the exception in modern car and truck diesel engines...
I4 that used its own specific control setup.)
The CJ/YJ "Universal" Jeep Wrangler
Jeep Wrangler
The Jeep Wrangler is a subcompact four-wheel drive sport utility vehicle and an off-road vehicle manufactured by American automaker Chrysler, under its Jeep marque – and now in its fourth generation. It is a successor to the famous World War II 'Jeep' vehicle by way of the Willys civilian...
did not get the AMC 4.0 engine until 1991, when it was accompanied by Chrysler-designed electronics as well. Until then, it retained the AMC 258 CID engine with a carburetor
Carburetor
A carburetor , carburettor, or carburetter is a device that blends air and fuel for an internal combustion engine. It is sometimes shortened to carb in North America and the United Kingdom....
. No other Jeep vehicle was equipped with Renix electronic controls.
Operation
In a typical Jeep application, the ignition control module (ICM) is located in engine compartment. It consists of a solid-state ignition circuit, as well as an integrated ignition coilIgnition coil
An ignition coil is an induction coil in an automobile's ignition system which transforms the battery's 12 volts to the thousands of volts needed to create an electric spark in the spark plugs to ignite the fuel...
that can be removed and serviced separately. Electronic signals from the ECU to the ICM determine the amount of ignition timing or retard needed to meet engine power requirements. The ECU provides an input signal to the ICM. The ICM has outputs for a tach signal to the tachometer
Tachometer
A tachometer is an instrument measuring the rotation speed of a shaft or disk, as in a motor or other machine. The device usually displays the revolutions per minute on a calibrated analogue dial, but digital displays are increasingly common...
and a high voltage signal from the coil to the distributor
Distributor
A distributor is a device in the ignition system of an internal combustion engine that routes high voltage from the ignition coil to the spark plugs in the correct firing order. The first reliable battery operated ignition was developed by Dayton Engineering Laboratories Co. and introduced in the...
. The crankshaft position sensor senses TDC (Top Dead Center) and BDC crankshaft positions, as well as engine RPM. This sensor is secured by special shouldered bolts to flywheel/drive plate housing and is not adjustable.
Inspection stations
The Renix control system is "pre-OBD," and therefore does not have a "Check Engine Lamp". It also does not "store" or "throw" Diagnostic Trouble Codes (DTCs) or "Parameter IDs" (PIDs) - see: OBD-II PIDsOBD-II PIDs
OBD-II PIDs are codes used to request data from a vehicle, used as a diagnostic tool. SAE standard J/1979 defines many PIDs, but manufacturers also define many more PIDs specific to their vehicles...
. This is a common problem at vehicle inspection
Vehicle inspection
Vehicle inspection is a procedure mandated by national or subnational governments in many countries, in which a vehicle is inspected to ensure that it conforms to regulations governing safety, emissions, or both. Inspection can be required at various times, e.g., periodically or on transfer of...
, particularly in California and other jurisdictions with emission standard
Emission standard
Emission standards are requirements that set specific limits to the amount of pollutants that can be released into the environment. Many emissions standards focus on regulating pollutants released by automobiles and other powered vehicles but they can also regulate emissions from industry, power...
s. Most inspection stations are not aware and will try to explain that the CEL/MIL "doesn't work" (note: there may be a cutout for it, but no bulb). It is recommended that the inspection technician be shown the "OBD Exempt" federal emissions label (located under the hood) and/or have the factory service manual as a reference to avoid this problem.
Volvo applications
The Volvo 700 SeriesVolvo 700 series
The 760 was Volvo's attempt to cement a place in the prestige market, after building a reputation for being solid and safe rather than out-and-out luxurious cars. Jan Wilsgaard, head of Volvo's Design and Styling team, proposed over 50 new designs for the new car. It was introduced to the US in...
and some of the Volvo 300 Series
Volvo 300 series
The Volvo 300 series is a rear wheel drive automobile sold as both a hatchback and a conventional saloon from 1976-1991. It was launched in the Netherlands shortly after Volvo acquired a major stake in the passenger car division of DAF in 1973...
used a B200K 2.0 L inline-4 naturally aspirated engine with Renix ignition and some 300 series Volvos with Renault powerplants. The 300 Volvo series is not known U.S. It was manufactured in Holland and some units in Australia for the local Right Hand Drive (RHD) market.
All 300 series Volvo cars with gasoline engines came with Renix/Bendix ignition 1983 onwards until 1991 when production of the 300 series stopped.
Engines equipped with Renix ignition:
- Volvo 1986ccm 2.0 L units
- Volvo 1721ccm B18E(D) engines in 400 series 1986-1988
- B200K 100 hp Solex Cisac Z34 twin barrel carburetor 1985-1989
- B200E 111 hp Bosch LE-jetronic injected unit 1985-1989
- B200F 108 hp Bosch LU-jetronic injected and catalyzed engine 1987-1990
Renault (F [=OHC] and C [=OHV Pushrod] series) units:
- B172K 1.7 L OHC 78 hp Solex Cisaz Z32 carburetor 1986-1989
- B14.4E/S 1.4 L OHV 72 hp Weber 32DIR carburetor 1985-1991
- B14.3E/S OHV 64 hp single barrel Solex carburetor version 1983-1985
- B13.4E 1.3 L OHV 64 hp Weber 32DIR Carburetor unit aimed for FinnishFinlandFinland , officially the Republic of Finland, is a Nordic country situated in the Fennoscandian region of Northern Europe. It is bordered by Sweden in the west, Norway in the north and Russia in the east, while Estonia lies to its south across the Gulf of Finland.Around 5.4 million people reside...
markets (where 1.3 L was a tax-class) 1989-1991
See also
- AMC Straight-6 engineAMC Straight-6 engineThe American Motors Corporation straight-6 family of engines was used by a number of AMC and Jeep vehicles from 1964 through 2006.-195.6:American Motors' first straight-six engine was the...
- AMC Engines
- List of Chrysler engines
- Allpar's page